40 CFR Part 1065 — Engine-Testing Procedures

PART 1065—ENGINE-TESTING PROCEDURES Authority: 42 U.S.C. 7401-7671q. Source: 70 FR 40516, July 13, 2005, unless otherwise noted. Subpart A—Applicability and General Provisions § 1065.1 Applicability. (a) This part describes the procedures that apply to testing we require for the following engines or for vehicles using the following engines: (1) Locomotives we regulate under 40 CFR part 1033. (2) Heavy-duty highway engines we regulate under 40 CFR parts 86 and 1036. (3) Nonroad compression-ignition engines we regulate under 40 CFR part 1039 and stationary diesel engines that are certified to the standards in 40 CFR part 1039 as specified in 40 CFR part 60, subpart IIII. (4) Marine compression-ignition engines we regulate under 40 CFR part 1042. (5) Marine spark-ignition engines we regulate under 40 CFR part 1045. (6) Large nonroad spark-ignition engines we regulate under 40 CFR part 1048, and stationary engines that are certified to the standards in 40 CFR part 1048 or as otherwise specified in 40 CFR part 60, subpart JJJJ. (7) Vehicles we regulate under 40 CFR part 1051 (such as snowmobiles and off-highway motorcycles) based on engine testing. See 40 CFR part 1051, subpart F, for standards and procedures that are based on vehicle testing. (8) Small nonroad spark-ignition engines we regulate under 40 CFR part 1054 and stationary engines that are certified to the standards in 40 CFR part 1054 as specified in 40 CFR part 60, subpart JJJJ. (b) The procedures of this part may apply to other types of engines, as described in this part and in the standard-setting part. (c) The term “you” means anyone performing testing under this part other than EPA. (1) This part is addressed primarily to manufacturers of engines, vehicles, equipment, and vessels, but it applies equally to anyone who does testing under this part for such manufacturers. (2) This part applies to any manufacturer or supplier of test equipment, instruments, supplies, or any other goods or services related to the procedures, requirements, recommendations, or options in this part. (d) Paragraph (a) of this section identifies the parts of the CFR that define emission standards and other requirements for particular types of engines. In this part, we refer to each of these other parts generically as the ”standard-setting part.” For example, 40 CFR part 1051 is always the standard-setting part for snowmobiles. Note that while 40 CFR part 86 is the standard-setting part for heavy-duty highway engines, this refers specifically to 40 CFR part 86, subpart A, and to certain portions of 40 CFR part 86, subpart N, as described in 40 CFR 86.1301. (e) Unless we specify otherwise, the terms “procedures” and “test procedures” in this part include all aspects of engine testing, including the equipment specifications, calibrations, calculations, and other protocols and procedural specifications needed to measure emissions. (f) For vehicles, equipment, or vessels subject to this part and regulated under vehicle-based, equipment-based, or vessel-based standards, use good engineering judgment to interpret the term “engine” in this part to include vehicles, equipment, or vessels, where appropriate. (g) For additional information regarding the test procedures in this part, visit our website at www.epa.gov, https://www.epa.gov/vehicle-and-fuel-emissions-testing/engine-testing-regulations. (h) This part describes procedures and specifications for measuring an engine's exhaust emissions. While the measurements are geared toward engine-based measurements (in units of g/kW · hr), many of these provisions apply equally to vehicle-based measurements (in units of g/mile or g/kilometer). 40 CFR part 1066 describes the analogous procedures for vehicle-based emission measurements, and in many cases states that specific provisions of this part 1065 also apply for those vehicle-based measurements. Where material from this part 1065 applies for vehicle-based measurements under 40 CFR part 1066, it is sometimes necessary to include parenthetical statements in this part 1065 to properly cite secondary references that are different for vehicle-based testing. See 40 CFR part 1066 and the standard-setting part for additional information. (i) The following additional procedures apply as described in subpart L of this part: (1) Measuring brake-specific emissions of semi-volatile organic compounds, which are not subject to separate emission standards. (2) Identifying the threshold temperature for vanadium sublimation for SCR catalysts. (3) Measuring the smoke opacity of engine exhaust. (4) Aging aftertreatment devices in support of determining deterioration factors for certified compression-ignition engines. [73 FR 37288, June 30, 2008, as amended at 73 FR 59321, Oct. 8, 2008; 75 FR 23028, Apr. 30, 2010; 76 FR 37977, June 28, 2011; 76 FR 57437, Sept. 15, 2011; 79 FR 23752, Apr. 28, 2014; 86 FR 34533, June 29, 2021; 88 FR 4669, Jan. 24, 2023] § 1065.2 Submitting information to EPA under this part. (a) You are responsible for statements and information in your applications for certification, requests for approved procedures, selective enforcement audits, laboratory audits, production-line test reports, field test reports, or any other statements you make to us related to this part 1065. If you provide statements or information to someone for submission to EPA, you are responsible for these statements and information as if you had submitted them to EPA yourself. (b) In the standard-setting part and in 40 CFR 1068.101, we describe your obligation to report truthful and complete information and the consequences of failing to meet this obligation. See (c) We may void any certificates or approvals associated with a submission of information if we find that you intentionally submitted false, incomplete, or misleading information. For example, if we find that you intentionally submitted incomplete information to mislead EPA when requesting approval to use alternate test procedures, we may void the certificates for all engine families certified based on emission data collected using the alternate procedures. This paragraph (c) would also apply if you ignore data from incomplete tests or from repeat tests with higher emission results. (d) We may require an authorized representative of your company to approve and sign the submission, and to certify that all the information submitted is accurate and complete. This includes everyone who submits information, including manufacturers and others. (e) See 40 CFR 1068.10 for provisions related to confidential information. Note however that under 40 CFR 2.301, emission data are generally not eligible for confidential treatment. (f) Nothing in this part should be interpreted to limit our ability under Clean Air Act section 208 (42 U.S.C. 7542) to verify that engines conform to the regulations. [73 FR 37289, June 30, 2008, as amended at 75 FR 23028, Apr. 30, 2010; 79 FR 23752, Apr. 28, 2014; 86 FR 34533, June 29, 2021] § 1065.5 Overview of this part 1065 and its relationship to the standard-setting part. (a) This part specifies procedures that apply generally to measuring brake-specific emissions from various categories of engines. See subpart L of this part for measurement procedures for testing related to standards other than brake-specific emission standards. See the standard-setting part for directions in applying specific provisions in this part for a particular type of engine. Before using this part's procedures, read the standard-setting part to answer at least the following questions: (1) What duty cycles must I use for laboratory testing? (2) Should I warm up the test engine before measuring emissions, or do I need to measure cold-start emissions during a warm-up segment of the duty cycle? (3) Which exhaust constituents do I need to measure? Measure all exhaust constituents that are subject to emission standards, any other exhaust constituents needed for calculating emission rates, and any additional exhaust constituents as specified in the standard-setting part. Alternatively, you may omit the measurement of N 2 4 2 4 2 4 (4) Do any unique specifications apply for test fuels? (5) What maintenance steps may I take before or between tests on an emission-data engine? (6) Do any unique requirements apply to stabilizing emission levels on a new engine? (7) Do any unique requirements apply to test limits, such as ambient temperatures or pressures? (8) Is field testing required or allowed, and are there different emission standards or procedures that apply to field testing? (9) Are there any emission standards specified at particular engine-operating conditions or ambient conditions? (10) Do any unique requirements apply for durability testing? (b) The testing specifications in the standard-setting part may differ from the specifications in this part. In cases where it is not possible to comply with both the standard-setting part and this part, you must comply with the specifications in the standard-setting part. The standard-setting part may also allow you to deviate from the procedures of this part for other reasons. (c) The following table shows how this part divides testing specifications into subparts: Table 1 of § 1065.5—Description of Part 1065 Subparts This subpart Describes these specifications or procedures Subpart A Applicability and general provisions. Subpart B Equipment for testing. Subpart C Measurement instruments for testing. Subpart D Calibration and performance verifications for measurement systems. Subpart E How to prepare engines for testing, including service accumulation. Subpart F How to run an emission test over a predetermined duty cycle. Subpart G Test procedure calculations. Subpart H Fuels, engine fluids, analytical gases, and other calibration standards. Subpart I Special procedures related to oxygenated fuels. Subpart J How to test with portable emission measurement systems (PEMS). Subpart L How to test for unregulated and special pollutants and to perform additional measurements related to certification. [73 FR 37289, June 30, 2008, as amended at 74 FR 56511, Oct. 30, 2009; 88 FR 4669, Jan. 24, 2023] § 1065.10 Other procedures. (a) Your testing. (b) Our testing. (c) Exceptions. (1) The objective of the procedures in this part is to produce emission measurements equivalent to those that would result from measuring emissions during in-use operation using the same engine configuration as installed in a vehicle, equipment, or vessel. However, in unusual circumstances where these procedures may result in measurements that do not represent in-use operation, you must notify us if good engineering judgment indicates that the specified procedures cause unrepresentative emission measurements for your engines. Note that you need not notify us of unrepresentative aspects of the test procedure if measured emissions are equivalent to in-use emissions. This provision does not obligate you to pursue new information regarding the different ways your engine might operate in use, nor does it obligate you to collect any other in-use information to verify whether or not these test procedures are representative of your engine's in-use operation. If you notify us of unrepresentative procedures under this paragraph (c)(1), we will cooperate with you to establish whether and how the procedures should be appropriately changed to result in more representative measurements. While the provisions of this paragraph (c)(1) allow us to be responsive to issues as they arise, we would generally work toward making these testing changes generally applicable through rulemaking. We will allow reasonable lead time for compliance with any resulting change in procedures. We will consider the following factors in determining the importance of pursuing changes to the procedures: (i) Whether supplemental emission standards or other requirements in the standard-setting part address the type of operation of concern or otherwise prevent inappropriate design strategies. (ii) Whether the unrepresentative aspect of the procedures affects your ability to show compliance with the applicable emission standards. (iii) The extent to which the established procedures require the use of emission-control technologies or strategies that are expected to ensure a comparable degree of emission control under the in-use operation that differs from the specified procedures. (2) You may request to use special procedures if your engine cannot be tested using the specified procedures. For example, this may apply if your engine cannot operate on the specified duty cycle. In this case, tell us in writing why you cannot satisfactorily test your engine using this part's procedures and ask to use a different approach. We will approve your request if we determine that it would produce emission measurements that represent in-use operation and we determine that it can be used to show compliance with the requirements of the standard-setting part. Where we approve special procedures that differ substantially from the specified procedures, we may preclude you from participating in averaging, banking, and trading with the affected engine families. (3) In a given model year, you may use procedures required for later model year engines without request. If you upgrade your testing facility in stages, you may rely on a combination of procedures for current and later model year engines as long as you can ensure, using good engineering judgment, that the combination you use for testing does not affect your ability to show compliance with the applicable emission standards. (4) In a given model year, you may ask to use procedures allowed for earlier model year engines. We will approve this only if you show us that using the procedures allowed for earlier model years does not affect your ability to show compliance with the applicable emission standards. (5) You may ask to use emission data collected using other procedures, such as those of the California Air Resources Board or the International Organization for Standardization. We will approve this only if you show us that using these other procedures does not affect your ability to show compliance with the applicable emission standards. (6) During the 12 months following the effective date of any change in the provisions of this part 1065 (and 40 CFR part 1066 for vehicle testing), you may use data collected using procedures specified in the previously applicable version of this part 1065 (and 40 CFR part 1066 for vehicle testing). This also applies for changes to test procedures specified in the standard-setting part to the extent that these changes do not correspond to new emission standards. This paragraph (c)(6) does not restrict the use of carryover certification data otherwise allowed by the standard-setting part. (7) You may request to use alternate procedures that are equivalent to the specified procedures, or procedures that are more accurate or more precise than the specified procedures. We may perform tests with your engines using either the approved alternate procedures or the specified procedures. The following provisions apply to requests for alternate procedures: (i) Applications. (ii) Submission. (iii) Notification. (d) Advance approval. [70 FR 40516, July 13, 2005, as amended at 73 FR 37290, June 30, 2008; 75 FR 23028, Apr. 30, 2010; 79 FR 23752, Apr. 28, 2014; 80 FR 9118, Feb. 19, 2015; 81 FR 74162, Oct. 25, 2016; 88 FR 4670, Jan. 24, 2023] § 1065.12 Approval of alternate procedures. (a) To get approval for an alternate procedure under § 1065.10(c), send the EPA Program Officer an initial written request describing the alternate procedure and why you believe it is equivalent to the specified procedure. Anyone may request alternate procedure approval. This means that an individual engine manufacturer may request to use an alternate procedure. This also means that an instrument manufacturer may request to have an instrument, equipment, or procedure approved as an alternate procedure to those specified in this part. We may approve your request based on this information alone, whether or not it includes all the information specified in this section. Where we determine that your original submission does not include enough information for us to determine that the alternate procedure is equivalent to the specified procedure, we may ask you to submit supplemental information showing that your alternate procedure is consistently and reliably at least as accurate and repeatable as the specified procedure. (b) We may make our approval under this section conditional upon meeting other requirements or specifications. We may limit our approval, for example, to certain time frames, specific duty cycles, or specific emission standards. Based upon any supplemental information we receive after our initial approval, we may amend a previously approved alternate procedure to extend, limit, or discontinue its use. We intend to publicly announce alternate procedures that we approve. (c) Although we will make every effort to approve only alternate procedures that completely meet our requirements, we may revoke our approval of an alternate procedure if new information shows that it is significantly not equivalent to the specified procedure. If we do this, we will grant time to switch to testing using an allowed procedure, considering the following factors: (1) The cost, difficulty, and availability to switch to a procedure that we allow. (2) The degree to which the alternate procedure affects your ability to show that your engines comply with all applicable emission standards. (3) Any relevant factors considered in our initial approval. (d) If we do not approve your proposed alternate procedure based on the information in your initial request, we may ask you to send additional information to fully evaluate your request. While we consider the information specified in this paragraph (d) and the statistical criteria of paragraph (e) of this section to be sufficient to demonstrate equivalence, it may not be necessary to include all the information or meet the specified statistical criteria. For example, systems that do not meet the statistical criteria in paragraph (e) of this section because they have a small bias toward high emission results could be approved since they would not adversely affect your ability to demonstrate compliance with applicable standards. (1) Theoretical basis. X 2 (2) Technical description. (3) Procedure execution. Summarize the installation, calibration, operation, and maintenance procedures in a step-by-step format. Describe how any calibration is performed using NIST-traceable standards or other similar standards we approve. Calibration must be specified by using known quantities and must not be specified as a comparison with other allowed procedures. (4) Data-collection techniques. (i) Both procedures must be calibrated independently to NIST-traceable standards or to other similar standards we approve. (ii) Include measured emission results from all applicable duty cycles. Measured emission results should show that the test engine meets all applicable emission standards according to specified procedures. (iii) Use statistical methods to evaluate the emission measurements, such as those described in paragraph (e) of this section. (e) Absent any other directions from us, use a t F (1) Repeat measurements for all applicable duty cycles at least seven times for each procedure. You may use laboratory duty cycles to evaluate field-testing procedures. Be sure to include all available results to evaluate the precision and accuracy of the proposed alternate procedure, as described in § 1065.2. (2) Demonstrate the accuracy of the proposed alternate procedure by showing that it passes a two-sided t t (i) For paired data, the population of the paired differences from which you sampled paired differences must be independent. That is, the probability of any given value of one paired difference is unchanged by knowledge of the value of another paired difference. For example, your paired data would violate this requirement if your series of paired differences showed a distinct increase or decrease that was dependent on the time at which they were sampled. (ii) For paired data, the population of paired differences from which you sampled the paired differences must have a normal (i.e., Gaussian) distribution. If the population of paired difference is not normally distributed, consult a statistician for a more appropriate statistical test, which may include transforming the data with a mathematical function or using some kind of non-parametric test. (3) Show that t t t crit (i) 90% for a proposed alternate procedure for laboratory testing. (ii) 95% for a proposed alternate procedure for field testing. (4) Demonstrate the precision of the proposed alternate procedure by showing that it passes an F F (i) Within each set, the values must be independent. That is, the probability of any given value in a set must be unchanged by knowledge of another value in that set. For example, your data would violate this requirement if a set showed a distinct increase or decrease that was dependent upon the time at which they were sampled. (ii) For each set, the population of values from which you sampled must have a normal (i.e., Gaussian) distribution. If the population of values is not normally distributed, consult a statistician for a more appropriate statistical test, which may include transforming the data with a mathematical function or using some kind of non-parametric test. (iii) The two sets must be independent of each other. That is, the probability of any given value in one set must be unchanged by knowledge of another value in the other set. For example, your data would violate this requirement if one value in a set showed a distinct increase or decrease that was dependent upon a value in the other set. Note that a trend of emission changes from an engine would not violate this requirement. (iv) If you collect paired data for the paired t F (5) Show that F F F crit F F F F crit (i) 90% for a proposed alternate procedure for laboratory testing. (ii) 95% for a proposed alternate procedure for field testing. [70 FR 40516, July 13, 2005, as amended at 73 FR 37290, June 30, 2008; 79 FR 23752, Apr. 28, 2014; 88 FR 4670, Jan. 24, 2023; 89 FR 29794, Apr. 22, 2024] § 1065.15 Overview of procedures for laboratory and field testing. This section outlines the procedures to test engines that are subject to emission standards. (a) In the standard-setting part, we set brake-specific emission standards in g/(kW · hr) (or g/(hp · hr)), for the following constituents: (1) Total oxides of nitrogen, NO X (2) Hydrocarbon, HC, which may be expressed in the following ways: (i) Total hydrocarbon, THC. (ii) Nonmethane hydrocarbon, NMHC, which results from subtracting methane, CH 4 (iii) Nonmethane-nonethane hydrocarbon, NMNEHC, which results from subtracting methane, CH 4 2 6 (iv) Total hydrocarbon-equivalent, THCE, which results from adjusting THC mathematically to be equivalent on a carbon-mass basis. (v) Nonmethane hydrocarbon-equivalent, NMHCE, which results from adjusting NMHC mathematically to be equivalent on a carbon-mass basis. (3) Particulate matter, PM. (4) Carbon monoxide, CO. (5) Carbon dioxide, CO 2 (6) Methane, CH 4 (7) Nitrous oxide, N 2 (b) Note that some engines are not subject to standards for all the emission constituents identified in paragraph (a) of this section. Note also that the standard-setting part may include standards for pollutants not listed in paragraph (a) of this section. (c) We generally set brake-specific emission standards over test intervals and/or duty cycles, as follows: (1) Engine operation. (2) Constituent determination. (i) Continuous sampling. (ii) Batch sampling. X 2 4 2 2 (iii) Combined sampling. (A) You may use continuous sampling for some constituents and batch sampling for others. (B) You may use continuous and batch sampling for a single constituent, with one being a redundant measurement. See (3) Work determination. (i) Speed and torque. (ii) Fuel consumed and brake-specific fuel consumption. (d) Refer to § 1065.650 for calculations to determine brake-specific emissions. (e) The following figure illustrates the allowed measurement configurations described in this part 1065: (f) This part 1065 describes how to test engines in a laboratory-type environment or in the field. (1) This affects test intervals and duty cycles as follows: (i) For laboratory testing, you generally determine brake-specific emissions for duty-cycle testing by using an engine dynamometer in a laboratory or other environment. This typically consists of one or more test intervals, each defined by a duty cycle, which is a sequence of modes, speeds, and/or torques (or powers) that an engine must follow. If the standard-setting part allows it, you may also simulate field testing with an engine dynamometer in a laboratory or other environment. (ii) Field testing consists of normal in-use engine operation while an engine is installed in a vehicle, equipment, or vessel rather than following a specific engine duty cycle. The standard-setting part specifies how test intervals are defined for field testing. (2) The type of testing may also affect what test equipment may be used. You may use “lab-grade” test equipment for any testing. The term “lab-grade” refers to equipment that fully conforms to the applicable specifications of this part. For some testing you may alternatively use “field-grade” equipment. The term “field-grade” refers to equipment that fully conforms to the applicable specifications of subpart J of this part, but does not fully conform to other specifications of this part. You may use “field-grade” equipment for field testing. We also specify in this part and in the standard-setting parts certain cases in which you may use “field-grade” equipment for testing in a laboratory-type environment. ( Note: [70 FR 40516, July 13, 2005, as amended at 73 FR 37290, June 30, 2008; 75 FR 23028, Apr. 30, 2010; 76 FR 57437, Sept. 15, 2011; 79 FR 23753, Apr. 28, 2014; 81 FR 74162, Oct. 25, 2016] § 1065.20 Units of measure and overview of calculations. (a) System of units. (1) We designate angular speed, f n (2) We designate brake-specific emissions in grams per kilowatt-hour (g/(kW · hr)), rather than the SI unit of grams per megajoule (g/MJ). In addition, we use the symbol hr to identify hour, rather than the SI convention of using h. This is based on the fact that engines are generally subject to emission standards expressed in g/kW · hr. If we specify engine standards in grams per horsepower · hour (g/(hp · hr)) in the standard-setting part, convert units as specified in paragraph (d) of this section. (3) We generally designate temperatures in units of degrees Celsius ( °C) unless a calculation requires an absolute temperature. In that case, we designate temperatures in units of Kelvin (K). For conversion purposes throughout this part, 0 °C equals 273.15 K. Unless specified otherwise, always use absolute temperature values for multiplying or dividing by temperature. (b) Concentrations. (1) For ideal gases, µmol/mol, formerly ppm (volume). (2) For all substances, cm 3 3 (3) For all substances, mg/kg, formerly ppm (mass). (c) Absolute pressure. (d) Units conversion. (1) Testing. (2) Humidity. (3) Emission standards. (e) Rounding. (1) If the first (left-most) digit to be removed is less than five, remove all the appropriate digits without changing the digits that remain. For example, 3.141593 rounded to the second decimal place is 3.14. (2) If the first digit to be removed is greater than five, remove all the appropriate digits and increase the lowest-value remaining digit by one. For example, 3.141593 rounded to the fourth decimal place is 3.1416. (3) If the first digit to be removed is five with at least one additional non-zero digit following the five, remove all the appropriate digits and increase the lowest-value remaining digit by one. For example, 3.141593 rounded to the third decimal place is 3.142. (4) If the first digit to be removed is five with no additional non-zero digits following the five, remove all the appropriate digits, increase the lowest-value remaining digit by one if it is odd and leave it unchanged if it is even. For example, 1.75 and 1.750 rounded to the first decimal place are 1.8; while 1.85 and 1.850 rounded to the first decimal place are also 1.8. Note that this rounding procedure will always result in an even number for the lowest-value digit. (5) This paragraph (e)(5) applies if the regulation specifies rounding to an increment other than decimal places or powers of ten (to the nearest 0.01, 0.1, 1, 10, 100, etc. (6) The following tables further illustrate the rounding procedures specified in this paragraph (e): Quantity Rounding increment 10 1 0.1 0.01 3.141593 0 3 3.1 3.14 123,456.789 123,460 123,457 123,456.8 123,456.79 5.500 10 6 5.5 5.50 4.500 0 4 4.5 4.50 Quantity Rounding increment 25 3 0.5 0.02 229.267 225 228 229.5 229.26 62.500 50 63 62.5 62.50 87.500 100 87 87.5 87.50 7.500 0 6 7.5 7.50 (7) This paragraph (e)(7) applies where we specify a limit or tolerance as some percentage of another value (such as ±2% of a maximum concentration). You may show compliance with such specifications either by applying the percentage to the total value to calculate an absolute limit, or by converting the absolute value to a percentage by dividing it by the total value. (i) Do not round either value (the absolute limit or the calculated percentage), except as specified in paragraph (e)(7)(ii) of this section. For example, assume we specify that an analyzer must have a repeatability of ±1% of the maximum concentration or better, the maximum concentration is 1059 ppm, and you determine repeatability to be ±6.3 ppm. In this example, you could calculate an absolute limit of ±10.59 ppm (1059 ppm × 0.01) or calculate that the 6.3 ppm repeatability is equivalent to a repeatability of 0.5949008498584%. (ii) Prior to July 1, 2013, you may treat tolerances (and equivalent specifications) specified in percentages as having fixed rather than infinite precision. For example, 2% would be equivalent to 1.51% to 2.50% and 2.0% would be equivalent to 1.951% to 2.050%. Note that this allowance applies whether or not the percentage is explicitly specified as a percentage of another value. (8) You may use measurement devices that incorporate internal rounding, consistent with the provisions of this paragraph (e)(8). You may use devices that use any rounding convention if they report six or more significant digits. You may use devices that report fewer than six digits, consistent with good engineering judgment and the accuracy, repeatability, and noise specifications of this part. Note that this provision does not necessarily require you to perform engineering analysis or keep records. (f) Interpretation of ranges. Interpret a range as a tolerance unless we explicitly identify it as an accuracy, repeatability, linearity, or noise specification. See § 1065.1001 for the definition of tolerance. In this part, we specify two types of ranges: (1) Whenever we specify a range by a single value and corresponding limit values above and below that value (such as X ±Y), target the associated control point to that single value (X). Examples of this type of range include “±10% of maximum pressure”, or “(30 ±10) kPa”. In these examples, you would target the maximum pressure or 30 kPa, respectively. (2) Whenever we specify a range by the interval between two values, you may target any associated control point to any value within that range. An example of this type of range is “(40 to 50) kPa”. (g) Scaling of specifications with respect to an applicable standard. [70 FR 40516, July 13, 2005, as amended at 73 FR 37292, June 30, 2008; 76 FR 57438, Sept. 15, 2011; 79 FR 23753, Apr. 28, 2014] § 1065.25 Recordkeeping. (a) The procedures in this part include various requirements to record data or other information. Refer to the standard-setting part and § 1065.695 regarding specific recordkeeping requirements. (b) You must promptly send us organized, written records in English if we ask for them. We may review them at any time. (c) We may waive specific reporting or recordkeeping requirements we determine to be unnecessary for the purposes of this part and the standard-setting part. Note that while we will generally keep the records required by this part, we are not obligated to keep records we determine to be unnecessary for us to keep. For example, while we require you to keep records for invalid tests so that we may verify that your invalidation was appropriate, it is not necessary for us to keep records for our own invalid tests. [79 FR 23753, Apr. 28, 2014] Subpart B—Equipment Specifications § 1065.101 Overview. (a) This subpart specifies equipment, other than measurement instruments, related to emission testing. The provisions of this subpart apply for all engine dynamometer testing where engine speeds and loads are controlled to follow a prescribed duty cycle. See subpart J of this part to determine which of the provisions of this subpart apply for field testing. This equipment includes three broad categories-dynamometers, engine fluid systems (such as fuel and intake-air systems), and emission-sampling hardware. (b) Other related subparts in this part identify measurement instruments (subpart C), describe how to evaluate the performance of these instruments (subpart D), and specify engine fluids and analytical gases (subpart H). (c) Subpart J of this part describes additional equipment that is specific to field testing. (d) Figures 1 and 2 of this section illustrate some of the possible configurations of laboratory equipment. These figures are schematics only; we do not require exact conformance to them. Figure 1 of this section illustrates the equipment specified in this subpart and gives some references to sections in this subpart. Figure 2 of this section illustrates some of the possible configurations of a full-flow dilution, constant-volume sampling (CVS) system. Not all possible CVS configurations are shown. (e) Dynamometer testing involves engine operation over speeds and loads that are controlled to a prescribed duty cycle. Field testing involves measuring emissions over normal in-use operation of a vehicle or piece of equipment. Field testing does not involve operating an engine over a prescribed duty cycle. [70 FR 40516, July 13, 2005, as amended at 73 FR 37292, June 30, 2008] § 1065.110 Work inputs and outputs, accessory work, and operator demand. (a) Work. (1) Shaft work. (i) You may use eddy-current and water-brake dynamometers for any testing that does not involve engine motoring, which is identified by negative torque commands in a reference duty cycle. See the standard setting part for reference duty cycles that are applicable to your engine. (ii) You may use alternating-current or direct-current motoring dynamometers for any type of testing. (iii) You may use one or more dynamometers. (iv) You may use any device that is already installed on a vehicle, equipment, or vessel to absorb work from the engine's output shaft(s). Examples of these types of devices include a vessel's propeller and a locomotive's generator. (2) Electrical work. (i) Use storage batteries or capacitors that are of the type and capacity installed in use. (ii) Use motors, generators, and alternators that are of the type and capacity installed in use. (iii) Use a resistor load bank to simulate electrical loads. (3) Pump, compressor, and turbine work. (b) Laboratory work inputs. (c) Engine accessories. (d) Engine starter. (e) Operator demand for shaft work. (f) Other engine inputs. [70 FR 40516, July 13, 2005, as amended at 73 FR 37292, June 30, 2008] § 1065.120 Fuel properties and fuel temperature and pressure. (a) Use fuels as specified in the standard-setting part, or as specified in subpart H of this part if fuels are not specified in the standard-setting part. (b) If the engine manufacturer specifies fuel temperature and pressure tolerances and the location where they are to be measured, then measure the fuel temperature and pressure at the specified location to show that you are within these tolerances throughout testing. (c) If the engine manufacturer does not specify fuel temperature and pressure tolerances, use good engineering judgment to set and control fuel temperature and pressure in a way that represents typical in-use fuel temperatures and pressures. [70 FR 40516, July 13, 2005, as amended at 73 FR 37293, June 30, 2008] § 1065.122 Engine cooling and lubrication. (a) Engine cooling. (1) For air-cooled engines only, if you use auxiliary fans you must account for work input to the fan(s) according to § 1065.110. (2) See § 1065.125 for more information related to intake-air cooling. (3) See § 1065.127 for more information related to exhaust gas recirculation cooling. (4) Measure temperatures at the manufacturer-specified locations. If the manufacturer does not specify temperature measurement locations, then use good engineering judgment to monitor intake-air, oil, coolant, block, and head temperatures to ensure that they are in their expected ranges for normal operation. (b) Forced cooldown. (c) Lubricating oil. (d) Coolant. [70 FR 40516, July 13, 2005, as amended at 73 FR 37293, June 30, 2008] § 1065.125 Engine intake air. (a) Use the intake-air system installed on the engine or one that represents a typical in-use configuration. This includes the charge-air cooling and exhaust gas recirculation systems. (b) Measure temperature, humidity, and atmospheric pressure near the entrance of the furthest upstream engine or in-use intake system component. This would generally be near the engine's air filter, or near the inlet to the in-use air intake system for engines that have no air filter. For engines with multiple intakes, make measurements near the entrance of each intake. (1) Pressure. (2) Humidity. X (3) Temperature. (c) Maintain the temperature of intake air to (25 ±5) °C, except as follows: (1) Follow the standard-setting part if it specifies different temperatures. (2) For engines above 560 kW, you may use 35 °C as the upper bound of the tolerance. However, your system must be capable of controlling the temperature to the 25 °C setpoint for any steady-state operation at >30% of maximum engine power. (3) You may ask us to allow you to apply a different setpoint for intake air temperature if it is necessary to remain consistent with the provisions of § 1065.10(c)(1) for testing during which ambient temperature will be outside this range. (d) Use an intake-air restriction that represents production engines. Make sure the intake-air restriction is between the manufacturer's specified maximum for a clean filter and the manufacturer's specified maximum allowed. Measure the static differential pressure of the restriction at the location and at the speed and torque set points specified by the manufacturer. If the manufacturer does not specify a location, measure this pressure upstream of any turbocharger or exhaust gas recirculation system connection to the intake air system. If the manufacturer does not specify speed and torque points, measure this pressure while the engine outputs maximum power. As the manufacturer, you are liable for emission compliance for all values up to the maximum restriction you specify for a particular engine. (e) This paragraph (e) includes provisions for simulating charge-air cooling in the laboratory. This approach is described in paragraph (e)(1) of this section. Limits on using this approach are described in paragraphs (e)(2) and (3) of this section. (1) Use a charge-air cooling system with a total intake-air capacity that represents production engines' in-use installation. Design any laboratory charge-air cooling system to minimize accumulation of condensate. Drain any accumulated condensate. Before starting a duty cycle (or preconditioning for a duty cycle), completely close all drains that would normally be closed during in-use operation. Keep those drains closed during the emission test. Maintain coolant conditions as follows: (i) Maintain a coolant temperature of at least 20 °C at the inlet to the charge-air cooler throughout testing. We recommend maintaining a coolant temperature of 25 ±5 °C at the inlet of the charge-air cooler. (ii) At the engine conditions specified by the manufacturer, set the coolant flow rate to achieve an air temperature within ±5 °C of the value specified by the manufacturer after the charge-air cooler's outlet. Measure the air-outlet temperature at the location specified by the manufacturer. Use this coolant flow rate set point throughout testing. If the engine manufacturer does not specify engine conditions or the corresponding charge-air cooler air outlet temperature, set the coolant flow rate at maximum engine power to achieve a charge-air cooler air outlet temperature that represents in-use operation. (iii) If the engine manufacturer specifies pressure-drop limits across the charge-air cooling system, ensure that the pressure drop across the charge-air cooling system at engine conditions specified by the manufacturer is within the manufacturer's specified limit(s). Measure the pressure drop at the manufacturer's specified locations. (2) Using a constant flow rate as described in paragraph (e)(1) of this section may result in unrepresentative overcooling of the intake air. The provisions of this paragraph (e)(2) apply instead of the provisions of § 1065.10(c)(1) for this simulation. Our allowance to cool intake air as specified in this paragraph (e) does not affect your liability for field testing or for laboratory testing that is done in a way that better represents in-use operation. Where we determine that this allowance adversely affects your ability to demonstrate that your engines would comply with emission standards under in-use conditions, we may require you to use more sophisticated setpoints and controls of charge-air pressure drop, coolant temperature, and flow rate to achieve more representative results. (3) This approach does not apply for field testing. You may not correct measured emission levels from field testing to account for any differences caused by the simulated cooling in the laboratory. [70 FR 40516, July 13, 2005, as amended at 73 FR 37293, June 30, 2008; 73 FR 59321, Oct. 8, 2008; 75 FR 23029, Apr. 30, 2010; 76 FR 57440, Sept. 15, 2011] § 1065.127 Exhaust gas recirculation. Use the exhaust gas recirculation (EGR) system installed with the engine or one that represents a typical in-use configuration. This includes any applicable EGR cooling devices. § 1065.130 Engine exhaust. (a) General. (b) Aftertreatment configuration. (1) Position any aftertreatment device so its distance from the nearest exhaust manifold flange or turbocharger outlet is within the range specified by the engine manufacturer in the application for certification. If this distance is not specified, position aftertreatment devices to represent typical in-use vehicle configurations. (2) You may use exhaust tubing that is not from the in-use exhaust system upstream of any aftertreatment device that is of diameter(s) typical of in-use configurations. If you use exhaust tubing that is not from the in-use exhaust system upstream of any aftertreatment device, position each aftertreatment device according to paragraph (b)(1) of this section. (c) Sampling system connections. (1) Minimize laboratory exhaust tubing lengths and use a total length of laboratory tubing of no more than 10 m or 50 outside diameters, whichever is greater. The start of laboratory exhaust tubing should be specified as the exit of the exhaust manifold, turbocharger outlet, last aftertreatment device, or the in-use exhaust system, whichever is furthest downstream. The end of laboratory exhaust tubing should be specified as the sample point, or first point of dilution. If laboratory exhaust tubing consists of several different outside tubing diameters, count the number of diameters of length of each individual diameter, then sum all the diameters to determine the total length of exhaust tubing in diameters. Use the mean outside diameter of any converging or diverging sections of tubing. Use outside hydraulic diameters of any noncircular sections. For multiple stack configurations where all the exhaust stacks are combined, the start of the laboratory exhaust tubing may be taken at the last joint of where all the stacks are combined. (2) You may install short sections of flexible laboratory exhaust tubing at any location in the engine or laboratory exhaust systems. You may use up to a combined total of 2 m or 10 outside diameters of flexible exhaust tubing. (3) Insulate any laboratory exhaust tubing downstream of the first 25 outside diameters of length. (4) Use laboratory exhaust tubing materials that are smooth-walled, electrically conductive, and not reactive with exhaust constituents. Stainless steel is an acceptable material. (5) We recommend that you use laboratory exhaust tubing that has either a wall thickness of less than 2 mm or is air gap-insulated to minimize temperature differences between the wall and the exhaust. (6) We recommend that you connect multiple exhaust stacks from a single engine into one stack upstream of any emission sampling. For raw or dilute partial-flow emission sampling, to ensure mixing of the multiple exhaust streams before emission sampling, we recommend a minimum Reynolds number, Re # Re # Re # Re # Re # (d) In-line instruments. (e) Leaks (f) Grounding. (g) Forced cooldown. (h) Exhaust restriction. (i) Open crankcase emissions. (1) Use laboratory tubing materials that are smooth-walled, electrically conductive, and not reactive with crankcase emissions. Stainless steel is an acceptable material. Minimize tube lengths. We also recommend using heated or thin-walled or air gap-insulated tubing to minimize temperature differences between the wall and the crankcase emission constituents. (2) Minimize the number of bends in the laboratory crankcase tubing and maximize the radius of any unavoidable bend. (3) Use laboratory crankcase exhaust tubing that meets the engine manufacturer's specifications for crankcase back pressure. (4) Connect the crankcase exhaust tubing into the raw exhaust downstream of any aftertreatment system, downstream of any installed exhaust restriction, and sufficiently upstream of any sample probes to ensure complete mixing with the engine's exhaust before sampling. Extend the crankcase exhaust tube into the free stream of exhaust to avoid boundary-layer effects and to promote mixing. You may orient the crankcase exhaust tube's outlet in any direction relative to the raw exhaust flow. [73 FR 37293, June 30, 2008, as amended at 79 FR 23754, Apr. 28, 2014; 86 FR 34534, June 29, 2021] § 1065.140 Dilution for gaseous and PM constituents. (a) General. (b) Dilution-air conditions and background concentrations. (1) You may measure constituent concentrations in the dilution air and compensate for background effects on test results. See § 1065.650 for calculations that compensate for background concentrations (40 CFR 1066.610 for vehicle testing). (2) Measure these background concentrations the same way you measure diluted exhaust constituents, or measure them in a way that does not affect your ability to demonstrate compliance with the applicable standards in this chapter. For example, you may use the following simplifications for background sampling: (i) You may disregard any proportional sampling requirements. (ii) You may use unheated gaseous sampling systems. (iii) You may use unheated PM sampling systems. (iv) You may use continuous sampling if you use batch sampling for diluted emissions. (v) You may use batch sampling if you use continuous sampling for diluted emissions. (3) For removing background PM, we recommend that you filter all dilution air, including primary full-flow dilution air, with high-efficiency particulate air (HEPA) filters that have an initial minimum collection efficiency specification of 99.97% (see § 1065.1001 for procedures related to HEPA-filtration efficiencies). Ensure that HEPA filters are installed properly so that background PM does not leak past the HEPA filters. If you choose to correct for background PM without using HEPA filtration, demonstrate that the background PM in the dilution air contributes less than 50% to the net PM collected on the sample filter. You may correct net PM without restriction if you use HEPA filtration. (c) Full-flow dilution; constant-volume sampling (CVS). (1) Construction. (2) Pressure control. (3) Mixing. Re # Re # Re # (4) Flow measurement preconditioning. (i) You may use flow straighteners, pulsation dampeners, or both of these. (ii) You may use a filter. (iii) You may use a heat exchanger to control the temperature upstream of any flow meter, but you must take steps to prevent aqueous condensation as described in paragraph (c)(6) of this section. (5) Flow measurement. (6) Aqueous condensation. (i) Preventing aqueous condensation (ii) Limiting aqueous condensation. (A) Use chemical balance equations in § 1065.655 to calculate the mole fraction of water in the dilute exhaust continuously during testing. Alternatively, you may continuously measure the mole fraction of water in the dilute exhaust prior to any condensation during testing. Use good engineering judgment to select, calibrate and verify water analyzers/detectors. The linearity verification requirements of § 1065.307 do not apply to water analyzers/detectors used to correct for the water content in exhaust samples. (B) Use good engineering judgment to select and monitor locations on the CVS tunnel walls prior to the last emission sample probe. If you are also verifying limited condensation from the last emission sample probe to the CVS flow meter, use good engineering judgment to select and monitor locations on the CVS tunnel walls, optional CVS heat exchanger, and CVS flow meter. For optional CVS heat exchangers, you may use the lowest water temperature at the inlet(s) and outlet(s) to determine the minimum internal surface temperature. Identify the minimum surface temperature on a continuous basis. (C) Identify the maximum potential mole fraction of dilute exhaust lost on a continuous basis during the entire test interval. This value must be less than or equal to 0.02. Calculate on a continuous basis the mole fraction of water that would be in equilibrium with liquid water at the measured minimum surface temperature. Subtract this mole fraction from the mole fraction of water that would be in the exhaust without condensation (either measured or from the chemical balance), and set any negative values to zero. This difference is the potential mole fraction of the dilute exhaust that would be lost due to water condensation on a continuous basis. (D) Integrate the product of the molar flow rate of the dilute exhaust and the potential mole fraction of dilute exhaust lost, and divide by the totalized dilute exhaust molar flow over the test interval. This is the potential mole fraction of the dilute exhaust that would be lost due to water condensation over the entire test interval. Note that this assumes no re-evaporation. This value must be less than or equal to 0.005. (7) Flow compensation. (d) Partial-flow dilution (PFD). (1) Applicability. (ii) You may use PFD to extract a proportional raw exhaust sample for any batch or continuous gaseous emission sampling over any transient duty cycle, any steady-state duty cycle, or any ramped-modal cycle. (iii) You may use PFD to extract a proportional raw exhaust sample for any batch or continuous field-testing. (iv) You may use PFD to extract a proportional diluted exhaust sample from a CVS for any batch or continuous emission sampling. (v) You may use PFD to extract a constant raw or diluted exhaust sample for any continuous emission sampling. (vi) You may use PFD to extract a constant raw or diluted exhaust sample for any steady-state emission sampling. (2) Constant dilution-ratio PFD. (i) Dilute an already proportional flow. For example, you may do this as a way of performing secondary dilution from a CVS tunnel to achieve overall dilution ratio for PM sampling. (ii) Continuously measure constituent concentrations. For example, you might dilute to precondition a sample of raw exhaust to control its temperature, humidity, or constituent concentrations upstream of continuous analyzers. In this case, you must take into account the dilution ratio before multiplying the continuous concentration by the sampled exhaust flow rate. (iii) Extract a proportional sample from a separate constant dilution ratio PFD system. For example, you might use a variable-flow pump to proportionally fill a gaseous storage medium such as a bag from a PFD system. In this case, the proportional sampling must meet the same specifications as varying dilution ratio PFD in paragraph (d)(3) of this section. (iv) For each mode of a discrete-mode test (such as a locomotive notch setting or a specific setting for speed and torque), use a constant dilution ratio for any PM sampling. You must change the overall PM sampling system dilution ratio between modes so that the dilution ratio on the mode with the highest exhaust flow rate meets § 1065.140(e)(2) and the dilution ratios on all other modes is higher than this (minimum) dilution ratio by the ratio of the maximum exhaust flow rate to the exhaust flow rate of the corresponding other mode. This is the same dilution ratio requirement for RMC or field transient testing. You must account for this change in dilution ratio in your emission calculations. (3) Varying dilution-ratio PFD. (i) Use a control system with sensors and actuators that can maintain proportional sampling over intervals as short as 200 ms (i.e., 5 Hz control). (ii) For control input, you may use any sensor output from one or more measurements; for example, intake-air flow, fuel flow, exhaust flow, engine speed, and intake manifold temperature and pressure. (iii) Account for any emission transit time in the PFD system, as necessary. (iv) You may use preprogrammed data if they have been determined for the specific test site, duty cycle, and test engine from which you dilute emissions. (v) We recommend that you run practice cycles to meet the verification criteria in § 1065.545. Note that you must verify every emission test by meeting the verification criteria with the data from that specific test. Data from previously verified practice cycles or other tests may not be used to verify a different emission test. (vi) You may not use a PFD system that requires preparatory tuning or calibration with a CVS or with the emission results from a CVS. Rather, you must be able to independently calibrate the PFD. (e) Dilution air temperature, dilution ratio, residence time, and temperature control of PM samples. (1) Set the dilution air temperature to (25 ±5) °C. Use good engineering judgment to select a location to measure this temperature that is as close as practical upstream of the point where dilution air mixes with raw exhaust. (2) For any PM dilution system ( i.e., (3) Configure any PM dilution system to have an overall residence time of (1.0 to 5.5) s, as measured from the location of initial dilution air introduction to the location where PM is collected on the sample media. Also configure the system to have a residence time of at least 0.50 s, as measured from the location of final dilution air introduction to the location where PM is collected on the sample media. When determining residence times within sampling system volumes, use an assumed flow temperature of 25 °C and pressure of 101.325 kPa. (4) Control sample temperature to a (47 ±5) °C tolerance, as measured anywhere within 20 cm upstream or downstream of the PM storage media (such as a filter). You may instead measure sample temperature up to 30 cm upstream of the filter or other PM storage media if it is housed within a chamber with temperature controlled to stay within the specified temperature range. Measure sample temperature with a bare-wire junction thermocouple with wires that are (0.500 ±0.025) mm diameter, or with another suitable instrument that has equivalent performance. [79 FR 23754, Apr. 28, 2014, as amended at 81 FR 74162, Oct. 25, 2016; 86 FR 34534, June 29, 2021; 88 FR 4670, Jan. 24, 2023] § 1065.145 Gaseous and PM probes, transfer lines, and sampling system components. (a) Continuous and batch sampling. (b) Options for engines with multiple exhaust stacks. (1) Route the exhaust flow from the multiple stacks into a single flow as described in § 1065.130(c)(6). Sample and measure emissions after the exhaust streams are mixed. Calculate the emissions as a single sample from the entire engine. We recommend this as the preferred option, since it requires only a single measurement and calculation of the exhaust molar flow for the entire engine. (2) Sample and measure emissions from each stack and calculate emissions separately for each stack. Add the mass (or mass rate) emissions from each stack to calculate the emissions from the entire engine. Testing under this paragraph (b)(2) requires measuring or calculating the exhaust molar flow for each stack separately. If the exhaust molar flow in each stack cannot be calculated from intake air flow(s), fuel flow(s), and measured gaseous emissions, and it is impractical to measure the exhaust molar flows directly, you may alternatively proportion the engine's calculated total exhaust molar flow rate (where the flow is calculated using intake air mass flow(s), fuel mass flow(s), and emissions concentrations) based on exhaust molar flow measurements in each stack using a less accurate, non-traceable method. For example, you may use a total pressure probe and static pressure measurement in each stack. (3) Sample and measure emissions from one stack and repeat the duty cycle as needed to collect emissions from each stack separately. Calculate the emissions from each stack and add the separate measurements to calculate the mass (or mass rate) emissions from the entire engine. Testing under this paragraph (b)(3) requires measuring or calculating the exhaust molar flow for each stack separately. You may alternatively proportion the engine's calculated total exhaust molar flow rate based on calculation and measurement limitations as described in paragraph (b)(2) of this section. Use the average of the engine's total power or work values from the multiple test runs to calculate brake-specific emissions. Divide the total mass (or mass rate) of each emission by the average power (or work). You may alternatively use the engine power or work associated with the corresponding stack during each test run if these values can be determined for each stack separately. (4) Sample and measure emissions from each stack separately and calculate emissions for the entire engine based on the stack with the highest concentration. Testing under this paragraph (b)(4) requires only a single exhaust flow measurement or calculation for the entire engine. You may determine which stack has the highest concentration by performing multiple test runs, reviewing the results of earlier tests, or using good engineering judgment. Note that the highest concentration of different pollutants may occur in different stacks. Note also that the stack with the highest concentration of a pollutant during a test interval for field testing may be a different stack than the one you identified based on average concentrations over a duty cycle. (5) Sample emissions from each stack separately and combine the wet sample streams from each stack proportionally to the exhaust molar flows in each stack. Measure the emission concentrations and calculate the emissions for the entire engine based on these weighted concentrations. Testing under this paragraph (b)(5) requires measuring or calculating the exhaust molar flow for each stack separately during the test run to proportion the sample streams from each stack. If it is impractical to measure the exhaust molar flows directly, you may alternatively proportion the wet sample streams based on less accurate, non-traceable flow methods. For example, you may use a total pressure probe and static pressure measurement in each stack. The following restrictions apply for testing under this paragraph (b)(5): (i) You must use an accurate, traceable measurement or calculation of the engine's total exhaust molar flow rate for calculating the mass of emissions from the entire engine. (ii) You may dry the single, combined, proportional sample stream; you may not dry the sample streams from each stack separately. (iii) You must measure and proportion the sample flows from each stack with active flow controls. For PM sampling, you must measure and proportion the diluted sample flows from each stack with active flow controls that use only smooth walls with no sudden change in cross-sectional area. For example, you may control the dilute exhaust PM sample flows using electrically conductive vinyl tubing and a control device that pinches the tube over a long enough transition length so no flow separation occurs. (iv) For PM sampling, the transfer lines from each stack must be joined so the angle of the joining flows is 12.5° or less. Note that the exhaust manifold must meet the same specifications as the transfer line according to paragraph (d) of this section. (6) Sample emissions from each stack separately and combine the wet sample streams from each stack equally. Measure the emission concentrations and calculate the emissions for the entire engine based on these measured concentrations. Testing under this paragraph (b)(6) assumes that the raw-exhaust and sample flows are the same for each stack. The following restrictions apply for testing under this paragraph (b)(6): (i) You must measure and demonstrate that the sample flow from each stack is within 5% of the value from the stack with the highest sample flow. You may alternatively ensure that the stacks have equal flow rates without measuring sample flows by designing a passive sampling system that meets the following requirements: (A) The probes and transfer line branches must be symmetrical, have equal lengths and diameters, have the same number of bends, and have no filters. (B) If probes are designed such that they are sensitive to stack velocity, the stack velocity must be similar at each probe. For example, a static pressure probe used for gaseous sampling is not sensitive to stack velocity. (C) The stack static pressure must be the same at each probe. You can meet this requirement by placing probes at the end of stacks that are vented to atmosphere. (D) For PM sampling, the transfer lines from each stack must be joined so the angle of the joining flows is 12.5° or less. Note that the exhaust manifold must meet the same specifications as the transfer line according to paragraph (d) of this section. (ii) You may use the procedure in this paragraph (b)(6) only if you perform an analysis showing that the resulting error due to imbalanced stack flows and concentrations is either at or below 2%. You may alternatively show that the resulting error does not impact your ability to demonstrate compliance with applicable standards. For example, you may use less accurate, non-traceable measurements of emission concentrations and molar flow in each stack and demonstrate that the imbalances in flows and concentrations cause 2% or less error. (iii) For a two-stack engine, you may use the procedure in this paragraph (b)(6) only if you can show that the stack with the higher flow has the lower average concentration for each pollutant over the duty cycle. (iv) You must use an accurate, traceable measurement or calculation of the engine's total exhaust molar flow rate for calculating the mass of emissions from the entire engine. (v) You may dry the single, equally combined, sample stream; you may not dry the sample streams from each stack separately. (vi) You may determine your exhaust flow rates with a chemical balance of exhaust gas concentrations and either intake air flow or fuel flow. (c) Gaseous and PM sample probes. (1) Probe design and construction. (2) Gaseous sample probes. (i) For probes that extract NO X (ii) For probes that extract hydrocarbons for THC or NMHC analysis from the diluted exhaust of compression-ignition engines, two-stroke spark-ignition engines, or four-stroke spark-ignition engines at or below 19 kW, we recommend heating the probe to minimize hydrocarbon contamination consistent with good engineering judgment. If you routinely fail the contamination check in the 1065.520 pretest check, we recommend heating the probe section to approximately 190 °C to minimize contamination. (3) PM sample probes. (d) Transfer lines. (1) Gaseous samples. TM (i) For NO X 2 (ii) For THC transfer lines for testing compression-ignition engines, two-stroke spark-ignition engines, or four-stroke spark-ignition engines at or below 19 kW, maintain a wall temperature tolerance throughout the entire line of (191 ±11) °C. If you sample from raw exhaust, you may connect an unheated, insulated transfer line directly to a probe. Design the length and insulation of the transfer line to cool the highest expected raw exhaust temperature to no lower than 191 °C, as measured at the transfer line's outlet. For dilute sampling, you may use a transition zone between the probe and transfer line of up to 92 cm to allow your wall temperature to transition to (191 ±11) °C. (2) PM samples. (e) Optional sample-conditioning components for gaseous sampling. (1) NO 2 -to-NO converter. 