40 CFR Part 1036 — Control of Emissions from New and In-Use Heavy-Duty Highway Engines

PART 1036—CONTROL OF EMISSIONS FROM NEW AND IN-USE HEAVY-DUTY HIGHWAY ENGINES Authority: 42 U.S.C. 7401—7671q. Source: 88 FR 4487, Jan. 24, 2023, unless otherwise noted. Subpart A—Overview and Applicability § 1036.1 Applicability. (a) Except as specified in § 1036.5, the provisions of this part apply for engines that will be installed in heavy-duty vehicles (including glider vehicles). Heavy-duty engines produced before December 20, 2026 are subject to exhaust emission standards for NO X (1) The provisions of §§ 1036.115, 1036.501(d), and 1036.601 apply. (2) 40 CFR parts 85 and 86 may specify that certain provisions in this part apply. (3) This part describes how several individual provisions are optional or mandatory before model year 2027. For example, § 1036.150(a) describes how you may generate emission credits by meeting the standards of this part before model year 2027. (b) The provisions of this part also apply for fuel conversions of all engines described in paragraph (a) of this section as described in 40 CFR 85.502. (c) Gas turbine heavy-duty engines and other heavy-duty engines not meeting the definition of compression-ignition spark-ignition (d) For the purpose of applying the provisions of this part, engines include all emission-related components and any components or systems that should be identified in your application for certification, such as hybrid components for engines that are certified as hybrid engines or hybrid powertrains. (e) This part establishes criteria pollutant standards as described in § 1036.101. This part does not establish standards for CO 2 2 [88 FR 4487, Jan. 24, 2023, as amended at 91 FR 7775, Feb. 18, 2026] § 1036.2 Compliance responsibility. The regulations in this part contain provisions that affect both engine manufacturers and others. However, the requirements of this part are generally addressed to the engine manufacturer(s). The term “you” generally means the engine manufacturer(s), especially for issues related to certification. Additional requirements and prohibitions apply to other persons as specified in subpart G of this part and 40 CFR part 1068. § 1036.5 Excluded engines. (a) The provisions of this part do not apply to engines used in medium-duty passenger vehicles or other heavy-duty vehicles that are subject to regulation under 40 CFR part 86, subpart S, except as specified in 40 CFR part 86, subpart S. For example, this exclusion applies for engines used in incomplete vehicles or high-GCWR vehicles certified to vehicle-based standards as described in 40 CFR 86.1801-12. (b) An engine installed in a heavy-duty vehicle that is not used to propel the vehicle is not a heavy-duty engine. The provisions of this part therefore do not apply to these engines. Note that engines used to indirectly propel the vehicle (such as electrical generator engines that provide power to batteries for propulsion) are subject to this part. See 40 CFR part 1039, 1048, or 1054 for other requirements that apply for these auxiliary engines. See 40 CFR part 1037 for requirements that may apply for vehicles using these engines, such as the evaporative and refueling emission requirements of 40 CFR 1037.103. (c) The provisions of this part do not apply to aircraft or aircraft engines. Standards apply separately to certain aircraft engines, as described in 40 CFR part 87. (d) The provisions of this part do not apply to engines that are not internal combustion engines. For example, the provisions of this part generally do not apply to fuel cells. Note that gas turbine engines are internal combustion engines. [88 FR 4487, Jan. 24, 2023, as amended at 91 FR 7775, Feb. 18, 2026] § 1036.10 Organization of this part. This part is divided into the following subparts: (a) Subpart A of this part defines the applicability of this part and gives an overview of regulatory requirements. (b) Subpart B of this part describes the emission standards and other requirements that must be met to certify engines under this part. Note that § 1036.150 describes certain interim requirements and compliance provisions that apply only for a limited time. (c) Subpart C of this part describes how to apply for a certificate of conformity. (d) Subpart D of this part addresses testing of production engines. (e) Subpart E of this part describes provisions for testing in-use engines. (f) Subpart F of this part describes how to test your engines (including references to other parts of the Code of Federal Regulations). (g) Subpart G of this part describes requirements, prohibitions, and other provisions that apply to engine manufacturers, vehicle manufacturers, owners, operators, rebuilders, and all others. (h) Subpart H of this part describes how you may generate and use emission credits to certify your engines. (i) Subpart I of this part contains definitions and other reference information. § 1036.15 Other applicable regulations. (a) Parts 85 and 86 of this chapter describe additional provisions that apply to engines that are subject to this part. See § 1036.601. (b) Part 1037 of this chapter describes emission standards and other requirements for heavy-duty vehicles, whether or not they use engines certified under this part. (c) Part 1065 of this chapter describes procedures and equipment specifications for testing engines to measure exhaust emissions. Subpart F of this part describes how to apply the provisions of part 1065 of this chapter to determine whether engines meet the exhaust emission standards in this part. (d) The requirements and prohibitions of part 1068 of this chapter apply as specified in § 1036.601 to everyone, including anyone who manufactures, imports, installs, owns, operates, or rebuilds any of the engines subject to this part, or vehicles containing these engines. See § 1036.601 to determine how to apply the part 1068 regulations for heavy-duty engines. The issues addressed by these provisions include these seven areas: (1) Prohibited acts and penalties for engine manufacturers, vehicle manufacturers, and others. (2) Rebuilding and other aftermarket changes. (3) Exclusions and exemptions for certain engines. (4) Importing engines. (5) Selective enforcement audits of your production. (6) Recall. (7) Procedures for hearings. (e) Other parts of this chapter apply if referenced in this part. [88 FR 4487, Jan. 24, 2023, as amended at 91 FR 7775, Feb. 18, 2026] § 1036.30 Submission of information. Unless we specify otherwise, send all reports and requests for approval to the Designated Compliance Officer (see § 1036.801). See § 1036.825 for additional reporting and recordkeeping provisions. Subpart B—Emission Standards and Related Requirements § 1036.101 Overview of exhaust emission standards. (a) You must show that engines meet the criteria pollutant standards for NO X (b) You may optionally demonstrate compliance with the emission standards of this part by testing hybrid powertrains, rather than testing the engine alone. Except as specified, provisions of this part that reference engines apply equally to hybrid powertrains. [89 FR 29738, Apr. 22, 2024, as amended at 91 FR 7775, Feb. 18, 2026] § 1036.104 Criteria pollutant emission standards—NO X This section describes the applicable NO X (a) Emission standards. (1) The following emission standards apply for Light HDE, Medium HDE, and Heavy HDE over the FTP, SET, and LLC duty cycles using the test procedures described in subpart F of this part: Table 1 to Paragraph ( a Duty cycle NO X HC mg/hp·hr PM mg/hp·hr CO g/hp·hr SET and FTP 35 60 5 6.0 LLC 50 140 5 6.0 (2) The following emission standards apply for Spark-ignition HDE over the FTP and SET duty cycles using the test procedures described in subpart F of this part: Table 2 to Paragraph ( a Duty cycle NO X HC mg/hp·hr PM mg/hp·hr CO g/hp·hr SET 35 60 5 14.4 FTP 35 60 5 6.0 (3) The following off-cycle emission standards apply for Light HDE, Medium HDE, and Heavy HDE using the procedures specified in § 1036.530, as follows: Table 3 to Paragraph ( a Off-cycle Bin NO X Temperature adjustment a HC mg/hp·hr PM mg/hp·hr CO g/hp·hr Bin 1 10.0 g/hr (25.0− T amb Bin 2 58 mg/hp·hr (25.0− T amb 120 7.5 9 a T amb X T amb X X X (b) Clean Idle. X X (c) Averaging, banking, and trading. X (1) To generate or use emission credits, you must specify a family emission limit for each engine family. Declare the family emission limit corresponding to full useful life for engine operation over the FTP duty cycle, FEL FTP FTP (2) The following NO X FTP (i) 65 mg/hp·hr for model years 2027 through 2030. (ii) 50 mg/hp·hr for model year 2031 and later. (3) Calculate the NO X FEL [cycle]NO X Where: Std [cycle]NO X X FEL FTPNO X X Std FTPNO X X Example for model year 2029 Medium HDE for the SET: Std SETNO X FEL FTP Std FTPNO X FEL SETNO X (4) The family emission limits you select under this paragraph (c) serve as the emission standards for compliance testing instead of the standards specified in this section. (d) Fuel types. (1) Alcohol-fueled engines: NMHCE emissions. (2) Gaseous-fueled engines: NMNEHC emissions. (3) Other engines: NMHC emissions. (e) Useful life. Table 4 to Paragraph ( e Primary intended service class Model year 2026 and earlier Model year 2027 and later Miles Years Hours Miles Years Hours Spark-ignition HDE 110,000 10 200,000 15 10,000 Light HDE 110,000 10 270,000 15 13,000 Medium HDE 185,000 10 350,000 12 17,000 Heavy HDE 435,000 10 22,000 650,000 11 32,000 (f) Applicability for testing. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29738, Apr. 22, 2024] § 1036.110 Diagnostic controls. Onboard diagnostic (OBD) systems must generally detect malfunctions in the emission control system, store trouble codes corresponding to detected malfunctions, and alert operators appropriately. Starting in model year 2027, new engines must have OBD systems as described in this section. You may optionally comply with any or all of the requirements of this section instead of 40 CFR 86.010-18 in earlier model years. (a) The requirements of this section apply for engines certified under this part, except in the following circumstances: (1) Heavy-duty engines intended to be installed in heavy-duty vehicles at or below 14,000 pounds GVWR must meet the OBD requirements in 40 CFR 86.1806-27. Note that 40 CFR 86.1806-27 allows for using later versions of specified OBD requirements from the California Air Resources Board, which includes meeting the 2019 heavy-duty OBD requirements adopted for California and updated emission thresholds as described in this section. (2) Heavy-duty spark-ignition engines intended to be installed in heavy-duty vehicles above 14,000 pounds GVWR may instead meet the OBD requirements in 40 CFR 86.1806-27 if the same engines are also installed in vehicles certified under 40 CFR part 86, subpart S, where both sets of vehicles share similar emission controls. (b) Engines must comply with the 2019 heavy-duty OBD requirements adopted for California as described in this paragraph (b). California's 2019 heavy-duty OBD requirements are part of 13 CCR 1968.2, 1968.5, 1971.1, and 1971.5 (incorporated by reference, see § 1036.810). We may approve your request to certify an OBD system meeting alternative specifications if you submit information as needed to demonstrate that it meets the intent of this section. For example, we may approve your request for a system that meets a later version of California's OBD requirements if you demonstrate that it meets the intent of this section; the demonstration must include identification of any approved deficiencies and your plans to resolve such deficiencies. To demonstrate that your engine meets the intent of this section, the OBD system meeting alternative specifications must address all the provisions described in this paragraph (b) and in paragraph (c) of this section. The following clarifications and exceptions apply for engines certified under this part: (1) We may approve a small manufacturer's request to delay complying with the requirements of this section for up to three model years if that manufacturer has not certified those engines or other comparable engines in California for those model years. (2) For engines not certified in California, references to vehicles meeting certain California Air Resources Board emission standards are understood to refer to the corresponding EPA emission standards for a given family, where applicable. Use good engineering judgment to correlate the specified standards with the EPA standards that apply under this part. You must describe in your application for certification how you will perform testing to demonstrate compliance with OBD requirements to represent all your engine families over five or fewer model years. (3) Engines must comply with OBD requirements throughout the useful life as specified in § 1036.104(e). (4) The purpose and applicability statements in 13 CCR 1971.1(a) and (b) do not apply. (5) Emission thresholds apply as follows: (i) Spark-ignition engines are subject to a NO X (ii) Compression-ignition engines are subject to a NO X (iii) All engines are subject to HC and CO thresholds as specified in 13 CCR 1968.2 and 1971.1, except that the “applicable standards” for determining these thresholds are 0.14 g/hp·hr for HC, 14.4 g/hp·hr for CO from spark-ignition engines, and 15.5 g/hp·hr for CO from compression-ignition engines. (iv) Compression-ignition engines may be exempt from certain monitoring in 13 CCR 1968.2 and 1971.1 based on specified test-out criteria. To calculate these test-out criteria, the “applicable standards” are 0.20 g/hp·hr for NO X (6) The provisions related to verification of in-use compliance in 13 CCR 1971.1(l)(4) do not apply. The provisions related to manufacturer self-testing in 13 CCR 1971.5(c) also do not apply. (7) The deficiency provisions described in paragraph (d) of this section apply instead of 13 CCR 1971.1(k). (8) Include the additional data-stream signals in 13 CCR 1971.1(h)(4.2.3)(E), (F), and (G) as freeze-frame conditions as required in 13 CCR 1971.1(h)(4.3). (9) Design compression-ignition engines to make the following additional data-stream signals available on demand with a generic scan tool according to 13 CCR 1971.1(h)(4.2), if the engine is so equipped with the relevant components and OBD monitoring is required for those components (or modeling is required for some parameter related to those components): (i) Engine and vehicle parameters. (ii) Diesel oxidation catalyst parameters. (iii) Particulate filter parameters. (iv) EGR parameters. (v) SCR parameters. (vi) Derating parameters. (10) Design spark-ignition engines to make the following additional parameters available for reading with a generic scan tool, if applicable: (i) Air-fuel enrichment parameters. (ii) [Reserved] (11) If you have an approved Executive order from the California Air Resources Board for a given engine family, we may rely on that Executive order to evaluate whether you meet federal OBD requirements for that same engine family or an equivalent engine family. Engine families are equivalent if they are identical in all aspects material to emission characteristics; for example, we would consider different inducement strategies and different warranties not to be material to emission characteristics relevant to these OBD testing requirements. EPA would count two equivalent engine families as one for the purposes of determining OBD demonstration testing requirements. Send us the following information: (i) You must submit additional information as needed to demonstrate that you meet the requirements of this section that are not covered by the California Executive order. (ii) Send us results from any testing you performed for certifying engine families (including equivalent engine families) with the California Air Resources Board, including the results of any testing performed under 13 CCR 1971.1(l) for verification of in-use compliance and 13 CCR 1971.5(c) for manufacturer self-testing within the deadlines set out in 13 CCR 1971.1 and 1971.5. (iii) We may require that you send us additional information if we need it to evaluate whether you meet the requirements of this paragraph (b)(11). This may involve sending us copies of documents you send to the California Air Resources Board. (12) You may ask us to approve conditions for which the diagnostic system may disregard trouble codes, as described in 13 CCR 1971.1(g)(5.3)-(5.6). (13) References to the California ARB Executive Officer are deemed to be the EPA Administrator. (14) The definition of “Active Technology” in 13 CCR 1971.1(c) does not apply. (15) The standardization requirements in 13 CCR 1971.1(h)(5.4) do not apply. (16) The data storage requirements in 13 CCR 1971.1(h)(6.1) related to the standardization requirements in 13 CCR 1971.1(h)(5.4) do not apply. (17) The certification documentation requirement related to “Active Technology” in 13 CCR 1971.1(j)(2.32) does not apply. (18) The monitoring system demonstration requirements in 13 CCR 1971.1(i)(4.3.2)(C) related to CO 2 (c) Design the diagnostic system to display the following information in the cab: (1) For inducements specified in § 1036.111 and any other AECD that derates engine output related to SCR or DPF systems, indicate the fault code for the detected problem, a description of the fault code, and the current speed restriction. For inducement faults under § 1036.111, identify whether the fault condition is for DEF level, DEF quality, or tampering; for other faults, identify whether the fault condition is related to SCR or DPF systems. If there are additional derate stages, also indicate the next speed restriction and the time remaining until starting the next restriction. If the derate involves something other than restricting vehicle speed, such as a torque derate, adjust the information to correctly identify any current and pending restrictions. (2) Identify on demand the total number of diesel particulate filter regeneration events that have taken place since installing the current particulate filter. (3) Identify on demand the historical and current rate of DEF consumption, such as gallons of DEF consumed per mile or gallons of DEF consumed per gallon of diesel fuel consumed. Design the system to allow the operator to reset the current rate of DEF consumption. (d) You may ask us to accept as compliant an engine that does not fully meet specific requirements under this section. The following provisions apply regarding OBD system deficiencies: (1) We will not approve a deficiency for gasoline-fueled or diesel-fueled engines if it involves the complete lack of a major diagnostic monitor, such as monitors related to exhaust aftertreatment devices, oxygen sensors, air-fuel ratio sensors, NO X (2) We will approve a deficiency only if you show us that full compliance is infeasible or unreasonable considering any relevant factors, such as the technical feasibility of a given monitor, or the lead time and production cycles of vehicle designs and programmed computing upgrades. (3) Our approval for a given deficiency applies only for a single model year, though you may continue to ask us to extend a deficiency approval in renewable one-year increments. We may approve an extension if you demonstrate an acceptable level of progress toward compliance and you show that the necessary hardware or software modifications would pose an unreasonable burden. We will approve a deficiency for more than three years only if you further demonstrate that you need the additional lead time to make substantial changes to engine hardware. (4) We will not approve deficiencies retroactively. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 28210, Apr. 18, 2024; 89 FR 29739, Apr. 22, 2024; 91 FR 7775, Feb. 18, 2026] § 1036.111 Inducements related to SCR. Engines using SCR to control emissions depend on a constant supply of diesel exhaust fluid (DEF). This section describes how manufacturers must design their engines to derate power output to induce operators to take appropriate actions to ensure the SCR system is working properly. The requirements of this section apply equally for engines installed in heavy-duty vehicles at or below 14,000 lbs GVWR. The requirements of this section apply starting in model year 2027, though you may comply with the requirements of this section in earlier model years. (a) General provisions. (1) As described in § 1036.110, this section relies on terms and requirements specified for OBD systems by California ARB in 13 CCR 1968.2 and 1971.1 (incorporated by reference, see § 1036.810). (2) The provisions of this section apply differently based on an individual vehicle's speed history. A vehicle's speed category is based on the OBD system's recorded value for average speed for the preceding 30 hours of non-idle engine operation. The vehicle speed category applies at the point that the engine first detects an inducement triggering condition identified under paragraph (b) of this section and continues to apply until the inducement triggering condition is fully resolved as specified in paragraph (e) of this section. Non-idle engine operation includes all operating conditions except those that qualify as idle based on OBD system controls as specified in 13 CCR 1971.1(h)(5.4.10). Apply speed derates based on the following categories: Table 1 to Paragraph ( a Vehicle category a Average speed Low-speed speed <15. Medium-speed 15 ≤ speed <25. High-speed speed ≥25. a (3) Where engines derate power output as specified in this section, the derate must decrease vehicle speed by 1 mi/hr for every five minutes of engine operation until reaching the specified derate speed. This paragraph (a)(3) applies at the onset of an inducement, at any transition to a different step of inducement, and for any derate that recurs under paragraph (e)(3) of this section. (b) Inducement triggering conditions. (1) DEF supply falling to 2.5 percent of DEF tank capacity or a level corresponding to three hours of engine operation, based on available information on DEF consumption rates. (2) DEF quality failing to meet your concentration specifications. (3) Any signal indicating that a catalyst is missing. (4) Open circuit faults related to the following: DEF tank level sensor, DEF pump, DEF quality sensor, SCR wiring harness, NO X (c) [Reserved] (d) Derate schedule. (1) Apply speed-limiting derates according to the following schedule: Table 2 to Paragraph ( d a High-speed vehicles Medium-speed vehicles Low-speed vehicles Hours of Maximum speed Hours of Maximum speed Hours of Maximum speed 0 65 0 55 0 45 6 60 6 50 5 40 12 55 12 45 10 35 20 50 45 40 30 25 86 45 70 35 119 40 90 25 144 35 164 25 a (2) You may design and produce engines that will be installed in motorcoaches with an alternative derate schedule that starts with a 65 mi/hr derate when an inducement triggering condition is first detected, steps down to 50 mi/hr after 80 hours, and concludes with a final derate speed of 25 mi/hr after 180 hours of non-idle operation. (e) Deactivating derates. (1) Evaluate whether the detected inducement triggering condition continues to apply. Deactivate derates if the engine confirms that the detected inducement triggering condition is resolved. (2) Allow a generic scan tool to deactivate inducement triggering codes while the vehicle is not in motion. (3) Treat any detected inducement triggering condition that recurs within 40 hours of engine operation as the same detected inducement triggering condition, which would restart the derate at the same point in the derate schedule that the system last deactivated the derate. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29739, Apr. 22, 2024] § 1036.115 Other requirements. Engines that are required to meet the emission standards of this part must meet the following requirements, except as noted elsewhere in this part: (a) Crankcase emissions. (1) Engines equipped with turbochargers, pumps, blowers, or superchargers for air induction may discharge crankcase emissions to the ambient atmosphere if the emissions are added to the exhaust emissions (either physically or mathematically) during all emission testing. (2) If you take advantage of this exception, you must manufacture the engines so that all crankcase emissions can be routed into the applicable sampling systems specified in 40 CFR part 1065. You must also account for deterioration in crankcase emissions when determining exhaust deterioration factors as described in § 1036.240(c)(5). (b) Fuel mapping. (c) Evaporative and refueling emissions. (1) For complete heavy-duty vehicles you produce, you must certify the vehicles to emission standards as specified in 40 CFR 1037.103. (2) For incomplete heavy-duty vehicles, and for engines used in vehicles you do not produce, you do not need to certify your engines to evaporative and refueling emission standards or otherwise meet those standards. However, vehicle manufacturers certifying their vehicles with your engines may depend on you to produce your engines according to their specifications. Also, your engines must meet applicable exhaust emission standards in the installed configuration. (d) Torque broadcasting. (e) EPA access to broadcast information. (f) Adjustable parameters. (1) We may require that you set adjustable parameters to any specification within the practically adjustable range during any testing, including certification testing, selective enforcement auditing, or in-use testing. (2) General provisions apply for adjustable parameters as specified in 40 CFR 1068.50. (3) DEF supply and DEF quality are adjustable parameters. The physically adjustable range includes any amount of DEF for which the engine's diagnostic system does not trigger inducement provisions under § 1036.111. (g) Prohibited controls. General provisions. (2) Vanadium sublimation in SCR catalysts. (i) Identify the threshold temperature for vanadium sublimation for your specified SCR catalyst formulation as described in 40 CFR 1065.1113 through 1065.1121. (ii) Describe how you designed your engine to prevent catalyst inlet temperatures from exceeding the temperature you identify in paragraph (g)(2)(i) of this section, including consideration of engine wear through the useful life. Also describe your design for catalyst protection in case catalyst temperatures exceed the specified temperature. In your description, include how you considered elevated catalyst temperature resulting from sustained high-load engine operation, catalyst exotherms, particulate filter regeneration, and component failure resulting in unburned fuel in the exhaust stream. (h) Defeat devices. (1) The conditions of concern were substantially included in the applicable procedure for duty-cycle testing as described in subpart F of this part. (2) You show your design is necessary to prevent engine (or vehicle) damage or accidents. Preventing engine damage includes preventing damage to aftertreatment or other emission-related components. (3) The reduced effectiveness applies only to starting the engine. (4) The AECD applies only for engines that will be installed in emergency vehicles, (i) DEF tanks. (j) Special provisions for spark-ignition engines. (1) Catalyst bed temperature during extended idle may not fall below 350 °C, or a lower temperature that we approve. Describe how you designed your engine to meet this requirement in your application for certification. You may ask us to approve alternative strategies to prevent emissions from increasing during idle. (2) In addition to the information requirements of § 1036.205(b), describe why you rely on any AECDs instead of other engine designs for thermal protection of catalyst or other emission-related components. Also describe the accuracy of any modeled or measured temperatures used to activate the AECD. We may ask you to submit a second-by-second comparison of any modeled and measured component temperatures as part of your application for certification. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29740, Apr. 22, 2024; 91 FR 7775, Feb. 18, 2026] § 1036.120 Emission-related warranty requirements. (a) General requirements. (1) It is designed, built, and equipped so it conforms at the time of sale to the ultimate purchaser with the requirements of this part. (2) It is free from defects in materials and workmanship that may keep it from meeting these requirements. (b) Warranty period. Table 1 to Paragraph ( b Primary intended service class Model year 2026 and earlier Model year 2027 and later Mileage Years Hours Mileage Years Hours Spark-Ignition HDE 50,000 5 160,000 10 8,000 Light HDE 50,000 5 210,000 10 10,000 Medium HDE 100,000 5 280,000 10 14,000 Heavy HDE 100,000 5 450,000 10 22,000 (c) Components covered. (d) Limited applicability. (e) Owners manual. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29740, Apr. 22, 2024] § 1036.125 Maintenance instructions and allowable maintenance. Maintenance includes any inspection, adjustment, cleaning, repair, or replacement of components and is classified as either emission-related or not emission-related and each of these can be classified as either scheduled or unscheduled. Further, some emission-related maintenance is also classified as critical emission-related maintenance. Give the ultimate purchaser of each new engine written instructions for maintaining and using the engine. As described in paragraph (h) of this section, these instructions must identify how owners properly maintain and use engines to clarify responsibilities for regulatory requirements such as emission-related warranty and defect reporting. (a) Critical emission-related maintenance. (1) Maintenance demonstration. (i) You present data showing that, if a lack of maintenance increases emissions, it also unacceptably degrades the engine's performance. (ii) You design and produce your engines with a system we approve that displays a visible signal to alert drivers that maintenance is due, either as a result of component failure or the appropriate degree of engine or vehicle operation. The signal must clearly display “maintenance needed”, “check engine”, or a similar message that we approve. The signal must be continuous while the engine is operating and not be easily eliminated without performing the specified maintenance. Your maintenance instructions must specify resetting the signal after completing the specified maintenance. We must approve the method for resetting the signal. You may not design the system to be less effective at the end of the useful life. If others install your engine in their vehicle, you may rely on installation instructions to ensure proper mounting and operation of the display. Disabling or improperly resetting the system for displaying these maintenance-related signals without performing the indicated maintenance violates the tampering prohibition in 42 U.S.C. 7522(a)(3). (iii) You present survey data showing that at least 80 percent of engines in the field get the maintenance you specify at the recommended intervals. (iv) You provide the maintenance free of charge and clearly say so in your maintenance instructions. (v) You otherwise show us that the maintenance is reasonably likely to be done at the recommended intervals. (2) Minimum scheduled maintenance intervals. Table 1 to Paragraph ( a Components Spark-ignition HDE Light HDE Medium HDE Heavy HDE Spark plugs 25,000 (750) DEF filters 100,000 (3,000) 100,000 (3,000) 100,000 (3,000) Crankcase ventilation valves and filters 60,000 (1,800) 60,000 (1,800) 60,000 (1,800) 60,000 (1,800) Ignition wires and coils 50,000 (1,500) Oxygen sensors 80,000 (2,400) Air injection system components 110,000 (3,300) Sensors, actuators, and related control modules that are not integrated into other systems 100,000 (3,000) 100,000 (3,000) 150,000 (4,500) 150,000 (4,500) Particulate filtration systems (other than filter substrates) 100,000 (3,000) 100,000 3,000) 250,000 7,500) 250,000 (7,500) Catalyst systems (other than catalyst substrates), fuel injectors, electronic control modules, hybrid system components, turbochargers, and EGR system components (including filters and coolers) 110,000 (3,300) 110,000 (3,300) 185,000 5,550) 435,000 (13,050) Catalyst substrates and particulate filter substrates 200,000 (10,000) 270,000 (13,000) 350,000 (17,000) 650,000 (32,000) Table 2 to Paragraph ( a Component Accumulated miles (hours) for components Spark-ignition HDE Light HDE Medium HDE Heavy HDE Spark plugs 25,000 (750) EGR-related filters and coolers, fuel injectors, and crankcase ventilation valves and filters 50,000 (1,500) 50,000 (1,500) 50,000 (1,500) 50,000 (1,500) DEF filters 50,000 (1,500) 50,000 (1,500) 50,000 (1,500) Ignition wires and coils 50,000 (1,500) Oxygen sensors 80,000 (2,400) Air injection system components 100,000 (3,000) Catalyst system components, EGR system components (other than filters or coolers), particulate filtration system components, and turbochargers 100,000 (3,000) 100,000 (3,000) 100,000 (3,000), then 50,000 (4,500) 100,000 (3,000), then 150,000 (4,500) (3) New technology. (i) Your request must include your recommended maintenance interval, including data to support the need for the maintenance, and a demonstration that the maintenance is likely to occur at the recommended interval using one of the conditions specified in paragraph (a)(1) of this section. (ii) For any such new technology, we will publish a Federal Register (4) System components. (i) Catalyst system refers to the aftertreatment assembly used for gaseous emission control and generally includes catalyst substrates, substrate housings, exhaust gas temperature sensors, gas concentration sensors, and related control modules. SCR-based catalyst systems also include DEF level sensors, DEF quality sensors, and DEF temperature sensors. (ii) Particulate filtration system refers to the aftertreatment assembly used for exhaust PM filtration and generally includes filter substrates, substrate housings, pressure sensors, pressure lines and tubes, exhaust gas temperature sensors, fuel injectors for active regeneration, and related control modules. (b) Recommended additional maintenance. (c) Special maintenance. (d) Noncritical emission-related maintenance. (e) Maintenance that is not emission-related. (f) [Reserved] (g) Payment for scheduled maintenance. (1) Each affected component was not in general use on similar engines before 1980. (2) The primary function of each affected component is to reduce emissions. (3) The cost of the maintenance is more than 2 percent of the price of the engine. (4) Failure to perform the maintenance would not cause clear problems that would significantly degrade the engine's performance. (h) Owners manual. (1) Clearly describe the scheduled maintenance steps, consistent with the provisions of this section, using