§1048.101 What exhaust emission standards must my engines meet?

Apply the exhaust emission standards in this section by model year. You may choose to certify engines earlier than we require. The Tier 1 standards apply only to steady-state testing, as described in paragraph (b) of this section. The Tier 2 standards apply to steady-state, transient, and field testing, as described in paragraphs (a), (b), and (c) of this section.

(a) Standards for transient testing. Starting in the 2007 model year, Tier 2 exhaust emission standards apply for transient measurement of emissions with the duty-cycle test procedures in subpart F of this part:

(1) The Tier 2 HC+NOX standard is 2.7 g/kW-hr and the Tier 2 CO standard is 4.4 g/kW-hr. For severe-duty engines, the Tier 2 HC+NOX standard is 2.7 g/kW-hr and the Tier 2 CO standard is 130.0 g/kW-hr. The standards in this paragraph (a) do not apply for transient testing of high-load engines.

(2) You may optionally certify your engines according to the following formula instead of the standards in paragraph (a)(1) of this section: (HC+NOX) × CO ^0.784 ≤ 8.57. The HC+NOX and CO emission levels you select to satisfy this formula, rounded to the nearest 0.1 g/kW-hr, become the emission standards that apply for those engines. You may not select an HC+NOX emission standard higher than 2.7 g/kW-hr or a CO emission standard higher than 20.6 g/kW-hr. The following table illustrates a range of possible values under this paragraph (a)(2):

    Table 1 of § 1048.101_Examples of Possible Tier 2 Duty-cycle
                           Emission Standards
------------------------------------------------------------------------
                                                              CO  (g/kW-
                HC+NO[INF]X[/INF]  (g/kW-hr)                     hr)
------------------------------------------------------------------------
2.7........................................................          4.4
2.2........................................................          5.6
1.7........................................................          7.9
1.3........................................................         11.1
1.0........................................................         15.5
0.8........................................................         20.6
------------------------------------------------------------------------

(b) Standards for steady-state testing. Except as we allow in paragraph (d) of this section, the following exhaust emission standards apply for steady-state measurement of emissions with the duty-cycle test procedures in subpart F of this part:

(1) The following table shows the Tier 1 exhaust emission standards that apply to engines from 2004 through 2006 model years:

                         Table 2 of § 1048.101_Tier 1 Emission Standards (g/kW-hr)
----------------------------------------------------------------------------------------------------------------
                                                               General emission           Alternate emission
                                                                   standards           standards for severe-duty
                                                         ----------------------------           engines
                         Testing                                                     ---------------------------
                                                          HC+NO[INF]X[/       CO      HC+NO[INF]X[/
                                                               INF]                        INF]           CO
----------------------------------------------------------------------------------------------------------------
Certification and production-line testing...............           4.0          50.0           4.0         130.0
In-use testing..........................................           5.4          50.0           5.4         130.0
----------------------------------------------------------------------------------------------------------------

(2) Starting in the 2007 model year, engines must meet the Tier 2 exhaust emission standards in paragraph (a) of this section for both steady-state and transient testing. See paragraph (d) of this section for alternate standards that apply for certain engines.

(c) Standards for field testing. Starting in 2007, the following Tier 2 exhaust emission standards apply for emission measurements with the field-testing procedures in subpart F of this part:

(1) The HC+NOX standard is 3.8 g/kW-hr and the CO standard is 6.5 g/kW-hr. For severe-duty engines, the HC+NOX standard is 3.8 g/kW-hr and the CO standard is 200.0 g/kW-hr. For natural gas-fueled engines, you are not required to measure nonmethane hydrocarbon emissions or total hydrocarbon emissions for testing to show that the engine meets the emission standards of this paragraph (c); that is, you may assume HC emissions are equal to zero.

(2) You may apply the following formula to determine alternate emission standards that apply to your engines instead of the standards in paragraph (c)(1) of this section: (HC+NOX) × CO ^0.791 ≤ 16.78. HC+NOX emission levels may not exceed 3.8 g/kW-hr and CO emission levels may not exceed 31.0 g/kW-hr. The following table illustrates a range of possible values under this paragraph (c)(2):

  Table 3 of § 1048.101_Examples of Possible Tier 2 Field-testing
                           Emission Standards
------------------------------------------------------------------------
                                                              CO  (g/kW-
                HC+NO[INF]X[/INF]  (g/kW-hr)                     hr)
------------------------------------------------------------------------
3.8........................................................          6.5
3.1........................................................          8.5
2.4........................................................         11.7
1.8........................................................         16.8
1.4........................................................         23.1
1.1........................................................         31.0
------------------------------------------------------------------------

(d) Engine protection. For engines that require enrichment at high loads to protect the engine, you may ask to meet alternate Tier 2 standards of 2.7 g/kW-hr for HC+NOX and 31.0 g/kW-hr for CO instead of the emission standards described in paragraph (b)(2) of this section for steady-state testing. If we approve your request, you must still meet the transient testing standards in paragraph (a) of this section and the field-testing standards in paragraph (c) of this section. To qualify for this allowance, you must do all the following things:

(1) Show that enrichment is necessary to protect the engine from damage.

(2) Show that you limit enrichment to operating modes that require additional cooling to protect the engine from damage.

(3) Show in your application for certification that enrichment will rarely occur in use in the equipment in which your engines are installed. For example, an engine that is expected to operate 5 percent of the time in use with enrichment would clearly not qualify.

(4) Include in your installation instructions any steps necessary for someone installing your engines to prevent enrichment during normal operation (see §1048.130).

(e) Fuel types. Apply the exhaust emission standards in this section for engines using each type of fuel specified in 40 CFR part 1065, subpart C, for which they are designed to operate. You must meet the numerical emission standards for hydrocarbons in this section based on the following types of hydrocarbon emissions for engines powered by the following fuels:

(1) Gasoline- and LPG-fueled engines: THC emissions.

(2) Natural gas-fueled engines: NMHC emissions.

(3) Alcohol-fueled engines: THCE emissions.

(f) Small engines. Certain engines with total displacement at or below 1000 cc may comply with the requirements of 40 CFR part 90 instead of complying with the requirements of this part, as described in §1048.615.

(g) Useful life. Your engines must meet the exhaust emission standards in paragraphs (a) through (c) of this section over their full useful life (§1048.240 describes how to use deterioration factors to show this). The minimum useful life is 5,000 hours of operation or seven years, whichever comes first.

(1) Specify a longer useful life in hours for an engine family under either of two conditions:

(i) If you design, advertise, or market your engine to operate longer than the minimum useful life (your recommended hours until rebuild may indicate a longer design life).

(ii) If your basic mechanical warranty is longer than the minimum useful life.

(2) You may request a shorter useful life for an engine family if you have documentation from in-use engines showing that these engines will rarely operate longer than the alternate useful life. The useful life value may not be shorter than any of the following:

(i) 1,000 hours of operation.

(ii) Your recommended overhaul interval.

(iii) Your mechanical warranty for the engine.

(h) Applicability for testing. The standards in this subpart apply to all testing, including production-line and in-use testing, as described in subparts D and E of this part.