2 X (2) Sample dryer. (i) Osmotic-membrane. T dew p total T dew p total p total (ii) Thermal chiller. 2 2 2 T dew p total T dew p total T dew T chiller T chiller T dew p total (3) Sample pumps. (i) If you use a NO X 2 (ii) For testing compression-ignition engines, two-stroke spark-ignition engines, or four-stroke spark-ignition engines at or below 19 kW, if you use a THC sample pump upstream of a THC analyzer or storage medium, its inner surfaces must be heated to a tolerance of (191 ±11) °C. (4) Ammonia Scrubber. 3 2 (f) Optional sample-conditioning components for PM sampling. (1) PM preclassifier. (2) Other components. [75 FR 23030, Apr. 30, 2010; 79 FR 23756, Apr. 28, 2014; 86 FR 34534, June 29, 2021; 88 FR 4670, Jan. 24, 2023] § 1065.150 Continuous sampling. You may use continuous sampling techniques for measurements that involve raw or dilute sampling. Make sure continuous sampling systems meet the specifications in § 1065.145. Make sure continuous analyzers meet the specifications in subparts C and D of this part. § 1065.170 Batch sampling for gaseous and PM constituents. Batch sampling involves collecting and storing emissions for later analysis. Examples of batch sampling include collecting and storing gaseous emissions in a bag or collecting and storing PM on a filter. You may use batch sampling to store emissions that have been diluted at least once in some way, such as with CVS, PFD, or BMD. You may use batch sampling to store undiluted emissions. You may stop emission sampling anytime the engine is turned off, consistent with good engineering judgment. This is intended to allow for higher concentrations of dilute exhaust gases and more accurate measurements. Account for exhaust transport delay in the sampling system and integrate over the actual sampling duration when determining n dexh (a) Sampling methods. If you extract from a constant-volume flow rate, sample at a constant-volume flow rate as follows: (1) Verify proportional sampling after an emission test as described in § 1065.545. You must exclude from the proportional sampling verification any portion of the test where you are not sampling emissions because the engine is turned off and the batch samplers are not sampling, accounting for exhaust transport delay in the sampling system. Use good engineering judgment to select storage media that will not significantly change measured emission levels (either up or down). For example, do not use sample bags for storing emissions if the bags are permeable with respect to emissions or if they off gas emissions to the extent that it affects your ability to demonstrate compliance with the applicable gaseous emission standards in this chapter. As another example, do not use PM filters that irreversibly absorb or adsorb gases to the extent that it affects your ability to demonstrate compliance with the applicable PM emission standards in this chapter. (2) You must follow the requirements in § 1065.140(e)(2) related to PM dilution ratios. For each filter, if you expect the net PM mass on the filter to exceed 400 µg, assuming a 38 mm diameter filter stain area, you may take the following actions in sequence: (i) For discrete-mode testing only, you may reduce sample time as needed to target a filter loading of 400 µg, but not below the minimum sample time specified in the standard-setting part. (ii) Reduce filter face velocity as needed to target a filter loading of 400 µg, down to 50 cm/s or less. (iii) Increase overall dilution ratio above the values specified in § 1065.140(e)(2) to target a filter loading of 400 µg. (b) Gaseous sample storage media. (1) Up to 40 °C for Tedlar TM TM (2) (191 ±11) °C for Teflon TM Table 1 of § 1065.170—Container Materials for Gaseous Batch Sampling Emissions Engine type Compression-ignition All other engines CO, CO 2 2 4 2 6 3 8 2 2 Tedlar TM TM TM Tedlar TM TM TM THC, NMHC Teflon TM Tedlar TM TM TM (c) PM sample media. (1) If you use filter-based sampling media to extract and store PM for measurement, your procedure must meet the following specifications: (i) If you expect that a filter's total surface concentration of PM will exceed 400 µg, assuming a 38 mm diameter filter stain area, for a given test interval, you may use filter media with a minimum initial collection efficiency of 98%; otherwise you must use a filter media with a minimum initial collection efficiency of 99.7%. Collection efficiency must be measured as described in ASTM D2986 (incorporated by reference, see § 1065.1010), though you may rely on the sample-media manufacturer's measurements reflected in their product ratings to show that you meet the requirement in this paragraph (c)(1)(i). (ii) The filter must be circular, with an overall diameter of (46.50 ±0.60) mm and an exposed diameter of at least 38 mm. See the cassette specifications in paragraph (c)(1)(vii) of this section. (iii) We highly recommend that you use a pure PTFE filter material that does not have any flow-through support bonded to the back and has an overall thickness of (40 ±20) µm. An inert polymer ring may be bonded to the periphery of the filter material for support and for sealing between the filter cassette parts. We consider Polymethylpentene (PMP) and PTFE inert materials for a support ring, but other inert materials may be used. See the cassette specifications in paragraph (c)(1)(vii) of this section. We allow the use of PTFE-coated glass fiber filter material, as long as this filter media selection does not affect your ability to demonstrate compliance with the applicable standards in this chapter, which we base on a pure PTFE filter material. Note that we will use pure PTFE filter material for compliance testing, and we may require you to use pure PTFE filter material for any compliance testing we require, such as for selective enforcement audits. (iv) You may request to use other filter materials or sizes under the provisions of § 1065.10. (v) To minimize turbulent deposition and to deposit PM evenly on a filter, use a filter holder with a 12.5° (from center) divergent cone angle to transition from the transfer-line inside diameter to the exposed diameter of the filter face. Use 300 series stainless steel for this transition. (vi) Maintain a filter face velocity near 100 cm/s with less than 5% of the recorded flow values exceeding 100 cm/s, unless you expect the net PM mass on the filter to exceed 400 µg, assuming a 38 mm diameter filter stain area. Measure face velocity as the volumetric flow rate of the sample at the pressure upstream of the filter and temperature of the filter face as measured in § 1065.140(e), divided by the filter's exposed area. You may use the exhaust stack or CVS tunnel pressure for the upstream pressure if the pressure drop through the PM sampler up to the filter is less than 2 kPa. (vii) Use a clean cassette designed to the specifications of Figure 1 of § 1065.170. In auto changer configurations, you may use cassettes of similar design. Cassettes must be made of one of the following materials: Delrin TM 2 5 (viii) If you keep the cassette in the filter holder after sampling, prevent flow through the filter until either the holder or cassette is removed from the PM sampler. If you remove the cassettes from filter holders after sampling, transfer the cassette to an individual container that is covered or sealed to prevent communication of semi-volatile matter from one filter to another. If you remove the filter holder, cap the inlet and outlet. Keep them covered or sealed until they return to the stabilization or weighing environments. (ix) The filters should not be handled outside of the PM stabilization and weighing environments and should be loaded into cassettes, filter holders, or auto changer apparatus before removal from these environments. (2) You may use other PM sample media that we approve under § 1065.10, including non-filtering techniques. For example, you might deposit PM on an inert substrate that collects PM using electrostatic, thermophoresis, inertia, diffusion, or some other deposition mechanism, as approved. [70 FR 40516, July 13, 2005, as amended at 73 FR 37298, June 30, 2008; 73 FR 59321, Oct. 8, 2008; 76 FR 57440, Sept. 15, 2011;79 FR 23757, Apr. 28, 2014; 81 FR 74162, Oct. 25, 2016; 86 FR 34534, June 29, 2021; 88 FR 4671, Jan. 24, 2023; 89 FR 29794, Apr. 22, 2024] § 1065.190 PM-stabilization and weighing environments for gravimetric analysis. (a) This section describes the two environments required to stabilize and weigh PM for gravimetric analysis: the PM stabilization environment, where filters are stored before weighing; and the weighing environment, where the balance is located. The two environments may share a common space. These volumes may be one or more rooms, or they may be much smaller, such as a glove box or an automated weighing system consisting of one or more countertop-sized environments. (b) We recommend that you keep both the stabilization and the weighing environments free of ambient contaminants, such as dust, aerosols, or semi-volatile material that could contaminate PM samples. We recommend that these environments conform with an “as-built” Class Six clean room specification according to ISO 14644-1 (incorporated by reference, see § 1065.1010); however, we also recommend that you deviate from ISO 14644-1 as necessary to minimize air motion that might affect weighing. We recommend maximum air-supply and air-return velocities of 0.05 m/s in the weighing environment. (c) Verify the cleanliness of the PM-stabilization environment using reference filters, as described in § 1065.390(d). (d) Maintain the following ambient conditions within the two environments during all stabilization and weighing: (1) Ambient temperature and tolerances. (2) Dewpoint. 2 4 2 4 (3) Dewpoint tolerances. Table 1 of § 1065.190—Dewpoint Tolerance as a Function of % PM Change and % Sulfuric Acid PM Expected sulfuric acid fraction of PM ±0.5% PM mass change ±1% PM mass change ±2% PM mass change 5% ±3 °C ±6 °C ±12 °C 50% ±0.3 °C ±0.6 °C ±1.2 °C 100% ±0.15 °C ±0.3 °C ±0.6 °C (e) Verify the following ambient conditions using measurement instruments that meet the specifications in subpart C of this part: (1) Continuously measure dewpoint and ambient temperature. Use these values to determine if the stabilization and weighing environments have remained within the tolerances specified in paragraph (d) of this section for at least 60 min. before weighing sample media (e.g., filters). We recommend that you use an interlock that automatically prevents the balance from reporting values if either of the environments have not been within the applicable tolerances for the past 60 min. (2) Continuously measure atmospheric pressure within the weighing environment. An acceptable alternative is to use a barometer that measures atmospheric pressure outside the weighing environment, as long as you can ensure that atmospheric pressure at the balance is always within ±100 Pa of that outside environment during weighing operations. Record atmospheric pressure as you weigh filters, and use these pressure values to perform the buoyancy correction in § 1065.690. (f) We recommend that you install a balance as follows: (1) Install the balance on a vibration-isolation platform to isolate it from external noise and vibration. (2) Shield the balance from convective airflow with a static-dissipating draft shield that is electrically grounded. (3) Follow the balance manufacturer's specifications for all preventive maintenance. (4) Operate the balance manually or as part of an automated weighing system. (g) Minimize static electric charge in the balance environment, as follows: (1) Electrically ground the balance. (2) Use 300 series stainless steel tweezers if PM sample media (e.g., filters) must be handled manually. (3) Ground tweezers with a grounding strap, or provide a grounding strap for the operator such that the grounding strap shares a common ground with the balance. Make sure grounding straps have an appropriate resistor to protect operators from accidental shock. (4) Provide a static-electricity neutralizer that is electrically grounded in common with the balance to remove static charge from PM sample media (e.g., filters), as follows: (i) You may use radioactive neutralizers such as a Polonium ( 210 (ii) You may use other neutralizers, such as corona-discharge ionizers. If you use a corona-discharge ionizer, we recommend that you monitor it for neutral net charge according to the ionizer manufacturer's recommendations. [70 FR 40516, July 13, 2005, as amended at 73 FR 37299, June 30, 2008; 73 FR 59323, Oct. 8, 2008; 76 FR 57440, Sept. 15, 2011; 88 FR 4671, Jan. 24, 2023; 89 FR 19794, Apr. 22, 2024] § 1065.195 PM-stabilization environment for in-situ analyzers. (a) This section describes the environment required to determine PM in-situ. For in-situ analyzers, such as an inertial balance, this is the environment within a PM sampling system that surrounds the PM sample media (e.g., filters). This is typically a very small volume. (b) Maintain the environment free of ambient contaminants, such as dust, aerosols, or semi-volatile material that could contaminate PM samples. Filter all air used for stabilization with HEPA filters. Ensure that HEPA filters are installed properly so that background PM does not leak past the HEPA filters. (c) Maintain the following thermodynamic conditions within the environment before measuring PM: (1) Ambient temperature. T amb (2) Dewpoint. T dew T amb T dew T amb 2 4 2 4 (3) Dewpoint tolerance. (4) Absolute pressure. (d) Continuously measure dewpoint, temperature, and pressure using measurement instruments that meet the PM-stabilization environment specifications in subpart C of this part. Use these values to determine if the in-situ stabilization environment is within the tolerances specified in paragraph (c) of this section. Do not use any PM quantities that are recorded when any of these parameters exceed the applicable tolerances. (e) If you use an inertial PM balance, we recommend that you install it as follows: (1) Isolate the balance from any external noise and vibration that is within a frequency range that could affect the balance. (2) Follow the balance manufacturer's specifications. (f) If static electricity affects an inertial balance, you may use a static neutralizer, as follows: (1) You may use a radioactive neutralizer such as a Polonium ( 210 85 (2) You may use other neutralizers, such as a corona-discharge ionizer. If you use a corona-discharge ionizer, we recommend that you monitor it for neutral net charge according to the ionizer manufacturer's recommendations. [70 FR 40516, July 13, 2005, as amended at 73 FR 32799, June 30, 2008] Subpart C—Measurement Instruments § 1065.201 Overview and general provisions. (a) Scope. (b) Instrument types. (c) Measurement systems. (d) Redundant systems. (e) Range. (f) Related subparts for laboratory testing. (g) Field testing and testing with PEMS. (h) Recommended practices. [70 FR 40516, July 13, 2005, as amended at 73 FR 37299, June 30, 2008; 75 FR 23033, Apr. 30, 2010; 79 FR 23758, Apr. 29, 2014] § 1065.202 Data updating, recording, and control. Your test system must be able to update data, record data and control systems related to operator demand, the dynamometer, sampling equipment, and measurement instruments. Set up the measurement and recording equipment to avoid aliasing by ensuring that the sampling frequency is at least double that of the signal you are measuring, consistent with good engineering judgment; this may require increasing the sampling rate or filtering the signal. Use data acquisition and control systems that can record at the specified minimum frequencies, as follows: Table 1 of § 1065.202—Data Recording and Control Minimum Frequencies Applicable test protocol section Measured values Minimum a Minimum b c § 1065.510 Speed and torque during an engine step-map 1 Hz 1 mean value per step. § 1065.510 Speed and torque during an engine sweep-map 5 Hz 1 Hz means. § 1065.514; § 1065.530 Transient duty cycle reference and feedback speeds and torques 5 Hz 1 Hz means. § 1065.514; § 1065.530 Steady-state and ramped-modal duty cycle reference and feedback speeds and torques 1 Hz 1 Hz. § 1065.520; § 1065.530; § 1065.550 Continuous concentrations of raw or dilute analyzers 1 Hz. § 1065.520; § 1065.530 § 1065.550 Batch concentrations of raw or dilute analyzers 1 mean value per test interval. § 1065.530; § 1065.545 Diluted exhaust flow rate from a CVS with a heat exchanger upstream of the flow measurement 1 Hz. § 1065.530; § 1065.545 Diluted exhaust flow rate from a CVS without a heat exchanger upstream of the flow measurement 5 Hz 1 Hz means. § 1065.530; § 1065.545 Intake-air or raw-exhaust flow rate 1 Hz means. § 1065.530; § 1065.545 Dilution air flow if actively controlled (for example, a partial-flow PM sampling system) d 5 Hz 1 Hz means. § 1065.530; § 1065.545 Sample flow from a CVS that has a heat exchanger 1 Hz 1 Hz. § 1065.530; § 1065.545 Sample flow from a CVS that does not have a heat exchanger 5 Hz 1 Hz means. a b c d [79 FR 23759, Apr. 28, 2014, as amended at 81 FR 74162, Oct. 25, 2016] § 1065.205 Performance specifications for measurement instruments. Your test system as a whole must meet all the calibrations, verifications, and test-validation criteria specified elsewhere in this part for laboratory testing or field testing, as applicable. We recommend that your instruments meet the specifications in this section for all ranges you use for testing. We also recommend that you keep any documentation you receive from instrument manufacturers showing that your instruments meet the specifications in the following table: [86 FR 34534, June 29, 2021] Measurement of Engine Parameters and Ambient Conditions § 1065.210 Work input and output sensors. (a) Application. (1) We recommend that you measure work inputs and outputs where they cross the system boundary as shown in figure 1 to paragraph (a)(5) of this section. The system boundary is different for air-cooled engines than for liquid-cooled engines. (2) For measurements involving work conversion relative to a system boundary use good engineering judgment to estimate any work-conversion losses in a way that avoids overestimation of total work. For example, if it is impractical to instrument the shaft of an exhaust turbine generating electrical work, you may decide to measure its converted electrical work. As another example, you may decide to measure the tractive ( i.e., η η η (3) If your engine includes an externally powered electrical heater to heat engine exhaust, assume an electrical generator efficiency of 0.67 ( η (4) Do not underestimate any work conversion efficiencies for any components outside the system boundary that do not return work into the system boundary. And do not overestimate any work conversion efficiencies for components outside the system boundary that return work into the system boundary. (5) Figure 1 to this paragraph (a)(5) follows: Figure 1 to paragraph ( a (b) Shaft work. (1) Speed. (2) Torque. (i) Measure torque by mounting a strain gage or similar instrument in-line between the engine and dynamometer. (ii) Measure torque by mounting a strain gage or similar instrument on a lever arm connected to the dynamometer housing. (iii) Calculate torque from internal dynamometer signals, such as armature current, as long as you calibrate this measurement as described in § 1065.310. (c) Electrical work. (d) Pump, compressor or turbine work. [70 FR 40516, July 13, 2005, as amended at 73 FR 37300, June 30, 2008; 79 FR 23760, Apr. 28, 2014; 88 FR 4671, Jan. 24, 2023; 89 FR 29794, Apr. 22, 2024] § 1065.215 Pressure transducers, temperature sensors, and dewpoint sensors. (a) Application. (b) Component requirements. (c) Temperature. (d) Pressure. (e) Dewpoint. [70 FR 40516, July 13, 2005, as amended at 73 FR 37300, June 30, 2008] Flow-Related Measurements § 1065.220 Fuel flow meter. (a) Application. (1) Use the actual value of calculated raw exhaust flow rate in the following cases: (i) For multiplying raw exhaust flow rate with continuously sampled concentrations. (ii) For multiplying total raw exhaust flow with batch-sampled concentrations. (iii) For calculating the dilution air flow for background correction as described in § 1065.667. (2) In the following cases, you may use a fuel flow meter signal that does not give the actual value of raw exhaust, as long as it is linearly proportional to the exhaust molar flow rate's actual calculated value: (i) For feedback control of a proportional sampling system, such as a partial-flow dilution system. (ii) For multiplying with continuously sampled gas concentrations, if the same signal is used in a chemical-balance calculation to determine work from brake-specific fuel consumption and fuel consumed. (b) Component requirements. (c) Recirculating fuel. (d) Flow conditioning. [70 FR 40516, July 13, 2005, as amended at 73 FR 37300, June 30, 2008; 76 FR 57441, Sept. 15, 2011; 81 FR 74162, Oct. 25, 2016; 86 FR 34536, June 29, 2021] § 1065.225 Intake-air flow meter. (a) Application. n int (i) For multiplying raw exhaust flow rate with continuously sampled concentrations. (ii) For multiplying total raw exhaust flow with batch-sampled concentrations. (iii) For verifying minimum dilution ratio for PM batch sampling as described in § 1065.546. (iv) For calculating the dilution air flow for background correction as described in § 1065.667. (2) In the following cases, you may use an intake-air flow meter signal that does not give the actual value of raw exhaust, as long as it is linearly proportional to the exhaust flow rate's actual calculated value: (i) For feedback control of a proportional sampling system, such as a partial-flow dilution system. (ii) For multiplying with continuously sampled gas concentrations, if the same signal is used in a chemical-balance calculation to determine work from brake-specific fuel consumption and fuel consumed. (b) Component requirements. (c) Flow conditioning. [70 FR 40516, July 13, 2005, as amended at 76 FR 57442, Sept. 15, 2011;79 FR 23760, Apr. 28, 2014; 81 FR 74163, Oct. 25, 2016; 86 FR 34536, June 29, 2021] § 1065.230 Raw exhaust flow meter. (a) Application. (1) Use the actual value of calculated raw exhaust in the following cases: (i) Multiply raw exhaust flow rate with continuously sampled concentrations. (ii) Multiply total raw exhaust with batch sampled concentrations. (2) In the following cases, you may use a raw exhaust flow meter signal that does not give the actual value of raw exhaust, as long as it is linearly proportional to the exhaust flow rate's actual calculated value: (i) For feedback control of a proportional sampling system, such as a partial-flow dilution system. (ii) For multiplying with continuously sampled gas concentrations, if the same signal is used in a chemical-balance calculation to determine work from brake-specific fuel consumption and fuel consumed. (b) Component requirements. (c) Flow conditioning. (d) Exhaust cooling. (1) Do not sample PM downstream of the cooling. (2) If cooling causes exhaust temperatures above 202 °C to decrease to below 180 °C, do not sample NMHC downstream of the cooling for compression-ignition engines, two-stroke spark-ignition engines, or four-stroke spark-ignition engines at or below 19 kW. (3) The cooling must not cause aqueous condensation. [70 FR 40516, July 13, 2005, as amended at 79 FR 23761, Apr. 28, 2014] § 1065.240 Dilution air and diluted exhaust flow meters. (a) Application. (b) Component requirements. (1) For constant-volume sampling (CVS) of the total flow of diluted exhaust, you may use a critical-flow venturi (CFV) or multiple critical-flow venturis arranged in parallel, a positive-displacement pump (PDP), a subsonic venturi (SSV), or an ultrasonic flow meter (UFM). Combined with an upstream heat exchanger, either a CFV or a PDP will also function as a passive flow controller in a CVS system. However, you may also combine any flow meter with any active flow control system to maintain proportional sampling of exhaust constituents. You may control the total flow of diluted exhaust, or one or more sample flows, or a combination of these flow controls to maintain proportional sampling. (2) For any other dilution system, you may use a laminar flow element, an ultrasonic flow meter, a subsonic venturi, a critical-flow venturi or multiple critical-flow venturis arranged in parallel, a positive-displacement meter, a thermal-mass meter, an averaging Pitot tube, or a hot-wire anemometer. (c) Flow conditioning. (d) Exhaust cooling. (1) Do not sample PM downstream of the cooling. (2) If cooling causes exhaust temperatures above 202 °C to decrease to below 180 °C, do not sample NMHC downstream of the cooling for compression-ignition engines, two-stroke spark-ignition engines, or four-stroke spark-ignition engines at or below 19 kW. (3) The cooling must not cause aqueous condensation as described in § 1065.140(c)(6). [70 FR 40516, July 13, 2005, as amended at 75 FR 23035, Apr. 30, 2010; 79 FR 23761, Apr. 28, 2014] § 1065.245 Sample flow meter for batch sampling. (a) Application. (b) Component requirements. (c) Flow conditioning. § 1065.247 Diesel exhaust fluid flow rate. (a) Application. (b) ECM. (c) Flow meter. (1) Condition the flow of DEF as needed to prevent wakes, eddies, circulating flows, or flow pulsations from affecting the accuracy or repeatability of the meter. You may accomplish this by using a sufficient length of straight tubing (such as a length equal to at least 10 pipe diameters) or by using specially designed tubing bends, straightening fins, or pneumatic pulsation dampeners to establish a steady and predictable velocity profile upstream of the meter. Condition the flow as needed to prevent any gas bubbles in the fluid from affecting the flow meter. (2) Account for any fluid that bypasses the DEF dosing unit or returns from the dosing unit to the fluid storage tank. (d) Gravimetric scale. [86 FR 34536, June 29, 2021] § 1065.248 Gas divider. (a) Application. (b) Component requirements. CO and C02 Measurements Hydrocarbon, H 2 2 § 1065.250 Nondispersive infrared analyzer. (a) Application. 2 (b) Component requirements. [76 FR 57442, Sept. 15, 2011, as amended at 79 FR 23761, Apr. 28, 2014] § 1065.255 H 2 (a) Component requirements. (b) Instrument types. 2 (1) Magnetic sector mass spectrometer. (2) Raman spectrometer. (c) Interference verification. 2 2 [89 FR 29795, Apr. 22, 2024] § 1065.257 H 2 (a) Component requirements. (b) Measurement principles. (c) Instrument types. 2 (1) Fourier transform infrared (FTIR) analyzer. (2) Laser infrared analyzer. Examples of laser infrared analyzers are pulsed-mode high-resolution narrow band mid-infrared analyzers and modulated continuous wave high-resolution narrow band near or mid-infrared analyzers. (d) Interference verification. (1) Perform CO 2 2 4 7 8 2 2 (2) Perform interference verification for laser infrared analyzers using the procedures of § 1065.375. Use good engineering judgment to determine interference species for laser infrared analyzers. Note that interference species are dependent on the H 2 2 2 [89 FR 29795, Apr. 22, 2024] Hydrocarbon Measurements § 1065.260 Flame-ionization detector. (a) Application. 1 4 (b) Component requirements. 4 (c) Heated FID analyzers. (d) FID fuel and burner air. (e) NMHC and NMOG. 4 (f) NMNEHC. 4 2 6 (g) CH 4 4 4 4 [76 FR 57442, Sept. 15, 2011, as amended at 79 FR 23761, Apr. 28, 2014; 81 FR 74163, Oct. 25, 2016; 86 FR 34536, June 29, 2021; 88 FR 4672, Jan. 24, 2023] § 1065.265 Nonmethane cutter. (a) Application. 4 2 2 (b) System performance. 4 (c) Configuration. (d) Optimization. 4 2 [70 FR 40516, July 13, 2005, as amended at 73 FR 37300, June 30, 2008; 76 FR 57442, Sept. 15, 2011] § 1065.266 Fourier transform infrared analyzer. (a) Application. 4 2 6 (b) Component requirements. (c) Measurement principles. (d) Hydrocarbon species for NMHC and NMNEHC additive determination. (e) NMHC and NMNEHC determination from subtraction of CH 4 and C 2 H 6 from THC. 4 4 2 6 4 2 6 (f) Interference verification. (1) The interference species for CH 4 2 2 2 6 (2) The interference species for C 2 6 2 2 4 (3) The interference species for other measured hydrocarbon species are CO 2 2 4 2 6 [89 FR 29796, Apr. 22, 2024] § 1065.267 Gas chromatograph with a flame ionization detector. (a) Application. 4 2 6 4 (b) Component requirements. [76 FR 57442, Sept. 15, 2011, as amended at 79 FR 23761, Apr. 28, 2014; 81 FR 74163, Oct. 25, 2016; 89 FR 29796, Apr. 22, 2024] § 1065.269 Photoacoustic analyzer for ethanol and methanol. (a) Application. (b) Component requirements. [79 FR 23761, Apr. 28, 2014] NO X 2 3 § 1065.270 Chemiluminescent NO X (a) Application. X X 2 2 X 2 X X (b) Component requirements. (c) NO 2 -to-NO converter. 2 (d) Humidity effects. (1) Connect a CLD downstream of any dryer or chiller that is downstream of an NO 2 (2) Connect a CLD downstream of any dryer or thermal chiller that meets the verification in § 1065.376. (e) Response time. [70 FR 40516, July 13, 2005, as amended at 73 FR 37300, June 30, 2008; 76 FR 57442, Sept. 15, 2011; 79 FR 23761, Apr. 28, 2014] § 1065.272 Nondispersive ultraviolet NO X (a) Application. X X 2 X X (b) Component requirements. (c) NO 2 -to-NO converter. 2 (d) Humidity effects. (1) Connect an NDUV downstream of any dryer or chiller that is downstream of an NO 2 (2) Connect an NDUV downstream of any dryer or thermal chiller that meets the verification in § 1065.376. [70 FR 40516, July 13, 2005, as amended at 73 FR 59323, Oct. 8, 2008; 76 FR 57442, Sept. 15, 2011; 79 FR 23761, Apr. 28, 2014] § 1065.274 Zirconium dioxide (ZrO 2 X (a) Application. 2 X (b) Component requirements. 2 2 (c) Species measured. 2 2 X 2 2 (d) Interference. 3 X [88 FR 4673, Jan. 24, 2023] § 1065.275 N 2 (a) General component requirements. (b) Instrument types. 2 (1) Nondispersive infrared (NDIR) analyzer. (2) Fourier transform infrared (FTIR) analyzer. Use appropriate analytical procedures for interpretation of infrared spectra. For example, EPA Test Method 320 in 40 CFR part 63, appendix A, and ASTM D6348 (incorporated by reference, see § 1065.1010) are considered valid methods for spectral interpretation. (3) Laser infrared analyzer. Examples of laser infrared analyzers are pulsed-mode high-resolution narrow band mid-infrared analyzers, and modulated continuous wave high-resolution narrow band mid-infrared analyzers. (4) Photoacoustic analyzer. Use an optical wheel configuration that gives analytical priority to measurement of the least stable components in the sample. Select a sample integration time of at least 5 seconds. Take into account sample chamber and sample line volumes when determining flush times for your instrument. (5) Gas chromatograph analyzer. You may use a gas chromatograph with an electron-capture detector (GC-ECD) to measure N 2 (i) You may use a packed or porous layer open tubular (PLOT) column phase of suitable polarity and length to achieve adequate resolution of the N 2 2 (ii) Use good engineering judgment to zero your instrument and correct for drift. You do not need to follow the specific procedures in §§ 1065.530 and 1065.550(b) that would otherwise apply. For example, you may perform a span gas measurement before and after sample analysis without zeroing and use the average area counts of the pre-span and post-span measurements to generate a response factor (area counts/span gas concentration), which you then multiply by the area counts from your sample to generate the sample concentration. (c) Interference verification. 2 (1) The interference species for NDIR analyzers are CO, CO 2 2 4 2 2 2 2 2 (2) Use good engineering judgment to determine interference species for FTIR and laser infrared analyzers. Note that interference species, with the exception of H 2 2 2 2 (3) The interference species for photoacoustic analyzers are CO, CO 2 2 [74 FR 56512, Oct. 30, 2009, as amended at 76 FR 57443, Sept. 15, 2011; 78 FR 36398, June 17, 2013;79 FR 23761, Apr. 28, 2014; 81 FR 74163, Oct. 25, 2016; 86 FR 34536, June 29, 2021; 89 FR 29796, Apr. 22, 2024] § 1065.277 NH 3 (a) General component requirements. (b) Instrument types. 3 (1) Nondispersive ultraviolet (NDUV) analyzer. (2) Fourier transform infrared (FTIR) analyzer. Use appropriate analytical procedures for interpretation of infrared spectra. For example, EPA Test Method 320 (see § 1065.266(c)) and ASTM D6348 (incorporated by reference, see § 1065.1010) are considered valid methods for spectral interpretation. (3) Laser infrared analyzer. Examples of laser infrared analyzers are pulsed-mode high-resolution narrow-band mid-infrared analyzers, modulated continuous wave high-resolution narrow band near and mid-infrared analyzers, and modulated continuous-wave high-resolution near-infrared analyzers. A quantum cascade laser, for example, can emit coherent light in the mid-infrared region where NH 3 (c) Sampling system. 3 3 3 (d) Interference verification. 3 (1) Perform SO 2 2 X 3 (2) Perform interference verification for FTIR and laser infrared analyzers using the procedures of § 1065.377. Use good engineering judgment to determine interference species. Note that interference species, with the exception of H 2 3 3 [89 FR 29797, Apr. 22, 2024] O 2 § 1065.280 Paramagnetic and magnetopneumatic O 2 (a) Application. 2 2 (b) Component requirements. [73 FR 37300, June 30, 2008, as amended at 76 FR 57443, Sept. 15, 2011;79 FR 23762, Apr. 28, 2014; 86 FR 34536, June 29, 2021; 89 FR 29797, Apr. 22, 2024] § 1065.284 Zirconium dioxide (ZrO 2 2 (a) Application. 2 2 (b) Component requirements. 2 2 [70 FR 40516, July 13, 2005, as amended at 76 FR 57443, Sept. 15, 2011; 79 FR 23762, Apr. 28, 2014; 89 FR 29797, Apr. 22, 2024] PM Measurements § 1065.290 PM gravimetric balance. (a) Application. (b) Component requirements. (c) Pan design. (1) Use a pan that centers the PM sample media (such as a filter) on the weighing pan. For example, use a pan in the shape of a cross that has upswept tips that center the PM sample media on the pan. (2) Use a pan that positions the PM sample as low as possible. (d) Balance configuration. [73 FR 37300, June 30, 2008, as amended at 75 FR 68462, Nov. 8, 2010] § 1065.295 PM inertial balance for field-testing analysis. (a) Application. (b) Component requirements. (c) Loss correction. (d) Deposition. [73 FR 59259, Oct. 8, 2008, as amended at 75 FR 68462, Nov. 8, 2010; 76 FR 57443, Sept. 15, 2011; 79 FR 23762, Apr. 28, 2014] § 1065.298 Correcting real-time PM measurement based on gravimetric PM filter measurement for field-testing analysis. (a) Application. (b) Measurement principles. (c) Component requirements. (2) Check the calibration and linearity of the photoacoustic and electrical aerosol instruments according to the instrument manufacturer's instructions and the following recommendations: (i) For photoacoustic instruments we recommend one of the following: (A) Use a reference elemental carbon-based PM source to calibrate the instrument Verify the photoacoustic instrument by comparing results either to a gravimetric PM measurement collected on the filter or to an elemental carbon analysis of collected PM. (B) Use a light absorber that has a known amount of laser light absorption to periodically verify the instrument's calibration factor. Place the light absorber in the path of the laser beam. This verification checks the integrity of the microphone sensitivity, the power of the laser diode, and the performance of the analog-to-digital converter. (C) Verify that you meet the linearity requirements in Table 1 of § 1065.307 by generating a maximum reference PM mass concentration (verified gravimetrically) and then using partial-flow sampling to dilute to various evenly distributed concentrations. (ii) For electrical aerosol instruments we recommend one of the following: (A) Use reference monodisperse or polydisperse PM-like particles with a mobility diameter or count median diameter greater than 45 nm. Use an electrometer or condensation particle counter that has a d 50 (B) Verify that you meet the linearity requirements in Table 1 of § 1065.307 using a maximum reference particle concentration, a zero-reference concentration, and at least two other evenly distributed points. Use partial-flow dilution to create the additional reference PM concentrations. The difference between measured values from the electrical aerosol and reference instruments at each point must be no greater than 15% of the mean value from the two measurements at that point. (d) Loss correction. (e) Correction. [88 FR 4673, Jan. 24, 2023] Subpart D—Calibrations and Verifications § 1065.301 Overview and general provisions. (a) This subpart describes required and recommended calibrations and verifications of measurement systems. See subpart C of this part for specifications that apply to individual instruments. (b) You must generally use complete measurement systems when performing calibrations or verifications in this subpart. For example, this would generally involve evaluating instruments based on values recorded with the complete system you use for recording test data, including analog-to-digital converters. For some calibrations and verifications, we may specify that you disconnect part of the measurement system to introduce a simulated signal. (c) If we do not specify a calibration or verification for a portion of a measurement system, calibrate that portion of your system and verify its performance at a frequency consistent with any recommendations from the measurement-system manufacturer, consistent with good engineering judgment. (d) Use NIST-traceable standards to the tolerances we specify for calibrations and verifications. Where we specify the need to use NIST-traceable standards, you may alternatively use international standards recognized by the CIPM Mutual Recognition Arrangement that are not NIST-traceable. [70 FR 40516, July 13, 2005, as amended at 88 FR 4673, Jan. 24, 2023] § 1065.303 Summary of required calibration and verifications. The following table summarizes the required and recommended calibrations and verifications described in this subpart and indicates when these have to be performed: Table 1 of § 1065.303—Summary of Required Calibration and Verifications Type of calibration or verification Minimum frequency a § 1065.305: Accuracy, repeatability and noise Accuracy: Noise: § 1065.307: Linearity verification Speed: Torque: Electrical power, current, and voltage: b Fuel mass flow rate: Fuel mass scale: DEF mass flow rate: c DEF mass scale: Intake-air, dilution air, diluted exhaust, and batch sampler flow rates: d Raw exhaust flow rate: d Gas dividers: Gas analyzers (unless otherwise noted): FTIR and photoacoustic analyzers: GC-ECD: PM balance: Pressure, temperature, and dewpoint: § 1065.308: Continuous gas analyzer system response and updating-recording verification—for gas analyzers not continuously compensated for other gas species Upon initial installation or after system modification that would affect response. § 1065.309: Continuous gas analyzer system-response and updating-recording verification—for gas analyzers continuously compensated for other gas species Upon initial installation or after system modification that would affect response. § 1065.310: Torque Upon initial installation and after major maintenance. § 1065.315: Pressure, temperature, dewpoint Upon initial installation and after major maintenance. § 1065.320: Fuel flow Upon initial installation and after major maintenance. § 1065.325: Intake flow Upon initial installation and after major maintenance. § 1065.330: Exhaust flow Upon initial installation and after major maintenance. § 1065.340: Diluted exhaust flow (CVS) Upon initial installation and after major maintenance. § 1065.341: CVS and PFD flow verification (propane check) Upon initial installation, within 35 days before testing, and after major maintenance. e § 1065.342 Sample dryer verification For thermal chillers: Upon installation and after major maintenance. For osmotic membranes; upon installation, within 35 days of testing, and after major maintenance. § 1065.345: Vacuum leak For laboratory testing: Upon initial installation of the sampling system, within 8 hours before the start of the first test interval of each duty-cycle sequence, and after maintenance such as pre-filter changes. For field testing: After each installation of the sampling system on the vehicle, prior to the start of the field test, and after maintenance such as pre-filter changes. § 1065.350: CO 2 2 Upon initial installation and after major maintenance. § 1065.355: CO NDIR CO 2 2 Upon initial installation and after major maintenance. § 1065.360: FID calibration THC FID optimization, and THC FID verification Calibrate all FID analyzers: upon initial installation and after major maintenance. Optimize and determine CH 4 Verify CH 4 Verify C 2 6 § 1065.362: Raw exhaust FID O 2 For all FID analyzers: upon initial installation, and after major maintenance. For THC FID analyzers: upon initial installation, after major maintenance, and after FID optimization according to § 1065.360. § 1065.365: Nonmethane cutter penetration Upon initial installation, within 185 days before testing, and after major maintenance. § 1065.366: Interference verification for FTIR analyzers Upon initial installation and after major maintenance. § 1065.369: H 2 2 Upon initial installation and after major maintenance. § 1065.370: CLD CO 2 2 Upon initial installation and after major maintenance. § 1065.372: NDUV HC and H 2 Upon initial installation and after major maintenance. § 1065.375: N 2 Upon initial installation and after major maintenance. § 1065.376: Chiller NO 2 Upon initial installation and after major maintenance. § 1065.378: NO 2 Upon initial installation, within 35 days before testing, and after major maintenance. § 1065.390: PM balance and weighing Independent verification: Upon initial installation, within 370 days before testing, and after major maintenance. Zero, span, and reference sample verifications: Within 12 hours of weighing, and after major maintenance. § 1065.395: Inertial PM balance and weighing Independent verification: Upon initial installation, within 370 days before testing, and after major maintenance. Other verifications: Upon initial installation and after major maintenance. a b c d e [86 FR 34536, June 29, 2021] § 1065.305 Verifications for accuracy, repeatability, and noise. (a) This section describes how to determine the accuracy, repeatability, and noise of an instrument. Table 1 of § 1065.205 specifies recommended values for individual instruments. (b) We do not require you to verify instrument accuracy, repeatability, or noise. However, it may be useful to consider these verifications to define a specification for a new instrument, to verify the performance of a new instrument upon delivery, or to troubleshoot an existing instrument. (c) In this section we use the letter “ y y ref (d) Conduct these verifications as follows: (1) Prepare an instrument so it operates at its specified temperatures, pressures, and flows. Perform any instrument linearization or calibration procedures prescribed by the instrument manufacturer. (2) Zero the instrument as you would before an emission test by introducing a zero signal. Depending on the instrument, this may be a zero-concentration gas, a reference signal, a set of reference thermodynamic conditions, or some combination of these. For gas analyzers, use a zero gas that meets the specifications of § 1065.750. (3) Span the instrument as you would before an emission test by introducing a span signal. Depending on the instrument, this may be a span-concentration gas, a reference signal, a set of reference thermodynamic conditions, or some combination of these. For gas analyzers, use a span gas that meets the specifications of § 1065.750. (4) Use the instrument to quantify a NIST-traceable reference quantity, y ref (5) Sample and record values for 30 seconds (you may select a longer sampling period if the recording update frequency is less than 0.5 Hz), record the arithmetic mean, y i i (6) Also, if the reference quantity is not absolutely constant, which might be the case with a reference flow, sample and record values of y refi y ref (7) Subtract the reference value, y ref y refi y i i (8) Repeat the steps specified in paragraphs (d)(2) through (7) of this section until you have ten arithmetic means (y 1 2 i 10 1 2 i 10 1 2 i 10 (9) Use the following values to quantify your measurements: (i) Accuracy. y ref y ref y i y (ii) Repeatability. s ε (iii) Noise. rms σ (10) You may use a measurement instrument that does not meet the accuracy, repeatability, or noise specifications in Table 1 of § 1065.205, as long as you meet the following criteria: (i) Your measurement systems meet all the other required calibration, verification, and validation specifications that apply as specified in the regulations. (ii) The measurement deficiency does not adversely affect your ability to demonstrate compliance with the applicable standards in this chapter. [70 FR 40516, July 13, 2005, as amended at 73 FR 37301, June 30, 2008; 75 FR 23037, Apr. 30, 2010; 79 FR 23763, Apr. 28, 2014; 88 FR 4673, Jan. 24, 2023] § 1065.307 Linearity verification. (a) Scope and frequency. (b) Performance requirements. (c) Procedure. (1) In this paragraph (c), the letter “y” denotes a generic measured quantity, the superscript over-bar denotes an arithmetic mean (such as y ref (2) Use good engineering judgment to operate a measurement system at normal operating conditions. This may include any specified adjustment or periodic calibration of the measurement system. (3) If applicable, zero the instrument as you would before an emission test by introducing a zero signal. Depending on the instrument, this may be a zero-concentration gas, a reference signal, a set of reference thermodynamic conditions, or some combination of these. For gas analyzers, use a zero gas that meets the specifications of § 1065.750 and introduce it directly at the analyzer port. (4) If applicable, span the instrument as you would before an emission test by introducing a span signal. Depending on the instrument, this may be a span-concentration gas, a reference signal, a set of reference thermodynamic conditions, or some combination of these. For gas analyzers, use a span gas that meets the specifications of § 1065.750 and introduce it directly at the analyzer port. (5) If applicable, after spanning the instrument, check zero with the same signal you used in paragraph (c)(3) of this section. Based on the zero reading, use good engineering judgment to determine whether or not to rezero and or re-span the instrument before continuing. (6) For all measured quantities, use the instrument manufacturer's recommendations and good engineering judgment to select reference values, y refi (7) Use the instrument manufacturer's recommendations and good engineering judgment to select the order in which you will introduce the series of reference values. For example, you may select the reference values randomly to avoid correlation with previous measurements and to avoid hysteresis; you may select reference values in ascending or descending order to avoid long settling times of reference signals; or you may select values to ascend and then descend to incorporate the effects of any instrument hysteresis into the linearity verification. (8) Generate reference quantities as described in paragraph (d) of this section. For gas analyzers, use gas concentrations known to be within the specifications of § 1065.750 and introduce them directly at the analyzer port. (9) Introduce a reference signal to the measurement instrument. (10) Allow time for the instrument to stabilize while it measures the value at the reference condition. Stabilization time may include time to purge an instrument and time to account for its response. (11) At a recording frequency of at least f y i (12) Repeat the steps in paragraphs (c)(9) though (11) of this section until measurements are complete at each of the reference conditions. (13) Use the arithmetic means, y i y refi i.e., y refi y i (d) Reference signals. (1) Speed. (2) Torque. (3) Electrical power, current, and voltage. (4) Fuel and DEF mass flow rate (5) Flow rates—inlet air, dilution air, diluted exhaust, raw exhaust, or sample flow. (i) Reference flow meters. (ii) Reference flow values. n refi n ref (6) Gas division. (i) At the outlet of the gas-division system, connect a gas analyzer that meets the linearity verification described in this section and has not been linearized with the gas divider being verified. For example, verify the linearity of an analyzer using a series of reference analytical gases directly from compressed gas cylinders that meet the specifications of § 1065.750. We recommend using a FID analyzer or a PMD or MPD O 2 2 x refi x ref (ii) Using good engineering judgment and the gas divider manufacturer's recommendations, use one or more reference flow meters to measure the flow rates of the gas divider and verify the gas-division value. (7) Continuous constituent concentration. 2 (8) Temperature. T max T max (9) Mass (i) If the container is vented to ambient, fill the container and tubes with fluid above the minimum level used to trigger a fill operation; drain the fluid down to the minimum level; tare the scale; and perform the linearity verification. (ii) If the container is rigid and not vented, drain the fluid down to the minimum level; fill all tubes attached to the container to normal operating pressure; tare the scale; and perform the linearity verification. (e) Measurement systems that require linearity verification. (1) Perform linearity verification more frequently based on the instrument manufacturer's recommendation or good engineering judgment. (2) The expression “ x min a 0 x min x min (3) The expression “max” generally refers to the absolute value of the reference value used during linearity verification that is furthest from zero. This is the value used to scale the first and third tolerances in Table 1 of this section using a 0 SEE p max T max x max x span x max x span (i) For linearity verification of a PM balance, m max (ii) For linearity verification of a torque measurement system used with the engine's primary output shaft, T max (iii) For linearity verification of a fuel mass scale, m max m max m max Where: m max,fuel t min m max,fuel scale (iv) For linearity verification of a DEF mass scale, m max m max m max (v) For linearity verification of a fuel flow rate meter, m max (vi) For linearity verification of a DEF flow rate meter, m max (vii) For linearity verification of an intake-air flow rate meter, n max (viii) For linearity verification of a raw exhaust flow rate meter, n max (ix) For linearity verification of an electrical-power measurement system used to determine the engine's primary output shaft torque, P max (x) For linearity verification of an electrical-current measurement system used to determine the engine's primary output shaft torque, I max (xi) For linearity verification of an electrical-voltage measurement system used to determine the engine's primary output shaft torque, V max (4) The specified ranges are inclusive. For example, a specified range of 0.98-1.02 for a 1 a 1 (5) Table 2 of this section describes optional verification procedures you may perform instead of linearity verification for certain systems. The following provisions apply for the alternative verification procedures: (i) Perform the propane check verification described in § 1065.341 at the frequency specified in Table 1 of § 1065.303. (ii) Perform the carbon balance error verification described in § 1065.543 on all test sequences that use the corresponding system. It must also meet the restrictions listed in Table 2 of this section. You may evaluate the carbon balance error verification multiple ways with different inputs to validate multiple flow-measurement systems. (6) You must meet the a 1 (7) Linearity verification is required for the following temperature measurements: (i) The following temperature measurements always require linearity verification: (A) Air intake. (B) Aftertreatment bed(s), for engines tested with aftertreatment devices subject to cold-start testing. (C) Dilution air for gaseous and PM sampling, including CVS, double-dilution, and partial-flow systems. (D) PM sample. (E) Chiller sample, for gaseous sampling systems that use thermal chillers to dry samples and use chiller temperature to calculate the dewpoint at the outlet of the chiller. For your testing, if you choose to use a high alarm temperature setpoint for the chiller temperature as a constant value in determining the amount of water removed from the emission sample, you may use good engineering judgment to verify the accuracy of the high alarm temperature setpoint instead of linearity verification on the chiller temperature. To verify that the alarm trip point value is no less than 2.0 °C below the reference value at the trip point, we recommend that you input a reference simulated temperature signal below the alarm trip point and increase this signal until the high alarm trips. (F) Transmission oil. (G) Axle gear oil. (ii) Linearity verification is required for the following temperature measurements if these temperature measurements are specified by the engine manufacturer: (A) Fuel inlet. (B) Air outlet to the test cell's charge air cooler air outlet, for engines tested with a laboratory heat exchanger that simulates an installed charge air cooler. (C) Coolant inlet to the test cell's charge air cooler, for engines tested with a laboratory heat exchanger that simulates an installed charge air cooler. (D) Oil in the sump/pan. (E) Coolant before the thermostat, for liquid-cooled engines. (8) Linearity verification is required for the following pressure measurements: (i) The following pressure measurements always require linearity verification: (A) Air intake restriction. (B) Exhaust back pressure as required in § 1065.130(h). (C) Barometer. (D) CVS inlet gage pressure where the raw exhaust enters the tunnel. (E) Sample dryer, for gaseous sampling systems that use either osmotic-membrane or thermal chillers to dry samples. For your testing, if you choose to use a low alarm pressure setpoint for the sample dryer pressure as a constant value in determining the amount of water removed from the emission sample, you may use good engineering judgment to verify the accuracy of the low alarm pressure setpoint instead of linearity verification on the sample dryer pressure. To verify that the trip point value is no more than 4.0 kPa above the reference value at the trip point, we recommend that you input a reference pressure signal above the alarm trip point and decrease this signal until the low alarm trips. (ii) Linearity verification is required for the following pressure measurements if these pressure measurements are specified by the engine manufacturer: (A) The test cell's charge air cooler and interconnecting pipe pressure drop, for turbo-charged engines tested with a laboratory heat exchanger that simulates an installed charge air cooler. (B) Fuel outlet. (f) Performance criteria for measurement systems. Table 1 of § 1065.307—Measurement Systems That Require Linearity Verification Measurement system Quantity Linearity criteria | x min a 1 a 0 a 1 SEE r 2 Speed f n ≤0.05% · f nmax 0.98-1.02 ≤2% · f nmax ≥0.990 Torque T ≤1% · T max 0.98-1.02 ≤2% · T max ≥0.990 Electrical power P ≤1% · P max 0.98-1.02 ≤2% · P max ≥0.990 Current I ≤1% · I max 0.98-1.02 ≤2% · I max ≥0.990 Voltage U ≤1% · U max 0.98-1.02 ≤2% · U max ≥0.990 Fuel flow rate m ≤1% · m max 0.98-1.02 ≤2% · m max ≥0.990 Fuel mass scale m ≤0.3% · m max 0.996-1.004 ≤0.4% · m max ≥0.999 DEF flow rate m ≤1% · m max 0.98-1.02 ≤2% · m max ≥0.990 DEF mass scale m ≤0.3% · m max 0.996-1.004 ≤0.4% · m max ≥0.999 Intake-air flow rate a n ≤1% · n max 0.98-1.02 ≤2% · n max ≥0.990 Dilution air flow rate a n ≤1% · n max 0.98-1.02 ≤2% · n max ≥0.990 Diluted exhaust flow rate a n ≤1% · n max 0.98-1.02 ≤2% · n max ≥0.990 Raw exhaust flow rate a n ≤1% · n max 0.98-1.02 ≤2% · n max ≥0.990 Batch sampler flow rates a n ≤1% · n max 0.98-1.02 ≤2% · n max ≥0.990 Gas dividers x/x span ≤0.5% · x max/x span 0.98-1.02 ≤2% · x max/x span ≥0.990 Gas analyzers for laboratory testing x ≤0.5% · x max 0.99-1.01 ≤1% · x max ≥0.998 Gas analyzers for field testing x ≤1% · x max 0.99-1.01 ≤1% · x max ≥0.998 Electrical aerosol analyzer for field testing x ≤5% · x max 0.85-1.15 ≤10% · x max ≥0.950 Photoacoustic analyzer for field testing x ≤5% · x max 0.90-1.10 ≤10% · x max ≥0.980 PM balance m ≤1% · m max 0.99-1.01 ≤1% · m max ≥0.998 Pressures p ≤1% · p max 0.99-1.01 ≤1% · p max ≥0.998 Dewpoint for intake air, PM-stabilization and balance environments T dew ≤0.5% · T dewmax 0.99-1.01 ≤0.5% · T dewmax ≥0.998 Other dewpoint measurements T dew ≤1% · T dewmax 0.99-1.01 ≤1% · T dewmax ≥0.998 Analog-to-digital conversion of temperature signals T ≤1% · T max 0.99-1.01 ≤1% · T max ≥0.998 a V std V std n V stdmax n max (g) Alternative verification procedures. Table 2 of § 1065.307—Optional Verification to Linearity Verification Measurement system § 1065.341 § 1065.543 Restrictions for § 1065.543 Intake-air flow rate Yes Yes Determine raw exhaust flow rate using the intake-air flow rate signal as an input into Eq. 1065.655-24 and determine mass of CO 2 Dilution air flow rate for CVS Yes No Not allowed. Diluted exhaust flow rate for CVS Yes Yes Determine mass of CO 2 Raw exhaust flow rate for exhaust stack Yes Yes Determine mass of CO 2 Flow measurements in a PFD (usually dilution air and diluted exhaust streams) used to determine the dilution ratio in the PFD Yes Yes Determine mass of CO 2 Batch sampler flow rates Yes No Not allowed. Fuel mass flow rate No Yes Determine mass of a carbon-carrying fluid stream used as an input into Eq. 1065.643-1 using the fuel mass flow rate meter. Fuel mass scale No Yes Determine mass of a carbon-carrying fluid stream used as an input into Eq. 1065.643-1 using the fuel mass scale. [79 FR 23763, Apr. 28, 2014, as amended at 86 FR 34538, June 29, 2021; 87 FR 64865, Oct. 26, 2022; 88 FR 4673, Jan. 24, 2023] § 1065.308 Continuous gas analyzer system-response and updating-recording verification—for gas analyzers not continuously compensated for other gas species. (a) Scope and frequency. (b) Measurement principles. t 50 t 50 t 50 (c) System requirements. (1) The product of the mean rise time, t 10-90 t 90-10 (2) The frequency at which the system records an updated concentration must be at least 5 Hz. This criterion assumes that the frequency content of significant changes in emission concentrations during emission testing do not exceed 1 Hz. Also, the mean rise time must be at or below 10 seconds and the mean fall time must be at or below 10 seconds. (3) You may use other criteria if we approve the criteria in advance. (4) You may meet the overall PEMS verification in § 1065.920 instead of the verification in this section for field testing with PEMS. (d) Procedure. (1) Instrument setup. (2) Equipment setup. t 50 2 2 3 8 4 (3) Data collection. (ii) Allow for stabilization, accounting for transport delays and the slowest analyzer's full response. (iii) Start recording data. For this verification you must record data at a frequency greater than or equal to that of the updating-recording frequency used during emission testing. You may not use interpolation or filtering to alter the recorded values. (iv) Switch the flow to allow the blended span gases to flow to the analyzer. If you intend to use the data from this test to determine t 50 t 0 (v) Allow for transport delays and the slowest analyzer's full response. (vi) Switch the flow to allow zero gas to flow to the analyzer. If you intend to use the data from this test to determine t 50 t 100 (vii) Allow for transport delays and the slowest analyzer's full response. (viii) Repeat the steps in paragraphs (d)(3)(iv) through (vii) of this section to record seven full cycles, ending with zero gas flowing to the analyzers. (ix) Stop recording. (e) Performance evaluation. t 10-90 t 90-10 (2) If a measurement system fails the criterion in paragraph (e)(1) of this section, ensure that signals from the system are updated and recorded at a frequency of at least 5 Hz. In no case may the mean rise time or mean fall time be greater than 10 seconds. (3) If a measurement system fails the criteria in paragraphs (e)(1) and (2) of this section, you may use the measurement system only if the deficiency does not adversely affect your ability to show compliance with the applicable standards in this chapter. (f) Transformation time, t 50 t 50 t 0-50 t 100-50 t 50 (g) Optional procedure. (1) If your probe is sampling from a continuously flowing gas stream (e.g., a CVS tunnel), you may adjust the span gas flow rate to be different than the sample flow rate. (2) If your probe is sampling from a gas stream that is not continuously flowing (e.g., a raw exhaust stack), you must adjust the span gas flow rate to be less than the sample flow rate so ambient air is always being drawn into the probe inlet. This avoids errors associated with overflowing span gas out of the probe inlet and drawing it back in when sampling ambient air. (3) When sampling ambient air or ambient air mixed with span gas, all the analyzer readings must be stable within ±0.5% of the target gas concentration step size. If any analyzer reading is outside the specified range, you must resolve the problem and verify that all the analyzer readings meet this specification. (4) For oxygen analyzers, you may use purified N 2 2 2 2 [73 FR 59325, Oct. 8, 2008, as amended at 79 FR 23766, Apr. 28, 2014; 88 FR 4674, Jan. 24, 2023] § 1065.309 Continuous gas analyzer system-response and updating-recording verification—for gas analyzers continuously compensated for other gas species. (a) Scope and frequency. 50 4 (b) Measurement principles. t 50 t 50 t 50 (c) System requirements. 2 2 (1) The product of the mean rise time, t 10-90 t 90-10 (2) The frequency at which the system records an updated concentration must be at least 5 Hz. This criterion assumes that the frequency content of significant changes in emission concentrations during emission testing do not exceed 1 Hz. Also, the mean rise time must be at or below 10 seconds and the mean fall time must be at or below 10 seconds. (3) You may use other criteria if we approve them in advance. (4) You may meet the overall PEMS verification in § 1065.920 instead of the verification in this section for field testing with PEMS. (d) Procedure. (1) Instrument setup. (2) Equipment setup. We recommend using minimal lengths of gas transfer lines between all connections and fast-acting three-way valves (2 inlets, 1 outlet) to control the flow of zero and blended span gases to the sample system's probe inlet or a tee near the outlet of the probe. If you inject the gas at a tee near the outlet of the probe, you may correct the transformation time, t 50 2 2 2 3 8 4 2 2 2 2 2 3 8 4 2 2 2 2 2 2 2 2 2 2 (3) Data collection. (ii) Allow for stabilization, accounting for transport delays and the slowest analyzer's full response. (iii) Start recording data. For this verification you must record data at a frequency greater than or equal to that of the updating-recording frequency used during emission testing. You may not use interpolation or filtering to alter the recorded values. (iv) Switch the flow to allow the blended span gases to flow to the analyzer. If you intend to use the data from this test to determine t 50 t 0 (v) Allow for transport delays and the slowest analyzer's full response. (vi) Switch the flow to allow zero gas to flow to the analyzer. If you intend to use the data from this test to determine t 50 t 100 (vii) Allow for transport delays and the slowest analyzer's full response. (viii) Repeat the steps in paragraphs (d)(3)(iv) through (vii) of this section to record seven full cycles, ending with zero gas flowing to the analyzers. (ix) Stop recording. (e) Performance evaluations. t 10-90 t 90-10 (2) If a measurement system fails the criterion in paragraph (e)(1) of this section, ensure that signals from the system are updated and recorded at a frequency of at least 5 Hz. In no case may the mean rise time or mean fall time be greater than 10 seconds. (3) If a measurement system fails the criteria in paragraphs (e)(1) and (2) of this section, you may use the measurement system only if the deficiency does not adversely affect your ability to show compliance with the applicable standards in this chapter. (f) Transformation time, t 50 , determination. t 50 t 0-50 t 100-50 t 50 (g) Optional procedure. (h) Analyzers with H 2 O compensation sampling downstream of a sample dryer. 