nontechnical language as much as possible. Include a list of components for which you will cover scheduled replacement costs. (2) Identify all maintenance you consider necessary for the engine to be considered properly maintained for purposes of making valid warranty claims. Describe what documentation you consider appropriate for making these demonstrations. Note that you may identify failure to repair critical emission-related components as improper maintenance if the repairs are related to an observed defect. Your maintenance instructions under this section may not require components or service identified by brand, trade, or corporate name. Also, do not directly or indirectly require that the engine be serviced by your franchised dealers or any other service establishments with which you have a commercial relationship. However, you may disregard these limitations on your maintenance requirements if you do one of the following things: (i) Provide a component or service without charge under the purchase agreement. (ii) Get us to waive this prohibition in the public's interest by convincing us the engine will work properly only with the identified component or service. (3) Describe how the owner can access the OBD system to troubleshoot problems and find emission-related diagnostic information and codes stored in onboard monitoring systems as described in § 1036.110(b) and (c). These instructions must at a minimum include identification of the OBD communication protocol used, location and type of OBD connector, brief description of what OBD is (including type of information stored, what a MIL is, and explanation that some MILs may self-extinguish), and a note that generic scan tools can provide engine maintenance information. (4) Describe the elements of the emission control system and provide an overview of how they function. (5) Include one or more diagrams of the engine and its emission-related components with the following information: (i) The flow path for intake air and exhaust gas. (ii) The flow path of evaporative and refueling emissions for spark-ignition engines, and DEF for compression-ignition engines, as applicable. (iii) The flow path of engine coolant if it is part of the emission control system described in the application for certification. (iv) The identity, location, and arrangement of relevant sensors, DEF heater and other DEF delivery components, and other critical emission-related components. Terminology to identify components must be consistent with codes you use for the OBD system. (6) Include one or more exploded-view drawings that allow the owner to identify the following components: EGR valve, EGR actuator, EGR cooler, all emission sensors (such as NO X e.g., (7) Include the following statement: “Technical service bulletins, emission-related recalls, and other information for your engine may be available at www.nhtsa.gov/recalls (8) Include a troubleshooting guide to address the following warning signals related to SCR inducement: (i) The inducement derate schedule (including indication that inducements will begin prior to the DEF tank being completely empty). (ii) The meaning of any trouble lights that indicate specific problems ( e.g., (iii) A description of the three types of SCR-related derates (DEF level, DEF quality and tampering) and that further information on the inducement cause ( e.g., (9) Describe how to access OBD fault codes related to DPF-related derates. (10) Identify a website for the service information required in 40 CFR 86.010-38(j). [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29740, Apr. 22, 2024] § 1036.130 Installation instructions for vehicle manufacturers. (a) If you sell an engine for someone else to install in a vehicle, give the engine installer instructions for installing it consistent with the requirements of this part. Include all information necessary to ensure that an engine will be installed in its certified configuration. (b) Make sure these instructions have the following information: (1) Include the heading: “Emission-related installation instructions”. (2) State: “Failing to follow these instructions when installing a certified engine in a heavy-duty motor vehicle violates federal law, subject to fines or other penalties as described in the Clean Air Act.” (3) Provide all instructions needed to properly install the exhaust system and any other components. Include any appropriate instructions for configuring the exhaust system in the vehicle to allow for collecting emission samples for in-use testing where that is practical. (4) Describe any necessary steps for installing any diagnostic system required under § 1036.110. (5) Describe how your certification is limited for any type of application. For example, if you certify engines only for use in emergency vehicles, you must make clear that the engine may only be installed in emergency vehicles. (6) Describe any other instructions to make sure the installed engine will operate according to design specifications in your application for certification. This may include, for example, instructions for installing aftertreatment devices when installing the engines. (7) Give the following instructions if you do not ship diesel exhaust fluid tanks with your engines: (i) Specify that vehicle manufacturers must install diesel exhaust fluid tanks meeting the specifications of § 1036.115(i). (ii) Describe how vehicle manufacturers must install diesel exhaust fluid tanks with sensors as needed to meet the requirements of §§ 1036.110 and 1036.111. (8) State: “If you install the engine in a way that makes the engine's emission control information label hard to read during normal engine maintenance, you must place a duplicate label on the vehicle, as described in 40 CFR 1068.105.” (9) Describe how vehicle manufacturers need to apply stickers to qualifying vehicles as described in § 1036.136 if you certify engines to the Clean Idle NO X (c) Give the vehicle manufacturer fuel map results as described in § 1036.505(b). (d) You do not need installation instructions for engines that you install in your own vehicles. (e) Provide instructions in writing or in an equivalent format. For example, you may post instructions on a publicly available website for downloading or printing. If you do not provide the instructions in writing, explain in your application for certification how you will ensure that each installer is informed of the installation requirements. [88 FR 4487, Jan. 24, 2023, as amended at 91 FR 7775, Feb. 18, 2026] § 1036.135 Labeling. (a) Assign each engine a unique identification number and permanently affix, engrave, or stamp it on the engine in a legible way. (b) At the time of manufacture, affix a permanent and legible label identifying each engine. The label must meet the requirements of 40 CFR 1068.45. (c) The label must— (1) Include the heading “EMISSION CONTROL INFORMATION”. (2) Include your full corporate name and trademark. You may identify another company and use its trademark instead of yours if you comply with the branding provisions of 40 CFR 1068.45. (3) Include EPA's standardized designation for the engine family. (4) Identify the primary intended service class. (5) State the engine's displacement (in liters); however, you may omit this from the label if all the engines in the engine family have the same per-cylinder displacement and total displacement. (6) State the date of manufacture [DAY (optional), MONTH, and YEAR]; however, you may omit this from the label if you stamp, engrave, or otherwise permanently identify it elsewhere on the engine, in which case you must also describe in your application for certification where you will identify the date on the engine. (7) State the NO X X (8) State: “THIS ENGINE COMPLIES WITH U.S. EPA REGULATIONS FOR [MODEL YEAR] HEAVY-DUTY HIGHWAY ENGINES.” (9) Identify any limitations on your certification. For example, if you certify engines with one or more approved AECDs for emergency vehicle applications under § 1036.115(h)(4), include the statement: “THIS ENGINE IS FOR INSTALLATION IN EMERGENCY VEHICLES ONLY”. (d) You may add information to the emission control information label as follows: (1) You may identify other emission standards that the engine meets or does not meet. You may add the information about the other emission standards to the statement we specify, or you may include it in a separate statement. (2) You may add other information to ensure that the engine will be properly maintained and used. (3) You may add appropriate features to prevent counterfeit labels. For example, you may include the engine's unique identification number on the label. (e) You may ask us to approve modified labeling requirements in this part if you show that it is necessary or appropriate. We will approve your request if your alternate label is consistent with the requirements of this part. We may also specify modified labeling requirements to be consistent with the intent of 40 CFR part 1037. (f) If you obscure the engine label while installing the engine in the vehicle such that the label cannot be read during normal maintenance, you must place a duplicate label on the vehicle. If others install your engine in their vehicles in a way that obscures the engine label, we require them to add a duplicate label on the vehicle (see 40 CFR 1068.105); in that case, give them the number of duplicate labels they request and keep the following records for at least five years: (1) Written documentation of the request from the vehicle manufacturer. (2) The number of duplicate labels you send for each engine family and the date you sent them. [88 FR 4487, Jan. 24, 2023, as amended at 91 FR 7775, Feb. 18, 2026] § 1036.136 Clean Idle sticker. (a) Design and produce stickers showing that your engines meet the federal Clean Idle standard if you certify engines to the Clean Idle NO X (1) Meet the requirements of 40 CFR 1068.45 for permanent labels. The preferred location for sticker placement is on the driver's side of the hood. (2) Include one or both of your corporate name and trademark. (3) Identify that the engine is qualified to meet the federal Clean Idle NO X (4) Include a serial number or other method to confirm that stickers have been properly applied to vehicles. (b) The following provisions apply for placing Clean Idle stickers on vehicles with installed engines that have been certified to the NO X (1) If you install engines in vehicles you produce, you must apply a sticker to each vehicle certified to the Clean Idle standard. (2) If you ship engines for others to install in vehicles, include in your purchasing documentation the manufacturer's request for a specific number of labels corresponding to the number of engines ordered. Supply the vehicle manufacturer with exactly one sticker for each shipped engine certified to the Clean Idle standard. Prepare your emission-related installation instructions to ensure that vehicle manufacturers meet all application requirements. Keep the following records for at least five years: (i) Written documentation of the vehicle manufacturer's request for stickers. (ii) Tracking information for stickers you send and the date you sent them. (c) The provisions in 40 CFR 1068.101 apply for the Clean Idle sticker in the same way that those provisions apply for emission control information labels. § 1036.140 Primary intended service class and engine cycle. You must identify a single primary intended service class for each engine family that best describes vehicles for which you design and market the engine, as follows: (a) Divide compression-ignition engines into primary intended service classes based on the following engine and vehicle characteristics: (1) Light HDE includes engines that are not designed for rebuild and do not have cylinder liners. Vehicle body types in this group might include any heavy-duty vehicle built from a light-duty truck chassis, van trucks, multi-stop vans, and some straight trucks with a single rear axle. Typical applications would include personal transportation, light-load commercial delivery, passenger service, agriculture, and construction. The GVWR of these vehicles is normally at or below 19,500 pounds. (2) Medium HDE includes engines that may be designed for rebuild and may have cylinder liners. Vehicle body types in this group would typically include school buses, straight trucks with single rear axles, city tractors, and a variety of special purpose vehicles such as small dump trucks, and refuse trucks. Typical applications would include commercial short haul and intra-city delivery and pickup. Engines in this group are normally used in vehicles whose GVWR ranges from 19,501 to 33,000 pounds. (3) Heavy HDE includes engines that are designed for multiple rebuilds and have cylinder liners. Vehicles in this group are normally tractors, trucks, straight trucks with dual rear axles, and buses used in inter-city, long-haul applications. These vehicles normally exceed 33,000 pounds GVWR. (b) Divide spark-ignition engines into primary intended service classes as follows: (1) Spark-ignition engines that are best characterized by paragraph (a)(1) or (2) of this section are in a separate Spark-ignition HDE primary intended service class. (2) Spark-ignition engines that are best characterized by paragraph (a)(3) of this section are included in the Heavy HDE primary intended service class along with compression-ignition engines. Gasoline-fueled engines are presumed not to be characterized by paragraph (a)(3) of this section; for example, vehicle manufacturers may install some number of gasoline-fueled engines in Class 8 trucks without causing the engine manufacturer to consider those to be Heavy HDE. (c) References to “spark-ignition standards” in this part relate only to the spark-ignition engines identified in paragraph (b)(1) of this section. References to “compression-ignition standards” in this part relate to compression-ignition engines, to spark-ignition engines optionally certified to standards that apply to compression-ignition engines, and to all engines identified under paragraph (b)(2) of this section as Heavy HDE. § 1036.150 Interim provisions. The provisions in this section apply instead of other provisions in this part. This section describes when these interim provisions expire, if applicable. (a) Transitional ABT credits for NO X emissions. X (1) Discounted credits. X (2) Partial credits. (i) Calculate credits as described in § 1036.705 relative to a NO X X (ii) Engines must meet a NO X X X Std FTPNOx Std [cycle]NOx X (iii) For engines selected for in-use testing, we may specify that you perform testing as described in 40 CFR part 86, subpart T, or as described in subpart E of this part. (iv) Add the statement “Partial credit” to the emission control information label. (3) Full credits. X (4) 2026 service class pull-ahead credits. X X X (b) [Reserved] (c) Engine cycle classification. (d) Small manufacturers. (e) [Reserved] (f) Testing exemption for hydrogen engines. (g)-(j) [Reserved] (k) Limited production volume allowance under ABT. (1) Engines must meet all the standards and other requirements that apply under 40 CFR part 86 for model year 2026. Engine must be certified in separate engine families that qualify for carryover certification as described in § 1036.235(d). (2) The NO X X (3) Label the engine as described in 40 CFR 86.095-35, but include the following alternate compliance statement: “THIS ENGINE CONFORMS TO U.S. EPA REGULATIONS FOR MODEL YEAR 2026 ENGINES UNDER 40 CFR 1036.150(k).” (l) [Reserved] (m) Infrequent regeneration. 2 (n) Supplying fuel maps. (o) Engines used in glider vehicles. (p) [Reserved] (q) Confirmatory and in-use testing of fuel maps defined in § 1036.505(b). (r) Fuel maps for the transition to updated GEM. (2) Compliance testing will be based on the GEM version you used to generate fuel maps for certification. For example, if you perform a selective enforcement audit with respect to fuel maps, use the same GEM version that you used to generate fuel maps for certification. Similarly, we will use the same GEM version that you used to generate fuel maps for certification if we perform confirmatory testing with one of your engine families. (s) Fuel consumption compliance testing. (1) For model years 2016 through 2020, measure emissions using the FTP duty cycle specified in § 1036.512 and the SET duty cycle specified in 40 CFR 86.1362, as applicable. (2) The following provisions apply for model years 2021 through 2026: (i) [Reserved] (ii) You may demonstrate compliance with SET-based fuel consumption standards using the SET duty cycle specified in 40 CFR 86.1362 if you collect emissions with continuous sampling. Integrate the test results by mode to establish separate emission rates for each mode (including the transition following each mode, as applicable). Apply the CO 2 (t) Model year 2027 compliance date. (1) Split model year. (2) Optional early compliance. (3) Certification. (i) You may generate emission credits only with engines that are certified under this part 1036. (ii) In your production report under § 1036.250(a), identify production volumes separately for the two parts of the model year. (iii) OBD testing demonstrations apply singularly for the full model year. (u) Crankcase emissions. (v) OBD communication protocol. (w) [Reserved] (x) Powertrain testing for criteria pollutants. (y) NO X compliance allowance for in-use testing. X X X X (z) Alternate family pass criteria for in-use testing. (1) Start by measuring emissions from five engines using the procedures described in subpart E of this part and § 1036.530. If four or five engines comply fully with the off-cycle bin standards, the engine family passes and you may stop testing. (2) If exactly two of the engines tested under paragraph (z)(1) of this section do not comply fully with the off-cycle bin standards, test five more engines. If these additional engines all comply fully with the off-cycle bin standards, the engine family passes and you may stop testing. (3) If three or more engines tested under paragraphs (z)(1) and (2) of this section do not comply fully with the off-cycle bin standards, test a total of at least 10 but not more than 15 engines. Calculate the arithmetic mean of the bin emissions from all the engine tests as specified in § 1036.530(g) for each pollutant. If the mean values are at or below the off-cycle bin standards, the engine family passes. If the mean value for any pollutant is above an off-cycle bin standard, the engine family fails. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29740, Apr. 22, 2024; 91 FR 7775, Feb. 18, 2026] Subpart C—Certifying Engine Families § 1036.201 General requirements for obtaining a certificate of conformity. (a) You must send us a separate application for a certificate of conformity for each engine family. A certificate of conformity is valid from the indicated effective date until December 31 of the model year for which it is issued. (b) The application must contain all the information required by this part and must not include false or incomplete statements or information (see § 1036.255). (c) We may ask you to include less information than we specify in this subpart, as long as you maintain all the information required by § 1036.250. (d) You must use good engineering judgment for all decisions related to your application (see 40 CFR 1068.5). (e) An authorized representative of your company must approve and sign the application. (f) See § 1036.255 for provisions describing how we will process your application. (g) We may require you to deliver your test engines to a facility we designate for our testing (see § 1036.235(c)). Alternatively, you may choose to deliver another engine that is identical in all material respects to the test engine, or another engine that we determine can appropriately serve as an emission-data engine for the engine family. (h) For engines that become new after being placed into service, such as rebuilt engines installed in new vehicles, we may specify alternate certification provisions consistent with the intent of this part. See 40 CFR 1068.120(h) and the definition of “new motor vehicle engine” in § 1036.801. § 1036.205 Requirements for an application for certification. This section specifies the information that must be in your application, unless we ask you to include less information under § 1036.201(c). We may require you to provide additional information to evaluate your application. (a) Identify the engine family's primary intended service class and describe how that conforms to the specifications in § 1036.140. Also, describe the engine family's specifications and other basic parameters of the engine's design and emission controls with respect to compliance with the requirements of this part. List the fuel type on which your engines are designed to operate (for example, gasoline, diesel fuel, or natural gas). For engines that can operate on multiple fuels, identify whether they are dual-fuel or flexible-fuel engines; also identify the range of mixtures for operation on blended fuels, if applicable. List each engine configuration in the engine family. List the rated power for each engine configuration. (b) Explain how the emission control system operates. Describe in detail all system components for controlling greenhouse gas and criteria pollutant emissions, including all auxiliary emission control devices (AECDs) and all fuel-system components you will install on any production or test engine. Identify the part number of each component you describe. For this paragraph (b), treat as separate AECDs any devices that modulate or activate differently from each other. Include all the following: (1) Give a general overview of the engine, the emission control strategies, and all AECDs. (2) Describe each AECD's general purpose and function. (3) Identify the parameters that each AECD senses (including measuring, estimating, calculating, or empirically deriving the values). Include engine-based parameters and state whether you simulate them during testing with the applicable procedures. (4) Describe the purpose for sensing each parameter. (5) Identify the location of each sensor the AECD uses. (6) Identify the threshold values for the sensed parameters that activate the AECD. (7) Describe the parameters that the AECD modulates (controls) in response to any sensed parameters, including the range of modulation for each parameter, the relationship between the sensed parameters and the controlled parameters and how the modulation achieves the AECD's stated purpose. Use graphs and tables, as necessary. (8) Describe each AECD's specific calibration details. This may be in the form of data tables, graphical representations, or some other description. (9) Describe the hierarchy among the AECDs when multiple AECDs sense or modulate the same parameter. Describe whether the strategies interact in a comparative or additive manner and identify which AECD takes precedence in responding, if applicable. (10) Explain the extent to which the AECD is included in the applicable test procedures specified in subpart F of this part. (11) Do the following additional things for AECDs designed to protect engines or vehicles: (i) Identify any engine and vehicle design limits that make protection necessary and describe any damage that would occur without the AECD. (ii) Describe how each sensed parameter relates to the protected components' design limits or those operating conditions that cause the need for protection. (iii) Describe the relationship between the design limits/parameters being protected and the parameters sensed or calculated as surrogates for those design limits/parameters, if applicable. (iv) Describe how the modulation by the AECD prevents engines and vehicles from exceeding design limits. (v) Explain why it is necessary to estimate any parameters instead of measuring them directly and describe how the AECD calculates the estimated value, if applicable. (vi) Describe how you calibrate the AECD modulation to activate only during conditions related to the stated need to protect components and only as needed to sufficiently protect those components in a way that minimizes the emission impact. (c) Explain in detail how the engine diagnostic system works, describing especially the engine conditions (with the corresponding diagnostic trouble codes) that cause the malfunction indicator to go on. You may ask us to approve conditions under which the diagnostic system disregards trouble codes as described in § 1036.110. (d) Describe the engines you selected for testing and the reasons for selecting them. (e) Describe any test equipment and procedures that you used, including any special or alternate test procedures you used (see § 1036.501). (f) Describe how you operated the emission-data engine before testing, including the duty cycle and the number of engine operating hours used to stabilize emission levels. Explain why you selected the method of service accumulation. Describe any scheduled maintenance you did. (g) List the specifications of the test fuel to show that it falls within the required ranges we specify in 40 CFR part 1065. (h) Identify the engine family's useful life. (i) Include the warranty statement and maintenance instructions you will give to the ultimate purchaser of each new engine (see §§ 1036.120 and 1036.125). (j) Include the emission-related installation instructions you will provide if someone else installs your engines in their vehicles (see § 1036.130). (k) Describe your emission control information label (see § 1036.135). We may require you to include a copy of the label. (l) Identify the duty-cycle emission standards from § 1036.104(a) and (b) that apply for the engine family. Also identify FELs and FCLs as follows: (1) Identify the NO X (2) Identify the CO 2 (m) Identify the engine family's deterioration factors and describe how you developed them (see § 1036.240). Present any test data you used for this. For engines designed to discharge crankcase emissions to the ambient atmosphere, use the deterioration factors for crankcase emission to determine deteriorated crankcase emission levels of NO X (n) State that you operated your emission-data engines as described in the application (including the test procedures, test parameters, and test fuels) to show you meet the requirements of this part. (o) Present emission data from all valid tests on an emission-data engine to show that you meet emission standards. Note that § 1036.235 allows you to submit an application in certain cases without new emission data. Present emission data as follows: (1) For hydrocarbons (such as NMHC or NMHCE), NO X (2) Identify the value of e CO2FTPFCL (3) If we specify more than one grade of any fuel type (for example, a summer grade and winter grade of gasoline), you need to submit test data only for one grade, unless the regulations of this part specify otherwise for your engine. (p) State that all the engines in the engine family comply with the off-cycle emission standards we specify in § 1036.104 for all normal operation and use when tested as specified in § 1036.530. Describe any relevant testing, engineering analysis, or other information in sufficient detail to support your statement. We may direct you to include emission measurements representing typical engine in-use operation at a range of ambient conditions. For example, we may specify certain transient and steady-state engine operation that is typical for the types of vehicles that use your engines. See § 1036.210. (q) We may ask you to send information to confirm that the emission data you submitted were from valid tests meeting the requirements of this part and 40 CFR part 1065. You must indicate whether there are test results from invalid tests or from any other tests of the emission-data engine, whether or not they were conducted according to the test procedures of subpart F of this part. We may require you to report these additional test results. (r) Describe all adjustable operating parameters (see § 1036.115(f)), including production tolerances. For any operating parameters that do not qualify as adjustable parameters, include a description supporting your conclusion (see 40 CFR 1068.50(c)). Include the following in your description of each adjustable parameter: (1) For practically adjustable operating parameters, include the nominal or recommended setting, the intended practically adjustable range, and the limits or stops used to establish adjustable ranges. State that the limits, stops, or other means of inhibiting adjustment are effective in preventing adjustment of parameters on in-use engines to settings outside your intended practically adjustable ranges and provide information to support this statement. (2) For programmable operating parameters, state that you have restricted access to electronic controls to prevent parameter adjustment on in-use engines that would allow operation outside the practically adjustable range. Describe how your engines are designed to prevent unauthorized adjustments. (s) Provide the information to read, record, and interpret all the information broadcast by an engine's onboard computers and ECMs as described in § 1036.115(d). State that, upon request, you will give us any hardware, software, or tools we would need to do this. (t) State whether your certification is limited for certain engines. For example, you might certify engines only for use in emergency vehicles or in vehicles with hybrid powertrains. If this is the case, describe how you will prevent use of these engines in vehicles for which they are not certified. (u) Unconditionally certify that all the engines in the engine family comply with the requirements of this part, other referenced parts of the CFR, and the Clean Air Act. Note that § 1036.235 specifies which engines to test to show that engines in the entire family comply with the requirements of this part. (v) Include good-faith estimates of U.S.-directed production volumes. Include a justification for the estimated production volumes if they are substantially different than actual production volumes in earlier years for similar models. (w) Include the information required by other subparts of this part. For example, include the information required by § 1036.725 if you participate in the ABT program. (x) Include other applicable information, such as information specified in this part or 40 CFR part 1068 related to requests for exemptions. (y) Name an agent for service located in the United States. Service on this agent constitutes service on you or any of your officers or employees for any action by EPA or otherwise by the United States related to the requirements of this part. (z) For imported engines, identify the following: (1) Describe your normal practice for importing engines. For example, this may include identifying the names and addresses of anyone you have authorized to import your engines. Engines imported by nonauthorized agents are not covered by your certificate. (2) The location of a test facility in the United States where you can test your engines if we select them for testing under a selective enforcement audit, as specified in 40 CFR part 1068, subpart E. (aa) Include information needed to certify vehicles to greenhouse gas standards under 40 CFR part 1037 as described in § 1036.505. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29741, Apr. 22, 2024; 91 FR 7777, Feb. 18, 2026] § 1036.210 Preliminary approval before certification. If you send us information before you finish the application, we may review it and make any appropriate determinations, especially for questions related to engine family definitions, auxiliary emission control devices, adjustable parameters, deterioration factors, testing for service accumulation, and maintenance. Decisions made under this section are considered to be preliminary approval, subject to final review and approval. We will generally not reverse a decision where we have given you preliminary approval, unless we find new information supporting a different decision. If you request preliminary approval related to the upcoming model year or the model year after that, we will make best-efforts to make the appropriate determinations as soon as practicable. We will generally not provide preliminary approval related to a future model year more than two years ahead of time. § 1036.225 Amending applications for certification. Before we issue you a certificate of conformity, you may amend your application to include new or modified engine configurations, subject to the provisions of this section. After we have issued your certificate of conformity, you may send us an amended application any time before the end of the model year requesting that we include new or modified engine configurations within the scope of the certificate, subject to the provisions of this section. You must also amend your application if any changes occur with respect to any information that is included or should be included in your application. (a) You must amend your application before you take any of the following actions: (1) Add an engine configuration to an engine family. In this case, the engine configuration added must be consistent with other engine configurations in the engine family with respect to the design aspects listed in § 1036.230. (2) Change an engine configuration already included in an engine family in a way that may affect emissions, or change any of the components you described in your application for certification. This includes production and design changes that may affect emissions any time during the engine's lifetime. (3) Modify an FEL or FCL for an engine family as described in paragraph (f) of this section. (b) To amend your application for certification, send the relevant information to the Designated Compliance Officer. (1) Describe in detail the addition or change in the engine model or configuration you intend to make. (2) Include engineering evaluations or data showing that the amended engine family complies with all applicable requirements. You may do this by showing that the original emission-data engine is still appropriate for showing that the amended family complies with all applicable requirements. (3) If the original emission-data engine for the engine family is not appropriate to show compliance for the new or modified engine configuration, include new test data showing that the new or modified engine configuration meets the requirements of this part. (4) Include any other information needed to make your application correct and complete. (c) We may ask for more test data or engineering evaluations. You must give us these within 30 days after we request them. (d) For engine families already covered by a certificate of conformity, we will determine whether the existing certificate of conformity covers your newly added or modified engine. You may ask for a hearing if we deny your request (see § 1036.820). (e) The amended application applies starting with the date you submit the amended application, as follows: (1) For engine families already covered by a certificate of conformity, you may start producing a new or modified engine configuration any time after you send us your amended application and before we make a decision under paragraph (d) of this section. However, if we determine that the affected engines do not meet applicable requirements in this part, we will notify you to cease production of the engines and may require you to recall the engines at no expense to the owner. Choosing to produce engines under this paragraph (e) is deemed to be consent to recall all engines that we determine do not meet applicable emission standards or other requirements in this part and to remedy the nonconformity at no expense to the owner. If you do not provide information required under paragraph (c) of this section within 30 days after we request it, you must stop producing the new or modified engines. (2) [Reserved] (f) You may ask us to approve a change to your FEL in certain cases after the start of production, but before the end of the model year. If you change an FEL for CO 2 2 (1) You may ask to raise your FEL for your engine family at any time. In your request, you must show that you will still be able to meet the emission standards as specified in subparts B and H of this part. Use the appropriate FELs/FCLs with corresponding production volumes to calculate emission credits for the model year, as described in subpart H of this part. (2) You may ask to lower the FEL for your engine family only if you have test data from production engines showing that emissions are below the proposed lower FEL (or below the proposed FCL for CO 2 (g) You may produce engines or modify in-use engines as described in your amended application for certification and consider those engines to be in a certified configuration. Modifying a new or in-use engine to be in a certified configuration does not violate the tampering prohibition of 40 CFR 1068.101(b)(1), as long as this does not involve changing to a certified configuration with a higher family emission limit. § 1036.230 Selecting engine families. (a) For purposes of certification to the standards of this part, divide your product line into families of engines that are expected to have similar characteristics for criteria emissions throughout the useful life as described in this section. Your engine family is limited to a single model year. (b) Group engines in the same engine family if they are the same in all the following design aspects: (1) The combustion cycle and fuel. See paragraph (g) of this section for special provisions that apply for dual-fuel and flexible-fuel engines. (2) The cooling system (water-cooled vs. air-cooled). (3) Method of air aspiration, including the location of intake and exhaust valves or ports and the method of intake-air cooling, if applicable. (4) The arrangement and composition of catalytic converters and other aftertreatment devices. (5) Cylinder arrangement (such as in-line vs. vee configurations) and bore center-to-center dimensions. (6) Method of control for engine operation other than governing ( i.e., (7) The numerical level of the applicable criteria emission standards. For example, an engine family may not include engines certified to different family emission limits for criteria emission standards, though you may change family emission limits without recertifying as specified in § 1036.225(f). (c) You may subdivide a group of engines that is identical under paragraph (b) of this section into different engine families if you show the expected criteria emission characteristics are different during the useful life. (d) In unusual circumstances, you may group engines that are not identical with respect to the design aspects listed in paragraph (b) of this section in the same engine family if you show that their criteria emission characteristics during the useful life will be similar. (e) Engine configurations certified as hybrid powertrains may not be included in an engine family with engines that have nonhybrid powertrains. Note that this does not prevent you from including engines in a nonhybrid family if they are used in hybrid vehicles, as long as you certify them based on engine testing. (f) The following additional provisions apply with respect to demonstrating compliance with the fuel consumption standards of 49 CFR 535.5: (1) Use the same engine families you use for criteria pollutants. You may subdivide an engine family into subfamilies that have a different FCL for CO 2 (2) If you certify engines in the family for use as both vocational and tractor engines, you must split your family into two separate subfamilies. (i) Calculate emission credits relative to the vocational engine standard for the number of engines sold into vocational applications and relative to the tractor engine standard for the number of engines sold into non-vocational tractor applications. You may assign the numbers and configurations of engines within the respective subfamilies at any time before submitting the report required by § 1036.730. If the family participates in averaging, banking, or trading, you must identify the type of vehicle in which each engine is installed; we may alternatively allow you to use statistical methods to determine this for a fraction of your engines. Keep records to document this determination. (ii) If you restrict use of the test configuration for your split family only to tractors, or only to vocational vehicles, you must identify a second testable configuration for the other type of vehicle (or an unrestricted configuration). Identify this configuration in your application for certification. The FCL for the engine family applies for this configuration as well as the primary test configuration. (3) If you certify both engine fuel maps and powertrain fuel maps for an engine family, you may split the engine family into two separate subfamilies. Indicate this in your application for certification, and identify whether one or both of these sets of fuel maps applies for each group of engines. If you do not split your family, all engines within the family must conform to the engine fuel maps, including any engines for with the powertrain maps also apply. (4) If you certify in separate engine families engines that could have been certified in vocational and tractor engine subfamilies in the same engine family, count the two families as one family for purposes of determining your obligations with respect to the OBD requirements and in-use testing requirements. Indicate in the applications for certification that the two engine families are covered by this paragraph (f)(4). (5) Except as described in this paragraph (f), engine configurations within an engine family must use equivalent controls. Unless we approve it, you may not produce nontested configurations without the same control hardware included on the tested configuration. (g) You may certify dual-fuel or flexible-fuel engines in a single engine family. You may include dedicated-fuel versions of this same engine model in the same engine family, as long as they are identical to the engine configuration with respect to that fuel type for the dual-fuel or flexible-fuel version of the engine. For example, if you produce an engine that can alternately run on gasoline and natural gas, you can include the gasoline-only and natural gas-only versions of the engine in the same engine family as the dual-fuel engine if engine operation on each fuel type is identical with or without installation of components for operating on the other fuel. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29741, Apr. 22, 2024; 91 FR 7778, Feb. 18, 2026] § 1036.231 Powertrain families. (a) If you choose to perform powertrain testing as specified in § 1036.545, use good engineering judgment to divide your product line into powertrain families that are expected to have similar criteria emissions throughout the useful life as described in this section. Your powertrain family is limited to a single model year. (b) Except as specified in paragraph (c) of this section, group powertrains in the same powertrain family if they share all the following attributes: (1) Have the same engine design aspects as specified in § 1036.230. (2) [Reserved] (3) Number of clutches. (4) Type of clutch ( e.g., (5) Presence and location of a fluid coupling such as a torque converter. (6) Gear configuration, as follows: (i) Planetary ( e.g., (ii) Countershaft ( e.g., (iii) Continuously variable ( e.g., (7) Number of available forward gears, and transmission gear ratio for each available forward gear, if applicable. Count forward gears as being available only if the vehicle has the hardware and software to allow operation in those gears. (8) Transmission oil sump configuration ( e.g., (9) The power transfer configuration of any hybrid technology ( e.g., (10) The type of any RESS ( e.g., (c) For powertrains that share all the attributes described in paragraph (b) of this section, divide them further into separate powertrain families based on common calibration attributes. Group powertrains in the same powertrain family to the extent that powertrain test results and corresponding emission levels are expected to be similar throughout the useful life. (d) You may subdivide a group of powertrains with shared attributes under paragraph (b) of this section into different powertrain families. (e) In unusual circumstances, you may group powertrains into the same powertrain family even if they do not have shared attributes under in paragraph (b) of this section if you show that their emission characteristics throughout the useful life will be similar. (f) If you include the axle when performing powertrain testing for the family, you must limit the family to include only those axles represented by the test results. You may include multiple axle ratios in the family if you test with the axle expected to produce the highest emission results. [91 FR 7778, Feb. 18, 2026] § 1036.235 Testing requirements for certification. This section describes the emission testing you must perform to show compliance with the emission standards in § 1036.104 or fuel consumption standards under 49 CFR part 535. (a) Select and configure one or two emission-data engines from each engine family as follows: (1) You may use one engine for criteria pollutant testing and a different engine for fuel consumption testing, or you may use the same engine for all testing. (2) For criteria pollutant emission testing, select the engine configuration with the highest volume of fuel injected per cylinder per combustion cycle at the point of maximum torque—unless good engineering judgment indicates that a different engine configuration is more likely to exceed (or have emissions nearer to) an applicable emission standard or FEL. If two or more engines have the same fueling rate at maximum torque, select the one with the highest fueling rate at rated speed. In making this selection, consider all factors expected to affect emission-control performance and compliance with the standards, including emission levels of all exhaust constituents, especially NO X (3) For fuel consumption testing, the standards of this part apply only with respect to emissions measured from the tested configuration and other configurations identified in § 1036.205(l)(2). Note that configurations identified in § 1036.205(l)(2) are considered to be “tested configurations” whether or not you test them for certification. However, you must apply the same (or equivalent) emission controls to all other engine configurations in the engine family. In other contexts, the tested configuration is sometimes referred to as the “parent configuration”, although the terms are not synonymous. (4) In the case of powertrain testing under § 1036.545, select a test engine, test hybrid components, test axle and test transmission as applicable, by considering the whole range of vehicle models covered by the powertrain family. If the powertrain has more than one transmission calibration, for example economy vs. performance, you may weight the results from the powertrain testing in § 1036.545 by the percentage of vehicles in the family by prior model year for each configuration. This can be done, for example, through the use of survey data or based on the previous model year's sales volume. Weight the results of M fuel[cycle], f npowertrain v powertrain, W [cycle] (b) Test your emission-data engines using the procedures and equipment specified in subpart F of this part. In the case of dual-fuel and flexible-fuel engines, measure emissions when operating with each type of fuel for which you intend to certify the engine. (1) For criteria pollutant emission testing, measure NO X e CO2FTPFCL (2) For fuel consumption testing, measure CO 2 (i) For tractors, you must measure CO 2 (ii) For vocational applications, you must measure CO 2 (iii) For engine families that include both tractor and vocational use, you may submit CO 2 (iv) Some of your engines tested for use in tractors may also be used in vocational vehicles, and some of your engines tested for use in vocational may be used in tractors. However, you may not knowingly circumvent the intent of this part by testing engines designed for tractors or vocational vehicles (and rarely used in the other application) to the wrong cycle. (c) We may perform confirmatory testing by measuring emissions from any of your emission-data engines. If your certification includes powertrain testing as specified in § 1036.630, this paragraph (c) also applies for the powertrain test results. (1) We may decide to do the testing at your plant or any other facility. If we do this, you must deliver the engine to a test facility we designate. The engine you provide must include appropriate manifolds, aftertreatment devices, ECMs, and other emission-related components not normally attached directly to the engine block. If we do the testing at your plant, you must schedule it as soon as possible and make available the instruments, personnel, and equipment we need. (2) If we measure emissions on your engine, the results of that testing become the official emission results for the engine as specified in this paragraph (c). Unless we later invalidate these data, we may decide not to consider your data in determining if your engine family meets applicable requirements in this part. (3) Before we test one of your engines, we may set its adjustable parameters to any point within the practically adjustable ranges (see § 1036.115(f)). (4) Before we test one of your engines, we may calibrate it within normal production tolerances for anything we do not consider an adjustable parameter. For example, we may calibrate it within normal production tolerances for an engine parameter that is subject to production variability because it is adjustable during production, but is not considered an adjustable parameter because it is permanently sealed. For parameters that relate to a level of performance that is itself subject to a specified range (such as maximum power output), we will generally perform any calibration under this paragraph (c)(4) in a way that keeps performance within the specified range. (5) For fuel consumption testing, we may use our emission test results for steady-state, idle, cycle-average and powertrain fuel maps defined in § 1036.505(b) as the official emission results. We will not replace individual points from your fuel map. (i) We will determine fuel masses, m fuel[cycle], m fuelidle (ii) We will perform this comparison using the weighted results from GEM, using vehicles that are appropriate for the engine under test. For example, we may select vehicles that the engine went into for the previous model year. (iii) If you supply cycle-average engine fuel maps for the highway cruise cycles instead of generating a steady-state fuel map for these cycles, we may perform a confirmatory test of your engine fuel maps for the highway cruise cycles by either of the following methods: (A) Directly measuring the highway cruise cycle-average fuel maps. (B) Measuring a steady-state fuel map as described in this paragraph (c)(5) and using it in GEM to create our own cycle-average engine fuel maps for the highway cruise cycles. (iv) We will replace fuel maps as a result of confirmatory testing as follows: (A) Weight individual duty cycle results using the vehicle categories determined in paragraph (c)(5)(i) of this section and respective weighting factors in 40 CFR 1037.510(c) to determine a composite CO 2 (B) The average percent difference between fuel maps is calculated using the following equation: Where: i N e CO2compEPA i 2 i e CO2compManu i 2 i (C) Where the unrounded average percent difference between our composite weighted fuel map and the manufacturer's is at or below 0%, we will not replace the manufacturer's maps, and we will consider an individual engine to have passed the fuel map. (6) We may perform confirmatory testing with an engine dynamometer to simulate normal engine operation to determine whether your emission-data engine meets off-cycle emission standards. The accuracy margins described in § 1036.420(a) do not apply for such laboratory testing. (d) You may ask to use carryover emission data from a previous model year instead of doing new tests, but only if all the following are true: (1) The engine family from the previous model year differs from the current engine family only with respect to model year, items identified in § 1036.225(a), or other characteristics unrelated to emissions. We may waive this criterion for differences we determine not to be relevant. (2) The emission-data engine from the previous model year remains the appropriate emission-data engine under paragraph (a) of this section. (3) The data show that the emission-data engine would meet all the requirements that apply to the engine family covered by the application for certification. (e) We may require you to test a second engine of the same configuration in addition to the engines tested under paragraph (a) of this section. (f) If you use an alternate test procedure under 40 CFR 1065.10 and later testing shows that such testing does not produce results that are equivalent to the procedures specified in subpart F of this part, we may reject data you generated using the alternate procedure. (g) We may evaluate or test your engines to determine whether they have a defeat device before or after we issue a certificate of conformity. We may test or require testing on any vehicle or engine at a designated location, using driving cycles and conditions that may reasonably be expected in normal operation and use to investigate a potential defeat device. If we designate an engine's AECD as a possible defeat device, you must demonstrate to us that that the AECD does not reduce emission control effectiveness when the engine operates under conditions that may reasonably be expected in normal operation and use, unless one of the specific exceptions described in § 1036.115(h) applies. [91 FR 7778, Feb. 18, 2026] § 1036.240 Demonstrating compliance with criteria pollutant emission standards. (a) For purposes of certification, your engine family is considered in compliance with the duty-cycle emission standards in § 1036.104(a)(1) and (2) if all emission-data engines representing that family have test results showing official emission results and deteriorated emission levels at or below these standards (including all corrections and adjustments). This also applies for all test points for emission-data engines within the family used to establish deterioration factors. Note that your FELs are considered to be the applicable emission standards with which you must comply if you participate in the ABT program in subpart H of this part. Use good engineering judgment to demonstrate compliance with off-cycle standards throughout the useful life. (b) Your engine family is deemed not to comply if any emission-data engine representing that family has test results showing an official emission result or a deteriorated emission level for any pollutant that is above an applicable emission standard (including all corrections and adjustments). Similarly, your engine family is deemed not to comply if any emission-data engine representing that family has test results showing any emission level above the applicable off-cycle emission standard for any pollutant. This also applies for all test points for emission-data engines within the family used to establish deterioration factors. (c) To compare emission levels from the emission-data engine with the applicable duty-cycle emission standards, apply deterioration factors to the measured emission levels for each pollutant. Section 1036.245 specifies how to test engines and engine components to develop deterioration factors that represent the deterioration expected in emissions over your engines' useful life. Section 1036.246 describes how to confirm or modify deterioration factors based on in-use verification testing. Your deterioration factors must take into account any available data from other in-use testing with similar engines. Small manufacturers may use assigned deterioration factors that we establish. Apply deterioration factors as follows: (1) Additive deterioration factor for exhaust emissions. (2) Multiplicative deterioration factor for exhaust emissions. (3) Sawtooth and other nonlinear deterioration patterns. (4) Dual-fuel and flexible-fuel engines. (5) Deterioration factor for crankcase emissions. (d) Determine the official emission result for each pollutant to at least one more decimal place than the applicable standard. Apply the deterioration factor to the official emission result, as described in paragraph (c) of this section, then round the adjusted figure to the same number of decimal places as the emission standard. Compare the rounded emission levels to the emission standard for each emission-data engine. (e) You do not need deterioration factors to demonstrate compliance with off-cycle standards. However, for engines designed to discharge crankcase emissions to the ambient atmosphere, you must determine deteriorated emission levels to represent crankcase emissions at the end of useful life for purposes of demonstrating compliance with off-cycle emission standards. Determine an official brake-specific crankcase emission result for each pollutant based on operation over the FTP duty cycle. Also determine an official crankcase emission result for NO X [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29741, Apr. 22, 2024] § 1036.245 Deterioration factors for exhaust emission standards. This section describes how to determine deterioration factors, either with pre-existing test data or with new emission measurements. Apply these deterioration factors to determine whether your engines will meet the duty-cycle emission standards throughout the useful life as described in § 1036.240. The provisions of this section and the verification provisions of § 1036.246 apply for all engine families starting in model year 2027; you may optionally use these provisions to determine and verify deterioration factors for earlier model years. (a) You may ask us to approve deterioration factors for an engine family based on an engineering analysis of emission measurements from similar highway or nonroad engines if you have already given us these data for certifying the other engines in the same or earlier model years. Use good engineering judgment to decide whether the two engines are similar. We will approve your request if you show us that the emission measurements from other engines reasonably represent in-use deterioration for the engine family for which you have not yet determined deterioration factors. (b) [Reserved] (c) If you are unable to determine deterioration factors for an engine family under paragraph (a) of this section, select engines, subsystems, or components for testing. Determine deterioration factors based on service accumulation and related testing to represent the deterioration expected from in-use engines over the useful life, including crankcase emissions. You may perform maintenance on emission-data engines as described in § 1036.125 and 40 CFR part 1065, subpart E. Use good engineering judgment for all aspects of the effort to establish deterioration factors under this paragraph (c). Send us your test plan for our preliminary approval under § 1036.210. You may apply deterioration factors based on testing under this paragraph (c) to multiple engine families, consistent with the provisions in paragraph (a) of this section. Determine deterioration factors based on a combination of minimum required engine dynamometer aging hours and accelerated bench-aged aftertreatment as follows: (1) Select an emission-data engine and aftertreatment devices and systems that can be assembled into a certified configuration to represent the engine family. Stabilize the engine and aftertreatment devices and systems, together or separately, to prepare for emission measurements. Perform low-hour emission measurement once the engine has operated with aftertreatment long enough to stabilize the emission control. Measure emissions of all regulated pollutants while the engine operates over all applicable duty cycles on an engine dynamometer as described in subpart F of this part. (2) Perform additional service accumulation as described in paragraph (c)(3) of this section on an engine dynamometer meeting at least the following minimum specifications: Table 1 to Paragraph ( c Primary intended service class Minimum engine dynamometer hours Spark-ignition HDE 300 Light HDE 1,250 Medium HDE 1,500 Heavy HDE 1,500 (3) Perform service accumulation in the laboratory by operating the engine or hybrid powertrain repeatedly over one of the following test sequences, or a different test sequence that we approve in advance: (i) Use duty-cycle sequence 1 for operating any engine on an engine dynamometer, as follows: (A) Operate at idle for 2 hours. (B) Operate for 105 ± 1 hours over a repeat sequence of one FTP followed by one RMC. (C) Operate over one LLC. (D) Operate at idle for 2 hours. (E) Shut down the engine for cooldown to ambient temperature. (ii) Duty-cycle sequence 2 is based on operating over the LLC and the vehicle-based duty cycles from 40 CFR part 1037. Select the vehicle subcategory and vehicle configuration from § 1036.540 or § 1036.545 with the highest reference cycle work for each vehicle-based duty cycle. Operate the engine as follows for duty-cycle sequence 2: (A) Operate at idle for 2 hours. (B) Operate for 105 ± 1 hours over a repeat sequence of one Heavy-duty Transient Test Cycle, then one 55 mi/hr highway cruise cycle, and then one 65 mi/hr highway cruise cycle. (C) Operate over one LLC. (D) Operate at idle for 2 hours. (E) Shut down the engine for cooldown to ambient temperature. (4) Perform all the emission measurements described in paragraph (c)(1) of this section when the engine has reached the minimum service accumulation specified in paragraph (c)(2) of this section, and again after you finish service accumulation in the laboratory if your service accumulation exceeds the values specified in paragraph (c)(2) of this section. (5) Determine the deterioration factor based on a combination of actual and simulated service accumulation represented by a number of hours of engine operation calculated using the following equation: Where: UL k v agingcycle Example for Heavy HDE for Duty-Cycle Sequence 1: UL k v agingcycle t total (6) Perform accelerated bench aging of aftertreatment devices to represent normal engine operation over the useful life using the service accumulation hours determined in paragraph (c)(5) of this section. Design your bench aging to represent 10,000 hours of in-use engine operation for every 1,000 hours of accelerated bench aging. Use the accelerated bench-aging procedure in 40 CFR 1065.1131 through 1065.1145 or get our advance approval to use a different procedure that adequately that accounts for thermal and chemical degradation. For example, this might involve testing consistent with the analogous procedures that apply for light-duty vehicles under 40 CFR part 86, subpart S. (7) After bench-aging aftertreatment devices, install or reinstall those aftertreatment devices and systems on an emission-data engine (or an equivalent engine) that has been stabilized without aftertreatment. Ensure that the aftertreatment is installed such that the engine is in a certified configuration to represent the engine family. (8) Operate the engine with the bench-aged aftertreatment devices to stabilize emission controls for at least 100 hours on an engine dynamometer. (9) Once stabilization is complete, repeat the low-hour emission measurements. (10) Calculate deterioration factors by comparing exhaust emissions with the bench-aged aftertreatment and exhaust emissions at the low-hour test point. Create a linear curve fit if testing includes intermediate test points. Calculate deterioration factors based on measured values, without extrapolation. (d) If you determine deterioration factors as described in paragraph (c) of this section, you may apply those deterioration factors in later years for engine families that qualify for carryover certification as described in § 1036.235(d). You may also apply those deterioration factors for additional engine families as described in paragraph (a) of this section. (e) Include the following information in your application for certification: (1) If you use test data from a different engine family, explain why this is appropriate and include all the emission measurements on which you base the deterioration factors. If the deterioration factors for the new engine family are not identical to the deterioration factors for the different engine family, describe your engineering analysis to justify the revised values and state that all your data, analyses, evaluations, and other information are available for our review upon request. (2) If you determined deterioration factors under paragraph (c) of this section, include the following information in the first year that you use those deterioration factors: (i) Describe your accelerated bench aging or other procedures to represent full-life service accumulation for the engine's emission controls. (ii) Describe how you prepared the test engine before and after installing aftertreatment systems to determine deterioration factors. (iii) Identify the power rating of the emission-data engine used to determine deterioration factors. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29742, Apr. 22, 2024] § 1036.246 Verifying deterioration factors. We may require you to test in-use engines as described in this section to verify that the deterioration factors you determined under § 1036.245 are appropriate. (a) Select and prepare in-use engines representing the engine family we identify for verification testing under this section as follows: (1) You may recruit candidate engines any time before testing. This may involve creating a pool of candidate engines and vehicles in coordination with vehicle manufacturers and vehicle purchasers to ensure availability and to confirm a history of proper maintenance. You may meet the testing requirements of this section by repeating tests on a given engine as it ages, or you may test different engines over the course of verification testing; however, you may not choose whether to repeat tests on a given engine at a later stage based on its measured emission levels. We generally require that you describe your plan for selecting engines in advance and justify any departures from that plan. (2) Selected vehicles must come from independent sources, unless we approve your request to select vehicles that you own or manage. In your request, you must describe how you will ensure that the vehicle operator will drive in a way that represents normal in-use operation for the engine family. (3) Select vehicles with installed engines from the same engine family and with the same power rating as the emission-data engine used to determine the deterioration factors. However, if the test engine does not have the specified power rating, you may ask for our approval to either test in the as-received condition or modify engines in selected vehicles by reflashing the ECM or replacing parts to change the engines to be in a different certified configuration for proper testing. (4) Selected engines must meet the screening criteria described in § 1036.410(b)(2) through (4). Selected engines must also have their original aftertreatment components and be in a certified configuration. You may ask us to approve replacing a critical emission-related component with an equivalent part that has undergone a comparable degree of aging. (5) We may direct you to preferentially select certain types of vehicles, vehicles from certain model years. or vehicles within some range of service accumulation. We will not direct you to select vehicles that are 10 or more years old, or vehicles with an odometer reading exceeding 85 percent of the engine's useful life. We will specify a time frame for completing required testing. (b) Perform verification testing with one of the following procedures, or with an alternative procedure that you demonstrate to be equally effective: (1) Engine dynamometer testing. (i) Test the aftertreatment system from at least two engines using the procedures specified in subpart F of this part and 40 CFR part 1065. Install the aftertreatment system from the selected in-use vehicle, including all associated wiring, sensors, and related hardware and software, on one of the following partially complete engines: (A) The in-use engine from the same vehicle. (B) The emission-data engine used to determine the deterioration factors. (C) A different emission-data engine from the same engine family that has been stablized as described in 40 CFR 1065.405(c). (ii) Perform testing on all certification duty cycles with brake-specific emission standards (g/hp·hr) to determine whether the engine meets all the duty-cycle emission standards, including any compliance allowance, for criteria pollutants. Apply infrequent regeneration adjustment factors as included in your application for certification or develop new factors if we request it. (iii) Evaluate verification testing for each pollutant independently. You pass the verification test if at least 70 percent of tested engines meet standards for each pollutant over all duty cycles. You fail the verification test if fewer than 70 percent of engines meet standards for a given pollutant over all duty cycles. (2) PEMS testing. (i) Test at least five engines using the procedures specified in § 1036.555 and 40 CFR part 1065, subpart J. (ii) Measure emissions of NO X (iii) Evaluate verification testing for each pollutant independently. You pass the verification test if at least 70 percent of tested engines meet the off-cycle standards including any compliance allowance and accuracy margin, for each pollutant. You fail the verification test if fewer than 70 percent of tested engines do not meet standards for a given pollutant. (iv) You may reverse a fail determination under paragraph (b)(2)(iii) of this section by restarting and successfully completing the verification test for that year using the procedures specified in paragraph (b)(1) of this section. If you do this, you must use the verification testing procedures specified in paragraph (b)(1) of this section for all remaining verification testing for the engine family. (c) You may stop testing under the verification test program and concede a fail result before you meet all the testing requirements of this section. (d) Prepare a report to describe your verification testing each year. Include at least the following information: (1) Identify whether you tested using the procedures specified in paragraph (b)(1) or (2) of this section. (2) Describe how the test results support a pass or fail decision for the verification test. For in-field measurements, include continuous 1 Hz data collected over the shift-day and binned emission values determined under § 1036.530. (3) If your testing included invalid test results, describe the reasons for invalidating the data. Give us the invalid test results if we ask for them. (4) Describe the types of vehicles selected for testing. If you determined that any selected vehicles with enough mileage accumulation were not suitable for testing, describe why you chose not to test them. (5) For each tested engine, identify the vehicle's VIN, the engine's serial number, the engine's power rating, and the odometer reading and the engine's lifetime operating hours at the start of testing (or engine removal). (6) State that the tested engines have been properly maintained and used and describe any noteworthy aspects of each vehicle's maintenance history. Describe the steps you took to prepare the engines for testing. (7) For testing with engines that remain installed in vehicles, identify the date and location of testing. Also describe the ambient conditions and the driving route over the course of the shift-day. (e) Send electronic reports to the Designated Compliance Officer using an approved information format. If you want to use a different format, send us a written request with justification. (1) You may send us reports as you complete testing for an engine instead of waiting until you complete testing for all engines. (2) We may ask you to send us less information in your reports than we specify in this section. (3) We may require you to send us more information to evaluate whether your engine family meets the requirements of this part. (4) Once you send us information under this section, you need not send that information again in later reports. (5) We will review your test report to evaluate the results of the verification testing at each stage. We will notify you if we disagree with your conclusions, if we need additional information, or if you need to revise your testing plan for future testing. § 1036.250 Reporting and recordkeeping for certification. (a) By September 30 following the end of the model year, send the Designated Compliance Officer a report including the total U.S.