(a) The Tier 1 standards of paragraph (a)(1) of this section apply until replaced by the standards of paragraph (a)(2) of this section.

(1) Tier 1 standards. NOX emissions from model year 2004 and later engines with displacement of 2.5 or more liters per cylinder may not exceed the following values:

(i) 17.0 g/kW-hr when maximum test speed is less than 130 rpm.

(ii) 45.0 × N−0.20 when maximum test speed is at least 130 but less than 2000 rpm, where N is the maximum test speed of the engine in revolutions per minute.

(iii) 9.8 g/kW-hr when maximum test speed is 2000 rpm or more.

(2) Tier 2 standards.

(i) Exhaust emissions from marine compression-ignition engines shall not exceed the applicable Tier 2 exhaust emission standards contained in Table A-1 as follows:

(ii) EPA has not finalized Tier 2 standards for Category 3 engines. EPA will promulgate final Tier 2 standards for Category 3 engines on or before December 17, 2009.

(b) Exhaust emissions of oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter (and other compounds, as applicable) shall be measured using the procedures set forth in subpart B of this part.

(c) In lieu of the THC + NOX standards, and PM standards specified in paragraph (a) of this section, manufacturers may elect to include engine families in the averaging, banking, and trading program, the provisions of which are specified in subpart D of this part. The manufacturer shall then set a family emission limit (FEL) which will serve as the standard for that engine family. The ABT provisions of subpart D of this part do not apply for Category 3 engines.

(d)

(1) Naturally aspirated engines subject to the standards of this section shall not discharge crankcase emissions into the ambient atmosphere.

(2) For engines using turbochargers, pumps, blowers, or superchargers for air induction, if the engine discharges crankcase emissions into the ambient atmosphere in use, these crankcase emissions shall be included in all exhaust emission measurements. This requirement applies only for engines subject to hydrocarbon standards (e.g., THC standards, NMHC standards, or THC + NOX standards).

(3) The crankcase requirements of this paragraph (d) do not apply for Tier 1 engines.

(e) Exhaust emissions from Category 1 and Category 2 propulsion engines subject to the standards (or FELs) in paragraph (a), (c), or (f) of this section shall not exceed:

(1) Commercial marine engines.

(i) 1.20 times the applicable standards (or FELs) when tested in accordance with the supplemental test procedures specified in §94.106 at loads greater than or equal to 45 percent of the maximum power at rated speed or 1.50 times the applicable standards (or FELs) at loads less than 45 percent of the maximum power at rated speed.

(ii) As an option, the manufacturer may choose to comply with limits of 1.25 times the applicable standards (or FELs) when tested over the whole power range in accordance with the supplemental test procedures specified in §94.106, instead of the limits in paragraph (e)(1)(i) of this section.

(2) Recreational marine engines.

(i) 1.20 times the applicable standards (or FELs) when tested in accordance with the supplemental test procedures specified in §94.106 at loads greater than or equal to 45 percent of the maximum power at rated speed and speeds less than 95 percent of maximum test speed, or 1.50 times the applicable standards (or FELs) at loads less than 45 percent of the maximum power at rated speed, or 1.50 times the applicable standards (or FELs) at any loads for speeds greater than or equal to 95 percent of the maximum test speed.

(ii) As an option, the manufacturer may choose to comply with limits of 1.25 times the applicable standards (or FELs) when tested over the whole power range in accordance with the supplemental test procedures specified in §94.106, instead of the limits in paragraph (e)(2)(i) of this section.

(f) The following define the requirements for low-emitting Blue Sky Series engines:

(1) Voluntary standards.

(i) Category 1 and Category 2 engines may be designated “Blue Sky Series” engines by meeting the voluntary standards listed in Table A-2, which apply to all certification and in-use testing:

(ii) Category 3 engines may be designated “Blue Sky Series” engines by meeting these voluntary standards that would apply to all certification and in-use testing:

(A) A NOX standard of 9.0 × N−0.20 where N = the maximum test speed of the engine in revolutions per minute (or 4.8 g/kW-hr for engines with maximum test speeds less than 130 rpm). (Note: Round speed-dependent standards to the nearest 0.1 g/kW-hr.)

(B) An HC standard of 0.4 g/kW-hr.

(C) A CO standard of 3.0 g/kW-hr.

(2) Additional standards. Blue Sky Series engines are subject to all provisions that would otherwise apply under this part.

(3) Test procedures. Manufacturers may use an alternate procedure to demonstrate the desired level of emission control if approved in advance by the Administrator.

(g) Standards for alternative fuels. The standards described in this section apply to compression-ignition engines, irrespective of fuel, with the following two exceptions for Category 1 and Category 2 engines:

(1) Engines fueled with natural gas shall comply with NMHC + NOX standards that are numerically equivalent to the THC + NOX described in paragraph (a) of this section; and

(2) Engines fueled with alcohol fuel shall comply with THCE + NOX standards that are numerically equivalent to the THC + NOX described in paragraph (a) of this section.

[64 FR 73331, Dec. 29, 1999, as amended at 67 FR 68342, Nov. 8, 2002; 68 FR 9782, Feb. 28, 2003; 68 FR 54960, Sept. 19, 2003; 72 FR 68525, Dec. 5, 2007]