2 (1) The analyzer is located downstream of a sample dryer. (2) The maximum value for H 2 [73 FR 59326, Oct. 8, 2008, as amended at 75 FR 23039, Apr. 30, 2010; 79 FR 23767, Apr. 28, 2014; 86 FR 34541, June 29, 2021; 88 FR 4674, Jan. 24, 2023] Measurement of Engine Parameters and Ambient Conditions § 1065.310 Torque calibration. (a) Scope and frequency. (b) Recommended procedure to quantify lever-arm length. (c) Recommended procedure to quantify reference force. (1) Dead-weight calibration. (2) Strain gage, load transducer, or proving ring calibration. [79 FR 23768, Apr. 28, 2014] § 1065.315 Pressure, temperature, and dewpoint calibration. (a) Calibrate instruments for measuring pressure, temperature, and dewpoint upon initial installation. Follow the instrument manufacturer's instructions and use good engineering judgment to repeat the calibration, as follows: (1) Pressure. (2) Temperature. T max. T max (3) Dewpoint. (b) You may remove system components for off-site calibration. We recommend specifying calibration reference quantities that are NIST-traceable within ±0.5% uncertainty. [70 FR 40516, July 13, 2005, as amended at 73 FR 37305, June 30, 2008; 75 FR 23040, Apr. 30, 2010; 79 FR 23768, Apr. 28, 2014; 88 FR 4674, Jan. 24, 2023; 89 FR 29797, Apr. 22, 2024] Flow-Related Measurements § 1065.320 Fuel-flow calibration. (a) Calibrate fuel-flow meters upon initial installation. Follow the instrument manufacturer's instructions and use good engineering judgment to repeat the calibration. (b) [Reserved] (c) You may remove system components for off-site calibration. When installing a flow meter with an off-site calibration, we recommend that you consider the effects of the tubing configuration upstream and downstream of the flow meter. We recommend specifying calibration reference quantities that are NIST-traceable within ±0.5% uncertainty. [70 FR 40516, July 13, 2005, as amended at 86 FR 34541, June 29, 2021; 88 FR 4674, Jan. 24. 2023] § 1065.325 Intake-flow calibration. (a) Calibrate intake-air flow meters upon initial installation. Follow the instrument manufacturer's instructions and use good engineering judgment to repeat the calibration. We recommend using a calibration subsonic venturi, ultrasonic flow meter or laminar flow element. We recommend using calibration reference quantities that are NIST-traceable within ±0.5% uncertainty. (b) You may remove system components for off-site calibration. When installing a flow meter with an off-site calibration, we recommend that you consider the effects of the tubing configuration upstream and downstream of the flow meter. We recommend specifying calibration reference quantities that are NIST-traceable within ±0.5% uncertainty. (c) If you use a subsonic venturi or ultrasonic flow meter for intake flow measurement, we recommend that you calibrate it as described in § 1065.340. [70 FR 40516, July 13, 2005, as amended at 88 FR 4675, Jan. 24, 2023] § 1065.330 Exhaust-flow calibration. (a) Calibrate exhaust-flow meters upon initial installation. Follow the instrument manufacturer's instructions and use good engineering judgment to repeat the calibration. We recommend that you use a calibration subsonic venturi or ultrasonic flow meter and simulate exhaust temperatures by incorporating a heat exchanger between the calibration meter and the exhaust-flow meter. If you can demonstrate that the flow meter to be calibrated is insensitive to exhaust temperatures, you may use other reference meters such as laminar flow elements, which are not commonly designed to withstand typical raw exhaust temperatures. We recommend using calibration reference quantities that are NIST-traceable within ±0.5% uncertainty. (b) You may remove system components for off-site calibration. When installing a flow meter with an off-site calibration, we recommend that you consider the effects of the tubing configuration upstream and downstream of the flow meter. We recommend specifying calibration reference quantities that are NIST-traceable within ±0.5% uncertainty. (c) If you use a subsonic venturi or ultrasonic flow meter for raw exhaust flow measurement, we recommend that you calibrate it as described in § 1065.340. [70 FR 40516, July 13, 2005, as amended at 88 FR 4675, Jan. 24, 2023] § 1065.340 Diluted exhaust flow (CVS) calibration. (a) Overview. (b) Scope and frequency. i.e. (c) Ex-situ CFV and SSV calibration. (1) Upon installation of the CFV or SSV into the CVS, use good engineering judgment to verify that you have not introduced any leaks between the CVS inlet and the venturi. (2) After ex-situ venturi calibration, you must verify all venturi flow combinations for CFVs or at minimum of 10 flow points for an SSV using the propane check as described in § 1065.341. Your propane check result for each venturi flow point may not exceed the tolerance in § 1065.341(f)(5). (3) To verify your ex-situ calibration for a CVS with more than a single CFV, perform the following check to verify that there are no flow meter entrance effects that can prevent you from passing this verification. (i) Use a constant flow device like a CFO kit to deliver a constant flow of propane to the dilution tunnel. (ii) Measure hydrocarbon concentrations at a minimum of 10 separate flow rates for an SSV flow meter, or at all possible flow combinations for a CFV flow meter, while keeping the flow of propane constant. We recommend selecting CVS flow rates in a random order. (iii) Measure the concentration of hydrocarbon background in the dilution air at the beginning and end of this test. Subtract the average background concentration from each measurement at each flow point before performing the regression analysis in paragraph (c)(3)(iv) of this section. (iv) Perform a power regression using all the paired values of flow rate and corrected concentration to obtain a relationship in the form of y a x b b (d) Reference flow meter. (e) Configuration. (f) PDP calibration. (1) Connect the system as shown in Figure 1 of this section. (2) Leaks between the calibration flow meter and the PDP must be less than 0.3% of the total flow at the lowest calibrated flow point; for example, at the highest restriction and lowest PDP-speed point. (3) While the PDP operates, maintain a constant temperature at the PDP inlet within ±2% of the mean absolute inlet temperature, T in (4) Set the PDP speed to the first speed point at which you intend to calibrate. (5) Set the variable restrictor to its wide-open position. (6) Operate the PDP for at least 3 min to stabilize the system. Continue operating the PDP and record the mean values of at least 30 seconds of sampled data of each of the following quantities: (i) The mean flow rate of the reference flow meter, n ref n ref (ii) The mean temperature at the PDP inlet, T in (iii) The mean static absolute pressure at the PDP inlet, p in (iv) The mean static absolute pressure at the PDP outlet, p out (v) The mean PDP speed, f nPDP (7) Incrementally close the restrictor valve to decrease the absolute pressure at the inlet to the PDP, p in (8) Repeat the steps in paragraphs (e)(6) and (7) of this section to record data at a minimum of six restrictor positions ranging from the wide open restrictor position to the minimum expected pressure at the PDP inlet or the maximum expected differential (outlet minus inlet) pressure across the PDP during testing. (9) Calibrate the PDP by using the collected data and the equations in § 1065.640. (10) Repeat the steps in paragraphs (e)(6) through (9) of this section for each speed at which you operate the PDP. (11) Use the equations in § 1065.642 to determine the PDP flow equation for emission testing. (12) Verify the calibration by performing a CVS verification ( i.e. (13) During emission testing ensure that the PDP is not operated either below the lowest inlet pressure point or above the highest differential pressure point in the calibration data. (g) SSV calibration. C d, (1) Connect the system as shown in Figure 1 of this section. (2) Verify that any leaks between the calibration flow meter and the SSV are less than 0.3% of the total flow at the highest restriction. (3) Start the blower downstream of the SSV. (4) While the SSV operates, maintain a constant temperature at the SSV inlet within ±2% of the mean absolute inlet temperature, T in (5) Set the variable restrictor or variable-speed blower to a flow rate greater than the greatest flow rate expected during testing. You may not extrapolate flow rates beyond calibrated values, so we recommend that you make sure the Reynolds number, Re # Re # (6) Operate the SSV for at least 3 min to stabilize the system. Continue operating the SSV and record the mean of at least 30 seconds of sampled data of each of the following quantities: (i) The mean flow rate of the reference flow meter n ref n ref (ii) Optionally, the mean dewpoint of the calibration air, T dew (iii) The mean temperature at the venturi inlet, T in (iv) The mean static absolute pressure at the venturi inlet, P in (v) The mean static differential pressure between the static pressure at the venturi inlet and the static pressure at the venturi throat, Δ P SSV (7) Incrementally close the restrictor valve or decrease the blower speed to decrease the flow rate. (8) Repeat the steps in paragraphs (g)(6) and (7) of this section to record data at a minimum of ten flow rates. (9) Determine an equation to quantify C d Re # C d Re # (10) Verify the calibration by performing a CVS verification ( i.e., C d Re # (11) Use the SSV only between the minimum and maximum calibrated Re # Re # (12) Use the equations in § 1065.642 to determine SSV flow during a test. (h) CFV calibration. C d, r, (1) Connect the system as shown in Figure 1 of this section. (2) Verify that any leaks between the calibration flow meter and the CFV are less than 0.3% of the total flow at the highest restriction. (3) Start the blower downstream of the CFV. (4) While the CFV operates, maintain a constant temperature at the CFV inlet within ±2% of the mean absolute inlet temperature, T in (5) Set the variable restrictor to its wide-open position. Instead of a variable restrictor, you may alternately vary the pressure downstream of the CFV by varying blower speed or by introducing a controlled leak. Note that some blowers have limitations on nonloaded conditions. (6) Operate the CFV for at least 3 min to stabilize the system. Continue operating the CFV and record the mean values of at least 30 seconds of sampled data of each of the following quantities: (i) The mean flow rate of the reference flow meter, n ref n ref (ii) The mean dewpoint of the calibration air, T dew (iii) The mean temperature at the venturi inlet, T in (iv) The mean static absolute pressure at the venturi inlet, P in (v) The mean static differential pressure between the CFV inlet and the CFV outlet, Δ P CFV (7) Incrementally close the restrictor valve or decrease the downstream pressure to decrease the differential pressure across the CFV, Δp CFV (8) Repeat the steps in paragraphs (f)(6) and (7) of this section to record mean data at a minimum of ten restrictor positions, such that you test the fullest practical range of Δ P CFV (9) Determine C d r, (10) Use C d r, (11) Verify the calibration by performing a CVS verification ( i.e., (12) If your CVS is configured to operate more than one CFV at a time in parallel, calibrate your CVS by one of the following: (i) Calibrate every combination of CFVs according to this section and § 1065.640. Refer to § 1065.642 for instructions on calculating flow rates for this option. (ii) Calibrate each CFV according to this section and § 1065.640. Refer to § 1065.642 for instructions on calculating flow rates for this option. (i) Ultrasonic flow meter calibration. [70 FR 40516, July 13, 2005, as amended at 73 FR 37305, June 30, 2008; 75 FR 68463, Nov. 8, 2010; 76 FR 57445, Sept. 15, 2011; 81 FR 74165, Oct. 25, 2016] § 1065.341 CVS and PFD flow verification (propane check). This section describes two optional methods, using propane as a tracer gas, to verify CVS and PFD flow streams. You may use good engineering judgment and safe practices to use other tracer gases, such as CO 2 (a) A propane check uses either a reference mass or a reference flow rate of C 3 8 3 8 3 8 (b) Prepare for the propane check as follows: (1) If you use a reference mass of C 3 8 3 8 3 8 3 8 3 8 3 8 (2) Select appropriate flow rates for the CVS and C 3 8 (3) Select a C 3 8 3 8 (4) Operate and stabilize the CVS. (5) Preheat or pre-cool any heat exchangers in the sampling system. (6) Allow heated and cooled components such as sample lines, filters, chillers, and pumps to stabilize at operating temperature. (7) You may purge the HC sampling system during stabilization. (8) If applicable, perform a vacuum side leak verification of the HC sampling system as described in § 1065.345. (9) You may also conduct any other calibrations or verifications on equipment or analyzers. (c) If you performed the vacuum-side leak verification of the HC sampling system as described in paragraph (b)(8) of this section, you may use the HC contamination procedure in § 1065.520(g) to verify HC contamination. Otherwise, zero, span, and verify contamination of the HC sampling system, as follows: (1) Select the lowest HC analyzer range that can measure the C 3 8 3 8 (2) Zero the HC analyzer using zero air introduced at the analyzer port. (3) Span the HC analyzer using C 3 8 (4) Overflow zero air at the HC probe inlet or into a tee near the outlet of the probe. (5) Measure the stable HC concentration of the HC sampling system as overflow zero air flows. For batch HC measurement, fill the batch container (such as a bag) and measure the HC overflow concentration. (6) If the overflow HC concentration exceeds 2 µmol/mol, do not proceed until contamination is eliminated. Determine the source of the contamination and take corrective action, such as cleaning the system or replacing contaminated portions. (7) When the overflow HC concentration does not exceed 2 µmol/mol, record this value as x THCinit (d) Perform the propane check as follows: (1) For batch HC sampling, connect clean storage media, such as evacuated bags. (2) Operate HC measurement instruments according to the instrument manufacturer's instructions. (3) If you will correct for dilution air background concentrations of HC, measure and record background HC in the dilution air. (4) Zero any integrating devices. (5) Begin sampling, and start any flow integrators. (6) Release the contents of the C 3 8 3 8 (7) Continue to release the cylinder's contents until at least enough C 3 8 3 8 3 8 (8) Shut off the C 3 8 (9) Stop sampling and stop any integrators. (e) Perform post-test procedure as follows: (1) If you used batch sampling, analyze batch samples as soon as practical. (2) After analyzing HC, correct for contamination and background. (3) Calculate total C 3 8 3 8 M C3H8 M HC (4) If you use a reference mass, determine the cylinder's propane mass within ±0.5% and determine the C 3 8 (5) Subtract the reference C 3 8 (f) A failed propane check might indicate one or more problems requiring corrective action, as follows: Table 1 of § 1065.341—Troubleshooting Guide for Propane Checks Problem Recommended corrective action Incorrect analyzer calibration Recalibrate, repair, or replace the FID analyzer. Leaks Inspect CVS tunnel, connections, fasteners, and HC sampling system. Repair or replace components. Poor mixing Perform the verification as described in this section while traversing a sampling probe across the tunnel's diameter, vertically and horizontally. If the analyzer response indicates any deviation exceeding ±2% of the mean measured concentration, consider operating the CVS at a higher flow rate or installing a mixing plate or orifice to improve mixing. Hydrocarbon contamination in the sample system Perform the hydrocarbon-contamination verification as described in § 1065.520. Change in CVS calibration Perform a calibration of the CVS flow meter as described in § 1065.340. Flow meter entrance effects Inspect the CVS tunnel to determine whether the entrance effects from the piping configuration upstream of the flow meter adversely affect the flow measurement. Other problems with the CVS or sampling verification hardware or software Inspect the CVS system and related verification hardware, and software for discrepancies. (g) You may verify flow measurements in a PFD (usually dilution air and diluted exhaust streams) for determining the dilution ratio in the PFD using the following method: (1) Configure the HC sampling system to extract a sample from the PFD's diluted exhaust stream (such as near a PM filter). If the absolute pressure at this location is too low to extract an HC sample, you may sample HC from the PFD's pump exhaust. Use caution when sampling from pump exhaust because an otherwise acceptable pump leak downstream of a PFD diluted exhaust flow meter will cause a false failure of the propane check. (2) Perform the propane check described in paragraphs (b), (c), and (d) of this section, but sample HC from the PFD's diluted exhaust stream. Inject the propane in the same exhaust stream that the PFD is sampling from (either CVS or raw exhaust stack). (3) Calculate C 3 8 (4) Subtract the reference C 3 8 (h) Table 2 of § 1065.307 describes optional verification procedures you may perform instead of linearity verification for certain flow-measurement systems. Performing carbon balance error verification also replaces any required propane checks. [86 FR 34541, June 29, 2021, as amended at 88 FR 4675, Jan. 24, 2023; 89 FR 29797, Apr. 22, 2024] § 1065.342 Sample dryer verification. (a) Scope and frequency. (b) Measurement principles. X (c) System requirements. T dew p total (d) Sample dryer verification procedure. (1) Use PTFE or stainless steel tubing to make necessary connections. (2) Humidify room air, purified N 2 2 2 2 (3) Introduce the humidified gas upstream of the sample dryer. You may disconnect the transfer line from the probe and introduce the humidified gas at the inlet of the transfer line of the sample system used during testing. You may use the sample pumps in the sample system to draw gas through the vessel. (4) Maintain the sample lines, fittings, and valves from the location where the humidified gas water content is measured to the inlet of the sampling system at a temperature at least 5 °C above the local humidified gas dewpoint. For dryers used in NO X (5) Measure the humidified gas dewpoint, T dew p total (6) Measure the humidified gas dewpoint, T dew p total p total (7) The sample dryer meets the verification if the dewpoint at the sample dryer pressure as measured in paragraph (d)(6) of this section is less than the dewpoint corresponding to the sample dryer specifications as determined in § 1065.145(e)(2) plus 2 °C or if the mole fraction of water as measured in (d)(6) is less than the corresponding sample dryer specifications plus 0.002 mol/mol. (e) Alternate sample dryer verification procedure. [73 FR 37307, June 30, 2008, as amended at 73 FR 59328, Oct. 8, 2008; 75 FR 23040, Apr. 30, 2010; 86 FR 34543, June 29, 2021] § 1065.345 Vacuum-side leak verification. (a) Scope and frequency. (b) Measurement principles. (c) Low-flow leak test. (1) Seal the probe end of the system by taking one of the following steps: (i) Cap or plug the end of the sample probe. (ii) Disconnect the transfer line at the probe and cap or plug the transfer line. (iii) Close a leak-tight valve located in the sample transfer line within 92 cm of the probe. (2) Operate all vacuum pumps. After stabilizing, verify that the flow through the vacuum-side of the sampling system is less than 0.5% of the system's normal in-use flow rate. You may estimate typical analyzer and bypass flows as an approximation of the system's normal in-use flow rate. (d) Dilution-of-span-gas leak test. 2 2 (1) Prepare a gas analyzer as you would for emission testing. (2) Supply reference gas to the analyzer span port and record the measured value. (3) Route overflow reference gas to the inlet of the sample probe or at a tee fitting in the transfer line near the exit of the probe. You may use a valve upstream of the overflow fitting to prevent overflow of reference gas out of the inlet of the probe, but you must then provide an overflow vent in the overflow supply line. (4) Verify that the measured overflow reference gas concentration is within ±0.5% of the concentration measured in paragraph (d)(2) of this section. A measured value lower than expected indicates a leak, but a value higher than expected may indicate a problem with the reference gas or the analyzer itself. A measured value higher than expected does not indicate a leak. (e) Vacuum-decay leak test. (1) Seal the probe end of the system as close to the probe opening as possible by taking one of the following steps: (i) Cap or plug the end of the sample probe. (ii) Disconnect the transfer line at the probe and cap or plug the transfer line. (iii) Close a leak-tight valve located in the sample transfer line within 92 cm of the probe. (2) Operate all vacuum pumps. Draw a vacuum that is representative of normal operating conditions. In the case of sample bags, we recommend that you repeat your normal sample bag pump-down procedure twice to minimize any trapped volumes. (3) Turn off the sample pumps and seal the system. Measure and record the absolute pressure of the trapped gas and optionally the system absolute temperature. Wait long enough for any transients to settle and long enough for a leak at 0.5% to have caused a pressure change of at least 10 times the resolution of the pressure transducer, then again record the pressure and optionally temperature. (4) Calculate the leak flow rate based on an assumed value of zero for pumped-down bag volumes and based on known values for the sample system volume, the initial and final pressures, optional temperatures, and elapsed time. Using the calculations specified in § 1065.644, verify that the vacuum-decay leak flow rate is less than 0.5% of the system's normal in-use flow rate. [73 FR 37307, June 30, 2008, as amended at 73 FR 59328, Oct. 8, 2008; 75 FR 23040, Apr. 30, 2010; 81 FR 74167, Oct. 25, 2016; 88 FR 4675, Jan. 24, 2023] CO and CO 2 § 1065.350 H 2 2 (a) Scope and frequency. 2 2 (b) Measurement principles. 2 2 (c) System requirements. 2 2 (d) Procedure. (1) Start, operate, zero, and span the CO 2 (2) Create a humidified test gas by bubbling zero gas that meets the specifications in § 1065.750 through distilled H 2 2 2 2 (3) Introduce the humidified test gas into the sample system. You may introduce it downstream of any sample dryer, if one is used during testing. (4) If the sample is not passed through a dryer during this verification test, measure the H 2 x H2O T dew p total x H2O 2 2 2 2 2 (5) If a sample dryer is not used in this verification test, use good engineering judgment to prevent condensation in the transfer lines, fittings, or valves from the point where x H2O x H2O (6) Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the transfer line and to account for analyzer response. (7) Operate the analyzer to get a reading for CO 2 (8) The analyzer meets the interference verification if the result of paragraph (d)(7) of this section meets the tolerance in paragraph (c) of this section. (e) Exceptions. (1) You may omit this verification if you can show by engineering analysis that for your CO 2 2 2 (2) You may use a CO 2 [70 FR 40516, July 13, 2005, as amended at 73 FR 37308, June 30, 2008; 73 FR 59328, Oct. 8, 2008; 75 FR 23040, Apr. 30, 2010; 76 FR 57447, Sept. 15, 2011; 79 FR 23768, Apr. 28, 2014; 86 FR 34543, June 29, 2021; 88 FR 4675, Jan. 24, 2023; 89 FR 29797, Apr. 22, 2024] § 1065.355 H 2 2 (a) Scope and frequency. 2 2 (b) Measurement principles. 2 2 (c) System requirements. 2 2 (d) Procedure. (1) Start, operate, zero, and span the CO NDIR analyzer as you would before an emission test. If the sample is passed through a dryer during emission testing, you may run this verification test with the dryer if it meets the requirements of § 1065.342. Operate the dryer at the same conditions as you will for an emission test. You may also run this verification test without the sample dryer. (2) Create a humidified CO 2 2 2 2 2 2 2 (3) Introduce the humidified CO 2 (4) If the sample is not passed through a dryer during this verification test, measure the H 2 x H2O 2 T dew p total x H 2 O 2 2 2 2 2 (5) If a sample dryer is not used in this verification test, use good engineering judgment to prevent condensation in the transfer lines, fittings, or valves from the point where x H2O x H2O (6) Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the transfer line and to account for analyzer response. (7) Operate the analyzer to get a reading for CO concentration and record results for 30 seconds. Calculate the arithmetic mean of this data. (8) The analyzer meets the interference verification if the result of paragraph (d)(7) of this section meets the tolerance in paragraph (c) of this section. (9) You may also run interference procedures for CO 2 2 2 2 2 2 2 2 (e) Exceptions. (1) You may omit this verification if you can show by engineering analysis that for your CO sampling system and your emission-calculation procedures, the combined CO 2 2 (2) You may use a CO NDIR analyzer that you determine does not meet this verification, as long as you try to correct the problem and the measurement deficiency does not adversely affect your ability to show that engines comply with all applicable emission standards. [70 FR 40516, July 13, 2005, as amended at 73 FR 37308, June 30, 2008; 73 FR 59328, Oct. 8, 2008; 75 FR 23041, Apr. 30, 2010; 79 FR 23769, Apr. 28, 2014; 86 FR 34543, June 29, 2021; 89 FR 29798, Apr. 22, 2024] H 2 § 1065.357 CO 2 2 (a) Scope and frequency. 2 2 (b) Measurement principles. 2 2 (c) System requirements. 2 2 (d) Procedure. (1) Start, operate, zero, and span the H 2 (2) Use a CO 2 2 (3) Introduce the CO 2 (4) Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the transfer line and to account for analyzer response. (5) Operate the analyzer to get a reading for H 2 (6) The analyzer meets the interference verification if the result of paragraph (d)(5) of this section meets the tolerance in paragraph (c) of this section. (e) Exceptions. (1) You may omit this verification for CO 2 (2) You may omit this verification if you can show by engineering analysis that for your H 2 2 2 (3) You may use an H 2 [89 FR 29798, Apr. 22, 2024] Hydrocarbon Measurements § 1065.360 FID optimization and verification. (a) Scope and frequency. (1) Optimize the response to various hydrocarbons after initial analyzer installation and after major maintenance as described in paragraph (c) of this section. (2) Determine the methane (CH 4 (3) If you determine NMNEHC by subtracting from measured THC, determine the ethane (C 2 6 2 6 (4) You may determine the methane (CH 4 2 6 (b) Calibration. 3 8 4 4 2 4 4 1 3 8 4 (c) THC FID response optimization. (d) THC FID CH 4 response factor determination. 4 3 8 4 RF CH4[THC-FID], RF CH4[THC-FID] 4 RF CH4[THC-FID] RF CH4[THC-FID] 4 (1) Select a C 3 8 3 8 (2) Select a CH 4 4 (3) Start and operate the FID analyzer according to the manufacturer's instructions. (4) Confirm that the FID analyzer has been calibrated using C 3 8 1 3 8 (5) Zero the FID with a zero gas that you use for emission testing. (6) Span the FID with the C 3 8 (7) Introduce the CH 4 (8) Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the analyzer and to account for its response. (9) While the analyzer measures the CH 4 (10) For analyzers with multiple ranges, you need to perform the procedure in this paragraph (d) only on a single range. (11) Divide the mean measured concentration by the recorded span concentration of the CH 4 4 RF CH4[THC-FID] (12) You may determine the response factor as a function of molar water concentration using the following procedures and use this response factor to account for the CH 4 (i) Humidify the CH 4 (ii) Divide each mean measured CH 4 4 4 RF CH4[THC-FID]. (iii) Use the CH 4 (iv) Use this functional relationship to determine the response factor during an emission test. (e) THC FID CH 4 response verification. RF CH4[THC-FID] (1) Perform a CH 4 RF CH4[THC-FID] 4 RF CH4[THC-FID] (2) If RF CH4[THC-FID] RF CH4[THC-FID] (3) If RF CH4[THC-FID] (4) Determine a new RF CH4[THC-FID] RF CH4[THC-FID] (5) For analyzers with multiple ranges, you need to perform the procedure in this paragraph (e) only on a single range. (f) THC FID C 2 6 2 6 3 8 2 6 RF C2H6[THC-FID], 4 2 6 RF C2H6[THC-FID] 2 6 [73 FR 37308, June 30, 2008, as amended at 75 FR 23041, Apr. 30, 2010; 76 FR 57447, Sept. 15, 2011; 79 FR 23769, Apr. 28, 2014; 81 FR 74168, Oct. 25, 2016; 86 FR 34543, June 29, 2021; 89 FR 29798, Apr. 22, 2024] § 1065.362 Non-stoichiometric raw exhaust FID O 2 (a) Scope and frequency. 2 (b) Measurement principles. 2 2 (c) System requirements. 2 (d) Procedure. 2 (1) Select three span reference gases that contain a C 3 8 4 4 2 2 2 2 (2) Confirm that the FID analyzer meets all the specifications of § 1065.360. (3) Start and operate the FID analyzer as you would before an emission test. Regardless of the FID burner's air source during testing, use zero air as the FID burner's air source for this verification. (4) Zero the FID analyzer using the zero gas used during emission testing. (5) Span the FID analyzer using a span gas that you use during emission testing. (6) Check the zero response of the FID analyzer using the zero gas used during emission testing. If the mean zero response of 30 seconds of sampled data is within ±0.5% of the span reference value used in paragraph (d)(5) of this section, then proceed to the next step; otherwise restart the procedure at paragraph (d)(4) of this section. (7) Check the analyzer response using the span gas that has the minimum concentration of O 2 x O2minHC (8) Check the zero response of the FID analyzer using the zero gas used during emission testing. If the mean zero response of 30 seconds of stabilized sample data is within ±0.5% of the span reference value used in paragraph (d)(5) of this section, then proceed to the next step; otherwise restart the procedure at paragraph (d)(4) of this section. (9) Check the analyzer response using the span gas that has the average concentration of O 2 x O2avgHC (10) Check the zero response of the FID analyzer using the zero gas used during emission testing. If the mean zero response of 30 seconds of stabilized sample data is within ±0.5% of the span reference value used in paragraph (d)(5) of this section, proceed to the next step; otherwise restart the procedure at paragraph (d)(4) of this section. (11) Check the analyzer response using the span gas that has the maximum concentration of O 2 x O2maxHC (12) Check the zero response of the FID analyzer using the zero gas used during emission testing. If the mean zero response of 30 seconds of stabilized sample data is within ±0.5% of the span reference value used in paragraph (d)(5) of this section, then proceed to the next step; otherwise restart the procedure at paragraph (d)(4) of this section. (13) Calculate the percent difference between x O2maxHC x O2avgHC x O2minHC 2 (14) If the O 2 2 (i) Repeat the verification to determine if a mistake was made during the procedure. (ii) Select zero and span gases for emission testing that contain higher or lower O 2 (iii) Adjust FID burner air, fuel, and sample flow rates. Note that if you adjust these flow rates on a THC FID to meet the O 2 RF CH4 RF CH4 2 RF CH4 (iv) Repair or replace the FID and repeat the O 2 (v) Demonstrate that the deficiency does not adversely affect your ability to demonstrate compliance with the applicable emission standards. (15) For analyzers with multiple ranges, you need to perform the procedure in this paragraph (d) only on a single range. [70 FR 40516, July 13, 2005, as amended at 73 FR 37309, June 30, 2008; 79 FR 23770, Apr. 28, 2014]

\ § 1065.365 Nonmethane cutter penetration fractions and NMC FID response factors. (a) Scope and frequency. 4 4 2 6 (b) Measurement principles. 4 PF CH4, PF C2H6. (c) System requirements. PF C2H6 PF C2H6 PF C2H6 (d) Procedure for a FID calibrated with the NMC. (1) Select CH 4 2 6 4 2 6 4 (2) Start, operate, and optimize the NMC according to the manufacturer's instructions, including any temperature optimization. (3) Confirm that the FID analyzer meets all the specifications of § 1065.360. (4) Start and operate the FID analyzer according to the manufacturer's instructions. (5) Zero and span the FID with the NMC as you would during emission testing. Span the FID through the NMC by using CH 4 (6) Introduce the C 2 6 (7) Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the NMC and to account for the analyzer's response. (8) While the analyzer measures a stable concentration, record 30 seconds of sampled data. Calculate the arithmetic mean of the analytical gas mixture. (9) Calculate a reference concentration of C 2 6 2 6 1 2 6 RFPF C2H6[NMC-FID], 2 6 2 6 RFPF C2H6[NMC-FID] RFPF C2H6[NMC-FID] RFPF C2H6[NMC-FID] RFPF C2H6[NMC-FID] (10) For any gaseous-fueled engine, including dual-fuel and flexible-fuel engines, repeat the steps in paragraphs (d)(6) through (9) of this section, but with the CH 4 2 6 RFPF CH4[NMC-FID] CH4[NMC-FID] RFPF CH4[NMC-FID] (11) Use RFPF C2H6[NMC-FID] RFPF CH4[NMC-FID] (e) Procedure for a FID calibrated with propane, bypassing the NMC. 4 3 8 PF C2H6[NMC-FID] PF CH4[NMC-FID], (1) Select CH 4 2 6 4 2 6 2 6 4 (2) Start and operate the NMC according to the manufacturer's instructions, including any temperature optimization. (3) Confirm that the FID analyzer meets all the specifications of § 1065.360. (4) Start and operate the FID analyzer according to the manufacturer's instructions. (5) Zero and span the FID as you would during emission testing. Span the FID by bypassing the NMC and by using C 3 8 1 3 8 (6) Introduce the C 2 6 (7) Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the NMC and to account for the analyzer's response. (8) While the analyzer measures a stable concentration, record 30 seconds of sampled data. Calculate the arithmetic mean of the analytical gas mixture. (9) Reroute the flow path to bypass the NMC, introduce the C 2 6 (10) Divide the mean C 2 6 2 6 2 6 PF C2H6[NMC-FID]. (11) Repeat the steps in paragraphs (e)(6) through (10) of this section, but with the CH 4 2 6 4 PF CH4[NMC-FID]. (f) Procedure for a FID calibrated with CH 4, bypassing the NMC 4 2 6 RFPF C2H6[NMC-FID], 4 PF CH4[NMC-FID (1) Select CH 4 2 6 4 2 6 4 (2) Start and operate the NMC according to the manufacturer's instructions, including any temperature optimization. (3) Confirm that the FID analyzer meets all the specifications of § 1065.360. (4) Start and operate the FID analyzer according to the manufacturer's instructions. (5) Zero and span the FID as you would during emission testing. Span the FID by bypassing the NMC and by using CH 4 (6) Introduce the C 2 6 (7) Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the NMC and to account for the analyzer's response. (8) While the analyzer measures a stable concentration, record 30 seconds of sampled data. Calculate the arithmetic mean of the analytical gas mixture. (9) Divide the mean C 2 6 2 6 1 2 6 2 6 RFPF C2H6[NMC-FID]. 2 6 (10) Introduce the CH 4 (11) Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the NMC and to account for the analyzer's response. (12) While the analyzer measures a stable concentration, record 30 seconds of sampled data. Calculate the arithmetic mean of these data points. (13) Reroute the flow path to bypass the NMC, introduce the CH 4 (14) Divide the mean CH 4 4 4 PF CH4[NMC-FID]. 4 (g) Test gas humidification. 2 2 2 x H2Oref, x H2Oref 2 H2Oref U xH2O, (1) If the sample does not pass through a dryer during emission testing, generate at least five different H 2 (2) If the sample passes through a dryer during emission testing, humidify your test gas to an H 2 [89 FR 29799, Apr. 22, 2024] § 1065.366 Interference verification for FTIR analyzers. (a) Scope and frequency. 4 2 6 (b) Measurement principles. (c) System requirements. 4 (d) Procedure. 2 [81 FR 74168, Oct. 25, 2016, as amended at 89 FR 29801, Apr. 22, 2024] § 1065.369 H 2 2 (a) Scope and frequency. 2 2 (b) Measurement principles. 2 2 (c) System requirements. (d) Procedure. [79 FR 23770, Apr. 28, 2014, as amended at 89 FR 29801, Apr. 22, 2024] NO X 2 § 1065.370 CLD CO 2 2 (a) Scope and frequency. X 2 2 (b) Measurement principles. 2 2 X X 2 2 2 2 (c) System requirements. 2 2 2 2 (d) CO 2 quench verification procedure. 2 (1) Use PTFE or stainless steel tubing to make necessary connections. (2) Configure the gas divider such that nearly equal amounts of the span and diluent gases are blended with each other. (3) If the CLD analyzer has an operating mode in which it detects NO-only, as opposed to total NO X (4) Use a CO 2 2 (5) Use an NO span gas that meets the specifications of § 1065.750 and a concentration that is approximately twice the maximum NO concentration expected during emission testing. (6) Zero and span the CLD analyzer. Span the CLD analyzer with the NO span gas from paragraph (d)(5) of this section through the gas divider. Connect the NO span gas to the span port of the gas divider; connect a zero gas to the diluent port of the gas divider; use the same nominal blend ratio selected in paragraph (d)(2) of this section; and use the gas divider's output concentration of NO to span the CLD analyzer. Apply gas property corrections as necessary to ensure accurate gas division. (7) Connect the CO 2 (8) Connect the NO span gas to the diluent port of the gas divider. (9) While flowing NO and CO 2 2 x CO2act 2 2 (10) Measure the NO concentration downstream of the gas divider with the CLD analyzer. Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the transfer line and to account for analyzer response. While the analyzer measures the sample's concentration, record the analyzer's output for 30 seconds. Calculate the arithmetic mean concentration from these data, x NOmeas x NOmeas (11) Calculate the actual NO concentration at the gas divider's outlet, x NOact x CO2act (12) Use the values recorded according to this paragraph (d) and paragraph (e) of this section to calculate quench as described in § 1065.675. (e) H 2 quench verification procedure. 2 (1) Use PTFE or stainless steel tubing to make necessary connections. (2) If the CLD analyzer has an operating mode in which it detects NO-only, as opposed to total NO X (3) Use an NO span gas that meets the specifications of § 1065.750 and a concentration that is near the maximum concentration expected during emission testing. (4) Zero and span the CLD analyzer. Span the CLD analyzer with the NO span gas from paragraph (e)(3) of this section, record the span gas concentration as x NOdry (5) Create a humidified NO span gas by bubbling a NO gas that meets the specifications in § 1065.750 through distilled H 2 2 2 2 2 2 2 2 (6) Introduce the humidified NO test gas into the sample system. You may introduce it upstream or downstream of any sample dryer that is used during emission testing. Note that the sample dryer must meet the sample dryer verification check in § 1065.342. (7) Measure the mole fraction of H 2 x H2Omeas x 2Omeas x H2Omeas T dew p (8) Use good engineering judgment to prevent condensation in the transfer lines, fittings, or valves from the point where x H2Omeas x H2Omeas (9) Measure the humidified NO span gas concentration with the CLD analyzer. Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the transfer line and to account for analyzer response. While the analyzer measures the sample's concentration, record the analyzer's output for 30 seconds. Calculate the arithmetic mean of these data, x NOwet x NOwet (f) Corrective action. 2 2 (g) Exceptions. (1) You may omit this verification if you can show by engineering analysis that for your NO X 2 2 X X X X X X X X (2) You may use a NO X [73 FR 59328, Oct. 8, 2008, as amended at 73 FR 73789, Dec. 4, 2008; 75 FR 23041, Apr. 30, 2010; 76 FR 57447, Sept. 15, 2011; 79 FR 23771, Apr. 28, 2014; 81 FR 74168, Oct. 25, 2016; 86 FR 34545, June 29, 2021] § 1065.372 NDUV analyzer HC and H 2 (a) Scope and frequency. X 2 (b) Measurement principles. 2 X (c) System requirements. X 2 X (d) Procedure. (1) Start, operate, zero, and span the NO X (2) We recommend that you extract engine exhaust to perform this verification. Use a CLD that meets the specifications of subpart C of this part to quantify NO X (3) Upstream of any sample dryer, if one is used during testing, introduce the engine exhaust to the NDUV analyzer. (4) Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the transfer line and to account for analyzer response. (5) While all analyzers measure the sample's concentration, record 30 seconds of sampled data, and calculate the arithmetic means for the three analyzers. (6) Subtract the CLD mean from the NDUV mean. (7) Multiply this difference by the ratio of the flow-weighted mean HC concentration expected at the standard to the HC concentration measured during the verification. (8) The analyzer meets the interference verification of this section if the result of paragraph (d)(7) of this section meets the tolerance in paragraph (c) of this section. (e) Exceptions. (1) You may omit this verification if you can show by engineering analysis that for your NO X 2 X X X (2) You may use a NO X [70 FR 40516, July 13, 2005, as amended at 73 FR 37312, June 30, 2008; 76 FR 57447, Sept. 15, 2011; 89 FR 29801, Apr. 22, 2024] § 1065.375 Interference verification for N 2 (a) Scope and frequency. (b) Measurement principles. 2 (c) System requirements. (d) Procedure. (1) Start, operate, zero, and span the N 2 (2) Create a humidified test gas by bubbling a multi component span gas that incorporates the target interference species and meets the specifications in § 1065.750 through distilled H 2 2 2 2 (3) Introduce the humidified interference test gas into the sample system upstream or downstream of any sample dryer, if one is used during testing. (4) If the sample is not passed through a dryer during this verification test, measure the H 2 x H 2 O T dew p total x H 2 O 2 2 2 2 2 (5) If a sample dryer is not used in this verification test, use good engineering judgment to prevent condensation in the transfer lines, fittings, or valves from the point where x H 2 O x H 2 O (6) Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the transfer line and to account for analyzer response. (7) While the analyzer measures the sample's concentration, record its output for 30 seconds. Calculate the arithmetic mean of this data. When performed with all the gases simultaneously, this is the combined interference. (8) The analyzer meets the interference verification if the result of paragraph (d)(7) of this section meets the tolerance in paragraph (c) of this section. (9) You may also run interference procedures separately for individual interference species. If the concentrations of the interference species used are higher than the maximum levels expected during testing, you may scale down each observed interference value (the arithmetic mean of 30 second data described in paragraph (d)(7) of this section) by multiplying the observed interference by the ratio of the maximum expected concentration value to the actual value used during this procedure. You may run separate interference concentrations of H 2 2 2 2 [74 FR 56515, Oct. 30, 2009, as amended at 23771, Apr. 28, 2014; 81 FR 74168, Oct. 25, 2016; 86 FR 34545, June 29, 2021; 89 FR 29801, Apr. 22, 2024] § 1065.376 Chiller NO 2 (a) Scope and frequency. X 2 2 (b) Measurement principles. 2 X 2 2 2 2 X (c) System requirements. 2 2 (d) Procedure. (1) Instrument setup. (2) Equipment setup and data collection. X (ii) Select an NO 2 2 2 (iii) Overflow this calibration gas at the gas sampling system's probe or overflow fitting. Allow for stabilization of the total NO X (iv) Calculate the mean of 30 seconds of recorded total NO X x NOXref (v) Stop flowing the NO 2 (vi) Next saturate the sampling system by overflowing a dewpoint generator's output, set at a dewpoint of 50 °C, to the gas sampling system's probe or overflow fitting. Sample the dewpoint generator's output through the sampling system and chiller for at least 10 minutes until the chiller is expected to be removing a constant rate of H 2 (vii) Immediately switch back to overflowing the NO 2 x NOxref X X x NOxmeas (viii) Correct x NOxmeas x NOxdry 2 (3) Performance evaluation. x NOxdry x NOxref (e) Exceptions. (1) You may omit this verification if you can show by engineering analysis that for your NO X X X (2) You may use a chiller that you determine does not meet this verification, as long as you try to correct the problem and the measurement deficiency does not adversely affect your ability to show that engines comply with all applicable emission standards. [73 FR 37312, June 30, 2008, as amended at 79 FR 23771, Apr. 28, 2014] § 1065.377 Interference verification for NH 3 (a) Scope and frequency. (b) Measurement principles. 3 (c) System requirements. (d) Procedure. (1) Start, operate, zero, and span the NH 3 (2) Except as specified in paragraph (d)(9) of this section, select a multi-component span gas meeting the specification of § 1065.750 that incorporates the all the appropriate interference species. Use a humidity generator that meets the requirements in § 1065.750(a)(6) to humidify the span gas. If the sample does not pass through a dryer during emission testing, humidify your test gas to an H 2 2 (3) Introduce the humidified interference test gas into the sample system upstream or downstream of any sample dryer, if one is used during testing. (4) If the sample does not pass through a dryer during this verification test, measure the H 2 x H2O, T dew, p total, x H2O. 2 T dew, p total, x H2O x H2O 2 x H2O. (5) If the verification procedure does not include a sample dryer, use good engineering judgment to prevent condensation in the transfer lines, fittings, or valves between the point of x H2O (6) Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the transfer line and to account for analyzer response. (7) Operate the analyzer to measures the sample's NH 3 (8) The analyzer meets the interference verification if the result of paragraph (d)(7) of this section meets the tolerance in paragraph (c) of this section. (9) You may instead perform interference verification procedures separately for individual interference species. The interference verification specified in paragraph (c) of this section applies based on the sum of the interference values from separate interference species. If the concentration of any interference species used is higher than the maximum levels expected during testing, you may scale down each observed interference value by multiplying the observed interference value by the ratio of the maximum expected concentration value to the concentration in the span gas. You may run separate H 2 2 2 2 [89 FR 29801, Apr. 22, 2024] § 1065.378 NO 2 (a) Scope and frequency. X 2 2 (b) Measurement principles. 2 X 2 (c) System requirements. 2 2 2 (d) Procedure. 2 (1) Instrument setup. 2 (2) Equipment setup. 2 (3) Adjustments and data collection. (i) Set ozonator air off, turn ozonator power off, and set the analyzer to NO mode. Allow for stabilization, accounting only for transport delays and instrument response. (ii) Use an NO concentration that is representative of the peak total NO X 2 x NOref (iii) Turn on the ozonator O 2 2 x NOref x NO + O2mix (iv) Switch the ozonator on and adjust the ozone generation rate so the NO measured by the analyzer is 20 percent of x NOref 2 2 x NOmeas (v) Switch the NO X X X X x NOxmeas (vi) Switch off the ozonator but maintain gas flow through the system. The NO X X 2 X x NOx + O2mix (vii) Turn off the ozonator O 2 X X 2 X x NOxref x NOref (4) Performance evaluation. X (5) If the result is less than 95%, repair or replace the NO 2 (e) Exceptions. (1) You may omit this verification if you can show by engineering analysis that for your NO X X X (2) You may use a converter that you determine does not meet this verification, as long as you try to correct the problem and the measurement deficiency does not adversely affect your ability to show that engines comply with all applicable emission standards. (3) You may request to verify converter conversion efficiency using an NO 2 2 [70 FR 40516, July 13, 2005, as amended at 73 FR 37313, June 30, 2008; 73 FR 59330, Oct. 8, 2008; 76 FR 57447, Sept. 15, 2011; 89 FR 29802, Apr. 22, 2024] PM Measurements § 1065.390 PM balance verifications and weighing process verification. (a) Scope and frequency. (1) Independent verification of PM balance performance within 370 days before weighing any filter. (2) Zero and span the balance within 12 h before weighing any filter. (3) Verify that the mass determination of reference filters before and after a filter weighing session are less than a specified tolerance. (b) Independent verification. (c) Zeroing and spanning. (1) Use a manual procedure in which you zero the balance and span the balance with at least one calibration weight. If you normally use mean values by repeating the weighing process to improve the accuracy and precision of PM measurements, use the same process to verify balance performance. (2) You may use an automated procedure to verify balance performance. For example most balances have internal weights for automatically verifying balance performance. (d) Reference sample weighing. (1) Keep at least two samples of unused PM sample media (e.g., filters) in the PM-stabilization environment. Use these as references. If you collect PM with filters, select unused filters of the same material and size for use as references. You may periodically replace references, using good engineering judgment. (2) Stabilize references in the PM stabilization environment. Consider references stabilized if they have been in the PM-stabilization environment for a minimum of 30 min, and the PM-stabilization environment has been within the specifications of § 1065.190(d) for at least the preceding 60 min. (3) Exercise the balance several times with a reference sample. We recommend weighing ten samples without recording the values. (4) Zero and span the balance. Using good engineering judgment, place a test mass such as a calibration weight on the balance, then remove it. After spanning, confirm that the balance returns to a zero reading within the normal stabilization time. (5) Weigh each of the reference media (e.g., filters) and record their masses. We recommend using substitution weighing as described in § 1065.590(j). If you normally use mean values by repeating the weighing process to improve the accuracy and precision of the reference media (e.g., filter) mass, you must use mean values of sample media (e.g., filter) masses. (6) Record the balance environment dewpoint, ambient temperature, and atmospheric pressure. (7) Use the recorded ambient conditions to correct results for buoyancy as described in § 1065.690. Record the buoyancy-corrected mass of each of the references. (8) Subtract each reference media's (e.g., filter's) buoyancy-corrected reference mass from its previously measured and recorded buoyancy-corrected mass. (9) If any of the reference filters' observed mass changes by more than that allowed under this paragraph, you must invalidate all PM mass determinations made since the last successful reference media ( e.g. e.g. (10) If any of the reference masses change by more than that allowed under this paragraph (d), invalidate all PM results that were determined between the two times that the reference masses were determined. If you discarded reference PM sample media according to paragraph (d)(9) of this section, you must still have at least one reference mass difference that meets the criteria in this paragraph (d). Otherwise, you must invalidate all PM results that were determined between the two times that the reference media (e.g., filters) masses were determined. [73 FR 37313, June 30, 2008, as amended at 75 FR 23042, Apr. 30, 2010; 75 FR 68463, Nov. 8, 2010; 81 FR 74168, Oct. 25, 2016] § 1065.395 Inertial PM balance verifications. This section describes how to verify the performance of an inertial PM balance. (a) Independent verification. (b) Other verifications. Subpart E—Engine Selection, Preparation, and Maintenance § 1065.401 Test engine selection. While all engine configurations within a certified engine family must comply with the applicable standards in the standard-setting part, you need not test each configuration for certification. (a) Select an engine configuration within the engine family for testing, as follows: (1) Test the engine that we specify, whether we issue general guidance or give you specific instructions. (2) If we do not tell you which engine to test, follow any instructions in the standard-setting part. (3) If we do not tell you which engine to test and the standard-setting part does not include specifications for selecting test engines, use good engineering judgment to select the engine configuration within the engine family that is most likely to exceed an emission standard. (b) In the absence of other information, the following characteristics are appropriate to consider when selecting the engine to test: (1) Maximum fueling rates. (2) Maximum loads. (3) Maximum in-use speeds. (4) Highest sales volume. (c) For our testing, we may select any engine configuration within the engine family. § 1065.405 Test engine preparation and maintenance. This part 1065 describes how to test engines for a variety of purposes, including certification testing, production-line testing, and in-use testing. Depending on which type of testing is being conducted, different preparation and maintenance requirements apply for the test engine. (a) If you are testing an emission-data engine for certification, make sure it is built to represent production engines, consistent with paragraph (f) of this section. (1) This includes governors that you normally install on production engines. Production engines should also be tested with their installed governors. If your engine is equipped with multiple user-selectable governor types and if the governor does not manipulate the emission control system ( i.e., (2) In certain circumstances, you may incorporate test cell components to simulate an in-use configuration, consistent with good engineering judgment. For example, §§ 1065.122 and 1065.125 allow the use of test cell components to represent engine cooling and intake air systems. (3) The provisions in § 1065.110(e) also apply to emission-data engines for certification. (4) For engines using SCR, use any size DEF tank and fuel tank. We may require you to give us a production-type DEF tank, including any associated sensors, for our testing. (b) We may set adjustable parameters to any value in the valid range, and you are responsible for controlling emissions over the full valid range. For each adjustable parameter, if the standard-setting part has no unique requirements and if we have not specified a value, use good engineering judgment to select the most common setting. If information on the most common setting is not available, select the setting representing the engine's original shipped configuration. If information on the most common and original settings is not available, set the adjustable parameter in the middle of the valid range. (c) Testing generally occurs only after the test engine has undergone a stabilization step (or in-use operation). If the engine has not already been stabilized, run the test engine, with all emission control systems operating, long enough to stabilize emission levels. Note that you must generally use the same stabilization procedures for emission-data engines for which you apply the same deterioration factors so low-hour emission-data engines are consistent with the low-hour engine used to develop the deterioration factor. (1) Unless otherwise specified in the standard-setting part, you may consider emission levels stable without measurement after 50 h of operation. If the engine needs less operation to stabilize emission levels, record your reasons and the methods for doing this, and give us these records if we ask for them. If the engine will be tested for certification as a low-hour engine, see the standard-setting part for limits on testing engines to establish low-hour emission levels. (2) You may stabilize emissions from a catalytic exhaust aftertreatment device by operating it on a different engine, consistent with good engineering judgment. Note that good engineering judgment requires that you consider both the purpose of the test and how your stabilization method will affect the development and application of deterioration factors. For example, this method of stabilization is generally not appropriate for production engines. We may also allow you to stabilize emissions from a catalytic exhaust aftertreatment device by operating it on an engine-exhaust simulator. (d) Record any maintenance, modifications, parts changes, diagnostic or emissions testing and document the need for each event. You must provide this information if we request it. (e) For accumulating operating hours on your test engines, select engine operation that represents normal in-use operation for the engine family. (f) If your engine will be used in a vehicle equipped with a canister for storing evaporative hydrocarbons for eventual combustion in the engine and the test sequence involves a cold-start or hot-start duty cycle, attach a canister to the engine before running an emission test. You may omit using an evaporative canister for any hot-stabilized duty cycles. You may request to omit using an evaporative canister during testing if you can show that it would not affect your ability to show compliance with the applicable emission standards. You may operate the engine without an installed canister for service accumulation. Prior to an emission test, use the following steps to precondition a canister and attach it to your engine: (1) Use a canister and plumbing arrangement that represents the in-use configuration of the largest capacity canister in all expected applications. (2) Precondition the canister as described in 40 CFR 86.132-96(j). (3) Connect the canister's purge port to the engine. (4) Plug the canister port that is normally connected to the fuel tank. (g) This paragraph (g) defines the components that are considered to be part of the engine for laboratory testing. See § 1065.110 for provisions related to system boundaries with respect to work inputs and outputs. (1) This paragraph (g)(1) describes certain criteria for considering a component to be part of the test engine. The criteria are intended to apply broadly, such that a component would generally be considered part of the engine in cases of uncertainty. Except as specified in paragraph (g)(2) of this section, an engine-related component meeting both the following criteria is considered to be part of the test engine for purposes of testing and for stabilizing emission levels, preconditioning, and measuring emission levels: (i) The component directly affects the functioning of the engine, is related to controlling emissions, or transmits engine power. This would include engine cooling systems, engine controls, and transmissions. (ii) The component is covered by the applicable certificate of conformity. For example, this criterion would typically exclude radiators not described in an application for certification. (2) This paragraph (g)(2) applies for engine-related components that meet the criteria of paragraph (g)(1) of this section, but that are part of the laboratory setup or are used for other engines. Such components are considered to be part of the test engine for preconditioning, but not for engine stabilization. For example, if you test your engines using the same laboratory exhaust tubing for all tests, there would be no restrictions on the number of test hours that could be accumulated with the tubing, but it would need to be preconditioned separately for each engine. [79 FR 23772, Apr. 28, 2014, as amended at 88 FR 4675, Jan. 24, 2023] § 1065.410 Maintenance limits for stabilized test engines. (a) After you stabilize the test engine's emission levels, you may do maintenance as allowed by the standard-setting part. However, you may not do any maintenance based on emission measurements from the test engine (i.e., unscheduled maintenance). (b) For any critical emission-related maintenance—other than what we specifically allow in the standard-setting part—you must completely test an engine for emissions before and after doing any maintenance that might affect emissions, unless we waive this requirement. (c) If you inspect an engine, keep a record of the inspection and update your application for certification to document any changes that result. You may use any kind of equipment, instrument, or tool that is available at dealerships and other service outlets to identify malfunctioning components or perform maintenance. You may inspect using electronic tools or internal engine systems to monitor engine performance, but only if the information is readable without specialized equipment. (d) You may repair defective parts from a test engine if they are unrelated to emission control. You must ask us to approve repairs that might affect the engine's emission controls. If we determine that a part failure, system malfunction, or associated repair makes the engine's emission controls unrepresentative of production engines, you may not use it as an emission-data engine. Also, if your test engine has a major mechanical failure that requires you to take it apart, you may no longer use it as an emission-data engine. [70 FR 40516, July 13, 2005, as amended at 73 FR 37314, June 30, 2008; 79 FR 23773, Apr. 28, 2014; 80 FR 9118, Feb. 19, 2015; 86 FR 34545, June 29, 2021; 88 FR 4675, Jan. 24, 2023] § 1065.415 Durability demonstration. If the standard-setting part requires durability testing, you must accumulate service in a way that represents how you expect the engine to operate in use. You may accumulate service hours using an accelerated schedule, such as through continuous operation or by using duty cycles that are more aggressive than in-use operation, subject to any pre-approval requirements established in the applicable standard-setting part. (a) Maintenance. (1) You may perform scheduled maintenance that you recommend to operators, but only if it is consistent with the standard-setting part's restrictions. (2) You may perform additional maintenance only as specified in § 1065.410 or allowed by the standard-setting part. (b) Emission measurements. [70 FR 40516, July 13, 2005, as amended at 73 FR 37315, June 30, 2008] Subpart F—Performing an Emission Test Over Specified Duty Cycles § 1065.501 Overview. (a) Use the procedures detailed in this subpart to measure engine emissions over a specified duty cycle. Refer to subpart J of this part for field test procedures that describe how to measure emissions during in-use engine operation. Refer to subpart L of this part for measurement procedures for testing related to standards other than brake-specific emission standards. This section describes how to— (1) Map your engine, if applicable, by recording specified speed and torque data, as measured from the engine's primary output shaft. (2) Transform normalized duty cycles into reference duty cycles for your engine by using an engine map. (3) Prepare your engine, equipment, and measurement instruments for an emission test. (4) Perform pre-test procedures to verify proper operation of certain