-directed production volume of engines you produced in each engine family during the model year (based on information available at the time of the report). Report the production by serial number and engine configuration. You may combine this report with reports required under subpart H of this part. We may waive the reporting requirements of this paragraph (a) for small manufacturers. (b) Organize and maintain the following records: (1) A copy of all applications and any summary information you send us. (2) Any of the information we specify in § 1036.205 that you were not required to include in your application. (3) A detailed history of each emission-data engine. For each engine, describe all of the following: (i) The emission-data engine's construction, including its origin and buildup, steps you took to ensure that it represents production engines, any components you built specially for it, and all the components you include in your application for certification. (ii) How you accumulated engine operating hours (service accumulation), including the dates and the number of hours accumulated. (iii) All maintenance, including modifications, parts changes, and other service, and the dates and reasons for the maintenance. (iv) All your emission tests, including documentation on routine and standard tests, as specified in part 40 CFR part 1065, and the date and purpose of each test. (v) All tests to diagnose engine or emission control performance, giving the date and time of each and the reasons for the test. (vi) Any other significant events. (4) Production figures for each engine family divided by assembly plant. (5) Engine identification numbers for all the engines you produce under each certificate of conformity. (c) Keep routine data from emission tests required by this part (such as test cell temperatures and relative humidity readings) for one year after we issue the associated certificate of conformity. Keep all other information specified in this section for eight years after we issue your certificate. (d) Store these records in any format and on any media, as long as you can promptly send us organized, written records in English if we ask for them. You must keep these records readily available. We may review them at any time. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29742, Apr. 22, 2024] § 1036.255 EPA oversight on certificates of conformity. (a) If we determine an application is complete and shows that the engine family meets all the requirements of this part and the Act, we will issue a certificate of conformity for the engine family for that model year. We may make the approval subject to additional conditions. (b) We may deny an application for certification if we determine that an engine family fails to comply with emission standards or other requirements of this part or the Clean Air Act. We will base our decision on all available information. If we deny an application, we will explain why in writing. (c) In addition, we may deny your application or suspend or revoke a certificate of conformity if you do any of the following: (1) Refuse to comply with any testing or reporting requirements in this part. (2) Submit false or incomplete information. This includes doing anything after submitting an application that causes submitted information to be false or incomplete. (3) Cause any test data to become inaccurate. (4) Deny us from completing authorized activities (see 40 CFR 1068.20). This includes a failure to provide reasonable assistance. (5) Produce engines for importation into the United States at a location where local law prohibits us from carrying out authorized activities. (6) Fail to supply requested information or amend an application to include all engines being produced. (7) Take any action that otherwise circumvents the intent of the Act or this part. (d) We may void a certificate of conformity if you fail to keep records, send reports, or give us information as required under this part or the Act. Note that these are also violations of 40 CFR 1068.101(a)(2). (e) We may void a certificate of conformity if we find that you intentionally submitted false or incomplete information. This includes doing anything after submitting an application that causes submitted information to be false or incomplete after submission. (f) If we deny an application or suspend, revoke, or void a certificate, you may ask for a hearing (see § 1036.820). Subpart D—Testing Production Engines and Hybrid Powertrains § 1036.301 Selective enforcement audits. (a) Selective enforcement audits apply for engines as specified in 40 CFR part 1068, subpart E. This section describes how this applies uniquely in certain circumstances. (b) Selective enforcement audit provisions apply with respect to your fuel maps as follows: (1) A selective enforcement audit for an engine with respect to fuel maps would consist of performing measurements with production engines to determine fuel-consumption rates as declared for GEM simulations, and running GEM for the vehicle configurations specified in paragraph (b)(2) of this section based on those measured values. The engine is considered passing for a given configuration if the new modeled emission result for each applicable duty cycle is at or below the modeled emission result corresponding to the declared GEM inputs. The engine is considered failing if we determine that its fuel map result is above the modeled emission result corresponding to the result using the manufacturer-declared fuel maps, as specified in § 1036.235(c)(5). (2) If the audit includes fuel-map testing in conjunction with engine testing relative to exhaust emission standards, the fuel-map simulations for the whole set of vehicles and duty cycles counts as a single test result for purposes of evaluating whether the engine family meets the pass-fail criteria under 40 CFR 1068.420. (c) If your certification includes powertrain testing as specified in § 1036.630, these selective enforcement audit provisions apply with respect to powertrain test results as specified in § 1036.545 and 40 CFR part 1037, subpart D. We may allow manufacturers to instead perform the engine-based testing to simulate the powertrain test as specified in 40 CFR 1037.551. (d) We may suspend or revoke certificates for any appropriate configurations within one or more engine families based on the outcome of a selective enforcement audit. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29742, Apr. 22, 2024] Subpart E—In-Use Testing § 1036.401 Testing requirements for in-use engines. (a) We may perform in-use testing of any engine family subject to the standards of this part, consistent with the Clean Air Act and the provisions of § 1036.235. (b) This subpart describes a manufacturer-run field-testing program that applies for engines subject to compression-ignition standards under § 1036.104. Note that the testing requirements of 40 CFR part 86, subpart T, continue to apply for engines subject to exhaust emission standards under 40 CFR part 86. (c) In-use test procedures for engines subject to spark-ignition standards apply as described in § 1036.530. We won't require routine manufacturer-run field testing for Spark-ignition HDE, but the procedures of this subpart describe how to use field-testing procedures to measure emissions from engines installed in vehicles. Use good engineering judgment to apply the measurement procedures for fuels other than gasoline. (d) We may void your certificate of conformity for an engine family if you do not meet your obligations under this subpart. We may also void individual tests and require you to retest those vehicles or take other appropriate measures in instances where you have not performed the testing in accordance with the requirements described in this subpart. § 1036.405 Overview of the manufacturer-run field-testing program. (a) You must test in-use engines from the families we select. We may select the following number of engine families for testing, except as specified in paragraph (b) of this section: (1) We may select up to 25 percent of your engine families in any calendar year, calculated by dividing the number of engine families you certified in the model year corresponding to the calendar year by four and rounding to the nearest whole number. We will consider only engine families with annual U.S.-directed production volumes above 1,500 units in calculating the number of engine families subject to testing each calendar year under the annual 25 percent engine family limit. If you have only three or fewer families that each exceed an annual U.S.-directed production volume of 1,500 units, we may select one engine family per calendar year for testing. (2) Over any four-year period, we will not select more than the average number of engine families that you have certified over that four-year period (the model year when the selection is made and the preceding three model years), based on rounding the average value to the nearest whole number. (3) We will not select engine families for testing under this subpart from a given model year if your total U.S.-directed production volume was less than 100 engines. (b) If there is clear evidence of a nonconformity with regard to an engine family, we may select that engine family without counting it as a selected engine family under paragraph (a) of this section. For example, there may be clear evidence of a nonconformity if you certify an engine family using carryover data after reaching a fail decision under this subpart in an earlier model year without modifying the engine to remedy the problem. (c) We may select any individual engine family for testing, regardless of its production volume except as described in paragraph (a)(3) of this section, as long as we do not select more than the number of engine families described in paragraph (a) of this section. We may select an engine family from model year 2027 or any later model year. (d) You must complete all the required testing and reporting under this subpart (for all ten test engines, if applicable), within 18 months after we direct you to test a particular engine family. We will typically select engine families for testing and notify you in writing by June 30 of the applicable calendar year. If you request it, we may allow additional time to send us this information. (e) If you make a good-faith effort to access enough test vehicles to complete the testing requirements under this subpart for an engine family, but are unable to do so, you must ask us either to modify the testing requirements for the selected engine family or to select a different engine family. (f) We may select an engine family for repeat testing in a later calendar year. Such a selection for repeat testing would count as an additional engine family for that year under paragraph (a) of this section. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29742, Apr. 22, 2024] § 1036.410 Selecting and screening vehicles and engines for testing. (a) Send us your proposed plan for recruiting, screening, and selecting vehicles. Identify the types of vehicles, location, and any other relevant criteria. We will approve your plan if it supports the objective of measuring emissions to represent a broad range of operating characteristics. (b) Select vehicles and engines for testing that meet the following criteria: (1) The vehicles come from at least two independent sources. (2) Powertrain, drivetrain, emission controls, and other key vehicle and engine systems have been properly maintained and used. See § 1036.125. (3) The engines have not been tampered with, rebuilt, or undergone major repair that could be expected to affect emissions. (4) The engines have not been misfueled. Do not consider engines misfueled if they have used fuel meeting the specifications of § 1036.415(c). (5) The vehicles are likely to operate for at least three hours of non-idle operation over a complete shift-day, as described in § 1036.415(f). (6) The vehicles have not exceeded the applicable useful life, in miles, hours, or years; you may otherwise not exclude engines from testing based on their age or mileage. (7) The vehicle has appropriate space for safe and proper mounting of the portable emission measurement system (PEMS) equipment. (c) You must notify us before disqualifying any vehicle based on illuminated MIL or stored OBD trouble codes as described in § 1036.415(b)(2), or for any other reasons not specified in paragraph (b) of this section. For example, notify us if you disqualify any vehicle because the engine does not represent the engine family or the vehicle's usage is atypical for the particular application. You do not need to notify us in advance if the owner declines to participate in the test program. § 1036.415 Preparing and testing engines. (a) You must limit maintenance to what is in the owners manual for engines with that amount of service and age. For anything we consider an adjustable parameter (see § 1036.115(f)), you may adjust that parameter only if it is outside its adjustable range. You must then set the adjustable parameter to your recommended setting or the mid-point of its adjustable range, unless we approve your request to do otherwise. You must get our approval before adjusting anything not considered an adjustable parameter. You must keep records of all maintenance and adjustments, as required by § 1036.435. You must send us these records, as described in § 1036.430(a)(2)(ix), unless we instruct you not to send them. (b) You may treat a vehicle with an illuminated MIL or stored trouble code as follows: (1) If a candidate vehicle has an illuminated MIL or stored trouble code, either test the vehicle as received or repair the vehicle before testing. Once testing is initiated on the vehicle, you accept that the vehicle has been properly maintained and used. (2) If a MIL illuminates or a trouble code appears on a test vehicle during a field test, stop the test and repair the vehicle. Determine test results as specified in § 1036.530 using one of the following options: (i) Restart the testing and use only the portion of the full test results without the MIL illuminated or trouble code set. (ii) Initiate a new test and use only the post-repair test results. (3) If you determine that repairs are needed but they cannot be completed in a timely manner, you may disqualify the vehicle and replace it with another vehicle. (c) Use appropriate fuels for testing, as follows: (1) You may use any diesel fuel that meets the specifications for S15 in ASTM D975 (incorporated by reference, see § 1036.810). You may use any commercially available biodiesel fuel blend that meets the specifications for ASTM D975 or ASTM D7467 (incorporated by reference, see § 1036.810) that is either expressly allowed or not otherwise indicated as an unacceptable fuel in the vehicle's owner or operator manual or in the engine manufacturer's published fuel recommendations. You may use any gasoline fuel that meets the specifications in ASTM D4814 (incorporated by reference, see § 1036.810). For other fuel types, you may use any commercially available fuel. (2) You may drain test vehicles' fuel tanks and refill them with diesel fuel conforming to the specifications in paragraph (c)(1) of this section. (3) Any fuel that is added to a test vehicle's fuel tanks must be purchased at a local retail establishment near the site of vehicle recruitment or screening, or along the test route. Alternatively, the fuel may be drawn from a central fueling source, as long as the fuel represents commercially available fuel in the area of testing. (4) No post-refinery fuel additives are allowed, except that specific fuel additives may be used during field testing if you can document that the test vehicle has a history of normally using the fuel treatments and they are not prohibited in the owners manual or in your published fuel-additive recommendations. (5) You may take fuel samples from test vehicles to ensure that appropriate fuels were used during field testing. If a vehicle fails the vehicle-pass criteria and you can show that an inappropriate fuel was used during the failed test, that particular test may be voided. You may drain vehicles' fuel tanks and refill them with diesel fuel conforming to the specifications described in paragraph (c)(1) of this section. You must report any fuel tests that are the basis of voiding a test in your report under § 1036.430. (d) You must test the selected engines using the test procedure described in § 1036.530 while they remain installed in the vehicle. Testing consists of characterizing emission rates for moving average 300 second windows while driving, with those windows divided into bins representing different types of engine operation over a shift-day. Measure emissions as follows: (1) Perform all testing with PEMS and field-testing procedures referenced in 40 CFR part 1065, subpart J. Measure emissions of NO X 2 (2) If the engine's crankcase discharges emissions into the ambient atmosphere, as allowed by § 1036.115(a), you must either route all crankcase emissions into the exhaust for a combined measurement or add the crankcase emission values specified in § 1036.240(e) to represent emission levels at full useful life instead of measuring crankcase emissions in the field. (e) Operate the test vehicle under conditions reasonably expected during normal operation. For the purposes of this subpart, normal operation generally includes the vehicle's normal routes and loads (including auxiliary loads such as air conditioning in the cab), normal ambient conditions, and the normal driver. (f) Once an engine is set up for testing, test the engine for one shift-day, except as allowed in § 1036.420(d). To complete a shift-day's worth of testing, start sampling at the beginning of a shift and continue sampling for the whole shift, subject to the calibration requirements of the PEMS. A shift-day is the period of a normal workday for an individual employee. Evaluate the emission data as described in § 1036.420 and include the data in the reporting and record keeping requirements specified in §§ 1036.430 and 1036.435. (g) For stop-start and automatic engine shutdown systems meeting the specifications of 40 CFR 1037.660, override idle-reduction features if they are adjustable under 40 CFR 1037.520(j)(4). If those systems are tamper-resistant under 40 CFR 1037.520(j)(4), set the 1-Hz emission rate to zero for all regulated pollutants when the idle-reduction feature is active. Do not exclude these data points under § 1036.530(c)(3)(ii). [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29742, Apr. 22, 2024] § 1036.420 Pass criteria for individual engines. Perform the following steps to determine whether an engine meets the binned emission standards in § 1036.104(a)(3): (a) Determine the emission standard for each regulated pollutant for each bin by adding the following accuracy margins for PEMS to the off-cycle standards in § 1036.104(a)(3): Table 1 to Paragraph ( a NO X HC PM CO Bin 1 0.4 g/hr Bin 2 5 mg/hp·hr 10 mg/hp·hr 6 mg/hp·hr 0.25 g/hp·hr. (b) Calculate the mass emission rate for each pollutant as specified in § 1036.530. (c) For engines subject to compression-ignition standards, determine the number of windows in each bin. A bin is valid under this section only if it has at least 2,400 windows for bin 1 and 10,000 windows for bin 2. (d) Continue testing additional shift-days as necessary to achieve the minimum window requirements for each bin. You may idle the engine at the end of the shift day to increase the number of windows in bin 1. If the vehicle has tamper-resistant idle-reduction technology that prevents idling, populate bin 1 with additional windows by setting the 1-Hz emission rate for all regulated pollutants to zero as described in § 1036.415(g) to achieve exactly 2,400 bin 1 windows. (e) An engine passes if the result for each bin is at or below the standard determined in paragraph (a) of this section. An engine fails if the result for any bin for any pollutant is above the standard determined in paragraph (a) of this section. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29742, Apr. 22, 2024] § 1036.425 Pass criteria for engine families. For testing with PEMS under § 1036.415(d)(1), determine the number of engines you must test from each selected engine family and the family pass criteria as follows: (a) Start by measuring emissions from five engines using the procedures described in this subpart E and § 1036.530. If all five engines comply fully with the off-cycle bin standards, the engine family passes, and you may stop testing. (b) If only one of the engines tested under paragraph (a) of this section does not comply fully with the off-cycle bin standards, test one more engine. If this additional engine complies fully with the off-cycle bin standards, the engine family passes, and you may stop testing. (c) If two or more engines tested under paragraphs (a) and (b) of this section do not comply fully with the off-cycle bin standards, test additional engines until you have tested a total of ten engines. Calculate the arithmetic mean of the bin emissions from the ten engine tests as specified in § 1036.530(g) for each pollutant. If the mean values are at or below the off-cycle bin standards, the engine family passes. If the mean value for any pollutant is above an off-cycle bin standard, the engine family fails. (d) You may accept a fail result for the engine family and discontinue testing at any point in the sequence of testing the specified number of engines. § 1036.430 Reporting requirements. (a) Report content. (1) Include the following for each engine family: (i) Describe how you recruited vehicles. Describe how you used any criteria or thresholds to narrow your search or to screen individual vehicles. (ii) Include a summary of the vehicles you have disqualified and the reasons you disqualified them, whether you base the disqualification on the criteria in § 1036.410(b), owner nonparticipation, or anything else. If you disqualified a vehicle due to misfueling, include the results of any fuel sample tests. If you reject a vehicle due to tampering, describe how you determined that tampering occurred. (iii) Identify how many engines you have tested from the applicable engine family and how many engines still need to be tested. Identify how many tested engines have passed or failed under § 1036.420. (iv) After the final test, report the results and state the outcome of testing for the engine family based on the criteria in § 1036.425. (v) Describe any incomplete or invalid tests that were conducted under this subpart. (2) Include the following information for the test vehicle: (i) The EPA engine-family designation, and the engine's model number, total displacement, and power rating. (ii) The date EPA selected the engine family for testing. (iii) The vehicle's make and model and the year it was built. (iv) The vehicle identification number and engine serial number. (v) The vehicle's type or application (such as delivery, line haul, or dump truck). Also, identify the type of trailer, if applicable. (vi) The vehicle's maintenance and use history. (vii) The known status history of the vehicle's OBD system and any actions taken to address OBD trouble codes or MIL illumination over the vehicle's lifetime. (viii) Any OBD codes or MIL illumination that occur after you accept the vehicle for field testing under this subpart. (ix) Any steps you take to maintain, adjust, modify, or repair the vehicle or its engine to prepare for or continue testing, including actions to address OBD trouble codes or MIL illumination. Include any steps you took to drain and refill the vehicle's fuel tank(s) to correct misfueling, and the results of any fuel test conducted to identify misfueling. (3) Include the following data and measurements for each test vehicle: (i) The date and time of testing, and the test number. (ii) Number of shift-days of testing (see § 1036.415(f)). (iii) Route and location of testing. You may base this description on the output from a global-positioning system (GPS). (iv) The steps you took to ensure that vehicle operation during testing was consistent with normal operation and use, as described in § 1036.415(e). (v) Fuel test results, if fuel was tested under § 1036.410 or § 1036.415. (vi) The vehicle's mileage at the start of testing. Include the engine's total lifetime hours of operation, if available. (vii) The number of windows in each bin (see § 1036.420(c)). (viii) The bin emission value per vehicle for each pollutant. Describe the method you used to determine HC as specified in 40 CFR 1065.660(b). (ix) Recorded 1 Hz test data for at least the following parameters, noting that gaps in the 1 Hz data file over the shift-day are only allowed during analyzer zero and span verifications and during engine shutdown when the engine is keyed off: (A) Ambient temperature. (B) Ambient pressure. (C) Ambient humidity. (D) Altitude. (E) Emissions of HC, CO, CO 2 X (F) Differential backpressure of any PEMS attachments to vehicle exhaust. (G) Exhaust flow. (H) Exhaust aftertreatment temperatures. (I) Engine speed. (J) Engine brake torque. (K) Engine coolant temperature (L) Intake manifold temperature. (M) Intake manifold pressure. (N) Throttle position. (O) Any parameter sensed or controlled, available over the Controller Area Network (CAN) network, to modulate the emission control system or fuel-injection timing. (4) Include the following summary information after you complete testing with each engine: (i) State whether the engine meets the off-cycle standards for each bin for each pollutant as described in § 1036.420(e). (ii) Describe if any testing or evaluations were conducted to determine why a vehicle failed the off-cycle emission standards described in § 1036.420. (iii) Describe the purpose of any diagnostic procedures you conduct. (iv) Describe any instances in which the OBD system illuminated the MIL or set trouble codes. Also describe any actions taken to address the trouble codes or MIL. (v) Describe any instances of misfueling, the approved actions taken to address the problem, and the results of any associated fuel sample testing. (vi) Describe the number and length of any data gaps in the 1 Hz data file, the reason for the gap(s), and the parameters affected. (b) Submission. (1) You may send us reports as you complete testing for an engine instead of waiting until you complete testing for all engines. (2) We may ask you to send us less information in your reports than we specify in this section. (3) We may require you to send us more information to evaluate whether your engine family meets the requirements of this part. (4) Once you send us information under this section, you need not send that information again in later reports. (c) Additional notifications. (1) Notify us once you complete testing for an engine. (2) Notify us if your review of the test data for an engine family indicates that two of the first five tested engines have failed to comply with the vehicle-pass criteria in § 1036.420(e). (3) Notify us if your review of the test data for an engine family indicates that the engine family does not comply with the family-pass criteria in § 1036.425(c). (4) Describe any voluntary vehicle/engine emission evaluation testing you intend to conduct with PEMS on the same engine families that are being tested under this subpart, from the time that engine family was selected for field testing under § 1036.405 until the final results of all testing for that engine family are reported to us under this section. § 1036.435 Recordkeeping requirements. Keep the following paper or electronic records of your field testing for five years after you complete all the testing required for an engine family: (a) Keep a copy of the reports described in § 1036.430. (b) Keep any additional records, including forms you create, related to any of the following: (1) The recruitment, screening, and selection process described in § 1036.410, including the vehicle owner's name, address, phone number, and email address. (2) Pre-test maintenance and adjustments to the engine performed under § 1036.415. (3) Test results for all void, incomplete, and voluntary testing described in § 1036.430. (4) Evaluations to determine why an engine failed any of the bin standards described in § 1036.420. (c) Keep a copy of the relevant calibration results required by 40 CFR part 1065. § 1036.440 Warranty obligations related to in-use testing. Testing under this subpart that finds an engine exceeding emission standards under this subpart is not by itself sufficient to show a breach of warranty under 42 U.S.C. 7541(a)(1). A breach of warranty would also require that engines fail to meet one or both of the conditions specified in § 1036.120(a). Subpart F—Test Procedures § 1036.501 General testing provisions. (a) Use the equipment and procedures specified in this subpart and 40 CFR part 1065 to determine whether engines meet the emission standards in § 1036.104 or fuel consumption standards under 49 CFR part 535. (b) Use the fuels specified in 40 CFR part 1065 to perform valid tests, as follows: (1) For service accumulation, use the test fuel or any commercially available fuel that is representative of the fuel that in-use engines will use. (2) For diesel-fueled engines, use the ultra-low-sulfur diesel fuel specified in 40 CFR part 1065.703 and 40 CFR 1065.710(b)(3) for emission testing. (3) For gasoline-fueled engines, use the appropriate E10 fuel specified in 40 CFR part 1065. (c) For engines that use aftertreatment technology with infrequent regeneration events, apply infrequent regeneration adjustment factors for each duty cycle as described in § 1036.580. (d) If your engine is intended for installation in a vehicle equipped with stop-start technology meeting the specifications of 40 CFR 1037.660 to qualify as tamper-resistant under 40 CFR 1037.520(j)(4), you may shut the engine down during idle portions of the duty cycle to represent in-use operation. We recommend installing a production engine starter motor and letting the engine's ECM manipulate the starter motor to control the engine stop and start events. Use good engineering judgment to address the effects of dynamometer inertia on restarting the engine by, for example, using a larger starter motor or declutching the engine from the dynamometer during restart. (e) You may disable any AECDs that have been approved solely for emergency equipment applications under § 1036.115(h)(4). Note that the emission standards do not apply when any of these AECDs are active. (f) You may use special or alternate procedures to the extent we allow them under 40 CFR 1065.10. (g) This subpart is addressed to you as a manufacturer, but it applies equally to anyone who does testing for you, and to us when we perform testing to determine if your engines meet emission standards. (h) For testing engines that use regenerative braking through the crankshaft only to power an electric heater for aftertreatment devices, you may use the nonhybrid engine testing procedures in §§ 1036.510, 1036.512, and 