This section describes the applicable NOX, HC, CO, and PM standards for model years 2027 and later. These standards apply equally for all primary intended service classes unless otherwise noted.

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(a) Emission standards. Exhaust emissions may not exceed the standards in this section, as follows:

(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)(1) of § 1036.104—Compression-Ignition Standards for Duty Cycle Testing

Duty cycleNOX mg/hp·hrHC mg/hp·hrPM mg/hp·hrCO g/hp·hr
SET and FTP356056.0
LLC5014056.0

(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)(2) of § 1036.104—Spark-Ignition Standards for Duty Cycle Testing

Duty cycleNOX mg/hp·hrHC mg/hp·hrPM mg/hp·hrCO g/hp·hr
SET3560514.4
FTP356056.0

(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)(3) of § 1036.104—Compression-Ignition Standards for Off-Cycle Testing

Off-cycle BinNOXTemperature adjustment aHC mg/hp·hrPM mg/hp·hrCO g/hp·hr
Bin 110.0 g/hr(25.0?Tamb) · 0.25
Bin 258 mg/hp·hr(25.0?Tamb) · 2.21207.59

a Tamb is the mean ambient temperature over a shift-day, or equivalent. Adjust the off-cycle NOX standard for Tamb below 25.0 °C by adding the calculated temperature adjustment to the specified NOX standard. Round the temperature adjustment to the same precision as the NOX standard for the appropriate bin. If you declare a NOX FEL for the engine family, do not apply the FEL scaling calculation from paragraph (c)(3) of this section to the calculated temperature adjustment.

(b) Clean Idle. You may optionally certify compression-ignition engines to the Clean Idle NOX emission standard using the Clean Idle test specified in § 1036.525. The optional Clean Idle NOX emission standard is 30.0 g/h for model years 2024 through 2026, and 10.0 g/hr for model year 2027 and later. The standard applies separately to each mode of the Clean Idle test. If you certify an engine family to the Clean Idle standards, it is subject to all these voluntary standards as if they were mandatory.

(c) Averaging, banking, and trading. You may generate or use emission credits under the averaging, banking, and trading (ABT) program described in subpart H of this part for demonstrating compliance with NOX emission standards in paragraph (a) of this section. You must meet the PM, HC, and CO emission standards in § 1036.104(a) without generating or using emission credits.

(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, FELFTP, expressed to the same number of decimal places as the emission standard. Use FELFTP to calculate emission credits in subpart H of this part.

(2) The following NOX FEL caps are the maximum value you may specify for FELFTP:

(i) 65 mg/hp·hr for model years 2027 through 2030.

(ii) 50 mg/hp·hr for model year 2031 and later.

(iii) 70 mg/hp·hr for model year 2031 and later Heavy HDE.

(3) Calculate the NOX family emission limit, FEL[cycle]NOX, that applies for each duty-cycle or off-cycle standard using the following equation:

Where:Std[cycle]NOX, = the NOX emission standard that applies for the applicable cycle or for off-cycle testing under paragraph (a) of this section for engines not participating in the ABT program.FELFTPNOX = the engine family’s declared FEL for NOX over the FTP duty cycle from paragraph (c)(1) of this section.StdFTPNOX = the NOX emission standard that applies for the FTP duty cycle under paragraph (a) of this section for engines not participating in the ABT program.Example for model year 2029 Medium HDE for the SET:StdSETNOX = 35 mg/hp·hrFELFTP = 121 mg/hp·hrStdFTPNOX = 35 mg/hp·hrFELSETNOX = 121 mg/hp·hr

(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. The exhaust emission standards in this section apply for engines using the fuel type on which the engines in the engine family are designed to operate. You must meet the numerical emission standards for HC in this section based on the following types of hydrocarbon emissions for engines powered by the following fuels:

(1) Alcohol-fueled engines: NMHCE emissions.

(2) Gaseous-fueled engines: NMNEHC emissions.

(3) Other engines: NMHC emissions.

(e) Useful life. The exhaust emission standards of this section apply for the useful life, expressed in vehicle miles, or hours of engine operation, or years in service, whichever comes first, as follows:

Table 4 to Paragraph (e) of § 1036.104—Useful Life by Primary Intended Service Class

Primary intended service classModel year 2026 and earlierModel year 2027 and later
MilesYearsHoursMilesYearsHours
Spark-ignition HDE110,00010200,0001510,000
Light HDE110,00010270,0001513,000
Medium HDE185,00010350,0001217,000
Heavy HDE435,0001022,000650,0001132,000

(f) Applicability for testing. The emission standards in this subpart apply to all testing, including certification, selective enforcement audits, and in-use testing. For selective enforcement audits, we may require you to perform the appropriate duty-cycle testing as specified in §§ 1036.510, 1036.512, and 1036.514. We may direct you to do additional testing to show that your engines meet the off-cycle standards.

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