equipment and analyzers. (5) Record pre-test data. (6) Start or restart the engine and sampling systems. (7) Sample emissions throughout the duty cycle. (8) Record post-test data. (9) Perform post-test procedures to verify proper operation of certain equipment and analyzers. (10) Weigh PM samples. (b) Unless we specify otherwise, you may control the regeneration timing of infrequently regenerated aftertreatment devices such as diesel particulate filters using good engineering judgment. You may control the regeneration timing using a sequence of engine operating conditions or you may initiate regeneration with an external regeneration switch or other command. This provision also allows you to ensure that a regeneration event does not occur during an emission test. (c) An emission test generally consists of measuring emissions and other parameters while an engine follows one or more duty cycles that are specified in the standard-setting part. There are two general types of duty cycles: (1) Transient cycles. (i) A cold-start transient cycle where you start to measure emissions just before starting an engine that has not been warmed up. (ii) A hot-start transient cycle where you start to measure emissions just before starting a warmed-up engine. (iii) A hot running transient cycle where you start to measure emissions after an engine is started, warmed up, and running. (2) Steady-state cycles. (i) Discrete-mode cycles. (A) Use good engineering judgment to determine the time required to stabilize the engine. You may make this determination before starting the test based on prior experience, or you may make this determination in real time based an automated stability criteria. If needed, you may continue to operate the engine after reaching stability to get laboratory equipment ready for sampling. (B) Collect PM on separate PM sample media for each mode. (C) The minimum sample time is 60 seconds. We recommend that you sample both gaseous and PM emissions over the same test interval. If you sample gaseous and PM emissions over different test intervals, there must be no change in engine operation between the two test intervals. These two test intervals may completely or partially overlap, they may run consecutively, or they may be separated in time. (ii) Ramped-modal cycles. (d) Other subparts in this part identify how to select and prepare an engine for testing (subpart E), how to perform the required engine service accumulation (subpart E), and how to calculate emission results (subpart G). (e) Subpart J of this part describes how to perform field testing. [79 FR 23773, Apr. 28, 2014, as amended at 88 FR 4676, Jan. 24, 2023] § 1065.510 Engine mapping. (a) Applicability, scope, and frequency. (1) If you have not performed an initial engine map. (2) If the atmospheric pressure near the engine's air inlet is not within ±5 kPa of the atmospheric pressure recorded at the time of the last engine map. (3) If the engine or emission-control system has undergone changes that might affect maximum torque performance. This includes changing the configuration of auxiliary work inputs and outputs. (4) If you capture an incomplete map on your first attempt or you do not complete a map within the specified time tolerance. You may repeat mapping as often as necessary to capture a complete map within the specified time. (b) Mapping variable-speed engines. (1) Record the atmospheric pressure. (2) Warm up the engine by operating it. We recommend operating the engine at any speed and at approximately 75% of its expected maximum power. Continue the warm-up until the engine coolant, block, lubricating oil, or head absolute temperature is within ±2% of its mean value for at least 2 min or until the engine thermostat controls engine temperature. (3) Operate the engine at its warm idle speed as follows: (i) For engines with a low-speed governor, set the operator demand to minimum, use the dynamometer or other loading device to target a torque of zero or the lowest idle load that you will use for cycle generation on the engine's primary output shaft, and allow the engine to govern the speed. If the idle load is a function of engine speeds ( e.g., (ii) For engines without a low-speed governor, operate the engine at warm idle speed from paragraph (f)(2) of this section and zero torque or the lowest warm idle torque that you will use for cycle generation on the engine's primary output shaft. You may use the dynamometer to control either torque or speed and manipulate the operator demand to control the other parameter. (4) Operate the engine at the minimum mapped speed. A minimum mapped speed equal to (95 ± 1)% of its warm idle speed determined in paragraph (b)(3) of this section may be used for any engine or test. A higher minimum mapped speed may be used if all the duty cycles that the engine is subject to have a minimum reference speed higher than the warm idle speed determined in paragraph (b)(3) of this section. In this case you may use a minimum mapped speed equal to (95 ± 1)% of the lowest minimum reference speed in all the duty cycles the engine is subject to. Set operator demand to maximum and control engine speed at this minimum mapped speed for at least 15 seconds. Set operator demand to maximum and control engine speed at (95 ± 1)% of its warm idle speed determined in paragraph (b)(3)(i) of this section for at least 15 seconds. (5) Perform a continuous or discrete engine map as described in paragraph (b)(5)(i) or (ii) of this section. A continuous engine map may be used for any engine. A discrete engine map may be used for engines subject only to steady-state duty cycles. Use linear interpolation between the series of points generated by either of these maps to determine intermediate torque values. Use the series of points generated by either of these maps to generate the power map as described in paragraph (e) of this section. (i) For continuous engine mapping, begin recording mean feedback speed and torque at 1 Hz or more frequently and increase speed at a constant rate such that it takes (4 to 6) min to sweep from the minimum mapped speed described in paragraph (b)(4) of this section to the check point speed described in paragraph (b)(5)(iii) of this section. Use good engineering judgment to determine when to stop recording data to ensure that the sweep is complete. In most cases, this means that you can stop the sweep at any point after the power falls to 50% of the maximum value. (ii) For discrete engine mapping, select at least 20 evenly spaced setpoints from the minimum mapped speed described in paragraph (b)(4) of this section to the check point speed described in paragraph (b)(5)(iii) of this section. At each setpoint, stabilize speed and allow torque to stabilize. We recommend that you stabilize an engine for at least 15 seconds at each setpoint and record the mean feedback speed and torque of the last (4 to 6) seconds. Record the mean speed and torque at each setpoint. (iii) The check point speed of the map is the highest speed above maximum power at which 50% of maximum power occurs. If this speed is unsafe or unachievable ( e.g., (iv) Note that under § 1065.10(c)(1) we may allow you to disregard portions of the map when selecting maximum test speed if the specified procedure would result in a duty cycle that does not represent in-use operation. (6) Determine warm high-idle speed for engines with a high-speed governor. You may skip this if the engine is not subject to transient testing with a duty cycle that includes reference speed values above 100%. You may use a manufacturer-declared warm high-idle speed if the engine is electronically governed. For engines with a high-speed governor that regulates speed by disabling and enabling fuel or ignition at two manufacturer-specified speeds, declare the middle of this specified speed range as the warm high-idle speed. You may alternatively measure warm high-idle speed using the following procedure: (i) Run an operating point targeting zero torque. (A) Set operator demand to maximum and use the dynamometer to target zero torque on the engine's primary output shaft. (B) Wait for the engine governor and dynamometer to stabilize. We recommend that you stabilize for at least 15 seconds. (C) Record 1 Hz means of the feedback speed and torque for at least 30 seconds. You may record means at a higher frequency as long as there are no gaps in the recorded data. For engines with a high-speed governor that regulates speed by disabling and enabling fuel or ignition, you may need to extend this stabilization period to include at least one disabling event at the higher speed and one enabling event at the lower speed. (D) Determine if the feedback speed is stable over the recording period. The feedback speed is considered stable if all the recorded 1 Hz means are within ±2% of the mean feedback speed over the recording period. If the feedback speed is not stable because of the dynamometer, void the results and repeat measurements after making any necessary corrections. You may void and repeat the entire map sequence, or you may void and replace only the results for establishing warm high-idle speed; use good engineering judgment to warm-up the engine before repeating measurements. (E) If the feedback speed is stable, use the mean feedback speed over the recording period as the measured speed for this operating point. (F) If the feedback speed is not stable because of the engine, determine the mean as the value representing the midpoint between the observed maximum and minimum recorded feedback speed. (G) If the mean feedback torque over the recording period is within (0 ± 1)% of T maxmapped, (ii) Run a second operating point targeting a positive torque. Follow the same procedure in paragraphs (b)(6)(i)(A) through (F) of this section, except that the dynamometer is set to target a torque equal to the mean feedback torque over the recording period from the previous operating point plus 20% of T max mapped. (iii) Use the mean feedback speed and torque values from paragraphs (b)(6)(i) and (ii) of this section to determine the warm high-idle speed. If the two recorded speed values are the same, use that value as the warm high-idle-speed. Otherwise, use a linear equation passing through these two speed-torque points and extrapolate to solve for the speed at zero torque and use this speed intercept value as the warm high-idle speed. (iv) You may use a manufacturer-declared T max T max mapped. (7) This paragraph (b)(7) describes how to collect additional data to determine warm idle speed(s) for cycle generation if your engine has a low-speed governor. You may omit this paragraph (b)(7) if you use the option to declare a warm idle speed in paragraph (f)(3)(iv) of this section, or if you identify only one idle load and one user-adjustable idle speed setpoint under paragraph (b)(3)(i) of this section. Collect additional data to determine warm idle speed(s) using one of the following options: (i) For each idle load ( e.g., (ii) You may map the idle governor at multiple torque levels and use this map to determine the warm idle speed(s) at any idle load within the range of this map. For cases where the idle torque is a function of engine speeds ( e.g., (8) This paragraph (b)(8) describes how to collect additional data to determine warm idle speed(s) for cycle generation if your engine has a low-speed governor and a user-adjustable idle speed setpoint and you need to generate cycles for tests with a different setpoint from the setpoint used in this mapping procedure. You may omit this paragraph (b)(8) if you use the option to declare a warm idle speed in paragraph (f)(3)(iv) of this section. Collect additional data using paragraph (b)(7) of this section to determine the warm idle speed for each setpoint for use in generating cycles. Record the warm idle speed and torque for each setpoint. (c) Negative torque mapping. i.e., (1) Multiply the positive torques from your map by −40%. Use linear interpolation to determine intermediate values. (2) Map the amount of negative torque required to motor the engine by repeating paragraph (b) of this section with minimum operator demand, as applicable. You may start the negative torque map at either the minimum or maximum speed from paragraph (b) of this section. (3) Determine the amount of negative torque required to motor the engine at the following two points near the ends of the engine's speed range. Operate the engine at these two points at minimum operator demand. Use linear interpolation to determine intermediate values. (i) Low-speed point. (ii) High-speed point. n hi (4) For engines with an electric hybrid system, map the negative torque required to motor the engine and absorb any power delivered from the RESS by repeating paragraph (g)(2) of this section with minimum operator demand, stopping the sweep to discharge the RESS when the absolute instantaneous power measured from the RESS drops below the expected maximum absolute power from the RESS by more than 2% of total system maximum power (including engine motoring and RESS power) as determined from mapping the negative torque. (5) For engines with an electric hybrid system, map the negative torque required to motor the engine by repeating paragraph (b) of this section with minimum operator demand and a fully charged RESS or with the hybrid system disabled, such that it doesn't affect the motoring torque. You may start the negative torque map at either the minimum or maximum speed from paragraph (b) of this section. (d) Mapping constant-speed engines. e.g., (1) Record the atmospheric pressure. (2) Warm up the engine by operating it. We recommend operating the engine at approximately 75% of the engine's expected maximum power. Continue the warm-up until the engine coolant, block, or head absolute temperature is within ±2% of its mean value for at least 2 min or until the engine thermostat controls engine temperature. (3) You may operate the engine with a production constant-speed governor or simulate a constant-speed governor by controlling engine speed with an operator demand control system described in § 1065.110. Use either isochronous or speed-droop governor operation, as appropriate. (4) With the governor or simulated governor controlling speed using operator demand, operate the engine at the no-load, or minimum achievable load, governed speed (at high speed, not low idle) for at least 15 seconds. (5) Record at 1 Hz the mean of feedback speed and torque. Use the dynamometer to increase torque at a constant rate. Unless the standard-setting part specifies otherwise, complete the map such that it takes (2 to 4) min to sweep from no-load governed speed to the speed below maximum mapped power at which the engine develops 90% of maximum mapped power. You may map your engine to lower speeds. Stop recording after you complete the sweep. Use this series of speeds and torques to generate the power map as described in paragraph (e) of this section. (i) For constant-speed engines subject only to steady-state testing, you may perform an engine map by using a series of discrete torques. Select at least five evenly spaced torque setpoints from no-load to 80% of the manufacturer-declared test torque or to a torque derived from your published maximum power level if the declared test torque is unavailable. Starting at the 80% torque point, select setpoints in 2.5% or smaller intervals, stopping at the endpoint torque. The endpoint torque is defined as the first discrete mapped torque value greater than the torque at maximum observed power where the engine outputs 90% of the maximum observed power; or the torque when engine stall has been determined using good engineering judgment ( i.e., (ii) For any constant-speed engine, you may perform an engine map with a continuous torque sweep by continuing to record the mean feedback speed and torque at 1 Hz or more frequently. Use the dynamometer to increase torque. Increase the reference torque at a constant rate from no-load to the endpoint torque as defined in paragraph (d)(5)(i) of this section. You may continue mapping at higher torque setpoints. Unless the standard-setting part specifies otherwise, target a torque sweep rate equal to the manufacturer-declared test torque (or a torque derived from your published power level if the declared test torque is not known) divided by 180 seconds. Stop recording after you complete the sweep. Verify that the average torque sweep rate over the entire map is within ±7% of the target torque sweep rate. Use linear interpolation to determine intermediate values from this series of mean feedback speed and torque values. Use this series of mean feedback speeds and torques to generate the power map as described in paragraph (e) of this section. (iii) For any isochronous governed (no speed droop) constant-speed engine, you may map the engine with two points as described in this paragraph (d)(5)(iii). After stabilizing at the no-load, or minimum achievable load, governed speed in paragraph (d)(4) of this section, record the mean feedback speed and torque. Continue to operate the engine with the governor or simulated governor controlling engine speed using operator demand and control the dynamometer to target a speed of 99.5% of the recorded mean no-load governed speed. Allow speed and torque to stabilize. Record the mean feedback speed and torque. Record the target speed. The absolute value of the speed error (the mean feedback speed minus the target speed) must be no greater than 0.1% of the recorded mean no-load governed speed. From this series of two mean feedback speed and torque values, use linear interpolation to determine intermediate values. Use this series of two mean feedback speeds and torques to generate a power map as described in paragraph (e) of this section. Note that the measured maximum test torque as determined in § 1065.610(b)(1) will be the mean feedback torque recorded on the second point. (e) Power mapping. (f) Measured and declared speeds, torques, and power. (1) Measured speeds and torques. (i) Measured maximum test speed for variable-speed engines according to § 1065.610. (ii) Measured maximum test torque for constant-speed engines according to § 1065.610. (iii) Measured “A”, “B”, and “C” speeds for variable-speed engines according to § 1065.610. (iv) Measured intermediate speed for variable-speed engines according to § 1065.610. (v) For variable-speed engines with a low-speed governor, measure warm idle speed(s) according to paragraph (b) of this section and use this (these) speed(s) for cycle generation in § 1065.512. For engines with no low-speed governor, instead use the manufacturer-declared warm idle speed from paragraph (f)(2) of this section. (2) Required declared speeds. i.e., (3) Optional declared speeds. (i) You may use a declared value for maximum test speed for variable-speed engines if it is within (97.5 to 102.5)% of the corresponding measured value. You may use a higher declared speed if the length of the “vector” at the declared speed is within 2% of the length of the “vector” at the measured value. The term vector refers to the square root of the sum of normalized engine speed squared and the normalized full-load power (at that speed) squared, consistent with the calculations in § 1065.610. (ii) You may use a declared value for intermediate, “A”, “B”, or “C” speeds for steady-state tests if the declared value is within (97.5 to 102.5)% of the corresponding measured value. (iii) For electronically governed variable-speed engines, you may use a declared warm high-idle speed for calculating the alternate maximum test speed as specified in § 1065.610. (iv) For electronically governed variable-speed engines with an isochronous low-speed governor ( i.e., e.g., (4) Required declared torque. (5) Optional declared torques. (i) For variable-speed engines you may declare a maximum torque over the engine operating range. You may use the declared value for measuring warm high-idle speed as specified in this section. (ii) For constant-speed engines you may declare a maximum test torque. You may use the declared value for cycle generation if it is within (95 to 100)% of the measured value. (iii) For variable-speed engines, you may declare a nonzero torque for idle operation that represents in-use operation. For example, if your engine is connected to a hydrostatic transmission with a minimum torque even when all the driven hydraulic actuators and motors are stationary and the engine is at idle, you may use this minimum torque as the declared value. As another example, if your engine is connected to a vehicle or machine with accessories, you may use a declared torque corresponding to operation with those accessories. You may specify a combination of torque and power as described in paragraph (f)(6) of this section. Use this option when the idle loads ( e.g., (iv) For constant-speed engines, you may declare a warm minimum torque that represents in-use operation. For example, if your engine is typically connected to a machine that does not operate below a certain minimum torque, you may use this minimum torque as the declared value and use it for cycle generation. (6) Optional declared power. i.e., (g) Mapping variable-speed engines with an electric hybrid system. (1) Prepare the engine for mapping by either deactivating the hybrid system or by operating the engine as specified in paragraph (b)(4) of this section and remaining at this condition until the rechargeable energy storage system (RESS) is depleted. Once the hybrid has been disabled or the RESS is depleted, perform an engine map as specified in paragraph (b)(5) of this section. If the RESS was depleted instead of deactivated, ensure that instantaneous power from the RESS remains less than 2% of the instantaneous measured power from the engine (or engine-hybrid system) at all engine speeds. (2) The purpose of the mapping procedure in this paragraph (g) is to determine the maximum torque available at each speed, such as what might occur during transient operation with a fully charged RESS. Use one of the following methods to generate a hybrid-active map: (i) Perform an engine map by using a series of continuous sweeps to cover the engine's full range of operating speeds. Prepare the engine for hybrid-active mapping by ensuring that the RESS state of charge is representative of normal operation. Perform the sweep as specified in paragraph (b)(5)(i) of this section, but stop the sweep to charge the RESS when the power measured from the RESS drops below the expected maximum power from the RESS by more than 2% of total system power (including engine and RESS power). Unless good engineering judgment indicates otherwise, assume that the expected maximum power from the RESS is equal to the measured RESS power at the start of the sweep segment. For example, if the 3-second rolling average of total engine-RESS power is 200 kW and the power from the RESS at the beginning of the sweep segment is 50 kW, once the power from the RESS reaches 46 kW, stop the sweep to charge the RESS. Note that this assumption is not valid where the hybrid motor is torque-limited. Calculate total system power as a 3-second rolling average of instantaneous total system power. After each charging event, stabilize the engine for 15 seconds at the speed at which you ended the previous segment with operator demand set to maximum before continuing the sweep from that speed. Repeat the cycle of charging, mapping, and recharging until you have completed the engine map. You may shut down the system or include other operation between segments to be consistent with the intent of this paragraph (g)(2)(i). For example, for systems in which continuous charging and discharging can overheat batteries to an extent that affects performance, you may operate the engine at zero power from the RESS for enough time after the system is recharged to allow the batteries to cool. Use good engineering judgment to smooth the torque curve to eliminate discontinuities between map intervals. (ii) Perform an engine map by using discrete speeds. Select map setpoints at intervals defined by the ranges of engine speed being mapped. From 95% of warm idle speed to 90% of the expected maximum test speed, select setpoints that result in a minimum of 13 equally spaced speed setpoints. From 90% to 110% of expected maximum test speed, select setpoints in equally spaced intervals that are nominally 2% of expected maximum test speed. Above 110% of expected maximum test speed, select setpoints based on the same speed intervals used for mapping from 95% warm idle speed to 90% maximum test speed. You may stop mapping at the highest speed above maximum power at which 50% of maximum power occurs. We refer to the speed at 50% power as the check point speed as described in paragraph (b)(5)(iii) of this section. Stabilize engine speed at each setpoint, targeting a torque value at 70% of peak torque at that speed without hybrid-assist. Make sure the engine is fully warmed up and the RESS state of charge is within the normal operating range. Snap the operator demand to maximum, operate the engine there for at least 10 seconds, and record the 3-second rolling average feedback speed and torque at 1 Hz or higher. Record the peak 3-second average torque and 3-second average speed at that point. Use linear interpolation to determine intermediate speeds and torques. Follow § 1065.610(a) to calculate the maximum test speed. Verify that the measured maximum test speed falls in the range from 92 to 108% of the estimated maximum test speed. If the measured maximum test speed does not fall in this range, repeat the map using the measured value of maximum test speed. (h) Other mapping procedures. [73 FR 37315, June 30, 2008, as amended at 73 FR 59330, Oct. 8, 2008; 75 FR 23042, Apr. 30, 2010; 76 FR 57448, Sept. 15, 2011; 79 FR 23773, Apr. 28, 2014; 81 FR 74169, Oct. 25, 2016; 86 FR 34545, June 29, 2021; 88 FR 4676, Jan. 24, 2023; 89 FR 29802, Apr. 22, 2024; 89 FR 51237, June 17, 2024] § 1065.512 Duty cycle generation. (a) Generate duty cycles according to this section if the standard-setting part requires engine mapping to generate a duty cycle for your engine configuration. The standard-setting part generally defines applicable duty cycles in a normalized format. A normalized duty cycle consists of a sequence of paired values for speed and torque or for speed and power. (b) Transform normalized values of speed, torque, and power using the following conventions: (1) Engine speed for variable-speed engines. nidle, ntest, nref. (i) While running an engine where the ECM broadcasts an enhanced-idle speed that is above the denormalized speed, use the broadcast speed as the reference speed. Use these new reference points for duty-cycle validation. This does not affect how you determine denormalized reference torque in paragraph (b)(2) of this section. (ii) If an ECM broadcast signal is not available, perform one or more practice cycles to determine the enhanced-idle speed as a function of cycle time. Generate the reference cycle as you normally would but replace any reference speed that is lower than the enhanced-idle speed with the enhanced-idle speed. This does not affect how you determine denormalized reference torque in paragraph (b)(2) of this section. (2) Engine torque for variable-speed engines. T ref T ref T ref (3) Engine torque for constant-speed engines. T test T ref T ref T ref (4) Engine power. f ntest P ref (5) Ramped-modal cycles. (c) For variable-speed engines, command reference speeds and torques sequentially to perform a duty cycle. Issue speed and torque commands at a frequency of at least 5 Hz for transient cycles and at least 1 Hz for steady-state cycles ( i.e. (d) For constant-speed engines, operate the engine with the same production governor you used to map the engine in § 1065.510 or simulate the in-use operation of a governor the same way you simulated it to map the engine in § 1065.510. Command reference torque values sequentially to perform a duty cycle. Issue torque commands at a frequency of at least 5 Hz for transient cycles and at least 1 Hz for steady-state cycles ( i.e. (e) You may perform practice duty cycles with the test engine to optimize operator demand and dynamometer controls to meet the cycle-validation criteria specified in § 1065.514. [73 FR 37317, June 30, 2008, as amended at 79 FR 23774, Apr. 28, 2014; 86 FR 34546, June 29, 2021; 88 FR 4678, Jan. 24, 2023; 89 FR 29805, Apr. 22, 2024] § 1065.514 Cycle-validation criteria for operation over specified duty cycles. Validate the execution of your duty cycle according to this section unless the standard-setting part specifies otherwise. This section describes how to determine if the engine's operation during the test adequately matched the reference duty cycle. This section applies only to speed, torque, and power from the engine's primary output shaft. Other work inputs and outputs are not subject to cycle-validation criteria. You must compare the original reference duty cycle points generated as described in § 1065.512 to the corresponding feedback values recorded during the test. You may compare reference duty cycle points recorded during the test to the corresponding feedback values recorded during the test as long as the recorded reference values match the original points generated in § 1065.512. The number of points in the validation regression are based on the number of points in the original reference duty cycle generated in § 1065.512. For example if the original cycle has 1199 reference points at 1 Hz, then the regression will have up to 1199 pairs of reference and feedback values at the corresponding moments in the test. The feedback speed and torque signals may be filtered—either in real-time while the test is run or afterward in the analysis program. Any filtering that is used on the feedback signals used for cycle validation must also be used for calculating work. Feedback signals for control loops may use different filtering. (a) Testing performed by EPA. (b) Testing performed by manufacturers. (c) Time-alignment. (d) Omitting additional points. Table 1 to Paragraph ( d When operator demand is at its . . . you may omit . . . if . . . For reference duty cycles that are specified in terms of speed and torque ( ) minimum power and torque T ref minimum power and speed f nref T ref T ref T max mapped T T ref T max mapped minimum power and speed f nref a T ref minimum power and either torque or speed f n f nref T T ref f n f nref T T ref + T max mapped maximum power and either torque or speed f n f nref T T ref f n f nref T T ref T max mapped For reference duty cycles that are specified in terms of speed and power ( ) minimum power and torque P ref minimum power and speed f nref P ref P ref P max mapped P P ref P max mapped minimum power and either torque or speed f n f nref P P ref f n f nref P P ref P max mapped maximum power and either torque or speed f n f nref P P f n f nref P P ref P max mapped a (e) Statistical parameters. (1) Slopes for feedback speed, a 1fn a 1T a 1P (2) Intercepts for feedback speed, a 0fn a 0T a 0P (3) Standard error of the estimate for feedback speed, SEEfn, feedback torque, SEET, and feedback power SEEP. (4) Coefficients of determination for feedback speed, r 2 fn r 2 T r 2 P (f) Cycle-validation criteria. (1) For variable-speed engines, apply all the statistical criteria in Table 2 of this section. (2) For constant-speed engines, apply only the statistical criteria for torque in Table 2 of this section. (3) For discrete-mode steady-state testing, apply cycle-validation criteria by treating the sampling periods from the series of test modes as a continuous sampling period, analogous to ramped-modal testing and apply statistical criteria as described in paragraph (f)(1) or (2) of this section. Note that if the gaseous and particulate test intervals are different periods of time, separate validations are required for the gaseous and particulate test intervals. Table 2 follows: Table 2 of § 1065.514—Default Statistical Criteria for Validating Duty Cycles Parameter Speed Torque Power Slope, a 1 0.950 ≤ a 1 0.830 ≤ a 1 0.830 ≤ a 1 Absolute value of intercept, | a 0 ≤ 10% of warm idle ≤ 2% of maximum mapped torque ≤ 2% of maximum mapped power. Standard error of the estimate, SEE ≤ 5% of maximum test speed ≤ 10% of maximum mapped torque ≤ 10% of maximum mapped power. Coefficient of determination, r 2 ≥ 0.970 ≥ 0.850 ≥ 0.910. [73 FR 37318, June 30, 2008, as amended at 73 FR 59330, Oct. 8, 2008; 75 FR 23042, Apr. 30, 2010; 76 FR 57450, Sept. 15, 2011; 86 FR 34546, June 29, 2021; 88 FR 4678, Jan. 24, 2023] § 1065.516 Sample system decontamination and preconditioning. This section describes how to manage the impact of sampling system contamination on emission measurements. Use good engineering judgment to determine if you should decontaminate and precondition your sampling system. Contamination occurs when a regulated pollutant accumulates in the sample system in a high enough concentration to cause release during emission tests. Hydrocarbons and PM are generally the only regulated pollutants that contaminate sample systems. Note that although this section focuses on avoiding excessive contamination of sampling systems, you must also use good engineering judgment to avoid loss of sample to a sampling system that is too clean. The goal of decontamination is not to perfectly clean the sampling system, but rather to achieve equilibrium between the sampling system and the exhaust so emission components are neither lost to nor entrained from the sampling system. (a) You may perform contamination checks as follows to determine if decontamination is needed: (1) For dilute exhaust sampling systems, measure hydrocarbon and PM emissions by sampling with the CVS dilution air turned on, without an engine connected to it. (2) For raw analyzers and systems that collect PM samples from raw exhaust, measure hydrocarbon and PM emissions by sampling purified air or nitrogen. (3) When calculating zero emission levels, apply all applicable corrections, including initial THC contamination and diluted (CVS) exhaust background corrections. (4) Sampling systems are considered contaminated if either of the following conditions applies: (i) The hydrocarbon emission level exceeds 2% of the flow-weighted mean concentration expected at the HC standard. (ii) The PM emission level exceeds 5% of the level expected at the standard and exceeds 20 µg on a 47 mm PTFE membrane filter. (b) To precondition or decontaminate sampling systems, use the following recommended procedure or select a different procedure using good engineering judgment: (1) Start the engine and use good engineering judgment to operate it at a condition that generates high exhaust temperatures at the sample probe inlet. (2) Operate any dilution systems at their expected flow rates. Prevent aqueous condensation in the dilution systems. (3) Operate any PM sampling systems at their expected flow rates. (4) Sample PM for at least 10 min using any sample media. You may change sample media at any time during this process and you may discard them without weighing them. (5) You may purge any gaseous sampling systems that do not require decontamination during this procedure. (6) You may conduct calibrations or verifications on any idle equipment or analyzers during this procedure. (c) If your sampling system is still contaminated following the procedures specified in paragraph (b) of this section, you may use more aggressive procedures to decontaminate the sampling system, as long as the decontamination does not cause the sampling system to be cleaner than an equilibrium condition such that artificially low emission measurements may result. [79 FR 23774, Apr. 28, 2014] § 1065.518 Engine preconditioning. (a) This section applies for engines where measured emissions are affected by prior operation, such as with a diesel engine that relies on urea-based selective catalytic reduction. Note that § 1065.520(e) allows you to run practice duty cycles before the emission test; this section recommends how to do this for the purpose of preconditioning the engine. Follow the standard-setting part if it specifies a different engine preconditioning procedure. (b) The intent of engine preconditioning is to manage the representativeness of emissions and emission controls over the duty cycle and to reduce bias. (c) This paragraph (c) specifies the engine preconditioning procedures for different types of duty cycles. You must identify the amount of preconditioning before starting to precondition. You must run the predefined amount of preconditioning. You may measure emissions during preconditioning. You may not abort an emission test sequence based on emissions measured during preconditioning. For confirmatory testing, you may ask us to run more preconditioning cycles than we specify in this paragraph (c); we will agree to this only if you show that additional preconditioning cycles are required to meet the intent of paragraph (b) of this section, for example, due to the effect of DPF regeneration on NH 3 (1) Cold-start transient cycle. (2) Hot-start transient cycle. (3) Hot-running transient cycle. (4) Discrete-mode cycle for steady-state testing. (5) Ramped-modal cycle for steady-state testing. (d) You may conduct calibrations or verifications on any idle equipment or analyzers during engine preconditioning. [79 FR 23774, Apr. 28, 2014] § 1065.520 Pre-test verification procedures and pre-test data collection. (a) For tests in which you measure PM emissions, follow the procedures for PM sample preconditioning and tare weighing according to § 1065.590. (b) Unless the standard-setting part specifies different tolerances, verify at some point before the test that ambient conditions are within the tolerances specified in this paragraph (b). For purposes of this paragraph (b), “before the test” means any time from a point just prior to engine starting (excluding engine restarts) to the point at which emission sampling begins. (1) Ambient temperature of (20 to 30) °C. See § 1065.530(j) for circumstances under which ambient temperatures must remain within this range during the test. (2) Atmospheric pressure of (80.000 to 103.325) kPa and within ±5 kPa of the value recorded at the time of the last engine map. You are not required to verify atmospheric pressure prior to a hot start test interval for testing that also includes a cold start. (3) Dilution air conditions as specified in § 1065.140, except in cases where you preheat your CVS before a cold start test. We recommend verifying dilution air conditions just prior to the start of each test interval. (c) You may test engines at any intake-air humidity, and we may test engines at any intake-air humidity. (d) Verify that auxiliary-work inputs and outputs are configured as they were during engine mapping, as described in § 1065.510(a). (e) You may perform a final calibration of the speed, torque, and proportional-flow control systems, which may include performing practice duty cycles (or portions of duty cycles). This may be done in conjunction with the preconditioning in § 1065.518. (f) If your testing requires a chemical balance, then before the start of emissions testing select the chemical balance method and the gaseous emission measurement equipment required for testing. Select the chemical balance method depending on the fuels used during testing: (1) When using only carbon-containing fuels, use the carbon-based chemical balance procedure in § 1065.655. (2) When using only fuels other than carbon-containing fuels, use the hydrogen-based chemical balance procedure in § 1065.656. (3) When using constant mixtures of carbon-containing fuels and fuels other than carbon- containing fuels, use the following chemical balance methods and gaseous emission measurement equipment: (i) If the hydrogen-to-carbon ratio, a (ii) Otherwise, use the hydrogen-based chemical balance procedure in § 1065.656. (4) When using variable mixtures of carbon-containing fuels and fuels other than carbon-containing fuels, if the mean hydrogen-to-carbon ratio of the fuel mixture, a (g) If your testing requires measuring hydrocarbon emissions, verify the amount of nonmethane hydrocarbon contamination in the exhaust and background HC sampling systems within 8 hours before the start of the first test interval of each duty-cycle sequence for laboratory tests. You may verify the contamination of a background HC sampling system by reading the last bag fill and purge using zero gas. For any NMHC measurement system that involves separately measuring CH 4 4 4 4 4 4 (1) Select the HC analyzer range for measuring the flow-weighted mean concentration expected at the HC standard. (2) Zero the HC analyzer at the analyzer zero or sample port. Note that FID zero and span balance gases may be any combination of purified air or purified nitrogen that meets the specifications of § 1065.750. We recommend FID analyzer zero and span gases that contain approximately the flow-weighted mean concentration of O 2 (3) Span the HC analyzer using span gas introduced at the analyzer span or sample port. Span on a carbon number basis of one (C 1 3 8 (4) Overflow zero gas at the HC probe inlet or into a tee near the probe outlet. (5) Measure the THC concentration in the sampling and background systems as follows: (i) For continuous sampling, record the mean THC concentration as overflow zero gas flows. (ii) For batch sampling, fill the sample medium (e.g., bag) and record its mean THC concentration. (iii) For the background system, record the mean THC concentration of the last fill and purge. (6) Record this value as the initial THC concentration, x THC[THC-FID]init (7) You may correct the measured initial THC concentration for drift as follows: (i) For batch and continuous HC analyzers, after determining the initial THC concentration, flow zero gas to the analyzer zero or sample port. When the analyzer reading is stable, record the mean analyzer value. (ii) Flow span gas to the analyzer span or sample port. When the analyzer reading is stable, record the mean analyzer value. (iii) Use mean analyzer values from paragraphs (g)(2) and (3) and (g)(7)(i) and (ii) of this section to correct the initial THC concentration recorded in paragraph (g)(6) of this section for drift, as described in § 1065.550. (8) If any of the x THC[THC-FID]init (i) 2% of the flow-weighted mean concentration expected at the HC (THC or NMHC) standard. (ii) 2% of the flow-weighted mean concentration of HC (THC or NMHC) measured during testing. (iii) 2 µmol/mol. (9) If corrective action does not resolve the deficiency, you may request to use the contaminated system as an alternate procedure under § 1065.10. [79 FR 23775, Apr. 28, 2014, as amended at 89 FR 29806, Apr. 22, 2024] § 1065.525 Engine starting, restarting, and shutdown. (a) For test intervals that require emission sampling during engine starting, start the engine using one of the following methods: (1) Start the engine as recommended in the owners manual using a production starter motor or air-start system and either an adequately charged battery, a suitable power supply, or a suitable compressed air source. (2) Use the dynamometer to start the engine. To do this, motor the engine within ±25% of its typical in-use cranking speed. Stop cranking within 1 second of starting the engine. (3) In the case of hybrid engines, activate the system such that the engine will start when its control algorithms determine that the engine should provide power instead of or in addition to power from the RESS. Unless we specify otherwise, engine starting throughout this part generally refers to this step of activating the system on hybrid engines, whether or not that causes the engine to start running. (b) If the engine does not start after 15 seconds of cranking, stop cranking and determine why the engine failed to start, unless the owners manual or the service-repair manual describes the longer cranking time as normal. (c) Respond to engine stalling with the following steps: (1) If the engine stalls during warm-up before emission sampling begins, restart the engine and continue warm-up. (2) If the engine stalls during preconditioning before emission sampling begins, restart the engine and restart the preconditioning sequence. (3) Void the entire test if the engine stalls at any time after emission sampling begins, except as described in § 1065.526. If you do not void the entire test, you must void the individual test mode or test interval in which the engine stalls. (d) Shut down the engine according to the manufacturer's specifications. [73 FR 37320, June 30, 2008, as amended at 75 FR 68463, Nov. 8, 2010; 76 FR 57451, Sept. 15, 2011] § 1065.526 Repeating of void modes or test intervals. (a) Test modes and test intervals can be voided because of instrument malfunction, engine stalling, emissions exceeding instrument ranges, and other unexpected deviations from the specified procedures. This section specifies circumstances for which a test mode or test interval can be repeated without repeating the entire test. (b) This section is intended to result in replicate test modes and test intervals that are identical to what would have occurred if the cause of the voiding had not occurred. It does not allow you to repeat test modes or test intervals in any circumstances that would be inconsistent with good engineering judgment. For example, the procedures specified here for repeating a mode or interval may not apply for certain engines that include hybrid energy storage features or emission controls that involve physical or chemical storage of pollutants. This section applies for circumstances in which emission concentrations exceed the analyzer range only if it is due to operator error or analyzer malfunction. It does not apply for circumstances in which the emission concentrations exceed the range because they were higher than expected. (c) If one of the modes of a discrete-mode duty cycle is voided while running the duty cycle as provided in this section, you may void the results for that individual mode and continue the duty cycle as follows: (1) If the engine has stalled or been shut down, restart the engine. (2) Use good engineering judgment to restart the duty cycle using the appropriate steps in § 1065.530(b). (3) Stabilize the engine by operating it at the mode at which the duty cycle was interrupted and continue with the duty cycle as specified in the standard-setting part. (d) If an individual mode of a discrete-mode duty cycle sequence is voided after running the full duty cycle, you may void results for that mode and repeat testing for that mode as follows: (1) Use good engineering judgment to restart the test sequence using the appropriate steps in § 1065.530(b). (2) Stabilize the engine by operating it at that mode. (3) Sample emissions over an appropriate test interval. (4) If you sampled gaseous and PM emissions over separate test intervals for a voided mode, you must void both test intervals and repeat sampling of both gaseous and PM emissions for that mode. (e) If a transient or ramped-modal cycle test interval is voided as provided in this section, you may repeat the test interval as follows: (1) Use good engineering judgment to restart (as applicable) and precondition the engine to the same condition as would apply for normal testing. This may require you to complete the voided test interval. For example, you may generally repeat a hot-start test of a heavy-duty highway engine after completing the voided hot-start test and allowing the engine to soak for 20 minutes. (2) Complete the remainder of the test according to the provisions in this subpart. (f) Keep records from the voided test mode or test interval in the same manner as required for unvoided tests. [79 FR 23776, Apr. 28, 2014] § 1065.530 Emission test sequence. (a) Time the start of testing as follows: (1) Perform one of the following if you precondition the engine as described in § 1065.518: (i) For cold-start duty cycles, shut down the engine. Unless the standard-setting part specifies that you may only perform a natural engine cooldown, you may perform a forced engine cooldown. Use good engineering judgment to set up systems to send cooling air across the engine, to send cool oil through the engine lubrication system, to remove heat from coolant through the engine cooling system, and to remove heat from any exhaust aftertreatment systems. In the case of a forced aftertreatment cooldown, good engineering judgment would indicate that you not start flowing cooling air until the aftertreatment system has cooled below its catalytic activation temperature. For platinum-group metal catalysts, this temperature is about 200 °C. Once the aftertreatment system has naturally cooled below its catalytic activation temperature, good engineering judgment would indicate that you use clean air with a temperature of at least 15 °C, and direct the air through the aftertreatment system in the normal direction of exhaust flow. Do not use any cooling procedure that results in unrepresentative emissions (see § 1065.10(c)(1)). You may start a cold-start duty cycle when the temperatures of an engine's lubricant, coolant, and aftertreatment systems are all between (20 and 30) °C. (ii) For hot-start emission measurements, shut down the engine immediately after completing the last preconditioning cycle. For any repeat cycles, start the hot-start transient emission test within 60 seconds after completing the last preconditioning cycle (this is optional for manufacturer testing). (iii) For testing that involves hot-stabilized emission measurements, such as any steady-state testing with a ramped-modal cycle, start the hot-stabilized emission test within 60 seconds after completing the last preconditioning cycle (the time between cycles is optional for manufacturer testing). If the hot-stabilized cycle begins and ends with different operating conditions, add a linear transition period of 20 seconds between hot-stabilized cycles where you linearly ramp the (denormalized) reference speed and torque values over the transition period. See § 1065.501(c)(2)(i) for discrete-mode cycles. (2) If you do not precondition the engine as described in § 1065.518, perform one of the following: (i) For cold-start duty cycles, prepare the engine according to paragraph (a)(1)(i) of this section. (ii) For hot-start duty cycles, first operate the engine at any speed above peak-torque speed and at (65 to 85)% of maximum mapped power until either the engine coolant, block, lubricating oil, or head absolute temperature is within ±2% of its mean value for at least 2 min or until the engine thermostat controls engine temperature. Shut down the engine. Start the duty cycle within 20 min of engine shutdown. (iii) For testing that involves hot-stabilized emission measurements, bring the engine either to warm idle or the first operating point of the duty cycle. Start the test within 10 min of achieving temperature stability. Determine temperature stability as the point at which the engine thermostat controls engine temperature or as the point at which measured operating temperature has stayed within ±2% of the mean value for at least 2 min based on the following parameters: (A) Engine coolant, block, lubricating oil, or head absolute temperatures for water-cooled engines. (B) Oil sump absolute temperature for air-cooled engines with an oil sump. (C) Cylinder head absolute temperature or exhaust gas temperature for air-cooled engines with no oil sump. (b) Take the following steps before emission sampling begins: (1) For batch sampling, connect clean storage media, such as evacuated bags or tare-weighed filters. (2) Start all measurement instruments according to the instrument manufacturer's instructions and using good engineering judgment. (3) Start dilution systems, sample pumps, cooling fans, and the data-collection system. (4) Pre-heat or pre-cool heat exchangers in the sampling system to within their operating temperature tolerances for a test interval. (5) Allow heated or cooled components such as sample lines, filters, chillers, and pumps to stabilize at their operating temperatures. (6) Verify that there are no significant vacuum-side leaks according to § 1065.345. (7) Adjust the sample flow rates to desired levels, using bypass flow, if desired. (8) Zero or re-zero any electronic integrating devices, before the start of any test interval. (9) Select gas analyzer ranges. You may automatically or manually switch gas analyzer ranges during a test interval only if switching is performed by changing the span over which the digital resolution of the instrument is applied. During a test interval you may not switch the gains of an analyzer's analog operational amplifier(s). (10) Zero and span all continuous analyzers using NIST-traceable gases that meet the specifications of § 1065.750. Span FID analyzers on a carbon number basis of one (1), C 1 3 8 RF PF (11) We recommend that you verify gas analyzer responses after zeroing and spanning by sampling a calibration gas that has a concentration near one-half of the span gas concentration. Based on the results and good engineering judgment, you may decide whether or not to re-zero, re-span, or re-calibrate a gas analyzer before starting a test interval. (12) Drain any accumulated condensate from the intake air system before starting a duty cycle, as described in § 1065.125(e)(1). If engine and aftertreatment preconditioning cycles are run before the duty cycle, treat the preconditioning cycles and any associated soak period as part of the duty cycle for the purpose of opening drains and draining condensate. Note that you must close any intake air condensate drains that are not representative of those normally open during in-use operation. (c) Start and run each test interval as described in this paragraph (c). The procedure varies depending on whether the test interval is part of a discrete-mode cycle, and whether the test interval includes engine starting. Note that the standard-setting part may apply different requirements for running test intervals. For example, 40 CFR part 1033 specifies a different way to perform discrete-mode testing. (1) For steady-state discrete-mode duty cycles, start the duty cycle with the engine warmed-up and running as described in § 1065.501(c)(2)(i). Run each mode in the sequence specified in the standard-setting part. This will require controlling engine speed, engine load, or other operator demand settings as specified in the standard-setting part. Simultaneously start any electronic integrating devices, continuous data recording, and batch sampling. We recommend that you stabilize the engine for at least 5 minutes for each mode. Once sampling begins, sample continuously for at least 1 minute. Note that longer sample times may be needed for accurately measuring very low emission levels. (2) For transient and steady-state ramped-modal duty cycles that do not include engine starting, start the test interval with the engine running as soon as practical after completing engine preconditioning. Simultaneously start any electronic integrating devices, continuous data recording, batch sampling, and execution of the duty cycle. (3) If engine starting is part of the test interval, simultaneously start any electronic integrating devices, continuous data recording, and batch sampling before attempting to start the engine. Initiate the sequence of points in the duty cycle when the engine starts. (4) For batch sampling systems, you may advance or delay the start and end of sampling at the beginning and end of the test interval to improve the accuracy of the batch sample, consistent with good engineering judgment. (d) At the end of each test interval, continue to operate all sampling and dilution systems to allow the sampling system's response time to elapse. Then stop all sampling and recording, including the recording of background samples. Finally, stop any integrating devices and indicate the end of the duty cycle in the recorded data. (e) Shut down the engine if you have completed testing or if it is part of the duty cycle. (f) If testing involves another duty cycle after a soak period with the engine off, start a timer when the engine shuts down, and repeat the steps in paragraphs (b) through (e) of this section as needed. (g) Take the following steps after emission sampling is complete: (1) For any proportional batch sample, such as a bag sample or PM sample, verify that proportional sampling was maintained according to § 1065.545. Void any samples that did not maintain proportional sampling according to § 1065.545. (2) Place any used PM samples into covered or sealed containers and return them to the PM-stabilization environment. Follow the PM sample post-conditioning and total weighing procedures in § 1065.595. (3) As soon as practical after the duty cycle is complete, or during the soak period if practical, perform the following: (i) Zero and span all batch gas analyzers no later than 30 minutes after the duty cycle is complete, or during the soak period if practical. (ii) Analyze any conventional gaseous batch samples no later than 30 minutes after the duty cycle is complete, or during the soak period if practical. (iii) Analyze background samples no later than 60 minutes after the duty cycle is complete. (iv) Analyze non-conventional gaseous batch samples, such as ethanol (NMHCE) as soon as practical using good engineering judgment. (4) After quantifying exhaust gases, verify drift as follows: (i) For batch and continuous gas analyzers, record the mean analyzer value after stabilizing a zero gas to the analyzer. Stabilization may include time to purge the analyzer of any sample gas, plus any additional time to account for analyzer response. (ii) Record the mean analyzer value after stabilizing the span gas to the analyzer. Stabilization may include time to purge the analyzer of any sample gas, plus any additional time to account for analyzer response. (iii) Use these data to validate and correct for drift as described in § 1065.550. (5) If you perform the optional carbon balance error verification, verify carbon balance error as specified in the standard-setting part and § 1065.543. Calculate and report the three carbon balance error quantities for each test interval; carbon mass absolute error for a test interval, ε aC ε aCrate ε rC ε rCcomp ε rCcomp ε aC ε aCrate ε rC (h) Unless the standard-setting part specifies otherwise, determine whether or not the test meets the cycle-validation criteria in § 1065.514. (1) If the criteria void the test, you may retest using the same denormalized duty cycle, or you may re-map the engine, denormalize the reference duty cycle based on the new map and retest the engine using the new denormalized duty cycle. (2) If the criteria void the test for a constant-speed engine only during commands of maximum test torque, you may do the following: (i) Determine the first and last feedback speeds at which maximum test torque was commanded. (ii) If the last speed is greater than or equal to 90% of the first speed, the test is void. You may retest using the same denormalized duty cycle, or you may re-map the engine, denormalize the reference duty cycle based on the new map and retest the engine using the new denormalized duty cycle. (iii) If the last speed is less than 90% of the first speed, reduce maximum test torque by 5%, and proceed as follows: (A) Denormalize the entire duty cycle based on the reduced maximum test torque according to § 1065.512. (B) Retest the engine using the denormalized test cycle that is based on the reduced maximum test torque. (C) If your engine still fails the cycle criteria, reduce the maximum test torque by another 5% of the original maximum test torque. (D) If your engine fails after repeating this procedure four times, such that your engine still fails after you have reduced the maximum test torque by 20% of the original maximum test torque, notify us and we will consider specifying a more appropriate duty cycle for your engine under the provisions of § 1065.10(c). (i) [Reserved] (j) Measure and record ambient temperature, pressure, and humidity, as appropriate. For testing the following engines, you must record ambient temperature continuously to verify that it remains within the pre-test temperature range as specified in § 1065.520(b): (1) Air-cooled engines. (2) Engines equipped with auxiliary emission control devices that sense and respond to ambient temperature. (3) Any other engine for which good engineering judgment indicates this is necessary to remain consistent with § 1065.10(c)(1). [73 FR 37321, June 30, 2008, as amended at 75 FR 23043, Apr. 30, 2010; 76 FR 57451, Sept. 15, 2011; 79 FR 23776, Apr. 28, 2014; 86 FR 34546, June 29, 2021; 87 FR 64865, Oct. 26, 2022; 88 FR 4679, Jan. 24, 2023; 89 FR 29806, Apr. 22, 2024] § 1065.543 Carbon balance error verification. (a) This optional carbon balance error verification compares independently calculated quantities of carbon flowing into and out of an engine system. The engine system includes aftertreatment devices as applicable. Calculating carbon intake considers carbon-carrying streams flowing into the system, including intake air, fuel, and optionally DEF or other fluids. Carbon flow out of the system comes from exhaust emission calculations. Note that this verification is not valid if you calculate exhaust molar flow rate using fuel rate and chemical balance as described in § 1065.655(f)(3) because carbon flows into and out of the system are not independent. Use good engineering judgment to ensure that carbon mass in and carbon mass out data signals align. (b) Perform the carbon balance error verification after emission sampling is complete for a test sequence as described in § 1065.530(g)(5). Testing must include measured values as needed to determine intake air, fuel flow, and carbon-related gaseous exhaust emissions. You may optionally account for the flow of carbon-carrying fluids other than intake air and fuel into the system. Perform carbon balance error verification as follows: (1) Calculate carbon balance error quantities as described in § 1065.643. The three quantities for individual test intervals are carbon mass absolute error, ε aC ε aCrate ε rC ε aC ε aCrate ε rC ε rCcomp (2) You meet the carbon balance error verification for a test sequence if all test intervals pass the test-interval criteria. A test interval passes if at least one of the absolute values of the three carbon balance error quantities for test intervals, ε aC ε aCrate ε rC ε rCcomp (i) Calculate the carbon mass absolute error limit, L ε aC ε aC Where: c P max max max Example: c P max L ε aC L ε aC (ii) Calculate the carbon mass rate absolute error limit, L ε aCrate ε aCrate Where: d P max P max P max Example: d P max L ε aCrate L ε aCrate (iii) The carbon mass relative error limit, L ε rC ε rC ε rCcomp (c) A failed carbon balance error verification might indicate one or more problems requiring corrective action, as follows: Table 1 of § 1065.543—Troubleshooting Guide for Carbon Balance Error Verification Area of concern Problem Recommended corrective action Gas analyzer system Incorrect analyzer calibration Calibrate NDIR and THC analyzers. Incorrect time alignment between flow and concentration data Determine transformation time, t 50 Problems with the sample system Inspect sample system components such as sample lines, filters, chillers, and pumps for leaks, operating temperature, and contamination. Fuel flow measurement Zero shift of fuel flow rate meter Perform an in-situ zero adjustment. Change in fuel flow meter calibration Calibrate the fuel flow meter as described in § 1065.320. Incorrect time alignment of fuel flow data Verify alignment of carbon mass in and carbon mass out data streams. Short sampling periods For test intervals with varying duration, such as discrete-mode steady-state duty cycles, make the test intervals longer to improve accuracy when measuring low fuel flow rates. Fluctuations in the fuel conditioning system Improve stability of the fuel temperature and pressure conditioning system to improve accuracy when measuring low fuel flow rates. Dilute testing using a CVS system Leaks Inspect exhaust system and CVS tunnel, connections, and fasteners. Repair or replace components as needed. A leak in the exhaust transfer tube to the CVS may result in negative values for carbon balance error. Poor mixing Perform the verification related to mixing in § 1065.341(f). Change in CVS calibration Calibrate the CVS flow meter as described in § 1065.340. Flow meter entrance effects Inspect the CVS tunnel to determine whether entrance effects from the piping configuration upstream of the flow meter adversely affect flow measurement. Other problems with the CVS or sampling verification hardware or software Inspect hardware and software for the CVS system and CVS verification system for discrepancies. Raw testing using intake air flow measurement or direct exhaust flow measurement Leaks Inspect intake air and exhaust systems, connections, fasteners. Repair or replace components as needed. Zero shift of intake air flow rate meter Perform an in-situ zero adjustment. Change in intake air flow meter calibration Calibrate the intake air flow meter as described in § 1065.325. Zero shift of exhaust flow rate meter Perform an in-situ zero adjustment. Change in exhaust flow meter calibration Calibrate the exhaust flow meter as described in § 1065.330. Flow meter entrance effects Inspect intake air and exhaust systems to determine whether entrance effects from the piping configuration upstream and downstream of the intake air flow meter or the exhaust flow meter adversely affect flow measurement. Other problems with the intake air flow and exhaust flow measurement hardware or software Look for discrepancies in the hardware and software for measuring intake air flow and exhaust flow. Poor mixing Ensure that all streams are well mixed. Accuracy of fluid properties Inaccurate fluid properties If defaults are used, use measured values. If measured values are used, verify fluid property determination. [86 FR 34547, June 29, 2021; 87 FR 64865, Oct. 26, 2022; 88 FR 4679, Jan. 24, 2023] § 1065.545 Verification of proportional flow control for batch sampling. For any proportional batch sample such as a bag or PM filter, demonstrate that proportional sampling was maintained using one of the following, noting that you may omit up to 5% of the total number of data points as outliers: (a) For any pair of sample and total flow rates, use continuous recorded data or 1 Hz means. Total flow rate means the raw exhaust flow rate for raw exhaust sampling and the dilute exhaust flow rate for CVS sampling. For each test interval, determine the standard error of the estimate, SEE, SEE (b) For any pair of sample and total flow rates, use continuous recorded data or 1 Hz means. Total flow rate means the raw exhaust flow rate for raw exhaust sampling and the dilute exhaust flow rate for CVS sampling. For each test interval, demonstrate that each flow rate is constant within ±2.5% of its respective mean or target flow rate. You may use the following options instead of recording the respective flow rate of each type of meter: (1) Critical-flow venturi option. (2) Positive-displacement pump option. (c) Using good engineering judgment, demonstrate with an engineering analysis that the proportional-flow control system inherently ensures proportional sampling under all circumstances expected during testing. For example, you might use CFVs for both sample flow and total dilute exhaust (CVS) flow and demonstrate that they always have the same inlet pressures and temperatures and that they always operate under critical-flow conditions. [79 FR 23777, Apr. 28, 2014, as amended at 86 FR 34548, June 29, 2021; 88 FR 4679, Jan. 24, 2023] § 1065.546 Verification of minimum dilution ratio for PM batch sampling. Use continuous flows and/or tracer gas concentrations for transient and ramped-modal cycles to verify the minimum dilution ratios for PM batch sampling as specified in § 1065.140(e)(2) over the test interval. You may use mode-average values instead of continuous measurements for discrete mode steady-state duty cycles. Determine the minimum primary and minimum overall dilution ratios using one of the following methods (you may use a different method for each stage of dilution): (a) Determine minimum dilution ratio based on molar flow data. This involves determination of at least two of the following three quantities: raw exhaust flow (or previously diluted flow), dilution air flow, and dilute exhaust flow. You may determine the raw exhaust flow rate based on the measured intake air or fuel flow rate and the raw exhaust chemical balance terms as given in § 1065.655(f). You may determine the raw exhaust flow rate based on the measured intake air and dilute exhaust molar flow rates and the dilute exhaust chemical balance terms as given in § 1065.655(g). You may alternatively estimate the molar raw exhaust flow rate based on intake air, fuel rate measurements, and fuel properties, consistent with good engineering judgment. (b) Determine minimum dilution ratio based on tracer gas ( e.g. 2 (c) Use good engineering judgment to develop your own method of determining dilution ratios. [75 FR 23043, Apr. 30, 2010, as amended at 76 FR 57451, Sept. 15, 2011; 79 FR 23778, Apr. 28, 2014; 81 FR 74169, Oct. 25, 2016] § 1065.550 Gas analyzer range verification and drift verification. (a) Range verification. (1) For batch sampling, re-analyze the sample using the lowest analyzer range that results in a maximum instrument response below 100%. Report the result from the lowest range from which the analyzer operates below 100% of its range. (2) For continuous sampling, repeat the entire test using the next higher analyzer range. If the analyzer again operates above 100% of its range, repeat the test using the next higher range. Continue to repeat the test until the analyzer always operates at less than 100% of its range. (b) Drift verification. 