1036.514 and you may also or instead use the fuel mapping procedure in § 1036.505(b)(1) or (2). You may use this allowance only if the recovered energy is less than 10 percent of the total positive work for each applicable test interval. Otherwise, use powertrain testing procedures specified for hybrid powertrains to measure emissions and create fuel maps. For engines that power an electric heater with a battery, you must meet the requirements related to charge-sustaining operation as described in 40 CFR 1066.501(a)(3). [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29742, Apr. 22, 2024; 91 FR 7779, Feb. 18, 2026] § 1036.503 Engine data and information to support vehicle certification for NHTSA. See § 1036.505 for engine data and information required to support vehicle certification. [91 FR 7779, Feb. 18, 2026] § 1036.505 Engine data and information to support vehicle certification. You must give vehicle manufacturers information as follows so they can certify their vehicles to fuel consumption standards under 49 CFR part 535: (a) Identify engine make, model, fuel type, combustion type, engine family name, calibration identification, and engine displacement. Also identify whether the engines will be used in tractors, vocational vehicles, or both. When certifying vehicles with GEM, for any fuel type not identified in table 1 to paragraph (b)(4) of § 1036.550, identify the fuel type as diesel fuel for engines subject to compression-ignition standards, and as gasoline for engines subject to spark-ignition standards. (b) This paragraph (b) describes four different methods to generate engine fuel maps. For engines without hybrid components and for mild hybrid engines where you do not include hybrid components in the test, generate fuel maps using either paragraph (b)(1) or (2) of this section. For other hybrid engines, generate fuel maps using paragraph (b)(3) of this section. For hybrid powertrains and nonhybrid powertrains and for vehicles where the transmission is not automatic, automated manual, manual, or dual-clutch, generate fuel maps using paragraph (b)(4) of this section. (1) Determine steady-state engine fuel maps as described in § 1036.535(b). Determine fuel consumption at idle as described in § 1036.535(c). Determine cycle-average engine fuel maps as described in § 1036.540, excluding cycle-average fuel maps for highway cruise cycles. (2) Determine steady-state fuel maps as described in either § 1036.535(b) or (d). Determine fuel consumption at idle as described in § 1036.535(c). Determine cycle-average engine fuel maps as described in § 1036.540, including cycle-average engine fuel maps for highway cruise cycles. We may do confirmatory testing by creating cycle-average fuel maps from steady-state fuel maps created in paragraph (b)(1) of this section for highway cruise cycles. In § 1036.540 we define the vehicle configurations for testing; we may add more vehicle configurations to better represent your engine's operation for the range of vehicles in which your engines will be installed (see 40 CFR 1065.10(c)(1)). (3) Determine fuel consumption at idle as described in § 1036.535(c) and (d) and determine cycle-average engine fuel maps as described in § 1036.545, including cycle-average engine fuel maps for highway cruise cycles. Set up the test to apply accessory load for all operation by primary intended service class as described in the following table: Table 1 to Paragraph ( b Primary intended service class Power representing accessory load Light HDV 1.5 Medium HDV 2.5 Heavy HDV 3.5 (4) Generate powertrain fuel maps as described in § 1036.545 instead of fuel mapping under § 1036.535 or § 1036.540. Note that the option in § 1036.545(b)(2) is allowed only for hybrid engine testing. Disable stop-start systems and automatic engine shutdown systems when conducting powertrain fuel map testing using § 1036.545. (c) Provide the following information if you generate engine fuel maps using either paragraph (b)(1), (2), or (3) of this section: (1) Full-load torque curve for installed engines and the full-load torque curve of the engine (parent engine) with the highest fueling rate that shares the same engine hardware, including the turbocharger, as described in 40 CFR 1065.510. You may use 40 CFR 1065.510(b)(5)(i) for Spark-ignition HDE. Measure the torque curve for hybrid engines that have an RESS as described in 40 CFR 1065.510(g)(2) with the hybrid system active. Test hybrid engines with no RESS as described in 40 CFR 1065.510(b)(5)(ii). (2) Motoring torque curve as described in 40 CFR 1065.510(c)(2) and (5) for nonhybrid and hybrid engines, respectively. For engines with a low-speed governor, remove data points where the low-speed governor is active. If you don't know when the low-speed governor is active, we recommend removing all points below 40 r/min above the warm low-idle speed. (3) Declared engine idle speed. For vehicles with manual transmissions, this is the engine speed with the transmission in neutral. For all other vehicles, this is the engine's idle speed when the transmission is in drive. (4) The engine idle speed during the transient cycle-average fuel map. (5) The engine idle torque during the transient cycle-average fuel map. (d) If you generate powertrain fuel maps using paragraph (b)(4) of this section, determine the system continuous rated power according to § 1036.520. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29743, Apr. 22, 2024; 91 FR 7779, Feb. 18, 2026] § 1036.510 Supplemental Emission Test. (a) Measure emissions using the steady-state SET duty cycle as described in this section. Note that the SET duty cycle is operated as a ramped-modal cycle rather than discrete steady-state test points. (b) Procedures apply differently for testing certain kinds of engines and powertrains as follows: (1) For testing nonhybrid engines, the SET duty cycle is based on normalized speed and torque values relative to certain maximum values. Denormalize speed as described in 40 CFR 1065.512. Denormalize torque as described in 40 CFR 1065.610(d). Note that idle points are to be run at conditions simulating neutral or park on the transmission. (2) Test hybrid powertrains as described in § 1036.545, except as specified in this paragraph (b)(2). Do not compensate the duty cycle for the distance driven as described in § 1036.545(g)(4). For hybrid engines, select the transmission model parameters as described in § 1036.510(b)(2)(viii), . Disregard duty cycles in § 1036.545(j). For cycles that begin with idle, leave the transmission in neutral or park for the full initial idle segment. Place the transmission into drive no earlier than 5 seconds before the first nonzero vehicle speed setpoint. For SET testing only, place the transmission into park or neutral when the cycle reaches the final idle segment. Use the following vehicle parameters instead of those in § 1036.545 to define the vehicle model in § 1036.545(a)(3): (i) Determine the vehicle test mass, M, Where: P contrated Example: P contrated M 1.31 M (ii) Determine the vehicle frontal area, A front, (A) For M Example: M A front − − 8 2 − 4 A front 2 (B) For M A front 2 (iii) Determine the vehicle drag area, C d A Where: g 2 ρ ρ 3 Example: C d A 2 (iv) Determine the coefficient of rolling resistance, C rr, Example: C rr (v) Determine the vehicle curb mass, M curb Example: M curb 2 M curb (vi) Determine the linear equivalent mass of rotational moment of inertias, M rotating Example: M rotating M rotating (vii) Select a combination of drive axle ratio, k a r, 2 (viii) If you are certifying a hybrid engine, use a default transmission efficiency of 0.95 and create the vehicle model along with its default transmission shift strategy as described in § 1036.545(a)(3)(ii). Specify the transmission type as Automatic Transmission for all engines and for all duty cycles, except that the transmission type is Automated Manual Transmission for Heavy HDE operating over the SET duty cycle. For automatic transmissions set neutral idle to “Y” in the vehicle file. Select gear ratios for each gear as shown in the following table: Table 1 to Paragraph (b)(2)(viii) Gear No. Spark-ignition HDE, Heavy HDE—LLC and Heavy HDE— 1 3.10 3.51 12.8 2 1.81 1.91 9.25 3 1.41 1.43 6.76 4 1.00 1.00 4.90 5 0.71 0.74 3.58 6 0.61 0.64 2.61 7 1.89 8 1.38 9 1.00 10 0.73 Lockup Gear 3 3 (c) Measure emissions using the SET duty cycle shown in Table 1 of this section to determine whether engines meet the steady-state compression-ignition standards specified in subpart B of this part. Table 1 of this section specifies test settings, as follows: (1) The duty cycle for testing nonhybrid engines involves a schedule of normalized engine speed and torque values. Note that nonhybrid powertrains are generally tested as engines, so this section does not describe separate procedures for that configuration. (2) The duty cycle for testing hybrid powertrains involves a schedule of vehicle speeds and road grade as follows: (i) Determine road grade at each point based on the continuous rated power of the hybrid powertrain, P contrated v ref[speed] Example for SET mode 3a in Table 1 of this section: P contrated v refB Road grade − 9 3 − − 7 2 − 5 2 − 4 2 − 4 − − 2 − − 1 Road grade (ii) Use the vehicle C speed determined in § 1036.520. Determine vehicle A and B speeds as follows: (A) Determine vehicle A speed using the following equation: Example: v refC v refA (B) Determine vehicle B speed using the following equation: Example: v refB (3) Table 1 follows: (d) Determine criteria pollutant emissions for plug-in hybrid powertrains as follows: (1) Carry out a charge-sustaining test as described in paragraph (b)(2) of this section. (2) Carry out a charge-depleting test as described in paragraph (b)(2) of this section, except as follows: (i) Fully charge the RESS after preconditioning. (ii) Operate the engine or powertrain continuously over repeated SET duty cycles until you reach the end-of-test criterion defined in 40 CFR 1066.501(a)(3). (iii) Calculate emission results for each SET duty cycle. Figure 1 to paragraph (d)(4) of this section provides an example of a charge-depleting test sequence where there are two test intervals that contain engine operation. (3) Report the highest emission result for each criteria pollutant from all tests in paragraphs (d)(1) and (2) of this section, even if those individual results come from different test intervals. (4) The following figure illustrates an example of an SET charge-depleting test sequence: Figure 1 to Paragraph (d)(4) of § 1036.510—SET Charge-Depleting Criteria Pollutant Test Sequence. (e) Determine greenhouse gas pollutant emissions for plug-in hybrid powertrains using the emissions results for all the SET test intervals for both charge-depleting and charge-sustaining operation from paragraph (d)(2) of this section. Calculate the utility factor-weighted composite mass of emissions from the charge-depleting and charge-sustaining test results, e UF[emission]comp, Eq. 1036.510-10 Where: i N e [emission][int]CDi i, i UF DCDi D CDi i, i UF DCD0 j M e [emission][int]CS j j, j UF RCD R CD, R CD N Eq. 1036.510-11 Where: k Q v k, k v Δ t f record f record Example using the charge-depletion test in figure 1 to paragraph (d)(4) of this section for the SET for CO 2 emission determination: Q v 1 v 2 v 3 f record Δ t D CD1 D CD2 D CD3 D CD4 D CD5 N UF DCD1 UF DCD2 UF DCD3 UF DCD4 UF DCD5 e CO2SETCD1 e CO2SETCD2 e CO2SETCD3 e CO2SETCD4 e CO2SETCD5 M e CO2SETCS UF RCD (f) Calculate and evaluate cycle-validation criteria as specified in 40 CFR 1065.514 for nonhybrid engines and § 1036.545 for hybrid powertrains. (g) Calculate the total emission mass of each constituent, m, W, W P sys [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29743, Apr. 22, 2024; 91 FR 7779, Feb. 18, 2026] § 1036.512 Federal Test Procedure. (a) Measure emissions using the transient Federal Test Procedure (FTP) as described in this section to determine whether engines meet the emission standards in subpart B of this part. Operate the engine or hybrid powertrain over one of the following transient duty cycles: (1) For engines subject to spark-ignition standards, use the transient test interval described in paragraph (b) of appendix B to this part. (2) For engines subject to compression-ignition standards, use the transient test interval described in paragraph (c) of appendix B to this part. (b) Procedures apply differently for testing certain kinds of engines and powertrains as follows: (1) The transient test intervals for nonhybrid engine testing are based on normalized speed and torque values. Denormalize speed as described in 40 CFR 1065.512. Denormalize torque as described in 40 CFR 1065.610(d). (2) Test hybrid powertrains as described in § 1036.510(b)(2), with the following exceptions: (i) Replace P contrated P rated, (ii) Keep the transmission in drive for all idle segments after the initial idle segment. (iii) For hybrid engines, you may request to change the engine-commanded torque at idle to better represent curb idle transmission torque (CITT). (iv) For plug-in hybrid powertrains, test over the FTP in both charge-sustaining and charge-depleting operation for criteria pollutant determination. (c) Except as specified in paragraph (d) of this section for plug-in hybrid powertrains, the FTP duty cycle consists of an initial run through the test interval from a cold start as described in 40 CFR part 1065, subpart F, followed by a (20 ±1) minute hot soak with no engine operation, and then a final hot start run through the same transient test interval. Engine starting is part of both the cold-start and hot-start test intervals. Calculate the total emission mass of each constituent, m, W, W P sys P sys Eq. 1036.512-1 (d) Determine criteria pollutant emissions for plug-in hybrid powertrains as follows: (1) Carry out a charge-sustaining test as described in paragraph (b)(2) of this section. (2) Carry out a charge-depleting test as described in paragraph (b)(2) of this section, except as follows: (i) Fully charge the battery after preconditioning. (ii) Operate the engine or powertrain over one FTP duty cycle followed by alternating repeats of a 20-minute soak and a hot start test interval until you reach the end-of-test criteria defined in 40 CFR 1066.501(a)(3). (iii) Calculate emission results for each successive pair of test intervals. Calculate the emission result by treating the first of the two test intervals as a cold-start test. Figure 1 to paragraph (d)(4) of this section provides an example of a charge-depleting test sequence where there are three test intervals with engine operation for two overlapping FTP duty cycles. (3) Report the highest emission result for each criteria pollutant from all tests in paragraphs (d)(1) and (2) of this section, even if those individual results come from different test intervals. (4) The following figure illustrates an example of an FTP charge-depleting test sequence: Figure 1 to Paragraph (d)(4) of § 1036.512—FTP Charge-Depleting Criteria Pollutant Test Sequence (e) Determine CO 2 e UF[emission]comp 2 (f) Calculate and evaluate cycle-validation criteria as specified in 40 CFR 1065.514 for nonhybrid engines and § 1036.545 for hybrid powertrains. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29743, Apr. 22, 2024; 91 FR 7780, Feb. 18, 2026] § 1036.514 Low Load Cycle. Measure emissions using the transient Low Load Cycle (LLC) as described in this section to determine whether engines meet the LLC emission standards in § 1036.104. The LLC duty cycle is described in paragraph (d) of appendix B to this part. Procedures apply differently for testing certain kinds of engines and powertrains as follows: (a) Test nonhybrid engines using the following procedures: (1) Use the normalized speed and torque values for engine testing in the LLC duty cycle. Denormalize speed and torque values as described in 40 CFR 1065.512 and 1065.610 with the following additional requirements for testing at idle: (i) Apply the accessory load at idle in paragraph (c) of this section using declared idle power as described in 40 CFR 1065.510(f)(6). Declared idle torque must be zero. (ii) Apply CITT in addition to accessory load as described in this paragraph (a)(1)(ii). Set reference speed and torque values as described in 40 CFR 1065.610(d)(3)(vi) for all idle segments that are 200 s or shorter to represent the transmission operating in drive. For longer idle segments, set the reference speed and torque values to the warm-idle-in-drive values for the first three seconds and the last three seconds of the idle segment. For the points in between, set the reference speed and torque values to the warm-idle-in-neutral values to represent the transmission being manually shifted from drive to neutral shortly after the extended idle starts and back to drive shortly before it ends. (2) Calculate and evaluate cycle-validation criteria as described in 40 CFR 1065.514, except as specified in paragraph (e) of this section. (b) Test hybrid powertrains as described in § 1036.510(b)(2), with the following exceptions: (1) Replace P contrated P rated (2) Keep the transmission in drive for all idle segments 200 seconds or less. For idle segments more than 200 seconds, leave the transmission in drive for the first 3 seconds of the idle segment, then immediately place the transmission in park or neutral, and shift the transmission into drive again 3 seconds before the end of the idle segment. The end of the idle segment occurs at the first nonzero vehicle speed setpoint. (3) For hybrid engines, you may request to change the GEM-generated engine reference torque at idle to better represent curb idle transmission torque (CITT). (4) Adjust procedures in this section as described in § 1036.510(d) for plug-in hybrid powertrains, replacing “SET” with “LLC”. Note that the LLC is therefore the preconditioning duty cycle for plug-in hybrid powertrains. (5) Calculate and evaluate cycle-validation criteria as specified in § 1036.545. (c) Include vehicle accessory loading as follows: (1) Apply a vehicle accessory load for each idle point in the cycle using the power values in the following table: Table 1 to Paragraph ( c Primary intended service class Power representing accessory load Light HDE 1.5 Medium HDE 2.5 Heavy HDE 3.5 (2) For nonhybrid engine testing, apply vehicle accessory loads in addition to any applicable CITT. (3) Additional provisions related to vehicle accessory load apply for engines with stop-start technology and hybrid powertrains where the accessory load is applied to the engine shaft. Account for the loss of mechanical work due to the lack of any idle accessory load during engine-off conditions by determining the total loss of mechanical work from idle accessory load during all engine-off intervals over the entire test interval and distributing that work over the engine-on portion of the entire test interval based on a calculated average power. You may determine the engine-off time by running practice cycles or through engineering analysis. (d) Except as specified in paragraph (b)(4) of this section for plug-in hybrid powertrains, the test sequence consists of preconditioning the engine by running one or two FTPs with each FTP followed by (20 ± 1) minutes with no engine operation and a hot start run through the LLC. You may start any preconditioning FTP with a hot engine. Perform testing as described in 40 CFR 1065.530 for a test interval that includes engine starting. Calculate the total emission mass of each constituent, m, W, P sys P sys (e) For testing spark-ignition gaseous-fueled engines with fuel delivery at a single point in the intake manifold, you may apply the alternative cycle-validation criteria for the LLC in the following table: Table 2 to Paragraph ( e a Parameter Speed Torque Power Slope, a 1 0.800 ≤ a 1 0.800 ≤ a 1 Absolute value of intercept, | a 0 Standard error of the estimate, SEE ≤15% of maximum mapped power. Coefficient of determination, r 2 ≥0.650 ≥0.650. a [89 FR 29746, Apr. 22, 2024, as amended at 91 FR 7780, Feb. 18, 2026] § 1036.520 Determining power and vehicle speed values for powertrain testing. This section describes how to determine the system peak power and continuous rated power of hybrid and nonhybrid powertrain systems and the vehicle speed for carrying out duty-cycle testing under this part and § 1036.545. (a) You must map or re-map an engine before a test if any of the following apply: (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) Set up the powertrain test according to § 1036.545, with the following exceptions: (1) Use vehicle parameters, other than power, as specified in § 1036.510(b)(2). Use the applicable automatic transmission as specified in § 1036.510(b)(2)(viii). (2) Select a manufacturer-declared value for P contrated (c) Verify the following before the start of each test interval: (1) The state-of-charge of the rechargeable energy storage system (RESS) must be at or above 90% of the operating range between the minimum and maximum RESS energy levels specified by the manufacturer. (2) The conditions of all hybrid system components must be within their normal operating range as declared by the manufacturer, including ensuring that no features are actively limiting power or vehicle speed. (d) Carry out the test as described in this paragraph (d). Warm up the powertrain by operating it. We recommend operating the powertrain at any vehicle speed and road grade that achieves 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. Within 90 seconds after concluding the warm-up, operate the powertrain over a continuous trace meeting the following specifications: (1) Bring the vehicle speed to 0 mi/hr and let the powertrain idle at 0 mi/hr for 50 seconds. (2) Set maximum driver demand for a full load acceleration at 6.0% road grade with an initial vehicle speed of 0 mi/hr, continuing for 268 seconds. You may increase initial vehicle speed up to 5 mi/hr to minimize clutch slip. (3) Linearly ramp the grade from 6.0% down to 0.0% over 300 seconds. Stop the test after the acceleration is less than 0.02 m/s 2 (e) Record the powertrain system angular speed and torque values measured at the dynamometer at 100 Hz and use these in conjunction with the vehicle model to calculate vehicle system power, P sys,vehicle. P sys, (f) Calculate the system power, P sys, (1) For testing with the speed and torque measurements at the transmission input shaft, P sys P sys,vehicle, (2) For testing with the speed and torque measurements at the axle input shaft or the wheel hubs, determine P sys Where: P sys,vehicle ε trans ε axle Example: P sys,vehicle P sys (g) For each 200-ms (5-Hz) time step, t, (1) Calculate the standard deviation, σ t Where: N P sysi sys P sys (t) (2) Calculate the 5-Hz values for COV t t, (h) Determine rated power, P rated, (i) Determine continuous rated power, P contrated (1) For nonhybrid powertrains, P contrated P rated (2) For hybrid powertrains, P contrated (j) Determine vehicle C speed, v refC (1) If the maximum P sys t P contrated v refC P sys t P contrated P sys t P contrated v refC. (2) Otherwise, v refC (3) You may use a declared v refC v refC v refC (4) Manufacturers may request approval to use an alternative vehicle C speed in place of the measured vehicle C speed determined in this paragraph (j) for series hybrid applications. Approval will be contingent upon justification that the measured vehicle C speed is not representative of the expected real-world cruise speed. (k) If P contrated P contrated P contrated [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29747, Apr. 22, 2024; 91 FR 7780, Feb. 18, 2026] § 1036.525 Clean Idle test. Measure emissions using the procedures described in this section to determine whether engines and hybrid powertrains meet the clean idle emission standards in § 1036.104(b). For plug-in hybrid powertrains, perform the test with the hybrid function disabled. (a) The clean idle test consists of two separate test intervals as follows: (1) Mode 1 consists of engine operation with a speed setpoint at your recommended warm idle speed. Set the dynamometer torque demand corresponding to vehicle power requirements at your recommended warm idle speed that represent in-use operation. (2) Mode 2 consists of engine operation with a speed setpoint at 1100 r/min. Set the dynamometer torque demand to account for the sum of the following power loads: (i) Determine power requirements for idling at 1100 r/min. (ii) Apply a power demand of 2 kW to account for appliances and accessories the vehicle operator may use during rest periods. (3) Determine torque demand for testing under this paragraph (a) based on an accessory load that includes the engine cooling fan, alternator, coolant pump, air compressor, engine oil and fuel pumps, and any other engine accessory that operates at the specific test condition. Also include the accessory load from the air conditioning compressor operating at full capacity for Mode 2. Do not include any other load for air conditioning or other cab or vehicle accessories except as specified. (b) Perform the Clean Idle test as follows: (1) Warm up the engine by operating it over the FTP or SET duty cycle, or by operating it at any speed above peak-torque speed and at (65 to 85) % of maximum mapped power. The warm-up is complete when the engine thermostat controls engine temperature or when the engine coolant's temperature is within 2% of its mean value for at least 2 minutes. (2) Start operating the engine in Mode 1 as soon as practical after the engine warm-up is complete. (3) Start sampling emissions 10 minutes after reaching the speed and torque setpoints and continue emission sampling and engine operation at those setpoints. Stop emission sampling after 1200 seconds to complete the test interval. (4) Linearly ramp the speed and torque setpoints over 5 seconds to start operating the engine in Mode 2. Sample emissions during Mode 2 as described in paragraph (b)(3) of this section. (c) Verify that the test speed stays within ±50 r/min of the speed setpoint throughout the test. The torque tolerance is ±2 percent of the maximum mapped torque at the test speed. Verify that measured torque meets the torque tolerance relative to the torque setpoint throughout the test. (d) Calculate the mean mass emission rate of NO X m m NOx [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29748, Apr. 22, 2024] § 1036.530 Test procedures for off-cycle testing. (a) General. (b) Vehicle preparation and measurement procedures. (2) Begin emission sampling and data collection as described in 40 CFR 1065.935(c)(3) before starting the engine at the beginning of the shift-day. Start the engine only after confirming that engine coolant temperature is at or below 40 °C. (3) Measure emissions over one or more shift-days as specified in subpart E of this part. (4) For engines subject to compression-ignition standards, record 1 Hz measurements of ambient temperature near the vehicle. (c) Test Intervals. (1) Spark-ignition. (2) Compression-ignition. (i) Begin and end each test interval with a pair of consecutive data points with no exclusions as described in paragraph (c)(3) of this section. Select the last data point of each test interval such that the test interval includes 300 seconds of data with no exclusions, as described in paragraph (d) of this section. The test interval may be a fraction of a second more or less than 300 seconds to account for the precision of the time stamp in recording 1 Hz data. A test interval may include up to 599 seconds of data with continuous exclusions; invalidate any test interval that includes at least 600 seconds of continuous sampling with excluded data. (ii) The first 300 second test interval starts with the first pair of consecutive data points with no exclusions. Determine the start of each subsequent 300 second test interval by finding the first pair of consecutive data points with no exclusions after the initial data point of the previous test interval. (iii) The last 300 second test interval ends with the last pair of consecutive data points with no exclusions before the end of the shift day. (3) Excluded data. (i) An analyzer or flow meter is performing zero and span drift checks or zero and span calibrations, including any time needed for the analyzer to stabilize afterward, consistent with good engineering judgment. (ii) The engine is off, except as specified in § 1036.415(g). (iii) The engine is performing an infrequent regeneration. Do not exclude data related to any other AECDs, except as specified in paragraph (c)(3)(vi) of this section. (iv) The recorded ambient air temperature is below 5 °C or above the temperature calculated using the following equation. Where: h Example: h T max T max (v) The vehicle is operating at an elevation more than 5,500 feet above sea level. (vi) An engine has one or more active AECDs for emergency vehicles under § 1036.115(h)(4). (vii) A single data point does not meet any of the conditions specified in paragraphs (c)(3)(i) through (vi) of this section, but it is preceded and followed by data points that both meet one or more of the specified exclusion conditions. (d) Assembling test intervals. (1) Treat these test subintervals as continuous for calculating duration of the test interval for engines subject to compression-ignition standards. (2) Calculate emission mass during each test subinterval and sum those subinterval emission masses to determine the emission mass over the test interval. Calculate emisson mass as described in 40 CFR 1065.650(c)(2)(i), with the following exceptions and clarifications: (i) Correct NO X (ii) Disregard the provision in 40 CFR 1065.650(g) for setting negative emission mass to zero for test intervals and subintervals. (iii) Calculation of emission mass in 40 CFR 1065.650 assumes a constant time interval, Δ t. t t (e) Normalized CO 2 emission mass over a 300 second test interval. 2 m CO2,norm,testinterval Where: m CO2,testinterval 2 e CO2FTPFCL 2 2 P max t testinterval Example: m CO2,testinterval e CO2FTPFCL P max t testinterval m CO2,norm,testinterval (f) Binning 300 second test intervals. 