Emission Standards Reference Guide
Heavy-Duty Highway Compression-Ignition Engines And Urban Buses -- Exhaust Emission Standards
| Year | HC(g/ bhp-hr) |
NMH C (g/ bhp-hr) |
NMHC + NOx g/ bhp-hr) |
NOx (g/ bhp-hr) |
PM (g/ bhp-hr) |
CO (gbhp-hr) | Idle CO (percent exhaust gas flow) | Smokea (Per- centage) |
Useful Life (hours/ years/ miles) |
Warranty Period (years/ miles) |
|
|---|---|---|---|---|---|---|---|---|---|---|---|
| Federalb | 1974-78 | - | - | 16 | - | - | 40 | - | 20 / 15 / 50 | - | - |
| 1979-84 | 1.5 | - | 10 | - | - | 25 | - | 20 / 15 / 50 | - | - | |
| 1985-87 | 1.3 | - | - | 10.7 | - | 15.5 | - | 20 / 15 / 50 | LHDDE: - / 8 / 110,000 MHDDE: - / 8 / 185,000 HHDDE: - / 8 / 290,000 |
- | |
| 1988-89 | 1.3d | - | - | 10.7 | 0.6 | 15.5 | 0.5c | 20 / 15 / 50 |
1990-97 and 1998+ for HC, CO, and PM: LHDDE: - / 8 / 110,000 MHDDE: - / 8 / 185,000 HHDDE: - / 8 / 290,000 1994+ urban buses for PM only: - / 10 / 290,000 1998+ for NOx: LHDDE: - / 10 / 110,000 MHDDE: - / 10 / 185,000 HHDDE: - / 10 / 290,000 |
5 / 100,000 q | |
| 1990 | 1.3d | - | - | 6.0 | 0.6 | 15.5 | 0.5c | 20 / 15 / 50 | |||
| 1991-93 | 1.3 | - | - | 5.0 [ABT] | 0.25 [ABT] 0.10e |
15.5 | 0.5c | 20 / 15 / 50 | |||
| 1994-97 | 1.3 | - | - | 5.0 [ABT] | 0.1 [ABT] 0.07f, 0.05g |
15.5 | 0.5c | 20 / 15 / 50 | |||
| 1998-2003 | 1.3 | - | - | 4.0 [ABT] | 0.1 [ABT] 0.05g |
15.5 | 0.5c | 20 / 15 / 50 | |||
| 2004-2006h | - | - | 2.4 (or 2.5 with a limit of 0.5 on NMHC)o [ABTi,j] | - | 0.1 0.05g |
15.5 | 0.5 | 20 / 15 / 50 | For all pollutants: p LHDDE: - / 10 / 110,000 MHDDE: - / 10 / 185,000 HHDDE: 22,000 / 10 / 435,000 |
LHDDE: 5 / 50,000 All other HDDE: 5 / 100,000 q |
|
| 2007+h,k,l,m,n | - | 0.14o | 2.4 (or 2.5 with a limit of 0.5 on NMHC) [ABT] | 0.2o | 0.01 | 15.5 | 0.5 | 20 / 15 / 50 |
Notes:
The test procedures are the EPA Transient Test Procedure and the EPA Smoke Test Procedure.
a Percentages apply to smoke opacity at acceleration/lug/peak modes.
b Standards for 1990 apply only to diesel-fueled heavy-duty engines (HDE). Standards for 1991+ apply to both diesel- and methanol-fueled HDEs. Standards that apply to urban buses specifically are footnoted.
c This standard applies to the following fueled engines for the following model years: methanol - 1990+, natural gas and liquefied petroleum gas (LPG) - 1994+.
d For petroleum-fueled engines, the standard is for hydrocarbons (HC). For methanol-fueled engines, the standard is for total hydrocarbon equivalent (THCE).
e Certification standard for urban buses for 1993.
f Certification standard for urban buses from 1994-95.
g Certification standard for urban buses from 1996 and later. The in-use standard is 0.07.
h Load Response Test certification data submittal requirements take effect for heavy-duty diesel engines beginning in model year 2004. The following requirements take effect with the 2007 model year: steady-state test requirement and Not-to-Exceed (NTE) test procedures for testing of in-use engines. On-board diagnostic requirements applicable to heavy-duty diesel vehicles and engines up to 14,000 pounds gross vehicle weight rating (GVWR) phase in from the 2005 through 2007 model years.
i The modified averaging, banking, and trading program for 1998 and later model year engines applies only to diesel cycle engines. Credits generated under the modified program may be used only in 2004 and later model years.
j For heavy-duty diesel engines, there are three options to the measurement procedures currently in place for alternative fueled engines: (1) use a THC measurement in place of an non-methane hydrocarbon (NMHC) measurement; (2) use a measurement procedure specified by the manufacturer with prior approval of the Administrator; or (3) subtract two percent from the measured THC value to obtain an NMHC value. The methodology must be specified at time of certification and will remain the same for the engine family throughout the engines' useful life. For natural gas vehicles, EPA allows the option of measuring NMHC through direct quantification of individual species by gas chromatography.
k Starting in 2006, refiners must begin producing highway diesel fuel that meets a maximum sulfur standard of 15 parts per million (ppm).
l Subject to a Supplemental Emission Test (1.0 x Federal Test Procedure [FTP] standard (or Family Emission Limit [FEL]) for nitrogen oxides [NOx], NMHC, and particulate matter [PM]) and a NTE test (1.5 x FTP standard [or FEL] for NOx, NMHC, and PM).
m EPA adopted the lab-testing and field-testing specifications in 40 CFR Part 1065 for heavy-duty highway engines, including both diesel and Otto-cycle engines. These procedures replace those previously published in 40 Code of Federal Regulations (CFR) Part 86, Subpart N. Any new testing for 2010 and later model years must be done using the 40 CFR Part 1065 procedures.
n Two-phase in-use NTE testing program for heavy-duty diesel vehicles. The program begins with the 2007 model year for gaseous pollutants and 2008 for PM. The requirements apply to diesel engines certified for use in heavy-duty vehicles (including buses) with GVWRs greater than 8,500 pounds. However, the requirements do not apply to any heavy-duty diesel vehicle that was certified using a chassis dynamometer, including medium-duty passenger vehicles with GVWRs of between 8,500 and 10,000 pounds.
o NOx and NMHC standards will be phased in together between 2007 and 2010. The phase-in will be on a percent-of-sales basis: 50 percent from 2007 to 2009 and 100 percent in 2010.
p Note that for an individual engine, if the useful life hours interval is reached before the engine reaches 10 years or 100,000 miles, the useful life shall become 10 years or 100,000 miles, whichever occurs first, as required under Clean Air Act section 202(d).
q Years or miles, whichever comes first but never less than the basic mechanical warranty for the engine family.
Code of Federal Regulations (CFR) Citations:
- 40 CFR 86.099-11 Emission standards for 1999 and later model year diesel heavy-duty engines and vehicles.
- 40 CFR 86.004-11 Emission standards for 2004 and later model year diesel heavy-duty engines and vehicles.
- 40 CFR 86.007-11 Emission standards and supplemental requirements for 2007 and later model year diesel heavy-duty engines and vehicles.