2 2 2 2 3 4 2 (1) Verify drift using one of the following methods: (i) For regulated exhaust constituents determined from the mass of a single component, perform drift verification based on the regulated constituent. For example, when NO X 2 X X (ii) For regulated exhaust constituents determined from the masses of multiple subcomponents, perform the drift verification based on either the regulated constituent or all the mass subcomponents. For example, when NO X 2 X 2 (iii) For regulated exhaust constituents determined from the concentrations of multiple gaseous emission subcomponents prior to performing mass calculations, perform drift verification on the regulated constituent. You may not verify the concentration subcomponents (e.g., THC and CH 4 4 (2) Drift verification requires two sets of emission calculations. For each set of calculations, include all the constituents in the drift verification. Calculate one set using the data before drift correction and calculate the other set after correcting all the data for drift according to § 1065.672. Note that for purposes of drift verification, you must leave unaltered any negative emission results over a given test interval (i.e., do not set them to zero). These unaltered results are used when verifying either test interval results or composite brake-specific emissions over the entire duty cycle for drift. For each constituent to be verified, both sets of calculations must include the following: (i) Calculated mass (or mass rate) emission values over each test interval. (ii) If you are verifying each test interval based on brake-specific values, calculate brake-specific emission values over each test interval. (iii) If you are verifying over the entire duty cycle, calculate composite brake-specific emission values. (3) The duty cycle is verified for drift if you satisfy the following criteria: (i) For each regulated gaseous exhaust constituent, you must satisfy one of the following: (A) For each test interval of the duty cycle, the difference between the uncorrected and the corrected brake-specific emission values of the regulated constituent must be within ±4% of the uncorrected value or the applicable emissions standard, whichever is greater. Alternatively, the difference between the uncorrected and the corrected emission mass (or mass rate) values of the regulated constituent must be within ±4% of the uncorrected value or the composite work (or power) multiplied by the applicable emissions standard, whichever is greater. For purposes of verifying each test interval, you may use either the reference or actual composite work (or power). (B) For each test interval of the duty cycle and for each mass subcomponent of the regulated constituent, the difference between the uncorrected and the corrected brake-specific emission values must be within ±4% of the uncorrected value. Alternatively, the difference between the uncorrected and the corrected emissions mass (or mass rate) values must be within ±4% of the uncorrected value. (C) For the entire duty cycle, the difference between the uncorrected and the corrected composite brake-specific emission values of the regulated constituent must be within ±4% of the uncorrected value or applicable emission standard, whichever is greater. (D) For the entire duty cycle and for each subcomponent of the regulated constituent, the difference between the uncorrected and the corrected composite brake-specific emission values must be within ±4% of the uncorrected value. (ii) Where no emission standard applies for CO 2 2 2 2 3 (A) For each test interval of the duty cycle, the difference between the uncorrected and the corrected brake-specific CO 2 2 2 2 3 2 2 2 2 3 (B) For the entire duty cycle, the difference between the uncorrected and the corrected composite brake-specific CO 2 2 2 2 3 (4) If the test is not verified for drift as described in paragraph (b)(1) of this section, you may consider the test results for the duty cycle to be valid only if, using good engineering judgment, the observed drift does not affect your ability to demonstrate compliance with the applicable emission standards. For example, if the drift-corrected value is less than the standard by at least two times the absolute difference between the uncorrected and corrected values, you may consider the data to be verified for demonstrating compliance with the applicable standard. [79 FR 23778, Apr. 28, 2014, as amended at 89 FR 29806, Apr. 22, 2024] § 1065.590 PM sampling media (e.g., filters) preconditioning and tare weighing. Before an emission test, take the following steps to prepare PM sampling media (e.g., filters) and equipment for PM measurements: (a) Make sure the balance and PM-stabilization environments meet the periodic verifications in § 1065.390. (b) Visually inspect unused sample media (e.g., filters) for defects and discard defective media. (c) To handle PM sampling media (e.g., filters), use electrically grounded tweezers or a grounding strap, as described in § 1065.190. (d) Place unused sample media (e.g., filters) in one or more containers that are open to the PM-stabilization environment. If you are using filters, you may place them in the bottom half of a filter cassette. (e) Stabilize sample media (e.g., filters) in the PM-stabilization environment. Consider an unused sample medium stabilized as long as it has been in the PM-stabilization environment for a minimum of 30 min, during which the PM-stabilization environment has been within the specifications of § 1065.190. (f) Weigh the sample media (e.g., filters) automatically or manually, as follows: (1) For automatic weighing, follow the automation system manufacturer's instructions to prepare samples for weighing. This may include placing the samples in a special container. (2) Use good engineering judgment to determine if substitution weighing is necessary to show that an engine meets the applicable standard. You may follow the substitution weighing procedure in paragraph (j) of this section, or you may develop your own procedure. (g) Correct the measured mass of each sample medium (e.g., filter) for buoyancy as described in § 1065.690. These buoyancy-corrected values are subsequently subtracted from the post-test mass of the corresponding sample media (e.g., filters) and collected PM to determine the mass of PM emitted during the test. (h) You may repeat measurements to determine the mean mass of each sample medium (e.g., filter). Use good engineering judgment to exclude outliers from the calculation of mean mass values. (i) If you use filters as sample media, load unused filters that have been tare-weighed into clean filter cassettes and place the loaded cassettes in a clean, covered or sealed container before removing them from the stabilization environment for transport to the test site for sampling. We recommend that you keep filter cassettes clean by periodically washing or wiping them with a compatible solvent applied using a lint-free cloth. Depending upon your cassette material, ethanol (C 2 5 (j) Substitution weighing involves measurement of a reference weight before and after each weighing of the PM sampling medium ( e.g., 3 (1) Use electrically grounded tweezers or a grounding strap, as described in § 1065.190. (2) Use a static neutralizer as described in § 1065.190 to minimize static electric charge on any object before it is placed on the balance pan. (3) Select and weigh a substitution weight that meets the requirements for calibration weights found in § 1065.790. The substitution weight must also have the same density as the weight you use to span the microbalance, and be similar in mass to an unused sample medium ( e.g., (4) Record the stable balance reading, then remove the substitution weight. (5) Weigh an unused sample medium ( e.g., (6) Reweigh the substitution weight and record the stable balance reading. (7) Calculate the arithmetic mean of the two substitution-weight readings that you recorded immediately before and after weighing the unused sample. Subtract that mean value from the unused sample reading, then add the true mass of the substitution weight as stated on the substitution-weight certificate. Record this result. This is the unused sample's tare weight without correcting for buoyancy. (8) Repeat these substitution-weighing steps for the remainder of your unused sample media. (9) Once weighing is completed, follow the instructions given in paragraphs (g) through (i) of this section. [73 FR 37323, June 30, 2008, as amended at 81 FR 74169, Oct. 25, 2016] § 1065.595 PM sample post-conditioning and total weighing. After testing is complete, return the sample media (e.g., filters) to the weighing and PM-stabilization environments. (a) Make sure the weighing and PM-stabilization environments meet the ambient condition specifications in § 1065.190(e)(1). If those specifications are not met, leave the test sample media (e.g., filters) covered until proper conditions have been met. (b) In the PM-stabilization environment, remove PM samples from sealed containers. If you use filters, you may remove them from their cassettes before or after stabilization. We recommend always removing the top portion of the cassette before stabilization. When you remove a filter from a cassette, separate the top half of the cassette from the bottom half using a cassette separator designed for this purpose. (c) To handle PM samples, use electrically grounded tweezers or a grounding strap, as described in § 1065.190. (d) Visually inspect the sampling media (e.g., filters) and collected particulate. If either the sample media (e.g., filters) or particulate sample appear to have been compromised, or the particulate matter contacts any surface other than the filter, the sample may not be used to determine particulate emissions. In the case of contact with another surface, clean the affected surface before continuing. (e) To stabilize PM samples, place them in one or more containers that are open to the PM-stabilization environment, as described in § 1065.190. If you expect that a sample medium's (e.g., filter's) total surface concentration of PM will be less than 400 µg, assuming a 38 mm diameter filter stain area, expose the filter to a PM-stabilization environment meeting the specifications of § 1065.190 for at least 30 minutes before weighing. If you expect a higher PM concentration or do not know what PM concentration to expect, expose the filter to the stabilization environment for at least 60 minutes before weighing. Note that 400 µg on sample media (e.g., filters) is an approximate net mass of 0.07 g/kW · hr for a hot-start test with compression-ignition engines tested according to 40 CFR part 86, subpart N, or 50 mg/mile for light-duty vehicles tested according to 40 CFR part 86, subpart B. (f) Repeat the procedures in § 1065.590(f) through (i) to determine post-test mass of the sample media (e.g., filters). (g) Subtract each buoyancy-corrected tare mass of the sample medium (e.g., filter) from its respective buoyancy-corrected mass. The result is the net PM mass, m PM m PM [73 FR 37323, June 30, 2008] Subpart G—Calculations and Data Requirements § 1065.601 Overview. (a) This subpart describes how to— (1) Use the signals recorded before, during, and after an emission test to calculate brake-specific emissions of each measured exhaust constituent. (2) Perform calculations for calibrations and performance checks. (3) Determine statistical values. (b) You may use data from multiple systems to calculate test results for a single emission test, consistent with good engineering judgment. You may also make multiple measurements from a single batch sample, such as multiple weighings of a PM filter or multiple readings from a bag sample. Although you may use an average of multiple measurements from a single test, you may not use test results from multiple emission tests to report emissions. (1) We allow weighted means where appropriate. (2) You may discard statistical outliers, but you must report all results. (3) For emission measurements related to durability testing, we may allow you to exclude certain test points other than statistical outliers relative to compliance with emission standards, consistent with good engineering judgment and normal measurement variability; however, you must include these results when calculating the deterioration factor. This would allow you to use durability data from an engine that has an intermediate test result above the standard that cannot be discarded as a statistical outlier, as long as good engineering judgment indicates that the test result does not represent the engine's actual emission level. Note that good engineering judgment would preclude you from excluding endpoints. Also, if normal measurement variability causes emission results below zero, include the negative result in calculating the deterioration factor to avoid an upward bias. These provisions related to durability testing are intended to address very stringent standards where measurement variability is large relative to the emission standard. (c) You may use any of the following calculations instead of the calculations specified in this subpart G: (1) Mass-based emission calculations prescribed by the International Organization for Standardization (ISO), according to ISO 8178, except the following: (i) ISO 8178-4 Section 9.1.6, NO X (ii) [Reserved] (2) Other calculations that you show are equivalent to within ±0.1% of the brake-specific emission results determined using the calculations specified in this subpart G. [70 FR 40516, July 13, 2005, as amended at 73 FR 37324, June 30, 2008; 74 FR 56516, Oct. 30, 2009; 75 FR 23044, Apr. 30, 2010; 79 FR 23778, Apr. 28, 2014; 89 FR 29807, Apr. 22, 2024] § 1065.602 Statistics. (a) Overview. - ref (b) Arithmetic mean. y Example: N y 1 y 2 y N y 3 y (c) Standard deviation. e.g., Example: N y 1 y 2 y N y 3 y σ y (d) Root mean square. rms y Example: N y 1 y 2 y N y 3 rms y (e) Accuracy. y i y ref i y ref i Example: y ref N y 1 y 2 y 3 accuracy (f) t-test. t t t v Example: Y ref Y σ ref σ y N ref N t σ ref σ y N ref N v (2) For a paired t t v i e.g., y ref i y i Example 1: ε N σ ε t v N Example 2: N v v (3) Use Table 1 of this section to compare t t crit t t crit t t Table 1 of § 1065.602—Critical t v a v Confidence 90% 95% 1 6.314 12.706 2 2.920 4.303 3 2.353 3.182 4 2.132 2.776 5 2.015 2.571 6 1.943 2.447 7 1.895 2.365 8 1.860 2.306 9 1.833 2.262 10 1.812 2.228 11 1.796 2.201 12 1.782 2.179 13 1.771 2.160 14 1.761 2.145 15 1.753 2.131 16 1.746 2.120 18 1.734 2.101 20 1.725 2.086 22 1.717 2.074 24 1.711 2.064 26 1.706 2.056 28 1.701 2.048 30 1.697 2.042 35 1.690 2.030 40 1.684 2.021 50 1.676 2.009 70 1.667 1.994 100 1.660 1.984 1000+ 1.645 1.960 a (g) F-test F Example: F (1) For a 90% confidence F F F crit90 N N ref F F crit90 F F (2) For a 95% confidence F F F crit90 N N ref F F crit95 F F (h) Slope. a 1y (1) If the intercept floats, i.e., Example: N y 1 y y ref1 y ref a 1y (2) If the intercept is forced through zero, such as for verifying proportional sampling: Example: N y 1 y ref1 a 1y (i) Intercept 0y Example: y a 1y y ref a 0y a 0y (j) Standard error of the estimate SEE (1) For a floating intercept: Example: N y 1 a 0y a 1y y ref1 SEE y (2) If the intercept is forced through zero, such as for verifying proportional sampling: Example: N y 1 a 1y y ref1 SEE y (k) Coefficient of determination. r y 2 Example: N y 1 a 0y a 1y y ref1 y (l) Flow-weighted mean concentration. (1) To estimate the flow-weighted mean raw exhaust NO X X (i) Based on your engine design, approximate a map of maximum torque versus speed and use it with the applicable normalized duty cycle in the standard-setting part to generate a reference duty cycle as described in § 1065.610. Calculate the total reference work, W ref t dutycycle p ref (ii) Based on your engine design, estimate maximum power, P max nmax P inmax T inmax P frict V disp V N stroke n exhmax (iii) Use your estimated values as described in the following example calculation: Example: e NOX W ref M NOX 6 Δ t dutycycle P ref P frict P max p max V disp 3 f nmax N stroke η V R T max (2) To estimate the flow-weighted mean NMHC concentration in a CVS from a naturally aspirated nonroad spark-ignition engine at an NMHC standard of 0.5 g/(kW·hr), you may do the following: (i) Based on your engine design, approximate a map of maximum torque versus speed and use it with the applicable normalized duty cycle in the standard-setting part to generate a reference duty cycle as described in § 1065.610. Calculate the total reference work, W ref (ii) Multiply your CVS total molar flow rate by the time interval of the duty cycle, Δ t dutycycle n dexh (iii) Use your estimated values as described in the following example calculation: Example: e NMHC W ref M NMHC 6 n dexh Δ t dutycycle X NMHC (m) Median. M (1) For even numbers of data points: (i) Determine the rank of the data point whose value is used to determine the median as follows: Eq. 1065.602-18 Where: i N Example: N y 1 y 2 y 3 y 4 i i (ii) Determine the median as the average of the data point i i Example: Eq. 1065.602-19 (2) For odd numbers of data points, determine the rank of the data point whose value is the median and the corresponding median value as follows: Eq. 1065.602-20 Where: i N Example: N y 1 y 2 y 3 [86 FR 34548, June 29, 2021; 87 FR 64865, Oct. 26, 2022; 89 FR 29807, Apr. 22, 2024] § 1065.610 Duty cycle generation. This section describes how to generate duty cycles that are specific to your engine, based on the normalized duty cycles in the standard-setting part. During an emission test, use a duty cycle that is specific to your engine to command engine speed, torque, and power, as applicable, using an engine dynamometer and an engine operator demand. Paragraphs (a) and (b) of this section describe how to “normalize” your engine's map to determine the maximum test speed or torque for your engine. The rest of this section describes how to use these values to “denormalize” the duty cycles in the standard-setting parts, which are all published on a normalized basis. Thus, the term “normalized” in paragraphs (a) and (b) of this section refers to different values than it does in the rest of the section. (a) Maximum test speed, ƒ ntest ntest (1) Determine a measured value for ƒ ntest (i) Determine maximum power, P max P max (ii) Determine the lowest and highest engine speeds corresponding to 98% of P max, (iii) Determine the engine speed corresponding to maximum power, f nPmax, P max, f nPmax P max (iv) Transform the map into a normalized power-versus-speed map by dividing power terms by P max f nPmax Where: i f nnorm i f nPmax P norm i P max (v) Determine the maximum value for the sum of the squares from the map and multiply that value by 0.98. (vi) Determine the lowest and highest engine speeds corresponding to the value calculated in paragraph (a)(1)(v) of this section, using linear interpolation as appropriate. Calculate f ntest f ntest (vii) The following example illustrates a calculation of f ntest P max ( f n1 P 1 f nnorm1 P norm1 ( f n2 P 2 f nnorm2 P norm2 ( f n3 P 3 f nnorm3 P norm3 ( f n4 P 4 f nnorm4 P norm4 Sum of squares = (1.002 2 2 Sum of squares = (1.004 2 2 Sum of squares = (1.006 2 2 Sum of squares = (1.008 2 2 (2) For engines with a high-speed governor that will be subject to a reference duty cycle that specifies normalized speeds greater than 100%, calculate an alternate maximum test speed, f ntest,alt f ntest,alt f ntest, f ntest f ntest,alt f ntest,alt f ntest, f ntest,alt f ntest,alt Where: f ntest,alt f nhi,idle f nidle % speed max Example: f nhi,idle f nidle f ntest,alt (3) Transform normalized speeds to reference speeds according to paragraph (c) of this section by using the measured maximum test speed determined according to paragraphs (a)(1) and (2) of this section—or use your declared maximum test speed, as allowed in § 1065.510. (b) Maximum test torque, T test T test (1) For constant speed engines mapped using the methods in § 1065.510(d)(5)(i) or (ii), determine a measured value for T test (i) Determine maximum power, P max, P max. (ii) Determine the lowest and highest engine speeds corresponding to 98% of P max, (iii) Determine the engine speed corresponding to maximum power, f nPmax, P max, f nPmax P max (iv) Transform the map into a normalized power-versus-speed map by dividing power terms by P max f nPmax. (v) Determine the maximum value for the sum of the squares from the map and multiply that value by 0.98. (vi) Determine the lowest and highest engine speeds corresponding to the value calculated in paragraph (a)(1)(v) of this section, using linear interpolation as appropriate. Calculate f ntest f ntest (vii) The measured T test f ntest (2) For constant speed engines using the two-point mapping method in § 1065.510(d)(5)(iii), you may follow paragraph (a)(1) of this section to determine the measured T test T test (3) Transform normalized torques to reference torques according to paragraph (d) of this section by using the measured maximum test torque determined according to paragraph (b)(1) or (2) of this section—or use your declared maximum test torque, as allowed in § 1065.510. (c) Generating reference speed values from normalized duty cycle speeds. (1) % speed. Example: % speed f ntest f nidle f nref f nref (2) A, B, C, and D speeds. n lo. n lo n hi. n hi n hi n lo Example: n lo n hi ƒ nrefA ƒ nrefB ƒ nrefC ƒ nrefD ƒ nrefA ƒ nrefB ƒ nrefC ƒ nrefD (3) Intermediate speed. T max f nTmax T max T max (i) f nTmax (ii) 60% of maximum test speed if f nTmax (iii) 75% of maximum test speed if f nTmax (d) Generating reference torques from normalized duty-cycle torques. (1) Reference torque for variable-speed engines. i.e. i.e. i.e. (2) Reference torque for constant-speed engines. (3) Required deviations. i.e., i.e., (i) Determine the warm-idle-in-drive speed and torque values with the transmission in drive from the data collected during the engine mapping procedure in § 1065.510. The warm-idle-in-drive torque is the sum of CITT and the torques representing loads from vehicle accessories. For example, the sum of the required declared CITT in § 1065.510(f)(4), any optional declared torque in § 1065.510(f)(5)(iii), and the torque on the primary output shaft from any optional declared power in § 1065.510(f)(6). (ii) Determine the warm-idle-in-neutral speed and torque values with the transmission in neutral from the data collected during the engine mapping procedure in § 1065.510. The warm-idle-in-neutral torque is the sum of any optional declared torque in § 1065.510(f)(5)(iii) and the torque on the primary output shaft from any optional declared power in § 1065.510(f)(6) ( i.e., (iii) Zero-percent speed for denormalization of non-idle points is the warm-idle-in-drive speed. (iv) For motoring points, make no changes. (v) If the cycle begins with an idle segment ( i.e., i.e., (vi) For all other idle segments, set the reference speed and torque values to the warm-idle-in-drive values. This is to represent the transmission operating in drive. (vii) If the engine is intended primarily for automatic transmissions with a Neutral-When-Stationary feature that automatically shifts the transmission to neutral after the vehicle is stopped for a designated time and automatically shifts back to drive when the operator increases demand ( i.e., (viii) For all nonidle nonmotoring points with normalized speed at or below zero percent and reference torque from zero to the warm-idle-in-drive torque value, set the reference torque to the warm-idle-in-drive torque value. This is to represent the transmission operating in drive. (ix) For consecutive nonidle nonmotoring points that immediately follow and precede idle segments, with reference torque values from zero to the warm-idle-in-drive torque value, change their reference torques to the warm-idle-in-drive torque value. This is to represent the transmission operating in drive. (x) For consecutive nonidle nonmotoring points that immediately follow and precede any point(s) that were modified in paragraph (d)(3)(viii) of this section, with reference torque values from zero to the warm-idle-in-drive torque value, change their reference torques to the warm-idle-in-drive torque value. This is to provide smooth torque transition around these points. (4) Permissible deviations for any engine. (e) Generating reference power values from normalized duty cycle powers. (1) First transform normalized speed values into reference speed values. For a given speed point, multiply the corresponding % power by the mapped power at maximum test speed, f ntest P ref (2) Permissible deviations for any engine. If your engine does not operate below a certain power under normal in-use conditions, you may use a declared minimum power as the reference value instead of any value denormalized to be less than the declared value. For example, if your engine is directly connected to a propeller, it may have a minimum power called idle power. In this case, you may use this declared minimum power as a reference power value instead of any reference power value generated per paragraph (e)(1) of this section that is from zero to this declared minimum power. [73 FR 37324, June 30, 2008, as amended at 73 FR 59330, Oct. 8, 2008; 75 FR 23045, Apr. 30, 2010; 76 FR 57453, Sept. 15, 2011; 78 FR 36398, June 17, 2013; 79 FR 23783, Apr. 28, 2014; 80 FR 9118, Feb. 19, 2015; 81 FR 74170, Oct. 25, 2016; 86 FR 34555, June 29, 2021; 88 FR 4679, Jan. 24, 2023; 89 FR 29807, Apr. 22, 2024] § 1065.630 Local acceleration of gravity. (a) The acceleration of Earth's gravity, a g a g https://geodesy.noaa.gov/cgi-bin/grav_pdx.prl. (b) If the website specified in paragraph (a) of this section is unavailable, or the test location is outside of the continental United States, you may calculate a g Where: u Example: u a g −3 2 −5 4 −7 6 −10 8 a g 2 [79 FR 23784, Apr. 28, 2014, as amended at 88 FR 4680, Jan. 24, 2023] § 1065.640 Flow meter calibration calculations. This section describes the calculations for calibrating various flow meters. After you calibrate a flow meter using these calculations, use the calculations described in § 1065.642 to calculate flow during an emission test. Paragraph (a) of this section first describes how to convert reference flow meter outputs for use in the calibration equations, which are presented on a molar basis. The remaining paragraphs describe the calibration calculations that are specific to certain types of flow meters. (a) Reference meter conversions. n ref V stdref V actref m ref Where: n ref V stdref V actref m ref p std p act T std T act R M mix Example 1: V stdref 3/min 3/s p std 2 T std R 2 2 n ref Example 2: m ref M mix n ref (b) PDP calibration calculations. (1) Calculate PDP volume pumped per revolution, V rev, Where: n ref R T in P in f nPDP Example: n ref R 2 2 T in P in 2 f nPDP V rev 3 (2) Calculate a PDP slip correction factor, K s Where: f nPDP P out P in Example: f nPDP P out P in K s (3) Perform a least-squares regression of V rev K s a 1 a 0 (4) Repeat the procedure in paragraphs (b)(1) through (3) of this section for every speed that you run your PDP. (5) The following table illustrates a range of typical values for different PDP speeds: Table 1 of § 1065.640—Example of PDP Calibration Data f nPDP a 1 3 a 0 3 12.6 0.841 0.056 16.5 0.831 −0.013 20.9 0.809 0.028 23.4 0.788 −0.061 (6) For each speed at which you operate the PDP, use the appropriate regression equation from this paragraph (b) to calculate flow rate during emission testing as described in § 1065.642. (c) Venturi governing equations and permissible assumptions. r i.e., r SSV r CFV Z C f g C p C v. γ (1) Calculate molar flow rate, n Where: C d C f A t p in Z M mix R T in (2) Using the data collected in § 1065.340, calculate C d Where: n ref (3) Determine C f (i) For CFV flow meters only, determine C fCFV β γ Table 2 of § 1065.640- C fCFV C fCFV b g exh g dexh air = 0.000 0.6822 0.6846 0.400 0.6857 0.6881 0.500 0.6910 0.6934 0.550 0.6953 0.6977 0.600 0.7011 0.7036 0.625 0.7047 0.7072 0.650 0.7089 0.7114 0.675 0.7137 0.7163 0.700 0.7193 0.7219 0.720 0.7245 0.7271 0.740 0.7303 0.7329 0.760 0.7368 0.7395 0.770 0.7404 0.7431 0.780 0.7442 0.7470 0.790 0.7483 0.7511 0.800 0.7527 0.7555 0.810 0.7573 0.7602 0.820 0.7624 0.7652 0.830 0.7677 0.7707 0.840 0.7735 0.7765 0.850 0.7798 0.7828 (ii) For any CFV or SSV flow meter, you may use the following equation to calculate C f Where: g C p C v. r b (4) Calculate r (i) For SSV systems only, calculate r SSV Where: Δp SSV (ii) For CFV systems only, calculate r CFV (5) You may apply any of the following simplifying assumptions or develop other values as appropriate for your test configuration, consistent with good engineering judgment: (i) For raw exhaust, diluted exhaust, and dilution air, you may assume that the gas mixture behaves as an ideal gas: Z (ii) For raw exhaust, you may assume g (iii) For diluted exhaust and dilution air, you may assume g (iv) For diluted exhaust and dilution air, you may assume the molar mass of the mixture, M mix, Where: M air x H2O 2 M H2O Example: M air x H2O M H2O M mix M mix (v) For diluted exhaust and dilution air, you may assume a constant molar mass of the mixture, M mix, You may assume this, using good engineering judgment, if you sufficiently control the amount of water in calibration air and in dilution air or if you remove sufficient water from both calibration air and dilution air. The following table gives examples of permissible ranges of dilution air dewpoint versus calibration air dewpoint: Table 3 of § 1065.640—Examples of Dilution Air and Calibration Air Dewpoints at Which You May Assume a Constant M mix If calibration T dew assume the following constant M mix for the following ranges of T dew a dry 28.96559 dry to 18 0 28.89263 dry to 21 5 28.86148 dry to 22 10 28.81911 dry to 24 15 28.76224 dry to 26 20 28.68685 -8 to 28 25 28.58806 12 to 31 30 28.46005 23 to 34 a (6) The following example illustrates the use of the governing equations to calculate C d C d C f b g Example: n ref Z M mix R 2 2 T in A t 2 p in 2 g b Δp C f C d (d) SSV calibration. (1) Calculate the Reynolds number, Re # n ref d t Re # Re # Where, using the Sutherland three-coefficient viscosity model as captured in Table 4 of this section: Where: µ 0 T 0 S Table 4 of § 1065.640—Sutherland Three-Coefficient Viscosity Model Parameters Gas a µ 0 T 0 S Temperature range within ±2% error b Pressure limit b (kg/(m·s)) (K) (K) (K) (kPa) Air 1.716·10 −5 273 111 170 to 1900 ≤1800 CO 2 1.370·10 −5 273 222 190 to 1700 ≤3600 H 2 1.12·10 −5 350 1064 360 to 1500 ≤10000 O 2 1.919·10 −5 273 139 190 to 2000 ≤2500 N 2 1.663·10 −5 273 107 100 to 1500 ≤1600 a b Example: µ0 = 1.716·10 −5 T S µ = 1.838·10 -5 M mix n ref d t T in Re # 5 (2) Create an equation for C d Re # C d Re # (3) Perform a least-squares regression analysis to determine the best-fit coefficients for the equation and calculate SEE d y y ref SEE (4) If the equation meets the criterion of SEE C dmax, Re # (5) If the equation does not meet the specified statistical criterion, you may use good engineering judgment to omit calibration data points; however you must use at least seven calibration data points to demonstrate that you meet the criterion. For example, this may involve narrowing the range of flow rates for a better curve fit. (6) Take corrective action if the equation does not meet the specified statistical criterion even after omitting calibration data points. For example, select another mathematical expression for the C d Re # (7) Once you have an equation that meets the specified statistical criterion, you may use the equation only for the corresponding range of Re # (e) CFV calibration. C d A t d t d t D C d (1) Use the data collected at each calibration set point to calculate an individual C d (2) Calculate the mean and standard deviation of all the C d (3) If the standard deviation of all the C d C d, C d r, Where: Δ p CFV (4) If the standard deviation of all the C d C d C d r (5) If the number of remaining data points is less than seven, take corrective action by checking your calibration data or repeating the calibration process. If you repeat the calibration process, we recommend checking for leaks, applying tighter tolerances to measurements and allowing more time for flows to stabilize. (6) If the number of remaining C d C d (7) If the standard deviation of the remaining C d C d C d r C d (8) If the standard deviation of the remaining C d C d [79 FR 23785, Apr. 28, 2014, as amended at 81 FR 74172, Oct. 25, 2016; 86 FR 34556, June 29, 2021] § 1065.642 PDP, SSV, and CFV molar flow rate calculations. This section describes the equations for calculating molar flow rates from various flow meters. After you calibrate a flow meter according to § 1065.640, use the calculations described in this section to calculate flow during an emission test. (a) PDP molar flow rate. a 1, a 0, Where: f nPDP V rev p in R T in (2) Calculate V rev p out Example: a 1 3 f nPDP P out P in 2 a 0 3 R 2 2 T in n (b) SSV molar flow rate. n Where: C d C d Re # C f A t p in Z M mix R T in Example: A t 2 p in 2 Z M mix R 2 2 T in Re # 5 γ = 1.399 β = 0.8 Δp = 2.312 kPa Using Eq. 1065.640-7: r ssv Using Eq. 1065.640-6: C f Using Eq. 1065.640-5: C d n (c) CFV molar flow rate. C d K v n n A t d t d t D (1) To calculate n d n Where: C f Example: C d C f A t 2 p in 2 Z M mix R 2 2 T in n (2) To calculate the molar flow rate through one venturi or a combination of venturis, you may use its respective mean, K v n M mix-cal M mix n Where: V stdref T in-cal P in-cal M mix-cal M mix Example: V stdref 3 T in-cal P in-cal 2 p in 2 p std 2 M mix-cal M mix T in T std R 2 2 n [81 FR 74177, Oct. 25, 2016, as amended at 86 FR 34557, June 29, 2021] § 1065.643 Carbon balance error verification calculations. This section describes how to calculate quantities used in the carbon balance error verification described in § 1065.543. Paragraphs (a) through (c) of this section describe how to calculate the mass of carbon for a test interval from carbon-carrying fluid streams, intake air into the system, and exhaust emissions, respectively. Paragraph (d) of this section describes how to use these carbon masses to calculate four different quantities for evaluating carbon balance error. Use rectangular or trapezoidal integration methods to calculate masses and amounts over a test interval from continuously measured or calculated mass and molar flow rates. (a) Fuel and other fluids. m fluidj Where: j N w C m fluid Example: N w Cfuel w CDEF m fuel m DEF m Cfluid (b) Intake air. m Cair m Cair 2 x CO2int x CO2intdry (1) Calculate m Cair Where: M C n int x CO2int 2 Example: M C n int x CO2int m Cair (2) Calculate m Cair Where: M C n exh x H2Oexh 2 x CO2int 2 x dil/exhdry x CO2dil x CO2int x H2Odil x H2Oint x int/exhdry Example: M C n exh x H2Oexh x CO2int x dil/exhdry x int/exhdry m Cair (3) Calculate m Cair Where: M C n exh x CO2int 2 Example: M C n exh x CO2int m Cair (4) Calculate m Cair Where: M C n dexh n dil x CO2int 2 Example: M C n dexh n dil x CO2int m Cair (5) Determined m Cair (6) If you measure diluted exhaust, determine m Cair (c) Exhaust emissions. m Cexh Where: M C m CO2 2 M CO2 m CO M CO m THC M THC 1 Example: M C m CO2 M CO2 m CO M CO m THC M THC (d) Carbon balance error quantities. (1) Calculate carbon mass absolute error, ε aC, Where: m Cexh m Cfluid m Cair Example: m Cexh m Cfluid m Cair ε aC ε aC (2) Calculate carbon mass rate absolute error, ε aCrate, Where: t Example: ε aC t ε aCrate (3) Calculate carbon mass relative error, ε rC, Example: ε aC m Cfluid m Cair ε rC (4) Calculate composite carbon mass relative error, ε rCcomp, (i) Calculate ε rCcomp Where: i N WF m Cexh m Cfluid m Cair t t (ii) The following example illustrates calculation of ε rCcomp, N WF 1 1/7 WF 2 6/7 m Cexh1 m Cexh2 m Cfluid1 m Cfluid2 m Cair1 m Cair2 ε rCcomp (iii) The following example illustrates calculation of ε rCcomp N WF 1 WF 2 m Cexh1 m Cexh2 m Cfluid1 m Cfluid2 m Cair1 m Cair2 t 1 t 2 ε rCcomp [86 FR 34557, June 29, 2021, as amended at 87 FR 64865, Oct. 26, 2022; 88 FR 4680, Jan. 24, 2023] § 1065.644 Vacuum-decay leak rate. This section describes how to calculate the leak rate of a vacuum-decay leak verification, which is described in § 1065.345(e). Use the following equation to calculate the leak rate, , and compare it to the criterion specified in § 1065.345(e): Eq. 1065.644-1 Where: V vac R p 2 2. T 2 2. p 1 1. T 1 1. t 2 t 1 Example: V vac 3 R 2 2 p 2 2 T 2 p 1 2 T 1 t 2 t 1 [89 FR 29808, Apr. 22, 2024] § 1065.645 Amount of water in an ideal gas. This section describes how to determine the amount of water in an ideal gas, which you need for various performance verifications and emission calculations. Use the equation for the vapor pressure of water in paragraph (a) of this section or another appropriate equation and, depending on whether you measure dewpoint or relative humidity, perform one of the calculations in paragraph (b) or (c) of this section. Paragraph (d) of this section provides an equation for determining dewpoint from relative humidity and dry bulb temperature measurements. The equations for the vapor pressure of water as presented in this section are derived from equations in “Saturation Pressure of Water on the New Kelvin Temperature Scale” (Goff, J.A., Transactions American Society of Heating and Air-Conditioning Engineers, Vol. 63, No. 1607, pages 347-354). Note that the equations were originally published to derive vapor pressure in units of atmospheres and have been modified to derive results in units of kPa by converting the last term in each equation. (a) Vapor pressure of water. T sat (1) For humidity measurements made at ambient temperatures from (0 to 100) °C, or for humidity measurements made over super-cooled water at ambient temperatures from (−50 to 0) °C, use the following equation: (2) For humidity measurements over ice at ambient temperatures from (-100 to 0) °C, use the following equation: (b) Dewpoint. x H20 Where: x H20 p H20 T sat T dew p abs Example: : p abs T sat T dew Using Eq. 1065.645-1, p H20 x H2O x H2O (c) Relative humidity. RH, x H2O Where: x H2O RH p H2O T sat T amb p abs Example: RH p abs T sat T amb Using Eq. 1065.645-1, p H2O x H2O x H2O (d) Dewpoint determination from relative humidity and dry bulb temperature. RH. p H20sat T sat T amb p H20scaled p H20sat RH. T dew p H20 Where: ln( p H2O p H2Oscaled, T sat T amb Example: RH T sat = T amb Using Eq. 1065.645-1, p H2Osat p H2Oscaled [73 FR 37327, June 30, 2008, as amended at 73 FR 59331, Oct. 8, 2008; 75 FR 23048, Apr. 30, 2010; 76 FR 57456, Sept. 15, 2011;79 FR 23796, Apr. 28, 2014; 81 FR 74179, Oct. 25, 2016] § 1065.650 Emission calculations. (a) General. i.e., i (b) Brake-specific emissions over a test interval. (1) For any testing, you may calculate the total mass of emissions, as described in paragraph (c) of this section, and divide it by the total work generated over the test interval, as described in paragraph (d) of this section, using the following equation: Example: m NOx W e NOx e NOx (2) For discrete-mode steady-state testing, you may calculate the brake-specific emissions over a test interval using the ratio of emission mass rate to power, as described in paragraph (e) of this section, using the following equation: (3) For field testing, you may calculate the ratio of total mass to total work, where these individual values are determined as described in paragraph (f) of this section. You may also use this approach for laboratory testing, consistent with good engineering judgment. Good engineering judgment dictates that this method not be used if there are any work flow paths described in § 1065.210 that cross the system boundary, other than the primary output shaft (crankshaft). This is a special case in which you use a signal linearly proportional to raw exhaust molar flow rate to determine a value proportional to total emissions. You then use the same linearly proportional signal to determine total work using a chemical balance of fuel, DEF, intake air, and exhaust as described in § 1065.655, plus information about your engine's brake-specific fuel consumption. Under this method, flow meters need not meet accuracy specifications, but they must meet the applicable linearity and repeatability specifications in subpart D or J of this part. The result is a brake-specific emission value calculated as follows: Example: m W e CO e CO (c) Total mass of emissions over a test interval. (1) Concentration corrections. (i) Use good engineering judgment to time-align flow and concentration data to match transformation time, t 50 (ii) Correct all gaseous emission analyzer concentration readings, including continuous readings, sample bag readings, and dilution air background readings, for drift as described in § 1065.672. Note that you must omit this step where brake-specific emissions are calculated without the drift correction for performing the drift validation according to § 1065.550(b). When applying the initial THC and CH 4 (iii) Correct all THC and CH 4 (iv) Correct all concentrations measured on a “dry” basis to a “wet” basis, including dilution air background concentrations, as described in § 1065.659. (v) Calculate all NMHC and CH 4 (vi) For emission testing with an oxygenated fuel, calculate any HC concentrations, including dilution air background concentrations, as described in § 1065.665. See subpart I of this part for testing with oxygenated fuels. (vii) Correct all the NO X (2) Continuous sampling. (i) Varying flow rate. M. m. m Where: Example: M NMHC N x NMHC1 − 6 x NMHC2 − 6 n exh1 n exh2 ƒ record Using Eq. 1065.650-5, Δ t m NMHC − 6 − 6 x NMHC1200 n exh m NMHC (ii) Constant flow rate. (3) Batch sampling. (i) Varying flow rate. M. m. m PM. m (A) Calculate m x Example: M NO X N x − 6 n dexh1 n dexh2 ƒ record Using Eq. 1065.650-5: Δ t m NO X − 6 n exh9000 m NO X (B) Calculate m M (ii) Proportional or constant flow rate. M. m. m PM. m (A) Calculate m x (B) Calculate m for sampling PM or any other analysis of a batch sample that yields a mass per mole of exhaust, M (C) The following example illustrates a calculation of m PM M PM − 6 n dexh Δ t m PM − 6 m PM (4) Additional provisions for diluted exhaust sampling; continuous or batch. (i) For sampling with a constant dilution ratio, DR, e.g., m Example: m PMdil DR m PM m PM (ii) For continuous or batch sampling, you may measure background emissions in the dilution air. You may then subtract the measured background emissions, as described in § 1065.667. (5) Mass of NMHC. (6) Mass of NMNEHC. (i) If the test fuel has less than 0.010 mol/mol of ethane and you omit the NMNEHC calculations as described in § 1065.660(c)(1), take the corrected mass of NMNEHC to be 0.95 times the corrected mass of NMHC. (ii) If the test fuel has at least 0.010 mol/mol of ethane and you omit the NMNEHC calculations as described in § 1065.660(c)(1), take the corrected mass of NMNEHC to be 1.0 times the corrected mass of NMHC. (d) Total work over a test interval. (1) Time align the recorded feedback speed and torque values by the amount used in § 1065.514(c). (2) Calculate shaft power at each point during the test interval by multiplying all the recorded feedback engine speeds by their respective feedback torques. (3) Adjust (reduce) the shaft power values for accessories according to § 1065.110. (4) Set all power values during any cranking or starting period to zero. See § 1065.525 for more information about engine cranking. (5) Set all negative power values to zero, unless the engine was connected to one or more energy storage devices. If the engine was tested with an energy storage device, leave negative power values unaltered. (6) Set all power values to zero during idle periods with a corresponding reference torque of 0 N · m. (7) Integrate the resulting values for power over the test interval. Calculate total work as follows: Where: W P i i. Example: N ƒ n1 ƒ n2 T 1 T 2 C rev π C t1 C p ƒ record C t2 P 1 P 2 Using Eq. 1065.650-5: Δ t W (8) You may use a trapezoidal integration method instead of the rectangular integration described in this paragraph (d). To do this, you must integrate the fraction of work between points where the torque is positive. You may assume that speed and torque are linear between data points. You may not set negative values to zero before running the integration. (e) Steady-state mass rate divided by power. m P (1) To calculate, m x n M. m n m PM m (2) To calculate an engine's mean steady-state total power, P P P f n T (3) Divide emission mass rate by power to calculate a brake-specific emission result as described in paragraph (b)(2) of this section. (4) The following example shows how to calculate mass of emissions using mean mass rate and mean power: M CO x CO n f n T m m P P P e CO e CO (f) Ratio of total mass of emissions to total work. (1) Total mass. n n, n n (2) Total work. e fuel, w C. w C n Where: (3) Brake-specific emissions. (4) Example: The following example shows how to calculate mass of emissions using proportional values: N ƒ record e fuel w fuel M C n 1 x Ccombdry1 x H2Oexh1 Using Eq. 1065.650-5, Δ t W (g) Brake-specific emissions over a duty cycle with multiple test intervals. X (1) Use the following equation to calculate composite brake-specific emissions for duty cycles with multiple test intervals all with prescribed durations, such as cold-start and hot-start transient cycles: Where: i N WF m W Example: N WF 1 WF 2 m 1 m 2 W 1 W 2 e NOxcomp (2) Calculate composite brake-specific emissions for duty cycles with multiple test intervals that allow use of varying duration, such as discrete-mode steady-state duty cycles, as follows: (i) Use the following equation if you calculate brake-specific emissions over test intervals based on total mass and total work as described in paragraph (b)(1) of this section: Where: i N WF m W t Example: N WF 1 WF 2 m 1 m 2 t 1 t 2 W 1 W 2 e NOxcomp (ii) Use the following equation if you calculate brake-specific emissions over test intervals based on the ratio of mass rate to power as described in paragraph (b)(2) of this section: Where: i N WF m p Example: N WF 1 WF 2 m 1 m 2 P 1 P 2 e NOxcomp (h) Rounding. See [73 FR 37328, June 30, 2008, as amended at 73 FR 59332, Oct. 8, 2008; 75 FR 23048, Apr. 30, 2010; 76 FR 57457, Sept. 15, 2011;79 FR 23799, Apr. 28, 2014; 80 FR 9118, Feb. 19, 2015; 81 FR 74180, Oct. 25, 2016; 86 FR 34560, June 29, 2021; 87 FR 64866, Oct. 26, 2022; 88 FR 4681, Jan. 24, 2023; 89 FR 29808, Apr. 22, 2024] § 1065.655 Carbon-based chemical balances of fuel, DEF, intake air, and exhaust. (a) General. (b) Procedures that require chemical balances. (1) A value proportional to total work, W (2) Raw exhaust molar flow rate either from measured intake air molar flow rate or from fuel mass flow rate as described in paragraph (f) of this section. (3) Raw exhaust molar flow rate from measured intake air molar flow rate and dilute exhaust molar flow rate, as described in paragraph (g) of this section. (4) The amount of water in a raw or diluted exhaust flow, x H2Oexh, x H2Oexh. (5) The calculated total dilution air flow when you do not measure dilution air flow to correct for background emissions as described in § 1065.667(c) and (d). (c) Chemical balance procedure. x H2Oexh, x dil/exh, 1 x Ccombdry. x, x H2Oexh, x dry x H2Oexhdry. α, β, γ, δ; α, β, γ, δ (1) Convert your measured concentrations such as, x CO2meas x NOmeas x H2Oint x H2OxCO2meas x H2OxNOmeas x H2Oint x H2Oexh X 2 X 2 X X x NOx 2 2 x NOx 2 X 2 X 2 X (2) Enter the equations in paragraph (c)(4) of this section into a computer program to iteratively solve for x H2Oexh x Ccombdry x dil/exh x H2Oexh x C combdry x dil/exh x Ccombdry 2 x dil/exh (3) Use the following symbols and subscripts in the equations for performing the chemical balance calculations in this paragraph (c): Table 1 of § 1065.655—Symbols and Subscripts for Chemical Balance Equations x dil/exh Amount of dilution gas or excess air per mole of exhaust X dil/exh amount of dilution gas or excess air per mole of exhaust. x Ccombdry amount of carbon from fuel and any injected fluids in the exhaust per mole of dry exhaust x H2dry amount of H 2 K H2Ogas water-gas reaction equilibrium coefficient; you may use 3.5 or calculate your own value using good engineering judgment x H2Oexhdry amount of H 2 x prod/intdry amount of dry stoichiometric products per dry mole of intake air x dil/exhdry amount of dilution gas and/or excess air per mole of dry exhaust x int/exhdry amount of intake air required to produce actual combustion products per mole of dry (raw or diluted) exhaust x raw/exhdry amount of undiluted exhaust, without excess air, per mole of dry (raw or diluted) exhaust x O2int amount of intake air O 2 x CO2intdry amount of intake air CO 2 x CO2intdry x H2Ointdry amount of intake air H 2 x CO2int amount of intake air CO 2 x CO2dil amount of dilution gas CO2 per mole of dilution gas x CO2dildry amount of dilution gas CO 2 x CO2dildry x H2Odildry amount of dilution gas H 2 x H2Odil amount of dilution gas H 2 x [emission]meas amount of measured emission in the sample at the respective gas analyzer x [emission]dry amount of emission per dry mole of dry sample x H2O[emission]meas amount of H 2 x H2Oint amount of H 2 α atomic hydrogen-to-carbon ratio of the fuel (or mixture of test fuels) and any injected fluids β atomic oxygen-to-carbon ratio of the fuel (or mixture of test fuels) and any injected fluids γ atomic sulfur-to-carbon ratio of the fuel (or mixture of test fuels) and any injected fluids δ atomic nitrogen-to-carbon ratio of the fuel (or mixture of test fuels) and any injected fluids (4) Use the following equations to iteratively solve for x dil/exh x H2Oexh x Ccombdry (5) The following example is a solution for x dil/exh,x x H2Oexh x Ccombdry a b g d (d) Carbon mass fraction of fuel. w C w C Where: w C M C a M H b M O g M S d M N Example: a b g d M C M H M O M S M N w C (e) Fuel and diesel exhaust fluid composition. (1) For liquid fuels, use the default values for α, β, γ, δ α, β, γ, δ (i) Determine the carbon and hydrogen mass fractions according to ASTM D5291 (incorporated by reference, see § 1065.1010). When using ASTM D5291 to determine carbon and hydrogen mass fractions of gasoline (with or without blended ethanol), use good engineering judgment to adapt the method as appropriate. This may include consulting with the instrument manufacturer on how to test high-volatility fuels. Allow the weight of volatile fuel samples to stabilize for 20 minutes before starting the analysis; if the weight still drifts after 20 minutes, prepare a new sample). Retest the sample if the carbon, hydrogen, oxygen, sulfur, and nitrogen mass fractions do not add up to a total mass of 100 ±0.5%; you may assume oxygen has a zero mass contribution for this specification for diesel fuel and neat (E0) gasoline. You may also assume that sulfur and nitrogen have a zero mass contribution for this specification for all fuels except residual fuel blends. (ii) Determine oxygen mass fraction of gasoline (with or without blended ethanol) according to ASTM D5599 (incorporated by reference, see § 1065.1010). For all other liquid fuels, determine the oxygen mass fraction using good engineering judgment. (iii) Determine the nitrogen mass fraction according to ASTM D4629 or ASTM D5762 (incorporated by reference, see § 1065.1010) for all liquid fuels. Select the correct method based on the expected nitrogen content. (iv) Determine the sulfur mass fraction according to subpart H of this part. (2) For gaseous fuels and diesel exhaust fluid, use the default values for α, β, γ, and δ in Table 2 of this section, or use good engineering judgment to determine those values based on measurement. (3) For nonconstant fuel mixtures, you must account for the varying proportions of the different fuels. This paragraph (e)(3) generally applies for dual-fuel and flexible-fuel engines, but it also applies if diesel exhaust fluid is injected in a way that is not strictly proportional to fuel flow. Account for these varying concentrations either with a batch measurement that provides averaged values to represent the test interval, or by analyzing data from continuous mass rate measurements. Application of average values from a batch measurement generally applies to situations where one fluid is a minor component of the total fuel mixture, for example dual-fuel and flexible-fuel engines with diesel pilot injection, where the diesel pilot fuel mass is less than 5% of the total fuel mass and diesel exhaust fluid injection; consistent with good engineering judgment. (4) Calculate α, β, γ, δ w C w H w O w S w N α, β, γ, δ Eq. 1065.655-20 Eq. 1065.655-21 Eq. 1065.655-22 Eq. 1065.655-23 Where: N j j m j j. w Hmeas j j. w Cmeas j j. w Omeas j j. w Smeas j j. w Nmeas j j. Example: N j m 1 w Hmeas1 w Cmeas1 w Omeas1 w Smeas1 w Nmeas1 M C M H M O M S M N (5) Table 2 follows: (f) Calculated raw exhaust molar flow rate from measured intake air molar flow rate or fuel mass flow rate. n exh n int m fuel n int m fuel (1) Crankcase flow rate. n int m fuel (i) You may measure flow rate through the crankcase vent and subtract it from the calculated exhaust flow. (ii) You may estimate flow rate through the crankcase vent by engineering analysis as long as the uncertainty in your calculation does not adversely affect your ability to show that your engines comply with applicable emission standards. (iii) You may assume your crankcase vent flow rate is zero. (2) Intake air molar flow rate calculation. n exh n int Where: n exh n int Example: n int x int/exhdry x raw/exhdry x H20exhdry (3) Fluid mass flow rate calculation. Where: n exh j j N m j j. w Cj j. Example: N j m 1 w C1 M C x Ccombdry1 x H20exhdry1 n exh (g) Calculated raw exhaust molar flow rate from measured intake air molar flow rate, dilute exhaust molar flow rate, and dilute chemical balance. n exh n int n dexh n int n dexh n exh (1) Crankcase flow rate. (2) Dilute exhaust and intake air molar flow rate calculation. n exh Example: n int x raw/exhdry x int/exhdry x H20/exh n dexh n exh [73 FR 37331, June 30, 2008, as amended at 73 FR 59334, Oct. 8, 2008; 75 FR 23051, Apr. 30, 2010; 76 FR 57458, Sept. 15, 2011; 79 FR 23799, Apr. 28, 2014; 81 FR 74182, Oct. 25, 2016; 86 FR 34563, June 29, 2021; 87 FR 64866, Oct. 26, 2022; 88 FR 4684, Jan. 24, 2023; 89 FR 29808, Apr. 22, 2024] § 1065.656 Hydrogen-based chemical balances of fuel, DEF, intake air, and exhaust. (a) General. (b) Procedures that require chemical balances. (1) A value proportional to total work, when you choose to determine brake-specific emissions as described in § 1065.650(f). (2) Raw exhaust molar flow rate either from measured intake air molar flow rate or from fuel mass flow rate as described in paragraph (f) of this section. (3) Raw exhaust molar flow rate from measured intake air molar flow rate and dilute exhaust molar flow rate as described in paragraph (g) of this section. (4) The amount of water in a raw or diluted exhaust flow, x H2Oexh (5) The calculated total dilution air flow when you do not measure dilution air flow to correct for background emissions as described in § 1065.667(c) and (d). (c) Chemical balance procedure. x H2exhdry x dil/exhdry x int/exhdry x, x H2Oexh x dry x H2Oexhdry w C w H w O w S w N w C H w O S w N (1) Convert your measured concentrations such as x H2meas NH3meas x CO2meas x COmeas x THCmeas x O2meas x H2meas x NOmeas x NO2meas x H2Oint x H2Omeas x H2OxO2meas x H2OxNOmeas x H2Oint x H2Oexh X 2 X 2 X X x NOx 2 2 x NOx 2. X 2 X 2 X (2) Enter the equations in paragraph (c)(5) of this section into a computer program to iteratively solve for x H2exhdry x dil/exhdry x int/exhdry x H2exhdry x dil/exhdry x int/exhdry x int/exhdry x dil/exhdry (3) Use the following symbols and subscripts in the equations for performing the chemical balance calculations in this paragraph (c): Table 1 to Paragraph ( c x [emission]meas Amount of measured emission in the sample at the respective gas analyzer. x [emission]exh Amount of emission per dry mole of exhaust. x [emission]exhdry Amount of emission per dry mole of dry exhaust. x H2O[emission]meas Amount of H 2 x Ccombdry Amount of carbon from fuel and any injected fluids in the exhaust per mole of dry exhaust. x Hcombdry Amount of hydrogen from fuel and any injected fluids in the exhaust per mole of dry exhaust. x dil/exh Amount of dilution gas or excess air per mole of exhaust. x dil/exhdry amount of dilution gas and/or excess air per mole of dry exhaust. x Hcombdry Amount of hydrogen from fuel and any injected fluids in the exhaust per mole of dry exhaust. x int/exhdry Amount of intake air required to produce actual combustion products per mole of dry (raw or diluted) exhaust. x raw/exhdry Amount of undiluted exhaust, without excess air, per mole of dry (raw or diluted) exhaust. x CO2int Amount of intake air CO 2 x CO2intdry amount of intake air CO 2 x CO2intdry x H2Oint Amount of H 2 x H2Ointdry Amount of intake air H 2 x O2int Amount of intake air O 2 x CO2dil Amount of dilution gas CO 2 x CO2dildry Amount of dilution gas CO 2 x CO2dildry x H2Odil Amount of dilution gas H 2 x H2Odildry Amount of dilution gas H 2 τ Effective carbon content of the fuel and any injected fluids. χ Effective hydrogen content of the fuel and any injected fluids. ϕ Effective oxygen content of the fuel and any injected fluids. ξ Effective sulfur content of the fuel and any injected fluids. ω Effective nitrogen content of the fuel and any injected fluids. w C Carbon mass fraction of the fuel (or mixture of test fuels) and any injected fluids. w H Hydrogen mass fraction of the fuel (or mixture of test fuels) and any injected fluids. w O Oxygen mass fraction of the fuel (or mixture of test fuels) and any injected fluids. w S Sulfur mass fraction of the fuel (or mixture of test fuels) and any injected fluids. w N Nitrogen mass fraction of the fuel (or mixture of test fuels) and any injected fluids. (4) Use the equations specified in this section to iteratively solve for x int/exhdry x dil/exhdry x H2exhdry (i) For x H2exhdry (ii) The calculation of x O2exhdry x O2meas (iii) The calculation of x NH3exhdry 3 x NH3exhdry (iv) The calculation of x CO2exhdry 2 x CO2exhdry x Ccombdry x COexhdry x THCexhdry x COexhdry x THCexhdry x N2Oexhdry 2 x N2Oexhdry (5) The chemical balance equations are as follows: x Ccombdry x co2exhdry x coexhdry x THCexhdry x co2dil x dil/exhdry x co2int x int/exhdry Eq. 1065.656-1 Eq. 1065.656-2 Eq. 1065.656-3 Eq. 1065.656-4 Eq. 1065.656-5 Eq. 1065.656-6 (see table 2 of this section) Eq. 1065.656-7 (see table 2 of this section) Eq. 1065.656-8 Eq. 1065.656-9 Eq. 1065.656-10 Eq. 1065.656-11 Eq. 1065.656-12 Eq. 1065.656-13 Eq. 1065.656-14 Eq. 1065.656-15 Eq. 1065.656-16 (see table 2 of this section) Eq. 1065.656-17 Eq. 1065.656-18 Eq. 1065.656-19 Eq. 1065.656-20 Eq. 1065.656-21 Eq. 1065.656-22 Eq. 1065.656-23 (6) Depending on your measurements, use the equations and guess the quantities specified in the following table: Table 2 to Paragraph ( c When measuring Guess . . . Calculate . . . (i) x O2meas x int/exhdry x H2exhdry (A) x H2exhdry (B) x O2exhdry (ii) x H2meas x int/exhdry x dil/exhdry (A) x H2exhdry (B) [Reserved] (7) The following example is a solution for x int/exhdry, x dil/exhdry, x HOexhdry (d) Mass fractions of