2 m CO2,norm,testinterval, Table 1 to Paragraph ( f Bin Normalized CO 2 Bin 1 m CO2,norm,testinterval Bin 2 m CO2,norm,testinterval (g) Off-cycle emissions quantities. (1) Spark-ignition. e [emission],offcycle, 2 Eq. 1036.530-3 Where: m [emission] m CO2 2 e CO2FTPFCL 2 Example: (2) Compression-ignition. (i) Off-cycle emissions quantity for bin 1. m NOx,offcycle,bin1 X Where: i N m NO X testinterval, i X i t testinterval, i i Example: N m NO X testinterval,1 m NO X testinterval,2 m NO X testinterval,3 t testinterval,1 t testinterval,2 t testinterval,3 m NOoffcycle,bin1, (ii) Off-cycle emissions quantity for bin 2. e [emission],offcycle,bin2, 2 Eq. 1036.530-5 Where: i N m [emission],testinterval,i i m CO2,testinterval,i 2 i e CO2,FTP,FCL 2 Example: N m NOx1 m NOx2 m NOx3 m CO2,1 m CO2,2 m CO2,3 e CO2,FTP,FCL (h) Shift-day ambient temperature. T amb (i) Graphical illustration. m (t) m (t) Figure 1 to Paragraph (i) of § 1036.530—Illustration of Integration of Mass of Emissions Over a Test Interval With Exclude Data Points (j) Fuel other than carbon-containing. (1) Use the following equation to determine the normalized equivalent CO 2 Eq. 1036.530-6 Where: W testinterval P max t testinterval Example: W testinterval P max t testinterval (2) Determine off-cycle emissions quantities as follows: (i) For engines subject to spark-ignition standards, use the following equation to determine the off-cycle emission quantity instead of Eq. 1036.530-3: Eq. 1036.530-7 Where: m [emission] W testinterval Example: (ii) For engines subject to compression-ignition standards, use Eq. 1036.530-4 to determine the off-cycle emission quantity for bin 1. (iii) For engines subject to compression-ignition standards, use the following equation to determine the off-cycle emission quantity for bin 2 instead of Eq. 1036.530-5: Eq. 1036.530-8 Where: i N m [emission],testinterval, i i W testinterval, i i Example: N m NOx1 m NOx2 m NOx3 W testinterval1 W testinterval2 W testinterval3 [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29748, Apr. 22, 2024] § 1036.535 Determining steady-state engine fuel maps and fuel consumption at idle. The procedures in this section describe how to determine an engine's steady-state fuel map and fuel consumption at idle for model year 2021 and later vehicles; these procedures apply as described in § 1036.505. Vehicle manufacturers may need these values to demonstrate compliance with standards under 49 CFR part 535. (a) General test provisions. (1) Map the engine's torque curve and declare engine idle speed as described in § 1036.505(c)(1) and (3). Perform emission measurements as described in 40 CFR 1065.501 and 1065.530 for discrete-mode steady-state testing. This section uses engine parameters and variables that are consistent with 40 CFR part 1065. (2) Measure NO X X (3) You may use shared data across engine configurations to the extent that the fuel-consumption rates remain valid. (4) The provisions related to carbon balance error verification in § 1036.543 apply for all testing in this section. These procedures are optional, but we will perform carbon balance error verification for all testing under this section. (5) Correct fuel mass flow rate to a mass-specific net energy content of a reference fuel as described in paragraph (e) of this section. (b) Steady-state fuel mapping. (1) Generate the fuel-mapping sequence of engine speed and torque setpoints as follows: (i) Select the following required speed setpoints: warm idle speed, f nidle n hi, f nidle n hi. f nidle f nidlemin. (ii) Select the following required torque setpoints at each of the selected speed setpoints: zero ( T T max mapped, T T max mapped. (A) Calculate 5 percent of T max mapped. T max. (B) Select T max T max (iii) You may select any additional speed and torque setpoints consistent with good engineering judgment. For example, you may need to select additional points if the engine's fuel consumption is nonlinear across the torque map. Avoid creating a problem with interpolation between narrowly spaced speed and torque setpoints near T max. T max T max,mapped. (iv) Start fuel-map testing at the highest speed setpoint and highest torque setpoint, followed by decreasing torque setpoints at the highest speed setpoint. Continue testing at the next lowest speed setpoint and the highest torque setpoint at that speed setpoint, followed by decreasing torque setpoints at that speed setpoint. Follow this pattern through all the speed and torque points, ending with the lowest speed ( f nidle f nidlemin T Figure 1 to Paragraph (b)(1)(iv) of § 1036.535—Illustration of Steady-State Fuel-Mapping Test Points and Run Order (v) The highest torque setpoint for each speed setpoint is an optional reentry point to restart fuel mapping after an incomplete test run. (vi) The lowest torque setpoint at each speed setpoint is an optional exit point to interrupt testing. Paragraph (b)(7) of this section describes how to interrupt testing at other times. (2) If the engine's warm idle speed is adjustable, set it to its minimum value, f nidlemin. (3) The measurement at each unique combination of speed and torque setpoints constitutes a test interval. Unless we specify otherwise, you may program the dynamometer to control either speed or torque for a given test interval, with operator demand controlling the other parameter. Control speed and torque so that all recorded speed points are within ±1% of n hi T max mapped (i) For steady-state engine operating points that cannot be achieved, and the operator demand stabilizes at minimum; program the dynamometer to control torque and let the engine govern speed (see 40 CFR 1065.512(b)(1)). Control torque so that all recorded engine torque points are within ±25 N·m from the target torque. The specified speed tolerance does not apply for the test interval. (ii) For steady-state engine operating points that cannot be achieved and the operator demand stabilizes at maximum and the speed setpoint is below 90% of n hi (iii) For steady-state engine operating points that cannot be achieved and the operator demand stabilizes at maximum and the speed setpoint is at or above 90% of n hi (iv) For the steady-state engine operating points at the minimum speed setpoint and maximum torque setpoint, you may program the dynamometer to control speed and let the engine govern torque. The specified torque tolerance does not apply for this test interval if operator demand stabilizes at its maximum or minimum limit. (4) Record measurements using direct and/or indirect measurement of fuel flow as follows: (i) Direct fuel-flow measurement. (ii) Indirect fuel-flow measurement. (A) For batch sampling, you may sample periodically into the bag over the course of multiple test intervals and read them as allowed in paragraph (b)(7)(i) of this section. You must determine a single background reading for all affected test intervals if you use the method described in this paragraph (b)(4)(ii)(A). (B) You may measure background concentration by sampling from the dilution air during the interruptions allowed in paragraph (b)(7)(i) of this section or at other times before or after test intervals. Measure background concentration within 30 minutes before the first test interval and within 30 minutes before each reentry point. Measure the corresponding background concentration within 30 minutes after each exit point and within 30 minutes after the final test interval. You may measure background concentration more frequently. Correct measured emissions for test intervals between a pair of background readings based on the average of those two values. Once the system stabilizes, collect a background sample over an averaging period of at least 30 seconds. (5) Warm up the engine as described in 40 CFR 1065.510(b)(2). Within 60 seconds after concluding the warm-up, linearly ramp the speed and torque setpoints over 5 seconds to the starting test point from paragraph (b)(1) of this section. (6) Stabilize the engine by operating at the specified speed and torque setpoints for (70 ± 1) seconds and then start the test interval. Record measurements during the test interval. Measure and report NO X (7) After completing a test interval, linearly ramp the speed and torque setpoints over 5 seconds to the next test point. (i) You may interrupt the fuel-mapping sequence before a reentry point as noted in paragraphs (b)(1)(v) and (vi) of this section. If you zero and span analyzers, read and evacuate background bag samples, or sample dilution air for a background reading during the interruption, the maximum time to stabilize in paragraph (b)(6) of this section does not apply. If you shut off the engine, restart with engine warm-up as described in paragraph (b)(5) of this section. (ii) You may interrupt the fuel-mapping sequence at a given speed setpoint before completing measurements at that speed. If this happens, you may measure background concentration and take other action as needed to validate test intervals you completed before the most recent reentry point. Void all test intervals after the last reentry point. Restart testing at the appropriate reentry point in the same way that you would start a new test. Operate the engine long enough to stabilize aftertreatment thermal conditions, even if it takes more than 70 seconds. In the case of an infrequent regeneration event, interrupt the fuel-mapping sequence and allow the regeneration event to finish with the engine operating at a speed and load that allows effective regeneration. (iii) If you void any one test interval, all the testing at that speed setpoint is also void. Restart testing by repeating the fuel-mapping sequence as described in this paragraph (b); include all voided speed setpoints and omit testing at speed setpoints that already have a full set of valid results. (8) If you determine fuel-consumption rates using emission measurements from the raw or diluted exhaust, calculate the mean fuel mass flow rate, m fuel Where: m fuel M C W Cmeas w C n x Ccombdry x H2Oexhdry 2 m CO2DEF 2 m CO2DEF M CO2 Example: (9) If you determine fuel-consumption rates using emission measurements with engines that utilize diesel exhaust fluid for NO X 2 Where: m DEF M CO2 w CH4N2O M CH4N2O Example: m DEF M CO2 w CH4N2O M CH4N2O m CO2DEF (10) Correct the measured or calculated mean fuel mass flow rate, at each of the operating points to account for mass-specific net energy content as described in paragraph (e) of this section. (c) Fuel consumption at idle. (1) The idle test sequence consists of measuring fuel consumption at four test points representing each combination of the following speed and torque setpoints in any order. (i) Speed setpoints for engines with adjustable warm idle speed are minimum warm idle speed, f nidlemin f nidlemax f nidle f nidle (ii) Torque setpoints are 0 and 100 N·m. (2) Control speed and torque as follows: (i) Adjustable warm idle speed. (ii) Nonadjustable warm idle speed. n hi T max mapped (3) Record measurements using direct and/or indirect measurement of fuel flow as follows: (i) Direct fuel flow measurement. (ii) Indirect fuel flow measurement. (4) Warm up the engine as described in 40 CFR 1065.510(b)(2). Within 60 seconds after concluding the warm-up, linearly ramp the speed and torque over 20 seconds to the first speed and torque setpoint. (5) The measurement at each unique combination of speed and torque setpoints constitutes a test interval. Operate the engine at the selected speed and torque set points for (180 ±1) seconds, and then start the test interval. Record measurements during the test interval. Measure and report NO X (6) After completing each test interval, repeat the steps in paragraphs (c)(4) and (5) of this section for all the remaining engine-idle test points. (7) Each test point represents a stand-alone measurement. You may therefore take any appropriate steps between test intervals to process collected data and to prepare engines and equipment for further testing. Note that the allowances for combining background in paragraph (b)(4)(ii)(B) of this section do not apply. If an infrequent regeneration event occurs, allow the regeneration event to finish; void the test interval if the regeneration starts during a measurement. (8) Correct the measured or calculated mean fuel mass flow rate, at each of the engine-idle operating points to account for mass-specific net energy content as described in paragraph (e) of this section. (d) Steady-state fuel maps used for cycle-average fuel mapping of the highway cruise cycles. (1) Select speed setpoints to cover a range of values to represent in-use operation at idle. Speed setpoints for engines with adjustable warm idle speed must include at least minimum warm idle speed, f nidlemin f nidlemax f nidle f nidle (2) Select the following torque setpoints at each speed setpoint to cover a range of values to represent in-use operation at idle: (i) The minimum torque setpoint is zero. (ii) Choose a maximum torque setpoint that is at least as large as the value determined by the following equation: Where: T fnstall f nstall f nidle f nidlemax f nidle f nstall f ntest P acc Example: T fnstall f ntest f nstall f nidle P acc T idlemaxest (iii) Select one or more equally spaced intermediate torque setpoints, as needed, such that the increment between torque setpoints is no greater than one-ninth of T max,mapped (e) Correction for net energy content. m fuel Eq. 1036.535-4 Where: E mfuelmeas w Cref E mfuelCref. E mfuelCref W Cref Example: = 0.933 g/s (f) [Reserved] (g) Measured vs. declared fuel consumption. (1) Select fuel consumption rates in g/s to characterize the engine's fuel maps. You must select a declared value for each test point that is at or above the corresponding value determined in paragraphs (b) through (d) of this section, including those from redundant measurements. (2) Declared fuel consumption serves as emission standards under § 1036.108. These are the values that vehicle manufacturers will use for certification under 40 CFR part 1037. Note that production engines are subject to GEM cycle-weighted limits as described in § 1036.301. (3) If you perform the carbon balance error verification, select declared values that are at or above the following emission measurements: (i) If you pass the ε rC (ii) If you fail ε rC ε aC ε aCrate (iii) If you fail all three verifications, you must either void the test interval or use the highest value from direct and indirect fuel measurements. Note that we will consider our test results to be invalid if we fail all three verifications. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29750, Apr. 22, 2024; 89 FR 51235, June 17, 2024; 91 FR 7780, Feb. 18, 2026] § 1036.540 Determining cycle-average engine fuel maps. (a) Overview. (1) Determine the engine's torque maps as described in § 1036.505(c). (2) Determine the engine's steady-state fuel map and fuel consumption at idle as described in § 1036.535. If you are applying cycle-average fuel mapping for highway cruise cycles, you may instead use GEM's default fuel map instead of generating the steady-state fuel map in § 1036.535(b). (3) Simulate several different vehicle configurations using GEM (see 40 CFR 1037.520) to create new engine duty cycles as described in paragraph (c) of this section. The transient vehicle duty cycles for this simulation are in 40 CFR part 1037, appendix A; the highway cruise cycles with grade are in 40 CFR part 1037, appendix D. Note that GEM simulation relies on vehicle service classes as described in 40 CFR 1037.140. (4) Test the engines using the new duty cycles to determine fuel consumption, cycle work, and average vehicle speed as described in paragraph (d) of this section and establish GEM inputs for those parameters for further vehicle simulations as described in paragraph (e) of this section. (b) General test provisions. (1) [Reserved] (2) The provisions related to carbon balance error verification in § 1036.543 apply for all testing in this section. These procedures are optional, but we will perform carbon balance error verification for all testing under this section. (3) Correct fuel mass to a mass-specific net energy content of a reference fuel as described in paragraph (d)(13) of this section. (4) This section uses engine parameters and variables that are consistent with 40 CFR part 1065. (c) Create engine duty cycles. (1) Set up GEM to simulate your engine's operation based on your engine's torque maps, steady-state fuel maps, warm-idle speed as defined in 40 CFR 1037.520(h)(1), and fuel consumption at idle as described in paragraphs (a)(1) and (2) of this section. (2) Set up GEM with transmission parameters for different vehicle service classes and vehicle duty cycles. Specify the transmission's torque limit for each gear as the engine's maximum torque as determined in 40 CFR 1065.510. Specify the transmission type as Automatic Transmission for all engines and for all engine and vehicle duty cycles, except that the transmission type is Automated Manual Transmission for Heavy HDE operating over the highway cruise cycles or the SET duty cycle. For automatic transmissions set neutral idle to “Y” in the vehicle file. Select gear ratios for each gear as shown in the following table: Table 1 to Paragraph ( c Gear No. Spark-ignition HDE, light HDE, and medium HDE— Heavy HDE— Heavy HDE— 1 3.10 3.51 12.8 2 1.81 1.91 9.25 3 1.41 1.43 6.76 4 1.00 1.00 4.90 5 0.71 0.74 3.58 6 0.61 0.64 2.61 7 — — 1.89 8 — — 1.38 9 — — 1.00 10 — — 0.73 Lockup Gear 3 3 — (3) Run GEM for each simulated vehicle configuration and use the GEM outputs of instantaneous engine speed and engine flywheel torque for each vehicle configuration to generate a 10 Hz transient duty cycle corresponding to each vehicle configuration operating over each vehicle duty cycle. Run GEM for the specified number of vehicle configurations. You may run additional vehicle configurations to represent a wider range of in-use vehicles. Run GEM as follows: (i) Determining axle ratio and tire size. k a, for each vehicle configuration based on the corresponding designated engine speed ( f nrefA f nrefB f nrefC f nrefD f ntest and k a Where: f n[speed] k topgear v ref Example for a vocational Light HDV or vocational Medium HDV with a 6-speed automatic transmission at B speed (Test 3 or 4 in Table 3 of this section): f nrefB k aB k topgear v ref (ii) Vehicle configurations for Spark-ignition HDE, Light HDE, and Medium HDE. (iii) Vehicle configurations for Heavy HDE. (iv) Vehicle configurations for mixed-use engines. (v) Defining GEM inputs. (d) Test the engine with GEM cycles. (1) Operate the engine over a sequence of required and optional engine duty cycles as follows: (i) Sort the list of engine duty cycles into three separate groups by vehicle duty cycle: transient vehicle cycle, 55 mi/hr highway cruise cycle, and 65 mi/hr highway cruise cycle. (ii) Within each group of engine duty cycles derived from the same vehicle duty cycle, first run the engine duty cycle with the highest reference cycle work, followed by the cycle with the lowest cycle work; followed by the cycle with second-highest cycle work, followed by the cycle with the second-lowest cycle work; continuing through all the cycles for that vehicle duty cycle. The series of engine duty cycles to represent a single vehicle duty cycle is a single fuel-mapping sequence. Each engine duty cycle represents a different interval. Repeat the fuel-mapping sequence for the engine duty cycles derived from the other vehicle duty cycles until testing is complete. (iii) Operate the engine over two full engine duty cycles to precondition before each interval in the fuel-mapping sequence. Precondition the engine before the first and second engine duty cycle in each fuel-mapping sequence by repeating operation with the engine duty cycle with the highest reference cycle work over the relevant vehicle duty cycle. The preconditioning for the remaining cycles in the fuel-mapping sequence consists of operation over the preceding two engine duty cycles in the fuel-mapping sequence (with or without measurement). For transient vehicle duty cycles, start each engine duty cycle within 10 seconds after finishing the preceding engine duty cycle (with or without measurement). For highway cruise cycles, start each engine duty cycle and interval after linearly ramping to the speed and torque setpoints over 5 seconds and stabilizing for 15 seconds. (2) If the engine has an adjustable warm idle speed setpoint, set it to the value defined in 40 CFR 1037.520(h)(1). (3) Control speed and torque to meet the cycle validation criteria in 40 CFR 1065.514 for each interval, except that the standard error of the estimate in 40 CFR 1065.514(f)(3) is the only speed criterion that applies if the range of reference speeds is less than 10 percent of the mean reference speed. For spark-ignition gaseous-fueled engines with fuel delivery at a single point in the intake manifold, you may apply the alternative cycle-validation criteria in table 5 to this paragraph (c)(3) for transient testing. Note that 40 CFR part 1065 does not allow reducing cycle precision to a lower frequency than the 10 Hz reference cycle generated by GEM. Table 5 to Paragraph ( c a Parameter Speed Torque Power Slope, a 1 Absolute value of intercept, | a 0 ≤3% of maximum mapped torque Standard error of the estimate, SEE ≤15% of maximum mapped torque ≤15% of maximum mapped power. Coefficient of determination, r 2 ≥0.700 ≥0.750. a (4) Record measurements using direct and/or indirect measurement of fuel flow as follows: (i) Direct fuel-flow measurement. (ii) Indirect fuel-flow measurement. (A) If you use batch sampling to measure background emissions, you may sample periodically into the bag over the course of multiple intervals. If you use this provision, you must apply the same background readings to correct emissions from each of the applicable intervals. (B) You may determine background emissions by sampling from the dilution air over multiple engine duty cycles. If you use this provision, you must allow sufficient time for stabilization of the background measurement; followed by an averaging period of at least 30 seconds. Use the average of the two background readings to correct the measurement from each engine duty cycle. The first background reading must be taken no greater than 30 minutes before the start of the first applicable engine duty cycle and the second background reading must be taken no later than 30 minutes after the end of the last applicable engine duty cycle. Background readings may not span more than a full fuel-mapping sequence for a vehicle duty cycle. (5) Warm up the engine as described in 40 CFR 1065.510(b)(2). Within 60 seconds after concluding the warm-up, start the linear ramp of speed and torque over 20 seconds to the first speed and torque setpoint of the preconditioning cycle. (6) Precondition the engine before the start of testing as described in paragraph (d)(1)(iii) of this section. (7) Operate the engine over the first engine duty cycle. Record measurements during the interval. Measure and report NO X (8) Continue testing engine duty cycles that are derived from the other vehicle duty cycles until testing is complete. (9) You may interrupt the fuel-mapping sequence after completing any interval. You may calibrate analyzers, read and evacuate background bag samples, or sample dilution air for measuring background concentration before restarting. Shut down the engine during any interruption. If you restart the sequence within 30 minutes or less, restart the sequence at paragraph (d)(6) of this section and then restart testing at the next interval in the fuel-mapping sequence. If you restart the sequence after more than 30 minutes, restart the sequence at paragraph (d)(5) of this section and then restart testing at the next interval in the fuel-mapping sequence. (10) The following provisions apply for infrequent regeneration events, other interruptions during intervals, and otherwise voided intervals: (i) Stop testing if an infrequent regeneration event occurs during an interval or an interval is interrupted for any other reason. Void the interrupted interval and any additional intervals for which you are not able to meet requirements for measuring background concentration. If the infrequent regeneration event occurs between intervals, void completed intervals only if you are not able to meet requirements for measuring background concentration for those intervals. (ii) If an infrequent regeneration event occurs, allow the regeneration event to finish with the engine operating at a speed and load that allows effective regeneration. (iii) If you interrupt testing during an interval, if you restart the sequence within 30 minutes or less, restart the sequence at paragraph (d)(6) of this section and then restart testing at the next interval in the fuel-mapping sequence. If you restart the sequence after more than 30 minutes, restart the sequence at paragraph (d)(5) of this section and then restart testing at the next interval in the fuel-mapping sequence. (iv) If you void one or more intervals, you must perform additional testing to get results for all intervals. You may rerun a complete fuel-mapping sequence or any contiguous part of the fuel-mapping sequence. If you get a second valid measurement for any interval, use only the result from the last valid interval. If you restart the sequence within 30 minutes or less, restart the sequence at paragraph (d)(6) of this section and then restart testing at the first selected interval in the fuel-mapping sequence. If you restart the sequence after more than 30 minutes, restart the sequence at paragraph (d)(5) of this section and then restart testing at the first selected interval in the fuel-mapping sequence. Continue testing until you have valid results for all intervals. The following examples illustrate possible scenarios for a partial run through a fuel-mapping sequence: (A) If you voided only the interval associated with the fourth engine duty cycle in the sequence, you may restart the sequence using the second and third engine duty cycles as the preconditioning cycles and stop after completing the interval associated with the fourth engine duty cycle. (B) If you voided the intervals associated with the fourth and sixth engine duty cycles, you may restart the sequence using the second and third engine duty cycles for preconditioning and stop after completing the interval associated with the sixth engine duty cycle. (11) You may send signals to the engine controller during the test, such as current transmission gear and vehicle speed, if that allows engine operation to better represent in-use operation. (12) Calculate the fuel mass, m fuel (i) Determine fuel-consumption using emission measurements from the raw or diluted exhaust. Calculate the mass of fuel for each duty cycle, m fuel[cycle] (A) For calculations that use continuous measurement of emissions and continuous CO 2 m fuel[cycle] Eq. 1036.540-3 Where: M C w Cmeas α, β, w C. α, β, γ, δ i N n 1 x Ccombdry i x H2Oexhdry i 2 Δ t f record M CO2 m CO2DEF i 2 m CO2DEF i Example: M C w Cmeas N n 1 n 2 x Ccombdryi −3 x Ccombdryi −3 x H2Oexh1 −2 x H2Oexh2 −2 f record Δ t M CO2 m CO2DEF1 m CO2DEF2 (B) If you measure batch emissions and continuous CO 2 m fuel[cycle] (C) If you measure continuous emissions and batch CO 2 m fuel[cycle] (D) If you measure batch emissions and batch CO 2 m fuel[cycle] (ii) Manufacturers may choose to measure fuel mass flow rate. Calculate the mass of fuel for each duty cycle, m fuel[cycle], Where: i N N m fuel i i i Δ t ƒ record ƒ record Example: N m fuel1 m fuel2 ƒ record Δ t m fueltransient m fuel6680 m fueltransient (13) Correct the measured or calculated fuel mass, m fuel, m fuel m fuel (e) Determine GEM inputs. (1) Using the calculated fuel mass consumption values, m fuel[cycle] (2) We will determine m fuel[cycle] (3) For the transient cycle, calculate engine output speed per unit vehicle speed, by taking the average engine speed measured during the engine test while the vehicle is moving and dividing it by the average vehicle speed provided by GEM. Note that the engine cycle created by GEM has a flag to indicate when the vehicle is moving. (4) Determine engine idle speed and torque, by taking the average engine speed and torque measured during the engine test while the vehicle is not moving. Note that the engine cycle created by GEM has a flag to indicate when the vehicle is moving. (5) For the cruise cycles, calculate the average engine output speed, f nengine T engine (6) Determine positive work according to 40 CFR part 1065, W [cycle], (7) The following tables illustrate the GEM data inputs corresponding to the different vehicle configurations for a given duty cycle: (i) For the transient cycle: (ii) For the cruise cycles: Table 7 to Paragraph ( e ii Parameter Configuration 1 2 3 4 . . . n m fuel [ cycle ] f nengine [ cycle ] T engine[cycle] W [ cycle ] [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29751, Apr. 22, 2024; 91 FR 7780, Feb. 18, 2026] § 1036.543 Carbon balance error verification. The optional carbon balance error verification in 40 CFR 1065.543 compares independent assessments of the flow of carbon through the system (engine plus aftertreatment). This procedure applies for each individual interval in §§ 1036.535(b), (c), and (d), 1036.540, and 1036.545. [89 FR 29752, Apr. 22, 2024] § 1036.545 Powertrain testing. This section describes the procedure to measure fuel consumption and create engine fuel maps by testing a powertrain that includes an engine coupled with a transmission, drive axle, and hybrid components or any assembly with one or more of those hardware elements. Engine fuel maps are part of demonstrating compliance with standards under 49 CFR part 535; the powertrain test procedure in this section is one option for generating this fuel-mapping information as described in § 1036.505. Additionally, this powertrain test procedure is one option for certifying hybrid powertrains to the engine standards in § 1036.104. (a) General test provisions. (1) [Reserved] (2) The procedures of 40 CFR part 1065 apply for testing in this section except as specified. This section uses engine parameters and variables that are consistent with 40 CFR part 1065. (3) Powertrain testing depends on models to calculate certain parameters. You can use the detailed equations in this section to create your own models, or use the GEM HIL model contained within GEM Phase 2, Version 4.0 (incorporated by reference, see § 1036.810) to simulate vehicle hardware elements as follows: (i) Create driveline and vehicle models that calculate the angular speed setpoint for the test cell dynamometer, f nref,dyno, (ii) Create a driver model or use the GEM HIL model's driver submodel to simulate a human driver modulating the throttle and brake pedals to follow the test cycle as closely as possible. (iii) Create a cycle-interpolation model or use the GEM HIL model's cycle submodel to interpolate the duty-cycles and feed the driver model the duty-cycle reference vehicle speed for each point in the duty-cycle. (4) The powertrain test procedure in this section is designed to simulate operation of different vehicle configurations over specific duty cycles. See paragraphs (h) and (j) of this section. (5) For each test run, record engine speed and torque as defined in 40 CFR 1065.915(d)(5) with a minimum sampling frequency of 1 Hz. These engine speed and torque values represent a duty cycle that can be used for separate testing with an engine mounted on an engine dynamometer under 40 CFR 1037.551, such as for a selective enforcement audit as described in 40 CFR 1037.301. (6) For hybrid powertrains with no plug-in capability, correct for the net energy change of the energy storage device as described in 40 CFR 1066.501(a)(3). For plug-in hybrid electric powertrains, follow 40 CFR 1066.501(a)(3) to determine End-of-Test for charge-depleting operation. You must get our approval in advance for your utility factor curve; we will approve it if you can show that you created it, using good engineering judgment, from sufficient in-use data of vehicles in the same application as the vehicles in which the plug-in hybrid electric powertrain will be installed. You may use methodologies described in SAE J2841 to develop the utility factor curve. (7) The provisions related to carbon balance error verification in § 1036.543 apply for all testing in this section. These procedures are optional if you are only performing direct or indirect fuel-flow measurement, but we will perform carbon balance error verification for all testing under this section. (8) Do not apply accessory loads when conducting a powertrain test to generate inputs to GEM if torque is measured at the axle input shaft or wheel hubs. (9) If you test a powertrain over the Low Load Cycle specified in § 1036.514, control and apply the electrical accessory loads. We recommend using a load bank connected directly to the powertrain's electrical system. You may instead use an alternator with dynamic electrical load control. Use good engineering judgment to account for the efficiency of the alternator or the efficiency of the powertrain to convert the mechanical energy to electrical energy. (10) The following instruments are required with plug-in hybrid systems to determine required voltages and currents during testing and must be installed on the powertrain to measure these values during testing: (i) Measure the voltage and current of the battery pack directly with a DC wideband power analyzer to determine power. Measure all current entering and leaving the battery pack. Do not measure voltage upstream of this measurement point. The maximum integration period for determining amp-hours is 0.05 seconds. The power analyzer must have an accuracy for measuring current and voltage of 1% of point or 0.3% of maximum, whichever is greater. The power analyzer must not be susceptible to offset errors while measuring current. (ii) If safety considerations do not allow for measuring voltage, you may determine the voltage directly from the powertrain ECM. (11) The following figure provides an overview of testing under this section: Figure 1 to Paragraph (a)(11) of § 1036.545—Overview of Powertrain Testing (b) Test configuration. (1) The default test configuration consists of a powertrain with all components upstream of the axle. This involves connecting the powertrain's output shaft directly to the dynamometer or to a gear box with a fixed gear ratio and measuring torque at the axle input shaft. You may instead set up the dynamometer to connect at the wheel hubs and measure torque at that location. The preceding sentence may apply if your powertrain configuration requires it, such as for hybrid powertrains or if you want to represent the axle performance with powertrain test results. You may alternatively test the powertrain with a chassis dynamometer if you measure speed and torque at the powertrain's output shaft or wheel hubs. (2) For testing hybrid engines, connect the engine's crankshaft directly to the dynamometer and measure torque at that location. (c) Powertrain temperatures during testing. (d) Powertrain break in. (1) Break in the engine according to 40 CFR 1065.405(c). (2) Break in the axle assembly using good engineering judgment. Maintain gear oil temperature at or below 100 °C throughout the break-in period. (3) Break in the transmission using good engineering judgment. Maintain transmission oil temperature at (87 to 93) °C for automatic transmissions and transmissions having more than two friction clutches, and at (77 to 83) °C for all other transmissions. You may ask us to approve a different range of transmission oil temperatures if you have data showing that it better represents in-use operation. (e) Dynamometer setup. (f) Driveline and vehicle model. f nref,dyno (1) Driveline model with a transmission in hardware. f nref,dyno Eq. 1036.545-1 Where: k a[speed] a[speed] v refi r [speed] (2) Driveline model with a simulated transmission. f nref,dyno (i) The transmission submodel needs the following model inputs: (A) Torque measured at the engine's crankshaft. (B) Engine estimated torque determined from the electronic control module or by converting the instantaneous operator demand to an instantaneous torque in N·m. (C) Dynamometer mode when idling (speed-control or torque-control). (D) Measured engine speed when idling. (E) Transmission output angular speed, f ni,transmission Eq. 1036.545-2 Where: k a[speed] v refi r [speed] (ii) The transmission submodel generates the following model outputs: (A) Dynamometer target speed. (B) Dynamometer idle load. (C) Transmission engine load limit. (D) Engine speed target. (3) Vehicle model. refi Eq. 1036.545-3 Where: i Let v ref1 i T T Eff axle Eff axle T Eff axle T Use Eff axle M g 2 C rr G i -1 D i -1, i Eq. 1036.545-4 ρ ρ 3 C dA F brake, i -1 F grade i -1 M g G i -1 Eq. 1036.545-5 Δt Δt M rotating M rotating (4) Example. f nref,dyno k aB r B T 999 C rr −3 M C dA 2 G 999 F brake,999 v ref,999 F grade,999 Δ t M rotating v ref1000 (g) Driver model. (1) The driver model must meet the following speed requirements: (i) For operation over the highway cruise cycles, the speed requirements described in 40 CFR 1066.425(b) and (c). (ii) For operation over the Heavy-Duty Transient Test Cycle specified in 40 CFR part 1037, appendix A, the SET as defined § 1036.510, the Federal Test Procedure (FTP) as defined in § 1036.512, and the Low Load Cycle (LLC) as defined in § 1036.514, the speed requirements described in 40 CFR 1066.425(b) and (c). (iii) The exceptions in 40 CFR 1066.425(b)(4) apply to the highway cruise cycles, the Heavy-Duty Transient Test Cycle specified in 40 CFR part 1037, appendix A, SET, FTP, and LLC. (iv) If the speeds do not conform to these criteria, the test is not valid and must be repeated. (2) Send a brake signal when operator demand is zero and vehicle speed is greater than the reference vehicle speed from the test cycle. Include a delay before changing the brake signal to prevent dithering, consistent with good engineering judgment. (3) Allow braking only if operator demand is zero. (4) Compensate for the distance driven over the duty cycle over the course of the test. Use the following equation to perform the compensation in real time to determine your time in the cycle: Eq. 1036.545-6 Where: v vehicle v cycle v cycle, i -1 v cycle, i -1 v vehicle, i -1. (h) Vehicle configurations to evaluate for generating fuel maps as defined in § 1036.505. (1) For known vehicle configurations, use at least three equally spaced axle ratios or tire sizes and three different road loads (nine configurations), or at least four equally spaced axle ratios or tire sizes and two different road loads (eight configurations). Select axle ratios to represent the full range of expected vehicle installations. Select axle ratios and tire sizes such that the ratio of engine speed to vehicle speed covers the range of ratios of minimum and maximum engine speed to vehicle speed when the transmission is in top gear for the vehicles in which the powertrain will be installed. Note that you do not have to use the same axle ratios and tire sizes for each GEM regulatory subcategory. You may determine appropriate C rr C d A C rr, C d A (2) If vehicle configurations are not known, determine the vehicle model inputs for a set of vehicle configurations as described in § 1036.540(c)(3) with the following exceptions: (i) In