fuel. W C W H W O W S W N, W C W H W O W S W N Eq. 1065.656-24 Eq. 1065.656-25 Eq. 1065.656-26 Eq. 1065.656-27 Eq. 1065.656-28 Where: w C w H w O w S w N τ M C χ M H ϕ M O ξ M S ω M N Example for NH 3 fuel: τ χ ϕ ξ ω M C M H M O M S M N w C w H w O w S w N (2) For carbon-containing fuels and diesel exhaust fluid determine the mass fractions of fuel, W C W H W O W S W N W C W H W O W S W N Eq. 1065.656-29 Eq. 1065.656-30 Eq. 1065.656-31 Eq. 1065.656-32 Eq. 1065.656-33 Where: w C w H w O w S w N M C α M H β M O γ M S δ M N Example: α β γ δ M C M H M O M S M N (3) For nonconstant fuel mixtures, you must account for the varying proportions of the different fuels. This paragraph (d)(3) generally applies for dual-fuel and flexible-fuel engines, but optionally it may also be applied if diesel exhaust fluid or other fluids injected into the exhaust are injected in a way that is not strictly proportional to fuel flow. Account for these varying concentrations either with a batch measurement that provides averaged values to represent the test interval, or by analyzing data from continuous mass rate measurements. Application of average values from a batch measurement generally applies to situations where one fluid is a minor component of the total fuel mixture; consistent with good engineering judgment. Calculate W C W H W O W S W N Eq. 1065.656-34 Eq. 1065.656-35 Eq. 1065.656-36 Eq. 1065.656-37 Eq. 1065.656-38 Where: w C w H w O w S w N N j j m j j. w Cmeasj j. w Hmeasj j. w Omeasj j. w Smeasj j. w Nmeasj j. Example for a mixture of diesel and NH 3 fuel where diesel represents 15% of energy: N m 1 m 2 w Cmeas1 w Hmeas1 w Omeas1 w Smeas1 w Nmeas1 w Cmeas2 w Hmeas2 w Omeas2 w Smeas2 w Nmeas2 w C w H w O w S w N (e) Fuel and diesel exhaust fluid composition. α, β, γ, δ, (2) For fuels other than carbon-containing fuels use the default values for τ, χ, ϕ, ξ, ω τ, ϕ, ξ, ω τ, ϕ, ξ, ω χ (3) If your fuel mixture contains carbon-containing fuels and your testing requires fuel composition values referencing carbon, calculate α, β, γ, δ Table 3 to Paragraph (e)(4) Fuel Atomic carbon, oxygen, and nitrogen-to-hydrogen ratios Ct,Hx,Oq,Sj,Nv Hydrogen C 0 2 o o o Ammonia C 0 3 o o 1 (f) Calculated raw exhaust molar flow rate from measured intake air molar flow rate or fuel mass flow rate. (1) Crankcase flow rate. (i) You may measure flow rate through the crankcase vent and subtract it from the calculated exhaust flow. (ii) You may estimate flow rate through the crankcase vent by engineering analysis as long as the uncertainty in your calculation does not adversely affect your ability to show that your engines comply with applicable emission standards. (iii) You may assume your crankcase vent flow rate is zero. (2) Intake air molar flow rate calculation. n Eq. 1065.656-39 Where: n exh n int Example: n int x int/exhdry x raw/exhdry x H20exhdry (3) Fluid mass flow rate calculation. Eq. 1065.656-40 Where: n exh j j N m j j. w Cj j. w Hj j. Example: x H20exhdry1 M C M H x Ccombdry1 x Hcombdry1 m 1 m 2 w C1 w C2 w H1 w H2 N (g) Calculated raw exhaust molar flow rate from measured intake air molar flow rate, dilute exhaust molar flow rate, and dilute chemical balance. n exh n int n dexh n int n dexh n dexh (1) Crankcase flow rate. (2) Dilute exhaust and intake air molar flow rate calculation. Calculate as follows: n exh x raw/exhdry x int/exhdry x H20exh n dexh n int Eq. 1065.656-41 Example: n int x raw/exhdry x int/exhdry x H20exhdry n dexh n exh [89 FR 29810, Apr. 22, 2024, as amended at 89 FR 51238, June 17, 2024] § 1065.659 Removed water correction. (a) If you remove water upstream of a concentration measurement, x x H2O[emission]meas x H2Oexh x H2O[emission]meas x H2Oexh x H2Oexh x H2Oexh x H2Oexh (b) Determine the amount of water remaining downstream of a sample dryer and at the concentration measurement using one of the methods described in § 1065.145(e)(2). If you use a sample dryer upstream of an analyzer and if the calculated amount of water remaining downstream of the sample dryer and at the concentration measurement, x H2O[emission]meas x H2Oexh x H2O[emission]meas x H2Oexh i.e., x H2Oexh x H2O[emission]meas (c) For a concentration measurement where you did not remove water, you may set x H2O[emission]meas x H2Oexh x H2Oexh (1) Measure the dewpoint and absolute pressure and calculate the amount of water as described in § 1065.645. (2) If the measurement comes from raw exhaust, you may determine the amount of water based on intake-air humidity, plus a chemical balance of fuel, DEF, intake air, and exhaust as described in § 1065.655. (3) If the measurement comes from diluted exhaust, you may determine the amount of water based on intake-air humidity, dilution air humidity, and a chemical balance of fuel, DEF, intake air, and exhaust as described in § 1065.655. (d) Perform a removed water correction to the concentration measurement using the following equation: [73 FR 37335, June 30, 2008, as amended at 76 FR 57462, Sept. 15, 2011; 79 FR 23804, Apr. 28, 2014; 86 FR 34566, June 29, 2021] § 1065.660 THC, NMHC, NMNEHC, CH 4 2 6 (a) THC determination and initial THC/CH 4 contamination corrections. x THC[THC-FID]cor x THC[THC-FID]init x THC[THC-FID]cor x THC[THC-FID]uncor x THC[THC-FID]init Eq. 1065.660-1 Example: x THCuncor x THCinit x THCcor x THCcor (2) For the NMHC determination described in paragraph (b) of this section, correct x THC[THC-FID] x THC[NMC-FID] 4 4 (3) For the NMNEHC determination described in paragraph (c) of this section, correct x THC[THC-FID] x THC[NMC-FID] 4 4 (4) For the CH 4 x THC[NMC-FID] 4 4 (5) You may calculate THC as the sum of NMHC and CH 4 4 (6) You may calculate THC as the sum of NMNEHC, C 2 6 4 4 2 6 (b) NMHC determination. x NMHC (1) If you do not measure CH 4 (2) For an NMC, calculate x NMHC 4 RF CH4[THC-FID], x THC[THC-FID]cor, 4 x THC[NMC-FID]cor, (i) Use the following equation for an NMC configured as described in § 1065.365(d): Eq. 1065.660-2 Where: x NMHC x THC[THC-FID]cor x THC[NMC-FID]cor RF CH4[THC-FID] 4, RFPF C2H6[NMC-FID] 2 6 RFPF CH4[NMC-FID] 4 Example: x THC[THC-FID]cor x THC[NMC-FID]cor RFPF C2H6[NMC-FID] RFPF CH4[NMC-FID] RF CH4[THC-FID] (ii) Use the following equation for penetration fractions determined using an NMC configuration as outlined in § 1065.365(e): Eq. 1065.660-3 Where: x NMHC x THC[THC-FID]cor PF CH4[NMC-FID] 4 x THC[NMC-FID]cor PF C2H6[NMC-FID] 2 6 Example: x THC[THC-FID]cor PF CH4[NMC-FID] x THC[NMC-FID]cor PF C2H6[NMC-FID] (iii) Use the following equation for an NMC configured as described in § 1065.365(f): Eq. 1065.660-4 Where: x NMHC x THC[THC-FID]cor PF CH4[NMC-FID] 4 x THC[NMC-FID]cor RFPF C2H6[NMC-FID] 2 6 RF CH4[THC-FID] 4, Example: x THC[THC-FID]cor PF CH4[NMC-FID] x THC[NMC-FID]cor RFPF C2H6[NMC-FID] RF CH4[THC-FID] (3) For a GC-FID or FTIR, calculate x NMHC 4 RF CH4[THC-FID], x THC[THC-FID]cor, χ NMHC THC[THC-FID]cor RF CH4[THC-FID] CH4 Eq. 1065.660-5 Where: x NMHC x THC[THC-FID]cor RF CH4[THC-FID] 4. x CH4 4, Example: x THC[THC-FID]cor RF CH4[THC-FID] x CH4 x NMHC x NMHC (4) For an FTIR, calculate x NMHC Eq. 1065.660-6 Where: x NMHC x HCi 1 x HCi-init 1 Example: x C2H6 x C2H4 x C2H2 x C3H8 x C3H6 x C4H10 x CH2O x C2H4O x CH2O2 x CH4O x NMHC x NMHC (c) NMNEHC determination. x NMNEHC (1) Calculate x NMNEHC (i) If the content of your test fuel contains less than 0.010 mol/mol of ethane, you may omit the calculation of NMNEHC concentration and calculate the mass of NMNEHC as described in § 1065.650(c)(6)(i). (ii) If the content of your fuel test contains at least 0.010 mol/mol of C 2 6 (2) For a GC-FID, NMC FID, or FTIR, calculate x NMNEHC 4 RF CH4[THC-FID], 2 6 RF C2H6[THC-FID], x THC[THC-FID]cor, 4 x CH4, 2 6 x C2H6, x NMNEHC x THC[THC-FID}cor CH4{THC-FID} x CH4 C2H6{THC-FID] x C2H6 Eq. 1065.660-7 Where: x NMNEHC x THC[THC-FID]cor RF CH4[THC-FID] 4. x CH4 4, RF C2H6[THC-FID] 2 6. x C2H6 1 2 6, Example: x THC[THC-FID]cor RF CH4[THC-FID] x CH4 RF C2H6[THC-FID] x C2H6 x NMNEHC x NMNEHC (3) For an FTIR, calculate x NMNEHC Eq. 1065.660-8 Where: x NMNEHC x HC i 1 i x HC i -init 1 i, Example: x C2H4 x C2H2 x C3H8 x C3H6 x C4H10 x CH2O x C2H4O x CH2O2 x CH4O x NMNEHC x NMNEHC (d) CH 4 4 x CH4 (1) For an NMC, calculate x CH4 4 RF CH4[THC-FID], x THC[THC-FID]cor, 4 x THC[NMC-FID]cor, (i) Use the following equation for an NMC configured as described in § 1065.365(d): Eq. 1065.660-9 Where: x CH4 4 x THC[NMC-FID]cor x THC[THC-FID]cor RFPF C2H6[NMC-FID] 2 6 RF CH4[THC-FID] 4, RFPF CH4[NMC-FID] 4 Example: x THC[NMC-FID]cor x THC[THC-FID]cor RFPF C2H6[NMC-FID] RFPF CH4[NMC-FID] RF CH4[THC-FID] (ii) Use the following equation for an NMC configured as described in § 1065.365(e): Eq. 1065.660-10 Where: x CH4 4. x THC[NMC-FID]cor x THC[THC-FID]cor PF C2H6[NMC-FID] 2 6 RF CH4[THC-FID] 4, PF CH4[NMC-FID] 4 Example: x THC[NMC-FID]cor x THC[THC-FID]cor PF C2H6[NMC-FID] RF CH4[THC-FID] PF CH4[NMC-FID] (iii) Use the following equation for an NMC configured as described in § 1065.365(f): Eq. 1065.660-11 Where: x CH4 4. x THC[NMC-FID]cor x THC[THC-FID]cor RFPF C2H6[NMC-FID] 2 6 PF CH4[NMC-FID] 4 RF CH4[THC-FID] 4, Example: x THC[NMC-FID]cor x THC[THC-FID]cor RFPF C2H6[NMC-FID] PF CH4[NMC-FID] RF CH4[THC-FID] (2) For a GC-FID or FTIR, x CH4 4 (e) C 2 6 x C2H6 1 2 6 [89 FR 29819, Apr. 22, 2024] § 1065.665 THCE and NMHCE determination. (a) If you measured an oxygenated hydrocarbon's mass concentration, first calculate its molar concentration in the exhaust sample stream from which the sample was taken (raw or diluted exhaust), and convert this into a C 1 1 Where: χ THCE 1 χ NOTHC 1 χOHCi = the C 1 i χ OHCi-init 1 i χ THC[THC-FID]cor 1 RF OHCi[THC-FID] i 1 M dexh m dexhOHCi i M OHCi 1 i m dexh n dexhOHCi i n dexh (b) If we require you to determine nonmethane hydrocarbon equivalent (NMHCE), use the following equation: Where: x NMHCE 1 RF CH4[THC-FID] 4 x CH4 4, (c) The following example shows how to determine NMHCE emissions based on ethanol (C 2 5 3 2 4 2 1 x THC[THC-FID]cor x CH4 x C2H5OH x CH3OH x C2H4O x CH2O RF CH4[THC-FID] RF C2H5OH[THC-FID] RF CH3OH[THC-FID] RF H2H4O[THC-FID] RF CH2O[THC-FID] x NMHCE x THC[THC-FID]cor x C2H5OH RF C2H5OH[THC-FID] x CH3OH RF CH3OH[THC-FID] x C2H4O RF C2H4O[THC-FID] x CH2O RF CH2O[THC-FID] x C2H5OH x CH3OH x C2H4O x CH2O RF CH4[THC-FID] x CH4 x NMHCE x NMHCE [79 FR 23805, Apr. 28, 2014, as amended at 81 FR 74187, Oct. 25, 2016; 86 FR 34567, June 29, 2021] § 1065.667 Dilution air background emission correction. (a) To determine the mass of background emissions to subtract from a diluted exhaust sample, first determine the total flow of dilution air, n dil, i.e., e.g., M, n dil M, m. m PM. (b) You may determine the total flow of dilution air by a direct flow measurement. (c) You may determine the total flow of dilution air by subtracting the calculated raw exhaust molar flow as described in § 1065.655(g) from the measured dilute exhaust flow. This may be done by totaling continuous calculations or by using batch results. (d) You may determine the total flow of dilution air from the measured dilute exhaust flow and a chemical balance of the fuel, DEF, intake air, and dilute exhaust as described in § 1065.655. For this paragraph (d), the molar flow of dilution air is calculated by multiplying the dilute exhaust flow by the mole fraction of dilution gas to dilute exhaust, χ dil/ex n dexh dil/exh dil/exh (e) The following is an example of using the flow-weighted mean fraction of dilution air in diluted exhaust, x dil/exh n dexh Example: M NOx x bkgnd −6 n dexh x dil/exh m bkgndNOxdexh −6 m bkgndNOxdexh m bkgndNOx m bkgndNOx (f) The following is an example of using the fraction of dilution air in diluted exhaust, x dil/exh n dexh Example: M NOx x bkgnd −6 n dexh x dil/exh m bkgndNOxdexh −6 m bkgndNOxdexh m bkgndNOx m bkgndNOx [76 FR 57465, Sept. 15, 2011, as amended at 81 FR 74188, Oct. 25, 2016; 86 FR 34567, June 29, 2021; 88 FR 4686, Jan. 24, 2023] § 1065.670 NO X See the standard-setting part to determine if you may correct NO X X X X X X (a) For compression-ignition engines operating on carbon-containing fuels and lean-burn combustion engines operating on fuels other than carbon-containing fuels, correct for intake-air humidity using the following equation: Example: x NOxuncor x H2O x NOxcor x NOxcor (b) For spark-ignition engines operating on carbon-containing fuels and stoichiometric combustion engines operating on fuels other than carbon-containing fuels, correct for intake-air humidity using the following equation: Example: x NOxuncor x H2O x NOxcor x NOxcor (c) Develop your own correction, based on good engineering judgment. [75 FR 23056, Apr. 30, 2010, as amended at 76 FR 57466, Sept. 15, 2011; 88 FR 4686, Jan. 24, 2023; 89 FR 29822, Apr. 22, 2024] § 1065.672 Drift correction. (a) Scope and frequency. (b) Correction principles. (c) Drift validation. (d) Drift correction. (1) Correct each recorded concentration, x i x (2) Correct for drift using the following equation: Where: x idriftcorrected x refzero x refspan x prespan x postspan x i x x prezero x postzero Example: x refzero x refspan x prespan x postspan x i x x prezero x postzero x idriftcorrected (3) For any pre-test interval concentrations, use the last concentration determined before the test interval. For some test intervals, the last pre-zero or pre-span might have occurred before one or more earlier test intervals. (4) For any post-test interval concentrations, use the first concentration determined after the test interval. For some test intervals, the first post-zero or post-span might occur after one or more later test intervals. (5) If you do not record any pre-test interval analyzer response to the span gas concentration, x prespan x prespan x prespan x refspan (6) If you do not record any pre-test interval analyzer response to the zero gas concentration, x prezero x prezero x prezero x refzero (7) Usually the reference concentration of the zero gas, x refzero x refzero x refzero 2 2 x refzero x refzero x refzero x refzero [70 FR 40516, July 13, 2005, as amended at 74 FR 8427, Feb. 24, 2009; 75 FR 23056, Apr. 30, 2010; 88 FR 4686, Jan. 24, 2023; 89 FR 29823, Apr. 22, 2024] § 1065.675 CLD quench verification calculations. Perform CLD quench-check calculations as follows: (a) Perform a CLD analyzer quench verification test as described in § 1065.370. (b) Estimate the maximum expected mole fraction of water during emission testing, x H2Oexp. x H2Oexp x H2Omeas. (c) Estimate the maximum expected CO 2 x CO2exp 2 2 2 (d) Calculate quench as follows: Where: quench χ NOdry χ NOwet χ H2Oexp χ H2Omeas χ NOmeas 2 χ NOact 2 χ CO2exp 2 χ CO2act 2 2 Where: χ NOspan χ CO2span 2 Example: χ NOdry χ NOwet χ H2Oexp χ H2Omeas χ NOmeas χ NOspan χ CO2exp χ CO2span χ CO2act quench [73 FR 59340, Oct. 8, 2008, as amended at 76 FR 57466, Sept. 15, 2011; 81 FR 74188, Oct. 25, 2016; 86 FR 34568, June 29, 2021; 88 FR 4686, Jan. 24, 2023] § 1065.680 Adjusting emission levels to account for infrequently regenerating aftertreatment devices. This section describes how to calculate and apply emission adjustment factors for engines using aftertreatment technology with infrequent regeneration events that may occur during testing. These adjustment factors are typically calculated based on measurements conducted for the purposes of engine certification, and then used to adjust the results of testing related to demonstrating compliance with emission standards. For this section, “regeneration” means an intended event during which emission levels change while the system restores aftertreatment performance. For example, exhaust gas temperatures may increase temporarily to remove sulfur from an adsorber or SCR catalyst or to oxidize accumulated particulate matter in a trap. The duration of this event extends until the aftertreatment performance and emission levels have returned to normal baseline levels. Also, “infrequent” refers to regeneration events that are expected to occur on average less than once over a transient or ramped-modal duty cycle, or on average less than once per mode in a discrete-mode test. (a) Apply adjustment factors based on whether there is active regeneration during a test segment. The test segment may be a test interval or a full duty cycle, as described in paragraph (b) of this section. For engines subject to standards over more than one duty cycle, you must develop adjustment factors under this section for each separate duty cycle. You must be able to identify active regeneration in a way that is readily apparent during all testing. All adjustment factors for regeneration are additive. (1) If active regeneration does not occur during a test segment, apply an upward adjustment factor, UAF, UAF: Where: EF A[cycle] EF L[cycle] Example: EF ARMC EF LRMC UAF RMC (2) If active regeneration occurs or starts to occur during a test segment, apply a downward adjustment factor, DAF, DAF: Where: EF H[cycle] Example: EF ARMC EF HRMC DAF RMC (3) Note that emissions for a given pollutant may be lower during regeneration, in which case EF L EF H, UAF DAF (4) Calculate the average emission factor, EF A, Where: F [cycle] Example: F RMC EF ARMC (5) The frequency of regeneration, F, F Where: i r[cycle] i f[cycle] Example: i rRMC i fRMC (6) Use good engineering judgment to determine i r i f (i) For engines that are programmed to regenerate after a specific time interval, you may determine the duration of a regeneration event and the time between regeneration events based on the engine's design parameters. For other engines, determine these values based on measurements from in-use operation or from running repetitive duty cycles in a laboratory. (ii) For engines subject to standards over multiple duty cycles, such as for transient and steady-state testing, apply this same calculation to determine a value of F (iii) Consider an example for an engine that is designed to regenerate its PM filter 500 minutes after the end of the last regeneration event, with the regeneration event lasting 30 minutes. If the RMC takes 28 minutes, i rRMC i fRMC (b) Develop adjustment factors for different types of testing as follows: (1) Discrete-mode testing. EF H (2) Ramped-modal and transient testing. EF H EF H (3) Accounting for cold-start measurements. (i) Determine the frequency of regeneration, F (ii) Treat cold-start testing and hot-start testing together as a single test segment for adjusting measured emission results under this section. Apply the adjustment factor to the composite emission result. (iii) You may apply the adjustment factor only to the hot-start test result if your aftertreatment technology does not regenerate during cold operation as represented by the cold-start transient duty cycle. If we ask for it, you must demonstrate this by engineering analysis or by test data. (c) If an engine has multiple regeneration strategies, determine and apply adjustment factors under this section separately for each type of regeneration. [81 FR 74189, Oct. 25, 2016, as amended at 88 FR 4686, Jan. 24, 2023] § 1065.690 Buoyancy correction for PM sample media. (a) General. (b) PM sample media density. (1) For PTFE-coated borosilicate glass, use a sample media density of 2300 kg/m 3 (2) For PTFE membrane (film) media with an integral support ring of polymethylpentene that accounts for 95% of the media mass, use a sample media density of 920 kg/m 3 (3) For PTFE membrane (film) media with an integral support ring of PTFE, use a sample media density of 2144 kg/m 3 (c) Air density. (d) Calibration weight density. 3 (e) Correction calculation. Where: m cor m uncor r air r weight r media Where: p abs M mix R T amb [70 FR 40516, July 13, 2005, as amended at 73 FR 37339, June 30, 2008; 75 FR 23056, Apr. 30, 2010; 79 FR 23805, Apr. 28, 2014; 81 FR 74191, Oct. 25, 2016] § 1065.695 Data requirements. (a) To determine the information we require from engine tests, refer to the standard-setting part and request from your EPA Program Officer the format used to apply for certification or demonstrate compliance. We may require different information for different purposes, such as for certification applications, approval requests for alternate procedures, selective enforcement audits, laboratory audits, production-line test reports, and field-test reports. (b) See the standard-setting part and § 1065.25 regarding recordkeeping. (c) We may ask you the following about your testing, and we may ask you for other information as allowed under the Act: (1) What approved alternate procedures did you use? For example: (i) Partial-flow dilution for proportional PM. (ii) CARB test procedures. (iii) ISO test procedures. (2) What laboratory equipment did you use? For example, the make, model, and description of the following: (i) Engine dynamometer and operator demand. (ii) Probes, dilution, transfer lines, and sample preconditioning components. (iii) Batch storage media (such as the bag material or PM filter material). (3) What measurement instruments did you use? For example, the make, model, and description of the following: (i) Speed and torque instruments. (ii) Flow meters. (iii) Gas analyzers. (iv) PM balance. (4) When did you conduct calibrations and performance checks and what were the results? For example, the dates and results of the following: (i) Linearity verification. (ii) Interference checks. (iii) Response checks. (iv) Leak checks. (v) Flow meter checks. (5) What engine did you test? For example, the following: (i) Manufacturer. (ii) Family name on engine label. (iii) Model. (iv) Model year. (v) Identification number. (6) How did you prepare and configure your engine for testing? Consider the following examples: (i) Dates, hours, duty cycle and fuel used for service accumulation. (ii) Dates and description of scheduled and unscheduled maintenance. (iii) Allowable pressure range of intake restriction. (iv) Allowable pressure range of exhaust restriction. (v) Charge air cooler volume. (vi) Charge air cooler outlet temperature, specified engine conditions and location of temperature measurement. (vii) Fuel temperature and location of measurement. (viii) Any aftertreatment system configuration and description. (ix) Any crankcase ventilation configuration and description (e.g., open, closed, PCV, crankcase scavenged). (x) Number and type of preconditioning cycles. (7) How did you test your engine? For example: (i) Constant speed or variable speed. (ii) Mapping procedure (step or sweep). (iii) Continuous or batch sampling for each emission. (iv) Raw or dilute sampling; any dilution-air background sampling. (v) Duty cycle and test intervals. (vi) Cold-start, hot-start, warmed-up running. (vii) Absolute pressure, temperature, and dewpoint of intake and dilution air. (viii) Simulated engine loads, curb idle transmission torque value. (ix) Warm-idle speed value. (x) Simulated vehicle signals applied during testing. (xi) Bypassed governor controls during testing. (xii) Date, time, and location of test (e.g., dynamometer laboratory identification). (xiii) Cooling medium for engine and charge air. (xiv) Operating temperatures of coolant, head, and block. (xv) Natural or forced cool-down and cool-down time. (xvi) Canister loading. (8) How did you validate your testing? For example, results from the following: (i) Duty cycle regression statistics for each test interval. (ii) Proportional sampling. (iii) Drift. (iv) Reference PM sample media in PM-stabilization environment. (v) Carbon balance error verification, if performed. (9) How did you calculate results? For example, results from the following: (i) Drift correction. (ii) Noise correction. (iii) “Dry-to-wet” correction. (iv) NMHC, CH 4 (v) Chemical balance method—carbon-based or hydrogen-based chemical balance method. (vi) NO X (vii) Brake-specific emission formulation—total mass divided by total work, mass rate divided by power, or ratio of mass to work. (viii) Rounding emission results. (10) What were the results of your testing? For example: (i) Maximum mapped power and speed at maximum power. (ii) Maximum mapped torque and speed at maximum torque. (iii) For constant-speed engines: no-load governed speed. (iv) For constant-speed engines: test torque. (v) For variable-speed engines: maximum test speed. (vi) Speed versus torque map. (vii) Speed versus power map. (viii) Brake-specific emissions over the duty cycle and each test interval. (ix) Brake-specific fuel consumption. (11) What fuel did you use? For example: (i) Fuel that met specifications of subpart H of this part. (ii) Alternate fuel. (iii) Oxygenated fuel. (12) How did you field test your engine? For example: (i) Data from paragraphs (c)(1), (3), (4), (5), and (9) of this section. (ii) Probes, dilution, transfer lines, and sample preconditioning components. (iii) Batch storage media (such as the bag material or PM filter material). (iv) Continuous or batch sampling for each emission. (v) Raw or dilute sampling; any dilution air background sampling. (vi) Cold-start, hot-start, warmed-up running. (vii) Intake and dilution air absolute pressure, temperature, dewpoint. (viii) Curb idle transmission torque value. (ix) Warm idle speed value, any enhanced-idle speed value. (x) Date, time, and location of test (e.g., identify the testing laboratory). (xi) Proportional sampling validation. (xii) Drift validation. (xiii) Operating temperatures of coolant, head, and block. (xiv) Vehicle make, model, model year, identification number. [70 FR 40516, July 13, 2005, as amended at 73 FR 37339, June 30, 2008; 79 FR 23807, Apr. 28, 2014; 86 FR 34568, June 29, 2021; 88 FR 4687, Jan. 24, 2023; 89 FR 29823, Apr. 22, 2024] Subpart H—Engine Fluids, Test Fuels, Analytical Gases and Other Calibration Standards § 1065.701 General requirements for test fuels. (a) General. (b) Fuels meeting alternate specifications. (c) Fuels not specified in this subpart. (1) For engines designed to operate on a single fuel, we will generally allow you to use the fuel if you show us all the following things are true: (i) Show that your engines will use only the designated fuel in service. (ii) Show that this type of fuel is commercially available. (iii) Show that operating the engines on the fuel we specify would be inappropriate, as in the following examples: (A) The engine will not run on the specified fuel. (B) The engine or emission controls will not be durable or work properly when operating with the specified fuel. (C) The measured emission results would otherwise be substantially unrepresentative of in-use emissions. (2) For engines that are designed to operate on different fuel types, the provisions of paragraphs (c)(1)(ii) and (iii) of this section apply with respect to each fuel type. (3) For engines that are designed to operate on different fuel types as well as continuous mixtures of those fuels, we may require you to test with either the worst-case fuel mixture or the most representative fuel mixture, unless the standard-setting part specifies otherwise. (d) Fuel specifications. (1) Measure and calculate values as described in the appropriate reference procedure. Record and report final values expressed to at least the same number of decimal places as the applicable limit value. The right-most digit for each limit value is significant unless specified otherwise. For example, for a specified distillation temperature of 60 °C, determine the test fuel's value to at least the nearest whole number. (2) The fuel parameters specified in this subpart depend on measurement procedures that are incorporated by reference. For any of these procedures, you may instead rely upon the procedures identified in 40 CFR part 1090 for measuring the same parameter. For example, we may identify different reference procedures for measuring gasoline parameters in 40 CFR 1090.1360. (e) Two-stroke fuel/oil mixing. For two-stroke engines, use a fuel/oil mixture meeting the manufacturer's specifications. (f) Service accumulation and field testing fuels. Table 1 of § 1065.701—Examples of Service-Accumulation and Field-Testing Fuels Fuel category Subcategory Reference procedure a Diesel Light distillate and light blends with residual ASTM D975. Middle distillate ASTM D6985. Biodiesel (B100) ASTM D6751. Intermediate and residual fuel All See § 1065.705. Gasoline Automotive gasoline ASTM D4814. Automotive gasoline with ethanol concentration up to 10 volume % ASTM D4814. Alcohol Ethanol (E51-83) ASTM D5798. Methanol (M70-M85) ASTM D5797. Aviation fuel Aviation gasoline ASTM D910. Gas turbine ASTM D1655. Jet B wide cut ASTM D6615. Gas turbine fuel General ASTM D2880. a [70 FR 40516, July 13, 2005, as amended at 73 FR 37339, June 30, 2008; 73 FR 59341, Oct. 8, 2008; 75 FR 23057, Apr. 30, 2010;79 FR 23807, Apr. 28, 2014; 85 FR 78468, Dec. 4, 2020; 86 FR 34568, June 29, 2021] § 1065.703 Distillate diesel fuel. (a) Distillate diesel fuels for testing must be clean and bright, with pour and cloud points adequate for proper engine operation. (b) There are three grades of #2 diesel fuel specified for use as a test fuel. See the standard-setting part to determine which grade to use. If the standard-setting part does not specify which grade to use, use good engineering judgment to select the grade that represents the fuel on which the engines will operate in use. The three grades are specified in Table 1 of this section. Table 1 of § 1065.703—Test Fuel Specifications for Distillate Diesel Fuel Property Unit Ultra low Low High Reference procedure a Cetane Number 40-50 40-50 40-50 ASTM D613. Distillation range: Initial boiling point °C 171-204 171-204 171-204 ASTM D86. 10 pct. point 204-238 204-238 204-238 50 pct. point 243-282 243-282 243-282 90 pct. point 293-332 293-332 293-332 Endpoint 321-366 321-366 321-366 Gravity °API 32-37 32-37 32-37 ASTM D4052. Total sulfur mg/kg 7-15 300-500 800-2500 ASTM D2622, ASTM D5453, or ASTM D7039. Aromatics, min. (Remainder shall be paraffins, naphthenes, and olefins) g/kg 100 100 100 ASTM D5186. Flashpoint, min. °C 54 54 54 ASTM D93. Kinematic Viscosity mm 2 2.0-3.2 2.0-3.2 2.0-3.2 ASTM D445. a (c) You may use the following nonmetallic additives with distillate diesel fuels: (1) Cetane improver. (2) Metal deactivator. (3) Antioxidant, dehazer. (4) Rust inhibitor. (5) Pour depressant. (6) Dye. (7) Dispersant. (8) Biocide. [70 FR 40516, July 13, 2005, as amended at 73 FR 37340, June 30, 2008; 73 FR 59341, Oct. 8, 2008; 75 FR 23057, Apr. 30, 2010; 77 FR 2464, Jan. 18, 2012;79 FR 23807, Apr. 28, 2014; 85 FR 78468, Dec. 4, 2020; 86 FR 34569, June 29, 2021] § 1065.705 Residual and intermediate residual fuel. This section describes the specifications for fuels meeting the definition of residual fuel in 40 CFR 1090.80, including fuels marketed as intermediate fuel. Residual fuels for service accumulation and any testing must meet the following specifications: (a) The fuel must be a commercially available fuel that is representative of the fuel that will be used by the engine in actual use. (b) The fuel must be free of used lubricating oil. Demonstrate this by showing that the fuel meets at least one of the following specifications. (1) Zinc is at or below 15 mg per kg of fuel based on the procedures specified in IP—470, IP—501, or ISO 8217 (incorporated by reference, see § 1065.1010). (2) Phosphorus is at or below 15 mg per kg of fuel based on the procedures specified in IP—500, IP—501, or ISO 8217 (incorporated by reference, see § 1065.1010). (3) Calcium is at or below 30 mg per kg of fuel based on the procedures specified in IP—470, IP—501, or ISO 8217 (incorporated by reference, see § 1065.1010). (c) The fuel must meet the specifications for one of the categories in the following table: [79 FR 23808, Apr. 28, 2014, as amended at 85 FR 78468, Dec. 4, 2020; 86 FR 34569, June 29, 2021; 89 FR 29823, Apr. 22, 2024] § 1065.710 Gasoline. (a) This section specifies test fuel properties for gasoline with ethanol (low-level blend only) and for gasoline without ethanol. Note that the “fuel type” for the fuels specified in paragraphs (b) and (c) of this section is considered to be gasoline. In contrast, fuels with higher ethanol concentrations, such as fuel containing 82 percent ethanol, are considered to be ethanol fuels rather than gasoline. We specify some test fuel parameters that apply uniquely for low-temperature testing and for testing at altitudes above 1,219 m. For all other testing, use the test fuel parameters specified for general testing. Unless the standard-setting part specifies otherwise, use the fuel specified in paragraph (c) of this section for general testing. (b) The following specifications apply for a blended gasoline test fuel that has nominally 10% ethanol (commonly called E10 test fuel): (1) Prepare the blended test fuel from typical refinery gasoline blending components. You may not use pure compounds, except as follows: (i) You may use neat ethanol as a blendstock. (ii) You may adjust the test fuel's vapor pressure by adding butane. (iii) You may adjust the test fuel's benzene content by adding benzene. (iv) You may adjust the test fuel's sulfur content by adding sulfur compounds that are representative of those found with in-use fuels. (2) Table 1 of this section identifies limit values consistent with the units in the reference procedure for each fuel property. These values are generally specified in international units. Values presented in parentheses are for information only. Table 1 follows: (3) The ethanol-blended specification in Table 1 of this section is based on the volume % ethanol content of the fuel as determined during blending by the fuel supplier and as stated by the supplier at the time of fuel delivery. Use good engineering judgment to determine the volume % of ethanol based on the volume of each blendstock. We recommend using a flow-based or gravimetric procedure that has an accuracy and repeatability of ±0.1%. (c) The specifications of this paragraph (c) apply for testing with neat gasoline. This is sometimes called indolene or E0 test fuel. Gasoline for testing must have octane values that represent commercially available fuels for the appropriate application. Test fuel specifications apply as follows: Table 2 of § 1065.710—Test Fuel Specifications for Neat (E0) Gasoline Property Unit Specification Reference procedure a General Low-temperature testing Distillation Range: Evaporated initial boiling point °C 24-35 b 24-36 ASTM D86. 10% evaporated °C 49-57 37-48 50% evaporated °C 93-110 82-101 90% evaporated °C 149-163 158-174 Evaporated final boiling point °C Maximum, 213 Maximum, 212 Total Aromatic Hydrocarbons volume % Maximum, 35 Maximum, 30.4 ASTM D1319 or ASTM D5769. Olefins c volume % Maximum, 10 Maximum, 17.5 ASTM D1319 or ASTM D6550. Lead g/liter Maximum, 0.013 Maximum, 0.013 ASTM D3237. Phosphorous g/liter Maximum, 0.0013 Maximum, 0.005 ASTM D3231. Total sulfur mg/kg Maximum, 80 Maximum, 80 ASTM D2622. Dry vapor pressure equivalent d kPa 60.0-63.4 b e 77.2-81.4 ASTM D5191. a b c d DVPE p T DVPE p T DVPE p T DVPE e (d) Use the high-octane gasoline specified in paragraph (b) of this section only for engines or vehicles for which the manufacturer conditions the warranty on the use of premium gasoline. [79 FR 23809, Apr. 28, 2014, as amended at 80 FR 9119, Feb. 19, 2015; 86 FR 34571, June 29, 2021] § 1065.715 Natural gas. (a) Except as specified in paragraph (b) of this section, natural gas for testing must meet the specifications in the following table: Table 1 of § 1065.715—Test Fuel Specifications for Natural Gas Property Value a Methane, CH 4 Minimum, 0.87 mol/mol. Ethane, C 2 6 Maximum, 0.055 mol/mol. Propane, C 3 8 Maximum, 0.012 mol/mol. Butane, C 4 10 Maximum, 0.0035 mol/mol. Pentane, C 5 12 Maximum, 0.0013 mol/mol. C 6 Maximum, 0.001 mol/mol. Oxygen Maximum, 0.001 mol/mol. Inert gases (sum of CO 2 2 Maximum, 0.051 mol/mol. a (b) In certain cases you may use test fuel not meeting the specifications in paragraph (a) of this section, as follows: (1) You may use fuel that your in-use engines normally use, such as pipeline natural gas. (2) You may use fuel meeting alternate specifications if the standard-setting part allows it. (3) You may ask for approval to use fuel that does not meet the specifications in paragraph (a) of this section, but only if using the fuel would not adversely affect your ability to demonstrate compliance with the applicable standards in this chapter. (c) When we conduct testing using natural gas, we will use fuel that meets the specifications in paragraph (a) of this section. (d) At ambient conditions, natural gas must have a distinctive odor detectable down to a concentration in air not more than one-fifth the lower flammable limit. [73 FR 37342, June 30, 2008, as amended at 79 FR 23811, Apr. 28, 2014; 86 FR 34573, June 29, 2021; 88 FR 4687, Jan. 24, 2023; 89 FR 29823, Apr. 22, 2024] § 1065.720 Liquefied petroleum gas. (a) Except as specified in paragraph (b) of this section, liquefied petroleum gas for testing must meet the specifications in the following table: Table 1 to Paragraph ( a Property Value Reference procedure a Propane, C3H8 Minimum, 0.85 m 3 3 ASTM D2163. Vapor pressure at 38 °C Maximum, 1400 kPa ASTM D1267 or b Butanes Maximum, 0.05 m 3 3 ASTM D2163. Butenes Maximum, 0.02 m 3 3 ASTM D2163. Pentenes and heavier Maximum, 0.005 m 3 3 ASTM D2163. Propene Maximum, 0.1 m 3 3 ASTM D2163. Residual matter (residue on evaporation of 100 ml oil stain observation) Maximum, 0.05 ml pass c ASTM D2158. Corrosion, copper strip Maximum, No. 1 ASTM D1838. Sulfur Maximum, 80 mg/kg ASTM D6667. Moisture content pass ASTM D2713. a b c (b) In certain cases you may use test fuel not meeting the specifications in paragraph (a) of this section, as follows: (1) You may use fuel that your in-use engines normally use, such as commercial-quality liquefied petroleum gas. (2) You may use fuel meeting alternate specifications if the standard-setting part allows it. (3) You may ask for approval to use fuel that does not meet the specifications in paragraph (a) of this section, but only if using the fuel would not adversely affect your ability to demonstrate compliance with the applicable standards in this chapter. (c) When we conduct testing using liquefied petroleum gas, we will use fuel that meets the specifications in paragraph (a) of this section. (d) At ambient conditions, liquefied petroleum gas must have a distinctive odor detectable down to a concentration in air not more than one-fifth the lower flammable limit. [73 FR 37342, June 30, 2008, as amended at 79 FR 23811, Apr. 28, 2014; 86 FR 34573, June 29, 2021; 88 FR 4687, Jan. 24, 2023] § 1065.725 High-level ethanol-gasoline blends. For testing vehicles capable of operating on a high-level ethanol-gasoline blend, create a test fuel as follows: (a) Add ethanol to an E10 fuel meeting the specifications described in § 1065.710 until the ethanol content of the blended fuel is between 80 and 83 volume %. (b) You may alternatively add ethanol to a gasoline base fuel with no ethanol if you can demonstrate that such a base fuel blended with the proper amount of ethanol would meet all the specifications for E10 test fuel described in § 1065.710, other than the ethanol content. (c) The ethanol used for blending must be either denatured fuel ethanol meeting the specifications in 40 CFR 1090.270, or fuel-grade ethanol with no denaturant. Account for the volume of any denaturant when calculating volumetric percentages. (d) The blended test fuel must have a dry vapor pressure equivalent between 41.5 and 45.1 kPa (6.0 and 6.5 psi) when measured using the procedure specified in § 1065.710. You may add commercial grade butane as needed to meet this specification. [79 FR 23811, Apr. 28, 2014, as amended at 85 FR 78468, Dec. 4, 2020] § 1065.735 Diesel exhaust fluid. (a) Use commercially available diesel exhaust fluid that represents the product that will be used in your in-use engines. (b) Diesel exhaust fluid for testing must generally conform to the specifications referenced in the definition of “diesel exhaust fluid” in § 1065.1001. Use marine-grade diesel exhaust fluid only for marine engines. [81 FR 74191, Oct. 25, 2016] § 1065.740 Lubricants. (a) Use commercially available lubricating oil that represents the oil that will be used in your engine in use. (b) You may use lubrication additives, up to the levels that the additive manufacturer recommends. § 1065.745 Coolants. (a) You may use commercially available antifreeze mixtures or other coolants that will be used in your engine in use. (b) For laboratory testing of liquid-cooled engines, you may use water with or without rust inhibitors. (c) For coolants allowed in paragraphs (a) and (b) of this section, you may use rust inhibitors and additives required for lubricity, up to the levels that the additive manufacturer recommends. § 1065.750 Analytical gases. Analytical gases must meet the accuracy and purity specifications of this section, unless you can show that other specifications would not affect your ability to show that you comply with all applicable emission standards. (a) Subparts C, D, F, and J of this part refer to the following gas specifications: (1) Use purified gases to zero measurement instruments and to blend with calibration gases. Use gases with contamination no higher than the highest of the following values in the gas cylinder or at the outlet of a zero-gas generator: (i) 2% contamination, measured relative to the flow-weighted mean concentration expected at the standard. For example, if you would expect a flow-weighted CO concentration of 100.0 µmol/mol, then you would be allowed to use a zero gas with CO contamination less than or equal to 2.000 µmol/mol. (ii) Contamination as specified in the following table: Table 1 to Paragraph ( a ii a Constituent Purified Air Purified N 2 THC (C 1 ≤ 0.05 µmol/mol ≤ 0.05 µmol/mol CO ≤ 1 µmol/mol ≤ 1 µmol/mol CO 2 ≤ 10 µmol/mol ≤ 10 µmol/mol O 2 0.205 to 0.215 mol/mol ≤ 2 µmol/mol NO X ≤ 0.02 µmol/mol ≤ 0.02 µmol/mol N 2 b ≤ 0.02 µmol/mol ≤ 0.02 µmol/mol H 2 c ≤ 1 µmol/mol ≤ 1 µmol/mol NH 3 d ≤ 1 µmol/mol ≤ 1 µmol/mol H 2 e ≤ 5 µmol/mol ≤ 5 µmol/mol a b 2 2 2 c 2 2 d 3 3 e 2 (2) Use the following gases with a FID analyzer: (i) FID fuel. 2 2 4 2 4 (ii) FID burner air. (iii) FID zero gas. 2 2 (iv) FID propane span gas. 3 8 1 3 8 2 2 (v) FID CH 4 span gas. 4 4 1 4 2 2 (3) Use the following gas mixtures, with gases traceable within ±1% of the NIST-accepted gas standard value or other gas standards we approve: (i) CH 4 2 (ii) C 2 6 2 (iii) C 3 8 2 (iv) CO, balance purified N 2 (v) CO 2 2 (vi) NO, balance purified N 2 (vii) NO 2 (viii) O 2 2 (ix) C 3 8 2 2 (x) C 3 8 4 2 2 (xi) N 2 2 (xii) CH 4 2 6 2 (xiii) CH 4 2 2 2 2 2 4 2 4 2 6 3 8 3 6 4 4 10 2 (4) You may use gases for species other than those listed in paragraph (a)(3) of this section (such as methanol in air, which you may use to determine response factors), as long as they are traceable to within ±3% of the NIST-accepted value or other similar standards we approve, and meet the stability requirements of paragraph (b) of this section. (5) You may generate your own calibration gases using a precision blending device, such as a gas divider, to dilute gases with purified N 2 (6) If you measure H 2 2 2 x H2Oref 2 2 x H2Oref U xH2O 2 (i) Bubble gas that meets the requirements of paragraph (a)(1) of this section through distilled H 2 2 2 p abs T dew 2 2 U xH2O Eq. 1065.750-1 Eq. 1065.750-2 Eq. 1065.750-3 Where: T dew U T dew p abs U Pabs Example: T dew U T dew p abs U Pabs Using Eq. 1065.645-1, x H2O (ii) Use a device that introduces a measured flow of distilled H 2 2 (A) Calculate the amount of H 2 Eq. 1065.750-4 (B) Calculate the uncertainty of the amount of H 2 U xH2O, Eq. 1065.750-5 Eq. 1065.750-6 Eq. 1065.750-7 Where: n gas U n gas n H2O 2 U n H2O x H2O 2 U X H2O 2 (C) The following example is a solution for using the equations in paragraph (a)(6)(ii)(B) of this section: n H2O U n gas n gas U n H2O (b) Record the concentration of any calibration gas standard and its expiration date specified by the gas supplier. (1) Do not use any calibration gas standard after its expiration date, except as allowed by paragraph (b)(2) of this section. (2) Calibration gases may be relabeled and used after their expiration date as follows: (i) Alcohol/carbonyl calibration gases used to determine response factors according to subpart I of this part may be relabeled as specified in subpart I of this part. (ii) Other gases may be relabeled and used after the expiration date only if we approve it in advance. (c) Transfer gases from their source to analyzers using components that are dedicated to controlling and transferring only those gases. For example, do not use a regulator, valve, or transfer line for zero gas if those components were previously used to transfer a different gas mixture. We recommend that you label regulators, valves, and transfer lines to prevent contamination. Note that even small traces of a gas mixture in the dead volume of a regulator, valve, or transfer line can diffuse upstream into a high-pressure volume of gas, which would contaminate the entire high-pressure gas source, such as a compressed-gas cylinder. (d) To maintain stability and purity of gas standards, use good engineering judgment and follow the gas standard supplier's recommendations for storing and handling zero, span, and calibration gases. For example, it may be necessary to store bottles of condensable gases in a heated environment. [70 FR 40516, July 13, 2005, as amended at 73 FR 37343, June 30, 2008; 74 FR 56518, Oct. 30, 2009; 75 FR 68465, Nov. 8, 2010; 76 FR 57467, Sept. 15, 2011; 79 FR 23811, Apr. 28, 2014; 81 FR 74191, Oct. 25, 2016; 86 FR 34574, June 29, 2021; 89 FR 29823, Apr. 22, 2024; 89 FR 51238, June 17, 2024] § 1065.790 Mass standards. (a) PM balance calibration weights. (b) Dynamometer, fuel mass scale, and DEF mass scale calibration weights. [88 FR 4687, Jan. 24, 2023] Subpart I—Testing With Oxygenated Fuels § 1065.801 Applicability. (a) This subpart applies for testing with oxygenated fuels. Unless the standard-setting part specifies otherwise, the requirements of this subpart do not apply for fuels that contain less than 25% oxygenated compounds by volume. For example, you generally do not need to follow the requirements of this subpart for tests performed using a fuel containing 10% ethanol and 90% gasoline, but you must follow these requirements for tests performed using a fuel containing 85% ethanol and 15% gasoline. (b) Section 1065.805 applies for all other testing that requires measurement of any alcohols or carbonyls. (c) This subpart specifies sampling procedures and calculations that are different than those used for non-oxygenated fuels. All other test procedures of this part 1065 apply for testing with oxygenated fuels. § 1065.805 Sampling system. (a) Dilute engine exhaust, and use batch sampling to collect proportional flow-weighted dilute samples of the applicable alcohols and carbonyls. You may not use raw sampling for alcohols and carbonyls. (b) You may collect background samples for correcting dilution air for background concentrations of alcohols and carbonyls. (c) Maintain sample temperatures within the dilution tunnel, probes, and sample lines high enough to prevent aqueous condensation up to the point where a sample is collected to prevent loss of the alcohols and carbonyls by dissolution in condensed water. Use good engineering judgment to ensure that surface reactions of alcohols and carbonyls do not occur, as surface decomposition of methanol has been shown to occur at temperatures greater than 120 °C in exhaust from methanol-fueled engines. (d) You may bubble a sample of the exhaust through water to collect alcohols for later analysis. You may also use a photoacoustic analyzer to quantify ethanol and methanol in an exhaust sample as described in § 1065.269. (e) Sample the exhaust through cartridges impregnated with 2,4-dinitrophenylhydrazine to collect carbonyls for later analysis. If the standard-setting part specifies a duty cycle that has multiple test intervals (such as multiple engine starts or an engine-off soak phase), you may proportionally collect a single carbonyl sample for the entire duty cycle. For example, if the standard-setting part specifies a six-to-one weighting of hot-start to cold-start emissions, you may collect a single carbonyl sample for the entire duty cycle by using a hot-start sample flow rate that is six times the cold-start sample flow rate. (f) You may sample alcohols or carbonyls using “California Non-Methane Organic Gas Test Procedures” (incorporated by reference, see § 1065.1010). If you use this method, follow its calculations to determine the mass of the alcohol/carbonyl in the exhaust sample, but follow subpart G of this part for all other calculations (40 CFR part 1066, subpart G, for vehicle testing). (g) Use good engineering judgment to sample other oxygenated hydrocarbon compounds in the exhaust. [70 FR 40516, July 13, 2005, as amended at 73 FR 37343, June 30, 2008; 79 FR 23812, Apr. 28, 2014; 89 FR 29826, Apr. 22, 2024] § 1065.845 Response factor determination. Since FID analyzers generally have an incomplete response to alcohols and carbonyls, determine each FID analyzer's alcohol/carbonyl response factor ( RF OHCi[THC-FID] (a) You may generate response factors as described in paragraph (b) of this section, or you may use the following default response factors, consistent with good engineering judgment: Table 1 of § 1065.845—Default Values for THC FID Response Factor Relative to Propane on a C 1 Compound Response RF acetaldehyde 0.50 ethanol 0.75 formaldehyde 0.00 methanol 0.63 propanol 0.85 (b) Determine the alcohol/carbonyl response factors as follows: (1) Select a C 3 8 2 3 8 (2) Select or prepare an alcohol/carbonyl calibration gas that meets the specifications of § 1065.750 and has a concentration typical of the peak concentration expected at the hydrocarbon standard. Record the calibration concentration of the gas. (3) Start and operate the FID analyzer according to the manufacturer's instructions. (4) Confirm that the FID analyzer has been calibrated using C 3 8 1 3 8 (5) Zero the FID. Note that FID zero and span balance gases may be any combination of purified air or purified nitrogen that meets the specifications of § 1065.750. We recommend FID analyzer zero and span gases that contain approximately the flow-weighted mean concentration of O 2 (6) Span the FID with the C 3 8 (7) Introduce at the inlet of the FID analyzer the alcohol/carbonyl calibration gas that you selected under paragraph (a)(2) of this section. (8) Allow time for the analyzer response to stabilize. Stabilization time may include time to purge the analyzer and to account for its response. (9) While the analyzer measures the alcohol/carbonyl concentration, record 30 seconds of sampled data. Calculate the arithmetic mean of these values. (10) Divide the mean measured concentration by the recorded span concentration of the alcohol/carbonyl calibration gas on a C 1 RF OHCi[THC-FID] 1 (c) Alcohol/carbonyl calibration gases must remain within ±2% of the labeled concentration. You must demonstrate the stability based on a quarterly measurement procedure with a precision of ±2% percent or another method that we approve. Your measurement procedure may incorporate multiple measurements. If the true concentration of the gas changes deviates by more than ±2%, but less than ±10%, the gas may be relabeled with the new concentration. [79 FR 23812, Apr. 28, 2014, as amended at 79 FR 36658, June 30, 2014] § 1065.850 Calculations. Use the calculations specified in § 1065.665 to determine THCE or NMHCE and the calculations specified in 40 CFR 1066.635 to determine NMOG. [79 FR 23813, Apr. 28, 2014] Subpart J—Field Testing and Portable Emission Measurement Systems § 1065.901 Applicability. (a) Field testing. (b) Laboratory testing. (1) Follow the laboratory test procedures specified in this part 1065, according to § 1065.905(e). (2) Do not apply any PEMS-related field-testing adjustments or measurement allowances to laboratory emission results or standards. (3) Do not use PEMS for laboratory measurements if it prevents you from demonstrating compliance with the applicable standards in this chapter. Some of the PEMS requirements in this part 1065 are less stringent than the corresponding laboratory requirements. Depending on actual PEMS performance, you might therefore need to account for some additional measurement uncertainty when using PEMS for laboratory testing. If we ask, you must show us by engineering analysis that any additional measurement uncertainty due to your use of PEMS for laboratory testing is offset by the extent to which your engine's emissions are below the applicable standards in this chapter. For example, you might show that PEMS versus laboratory uncertainty represents 5% of the standard, but your engine's deteriorated emissions are at least 20% below the standard for each pollutant. [70 FR 40516, July 13, 2005, as amended at 73 FR 37344, June 30, 2008; 88 FR 4687, Jan. 24, 2023] § 1065.905 General provisions. (a) General. (b) Field-testing scope. (c) Field testing and the standard-setting part. (1) How many engines must I test in the field? (2) How many times must I repeat a field test on an individual engine? (3) How do I select vehicles for field testing? (4) What maintenance steps may I take before or between tests? (5) What data are needed for a single field test on an individual engine? (6) What are the limits on ambient conditions for field testing? Note that the ambient condition limits in § 1065.520 do not apply for field testing. Field testing may occur at any ambient temperature, pressure, and humidity unless otherwise specified in the standard-setting part. (7) Which exhaust constituents do I need to measure? (8) How do I account for crankcase emissions? (9) Which engine and ambient parameters do I need to measure? (10) How do I process the data recorded during field testing to determine if my engine meets field-testing standards? How do I determine individual test intervals? Note that “test interval” is defined in subpart K of this part 1065. (11) Should I warm up the test engine before measuring emissions, or do I need to measure cold-start emissions during a warm-up segment of in-use operation? (12) Do any unique specifications apply for test fuels? (13) Do any special conditions invalidate parts of a field test or all of a field test? (14) Does any special measurement allowance apply to field-test emission results or standards, based on using PEMS for field-testing versus using laboratory equipment and instruments for laboratory testing? (15) Do results of initial field testing trigger any requirement for additional field testing or laboratory testing? (16) How do I report field-testing results? (d) Field testing and this part 1065. (1) Use the applicability and general provisions of subpart A of this part. (2) Use equipment specifications in § 1065.101 and in the sections from § 1065.140 to the end of subpart B of this part, with the exception of §§ 1065.140(e)(1) and (4), 1065.170(c)(1)(vi), and 1065.195(c). Section 1065.910 identifies additional equipment that is specific to field testing. (i) For PM samples, configure dilution systems as follows: (A) Use good engineering judgment to control dilution air temperature. If you choose to directly and actively control dilution air temperature, set the temperature to 25 °C. (B) Control sample temperature to a (32 to 62) °C tolerance, as measured anywhere within 20 cm upstream or downstream of the PM storage media (such as a filter or oscillating crystal), where the tolerance applies only during sampling. (C) Maintain filter face velocity to a (5 to 100) cm/s tolerance for flow-through media. Compliance with this provision can be verified by engineering analysis. This provision does not apply for non-flow-through media. (ii) For inertial PM balances, there is no requirement to control the stabilization environment temperature or dewpoint. (3) Use measurement instruments in subpart C of this part, except as specified in § 1065.915. (4) Use calibrations and verifications in subpart D of this part, except as specified in § 1065.920. Section 1065.920 also specifies additional calibrations and verifications for field testing. (5) Use the provisions of the standard-setting part for selecting and maintaining engines in the field instead of the specifications in subpart E of this part. (6) Use the procedures in §§ 1065.930 and 1065.935 to start and run a field test. If you use a gravimetric balance for PM, weigh PM samples according to §§ 1065.590 and 1065.595. (7) Use the calculations in subpart G of this part to calculate emissions over each test interval. Note that “test interval” is defined in subpart K of this part 1065, and that the standard setting part indicates how to determine test intervals for your engine. Section 1065.940 specifies additional calculations for field testing. Use any calculations specified in the standard-setting part to determine if your engines meet the field-testing standards. The standard-setting part may also contain additional calculations that determine when further field testing is required. (8) Use a typical in-use fuel meeting the specifications of § 1065.701(d). (9) Use the lubricant and coolant specifications in §§ 1065.740 and 1065.745. (10) Use the analytical gases and other calibration standards in § 1065.750 and § 1065.790. (11) If you are testing with oxygenated fuels, use the procedures specified for testing with oxygenated fuels in subpart I of this part. (12) Apply the definitions and reference materials in subpart K of this part. (e) Laboratory testing using PEMS. (1) Use the applicability and general provisions of subpart A of this part. (2) Use equipment specifications in subpart B of this part. Section 1065.910 specifies additional equipment specific to testing with PEMS. (3) Use measurement instruments in subpart C of this part, except as specified in § 1065.915. (4) Use calibrations and verifications in subpart D of this part, except as specified in § 1065.920. Section 1065.920 also specifies additional calibration and verifications for PEMS. (5) Use the provisions of § 1065.401 for selecting engines for testing. Use the provisions of subpart E of this part for maintaining engines, except as specified in the standard-setting part. (6) Use the procedures in subpart F of this part and in the standard-setting part to start and run a laboratory test. (7) Use the calculations in subpart G of this part to calculate emissions over the applicable duty cycle. Section 1065.940 specifies additional calculations for testing with PEMS. (8) Use a fuel meeting the specifications of subpart H of this part, as specified in the standard-setting part. (9) Use the lubricant and coolant specifications in §§ 1065.740 and 1065.745. (10) Use the analytical gases and other calibration standards in §§ 1065.750 and 1065.790. (11) If you are testing with oxygenated fuels, use the procedures specified for testing with oxygenated fuels in subpart I of this part. (12) Apply the definitions and reference materials in subpart K of this part. (f) Summary Table 1 of § 1065.905—Summary of Testing Requirements Specified Outside of This Subpart Subpart Applicability for field testing a Applicability for laboratory a Applicability for laboratory a A: Applicability and general provisions Use all Use all Use all. B: Equipment for testing Use §§ 1065.101 and 1065.140 through the end of subpart B of this part, except §§ 1065.140(e)(1) and (4), 1065.170(c)(1)(vi), and 1065.195(c). Section 1065.910 specifies equipment specific to field testing Use all Use all. Section 1065.910 specifies equipment specific to laboratory testing with PEMS. C: Measurement instruments Use all Section 1065.915 allows deviations. Use all except § 1065.295(c) Use all except § 1065.295(c). D: Calibrations and verifications Use all except §§ 1065.308 and 1065.309. Section 1065.920 allows deviations, but also has additional specifications Use all Use all. Section 1065.920 allows deviations, but also has additional specifications. E: Test engine selection, maintenance, and durability Do not use Use standard-setting part. Use all Use all. F: Running an emission test in the laboratory Use §§ 1065.590 and 1065.595 for PM. §§ 1065.930 and 1065.935 to start and run a field test Use all Use all. G: Calculations and data requirements Use all Section 1065.940 has additional calculation instructions Use all Use all. Section 1065.940 has additional calculation instructions H: Fuels, engine fluids, analytical gases, and other calibration materials Use all Use all Use all. I: Testing with oxygenated fuels Use all Use all Use all. K: Definitions and reference materials Use all Use all Use all. a [70 FR 40516, July 13, 2005, as amended at 73 FR 37344, June 30, 2008; 75 FR 68465, Nov. 8, 2010; 79 FR 23813, Apr. 28, 2014; 86 FR 34574, June 29, 2021] § 1065.910 PEMS auxiliary equipment for field testing. For field testing you may use various types of auxiliary equipment to attach PEMS to a vehicle or engine and to power PEMS. (a) When you use PEMS, you may route engine intake air or exhaust through a flow meter. Route the engine intake air or exhaust as follows: (1) Flexible connections. (i) You may use flexible connectors to enlarge or reduce the pipe diameters to match that of your test equipment. (ii) We recommend that you use flexible connectors that do not exceed a length of three times their largest inside diameter. (iii) We recommend that you use four-ply silicone-fiberglass fabric with a temperature rating of at least 315 °C for flexible connectors. You may use connectors with a spring-steel wire helix for support and you may use Nomex TM (iv) Use stainless-steel hose clamps to seal flexible connectors, or use clamps that seal equivalently. (v) You may use additional flexible connectors to connect to flow meters. (2) Tubing (3) Flow restriction. (b) Locate the PEMS to minimize the effects of the following parameters or place the PEMS in an environmental enclosure that minimizes the effect of these parameters on the emission measurement: (1) Ambient temperature changes. (2) Electromagnetic radiation. (3) Mechanical shock and vibration. (c) Use mounting hardware as required for securing flexible connectors, ambient sensors, and other equipment. Use structurally sound mounting points such as vehicle frames, trailer hitch receivers, walk spaces, and payload tie-down fittings. We recommend mounting hardware such as clamps, suction cups, and magnets that are specifically designed for your application. We also recommend considering mounting hardware such as commercially available bicycle racks, trailer hitches, and luggage racks where applicable. (d) Field testing may require portable electrical power to run your test equipment. Power your equipment, as follows: (1) You may use electrical power from the vehicle, equipment, or vessel, up to the highest power level, such that all the following are true: (i) The power system is capable of safely supplying power, such that the power demand for testing does not overload the power system. (ii) The engine emissions do not change significantly as a result of the power demand for testing. (iii) The power demand for testing does not increase output from the engine by more than 1% of its maximum power. (2) You may install your own portable power supply. For example, you may use batteries, fuel cells, a portable generator, or any other power supply to supplement or replace your use of vehicle power. You may connect an external power source directly to the vehicle's, vessel's, or equipment's power system; however, you must not supply power to the vehicle's power system in excess of 1% of the engine's maximum power. [73 FR 37344, June 30, 2008, as amended at 75 FR 23058, Apr. 30, 2010; 86 FR 34575, June 29, 2021; 88 FR 4688, Jan. 24, 2023] § 1065.915 PEMS instruments. (a) Instrument specifications Table 1 of § 1065.915—Recommended Minimum PEMS Measurement Instrument Performance Measurement Measured quantity Rise time, t 10-90 t 90-10 Recording Accuracy a Repeatability a Noise a Engine speed transducer f n 1 s 1 Hz means 5% of pt. or 1% of max 2% of pt. or 1% of max 0.5% of max. Engine torque estimator, BSFC (This is a signal from an engine's ECM) T 1 s 1 Hz means 8% of pt. or 5% of max 2% of pt. or 1% of max 1% of max. General pressure transducer (not a part of another instrument) p 5 s 1 Hz 5% of pt. or 5% of max 2% of pt. or 0.5% of max 1% of max. Atmospheric pressure meter p atmos 50 s 0.1 Hz 250 Pa 200 Pa 100 Pa. General temperature sensor (not a part of another instrument) T 5 s 1 Hz 1% of pt. K or 5 K 0.5% of pt. K or 2 K 0.5% of max 0.5 K. General dewpoint sensor T dew 50 s 0.1 Hz 3 K 1 K 1 K. Exhaust flow meter n 1 s 1 Hz means 5% of pt. or 3% of max 2% of pt 2% of max. Dilution air, inlet air, exhaust, and sample flow meters n 1 s 1 Hz means 2.5% of pt. or 1.5% of max 1.25% of pt. or 0.75% of max 1% of max. Continuous gas analyzer x 5 s 1 Hz 4% of pt. or 4% of meas 2% of pt. or 2% of meas 1% of max. Gravimetric PM balance m PM See § 1065.790 0.5 µg Inertial PM balance m PM 4% of pt. or 4% of meas 2% of pt. or 2% of meas 1% of max. a (b) Redundant measurements. (c) Field-testing ambient effects on PEMS. (d) ECM signals. (1) Recording ECM signals. (i) If your ECM updates a broadcast signal more frequently than 1 Hz, use PEMS to sample and record the signal's value more frequently. Calculate and record the 1 Hz mean of the more frequently updated data. (ii) If your ECM updates a broadcast signal less frequently than 1 Hz, use PEMS to sample and record the signal's value at the most frequent rate. Linearly interpolate between recorded values and record the interpolated values at 1 Hz. (iii) Optionally, you may use PEMS to electronically filter the ECM signals to meet the rise time and fall time specifications in Table 1 of this section. Record the filtered signal at 1 Hz. (2) Omitting ECM signals. (3) Aligning ECM signals with other data. (4) ECM signals for determining test intervals. (5) ECM signals for determining brake-specific emissions. (i) Speed. (ii) Torque. (A) ECM torque. (B) ECM %-load. (C) Your algorithms. (iii) BSFC. (A) Use ECM engine speed and ECM fuel flow signals to interpolate brake-specific fuel consumption data, which might be available from an engine laboratory as a function of ECM engine speed and ECM fuel signals. (B) Use a single BSFC value that approximates the BSFC value over a test interval (as defined in subpart K of this part). This value may be a nominal BSFC value for all engine operation determined over one or more laboratory duty cycles, or it may be any other BSFC that you determine. If you use a nominal BSFC, we recommend that you select a value based on the BSFC measured over laboratory duty cycles that best represent the range of engine operation that defines a test interval for field-testing. You may use the methods of this paragraph (d)(5)(iii)(B) only if it does not adversely affect your ability to demonstrate compliance with applicable standards. (C) You may develop and use your own combination of ECM signals to determine BSFC. (iv) ECM fuel rate. (v) Other ECM signals. (6) Permissible deviations. [70 FR 40516, July 13, 2005, as amended at 73 FR 37344, June 30, 2008; 73 FR 59342, Oct. 8, 2008; 75 FR 68466, Nov. 8, 2010; 76 FR 57467, Sept. 15, 2011; 79 FR 23813, Apr. 28, 2014; 86 FR 34575, June 29, 2021; 88 FR 4688, Jan. 24, 2023] § 1065.920 PEMS calibrations and verifications. (a) Subsystem calibrations and verifications. (b) Overall verification. (1) Mount an engine on a dynamometer for laboratory testing. Prepare the laboratory and PEMS for emission testing, as described in this part, to get simultaneous measurements. We recommend selecting an engine with emission levels close to the applicable duty-cycle standards, if possible. (2) Select or create a duty cycle that has all the following characteristics: (i) Engine operation that represents normal in-use speeds, loads, and degree of transient activity. Consider using data from previous field tests to generate a cycle. (ii) A duration of (6 to 9) hours. (3) Starting with a warmed-up engine, run a valid emission test with the duty cycle from paragraph (b)(2) of this section. The laboratory and PEMS must both meet applicable validation requirements, such as drift validation, hydrocarbon contamination validation, and proportional validation. (4) Determine the brake-specific emissions and mass rate emissions, as applicable, for each test interval for both laboratory and the PEMS measurements, as follows: (i) For both laboratory and PEMS measurements, use identical values to determine the beginning and end of each test interval. (ii) For both laboratory and PEMS measurements, use identical values to determine total work over each test interval. (iii) If the standard-setting part specifies the use of a measurement allowance for field testing, also apply the measurement allowance during calibration using good engineering judgment. If the measurement allowance is normally added to the standard, this means you must subtract the measurement allowance from measured PEMS emission results. (iv) Round results to the same number of significant digits as the standard. (5) For each test interval and emission, subtract the lab result from the PEMS result. (6) The PEMS passes the verification of this paragraph (b) if any one of the following are true for each constituent: (i) 91% or more of the differences are zero or less than zero. (ii) The entire set of test-interval results passes the 95% confidence alternate-procedure statistics for field testing ( t F [70 FR 40516, July 13, 2005, as amended at 73 FR 37345, June 30, 2008; 75 FR 68467, Nov. 8, 2010; 79 FR 23814, Apr. 28, 2014; 88 FR 4688, Jan. 24, 2023] § 1065.925 PEMS preparation for field testing. Take the following steps to prepare PEMS for field testing: (a) Verify that ambient conditions at the start of the test are within the limits specified in the standard-setting part. Continue to monitor these values to determine if ambient conditions exceed the limits during the test. (b) Install a PEMS and any accessories needed to conduct a field test. (c) Power the PEMS and allow pressures, temperatures, and flows to stabilize to their operating set points. (d) Bypass or purge any gaseous sampling PEMS instruments with ambient air until sampling begins to prevent system contamination from excessive cold-start emissions. (e) Conduct calibrations and verifications. (f) Operate any PEMS dilution systems at their expected flow rates using a bypass. (g) If you use a gravimetric balance to determine whether an engine meets an applicable PM standard, follow the procedures for PM sample preconditioning and tare weighing as described in § 1065.590. Operate the PM-sampling system at its expected flow rates using a bypass. (h) Verify the amount of contamination in the PEMS HC sampling system before the start of the field test as follows: (1) Select the HC analyzer range for measuring the maximum concentration expected at the HC standard. (2) Zero the HC analyzers using a zero gas or ambient air introduced at the analyzer port. When zeroing a FID, use the FID's burner air that would be used for in-use measurements (generally either ambient air or a portable source of burner air). (3) Span the HC analyzer using span gas introduced at the analyzer port. (4) Overflow zero or ambient air at the HC probe inlet or into a tee near the probe outlet. (5) Measure the HC concentration in the sampling system: (i) For continuous sampling, record the mean HC concentration as overflow zero air flows. (ii) For batch sampling, fill the sample medium and record its mean concentration. (6) Record this value as the initial HC concentration, x THCinit (7) If the initial HC concentration exceeds the greater of the following values, determine the source of the contamination and take corrective action, such as purging the system or replacing contaminated portions: (i) 2% of the flow-weighted mean concentration expected at the standard or measured during testing. (ii) 2 µmol/mol. (8) If corrective action does not resolve the deficiency, you may use a contaminated HC system if it does not prevent you from demonstrating compliance with the applicable emission standards. [70 FR 40516, July 13, 2005, as amended at 73 FR 37345, June 30, 2008; 73 FR 59342, Oct. 8, 2008; 75 FR 68467, Nov. 8, 2010; 76 FR 57467, Sept. 15, 2011] § 1065.930 Engine starting, restarting, and shutdown. Unless the standard-setting part specifies otherwise, start, restart, and shut down the test engine for field testing as follows: (a) Start or restart the engine as described in the owners manual. (b) If the engine does not start after 15 seconds of cranking, stop cranking and determine the reason it failed to start. However, you may crank the engine longer than 15 seconds, as long as the owners manual or the service-repair manual describes the longer cranking time as normal. (c) Respond to engine stalling with the following steps: (1) If the engine stalls during a required warm-up before emission sampling begins, restart the engine and continue warm-up. (2) If the engine stalls at any other time after emission sampling begins, restart the engine and continue testing. (d) Shut down and restart the engine according to the manufacturer's specifications, as needed during normal operation in-use, but continue emission sampling until the field test is complete. § 1065.935 Emission test sequence for field testing. (a) Time the start of field testing as follows: (1) If the standard-setting part requires only hot-stabilized emission measurements, operate the engine in-use until the engine coolant, block, or head absolute temperature is within ±10% of its mean value for the previous 2 min or until an engine thermostat controls engine temperature with coolant or air flow. (2) If the standard-setting part requires hot-start emission measurements, shut down the engine after at least 2 min at the temperature tolerance specified in paragraph (a)(1) of this section. Start the field test within 20 min of engine shutdown. (3) If the standard-setting part requires cold-start emission measurements, proceed to the steps specified in paragraph (b) of this section. (b) Take the following steps before emission sampling begins: (1) For batch sampling, connect clean storage media, such as evacuated bags or tare-weighed PM sample media. (2) Operate the PEMS according to the instrument manufacturer's instructions and using good engineering judgment. (3) Operate PEMS heaters, dilution systems, sample pumps, cooling fans, and the data-collection system. (4) Pre-heat or pre-cool PEMS heat exchangers in the sampling system to within their tolerances for operating temperatures. (5) Allow all other PEMS components such as sample lines, filters, and pumps to stabilize at operating temperature. (6) Verify that no significant vacuum-side leak exists in the PEMS, as described in § 1065.345. (7) Adjust PEMS flow rates to desired levels, using bypass flow if applicable. (8) Zero and span all PEMS gas analyzers using NIST-traceable gases that meet the specifications of § 1065.750. (c) Start testing as follows: (1) Before the start of the first test interval, zero or re-zero any PEMS electronic integrating devices, as needed. (2) If the engine is already running and warmed up and starting is not part of field testing, start the field test by simultaneously starting to sample exhaust, record engine and ambient data, and integrate measured values using a PEMS. (3) If engine starting is part of field testing, start field testing by simultaneously starting to sample from the exhaust system, record engine and ambient data, and integrate measured values using a PEMS. Then start the engine. (d) Continue the test as follows: (1) Continue to sample exhaust, record data and integrate measured values throughout normal in-use operation of the engine. (2) Between each test interval, zero or re-zero any electronic integrating devices, and reset batch storage media, as needed. (3) The engine may be stopped and started, but continue to sample emissions throughout the entire field test. (4) Conduct periodic verifications such as zero and span verifications on PEMS gas analyzers and use these to correct for drift according to paragraph (g) of this section. Do not include data recorded during verifications in emission calculations. Conduct the verifications as follows: (i) For PEMS gas analyzers used to determine NTE emission values, perform verifications as recommended by the PEMS manufacturer or as indicated by good engineering judgment. (ii) For PEMS gas analyzers used to determine bin emission values, perform zero verifications at least hourly using purified air. Perform span verification at the end of the shift-day or more frequently as recommended by the PEMS manufacturer or as indicated by good engineering judgment. (5) You may periodically condition and analyze batch samples in-situ, including PM samples; for example you may condition an inertial PM balance substrate if you use an inertial balance to measure PM. (6) You may have personnel monitoring and adjusting the PEMS during a test, or you may operate the PEMS unattended. (e) Stop testing as follows: (1) Continue sampling as needed to get an appropriate amount of emission measurement, according to the standard setting part. If the standard-setting part does not describe when to stop sampling, develop a written protocol before you start testing to establish how you will stop sampling. You may not determine when to stop testing based on emission results. (2) At the end of the field test, allow the sampling systems' response times to elapse and then stop sampling. Stop any integrators and indicate the end of the test cycle on the data-collection medium. (3) You may shut down the engine before or after you stop sampling. (f) For any proportional batch sample, such as a bag sample or PM sample, verify for each test interval whether or not proportional sampling was maintained according to § 1065.545. Void the sample for any test interval that did not maintain proportional sampling according to § 1065.545. (g) Take the following steps after emission sampling is complete: (1) As soon as practical after emission sampling, analyze any gaseous batch samples. (2) If you used dilution air, either analyze background samples or assume that background emissions were zero. Refer to § 1065.140 for dilution-air specifications. (3) After quantifying all exhaust gases, record mean analyzer values after stabilizing a zero gas to each analyzer, then record mean analyzer values after stabilizing the span gas to the analyzer. Stabilization may include time to purge an analyzer of any sample gas and any additional time to account for analyzer response. Use these recorded values, including pre-test verifications and any zero verifications during testing, to correct for drift as described in § 1065.550. (4) Verify PEMS gas analyzers used to determine NTE emission values as follows: (i) Invalidate any data that does not meet the range criteria in § 1065.550. Note that it is acceptable that analyzers exceed 100% of their ranges when measuring emissions between test intervals, but not during test intervals. You do not have to retest an engine if the range criteria are not met. (ii) Invalidate any data that does not meet the drift criterion in § 1065.550. For HC, invalidate any data if the difference between the uncorrected and the corrected brake-specific HC emission values are not within ±10% of the uncorrected results or the applicable standard, whichever is greater. For data that does meet the drift criterion, correct those test intervals for drift according to § 1065.672 and use the drift corrected results in emissions calculations. (5) Verify PEMS gas analyzers used to determine bin emission values as follows: (i) Invalidate data from a whole shift-day if more than 1% of recorded 1 Hz data exceeds 100% of the selected gas analyzer range. For analyzer outputs exceeding 100% of range, calculate emission results using the reported value. You must retest an engine if the range criteria are not met. (ii) Invalidate any data for periods in which the CO and CO 2 (iii) For PEMS NO X (A) The allowable analyzer zero-drift between successive zero verifications is ±2.5 ppm. The analyzer zero-drift limit over the shift-day is ±10 ppm. (B) The allowable analyzer span-drift limit is ±4% of the measured span value between successive span verifications. (6) Unless you weighed PM in-situ, such as by using an inertial PM balance, place any used PM samples into covered or sealed containers and return them to the PM-stabilization environment and weigh them as described in § 1065.595. [70 FR 40516, July 13, 2005, as amended at 73 FR 37345, June 30, 2008; 88 FR 4688, Jan. 24, 2023; 89 FR 29826, Apr. 22, 2024] § 1065.940 Emission calculations. (a) Perform emission calculations as described in § 1065.650 to calculate brake-specific emissions for each test interval using any applicable information and instructions in the standard-setting part. (b) You may use a fixed molar mass for the diluted exhaust mixture for field testing. Determine this fixed value by engineering analysis. [75 FR 68467, Nov. 8, 2010] Subpart K—Definitions and Other Reference Information § 1065.1001 Definitions. The definitions in this section apply to this part. The definitions apply to all subparts unless we note otherwise. All undefined terms have the meaning the Act gives them. The definitions follow: 300 series stainless steel R a Accuracy Act Adjustable parameter Aerodynamic diameter Aftertreatment Allowed procedures Alternate procedures Applicable standard Aqueous condensation Atmospheric pressure Auto-ranging Auxiliary emission-control device Average Brake power C 1 1 1 3 8 1 1 Calibration Calibration gas Carbon-containing fuel Certification Compression-ignition Confidence interval Constant-speed engine Constant-speed operation Coriolis meter Dewpoint Diesel exhaust fluid (DEF) X Diesel exhaust fluid Dilution ratio (DR) Discrete-mode Dispersion (1) The broadening and lowering of a signal due to any fluid capacitance, fluid mixing, or electronic filtering in a sampling system. (Note: To adjust a signal so its dispersion matches that of another signal, you may adjust the system's fluid capacitance, fluid mixing, or electronic filtering.) (2) The mixing of a fluid, especially as a result of fluid mechanical forces or chemical diffusion. Drift means the difference between a zero or calibration signal and the respective value reported by a measurement instrument immediately after it was used in an emission test, as long as you zeroed and spanned the instrument just before the test. Dual-fuel Duty cycle (1) A series of speed and torque values (or power values) that an engine must follow during a laboratory test. Duty cycles are specified in the standard-setting part. A single duty cycle may consist of one or more test intervals. A series of speed and torque values meeting the definition of this paragraph (1) may also be considered a test cycle. For example, a duty cycle may be a ramped-modal cycle, which has one test interval; a cold-start plus hot-start transient cycle, which has two test intervals; or a discrete-mode cycle, which has one test interval for each mode. (2) A set of weighting factors and the corresponding speed and torque values, where the weighting factors are used to combine the results of multiple test intervals into a composite result. Electric power generation application Electronic control module Emission-control system Emission-data engine Emission-related maintenance Engine family Engine governed speed Enhanced-idle EPA Program Officer Exhaust-gas recirculation Fall time, t 90-10 (1) The point at which the response has fallen 10% of the total amount it will fall in response to the step change. (2) The point at which the response has fallen 90% of the total amount it will fall in response to the step change. Flexible-fuel Flow-weighted mean Fuel type Good engineering judgment HEPA filter High-idle speed High-speed governor Hydraulic diameter Hydrocarbon (HC) Identification number Idle speed Intermediate speed Lean-burn engine Linearity a 0, a 1, r 2 SEE, Manufacturer Maximum test speed Maximum test torque Measurement allowance Mode (1) A distinct combination of engine speed and load for steady-state testing. (2) A continuous combination of speeds and loads specifying a transition during a ramped-modal test. (3) A distinct operator demand setting, such as would occur when testing locomotives or constant-speed engines. Neat NIST-accepted NIST-traceable Noise No-load Nonmethane hydrocarbon equivalent (NMHCE) Nonmethane hydrocarbons (NMHC) Nonmethane nonethane hydrocarbon (NMNEHC) Nonroad Nonroad engine Open crankcase emissions Operator demand P f n T. Oxides of nitrogen means NO and NO 2 2 2 Oxygenated fuels Partial pressure p x Percent Portable emission measurement system (PEMS) Precision noise repeatability Procedures Proving ring PTFE TM Purified air Ramped-modal Recommend Rechargeable Energy Storage System (RESS) Regression statistics Repeatability Revoke Rise time, t 10-90 (1) The point at which the response has risen 10% of the total amount it will rise in response to the step change. (2) The point at which the response has risen 90% of the total amount it will rise in response to the step change. Roughness (or average roughness, R a ) Round Scheduled maintenance Shared atmospheric pressure meter Shared humidity measurement Span Span gas Spark-ignition Special procedures Specified procedures Standard deviation Standard-setting part Steady-state Stoichiometric Storage medium t 0−50 (1) The point at which the step change is initiated at the sample probe. (2) The point at which the response has risen 50% of the total amount it will rise in response to the step change. t 100−50 (1) The point at which the step change is initiated at the sample probe. (2) The point at which the response has fallen 50% of the total amount it will fall in response to the step change. Test engine Test interval Test sample Tolerance Total hydrocarbon (THC) Total hydrocarbon equivalent (THCE) Transformation time t 50 t 0−50 t 100−50 Uncertainty United States Useful life Variable-speed engine Vehicle Verification We (us, our) Work Zero Zero gas zero gas [70 FR 40516, July 13, 2005, as amended at 73 FR 37346, June 30, 2008; 73 FR 59342, Oct. 8, 2008; 74 FR 8428, Feb. 24, 2009; 74 FR 56518, Oct. 30, 2009; 75 FR 23058, Apr. 30, 2010; 76 FR 57467, Sept. 15, 2011; 79 FR 23814, Apr. 28, 2014; 81 FR 74191, Oct. 25, 2016; 86 FR 34575, June 29, 2021; 88 FR 4689, Jan. 24, 2023; 89 FR 29826, Apr. 22, 2024] § 1065.1005 Symbols, abbreviations, acronyms, and units of measure. The procedures in this part generally follow the International System of Units (SI), as detailed in NIST Special Publication 811, which we incorporate by reference in § 1065.1010. See § 1065.20 for specific provisions related to these conventions. This section summarizes the way we use symbols, units of measure, and other abbreviations. (a) Symbols for quantities. Table 1 of § 1065.1005—Symbols for Quantities Symbol Quantity Unit Unit symbol Units in terms of SI base units α atomic hydrogen-to-carbon ratio mole per mole mol/mol 1. A area square meter m 2 m 2 a 0 intercept of least squares regression a 1 slope of least squares regression a g acceleration of Earth's gravity meter per square second m/s 2 m· s − 2 β ratio of diameters meter per meter m/m 1. β atomic oxygen-to-carbon ratio mole per mole mol/mol 1. C # number of carbon atoms in a molecule c power-specific carbon mass error coefficient gram per kilowatt-hour g/(kW·hr) 3.6 − 1 − 9 − 2 2 C d discharge coefficient C f flow coefficient δ atomic nitrogen-to-carbon ratio mole per mole mol/mol 1. d diameter meter m m. d power-specific carbon mass rate absolute error coefficent gram per kilowatt-hour g/(kW·hr) 3.6 − 1 − 9 − 2 2 DR dilution ratio mole per mole mol/mol 1. ε error between a quantity and its reference ∈ difference or error quantity e brake-specific emission or fuel consumption gram per kilowatt hour g/(kW·hr) 3.6 − 1 − 9 − 2 2 F F-test statistic ƒ frequency hertz Hz s − 1 ƒ n angular speed (shaft) revolutions per minute r/min π · 30 − 1 − 1 γ ratio of specific heats (joule per kilogram kelvin) per (joule per kilogram kelvin) (J/(kg·K))/(J/(kg·K)) 1. γ atomic sulfur-to-carbon ratio mole per mole mol/mol 1. κ opacity K correction factor 1. K v calibration coefficient m 4 0.5 m 4 − 1 0.5 l length meter m m. L limit µ viscosity, dynamic pascal second Pa·s m − 1 − 1 M molar mass 1 gram per mole g/mol 10 − 3 − 1 m mass kilogram kg kg. m mass rate kilogram per second kg/s kg · s − 1 v viscosity, kinematic meter squared per second m 2 m 2 − 1 N total number in series n amount of substance mole mol mol. n amount of substance rate mole per second mol/s mol · s − 1 P power kilowatt kW 10 3 2 − 3 PF penetration fraction p pressure pascal Pa m − 1 − 2 ρ mass density kilogram per cubic meter kg/m 3 m − 3 Δ p differential static pressure pascal Pa m − 1 − 2 r ratio of pressures pascal per pascal Pa/Pa 1. r coefficient of determination Ra average surface roughness micrometer µm 10 − 6 Re # Reynolds number RF response factor RH relative humidity σ non-biased standard deviation S Sutherland constant kelvin K K. SEE standard error of the estimate T absolute temperature kelvin K K. T Celsius temperature degree Celsius °C K−273.15. T torque (moment of force) newton meter N·m m 2 − 2 θ plane angle degrees ° rad. t time second s s. Δ t time interval, period, 1/frequency second s s. V volume cubic meter m 3 m 3 V volume rate cubic meter per second m 3 m 3 − 1 W work kilowatt-hour kW·hr 3.6 · 10 6 2 − 2 w C carbon mass fraction gram per gram g/g 1. x amount of substance mole fraction. 2 mole per mole mol/mol 1. X flow-weighted mean concentration mole per mole mol/mol 1. y generic variable Z compressibility factor 1 X 2 1 (b) Symbols for chemical species. Table 2 of § 1065.1005—Symbols for Chemical Species and Exhaust Constituents Symbol Species Ar argon. C carbon. CH 2 formaldehyde. CH 2 2 formic acid. CH 3 methanol. CH 4 methane. C 2 4 acetaldehyde. C 2 5 ethanol. C 2 6 ethane. C 3 7 propanol. C 3 8 propane. C 4 10 butane. C 5 12 pentane. CO carbon monoxide. CO 2 carbon dioxide. H atomic hydrogen. H 2 molecular hydrogen. H 2 water. H 2 4 sulfuric acid. HC hydrocarbon. He helium. 85 krypton 85. N 2 molecular nitrogen. NH 3 ammonia. NMHC nonmethane hydrocarbon. NMHCE nonmethane hydrocarbon equivalent. NMNEHC nonmethane-nonethane hydrocarbon. NO nitric oxide. NO 2 nitrogen dioxide. NO X oxides of nitrogen. N 2 nitrous oxide. NMOG nonmethane organic gases. NONMHC non-oxygenated nonmethane hydrocarbon. NOTHC non-oxygenated total hydrocarbon. O 2 molecular oxygen. OHC oxygenated hydrocarbon. 210 polonium 210. PM particulate matter. S sulfur. SVOC semi-volatile organic compound. THC total hydrocarbon. THCE total hydrocarbon equivalent. ZrO 2 zirconium dioxide. (c) Prefixes. Table 3 of § 1065.1005—Prefixes Symbol Prefix name Factor µ micro 10 − 6 m milli 10 − 3 c centi 10 − 2 k kilo 10 3 M mega 10 6 (d) Superscripts Table 4 of § 1065.1005—Superscripts Superscript Meaning overbar (such as y arithmetic mean. overdot (such as y quantity per unit time. (e) Subscripts Table 5 of § 1065.1005—Subscripts Subscript Meaning a absolute ( e.g. abs absolute quantity. act actual condition. air air, dry. amb ambient. atmos atmospheric. bkgnd background. C carbon mass. cal calibration quantity. CFV critical flow venturi. comb combined. comp composite value. cor corrected quantity. dil dilution air. dew dewpoint. dexh diluted exhaust. dry dry condition. dutycycle duty cycle. ∈ related to a difference or error quantity. exh raw exhaust. exp expected quantity. fluid fluid stream. fn feedback speed. frict friction. fuel fuel consumption. hi,idle condition at high-idle. i an individual of a series. idle condition at idle. in quantity in. init initial quantity, typically before an emission test. int intake air. j an individual of a series. mapped conditions over which an engine can operate. max the maximum ( i.e. meas measured quantity. media PM sample media. mix mixture of diluted exhaust and air. norm normalized. out quantity out. P power. part partial quantity. PDP positive-displacement pump. post after the test interval. pre before the test interval. prod stoichiometric product. r relative ( e.g. rate rate (divided by time). record record rate. ref reference quantity. rev revolution. sat saturated condition. s slip. span span quantity. SSV subsonic venturi. std standard condition. stroke engine strokes per power stroke. T torque. test test quantity. test,alt alternate test quantity. uncor uncorrected quantity. vac vacuum side of the sampling system. weight calibration weight. zero zero quantity (f) Constants. (1) This part uses the following constants for the composition of dry air: Table 6 of § 1065.1005—Constants Symbol Quantity mol/mol γ Arair amount of argon in dry air 0.00934 γ CO2air amount of carbon dioxide in dry air 0.000375 γ N2air amount of nitrogen in dry air 0.78084 γ O2air amount of oxygen in dry air 0.209445 (2) This part uses the following molar masses or effective molar masses of chemical species: Table 7 of § 1065.1005—Molar Masses Symbol Quantity g/mol -3 -1 M air molar mass of dry air 1 28.96559 M Ar molar mass of argon 39.948 M C molar mass of carbon 12.0107 M CH3OH molar mass of methanol 32.04186 M C2H5OH molar mass of ethanol 46.06844 M C2H4O molar mass of acetaldehyde 44.05256 M CH4N2O molar mass of urea 60.05526 M C2H6 molar mass of ethane 30.06904 M C3H8 molar mass of propane 44.09562 M C3H7OH molar mass of propanol 60.09502 M CO molar mass of carbon monoxide 28.0101 M CH4 molar mass of methane 16.0425 M CO2 molar mass of carbon dioxide 44.0095 M H molar mass of atomic hydrogen 1.00794 M H2 molar mass of molecular hydrogen 2.01588 M H2O molar mass of water 18.01528 M CH2O molar mass of formaldehyde 30.02598 M He molar mass of helium 4.002602 M N molar mass of atomic nitrogen 14.0067 M N2 molar mass of molecular nitrogen 28.0134 M NH3 molar mass of ammonia 17.03052 M NMHC effective C1 molar mass of nonmethane hydrocarbon 2 13.875389 M NMHCE effective C1 molar mass of nonmethane hydrocarbon equivalent 2 13.875389 M NMNEHC effective C1 molar mass of nonmethane-nonethane hydrocarbon 2 13.875389 M NOx effective molar mass of oxides of nitrogen 3 46.0055 M N2O molar mass of nitrous oxide 44.0128 M O molar mass of atomic oxygen 15.9994 M O2 molar mass of molecular oxygen 31.9988 M S molar mass of sulfur 32.065 M THC effective C 1 2 13.875389 M THCE effective C 1 2 13.875389 1 2 1 3 X 2 (3) This part uses the following molar gas constant for ideal gases: Table 8 of § 1065.1005—Molar Gas Constant for Ideal Gases Symbol Quantity J/(mol·K) 2 − 2 − 1 − 1 R molar gas constant 8.314472 (4) This part uses the following ratios of specific heats for dilution air and diluted exhaust: Table 9 of § 1065.1005—Ratios of Specific Heats for Dilution Air and Diluted Exhaust Symbol Quantity [J/(kg·K)]/[J/(kg·K)] γ air ratio of specific heats for intake air or dilution air 1.399 γ dil ratio of specific heats for diluted exhaust 1.399 γ exh ratio of specific heats for raw exhaust 1.385 (g) Other acronyms and abbreviations. Table 10 of § 1065.1005—Other Acronyms and Abbreviations Acronym Meaning ABS acrylonitrile-butadiene-styrene. ASTM ASTM International. BMD bag mini-diluter. BSFC brake-specific fuel consumption. CARB California Air Resources Board. CFR Code of Federal Regulations. CFV critical-flow venturi. CI compression-ignition. CITT Curb Idle Transmission Torque. CLD chemiluminescent detector. CVS constant-volume sampler. DEF diesel exhaust fluid. DF deterioration factor. ECM electronic control module. EFC electronic flow control. e.g. exempli gratia, for example. EGR exhaust gas recirculation. EPA Environmental Protection Agency. FEL Family Emission Limit. FID flame-ionization detector. FTIR Fourier transform infrared. GC gas chromatograph. GC-ECD gas chromatograph with an electron-capture detector. GC-FID gas chromatograph with a flame ionization detector. HEPA high-efficiency particulate air. IBP initial boiling point. IBR incorporated by reference. i.e. id est, in other words. ISO International Organization for Standardization. LPG liquefied petroleum gas. MPD magnetopneumatic detection. NDIR nondispersive infrared. NDUV nondispersive ultraviolet. NIST National Institute for Standards and Technology. NMC nonmethane cutter. PDP positive-displacement pump. PEMS portable emission measurement system. PFD partial-flow dilution. PLOT porous layer open tubular. PMD paramagnetic detection. PMP Polymethylpentene. pt. a single point at the mean value expected at the standard. psi pounds per square inch. PTFE polytetrafluoroethylene (commonly known as Teflon TM RE rounding error. RESS rechargeable energy storage system. RFPF response factor penetration fraction. RMC ramped-modal cycle. rms root-mean square. RTD resistive temperature detector. SAW surface acoustic wave. SEE standard error of the estimate. SSV subsonic venturi. SI spark-ignition. THC-FID total hydrocarbon flame ionization detector. TINV inverse student t UCL upper confidence limit. UFM ultrasonic flow meter. U.S.C. United States Code [79 FR 23815, Apr. 28, 2014, as amended at 81 FR 74191, Oct. 25, 2016; 86 FR 34575, June 29, 2021; 87 FR 64866, Oct. 26, 2022; 88 FR 4689, Jan. 24, 2023] § 1065.1010 Incorporation by reference. Certain material is incorporated by reference into this part with the approval of the Director of the Federal Register under 5 U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other than that specified in this section, EPA must publish a document in the Federal Register www.epa.gov/dockets www.archives.gov/federal-register/cfr/ibr-locations.html [email protected] (a) ASTM material http://www.astm.org: (1) ASTM D86-12, Standard Test Method for Distillation of Petroleum Products at Atmospheric Pressure, approved December 1, 2012 (“ASTM D86”), IBR approved for §§ 1065.703(b) and 1065.710(b) and (c). (2) ASTM D93-13, Standard Test Methods for Flash Point by Pensky-Martens Closed Cup Tester, approved July 15, 2013 (“ASTM D93”), IBR approved for § 1065.703(b). (3) ASTM D130-12, Standard Test Method for Corrosiveness to Copper from Petroleum Products by Copper Strip Test, approved November 1, 2012 (“ASTM D130”), IBR approved for § 1065.710(b). (4) ASTM D381-12, Standard Test Method for Gum Content in Fuels by Jet Evaporation, approved April 15, 2012 (“ASTM D381”), IBR approved for § 1065.710(b). (5) ASTM D445-12, Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity), approved April 15, 2012 (“ASTM D445”), IBR approved for § 1065.703(b). (6) ASTM D525-12a, Standard Test Method for Oxidation Stability of Gasoline (Induction Period Method), approved September 1, 2012 (“ASTM D525”), IBR approved for § 1065.710(b). (7) ASTM D613-13, Standard Test Method for Cetane Number of Diesel Fuel Oil, approved December 1, 2013 (“ASTM D613”), IBR approved for § 1065.703(b). (8) ASTM D910-13a, Standard Specification for Aviation Gasolines, approved December 1, 2013 (“ASTM D910”), IBR approved for § 1065.701(f). (9) ASTM D975-13a, Standard Specification for Diesel Fuel Oils, approved December 1, 2013 (“ASTM D975”), IBR approved for § 1065.701(f). (10) ASTM D1267-12, Standard Test Method for Gage Vapor Pressure of Liquefied Petroleum (LP) Gases (LP-Gas Method), approved November 1, 2012 (“ASTM D1267”), IBR approved for § 1065.720(a). (11) ASTM D1319-13, Standard Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption, approved May 1, 2013 (“ASTM D1319”), IBR approved for § 1065.710(c). (12) ASTM D1655-13a, Standard Specification for Aviation Turbine Fuels, approved December 1, 2013 (“ASTM D1655”), IBR approved for § 1065.701(f). (13) ASTM D1837-11, Standard Test Method for Volatility of Liquefied Petroleum (LP) Gases, approved October 1, 2011 (“ASTM D1837”), IBR approved for § 1065.720(a). (14) ASTM D1838-12a, Standard Test Method for Copper Strip Corrosion by Liquefied Petroleum (LP) Gases, approved December 1, 2012 (“ASTM D1838”), IBR approved for § 1065.720(a). (15) ASTM D1945-03 (Reapproved 2010), Standard Test Method for Analysis of Natural Gas by Gas Chromatography, approved January 1, 2010 (“ASTM D1945”), IBR approved for § 1065.715(a). (16) ASTM D2158-11, Standard Test Method for Residues in Liquefied Petroleum (LP) Gases, approved January 1, 2011 (“ASTM D2158”), IBR approved for § 1065.720(a). (17) ASTM D2163-07, Standard Test Method for Determination of Hydrocarbons in Liquefied Petroleum (LP) Gases and Propane/Propene Mixtures by Gas Chromatography, approved December 1, 2007 (“ASTM D2163”), IBR approved for § 1065.720(a). (18) ASTM D2598-12, Standard Practice for Calculation of Certain Physical Properties of Liquefied Petroleum (LP) Gases from Compositional Analysis, approved November 1, 2012 (“ASTM D2598”), IBR approved for § 1065.720(a). (19) ASTM D2622-16, Standard Test Method for Sulfur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectrometry, approved January 1, 2016 (“ASTM D2622”), IBR approved for §§ 1065.703(b) and 1065.710(b) and (c). (20) ASTM D2699-13b, Standard Test Method for Research Octane Number of Spark-Ignition Engine Fuel, approved October 1, 2013 (“ASTM D2699”), IBR approved for § 1065.710(b). (21) ASTM D2700-13b, Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel, approved October 1, 2013 (“ASTM D2700”), IBR approved for § 1065.710(b). (22) ASTM D2713-13, Standard Test Method for Dryness of Propane (Valve Freeze Method), approved October 1, 2013 (“ASTM D2713”), IBR approved for § 1065.720(a). (23) ASTM D2880-13b, Standard Specification for Gas Turbine Fuel Oils, approved November 15, 2013 (“ASTM D2880”), IBR approved for § 1065.701(f). (24) ASTM D2986-95a, Standard Practice for Evaluation of Air Assay Media by the Monodisperse DOP (Dioctyl Phthalate) Smoke Test, approved September 10, 1995 (“ASTM D2986”), IBR approved for § 1065.170(c). ( Note: (25) ASTM D3231-13, Standard Test Method for Phosphorus in Gasoline, approved June 15, 2013 (“ASTM D3231”), IBR approved for § 1065.710(b) and (c). (26) ASTM D3237-12, Standard Test Method for Lead in Gasoline By Atomic Absorption Spectroscopy, approved June 1, 2012 (“ASTM D3237”), IBR approved for § 1065.710(b) and (c). (27) ASTM D4052-11, Standard Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter, approved October 15, 2011 (“ASTM D4052”), IBR approved for § 1065.703(b). (28) ASTM D4629-12, Standard Test Method for Trace Nitrogen in Liquid Petroleum Hydrocarbons by Syringe/Inlet Oxidative Combustion and Chemiluminescence Detection, approved April 15, 2012 (“ASTM D4629”), IBR approved for § 1065.655(e). (29) ASTM D4814-13b, Standard Specification for Automotive Spark-Ignition Engine Fuel, approved December 1, 2013 (“ASTM D4814”), IBR approved for § 1065.701(f). (30) ASTM D4815-13, Standard Test Method for Determination of MTBE, ETBE, TAME, DIPE, tertiary-Amyl Alcohol and C1 to C4 Alcohols in Gasoline by Gas Chromatography, approved October 1, 2013 (“ASTM D4815”), IBR approved for § 1065.710(b). (31) ASTM D5186-03 (Reapproved 2009), Standard Test Method for Determination of the Aromatic Content and Polynuclear Aromatic Content of Diesel Fuels and Aviation Turbine Fuels By Supercritical Fluid Chromatography, approved April 15, 2009 (“ASTM D5186”), IBR approved for § 1065.703(b). (32) ASTM D5191-13, Standard Test Method for Vapor Pressure of Petroleum Products (Mini Method), approved December 1, 2013 (“ASTM D5191”), IBR approved for § 1065.710(b) and (c). (33) ASTM D5291-10, Standard Test Methods for Instrumental Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants, approved May 1, 2010 (“ASTM D5291”), IBR approved for § 1065.655(e). (34) ASTM D5453-19a, Standard Test Method for Determination of Total Sulfur in Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel Engine Fuel, and Engine Oil by Ultraviolet Fluorescence, approved July 1, 2019 (“ASTM D5453”), IBR approved for §§ 1065.703(b) and 1065.710(b). (35) ASTM D5599-00 (Reapproved 2010), Standard Test Method for Determination of Oxygenates in Gasoline by Gas Chromatography and Oxygen Selective Flame Ionization Detection, approved October 1, 2010 (“ASTM D5599”), IBR approved for §§ 1065.655(e) and 1065.710(b). (36) ASTM D5762-12 Standard Test Method for Nitrogen in Petroleum and Petroleum Products by Boat-Inlet Chemiluminescence, approved April 15, 2012 (“ASTM D5762”), IBR approved for § 1065.655(e). (37) ASTM D5769-10, Standard Test Method for Determination of Benzene, Toluene, and Total Aromatics in Finished Gasolines by Gas Chromatography/Mass Spectrometry, approved May 1, 2010 (“ASTM D5769”), IBR approved for § 1065.710(b). (38) ASTM D5797-13, Standard Specification for Fuel Methanol (M70- M85) for Automotive Spark-Ignition Engines, approved June 15, 2013 (“ASTM D5797”), IBR approved for § 1065.701(f). (39) ASTM D5798-13a, Standard Specification for Ethanol Fuel Blends for Flexible Fuel Automotive Spark-Ignition Engines, approved June 15, 2013 (“ASTM D5798”), IBR approved for § 1065.701(f). (40) ASTM D6348-12 1 (41) ASTM D6550-10, Standard Test Method for Determination of Olefin Content of Gasolines by Supercritical-Fluid Chromatography, approved October 1, 2010 (“ASTM D6550”), IBR approved for § 1065.710(b). (42) ASTM D6615-11a, Standard Specification for Jet B Wide-Cut Aviation Turbine Fuel, approved October 1, 2011 (“ASTM D6615”), IBR approved for § 1065.701(f). (43) ASTM D6667-14 (Reapproved 2019), Standard Test Method for Determination of Total Volatile Sulfur in Gaseous Hydrocarbons and Liquefied Petroleum Gases by Ultraviolet Fluorescence, approved May 1, 2019 (“ASTM D6667”), IBR approved for § 1065.720(a). (44) ASTM D6751-12, Standard Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate Fuels, approved August 1, 2012 (“ASTM D6751”), IBR approved for § 1065.701(f). (45) ASTM D6985-04a, Standard Specification for Middle Distillate Fuel Oil—Military Marine Applications, approved November 1, 2004 (“ASTM D6985”), IBR approved for § 1065.701(f). (Note: This standard was withdrawn by ASTM.) (46) ASTM D7039-15a (Reapproved 2020), Standard Test Method for Sulfur in Gasoline, Diesel Fuel, Jet Fuel, Kerosine, Biodiesel, Biodiesel Blends, and Gasoline-Ethanol Blends by Monochromatic Wavelength Dispersive X-ray Fluorescence Spectrometry, approved May 1, 2020 (“ASTM D7039”), IBR approved for §§ 1065.703(b) and 1065.710(b). (47) ASTM F1471-09, Standard Test Method for Air Cleaning Performance of a High- Efficiency Particulate Air Filter System, approved March 1, 2009 (“ASTM F1471”), IBR approved for § 1065.1001. (b) California Air Resources Board material. http://www.arb.ca.gov (1) California Non-Methane Organic Gas Test Procedures, Amended July 30, 2002, Mobile Source Division, California Air Resources Board, IBR approved for § 1065.805(f). (2) [Reserved] (c) Institute of Petroleum material. http://www.energyinst.org (1) IP-470, 2005, Determination of aluminum, silicon, vanadium, nickel, iron, calcium, zinc, and sodium in residual fuels by atomic absorption spectrometry, IBR approved for § 1065.705(b). (2) IP-500, 2003, Determination of the phosphorus content of residual fuels by ultra-violet spectrometry, IBR approved for § 1065.705(b). (3) IP-501, 2005, Determination of aluminum, silicon, vanadium, nickel, iron, sodium, calcium, zinc and phosphorus in residual fuel oil by ashing, fusion and inductively coupled plasma emission spectrometry, IBR approved for § 1065.705(b). (d) ISO material. http://www.iso.org (1) ISO 2719:2002, Determination of flash point—Pensky-Martens closed cup method (“ISO 2719”), IBR approved for § 1065.705(c). (2) ISO 3016:1994, Petroleum products—Determination of pour point (“ISO 3016”), IBR approved for § 1065.705(c). (3) ISO 3104:1994/Cor 1:1997, Petroleum products—Transparent and opaque liquids—Determination of kinematic viscosity and calculation of dynamic viscosity (“ISO 3104”), IBR approved for § 1065.705(c). (4) ISO 3675:1998, Crude petroleum and liquid petroleum products—Laboratory determination of density—Hydrometer method (“ISO 3675”), IBR approved for § 1065.705(c). (5) ISO 3733:1999, Petroleum products and bituminous materials—Determination of water—Distillation method (“ISO 3733”), IBR approved for § 1065.705(c). (6) ISO 6245:2001, Petroleum products—Determination of ash (“ISO 6245”), IBR approved for § 1065.705(c). (7) ISO 8217:2012(E), Petroleum products—Fuels (class F)—Specifications of marine fuels, Fifth edition, August 15, 2012 (“ISO 8217”), IBR approved for § 1065.705(b) and (c). (8) ISO 8754:2003, Petroleum products—Determination of sulfur content—Energy-dispersive X-ray Fluorescence spectrometry (“ISO 8754”), IBR approved for § 1065.705(c). (9) ISO 10307-2(E):2009, Petroleum products—Total sediment in residual fuel oils—Part 2: Determination using standard procedures for ageing, Second Ed., February 1, 2009 (“ISO 10307”), as modified by ISO 10307-2:2009/Cor.1:2010(E), Technical Corrigendum 1, published May 15, 2010, IBR approved for § 1065.705(c). (10) ISO 10370:1993/Cor 1:1996, Petroleum products—Determination of carbon residue—Micro method (“ISO 10370”), IBR approved for § 1065.705(c). (11) ISO 10478:1994, Petroleum products—Determination of aluminium and silicon in fuel oils—Inductively coupled plasma emission and atomic absorption spectroscopy methods (“ISO 10478”), IBR approved for § 1065.705(c). (12) ISO 12185:1996/Cor 1:2001, Crude petroleum and petroleum products—Determination of density—Oscillating U-tube method (“ISO 12185”), IBR approved for § 1065.705(c). (13) ISO 14596:2007, Petroleum products—Determination of sulfur content—Wavelength-dispersive X-ray fluorescence spectrometry (“ISO 14596”), IBR approved for § 1065.705(c). (14) ISO 14597:1997, Petroleum products—Determination of vanadium and nickel content—Wavelength dispersive X-ray fluorescence spectrometry (“ISO 14597”), IBR approved for § 1065.705(c). (15) ISO 14644-1:1999, Cleanrooms and associated controlled environments (“ISO 14644”), IBR approved for § 1065.190(b). (e) NIST material. www.nist.gov (1) NIST Special Publication 811, 2008 Edition, Guide for the Use of the International System of Units (SI), March 2008, IBR approved for §§ 1065.20(a) and 1065.1005. (2) NIST Technical Note 1297, 1994 Edition, Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results, IBR approved for §§ 1065.365(g), 1065.750(a), and 1065.1001. (f) SAE International material. http://www.sae.org (1) SAE 770141, 1977, Optimization of Flame Ionization Detector for Determination of Hydrocarbon in Diluted Automotive Exhausts, Glenn D. Reschke, IBR approved for § 1065.360(c). (2) SAE J1151, Methane Measurement Using Gas Chromatography, stabilized September 2011, IBR approved for §§ 1065.267(b) and 1065.750(a). [79 FR 23818, Apr. 28, 2014, as amended at 81 FR 74193, Oct. 25, 2016; 85 FR 78468, Dec. 4, 2020; 86 FR 34579, June 29, 2021; 88 FR 4690, Jan. 24, 2023; 89 FR 29826, Apr. 22, 2024] Subpart L—Methods for Unregulated and Special Pollutants and Additional Procedures Source: 79 FR 23820, Apr. 28, 2014, unless otherwise noted. § 1065.1101 Applicability. This subpart specifies procedures that may be used to measure emission constituents that are not measured (or not separately measured) by the test procedures in the other subparts of this part. These procedures are included to facilitate consistent measurement of unregulated pollutants for purposes other than compliance with emission standards. Unless otherwise specified in the standard-setting part, use of these procedures is optional and does not replace any requirements in the rest of this part. Semi-Volatile Organic Compounds § 1065.1103 General provisions for SVOC measurement. The provisions of §§ 1065.1103 through 1065.1111 specify procedures for measuring semi-volatile organic compounds (SVOC) along with PM. These sections specify how to collect a sample of the SVOCs during exhaust emission testing, as well as how to use wet chemistry techniques to extract SVOCs from the sample media for analysis. Note that the precise method you use will depend on the category of SVOCs being measured. For example, the method used to measure polynuclear aromatic hydrocarbons (PAHs) will differ slightly from the method used to measure dioxins. Follow standard analytic chemistry methods for any aspects of the analysis that are not specified. (a) Laboratory cleanliness is especially important throughout SVOC testing. Thoroughly clean all sampling system components and glassware before testing to avoid sample contamination. For the purposes of this subpart, the sampling system is defined as sample pathway from the sample probe inlet to the downstream most point where the sample is captured (in this case the condensate trap). (b) We recommend that media blanks be analyzed for each batch of sample media (sorbent, filters, etc.) prepared for testing. Blank sorbent modules (i.e., field blanks) should be stored in a sealed environment and should periodically accompany the test sampling system throughout the course of a test, including sampling system and sorbent module disassembly, sample packaging, and storage. Use good engineering judgment to determine the frequency with which you should generate field blanks. The field blank sample should be close to the sampler during testing. (c) We recommend the use of isotope dilution techniques, including the use of isotopically labeled surrogate, internal, alternate, and injection standards. (d) If your target analytes degrade when exposed to ultraviolet radiation, such as nitropolynuclear aromatic hydrocarbons (nPAHs), perform these procedures in the dark or with ultraviolet filters installed over the lights. (e) The following definitions and abbreviations apply for SVOC measurements: (1) Soxhlet extraction (2) XAD-2 (3) Semi-volatile organic compound (SVOC) (4) Kuderna-Danish concentrator (5) Dean-Stark trap (6) PUF (7) Isotopically labeled § 1065.1105 Sampling system design. (a) General. (b) Sample probe, transfer lines, and sample media holder design and construction. (c) Sample system configuration. (1) Use a sample probe similar to the PM sample probe specified in subpart B of this part. (2) Use a PM filter holder similar to the holder specified in subpart B of this part, although you will likely need to use a larger size to accommodate the high sample flow rates. We recommend using a 110 mm filter for testing spark ignition engines or engines that utilize exhaust aftertreatment for PM removal and a 293 mm filter for other engines. If you are not analyzing separately for SVOCs in gas and particle phases, you do not have to control the temperature of the filter holder. Note that this differs from normal PM sampling procedures, which maintain the filter at a much lower temperature to capture a significant fraction of exhaust SVOC on the filter. In this method, SVOCs that pass through the filter will be collected on the downstream sorbent module. If you are collecting SVOCs in gas and particle phases, control your filter face temperature according to § 1065.140(e)(4). (3) Use good engineering judgment to design a cooling coil that will drop the sample temperature to approximately 5 °C. Note that downstream of the cooling coil, the sample will be a mixture of vapor phase hydrocarbons in CO 2 (4) Use a hydrophobic sorbent in a sealed sorbent module. Note that this sorbent module is intended to be the final stage for collecting the SVOC sample and should be sized accordingly. We recommend sizing the module to hold 40 g of XAD-2 along with PUF plugs at either end of the module, noting that you may vary the mass of XAD used for testing based on the anticipated SVOC emission concentration and sample flow rate. (5) Include a condensate trap to separate the aqueous liquid phase from the gas stream. We recommend using a peristaltic pump to remove water from the condensate trap over the course of the test to prevent build-up of the condensate. Note that for some tests it may be appropriate to collect this water for analysis. (d) Sampler flow control. (e) Water bath. [79 FR 23820, Apr. 28, 2014, as amended at 81 FR 74195, Oct. 25, 2016] § 1065.1107 Sample media and sample system preparation; sample system assembly. This section describes the appropriate types of sample media and the cleaning procedure required to prepare the media and wetted sample surfaces for sampling. (a) Sample media. (1) For capturing PM, we recommend using pure quartz filters with no binder if you are not analyzing separately for SVOCs in gas and particle phases. If you are analyzing separately, you must use polytetrafluoroethylene (PTFE) filters with PTFE support. Select the filter diameter to minimize filter change intervals, accounting for the expected PM emission rate, sample flow rate. Note that when repeating test cycles to increase sample mass, you may replace the filter without replacing the sorbent or otherwise disassembling the batch sampler. In those cases, include all filters in the extraction. (2) For capturing gaseous SVOCs, utilize XAD-2 resin with or without PUF plugs. Note that two PUF plugs are typically used to contain the XAD-2 resin in the sorbent module. (b) Sample media and sampler preparation. (1) Pre-clean the filters via Soxhlet extraction with methylene chloride for 24 hours and dry over dry nitrogen in a low-temperature vacuum oven. (2) Pre-clean PUF and XAD-2 with a series of Soxhlet extractions: 8 hours with water, 22 hours with methanol, 22 hours with methylene chloride, and 22 hours with toluene, followed by drying with nitrogen. (3) Clean sampler components, including the probe, filter holder, condenser, sorbent module, and condensate collection vessel by rinsing three times with methylene chloride and then three times with toluene. Prepare pre-cleaned aluminum foil for capping the probe inlet of the sampler after the sampling system has been assembled. (c) Sorbent spiking. (1) Insert the lower PUF plug into the bottom of the sorbent module. (2) Add half of one portion of XAD-2 resin to the module and spike the XAD-2 in the module with the standard. (3) Wait 1 hour for the solvent from the standard(s) to evaporate, add the remaining 20 g of the XAD-2 resin to the module, and then insert a PUF plug in the top of the sorbent module. (4) Cover the inlet and outlet of the sorbent module with pre-cleaned aluminum foil. (d) Sampling system assembly. [79 FR 23820, Apr. 28, 2014, as amended at 81 FR 74195, Oct. 25, 2016] § 1065.1109 Post-test sampler disassembly and sample extraction. This section describes the process for disassembling and rinsing the sampling system and extracting and cleaning up the sample. (a) Sampling system disassembly. (1) Remove the PM filter, PUF plugs, and all the XAD-2 from the sampling system and store them at or below 5 °C until analysis. (2) Rinse sampling system wetted surfaces upstream of the condensate trap with acetone followed by toluene (or a comparable solvent system), ensuring that all the solvent remaining in liquid phase is collected (note that a fraction of the acetone and toluene will likely be lost to evaporation during mixing). Rinse with solvent volumes that are sufficient to cover all the surfaces exposed to the sample during testing. We recommend three fresh solvent rinses with acetone and two with toluene. We recommend rinse volumes of 60 ml per rinse for all sampling system components except the condenser coil, of which you should use 200 ml per rinse. Keep the acetone rinsate separate from the toluene rinsate to the extent practicable. Rinsate fractions should be stored separately in glass bottles that have been pre-rinsed with acetone, hexane, and toluene (or purchase pre-cleaned bottles). (3) Use good engineering judgment to determine if you should analyze the aqueous condensate phase for SVOCs. If you determine that analysis is necessary, use toluene to perform a liquid-liquid extraction of the SVOCs from the collected aqueous condensate using a separatory funnel or an equivalent method. Add the toluene from this aqueous extraction to the toluene rinsate fraction described in paragraph (a)(2) of this section. (4) Reduce rinsate solvent volumes as needed using a Kuderna-Danish concentrator or rotary evaporator and retain these rinse solvents for reuse during sample media extraction for the same test. Be careful to avoid loss of low molecular weight analytes when concentrating with rotary evaporation. (b) Sample extraction. (1) We recommend equipping the Soxhlet extractor with a Dean-Stark trap to facilitate removal of residual water from the sampling system rinse. The Soxhlet apparatus must be large enough to allow extraction of the PUF, XAD-2, and filter in a single batch. Include in the extractor setup a glass thimble with a coarse or extra coarse sintered glass bottom. Pre-clean the extractor using proper glass-cleaning procedures. We recommend that the Soxhlet apparatus be cleaned with a (4 to 8) hour Soxhlet extraction with methylene chloride at a cycling rate of three cycles per hour. Discard the solvent used for pre-cleaning (no analysis is necessary). (2) Load the extractor thimble before placing it in the extractor by first rolling the PM filter around the inner circumference of the thimble, with the sampled side facing in. Push one PUF plug down into the bottom of the thimble, add approximately half of the XAD-2, and then spike the XAD-2 in the thimble with the isotopically labeled extraction standards of known mass. Target the center of the XAD-2 bed for delivering the extraction standard. We recommend using multiple isotopically labeled extraction standards that cover the range of target analytes. This generally means that you should use isotopically labeled standards at least for the lowest and highest molecular weight analytes for each category of compounds (such as PAHs and dioxins). These extraction standards monitor the efficiency of the extraction and are also used to determine analyte concentrations after analysis. Upon completion of spiking, add the remaining XAD-2 to the thimble, insert the remaining PUF plug, and place the thimble into the extractor. Note that if you are collecting and analyzing for SVOCs in gas and particle phases, perform separate extractions for the filter and XAD-2. (3) For the initial extraction, combine the concentrated acetone rinses (from the sampling system in paragraph (a) of this section) with enough hexane to bring the solvent volume up to the target level of 700 ml. Assemble the extractor and turn on the heating controls and cooling water. Allow the sample to reflux for 16 hours with the rheostat adjusted to cycle the extraction at a rate of (3.0 ±0.5) cycles per hour. Drain the water from the Dean-Stark trap as it accumulates by opening the stopcock on the trap. Set aside the water for analysis or discard it. In most cases, any water present will be removed within approximately 2 hours after starting the extraction. (4) After completing the initial extraction, remove the solvent and concentrate it to (4.0 ±0.5) ml using a Kuderna-Danish concentrator that includes a condenser such as a three-ball Snyder column with venting dimples and a graduated collection tube. Hold the water bath temperature at (75 to 80) °C. Using this concentrator will minimize evaporative loss of analytes with lower molecular weight. (i) Rinse the round bottom flask of the extractor with (60 to 100) ml of hexane and add the rinsate to this concentrated extract. (ii) Concentrate the mixture to (4 ±0.5) ml using a Kuderna-Danish concentrator or similar apparatus. (iii) Repeat the steps in paragraphs (b)(4)(i) and (ii) of this section three times, or as necessary to remove all the residual solvent from the round bottom flask of the extractor, concentrating the final rinsate to (4 ±0.5) ml. (5) For the second extraction, combine the toluene rinses (from the sampling system in paragraph (a) of this section) with any additional toluene needed to bring the solvent volume up to the target level of 700 ml. As noted in paragraph (a) of this section, you may need to concentrate the rinsate before adding it to the extraction apparatus if the rinsate solvent volume is too large. Allow the sample to reflux for 16 hours with the rheostat adjusted to cycle the extraction at a rate of (3.0 ±0.5) cycles per hour. Check the Dean-Stark trap for water during the first 2 hours of the extraction (though little or no water should be present during this stage). (6) Upon completion of the second extraction, remove the solvent and concentrate it to (4 ±0.5) ml as described in paragraph (b)(4) of this section. Using hexane from paragraph (b)(4) of this section as the rinse solvent effectively performs a solvent exchange of toluene with hexane. (7) Combine the concentrated extract from paragraph (b)(4) of this section with the concentrated extract from paragraph (b)(6) of this section. Divide the extract into a number of fractions based on the number of analyses you need to perform. Perform the separate sample clean-up described in paragraph (c) of this section as needed for each fraction. (c) Sample clean-up. (1) PAH clean-up. (i) Pack a glass gravity column (250 mm × 10 mm recommended) by inserting a clean glass wool plug into the bottom of the column and add 10 g of activated silica gel in methylene chloride. Tap the column to settle the silica gel and then add a 1 cm layer of anhydrous sodium sulfate. Verify the volume of solvent required to completely elute all the PAHs and adjust the weight of the silica gel accordingly to account for variations among batches of silica gel that may affect the elution volume of the various PAHs. (ii) Elute the column with 40 ml of hexane. The rate for all elutions should be about 2 ml/min. You may increase the elution rate by using dry air or nitrogen to maintain the headspace slightly above atmospheric pressure. Discard the eluate just before exposing the sodium sulfate layer to the air or nitrogen and transfer the 1 ml sample extract onto the column using two additional 2 ml rinses of hexane. Just before exposing the sodium sulfate layer to the air or nitrogen, begin elution of the column with 25 ml of hexane followed by 25 ml of 40 volume % methylene chloride in hexane. Collect the entire eluate and concentrate it to about 5 ml using the Kuderna-Danish concentrator or a rotary evaporator. Make sure not to evaporate all the solvent from the extract during the concentration process. Transfer the eluate to a small sample vial using a hexane rinse and concentrate it to 100 µl using a stream of nitrogen without violently disturbing the solvent. Store the extracts in a refrigerator at or below 4 °C, and away from light. (2) nPAH clean up. et al (i) Condition an aminopropyl solid phase extraction (SPE) cartridge by eluting it with 20 ml of 20 volume % methylene chloride in hexane. Transfer the extract quantitatively to the SPE cartridge with at least two methylene chloride rinses. Elute the extract through the SPE cartridge by using 40 ml of 20 volume % methylene chloride in hexane to minimize potential interference of polar constituents, and then reduce the extract to 0.5 ml in hexane and subject it to normal-phase liquid chromatography using a pre-prepared 9.6 mm × 25 cm semi-preparative Chromegabond® amino/cyano column (5 µm particle size) to isolate the nPAH fraction. The mobile phase is 20 volume % methylene chloride in hexane at a constant flow rate of 5 ml per minute. Back-flash the column with 60 ml of methylene chloride and then condition it with 200 ml of 20 volume % methylene chloride in hexane before each injection. Collect the effluent and concentrate it to about 2 ml using the Kuderna-Danish concentrator or a rotary evaporator. Transfer it to a minivial using a hexane rinse and concentrate it to 100 µl using a gentle stream of nitrogen. Store the extracts at or below 4 °C, and away from light. (ii) [Reserved] [79 FR 23820, Apr. 28, 2014, as amended at 81 FR 74195, Oct. 25, 2016] § 1065.1111 Sample analysis. This subpart does not specify chromatographic or analytical methods to analyze extracts, because the appropriateness of such methods is highly dependent on the nature of the target analytes. However, we recommend that you spike the extract with an injection standard that contains a known mass of an isotopically labeled compound that is identical to one of the target analytes (except for labeling). This injection standard allows you to monitor the efficiency of the analytical process by verifying the volume of sample injected for analysis. Vanadium Sublimation In SCR Catalysts Source: Sections 1065.1113 through 1065.1119 appear at 88 FR 4691, Jan. 24, 2023, unless otherwise noted. § 1065.1113 General provisions related to vanadium sublimation temperatures in SCR catalysts. Sections 1065.1113 through 1065.1121 specify procedures for determining vanadium emissions from a catalyst based on catalyst temperature. Vanadium can be emitted from the surface of SCR catalysts at temperatures above 550 °C, dependent on the catalyst formulation. These procedures are appropriate for measuring the vanadium sublimation product from a reactor by sampling onto an equivalent mass of alumina and performing analysis by Inductively Coupled Plasma—Optical Emission Spectroscopy (ICP-OES). Follow standard analytic chemistry methods for any aspects of the analysis that are not specified. (a) The procedure is adapted from “Behavior of Titania-supported