the equations of § 1036.540(c)(3)(i), k topgear (ii) Test at least eight different vehicle configurations for powertrains that will be installed in Spark-ignition HDE, vocational Light HDV, and vocational Medium HDV using the following table instead of table 2 to paragraph (c)(3)(ii) of § 1036.540: Table 1 to Paragraph (h)(2)(ii) OF § 1036.545—Vehicle Configurations for Testing Spark-Ignition HDE, and Medium HDE (iii) Select and test vehicle configurations as described in § 1036.540(c)(3)(iii) for powertrains that will be installed in vocational Heavy HDV and tractors using the following tables instead of tables 3 and 4 to paragraph (c)(3)(iii) of § 1036.540: Table 2 to Paragraph (h)(2)(iii) of § 1036.545—Vehicle Configurations For Testing General Purpose Tractors and Vocational Heavy HDV Table 3 to Paragraph (h)(2)(iii) of § 1036.545—Vehicle Configurations For Testing Heavy HDE Installed in Heavy-Haul Tractors (3) For hybrid powertrain systems where the transmission will be simulated, use the transmission parameters defined in § 1036.540(c)(2) to determine transmission type and gear ratio. Use a fixed transmission efficiency of 0.95. The GEM HIL transmission model uses a transmission parameter file for each test that includes the transmission type, gear ratios, lockup gear, torque limit per gear from § 1036.540(c)(2), and the values from § 1036.505(b)(4) and (c). (i) [Reserved] (j) Duty cycles to evaluate. (1) Understand “engine” to mean “powertrain”. (2) Warm up the powertrain as described in § 1036.520(d). (3) Within 90 seconds after concluding the warm-up, start the transition to the preconditioning cycle as described in paragraph (j)(5) of this section. (4) For plug-in hybrid engines, precondition the battery and then complete all back-to-back tests for each vehicle configuration according to 40 CFR 1066.501(a)(3) before moving to the next vehicle configuration. The following figure illustrates a charge-depleting test sequence with engine operation during two duty cycles, which are used for criteria pollutant determination: Figure 2 to Paragraph (j)(4) of § 1036.545—Generic Charge-Depleting Test Sequence (5) If the preceding duty cycle does not end at 0 mi/hr, transition between duty cycles by decelerating at a rate of 2 mi/hr/s at 0% grade until the vehicle reaches zero speed. Shut off the powertrain. Prepare the powertrain and test cell for the next duty-cycle. (6) Start the next duty-cycle within 60 to 180 seconds after shutting off the powertrain. (i) To start the next duty-cycle, for hybrid powertrains, key on the vehicle and then start the duty-cycle. For conventional powertrains key on the vehicle, start the engine, wait for the engine to stabilize at idle speed, and then start the duty-cycle. (ii) If the duty-cycle does not start at 0 mi/hr, transition to the next duty cycle by accelerating at a target rate of 1 mi/hr/s at 0% grade. Stabilize for 10 seconds at the initial duty cycle conditions and start the duty-cycle. (7) Calculate cycle work using GEM or the speed and torque from the driveline and vehicle models from paragraph (f) of this section to determine the sequence of duty cycles. (8) Calculate the mass of fuel consumed for idle duty cycles as described in paragraph (n) of this section. (k) Measuring NO X emissions. X X X X X (l) [Reserved] (m) Measured output speed validation. nref Table 4 to Paragraph ( m Parameter a Speed control Slope, a 1 0.990 ≤ a 1 Absolute value of intercept, | a 0 ≤2.0% of maximum ƒ nref Standard error of the estimate, SEE ≤2.0% of maximum ƒ nref Coefficient of determination, r 2 ≥0.990. a nref,dyno (n) Fuel consumption at idle. (1) Direct fuel flow measurement. m fuelidle (2) Indirect fuel flow measurement. m fuelidle Eq. 1036.545-7 Where: M C w Cmeas w C n exh χ Ccombdry χ H2Oexhdry 2 m CO2DEF 2 M CO2 Example: M C w Cmeas n exh χ Ccombdry −3 χ H2Oexhdry −2 m CO2DEF M CO2 (o) Create GEM inputs. (1) Correct the measured or calculated fuel masses, m fuel[cycle] m fuelidle m fuel m fuel[cycle] (2) Declare fuel masses, m fuel[cycle] m fuelidle m fuel[cycle] m fuelidle (3) For engines designed for plug-in hybrid electric vehicles, the mass of fuel for each cycle, m fuel[cycle] m fuelUF[cycle] m fuel Eq. 1036.545-8 Where: i N m fuel[cycle]CD i i i UF DCD i D CD i i, i UF DCD0 j M m fuel[cycle]CS j j j UF RCD R CD, R CD N Eq. 1036.545-9 Where: k Q v k k v Δ t record ƒ record Example for the 55 mi/hr cruise cycle: Q y 1 y 2 y 3 ƒ record Δ t (4) For the transient cycle specified in 40 CFR 1037.510(a)(2)(i), calculate powertrain output speed per unit of vehicle speed using one of the following methods: (i) For testing with torque measurement at the axle input shaft: Eq. 1036.545-10 Example: (ii) For testing with torque measurement at the wheel hubs, use Eq. 1036.545-8 setting k a (iii) For testing with torque measurement at the engine's crankshaft: Eq. 1036.545-11 Where: f nengine v ref Example: (5) Calculate engine idle speed, by taking the average engine speed measured during the transient cycle test while the vehicle speed is below 0.100 m/s. (Note: Use all the charge-sustaining test intervals when determining engine idle speed for plug-in hybrid powertrains.) (6) For the cruise cycles specified in 40 CFR 1037.510(a)(2)(ii), calculate the average powertrain output speed, f npowertrain T powertrain f npowertrain T powertrain (7) Calculate positive work, W [cycle], W [cycle] W [cycle] (8) The following tables illustrate the GEM data inputs corresponding to the different vehicle configurations for a given duty cycle: (i) For the transient cycle: Table 5 to Paragraph (o)(8)(i) of § 1036.545—Example of Output Matrix for Transient Cycle Vehicle Configurations (ii) For the cruise cycles: Table 6 to Paragraph (o)(8)(ii) of § 1036.545—Generic Example of Output Matrix for Cruise Cycle Vehicle Configurations [89 FR 29752, Apr. 22, 2024; 89 FR 51236, June 17, 2024, as amended at 91 FR 7780, Feb. 18, 2026] § 1036.550 Calculating CO 2 This section describes how to calculate official emission results for CO 2 (a) Calculate brake-specific emission rates for each applicable duty cycle as specified in 40 CFR 1065.650. Apply infrequent regeneration adjustment factors as described in § 1036.580. (b) Adjust CO 2 (1) Determine your test fuel's mass-specific net energy content, E mfuelmeas, E mfuelmeas (i) For liquid fuels, determine E mfuelmeas E mfuelmeas E mfuelmeas. (ii) For gaseous fuels, determine E mfuelmeas (2) Determine your test fuel's carbon mass fraction, w C, α β (i) For liquid fuels, have the sample analyzed by at least three different labs, determine w C w C w C w C w C w C. (ii) For gaseous fuels, have the sample analyzed by a single lab and use that result as your test fuel's w C. (3) If, over a period of time, you receive multiple fuel deliveries from a single stock batch of test fuel, you may use constant values for mass-specific energy content and carbon mass fraction, consistent with good engineering judgment. To use these constant values, you must demonstrate that every subsequent delivery comes from the same stock batch and that the fuel has not been contaminated. (4) Correct measured CO 2 Where: e CO2 2 E mfuelmeas w Cmeas E mfuelCref E mfuelCref w Cmeas Example: e CO2 E mfuelmeas E mfuelCref w Cmeas e CO2cor Table 1 to Paragraph ( b Fuel type a Reference fuel carbon-mass-specific net energy content, E mfuelCref b Reference fuel carbon mass fraction, w Cref b Diesel fuel 49.3112 0.874 Gasoline 50.4742 0.846 Natural gas 66.2910 0.750 LPG 56.5218 0.820 Dimethyl ether 55.3886 0.521 High-level ethanol-gasoline blends 50.3211 0.576 a b E mfuelCref w Cref (c) Your official emission result for each pollutant equals your calculated brake-specific emission rate multiplied by all applicable adjustment factors, other than the deterioration factor. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29763, Apr. 22, 2024] § 1036.555 Test procedures to verify deterioration factors. Sections 1036.240 through 1036.246 describe certification procedures to determine, verify, and apply deterioration factors. This section describes the measurement procedures for verifying deterioration factors using PEMS with in-use vehicles. (a) Use PEMS to collect 1 Hz data throughout a shift-day of driving. Collect all the data elements needed to determine brake-specific emissions. Calculate emission results using moving average windows as described in § 1036.530. (b) Collect data as needed to perform the calculations specified in paragraph (a) of this section and to submit the test report specified in § 1036.246(d). § 1036.580 Infrequently regenerating aftertreatment devices. For engines using aftertreatment technology with infrequent regeneration events that may occur during testing, take one of the following approaches to account for the emission impact of regeneration: (a) You may use the calculation methodology described in 40 CFR 1065.680 to adjust measured emission results. Do this by developing an upward adjustment factor and a downward adjustment factor for each pollutant based on measured emission data and observed regeneration frequency as follows: (1) Adjustment factors should generally apply to an entire engine family, but you may develop separate adjustment factors for different configurations within an engine family. Use the adjustment factors from this section for all testing for the engine family. (2) You may use carryover data to establish adjustment factors for an engine family as described in § 1036.235(d), consistent with good engineering judgment. (3) Identify the value of F [cycle] (4) Calculate separate adjustment factors for each required duty cycle. (b) You may ask us to approve an alternate methodology to account for regeneration events. We will generally limit approval to cases where your engines use aftertreatment technology with extremely infrequent regeneration and you are unable to apply the provisions of this section. (c) You may choose to make no adjustments to measured emission results if you determine that regeneration does not significantly affect emission levels for an engine family (or configuration) or if it is not practical to identify when regeneration occurs. You may omit adjustment factors under this paragraph (c) for individual pollutants under this paragraph (c) as appropriate. If you choose not to make adjustments under paragraph (a) or (b) of this section, your engines must meet emission standards for all testing, without regard to regeneration. (d) If your engine family includes engines with one or more emergency AECDs approved under § 1036.115(h)(4), do not consider additional regenerations resulting from those AECDs when developing adjustments to measured values under paragraph (a) or (b) of this section. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29763, Apr. 22, 2024; 91 FR 7781, Feb. 18, 2026] Subpart G—Special Compliance Provisions § 1036.601 Overview of compliance provisions. (a) Engine and vehicle manufacturers, as well as owners, operators, and rebuilders of engines subject to the requirements of this part, and all other persons, must observe the provisions of this part, the provisions of 40 CFR part 1068, and the provisions of the Clean Air Act. The provisions of 40 CFR part 1068 apply for heavy-duty highway engines as specified in that part, subject to the following provisions: (1) The exemption provisions of 40 CFR 1068.201 through 1068.230, 1068.240, and 1068.260 through 265 apply for heavy-duty motor vehicle engines. The other exemption provisions, which are specific to nonroad engines, do not apply for heavy-duty vehicles or heavy-duty engines. (2) Engine signals to indicate a need for maintenance under § 1036.125(a)(1)(ii) are considered an element of design of the emission control system. Disabling, resetting, or otherwise rendering such signals inoperative without also performing the indicated maintenance procedure is therefore prohibited under 40 CFR 1068.101(b)(1). (3) The warranty-related prohibitions in section 203(a)(4) of the Act (42 U.S.C. 7522(a)(4)) apply to manufacturers of new heavy-duty highway engines in addition to the prohibitions described in 40 CFR 1068.101(b)(6). We may assess a civil penalty up to $44,539 for each engine or vehicle in violation. The civil monetary penalty amount listed in this section may not reflect recent inflation adjustments EPA is required to make. The current maximum and minimum statutory civil penalty amounts are located in § 19.4. (b) The following provisions from 40 CFR parts 85 and 86 continue to apply after December 20, 2026 for engines subject to the requirements of this part: (1) The tampering prohibition in 40 CFR 1068.101(b)(1) applies for alternative fuel conversions as specified in 40 CFR part 85, subpart F. (2) Engine manufacturers must meet service information requirements as specified in 40 CFR 86.010-38(j). (3) Provisions related to nonconformance penalties apply as described in 40 CFR part 86, subpart L. Note that nonconformance penalty provisions are not available for current or future emission standards unless we revise the regulation to specify how to apply those provisions. (4) The manufacturer-run in-use testing program described in 40 CFR part 86, subpart T, continues to apply for engines subject to exhaust emission standards under 40 CFR part 86. (c) The emergency vehicle field modification provisions of 40 CFR 85.1716 apply with respect to the standards of this part. Emergency vehicle field modifications under 40 CFR 85.1716 may include corresponding changes to diagnostic systems relative to the requirements in §§ 1036.110 and 1036.111. For example, the cab display required under § 1036.110(c)(1) identifying a fault condition may omit information about the timing or extent of a pending derate if an AECD will override the derate. (d) Subpart C of this part describes how to test and certify dual-fuel and flexible-fuel engines. Some multi-fuel engines may not fit either of those defined terms. For such engines, we will determine whether it is most appropriate to treat them as single-fuel engines, dual-fuel engines, or flexible-fuel engines based on the range of possible and expected fuel mixtures. For example, an engine might burn natural gas but initiate combustion with a pilot injection of diesel fuel. If the engine is designed to operate with a single fueling algorithm ( i.e., [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29763, Apr. 22, 2024; 89 FR 88656, Nov. 8, 2024] § 1036.605 Alternate emission standards for engines used in specialty vehicles. Starting in model year 2027, compression-ignition engines at or above 56 kW and spark-ignition engines of any size that will be installed in specialty vehicles as allowed by 40 CFR 1037.605 are exempt from the standards of subpart B of this part if they are certified under this part to alternate emission standards as follows: (a) Spark-ignition engines must be of a configuration that is identical to one that is certified under 40 CFR part 1048 to Blue Sky standards under 40 CFR 1048.140. (b) Compression-ignition engines must be of a configuration that is identical to one that is certified under 40 CFR part 1039, and must be certified with a family emission limit for PM of 0.020 g/kW-hr using the same duty cycles that apply under 40 CFR part 1039. (c) Except as specified in this section, engines certified under this section must meet all the requirements that apply under 40 CFR part 1039 or 1048 instead of the comparable provisions in this part. Before shipping engines under this section, you must have written assurance from vehicle manufacturers that they need a certain number of exempted engines under this section. In your annual production report under 40 CFR 1039.250 or 1048.250, count these engines separately and identify the vehicle manufacturers that will be installing them. Treat these engines as part of the corresponding engine family under 40 CFR part 1039 or part 1048 for compliance purposes such as testing production engines, in-use testing, defect reporting, and recall. (d) The engines must be labeled as described in § 1036.135, with the following statement instead of the one specified in § 1036.135(c)(8): “This engine conforms to alternate standards for specialty vehicles under 40 CFR 1036.605.” Engines certified under this section may not have the label specified for nonroad engines in 40 CFR part 1039 or 1048 or any other label identifying them as nonroad engines. (e) In a separate application for a certificate of conformity, identify the corresponding nonroad engine family, describe the label required under section, state that you meet applicable diagnostic requirements under 40 CFR part 1039 or 1048, and identify your projected U.S.-directed production volume. (f) No additional certification fee applies for engines certified under this section. (g) Engines certified under this section may not generate or use emission credits under this part or under 40 CFR part 1039. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29763, Apr. 22, 2024; 91 FR 7781, Feb. 18, 2026] § 1036.610 Off-cycle technology credits. (a) You may ask us to apply the provisions of this section for CO 2 2 (b) The provisions of this section may be applied as either an improvement factor (used to adjust emission results) or as a separate credit, consistent with good engineering judgment. Note that the term “credit” in this section describes an additive adjustment to emission rates and is not equivalent to an emission credit in the ABT program of subpart H of this part. We recommend that you base your credit/adjustment on A to B testing of pairs of engines/vehicles differing only with respect to the technology in question. (1) Calculate improvement factors as the ratio of in-use emissions with the technology divided by the in-use emissions without the technology. Adjust the emission results by multiplying by the improvement factor. Use the improvement-factor approach where good engineering judgment indicates that the actual benefit will be proportional to emissions measured over the procedures specified in this part. For example, the benefits from technologies that reduce engine operation would generally be proportional to the engine's emission rate. (2) Calculate separate credits based on the difference between the in-use emission rate (g/ton-mile) with the technology and the in-use emission rate without the technology. Subtract this value from your measured emission result and use this adjusted value to determine your FEL. We may also allow you to calculate the credits based on g/hp·hr emission rates. Use the separate-credit approach where good engineering judgment indicates that the actual benefit will not be proportional to emissions measured over the procedures specified in this part. (3) We may require you to discount or otherwise adjust your improvement factor or credit to account for uncertainty or other relevant factors. (c) Send your request to the Designated Compliance Officer. We recommend that you do not begin collecting data (for submission to EPA) before contacting us. For technologies for which the vehicle manufacturer could also claim credits (such as transmissions in certain circumstances), we may require you to include a letter from the vehicle manufacturer stating that it will not seek credits for the same technology. Your request must contain the following items: (1) A detailed description of the off-cycle technology and how it functions to reduce CO 2 (2) A list of the engine configurations that will be equipped with the technology. (3) A detailed description and justification of the selected engines. (4) All testing and simulation data required under this section, plus any other data you have considered in your analysis. You may ask for our preliminary approval of your plan under § 1036.210. (5) A complete description of the methodology used to estimate the off-cycle benefit of the technology and all supporting data, including engine testing and in-use activity data. Also include a statement regarding your recommendation for applying the provisions of this section for the given technology as an improvement factor or a credit. (6) An estimate of the off-cycle benefit by engine model, and the fleetwide benefit based on projected sales of engine models equipped with the technology. (7) A demonstration of the in-use durability of the off-cycle technology, based on any available engineering analysis or durability testing data (either by testing components or whole engines). (d) We may seek public comment on your request, consistent with the provisions of 40 CFR 86.1869-12(d). However, we will generally not seek public comment on credits/adjustments based on A to B engine dynamometer testing, chassis testing, or in-use testing. (e) We may approve an improvement factor or credit for any configuration that is properly represented by your testing. (1) For model years before 2021, you may continue to use an approved improvement factor or credit for any appropriate engine families in future model years through 2020. (2) For model years 2021 and later, you may not rely on an approval for model years before 2021. You must separately request our approval before applying an improvement factor or credit under this section for 2021 and later engines, even if we approved an improvement factor or credit for similar engine models before model year 2021. Note that approvals for model year 2021 and later may carry over for multiple years. § 1036.615 Engines with Rankine cycle waste heat recovery and hybrid powertrains. This section specifies how to generate advanced-technology emission credits for hybrid powertrains that include energy storage systems and regenerative braking (including regenerative engine braking) and for engines that include Rankine-cycle (or other bottoming cycle) exhaust energy recovery systems. This section applies only for model year 2020 and earlier engines. (a) Pre-transmission hybrid powertrains. (b) Rankine engines. (c) Calculating credits. (d) Off-cycle technologies. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29763, Apr. 22, 2024] § 1036.620 Alternate standards based on model year 2011 compression-ignition engines. For model years 2014 through 2016, you may certify your compression-ignition engines to alternate fuel consumption standards as described in this section. However, you may not certify engines to these alternate standards if they are part of an averaging set in which you carry a balance of banked credits. For purposes of this section, you are deemed to carry credits in an averaging set if you carry credits from advanced technology that are allowed to be used in that averaging set. (a) The standards of this section are determined from the measured emission rate of the engine of the applicable baseline 2011 engine family or families as described in paragraphs (b) and (c) of this section. Calculate the CO 2 (b) This paragraph (b) applies if you do not certify all your engine families in the averaging set to the alternate standards of this section. Identify separate baseline engine families for each engine family that you are certifying to the alternate standards of this section. For an engine family to be considered the baseline engine family, it must meet the following criteria: (1) It must have been certified to all applicable emission standards in model year 2011. If the baseline engine was certified to a NO X 2 X (i) Use the following equation to relate model year 2009-2011 NO X 2 2 a X b. (ii) For model year 2014-2016 engines certified to NO X 2 X (iii) Calculate separate adjustments for emissions over the SET duty cycle and the transient cycle. (2) The baseline configuration tested for certification must have the same engine displacement as the engines in the engine family being certified to the alternate standards, and its rated power must be within five percent of the highest rated power in the engine family being certified to the alternate standards. (3) The model year 2011 U.S.-directed production volume of the configuration tested must be at least one percent of the total 2011 U.S.-directed production volume for the engine family. (4) The tested configuration must have cycle-weighted BSFC equivalent to or better than all other configurations in the engine family. (c) This paragraph (c) applies if you certify all your engine families in the primary intended service class to the alternate standards of this section. For purposes of this section, you may combine Light HDE and Medium HDE into a single averaging set. Determine your baseline CO 2 2 X X X (d)-(e) [Reserved] (f) You need our approval before you may certify engines under this section, especially with respect to the numerical value of the alternate standards. We will not approve your request if we determine that you manipulated your engine families or engine configurations to certify to less stringent standards, or that you otherwise have not acted in good faith. You must keep and provide to us any information we need to determine that your engine families meet the requirements of this section. Keep these records for at least five years after you stop producing engines certified under this section. [88 FR 4487, Jan. 24, 2023, as amended at 91 FR 7781, Feb. 18, 2026] § 1036.630 Measurement of CO 2 For engines included in powertrain families under § 1036.231, you may choose to include the corresponding engine emissions in your engine families under this part instead of (or in addition to) the otherwise applicable engine fuel maps. (a) If you choose to certify powertrain fuel maps in an engine family for fuel consumption standards, the declared values for powertrain testing become the standards that apply for selective enforcement audits and in-use testing. We may require that you provide to us the engine cycle (not normalized) corresponding to a given powertrain for each of the specified duty cycles. (b) If you choose to certify only fuel map values for an engine family for fuel consumption standards and to not certify values over powertrain cycles under § 1036.545, we will not presume you are responsible for value over the powertrain cycles. However, where we determine that you are responsible in whole or in part for the emission exceedance in such cases, we may require that you participate in any recall of the affected vehicles. (c) If you split an engine family into subfamilies based on different fuel-mapping procedures as described in § 1036.230(f)(2), the fuel-mapping procedures you identify for certifying each subfamily also apply for selective enforcement audits and in-use testing. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29764, Apr. 22, 2024; 91 FR 7781, Feb. 18, 2026] § 1036.655 Special provisions for diesel-fueled engines sold in American Samoa or the Commonwealth of the Northern Mariana Islands. (a) The prohibitions in § 1068.101(a)(1) do not apply to diesel-fueled engines that are intended for use and will be used in American Samoa or the Commonwealth of the Northern Mariana Islands, subject to the following conditions: (1) The engine meets the emission standards that applied to model year 2006 engines as specified in appendix A of this part. (2) You meet all the requirements of 40 CFR 1068.265. (b) If you introduce an engine into U.S. commerce under this section, you must meet the labeling requirements in § 1036.135, but add the following statement instead of the compliance statement in § 1036.135(c)(8): THIS ENGINE (or VEHICLE, as applicable) CONFORMS TO US EPA EMISSION STANDARDS APPLICABLE TO MODEL YEAR 2006. THIS ENGINE (or VEHICLE, as applicable) DOES NOT CONFORM TO US EPA EMISSION REQUIREMENTS IN EFFECT AT TIME OF PRODUCTION AND MAY NOT BE IMPORTED INTO THE UNITED STATES OR ANY TERRITORY OF THE UNITED STATES EXCEPT AMERICAN SAMOA OR THE COMMONWEALTH OF THE NORTHERN MARIANA ISLANDS. (c) Introducing into U.S. commerce an engine exempted under this section in any state or territory of the United States other than American Samoa or the Commonwealth of the Northern Mariana Islands, throughout its lifetime, violates the prohibitions in 40 CFR 1068.101(a)(1), unless it is exempt under a different provision. (d) The exemption provisions in this section also applied for model year 2007 and later engines introduced into commerce in Guam before January 1, 2024. Subpart H—Averaging, Banking, and Trading for Certification § 1036.701 General provisions. (a) You may average, bank, and trade (ABT) emission credits for purposes of certification as described in this subpart and in subpart B of this part to show compliance with the standards of §§ 1036.104. Participation in this program is voluntary. Note that certification to NO X X (b) The definitions of subpart I of this part apply to this subpart in addition to the following definitions: (1) Actual emission credits (2) Averaging set (3) Broker (4) Buyer (5) Reserved emission credits (6) Seller (7) Standard (8) Trade (c) Emission credits may be exchanged only within an averaging set, except as specified in § 1036.740. (d) You may not use emission credits generated under this subpart to offset any emissions that exceed an FEL/FCL or standard. This paragraph (d) applies for all testing, including certification testing, in-use testing, selective enforcement audits, and other production-line testing. However, if emissions from an engine exceed an FEL/FCL or standard (for example, during a selective enforcement audit), you may use emission credits to recertify the engine family with a higher FEL/FCL that applies only to future production. (e) You may use either of the following approaches to retire or forego emission credits: (1) You may retire emission credits generated from any number of your engines. This may be considered donating emission credits to the environment. Identify any such credits in the reports described in § 1036.730. Engines must comply with the applicable FELs even if you donate or sell the corresponding emission credits. Donated credits may no longer be used by anyone to demonstrate compliance with any EPA emission standards. (2) You may certify an engine family using an FEL/FCL below the emission standard as described in this part and choose not to generate emission credits for that family. If you do this, you do not need to calculate emission credits for those engine families, and you do not need to submit or keep the associated records described in this subpart for that family. (f) Emission credits may be used in the model year they are generated. Surplus emission credits may be banked for future model years. Surplus emission credits may sometimes be used for past model years, as described in § 1036.745. (g) You may increase or decrease an FEL/FCL during the model year by amending your application for certification under § 1036.225. The new FEL/FCL may apply only to engines you have not already introduced into commerce. (h)-(j) [Reserved] (k) Engine families you certify with a nonconformance penalty under 40 CFR part 86, subpart L, may not generate emission credits. [88 FR 4487, Jan. 24, 2023, as amended at 91 FR 7781, Feb. 18, 2026] § 1036.705 Generating and calculating emission credits. (a) The provisions of this section apply for calculating NO X (b) For each participating family, calculate positive or negative emission credits relative to the otherwise applicable emission standard. Calculate positive emission credits for a family that has an FEL below the standard. Calculate negative emission credits for a family that has an FEL above the standard. Sum your positive and negative credits for the model year before rounding. Calculate emission credits to the nearest megagram (Mg) for each family using the following equation: Emission credits Std FL CF Volume UL c Where: Std X FL CF Volume UL c −9 Example for model year 2028 Heavy HDE generating NO X credits: Std FEL CF Volume UL c −9 Emission credits −9 Emission credits (c) Compliance with the requirements of this subpart is determined at the end of the model year by calculating emission credits based on actual production volumes, excluding the following engines: (1) Engines that you do not certify to the standards of this part because they are permanently exempted under subpart G of this part or under 40 CFR part 1068. (2) Exported engines. (3) Engines not subject to the requirements of this part, such as those excluded under § 1036.5. (4) Engines certified to state emission standards that are different than the emission standards referenced in this section, and intended for sale in a state that has adopted those emission standards. (5) Any other engines if we indicate elsewhere in this part that they are not to be included in the calculations of this subpart. [91 FR 7782, Feb. 18, 2026] § 1036.710 Averaging. (a) Averaging is the exchange of emission credits among your engine families. You may average emission credits only within the same averaging set, except as specified in § 1036.740. (b) You may certify one or more engine families to an FEL/FCL above the applicable standard, subject to any applicable FEL caps and other the provisions in subpart B of this part, if you show in your application for certification that your projected balance of all emission-credit transactions in that model year is greater than or equal to zero, or that a negative balance is allowed under § 1036.745 for NHTSA's fuel efficiency program. (c) If you certify an engine family to an FEL/FCL that exceeds the otherwise applicable standard, you must obtain enough emission credits to offset the engine family's deficit by the due date for the final report required in § 1036.730. The emission credits used to address the deficit may come from your other engine families that generate emission credits in the same model year (or from later model years as specified in § 1036.745), from emission credits you have banked, or from emission credits you obtain through trading. [88 FR 4487, Jan. 24, 2023, as amended at 91 FR 7782, Feb. 18, 2026] § 1036.715 Banking. (a) Banking is the retention of surplus emission credits by the manufacturer generating the emission credits for use in future model years for averaging or trading. (b) You may designate any emission credits you plan to bank in the reports you submit under § 1036.730 as reserved credits. During the model year and before the due date for the final report, you may designate your reserved emission credits for averaging or trading. (c) Reserved credits become actual emission credits when you submit your final report. However, we may revoke these emission credits if we are unable to verify them after reviewing your reports or auditing your records. (d) Banked credits retain the designation of the averaging set in which they were generated. § 1036.720 Trading. (a) Trading is the exchange of emission credits between manufacturers. You may use traded emission credits for averaging, banking, or further trading transactions. Traded emission credits remain subject to the averaging-set restrictions based on the averaging set in which they were generated. (b) You may trade actual emission credits as described in this subpart. You may also trade reserved emission credits, but we may revoke these emission credits based on our review of your records or reports or those of the company with which you traded emission credits. You may trade banked credits within an averaging set to any certifying manufacturer. (c) If a negative emission credit balance results from a transaction, both the buyer and seller are liable, except in cases we deem to involve fraud. See § 1036.255(e) for cases involving fraud. We may void the certificates of all engine families participating in a trade that results in a manufacturer having a negative balance of emission credits. See § 1036.745 for NHTSA's fuel efficiency program. [88 FR 4487, Jan. 24, 2023, as amended at 91 FR 7782, Feb. 18, 2026] § 1036.725 Required information for certification. (a) You must declare in your application for certification your intent to use the provisions of this subpart for each engine family that will be certified using the ABT program. You must also declare the FEL/FCL you select for the engine family for each pollutant for which you are using the ABT program. Your FELs must comply with the specifications of subpart B of this part, including the FEL caps. (b) Include the following in your application for certification: (1) A statement that, to the best of your belief, you will not have a negative balance of emission credits for any averaging set when all emission credits are calculated at the end of the year. For NHTSA's fuel efficiency program, you may include a statement that you will have a negative balance of emission credits for one or more averaging sets, but that it is allowed under § 1036.745. (2) Calculations of projected emission credits (positive or negative) based on projected production volumes as described in § 1036.705(c). We may require you to include similar calculations from your other engine families to project your net credit balances for the model year. If you project negative emission credits for a family, state the source of positive emission credits you expect to use to offset the negative emission credits. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29764, Apr. 22, 2024; 91 FR 7782, Feb. 18, 2026] § 1036.730 ABT reports. (a) If you certify any of your engine families using the ABT provisions of this subpart, you must send us a final report by September 30 following the end of the model year. (b) Your report must include the following information for each engine family participating in the ABT program: (1) Engine-family designation and averaging set. (2) The emission standards that would otherwise apply to the engine family. (3) The FEL/FCL for each pollutant. If you change the FEL/FCL after the start of production, identify the date that you started using the new FEL/FCL and/or give the engine identification number for the first engine covered by the new FEL/FCL. In this case, identify each applicable FEL/FCL and calculate the positive or negative emission credits as specified in § 1036.225(f). (4) The projected and actual production volumes for calculating emission credits for the model year. If you changed an FEL/FCL during the model year, identify the actual production volume associated with each FEL/FCL. (5) The transient cycle conversion factor for each engine configuration as described in § 1036.705. (6) Useful life. (7) Calculated positive or negative emission credits for the whole engine family. Identify any emission credits that you traded, as described in paragraph (d)(1) of this section. (c) Your report must include the following additional information: (1) Show that your net balance of emission credits from all your participating engine families in each averaging set in the applicable model year is not negative, except as allowed under § 1036.745 for NHTSA's fuel efficiency program. Your credit tracking must account for the limitation on credit life under § 1036.740(d). (2) State whether you will reserve any emission credits for banking. (3) State that the report's contents are accurate. (d) If you trade emission credits, you must send us a report within 90 days after the transaction, as follows: (1) As the seller, you must include the following information in your report: (i) The corporate names of the buyer and any brokers. (ii) A copy of any contracts related to the trade. (iii) The averaging set corresponding to the engine families that generated emission credits for the trade, including the number of emission credits from each averaging set. (2) As the buyer, you must include the following information in your report: (i) The corporate names of the seller and any brokers. (ii) A copy of any contracts related to the trade. (iii) How you intend to use the emission credits, including the number of emission credits you intend to apply for each averaging set. (e) Send your reports electronically to the Designated Compliance Officer using an approved information format. If you want to use a different format, send us a written request with justification for a waiver. (f) Correct errors in your report as follows: (1) If you notify us by the deadline for submitting the final report that errors mistakenly decreased your balance of emission credits, you may correct the errors and recalculate the balance of emission credits. (2) If you or we determine any time that errors mistakenly increased your balance of emission credits, you must correct the errors and recalculate the balance of emission credits. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29764, Apr. 22, 2024; 91 FR 7782, Feb. 18, 2026] § 1036.735 Recordkeeping. (a) You must organize and maintain your records as described in this section. We may review your records at any time. (b) Keep the records required by this section for at least eight years after the due date for the end-of-year report. You may not use emission credits for any engines if you do not keep all the records required under this section. You must therefore keep these records to continue to bank valid credits. Store these records in any format and on any media, as long as you can promptly send us organized, written records in English if we ask for them. You must keep these records readily available. We may review them at any time. (c) Keep a copy of the reports we require in §§ 1036.725 and 1036.730. (d) Keep appropriate records to document production volumes of engines that generate or use emission credits under the ABT program. For example, keep available records of the engine identification number (usually the serial number) for each engine you produce that generates or uses emission credits. You may identify these numbers as a range. If you change the FEL/FCL after the start of production, identify the date you started using each FEL/FCL and the range of engine identification numbers associated with each FEL/FCL. You must also identify the purchaser and destination for each engine you produce to the extent this information is available. (e) We may require you to keep additional records or to send us relevant information not required by this section in accordance with the Clean Air Act. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29764, Apr. 22, 2024] § 1036.740 Restrictions for using emission credits. The following restrictions apply for using emission credits: (a) Averaging sets. (1) Spark-ignition HDE. (2) Light HDE. (3) Medium HDE. (4) Heavy HDE. (b)-(c) [Reserved] (d) Credit life. X (e) Other restrictions. [88 FR 4487, Jan. 24, 2023, as amended at 91 FR 7782, Feb. 18, 2026] § 1036.745 End-of-year credit deficits. See 49 CFR 535.7 for provisions related to credit deficits for NHTSA's fuel consumption credits. [91 FR 7782, Feb. 18, 2026] § 1036.750 Consequences for noncompliance. (a) For each engine family participating in the ABT program, the certificate of conformity is conditioned upon full compliance with the provisions of this subpart during and after the model year. You are responsible to establish to our satisfaction that you fully comply with applicable requirements. We may void the certificate of conformity for an engine family if you fail to comply with any provisions of this subpart. (b) You may certify your engine family to an FEL above an applicable standard based on a projection that you will have enough emission credits to offset the deficit for the engine family. (c) We may void the certificate of conformity for an engine family if you fail to keep records, send reports, or give us information we request. Note that failing to keep records, send reports, or give us information we request is also a violation of 42 U.S.C. 7522(a)(2). (d) You may ask for a hearing if we void your certificate under this section (see § 1036.820). § 1036.755 Information provided to the Department of Transportation. After receipt of each manufacturer's final report as specified in § 1036.730 and completion of any verification testing required to validate the manufacturer's submitted final data, we will issue a report to the Department of Transportation with CO 2 [91 FR 7782, Feb. 18, 2026] Subpart I—Definitions and Other Reference Information § 1036.801 Definitions. The following definitions apply to this part. The definitions apply to all subparts unless we note otherwise. All undefined terms have the meaning the Act gives to them. The definitions follow: Act Adjustable parameter Advanced technology Aftertreatment Aircraft Alcohol-fueled engine Automated manual transmission (AMT) Automatic transmission (AT) Auxiliary emission control device Averaging set Axle ratio or Drive axle ratio (k a ) Calibration Carbon-containing fuel Carryover Certification Certified emission level Charge-depleting Charge-sustaining Complete vehicle Compression-ignition Crankcase emissions Critical emission-related component Defeat device Designated Compliance Officer (1) For engines subject to compression-ignition standards, Designated Compliance Officer [email protected]; www.epa.gov/ve-certification. (2) For engines subject to spark-ignition standards, Designated Compliance Officer [email protected]; www.epa.gov/ve-certification. Deteriorated emission level deteriorated emission level Deterioration factor (1) For multiplicative deterioration factors, the ratio of emissions at the end of useful life (or point of highest emissions) to emissions at the low-hour point. (2) For additive deterioration factors, the difference between emissions at the end of useful life (or point of highest emissions) and emissions at the low-hour point. Diesel exhaust fluid (DEF) X Diesel exhaust fluid Drive idle Dual-fuel Electronic control module (ECM) Emergency vehicle (1) It is an ambulance or a fire truck. (2) It is a vehicle that we have determined will likely be used in emergency situations where emission control function or malfunction may cause a significant risk to human life. For example, we would consider a truck that is certain to be retrofitted with a slip-on firefighting module to become an emergency vehicle, even though it was not initially designed to be a fire truck. Also, a mobile command center that is unable to manually regenerate its DPF while on duty could be an emergency vehicle. In making this determination, we may consider any factor that has an effect on the totality of the actual risk to human life. For example, we may consider how frequently a vehicle will be used in emergency situations or how likely it is that the emission controls will cause a significant risk to human life when the vehicle is used in emergency situations. We would not consider the truck in the example above to be an emergency vehicle if there is merely a possibility (rather than a certainty) that it will be retrofitted with a slip-on firefighting module. Emission control system Emission-data engine Emission-related component Emission-related maintenance Engine configuration Engine family Excluded (1) An engine that has been determined not to be a heavy-duty engine is excluded from this part. (2) Certain heavy-duty engines are excluded from the requirements of this part under § 1036.5. (3) Specific regulatory provisions of this part may exclude a heavy-duty engine generally subject to this part from one or more specific standards or requirements of this part. Exempted Exhaust gas recirculation Family certification level (FCL) 2 Family emission limit (FEL) (1) For NO X family emission limit X (2) For NHTSA's fuel efficiency program under 49 CFR part 535, family emission limit 2 2 Federal Test Procedure (FTP) Final drive ratio (k d ) final drive ratio Flexible-fuel Fuel type Gear ratio or Transmission gear ratio (k g ) Good engineering judgment Greenhouse gas Emissions Model (GEM) Gross vehicle weight rating (GVWR) Heavy-duty engine Heavy-duty vehicle Curb weight basic vehicle frontal area Hybrid Hydrocarbon (HC) Identification number Incomplete vehicle Innovative technology Liquefied petroleum gas (LPG) Low-hour X Manual transmission (MT) Manufacture Manufacturer Medium-duty passenger vehicle Model year Motorcoach Motor vehicle Natural gas Neat New motor vehicle engine (1) A motor vehicle engine for which the ultimate purchaser has never received the equitable or legal title is a new motor vehicle engine. new motor vehicle engine (2) An imported motor vehicle engine is a new motor vehicle engine (3) Any motor vehicle engine installed in a new motor vehicle. Noncompliant engine Nonconforming engine Nonmethane hydrocarbon (NMHC) Nonmethane hydrocarbon equivalent (NMHCE) Nonmethane nonethane hydrocarbon equivalent (NMNEHC) Off-cycle technology Official emission result Owners manual Oxides of nitrogen Percent Placed into service Preliminary approval Primary intended service class Rechargeable Energy Storage System (RESS) Relating to Revoke Round Sample Scheduled maintenance Small manufacturer Spark-ignition Stop-start Steady-state Suspend Test engine Tractor Ultimate purchaser United States Upcoming model year U.S.-directed production volume Vehicle Vocational vehicle Void We (us, our) [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29764, Apr. 22, 2024; 91 FR 7783, Feb. 18, 2026] § 1036.805 Symbols, abbreviations, and acronyms. The procedures in this part generally follow either the International System of Units (SI) or the United States customary units, as detailed in NIST Special Publication 811 (incorporated by reference, see § 1036.810). See 40 CFR 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 chemical species. Table 1 to Paragraph ( a Symbol Species C carbon. CO carbon monoxide. CO 2 carbon dioxide. H 2 water. HC hydrocarbon. NMHC nonmethane hydrocarbon. NMHCE nonmethane hydrocarbon equivalent. NMNEHC nonmethane nonethane hydrocarbon. NO nitric oxide. NO 2 nitrogen dioxide. NO X oxides of nitrogen. PM particulate matter. (b) Symbols for quantities. Table 2 to Paragraph ( b Symbol Quantity Unit Unit symbol Unit in terms of SI base units α atomic hydrogen-to-carbon ratio mole per mole mol/mol 1 Α Area square meter m 2 m 2 β atomic oxygen-to-carbon ratio mole per mole mol/mol 1 C d drag area meter squared m 2 m 2 C rr coefficient of rolling resistance newton per kilonewton N/kN 10 − 3 D distance miles or meters mi or m m e efficiency ∈ Difference or error quantity E mass weighted emission result grams/ton-mile g/ton-mi g/kg-km Eff efficiency E m mass-specific net energy content megajoules/kilogram MJ/kg m 2 − 2 f n angular speed (shaft) revolutions per minute r/min π·30·s − 1 g gravitational acceleration meters per second squared m/s 2 m·s − 2 i indexing variable k a drive axle ratio 1 k topgear highest available transmission gear m Mass pound mass or kilogram lbm or kg kg M molar mass gram per mole g/mol 10 − 3 − 1 M total number in a series M vehicle mass kilogram kg kg M rotating inertial mass of rotating components kilogram kg kg N total number in a series Q total number in a series P Power kilowatt kW 10 3 2 − 3 ρ mass density kilogram per cubic meter kg/m 3 m − 3 r tire radius meter m m SEE standard error of the estimate σ standard deviation T torque (moment of force) newton meter N·m m 2 − 2 t Time second s s Δt time interval, period, 1/frequency second s s UF utility factor v Speed miles per hour or meters per second mi/hr or m/s m·s − 1 W Work kilowatt-hour kW·hr 3.6·m 2 − 1 w C carbon mass fraction gram/gram g/g 1 w CH4N2O urea mass fraction gram/gram g/g 1 x amount of substance mole fraction mole per mole mol/mol 1 x b brake energy fraction x bl brake energy limit (c) Superscripts. Table 3 to Paragraph ( c Superscript Meaning overbar (such as y arithmetic mean. overdot (such as y quantity per unit time. (d) Subscripts. Table 4 to Paragraph ( d Subscript Meaning 65 65 miles per hour. A A speed. a absolute ( e.g., acc accessory. app approved. axle axle. B B speed. C C speed. C carbon mass. Ccombdry carbon from fuel per mole of dry exhaust. CD charge-depleting. CO 2 CO 2 comb combustion. comp composite. cor corrected. CS charge-sustaining. cycle cycle. D distance. D D speed. DEF diesel exhaust fluid. engine engine. exh raw exhaust. front frontal. fuel fuel. H 2 H 2 hi high. i an individual of a series. idle idle. int test interval. j an individual of a series. k an individual of a series. m mass. max maximum. mapped mapped. meas measured quantity. MY model year. neg negative. pos positive. R range. r relative ( e.g., rate rate (divided by time). rated rated. record record. ref reference quantity. speed speed. stall stall. test test. tire tire. transient transient. µ vector. UF utility factor. vehicle vehicle. (e) Other acronyms and abbreviations. Table 5 to Paragraph ( e Acronym Meaning ABT averaging, banking, and trading. AECD auxiliary emission control device. ASTM American Society for Testing and Materials. BTU British thermal units. CD charge-depleting. CFR Code of Federal Regulations. CI compression-ignition. COV coefficient of variation. CS charge-sustaining. DEF diesel exhaust fluid. DF deterioration factor. DOT Department of Transportation. DPF diesel particulate filter. E85 gasoline blend including nominally 85 percent denatured ethanol. ECM Electronic Control Module. EGR exhaust gas recirculation. EPA Environmental Protection Agency. FCL Family Certification Level. FEL family emission limit. FTP Federal Test Procedure. GCWR gross combined weight rating. GEM Greenhouse gas Emissions Model. g/hp·hr grams per brake horsepower-hour. GPS global positioning system. GVWR gross vehicle weight rating. Heavy HDE heavy heavy-duty engine (see § 1036.140). Heavy HDV heavy heavy-duty vehicle (see 40 CFR 1037.140). Light HDE light heavy-duty engine (see § 1036.140). Light HDV light heavy-duty vehicle (see 40 CFR 1037.140). LLC Low Load Cycle. LPG liquefied petroleum gas. Medium HDE medium heavy-duty engine (see § 1036.140). Medium HDV medium heavy-duty vehicle (see 40 CFR 1037.140). NARA National Archives and Records Administration. NHTSA National Highway Traffic Safety Administration. NTE not-to-exceed. PEMS portable emission measurement system. RESS rechargeable energy storage system. SCR selective catalytic reduction. SEE standard error of the estimate. SET Supplemental Emission Test. Spark-ignition HDE spark-ignition heavy-duty engine (see § 1036.140). SI spark-ignition. UL useful life. U.S United States. U.S.C United States Code. (f) Constants. Table 6 to Paragraph ( f Symbol Quantity Value g gravitational constant 9.80665 m·s − 2 R molar gas constant 8.314472 J/(mol·K) (m 2 − 2 − 1 − 1 (g) Prefixes. Table 7 to Paragraph ( g Symbol Quantity Value µ micro 10 − 6 m milli 10 − 3 c centi 10 − 2 k kilo 10 3 M mega 10 6 [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29765, Apr. 22, 2024; 91 FR 7786, Feb. 18, 2026] § 1036.810 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 International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959; (877) 909-2786; www.astm.org (1) ASTM D975-22, Standard Specification for Diesel Fuel, approved October 1, 2022 (“ASTM D975”); IBR approved for § 1036.415(c). (2) ASTM D3588-98 (Reapproved 2017)e1, Standard Practice for Calculating Heat Value, Compressibility Factor, and Relative Density of Gaseous Fuels, approved April 1, 2017 (“ASTM D3588”); IBR approved for § 1036.550(b). (3) ASTM D4809-18, Standard Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method), approved July 1, 2018 (“ASTM D4809”); IBR approved for § 1036.550(b). (4) ASTM D4814-21c, Standard Specification for Automotive Spark-Ignition Engine Fuel, approved December 15, 2021 (“ASTM D4814”); IBR approved for § 1036.415(c). (5) ASTM D7467-20a, Standard Specification for Diesel Fuel Oil, Biodiesel Blend (B6 to B20), approved June 1, 2020 (“ASTM D7467”); IBR approved for § 1036.415(c). (b) National Institute of Standards and Technology (NIST), 100 Bureau Drive, Stop 1070, Gaithersburg, MD 20899-1070; (301) 975-6478; www.nist.gov (1) NIST Special Publication 811, 2008 Edition, Guide for the Use of the International System of Units (SI), Physics Laboratory, March 2008; IBR approved for § 1036.805. (2) [Reserved] (c) SAE International, 400 Commonwealth Dr., Warrendale, PA 15096-0001; (877) 606-7323 (U.S. and Canada) or (724) 776-4970 (outside the U.S. and Canada); www.sae.org: (1) SAE J1979-2 APR2021, E/E Diagnostic Test Modes: OBDonUDS, Issued April 2021, (“SAE J1979-2”); IBR approved for § 1036.150(v). (2) [Reserved] (d) State of California, Office of Administrative Law, 300 Capitol Mall, Suite 1250, Sacramento, CA 95814-4339; 916-323-6815; [email protected]; www.oal.ca.gov/publications/ccr (1) 2019 13 CCR 1968.2, Title 13. Motor Vehicles, Division 3. Air Resources Board, Chapter 1. Motor Vehicle Pollution Control Devices, Article 2. Approval of Motor Vehicle Pollution Control Devices (New Vehicles), § 1968.2. Malfunction and Diagnostic System Requirements—2004 and Subsequent Model-Year Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles and Engines, operative October 3, 2019 “13 CCR 1968.2”; into §§ 1036.110(b); 1036.111(a). (2) 2019 13 CCR 1968.5, Title 13. Motor Vehicles, Division 3. Air Resources Board, Chapter 1. Motor Vehicle Pollution Control Devices, Article 2. Approval of Motor Vehicle Pollution Control Devices (New Vehicles), § 1968.5. Enforcement of Malfunction and Diagnostic System Requirements for 2004 and Subsequent Model-Year Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles and Engines, operative July 25, 2016 “13 CCR 1968.5”; into § 1036.110(b). (3) 2019 13 CCR 1971.1, Title 13. Motor Vehicles, Division 3. Air Resources Board, Chapter 1. Motor Vehicle Pollution Control Devices, Article 2. Approval of Motor Vehicle Pollution Control Devices (New Vehicles), § 1971.1. On-Board Diagnostic System Requirements—2010 and Subsequent Model-Year Heavy-Duty Engines, operative October 3, 2019 “13 CCR 1971.1”; into §§ 1036.110(b); 1036.111(a); 1036.150(v). (4) 13 CA ADC 1971.5: 2019 CA REG TEXT 504962 (NS), 13 CA ADC 1971.5. Enforcement of Malfunction and Diagnostic System Requirements for 2010 and Subsequent Model-Year Heavy-Duty Engines, operative October 3, 2019 “13 CCR 1971.5”; into § 1036.110(b). (e) U.S. EPA, Office of Air and Radiation, 2565 Plymouth Road, Ann Arbor, MI 48105; www.epa.gov; [email protected] (1) Greenhouse gas Emissions Model (GEM) Phase 2, Version 4.0, April 2022 (“GEM Phase 2, Version 4.0”); IBR approved for § 1036.545(a). (2) [Reserved] [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29765, Apr. 22, 2024] § 1036.815 Confidential information. (a) The provisions of 40 CFR 1068.10 and 1068.11 apply for information you submit under this part. (b) Emission data or information that is publicly available cannot be treated as confidential business information as described in 40 CFR 1068.11. Data that vehicle manufacturers need for demonstrating compliance with standards, including fuel-consumption data as described in §§ 1036.535 and 1036.545, also qualify as emission data for purposes of confidentiality determinations. [88 FR 4487, Jan. 24, 2023, as amended at 89 FR 29765, Apr. 22, 2024; 91 FR 7786, Feb. 18, 2026] § 1036.820 Requesting a hearing. (a) You may request a hearing under certain circumstances, as described elsewhere in this part. To do this, you must file a written request, including a description of your objection and any supporting data, within 30 days after we make a decision. (b) For a hearing you request under the provisions of this part, we will approve your request if we find that your request raises a substantial factual issue. (c) If we agree to hold a hearing, we will use the procedures specified in 40 CFR part 1068, subpart G. § 1036.825 Reporting and recordkeeping requirements. (a) This part includes various requirements to submit and record data or other information. Unless we specify otherwise, store required records in any format and on any media and keep them readily available for eight years after you send an associated application for certification, or eight years after you generate the data if they do not support an application for certification. We may review these records at any time. You must promptly give us organized, written records in English if we ask for them. We may require you to submit written records in an electronic format. (b) The regulations in § 1036.255 and 40 CFR 1068.25 and 1068.101 describe your obligation to report truthful and complete information. This includes information not related to certification. Failing to properly report information and keep the records we specify violates 40 CFR 1068.101(a)(2), which may involve civil or criminal penalties. (c) Send all reports and requests for approval to the Designated Compliance Officer (see § 1036.801). (d) Any written information we require you to send to or receive from another company is deemed to be a required record under this section. Such records are also deemed to be submissions to EPA. Keep these records for eight years unless the regulations specify a different period. We may require you to send us these records whether or not you are a certificate holder. (e) Under the Paperwork Reduction Act (44 U.S.C. 3501 et seq. (1) We specify the following requirements related to engine certification in this part: (i) In § 1036.135 we require engine manufacturers to keep certain records related to duplicate labels sent to vehicle manufacturers. (ii) In § 1036.150 we include various reporting and recordkeeping requirements related to interim provisions. (iii) In subpart C of this part we identify a wide range of information required to certify engines. (iv) In §§ 1036.430 and 1036.435 we identify reporting and recordkeeping requirements related to field testing in-use engines. (v) In subpart G of this part we identify several reporting and recordkeeping items for making demonstrations and getting approval related to various special compliance provisions. (vi) In §§ 1036.725, 1036.730, and 1036.735 we specify certain records related to averaging, banking, and trading. (2) We specify the following requirements related to testing in 40 CFR part 1065: (i) In 40 CFR 1065.2 we give an overview of principles for reporting information. (ii) In 40 CFR 1065.10 and 1065.12 we specify information needs for establishing various changes to published procedures. (iii) In 40 CFR 1065.25 we establish basic guidelines for storing information. (iv) In 40 CFR 1065.695 we identify the specific information and data items to record when measuring emissions. (3) We specify the following requirements related to the general compliance provisions in 40 CFR part 1068: (i) In 40 CFR 1068.5 we establish a process for evaluating good engineering judgment related to testing and certification. (ii) In 40 CFR 1068.25 we describe general provisions related to sending and keeping information (iii) In 40 CFR 1068.27 we require manufacturers to make engines available for our testing or inspection if we make such a request. (iv) In 40 CFR 1068.105 we require vehicle manufacturers to keep certain records related to duplicate labels from engine manufacturers. (v) In 40 CFR 1068.120 we specify recordkeeping related to rebuilding engines. (vi) In 40 CFR part 1068, subpart C, we identify several reporting and recordkeeping items for making demonstrations and getting approval related to various exemptions. (vii) In 40 CFR part 1068, subpart D, we identify several reporting and recordkeeping items for making demonstrations and getting approval related to importing engines. (viii) In 40 CFR 1068.450 and 1068.455 we specify certain records related to testing production-line engines in a selective enforcement audit. (ix) In 40 CFR 1068.501 we specify certain records related to investigating and reporting emission-related defects. (x) In 40 CFR 1068.525 and 1068.530 we specify certain records related to recalling nonconforming engines. (xi) In 40 CFR part 1068, subpart G, we specify certain records for requesting a hearing. Appendix A to Part 1036—Summary of Previous Emission Standards The following standards, which EPA originally adopted under 40 CFR part 85 or part 86, apply to compression-ignition engines produced before model year 2007 and to spark-ignition engines produced before model year 2008: (a) Smoke. (1) Engines were subject to the following smoke standards for model years 1970 through 1973: (i) 40 percent during the engine acceleration mode. (ii) 20 percent during the engine lugging mode. (2) The smoke standards in 40 CFR 86.007-11 started to apply in model year 1974. (b) Idle CO. (1) Spark-ignition engines with aftertreatment starting in model year 1987. This standard applied only for gasoline-fueled engines through model year 1997. Starting in model year 1998, the same standard applied for engines fueled by methanol, LPG, and natural gas. The idle CO standard no longer applied for engines certified to meet onboard diagnostic requirements starting in model year 2005. (2) Methanol-fueled compression-ignition engines starting in model year 1990. This standard also applied for natural gas and LPG engines starting in model year 1997. The idle CO standard no longer applied for engines certified to meet onboard diagnostic requirements starting in model year 2007. (c) Crankcase emissions. (1) Spark-ignition engines starting in model year 1968. This standard applied only for gasoline-fueled engines through model year 1989, and applied for spark-ignition engines using other fuels starting in model year 1990. (2) Naturally aspirated diesel-fueled engines starting in model year 1985. (3) Methanol-fueled compression-ignition engines starting in model year 1990. (4) Naturally aspirated gaseous-fueled engines starting in model year 1997, and all other gaseous-fueled engines starting in 1998. (d) Early steady-state standards. Table 1 of Appendix A—Early Steady-State Emission Standards for Heavy-Duty Engines Model year Fuel Pollutant HC NO X CO 1970-1973 gasoline 275 ppm 1.5 volume percent. 1974-1978 gasoline and diesel 16 g/hp·hr 40 g/hp·hr. 1979-1984 a gasoline and diesel 5 g/hp·hr for diesel; 5.0 g/hp·hr for gasoline 25 g/hp·hr. a X (e) Transient emission standards for spark-ignition engines. X X Table 2 of Appendix A—Transient Emission Standards for Spark-Ignition Engines a b Model year Pollutant HC CO NO X NO X 1985-1987 1.1 14.4 10.6 1988-1990 1.1 14.4 6.0 1991-1997 1.1 14.4 5.0 1998-2004 c 1.1 14.4 4.0 2005-2007 14.4 d a b c X d X X (f) Transient emission standards for compression-ignition engines. X X Table 3 of Appendix A—Transient Emission Standards for Compression-Ignition Engines a Model year Pollutant HC CO NO X NO X PM 1985-1987 1.3 15.5 10.7 1988-1989 1.3 15.5 10.7 0.60 1990 1.3 15.5 6.0 0.60 1991-1992 1.3 15.5 5.0 0.25 1993 1.3 15.5 5.0 0.25 truck, 0.10 bus. 1994-1995 1.3 15.5 5.0 0.10 truck, 0.07 urban bus. 1996-1997 1.3 15.5 5.0 0.10 truck, 0.05 urban bus. b 1998-2003 1.3 15.5 4.0 0.10 truck, 0.05 urban bus. b 2004-2006 15.5 c 0.10 truck, 0.05 urban bus. b a b c X Appendix B to Part 1036—Transient Duty Cycles (a) This appendix specifies transient test intervals and duty cycles for the engine and powertrain testing described in §§ 1036.512 and 1036.514, as follows: (1) The transient test intervals and duty cycle for testing engines involves a schedule of normalized engine speed and torque values. (2) The transient test intervals and duty cycles for powertrain testing involves a schedule of vehicle speeds and road grade. Determine road grade at each point based on the peak rated power of the powertrain system, P rated, Road grade P 2 rated b P rated c (3) The operating schedules in this appendix in some cases eliminate repetitive information by omitting 1 Hz records where there is no change in values. Perform testing by continuing to operate at the last specified values until the operating schedule shows a change in values. The official operating schedule for testing, cycle validation, and other purposes includes both the specified and omitted values. (b) The following transient test interval applies for spark-ignition engines and powertrains when testing over the duty cycle specified in § 1036.512: Table 1 of Appendix B—Transient Test Interval for Spark-Ignition Engines and Powertrains Under § 1036.512 (c) The following transient test interval applies for compression-ignition engines and powertrains when testing over the duty cycle specified in § 1036.512: Table 2 of Appendix B—Transient Test Interval for Compression-Ignition Engines and Powertrains Under § 1036.512 (d) The following transient duty cycle applies for compression-ignition engines and powertrains when testing under § 1036.514: Table 3 of Appendix B—Transient Duty Cycle for Compression-Ignition Engines and Powertrains Under § 1036.514 Appendix C of Part 1036—Default Engine Fuel Maps for § 1036.540 GEM contains the default steady-state fuel maps in this appendix for performing cycle-average engine fuel mapping as described in § 1036.505(b)(2). Note that manufacturers have the option to replace these default values in GEM if they generate a steady-state fuel map as described in § 1036.535(b). (a) Use the following default fuel map for compression-ignition engines that will be installed in Tractors and Vocational Heavy HDV: Table 1 of Appendix C—Default Fuel Map for Compression-Ignition Engines Installed in Tractors and Vocational Heavy HDV (b) Use the following default fuel map for compression-ignition engines that will be installed in Vocational Light HDV and Vocational Medium HDV: Table 2 of Appendix C—Default Fuel Map for Compression-Ignition Engines Installed in Vocational Light HDV and Vocational Medium HDV (c) Use the following default fuel map for all spark-ignition engines: Table 3 of Appendix C—Default Fuel Map for Spark-Ignition Engines

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