Vanadia and Tungsta SCR Catalysts at High Temperatures in Reactant Streams: Tungsten and Vanadium Oxide and Hydroxide Vapor Pressure Reduction by Surficial Stabilization” (Chapman, D.M., Applied Catalysis A: General, 2011, 392, 143-150) with modifications to the acid digestion method from “Measuring the trace elemental composition of size-resolved airborne particles” (Herner, J.D. et al, (b) Laboratory cleanliness is especially important throughout vanadium testing. Thoroughly clean all sampling system components and glassware before testing to avoid sample contamination. § 1065.1115 Reactor design and setup. Vanadium measurements rely on a reactor that adsorbs sublimation vapors of vanadium onto an alumina capture bed with high surface area. (a) Configure the reactor with the alumina capture bed downstream of the catalyst in the reactor's hot zone to adsorb vanadium vapors at high temperature. You may use quartz beads upstream of the catalyst to help stabilize reactor gas temperatures. Select an alumina material and design the reactor to minimize sintering of the alumina. For a 1-inch diameter reactor, use 4 to 5 g of 1/8 (b) Include the quartz wool with the capture bed to measure vanadium content. We recommend analyzing the downstream quartz wool separately from the alumina to see if the alumina fails to capture some residual vanadium. (c) Configure the reactor such that both the sample and capture beds are in the reactor's hot zone. Design the reactor to maintain similar temperatures in the capture bed and catalyst. Monitor the catalyst and alumina temperatures with Type K thermocouples inserted into a thermocouple well that is in contact with the catalyst sample bed. (d) If there is a risk that the quartz wool and capture bed are not able to collect all the vanadium, configure the reactor with an additional capture bed and quartz wool plug just outside the hot zone and analyze the additional capture bed and quartz wool separately. (e) An example of a catalyst-coated monolith and capture bed arrangement in the reactor tube are shown in the following figure: Figure 1 to paragraph (e) of § 1065.1115— Example of Reactor Setup (f) You may need to account for vanadium-loaded particles contaminating catalyst-coated monoliths as a result of physical abrasion. To do this, determine how much titanium is in the capture bed and compare to an alumina blank. Using these values and available information about the ratio of vanadium to titanium in the catalyst, subtract the mass of vanadium catalyst material associated with the catalyst particles from the total measured vanadium on the capture bed to determine the vanadium recovered due to sublimation. § 1065.1117 Reactor aging cycle for determination of vanadium sublimation temperature. This section describes the conditions and process required to operate the reactor described in § 1065.1115 for collection of the vanadium sublimation samples for determination of vanadium sublimation temperature. The reactor aging cycle constitutes the process of testing the catalyst sample over all the test conditions described in paragraph (b) of this section. (a) Set up the reactor to flow gases with a space velocity of at least 35,000/hr with a pressure drop across the catalyst and capture beds less than 35 kPa. Use test gases meeting the following specifications, noting that not all gases will be used at the same time: (1) 5 vol% O 2 2 (2) NO, balance N 2 (3) NH 3 2 3 (b) Perform testing as follows: (1) Add a new catalyst sample and capture bed into the reactor as described in § 1065.1113. Heat the reactor to 550 °C while flowing the oxygen blend specified in paragraph (a)(1) of this section as a pretest gas mixture. Ensure that no H 2 (2) Start testing at a temperature that is lower than the point at which vanadium starts to sublime. Start testing when the reactor reaches 550 °C unless testing supports a lower starting temperature. Once the reactor reaches the starting temperature and the catalyst has been equilibrated to the reactor temperature, flow NO and NH 3 2 (3) After 18 hours of exposure, flow the pretest oxygen blend as specified in paragraph (b)(1) of this section and allow the reactor to cool down to room temperature. (4) Analyze the sample as described in § 1065.1121. (5) Repeat the testing in paragraphs (b)(1) through (4) of this section by raising the reactor temperature in increments of 50 °C up to the temperature at which vanadium sublimation begins. (6) Once sublimation has been detected, repeat the testing in paragraphs (b)(1) through (4) of this section by decreasing the reactor temperature in increments of 25 °C until the vanadium concentration falls below the sublimation threshold. (7) Repeat the testing in paragraphs (b)(1) through (6) of this section with a nominal H 2 (8) You may optionally test in a manner other than testing a single catalyst formulation in series across all test temperatures. For example, you may test additional samples at the same reactor temperature before moving on to the next temperature. (c) The effective sublimation temperature for the tested catalyst is the lowest reactor temperature determined in paragraph (b) of this section below which vanadium emissions are less than the method detection limit. § 1065.1119 Blank testing. This section describes the process for analyzing blanks. Use blanks to determine the background effects and the potential for contamination from the sampling process. (a) Take blanks from the same batch of alumina used for the capture bed. (b) Media blanks are used to determine if there is any contamination in the sample media. Analyze at least one media blank for each reactor aging cycle or round of testing performed under § 1065.1117. If your sample media is taken from the same lot, you may analyze media blanks less frequently consistent with good engineering judgment. (c) Field blanks are used to determine if there is any contamination from environmental exposure of the sample media. Analyze at least one field blank for each reactor aging cycle or round of testing performed under § 1065.1117. Field blanks must be contained in a sealed environment and accompany the reactor sampling system throughout the course of a test, including reactor disassembly, sample packaging, and storage. Use good engineering judgment to determine how frequently to generate field blanks. Keep the field blank sample close to the reactor during testing. (d) Reactor blanks are used to determine if there is any contamination from the sampling system. Analyze at least one reactor blank for each reactor aging cycle or round of testing performed under § 1065.1117. (1) Test reactor blanks with the reactor on and operated identically to that of a catalyst test in § 1065.1117 with the exception that when loading the reactor, only the alumina capture bed will be loaded (no catalyst sample is loaded for the reactor blank). We recommend acquiring reactor blanks with the reactor operating at average test temperature you used when acquiring your test samples under § 1065.1117. (2) You must run at least three reactor blanks if the result from the initial blank analysis is above the detection limit of the method, with additional blank runs based on the uncertainty of the reactor blank measurements, consistent with good engineering judgment. § 1065.1121 Vanadium sample dissolution and analysis in alumina capture beds. This section describes the process for dissolution of vanadium from the vanadium sublimation samples collect in § 1065.1117 and any blanks collected in § 1065.1119 as well as the analysis of the digestates to determine the mass of vanadium emitted and the associated sublimation temperature threshold based on the results of all the samples taken during the reactor aging cycle. (a) Digest the samples using the following procedure, or an equivalent procedure: (1) Place the recovered alumina, a portion of the ground quartz tube from the reactor, and the quartz wool in a Teflon pressure vessel with a mixture made from 1.5 mL of 16 N HNO 3 (2) Program a microwave oven to heat the sample to 180 °C over 9 minutes, followed by a 10-minute hold at that temperature, and 1 hour of ventilation/cooling. (3) After cooling, dilute the digests to 30 mL with high purity 18MΩ water prior to ICP-MS (or ICP-OES) analysis. Note that this digestion technique requires adequate safety measures when working with HF at high temperature and pressure. To avoid “carry-over” contamination, rigorously clean the vessels between samples as described in “Microwave digestion procedures for environmental matrixes” (Lough, G.C. et al, (b) Analyze the digestates for vanadium as follows: (1) Perform the analysis using ICP-OES (or ICP-MS) using standard plasma conditions (1350 W forward power) and a desolvating microconcentric nebulizer, which will significantly reduce oxide- and chloride-based interferences. (2) We recommend that you digest and analyze a minimum of three solid vanadium NIST Standard Reference Materials in duplicate with every batch of 25 vanadium alumina capture bed samples that you analyze in this section, as described in “Emissions of metals associated with motor vehicle roadways” (Herner, J.D. et al, (3) Use the 3-sigma approach to determine the analytical method detection limits for vanadium and the 10-sigma approach if you determine the reporting limit. This process involves analyzing at least seven replicates of a reactor blank using the analytical method described in paragraphs (a) and (b)(1) of this section, converting the responses into concentration units, and calculating the standard deviation. Determine the detection limit by multiplying the standard deviation by 3 and adding it to the average. Determine the reporting limit by multiplying the standard deviation by 10 and adding it to the average. Determine the following analytical method detection limits: (i) Determine the ICP-MS (or ICP-OES) instrumental detection limit (ng/L) by measuring at least seven blank samples made up of the reagents from paragraph (a) of this section. (ii) Determine the method detection limit (µg/m 3 (iii) We recommend that your method detection limit determined under paragraph (b)(3)(ii) of this section is at or below 15 µg/m 3 (4) If you account for vanadium-loaded particles contaminating catalyst-coated monoliths as a result of physical abrasion as allowed in § 1065.1115(f), use the 3-sigma approach to determine the analytical method detection limits for titanium and the 10-sigma approach if you determine the reporting limit. This process involves analyzing at least seven replicates of a blank using the analytical method described in paragraphs (a) and (b)(1) of this section, converting the responses into concentration units, and calculating the standard deviation. Determine the detection limit by multiplying the standard deviation by 3 and subtracting it from the average. Determine the reporting limit by multiplying the standard deviation by 10 and subtracting it from the average. (i) Determine the ICP-MS (or ICP-OES) instrumental detection limit (ng/L) by measuring at least seven blank samples made up of the reagents from paragraph (a) of this section. (ii) Determine the method detection limit (µg/m 3 Smoke Opacity Source: Sections 1065.1123 through 1065.1127 appear at 88 FR 4693, Jan. 24, 2023, unless otherwise noted. § 1065.1123 General provisions for determining exhaust opacity. The provisions of § 1065.1125 describe system specifications for measuring percent opacity of exhaust for all types of engines. The provisions of § 1065.1127 describe how to use such a system to determine percent opacity of engine exhaust for applications other than locomotives. See 40 CFR 1033.525 for measurement procedures for locomotives. § 1065.1125 Exhaust opacity measurement system. Smokemeters measure exhaust opacity using full-flow open-path light extinction with a built-in light beam across the exhaust stack or plume. Prepare and install a smokemeter system as follows: (a) Except as specified in paragraph (d) of this section, use a smokemeter capable of providing continuous measurement that meets the following specifications: (1) Use an incandescent lamp with a color temperature between (2800 and 3250) K or a different light source with a spectral peak between (550 and 570) nm. (2) Collimate the light beam to a nominal diameter of 3 centimeters and maximum divergence angle of 6 degrees. (3) Include a photocell or photodiode as a detector. The detector must have a maximum spectral response between (550 and 570) nm, with less than 4 percent of that maximum response below 430 nm and above 680 nm. These specifications correspond to visual perception with the human eye. (4) Use a collimating tube with an aperture that matches the diameter of the light beam. Restrict the detector to viewing within a 16 degree included angle. (5) Optionally use an air curtain across the light source and detector window to minimize deposition of smoke particles, as long as it does not measurably affect the opacity of the sample. (6) The diagram in the following figure illustrates the smokemeter configuration: Figure 1 to paragraph (a)(6) of § 1065.1125—Smokemeter Diagram (b) Smokemeters for locomotive applications must have a full-scale response time of 0.5 seconds or less. Smokemeters for locomotive applications may attenuate signal responses with frequencies higher than 10 Hz with a separate low-pass electronic filter that has the following performance characteristics: (1) Three decibel point: 10 Hz. (2) Insertion loss: (0.0 ±0.5) dB. (3) Selectivity: 12 dB down at 40 Hz minimum. (4) Attenuation: 27 dB down at 40 Hz minimum. (c) Configure exhaust systems as follows for measuring exhaust opacity: (1) For locomotive applications: (i) Optionally add a stack extension to the locomotive muffler. (ii) For in-line measurements, the smokemeter is integral to the stack extension. (iii) For end-of-line measurements, mount the smokemeter directly at the end of the stack extension or muffler. (iv) For all testing, minimize distance from the optical centerline to the muffler outlet; in no case may it be more than 300 cm. The maximum allowable distance of unducted space upstream of the optical centerline is 50 cm, whether the unducted portion is upstream or downstream of the stack extensions. (2) Meet the following specifications for all other applications: (i) For in-line measurements, install the smokemeter in an exhaust pipe segment downstream of all engine components. This will typically be part of a laboratory configuration to route the exhaust to an analyzer. The exhaust pipe diameter must be constant within 3 exhaust pipe diameters before and after the smokemeter's optical centerline. The exhaust pipe diameter may not change by more than a 12-degree half-angle within 6 exhaust pipe diameters upstream of the smokemeter's optical centerline. (ii) For end-of-line measurements with systems that vent exhaust to the ambient, add a stack extension and position the smokemeter such that its optical centerline is (2.5 ±0.625) cm upstream of the stack extension's exit. Configure the exhaust stack and extension such that at least the last 60 cm is a straight pipe with a circular cross section with an approximate inside diameter as specified in the following table: Table 1 to Paragraph ( c ii Maximum rated power Approximate exhaust pipe diameter kW<40 38 40≤kW<75 50 75≤kW<150 76 150≤kW<225 102 225≤kW<375 127 kW ≥ 152 (iii) For both in-line and end-of-line measurements, install the smokemeter so its optical centerline is (3 to 10) meters further downstream than the point in the exhaust stream that is farthest downstream considering all the following components: exhaust manifolds, turbocharger outlets, exhaust aftertreatment devices, and junction points for combining exhaust flow from multiple exhaust manifolds. (3) Orient the light beam perpendicular to the direction of exhaust flow. Install the smokemeter so it does not influence exhaust flow distribution or the shape of the exhaust plume. Set up the smokemeter's optical path length as follows: (i) For locomotive applications, the optical path length must be at least as wide as the exhaust plume. (ii) For all other applications, the optical path length must be the same as the diameter of the exhaust flow. For noncircular exhaust configurations, set up the smokemeter such that the light beam's path length is across the longest axis with an optical path length equal to the hydraulic diameter of the exhaust flow. (4) The smokemeter must not interfere with the engine's ability to meet the exhaust backpressure requirements in § 1065.130(h). (5) For engines with multiple exhaust outlets, measure opacity using one of the following methods: (i) Join the exhaust outlets together to form a single flow path and install the smokemeter (3 to 10) m downstream of the point where the exhaust streams converge or the last exhaust aftertreatment device, whichever is farthest downstream. (ii) Install a smokemeter in each of the exhaust flow paths. Report all measured values. All measured values must comply with standards. (6) The smokemeter may use purge air or a different method to prevent carbon or other exhaust deposits on the light source and detector. Such a method used with end-of-line measurements may not cause the smoke plume to change by more than 0.5 cm at the smokemeter. If such a method affects the smokemeter's optical path length, follow the smokemeter manufacturer's instructions to properly account for that effect. (d) You may use smokemeters meeting alternative specifications as follows: (1) You may use smokemeters that use other electronic or optical techniques if they employ substantially identical measurement principles and produce substantially equivalent results. (2) You may ask us to approve the use of a smokemeter that relies on partial flow sampling. Follow the instrument manufacturer's installation, calibration, operation, and maintenance procedures if we approve your request. These procedures must include correcting for any change in the path length of the exhaust plume relative to the diameter of the engine's exhaust outlet. § 1065.1127 Test procedure for determining percent opacity. The test procedure described in this section applies for everything other than locomotives. The test consists of a sequence of engine operating points on an engine dynamometer to measure exhaust opacity during specific engine operating modes to represent in-use operation. Measure opacity using the following procedure: (a) Use the equipment and procedures specified in this part 1065. (b) Calibrate the smokemeter as follows: (1) Calibrate using neutral density filters with approximately 10, 20, and 40 percent opacity. Confirm that the opacity values for each of these reference filters are NIST-traceable within 185 days of testing, or within 370 days of testing if you consistently protect the reference filters from light exposure between tests. (2) Before each test and optionally during engine idle modes, remove the smokemeter from the exhaust stream, if applicable, and calibrate as follows: (i) Zero. (ii) Linearity. (c) Prepare the engine, dynamometer, and smokemeter for testing as follows: (1) Set up the engine to run in a configuration that represents in-use operation. (2) Determine the smokemeter's optical path length to the nearest mm. (3) If the smokemeter uses purge air or another method to prevent deposits on the light source and detector, adjust the system according to the system manufacturer's instructions and activate the system before starting the engine. (4) Program the dynamometer to operate in torque-control mode throughout testing. Determine the dynamometer load needed to meet the cycle requirements in paragraphs (d)(4)(ii) and (iv) of this section. (5) You may program the dynamometer to apply motoring assist with negative flywheel torque, but only during the first 0.5 seconds of the acceleration events in paragraphs (d)(4)(i) and (ii) of this section. Negative flywheel torque may not exceed 13.6 N·m. (d) Operate the engine and dynamometer over repeated test runs of the duty cycle illustrated in Figure 1 of this appendix. As noted in the figure, the test run includes an acceleration mode from points A through F in the figure, followed by a lugging mode from points I to J. Detailed specifications for testing apply as follows: (1) (2) Precondition the engine by operating it for 10 minutes at maximum mapped power. (3) Operate the engine for (5.0 to 5.5) minutes at warm idle speed, ƒ nidle, (4) Operate the engine and dynamometer as follows during the acceleration mode: (i) First acceleration event—AB. nidle. t (ii) Second acceleration event—CD. ntest, (iii) Transition—DEF. ntest, (iv) Third acceleration event—FGH. ntest (5) Operate the engine and dynamometer as follows during the lugging mode: (i) Transition—HI. ntest, ntest (ii) Lugging—IJ. f ntest (6) Return the dynamometer and engine controls to the idle position described in paragraph (d)(3) of this section within 60 seconds of completing the lugging mode. (7) Repeat the procedures in paragraphs (d)(3) through (6) of this section as needed to complete three valid test runs. If you fail to meet the specifications during a test run, continue to follow the specified duty cycle before starting the next test run. (8) Shut down the engine or remove the smokemeter from the exhaust stream to verify zero and linearity. Void the test if the smokemeter reports more than 2 percent opacity for the zero verification, or if the smokemeter's error for any of the linearity checks specified in paragraph (b)(2) of this section is more than 2 percent. (e) Analyze and validate the test data as follows: (1) Divide each test run into test segments. Each successive test segment starts when the preceding segment ends. Identify the test segments based on the following criteria: (i) The idle mode specified in paragraph (d)(3) of this section for the first test run starts immediately after engine preconditioning is complete. The idle mode for later test runs must start within 60 seconds after the end of the previous test run as specified in paragraph (d)(6) of this section. The idle mode ends when operator demand increases for the first acceleration event (Points A and B). (ii) The first acceleration event in paragraph (d)(4)(i) of this section ends when operator demand is set to maximum for the second acceleration event (Point C). (iii) The second acceleration event in paragraph (d)(4)(ii) of this section ends when the engine reaches 85 percent of maximum test speed, ƒ ntest, (iv) The transition period in paragraph (d)(4)(iii) of this section ends when operator demand is set to maximum (Point F). (v) The third acceleration event in paragraph (d)(4)(iv) of this section ends when engine speed reaches 95 percent of ƒ ntest (vi) The transition period in paragraph (d)(5)(i) of this section ends when engine speed first decreases to a point more than 50 r/min below ƒ ntest (vii) The lugging mode in paragraph (d)(5)(ii) of this section ends when the engine reaches intermediate speed (Point J). (2) Convert measured instantaneous values to standard opacity values, κ std, Where: κ std κ meas l std l meas Example for an engine < 40 kW: κ meas l std l meas (3) Select opacity results from corrected measurements collected across test segments as follows: (i) Divide measurements from acceleration and lugging modes into half-second intervals. Determine average opacity values during each half-second interval. (ii) Identify the 15 highest half-second values during the acceleration mode of each test run. (iii) Identify the five highest half-second values during the lugging mode of each test run. (iv) Identify the three overall highest values from paragraphs (e)(3)(ii) and (iii) of this section for each test run. (f) Determine percent opacity as follows: (1) Acceleration. (2) Lugging. (3) Peak. (g) Submit the following information in addition to what is required by § 1065.695: (1) Exhaust pipe diameter(s). (2) Measured maximum exhaust system backpressure over the entire test. (3) Most recent date for establishing that each of the reference filters from paragraph (b) of this section are NIST-traceable. (4) Measured smokemeter zero and linearity values after testing. (5) 10 Hz data from all valid test runs. (h) The following figure illustrates the dynamometer controls and engine speeds for exhaust opacity testing: Figure 1 to paragraph (h) of § 1065.1127—Schemati of Smoke Opacity Duty Cycle Accelerated Aftertreatment Aging Source: Sections 1065.1131 through 1065.1145 appear at 88 FR 4697, Jan. 24, 2023, unless otherwise noted. § 1065.1131 General provisions related to accelerated aging of compression-ignition aftertreatment for deterioration factor determination. Sections 1065.1131 through 1065.1145 specify procedures for aging compression-ignition engine aftertreatment systems in an accelerated fashion to produce an aged aftertreatment system for durability demonstration. Determine the target number of hours that represents useful life for an engine family as described in the standard setting part. The method described is a procedure for translating field data that represents a given application into an accelerated aging cycle for that specific application, as well as methods for carrying out aging using that cycle. The procedure is intended to be representative of field aging, includes exposure to elements of both thermal and chemical aging, and is designed to achieve an acceleration of aging that is ten times a dynamometer or field test (1,000 hours of accelerated aging is equivalent to 10,000 hours of standard aging). (a) Development of an application-specific accelerated aging cycle generally consists of the following steps: (1) Gathering and analysis of input field data. (2) Determination of key components for aging. (3) Determination of a thermal deactivation coefficient for each key component. (4) Determination of potential aging modes using clustering analysis. (5) Down-selection of final aging modes. (6) Incorporation of regeneration modes (if necessary). (7) Cycle generation. (8) Calculation of thermal deactivation. (9) Cycle scaling to reach thermal deactivation. (10) Determination of oil exposure rates. (11) Determination of sulfur exposure rates. (b) There are two methods for using field data to develop aging cycles, as described in § 1065.1139(b)(1) and (2). Method selection depends on the type of field data available. Method 1 directly uses field data to generate aging modes, while Method 2 uses field data to weight appropriate regulatory duty cycles that are used for emissions certification. (c) Carry out accelerated aging on either a modified engine platform or a reactor-based burner platform. The requirements for these platforms are described in § 1065.1141 for engine bench aging and § 1065.1143 for burner-based bench aging. § 1065.1133 Application selection, data gathering, and analysis. This section describes the gathering and analysis of the field generated data that is required for generation of the data cycle. Gather data for the determination of aftertreatment exposure to thermal, lubricating oil, and sulfur related aging factors. You are not required to submit this data as part of your application, but you must make this data available if we request it. (a) Field data target selection. (1) Thermal exposure. (2) Oil exposure. (3) Sulfur exposure. (b) Application data gathering. (1) When using Method 1, direct field data use, as described in § 1065.1139(b)(1), record data for exhaust flow rate and at least one representative inlet temperature for each major aftertreatment system catalyst component, such as a diesel oxidation catalyst (DOC), diesel particulate filter (DPF), or selective catalytic reduction (SCR) catalyst. If a given catalyst component has multiple substrates installed directly in sequence, it is sufficient to record only the inlet temperature for the first catalyst substrate in the sequence. It is not necessary to record separate temperatures for substrates that are “zone-coated” with multiple catalyst functions. Record a representative outlet temperature for any major catalyst component that is used to elevate the temperature of downstream components. This could be the inlet of the next major component if that would be representative. We recommend that you record engine fuel rate to assist in the determination of sulfur exposure rates, but you may use other data for this purpose. (2) When using Method 2, weighting of certification cycles, as described § 1065.1139(b)(2), record data for engine speed and engine load. Record sufficient ECM load parameters to determine a torque value that can be compared directly to engine torque as measured in the laboratory. You may optionally use ECM fuel rate measurements to determine load, but only if the same measurements can also be performed during laboratory testing on certification test cycles using sensors with comparable response characteristics. For example, you could use ECM fuel consumption rates for both field data and during laboratory tests. (i) Optionally, as an alternative to the parameters required in this paragraph (b)(2), you may use a system exhaust temperature measurement to represent load. This requires one recorded temperature that represents the aftertreatment system. We recommend that you use a temperature recorded at the outlet of the first major catalyst component. If you choose to use this option, you must use the same temperature sensor for both field and laboratory measurements. Do not compare measurements between on-engine production temperature sensors with laboratory temperature sensors. (ii) Optionally, as an alternative to the parameters required in this paragraph (b)(2), you may use exhaust flow and temperature measurements recorded in the field to support Method 2 calculations. Only one recorded temperature that represents the aftertreatment system is needed in this case. We recommend that you use a temperature recorded at the outlet of the first major catalyst component. Do not compare measurements between on-engine production temperature sensors with laboratory temperature sensors. (3) If you have an aftertreatment system which involves periodic regeneration events where the temperature is raised above levels observed during normal operation, you must record data to characterize each such event. Data must be recorded at a frequency of at least 1 Hz, and you must record the exhaust flow rate and inlet temperature of each key catalyst component that will experience elevated temperatures during the regeneration. In addition, record a flag or variable that can be used to determine the beginning and end of a regeneration event. You must record at least three such events to allow determination of the average regeneration profile. If you have multiple types of regeneration events which influence different catalyst components in the system, you must record this data for each type of event separately. Use good engineering judgment to determine the average duration of each type of regeneration event, and the average interval of time between successive regeneration events of that type. You may use the data recorded for this cycle determination, or any other representative data to determine average regeneration duration or regeneration interval. These values may be determined from the analysis used to determine emission adjustments to account for infrequent regeneration of aftertreatment devices in § 1065.680. § 1065.1135 Determination of key aftertreatment system components. Most compression-ignition engine aftertreatment systems contain multiple catalysts, each with their own aging characteristics. However, in the accelerated aging protocol the system will be aged as a whole. Therefore, it is necessary to determine which catalyst components are the key components that will be used for deriving and scaling the aging cycle. (a) The primary aging catalyst in an aftertreatment system is the catalyst that is directly responsible for the majority of NO X (b) The secondary aging catalyst in an aftertreatment system is the catalyst that is intended to either alter exhaust characteristics or generate elevated temperature upstream of the primary catalyst. An example of a secondary component catalyst would be a DOC placed upstream of an SCR catalyst, with or without a DPF in between. § 1065.1137 Determination of thermal reactivity coefficient. This section describes the method for determining the thermal reactivity coefficient(s) used for thermal heat load calculation in the accelerated aging protocol. (a) The calculations for thermal degradation are based on the use of an Arrhenius rate law function to model cumulative thermal degradation due to heat exposure. Under this model, the thermal aging rate constant, k, Eq. 1065.1137-1 Where: A E a R T (b) The process of determining E a (1) Copper-based zeolite SCR. 3 X (i) The ratio between the storage capacity of the two sites, with more active site being in the denominator. (ii) Storage capacity of the more active site. (2) Iron-based zeolite SCR. 3 (3) Vanadium SCR. 3 3 X X (4) Zone-coated zeolite SCR. 3 (5) Diesel oxidation catalysts. 2 X (c)(1) Use good engineering judgment to select at least three different temperatures to complete the degradation experiments. We recommend selecting these temperatures to accelerate thermal deactivation such that measurable changes in the aging metric can be observed at multiple time points over the course of no more than 64 hours. Avoid temperatures that are too high to prevent rapid catalyst failure by a mechanism that does not represent normal aging. An example of temperatures to run the degradation experiment at for a small-pore copper zeolite SCR catalyst is 600 °C, 650 °C, and 725 °C. (2) For each aging temperature selected, perform testing to assess the aging metric at different times. These time intervals do not need to be evenly spaced and it is typical to complete these experiments using increasing time intervals ( e.g., (i) For SCR-based NH 3 3 i.e., 3 (ii) For DOC formulations, conduct an NO Reverse Light Off (RLO) to quantify oxidation conversion efficiency of NO to NO 2 i.e., (d) Generate a fit of the deactivation data generated in paragraph (b) of this section at each temperature. (1) Copper-based zeolite SCR. 3 3 (i) We recommend that you use the Temkin adsorption model to quantify the NH 3 et al, et al, Eq. 1065.1137-2 Where: k e E a (1−αθ) /RT E a α θ R T (A) Use Eq. 1065.1137-2 to express the NH 3 Eq. 1065.1137-3 Where: N 1 3 A 1 E a,T1 N 2 3 A 2 E a,T2 (B) Optimize E a,T1 α 1 A 1 E a,T2 α 2 A 2 3 3 N 1 N 2 (ii) Use one of the following modeling approaches to derive the thermal reactivity coefficient, E a,D E a,D (A) General Power Law Expression (GPLE). Eq. 1065.1137-4 Where: k D Eq. 1065.1137-5 A E a,D R T Ω = N 2 N 1 N 2 i.e., t Ω eq m ( 1 Eq. 1065.1137-6 Where: Ω 0 N 2 N 1 N 2 A E a,D R T t ( 2 E a,D A D SSE Global E a,D A D Eq. 1065.1137-7 Where: n i SEE T T Eq. 1065.1137-8 Where: n i Ω Exp T Ω model T (B) Arrhenius approach. k D Ω ( 1 Eq. 1065.1137-9 Where: Ω = N 2 1 2 Ω Ω i.e., Ω t (Eq. 1065.1137-5) A E a,D R T ( 2 Ω t k D k D E a k D T E a,D m deactivation E a,D m deactivation R Eq. 1065.1137-10 Where: m deactivation k D T R (2) Iron-based zeolite or vanadium SCR. 3 3 m Eq. 1065.1137-11 Where: Ω 3 i.e., t (Eq. 1065.1137-5) A E a,D R T t Ω eq m (i) Solve Eq. 1065.1137-10 for Ω to yield the following expression: Eq. 1065.1137-12 Where: Ω 0 3 A = E a,D = R T t m (ii) Global fitting is to be used to solve for E a,D A D SSE Global m E a,D A D m SSE Global m (3) Zone-coated zeolite SCR. E a,D E a,D (4) Diesel oxidation catalyst. Eq. 1065.1137-13 Where: v X 2 V Eq. 1065.1137-14 A D E a,D = R T (ii) For a diesel oxidation catalyst, the preexponential term A D k D, k D A D Eq. 1065.1137-15 Where: SV X 2 E a,D T X R (iii) Process all NO to NO 2 X, T t A D A D i.e., t (A) Use the GPLE to fit the NO to NO 2 X, Eq. 1065.1137-16 Where: Ω = aging metric for diesel oxidation catalysts. (Eq. 1065.1137-14) R T t Ω eq m (B) Solve Eq. 1065.1137-12 for to yield the following expression: Eq. 1065.1137-17 Where: Ω eq X, A = E a,D = R T t m (iv) Use global fitting to solve for E a,D A SSE Global m, E a,D A m, SSE Global m [89 FR 29827, Apr. 22, 2024] § 1065.1139 Aging cycle generation. Generation of the accelerated aging cycle for a given application involves analysis of the field data to determine a set of aging modes that will represent that field operation. There are two methods of cycle generation, each of which is described separately below. Method 1 involves the direct application of field data and is used when the recorded data includes sufficient exhaust flow and temperature data to allow for determination of aging conditions directly from the field data set and must be available for all of the key components. Method 2 is meant to be used when insufficient flow and temperature data is available from the field data. In Method 2, the field data is used to weight a set of modes derived from the laboratory certification cycles for a given application. These weighted modes are then combined with laboratory recorded flow and temperatures on the certification cycles to derive aging modes. There are two different cases to consider for aging cycle generation, depending on whether or not a given aftertreatment system incorporates the use of a periodic regeneration event. For the purposes of this section, a “regeneration” is any event where the operating temperature of some part of the aftertreatment system is raised beyond levels that are observed during normal (non-regeneration) operation. The analysis of regeneration data is considered separately from normal operating data. (a) Cycle generation process overview. (b) Analysis of normal (non-regeneration) operating data. (1) Method 1—Direct clustering. (i) The primary method for determining modes from a field data set involves the use of k-means clustering. K-means clustering is a method where a series of observations is partitioned into set of clusters of “similar” data points, where every observation is a member of a cluster with the nearest mean, which is referred to as the centroid of that cluster. The number of clusters is a parameter of the analysis, and the k-means algorithm generally seeks an optimal number of clusters to minimize the least-squares distance of all points to their respective centroids. There are a number of different commercially available software programs to perform k-means clustering, as well as freely available algorithm codes. K-means clustering can arrive at many different solutions, and we are providing the following guidance to help select the optimal solution for use in accelerated aging cycle generation. The process involves analyzing the data multiple time using an increasing number of clusters for each analysis. Use at least 5 clusters, and we recommend developing solutions for the range between 5 and 8 clusters, although you may use more if desired. Each cluster is a potential aging mode with a temperature and flow rate defined by the centroid. More clusters result in more aging modes, although this number may be reduced later via model consolidation. (ii) The cubic clustering criteria (CCC) is a metric calculated for each solution having a different number of clusters. The computation of CCC is complex and described in more detail in the following reference. The CCC computation is normally available as one of the metrics in commercially available software packages that can be used for k-means clustering. The optimal solution is typically the one with the number of clusters corresponding to the highest CCC. (iii) Check each solution, starting with the one with the highest CCC to determine if it satisfies the following requirements: (A) No more than one cluster contains fewer than 3% of the data points. (B) The temperature ratio between the centroid with the maximum temperature and the centroid with the minimum temperature is at least 1.6 for clusters containing more than 3% of the data points. (C) If that solution does not satisfy these requirements move to the solution with the next highest CCC. (iv) The process described in paragraph (c)(1)(iii) of this section generally works well for most data sets, but if you have difficulty with the CCC metric in a particular data set, use good engineering judgment to leverage additional criteria to help the down-selection process. Examples of alternate clustering metrics include a Davies-Bouldin Index (optimizing on the minimum value) or a Calinski-Harabasz Index (optimize on the maximum value). (v) The initial candidate mode conditions are temperature and flow rate combinations that are the centroids for each cluster from the analysis in paragraph (c)(1)(iii) of this section. As part of the analysis, you must also determine the 10th percentile and 90th percentile temperatures for each cluster. These additional values may be needed later for the cycle heat load tuning process described in § 1065.1143. (vi) The mode weight factor for a given cluster is the fraction data points contained within that cluster. (2) Method 2—Cluster-based weighting of certification cycle modes. (i) Perform k-means clustering is described in § 1065.1133(b)(1) but using data sets containing the two parameters recorded in the field data sets. For example, you might use speed and torque, as recorded both in the field and the laboratory for Method 2 clustering. (ii) Determine the fraction of points from each of the regulatory laboratory duty-cycles that are within each cluster, in addition to the overall fraction of points from the entire data set. (iii) For each cycle, calculate a square sum error, SSE, Where: i N Cycle prob i, RefData prob i, (iv) For each cycle, calculate a dissimilarity index as follows: Where: SSE N (v) If you have more than one regulatory duty cycle, weight the regulatory cycles. (A) Determine the weighting factors for a given regulatory cycle, w i Where: d i i. d j j. (B) For example, for three duty cycles, calculate w 1 (C) Calculate subsequent w i 1 (D) Calculate the sum of the weighting factors to verify that they are equal to one. Where: n (vi) For each regulatory cycle determine the average exhaust flow and the average inlet temperature for each key catalyst. Determine the 25th and 90th percentile inlet temperatures for the primary catalyst and the respective associated exhaust flow rate for each data point. (vii) Use the cycle weights from paragraph (b)(2)(v) of this section and the mode conditions from paragraph (b)(2)(vi) of this section to generate a set of candidate aging modes by multiplying the cycle weight factor, w [cycle] (viii) If you have only one regulatory cycle for your application, use the cycle modes and weighting factors as they are given in the standard setting part. (3) Determination of mode total durations. (c) Mode consolidation. (1) Consolidate any two or more modes which have a target temperature within 10 °C into a single mode. If you choose to do this, the target temperature of the single consolidated mode is the temperature associated with the highest weight factor mode before consolidation. If the modes being consolidated all have weighting factors within 0.05 of each other, use the highest temperature among the modes. (2) Use the highest exhaust flow target among the modes being combined as the target exhaust flow for new consolidate mode. (3) Use the combined sum of the weighting factors for all modes being consolidate as the weighting factor for the new consolidated mode. Similarly, the total duration of the new consolidated mode is the sum of the durations of the modes being consolidated. (d) Analysis of regeneration data. (1) The total number of regenerations that will be run during the accelerated aging process will be the same as the total number of regenerations over useful life. Calculate this number by dividing the total number of useful life hours by the interval between regenerations as determined in § 1065.1133(b)(3). (2) Use the 1 Hz regeneration data to determine an appropriate regeneration profile. The recorded regeneration event begins when the engine indicates it has started regeneration using the recorded regeneration indicator and ends when the aftertreatment has returned back to the normal operating temperature after the flag indicates the regeneration is complete. (3) For each recorded regeneration, calculate the cumulative deactivation, D t (4) If you have a large number of recorded regenerations in your data set, select a regeneration event with a cumulative deactivation representing the 75th percentile of the distribution of heat loads in your recorded data set. If you have a smaller number of recorded regenerations, such that you cannot clearly identify the real distribution, select the recorded regeneration with the highest recorded cumulative deactivation. (5) This regeneration event will be used as the regeneration profile for that type of event during aging. The profile should include the entire event, include the temperature ramp and cool-down period. (6) The regeneration must be conducted in the same manner as it is run in the field. For instance, if the regeneration temperature is generated from an exothermic reaction by injecting fuel in front of a DOC, this methodology should also be used during bench aging. (7) If part of the system is at a lower temperature during regeneration because it is upstream of the temperature generating component, the set the target temperature for the aftertreatment system inlet to be equivalent to the system inlet temperature used during the highest duration non-regeneration mode, or 350 °C, whichever is lower. (e) Heat load calculation and tuning for systems that have regeneration events. (1) The deactivation for a given catalyst is calculated for each time step as follows: Where: D i i. E a R T std T (2) Calculate the cumulative deactivation, D t N Where: i N D i (3) Calculate the cumulative deactivation, D t (i) First calculate D t (ii) Divide the calculate field D t (iii) Multiply the hourly D t D t,field-normi (iv) Multiply the total number of regenerations for full useful life by the cumulative deactivation D t D t,field-regen (v) The total target cumulative deactivation for the field data, D t,field D t,field-norm i D t,field-regen (4) Calculate the cumulative deactivation for the candidate aging cycle generated under paragraphs (c) and (d) of this section as follows: (i) Using the modes and mode durations for normal operation generated in paragraph (c) of this section, calculate the cumulative deactivation, D t,cycle-norm (ii) The total cumulative deactivation for the candidate aging cycle, D t D t,cycle-norm D t,field-regen (5) If D t,cycle D t,field (6) If D t,cycle D t,field D t,cycle D t,field (i) Increase the duration of the stable portion of the regeneration profile, which is defined as the portion of the regeneration profile where the temperature has completed ramping and is being controlled to a stationary target temperature. Note that this will increase the number of hours of regeneration time. You must compensate for this by decreasing the total number of normal operation (non-regeneration) hours in the cycle. Recalculate the duration of all the normal operation modes. You may not increase the duration of the stable portion of the regeneration profile by more than a factor of 2. If you reach this limit and you still do not meet the criteria in paragraph (e)(5) of this section, proceed to the next step. (ii) Increase the target temperature of the stable portion of the regeneration profile by the amount necessary to reach the target criteria. You may not increase this temperature higher than the temperature observed in the regeneration profile with the highest D t (iii) Increase the target temperature of the highest temperature normal operation mode. You may not increase this temperature above the 90th percentile determined in paragraph (b)(1)(v) of this section for Method 1, or above the maximum temperature for the regulatory cycle from which the mode was derived for Method 2. If you reach this limit and you still do not meet the criteria in paragraph (e)(5) of this section, you may repeat this step using the next highest temperature mode, until you reach the target, or all modes have been adjusted. (iv) If you are unable to reach the target deactivation by following paragraphs (e)(6)(i) through (iii) of this section, use good engineering judgment to increase the number of regenerations to meet the criteria in paragraph (e)(5) of this section. Note that this will increase the total regeneration hours, therefore you must decrease the number of normal operation hours and re-calculate mode durations for the normal operation modes. (v) If you are not able to achieve the target D t,field (f) Heat load calculation and tuning for systems that do not have regeneration events. D t,field D t,cycle D t,cycle D t,field (1) Increase the temperature of the highest temperature mode. Use good engineering judgment to ensure that this temperature does not exceed the limits of the catalyst in a way that might cause rapid deactivation or failure via a mechanism that is not considered normal degradation. (2) Increase the duration of the highest temperature mode and decrease the duration of the other modes in proportion. You may not increase the duration highest temperature mode by more than a factor of 2. (3) If you are not able to achieve the target D t,field (g) Final aging cycle assembly. (1) Cycle assembly with infrequent regenerations. (i) If you have multiple types of infrequent regenerations, arrange the more frequent regenerations such that they are spaced evenly throughout the cycle. (ii) Determine the length of the normal (non-regeneration) part of the cycle by subtracting the regeneration duration, including any regeneration extension determined as part of cycle tuning from paragraph (e) of this section, from the total cycle duration. If you have multiple types of regeneration, then the combined total duration of regeneration events performed in the cycle must be subtracted from the total. For example, if you have one type of regeneration that is performed for 30 minutes every 30 cycle hours, and a second type that is performed for 30 minutes every 10 cycle hours (such that 3 of these secondary events will happen during each cycle), then you would subtract a total of 2 hours of regeneration time from the total cycle duration considering all 4 of these events. (iii) Divide the duration of the normal part of the cycle into modes based on the final weighting factors determined in paragraph (c) of this section following any mode consolidation. (iv) Place the mode with the lowest temperature first, then move to the highest temperature mode, followed by the next lowest temperature mode, and then the next highest mode, continuing in this alternating pattern until all modes are included. (v) Transition between normal modes within (60 to 300) seconds. The transition period is considered complete when you are within ±5 °C of the target temperature for the primary key component. Transitions may follow any pattern of flow and temperature to reach this target within the required 300 seconds. (vi) For normal modes longer than 30 minutes, you may count the transition time as time in mode. Account for the transition time for modes shorter than 30 minutes by shortening the duration of the longest mode by an equivalent amount of time. (vii) If the shortest normal operating mode is longer than 60 minutes, you must divide the normal cycle into shorter sub-cycles with the same pattern in paragraph (g)(1)(iii) of this section, but with shorter durations, so that the pattern repeats two or more times. You must divide the cycle into sub-cycles until the duration of the shortest mode in each sub-cycle is no longer than 30 minutes. No mode may have a duration shorter than 15 minutes, not including transition time. (viii) If a regeneration event is scheduled to occur during a normal mode, shift the start of regeneration to the end of the nearest normal mode. (2) Cycle assembly without infrequent regenerations. (i) Assign a duration of 15 minutes to the mode with the lowest weight factor. Calculate the duration of the remaining modes in proportion to the final weight factors after mode durations have been adjusted during heat load tuning in paragraph (f) of this section. (ii) Place the mode with the lowest temperature first, then move to the highest temperature mode, followed by the next lowest temperature mode, and then the next highest mode, continuing in this alternating pattern until all modes are included. (iii) Transition between normal modes within (60 to 300) seconds. The transition period is considered complete when you are within ±5 °C of the target temperature for the primary key component. Transitions may follow any pattern of flow and temperature to reach this target within the required 300 seconds. (iv) For normal modes longer than 30 minutes, you may count the transition time as time in mode. Account for the transition time for modes shorter than 30 minutes by shortening the duration of the longest mode by an equivalent amount of time. (v) This cycle will be repeated the number of times necessary to reach the target aging duration. (h) Chemical exposure targets. (1) Oil exposure targets. i.e., (2) Fuel sulfur exposure targets. (i) For an engine-based aging stand, if you perform accelerated sulfur exposure by additizing engine fuel to a higher sulfur level, determine the accelerated aging target additized fuel sulfur mass fraction, w S, Eq. 1065.1139-9 Where: m fuel,field m fuel,cycle m Sfuel,ref S acc,rate Example: m fuel,field m fuel,cycle m Sfuel,ref S acc,rate (ii) If you use gaseous SO 2 2 x SO2,target Eq. 1065.1139-10 Where: m fuel,field m exhaust,cycle x Sfuel,ref S acc,rate M exh M S Example: m fuel,field m exhaust,cycle x Sfuel,ref S acc,rate M exh M S (iii) You may choose to turn off gaseous sulfur injection during infrequent regeneration modes, but if you do you must increase the target SO 2 [79 FR 23820, Apr. 28, 2014, as amended at 89 FR 29829, Apr. 22, 2024] § 1065.1141 Facility requirements for engine-based aging stands. An engine-based accelerated aging platform is built around the use of a compression-ignition engine for generation of heat and flow. You are not required to use the same engine as the target application that is being aged. You may use any compression-ignition engine as a bench aging engine, and the engine may be modified as needed to support meeting the aging procedure requirements. You may use the same bench aging engine for deterioration factor determination from multiple engine families. The engine must be capable of reaching the combination of temperature, flow, NO X (a) Use good engineering judgment to incorporate a means of controlling temperature independent of the engine. An example of such a temperature control would be an air-to-air heat exchanger. The temperature control system must be designed to prevent condensation in the exhaust upstream of the aftertreatment system. This independent temperature control is necessary to provide the flexibility required to reach temperature, flow, oil consumption targets, and NO X (b) Use good engineering judgment to modify the engine to increase oil consumption rates to levels required for accelerated aging. These increased oil consumption levels must be sufficient to reach the bulk pathway exposure targets determined in § 1065.1139(h). A combination of engine modifications and careful operating mode selection will be used to reach the final bulk pathway oil exposure target on a cycle average. You must modify the engine in a fashion that will increase oil consumption in a manner such that the oil consumption is still generally representative of oil passing the piston rings into the cylinder. Use good engineering judgment to break in the modified engine to stabilize oil consumption rates. We recommend the following methods of modification (in order of preference): (1) Install the second compression ring inverted (upside down) on one or more of the cylinders of the bench aging engine. This is most effective on rings that feature a sloped design to promote oil control when normally installed. (2) If the approach in paragraph (b)(1) of this section is insufficient to reach the targets, modify the oil control rings in one or more cylinders to reduce the spring tension on the oil control ring. It should be noted that this is likely to be an iterative process until the correct modification has been determined. (3) If the approach in paragraph (b)(2) of this section is insufficient to reach the targets, modify the oil control rings in one or more cylinders to create small notches or gaps (usually no more than 2 per cylinder) in the top portion of the oil control rings that contact the cylinder liner (care must be taken to avoid compromising the structural integrity of the ring itself). (c) We recommend that the engine-aging stand include a constant volume oil system with a sufficiently large oil reservoir to avoid oil “top-offs” between oil change intervals. (d) If the engine-aging stand will be used for aging of systems that perform infrequent regenerations, the aging stand must incorporate a means of increasing temperature representative of the target application. For example, if the target application increases temperature for regeneration by introducing fuel into the exhaust upstream of an oxidation catalyst, the aging stand must incorporate a similar method of introducing fuel into the exhaust. (e) If the engine-aging stand will be used for aging systems that incorporate SCR-based NO X (f) Use good engineering judgment to incorporate a means of monitoring oil consumption on a periodic basis. You may use a periodic drain and weigh approach to quantify oil consumption. We recommend that you incorporate a method of continuous oil consumption monitoring, but you must validate that method with periodic draining and weighing of the engine oil. You must validate that the aging stand reaches oil consumption targets prior to the start of aging. You must verify oil consumption during aging prior to each emission testing point, and at each oil change interval. Validate or verify oil consumption over a running period of at least 72 hours to obtain a valid measurement. If you do not include the constant volume oil system recommended in paragraph (c) of this section, you must account for all oil additions. (g) Use good engin

eering judgment to establish an oil change interval that allows you to maintain relatively stable oil consumption rates over the aging process. Note that this interval may be shorter than the normal recommended interval for the engine due to the modifications that have been made. (h) If the engine-aging stand will be used for aging of systems that incorporate a diesel particulate filter (DPF), we recommend you perform secondary tracking of oil exposure by using clean (soot free) DPF weights to track ash loading and compare this mass of ash to the amount predicted using the measured oil consumption mass and the oil ash concentration. The mass of ash found by DPF weight should fall within (55 to 70)% of the of mass predicted from oil consumption measurements. (i) Incorporate a means of introducing lubricating oil into the engine fuel to enable the volatile pathway of oil exposure. You must introduce sufficient oil to reach the volatile pathway oil exposure targets determined in paragraph (h) of this section. You must measure the rate of volatile pathway oil introduction on a continuous basis. (j) If you perform sulfur acceleration by increasing the sulfur level of the engine fuel, you must meet the target sulfur level within ±5 ppmw. Verify the sulfur level of the fuel prior to starting aging, or whenever a new batch of aging fuel is acquired. (k) If you use gaseous SO 2 2 2 2 [79 FR 23820, Apr. 28, 2014, as amended at 89 FR 29831, Apr. 22, 2024] § 1065.1143 Requirements for burner-based aging stands. A burner-based aging platform is built using a fuel-fired burner as the primary heat generation mechanism. The burner must utilize diesel fuel and it must produce a lean exhaust gas mixture. You must configure the burner system to be capable of controlling temperature, exhaust flow rate, NO X (a) Directly measure the exhaust flow through the aftertreatment system being aged. (b) Ensure transient response of the system is sufficient to meet the cycle transition time targets for all parameters. (c) Incorporate a means of oxygen and water control such that the burner system is able to generate oxygen and water levels representative of compression-ignition engine exhaust. (d) Incorporate a means of oil introduction for the bulk pathway. You must implement a method that introduces lubricating oil in a region of the burner that does not result in complete combustion of the oil, but at the same time is hot enough to oxidize oil and oil additives in a manner similar to what occurs when oil enters the cylinder of an engine past the piston rings. Care must be taken to ensure the oil is properly atomized and mixed into the post-combustion burner gases before they have cooled to normal exhaust temperatures, to insure proper digestion and oxidation of the oil constituents. You must measure the bulk pathway oil injection rate on a continuous basis. You must validate that this method produces representative oil products using the secondary method in § 1065.1141(h) regardless of whether you will use the burner-based aging stand to age systems which include a DPF. Use good engineering judgment to select a DPF for the initial validation of the system. Perform this validation when the burner-based aging stand is first commissioned or if any system modifications are made that affect the oil consumption introduction method. We also recommend that you examine ash distribution on the validation DPF in comparison to a representative engine aged DPF. (e) Incorporate a means of introducing lubricating oil into the burner fuel to enable the volatile pathway of oil exposure. You must introduce sufficient oil to reach the volatile pathway oil exposure targets determined in § 1065.1139(h). You must measure the rate of volatile pathway oil introduction on a continuous basis. (f) If the burner-based aging stand will be used for aging of systems that perform infrequent regenerations, the aging stand must incorporate a means of increasing temperature representative of the target application. For example, if the target application increases temperature for regeneration by introducing fuel into the exhaust upstream of an oxidation catalyst, the aging stand must incorporate a similar method of introducing fuel into the exhaust. (g) If the burner-based aging stand will be used for aging of systems that incorporate SCR-based NO X (h) If the burner-based aging stand will be used for aging of systems that incorporate a diesel particulate filter (DPF), we recommend you perform secondary tracking of oil exposure by using clean (soot free) DPF weights to track ash loading and compare this mass of ash to the amount predicted using the measured oil consumption mass and the oil ash concentration. The mass of ash found by DPF weight should fall within (55 to 70)% of the of mass predicted from oil consumption measurements. (i) You must incorporate a means to introduce the gaseous SO 2 2 2 § 1065.1145 Execution of accelerated aging, cycle tracking, and cycle validation criteria. The aging cycle generally consists first of practice runs to validate and tune the final cycle, followed by the actual running of the repeat cycles needed to accumulate field equivalent hours to reach full useful life. During the course of the aging run, various aging parameters are tracked to allow verification of proper cycle execution, as well as to allow for correction of the aging parameters to stay within the target limits. (a) Preliminary cycle validation runs. (1) Engine-based platform. Initial cycle development. X X X X X (ii) Final cycle validation. D t D t,cycle D t,cycle, D t D t (2) Burner-based platform. Cycle development. X X (ii) Final cycle validation. D t D t,cycle D t,cycle, D t D t (b) Aftertreatment break in. (c) Initial emission testing. (d) Accelerated aging. (e) QA tracking and validation. (1) Thermal load tracking. D t. D t D t (2) Oil consumption tracking. (i) Changing engine oil. (ii) Secondary oil consumption validation. (iii) Sulfur tracking. 2 2 (f) Emission testing at intermediate and final test points. [79 FR 23820, Apr. 28, 2014, as amended at 89 FR 29831, Apr. 22, 2024]

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