California Adopts Emission Standards for Large Off Road SI Engines
On October 22, 1998, California's ARB established emission standards for off-road spark-ingnition engines
over 25 hp. The standards will result in three-way catalyst systems being installed on engines
one liter or greater. Off-road engines under one liter will be required to meet the same emission
levels that ARB adopted earlier this year for four-stroke off-road engines under 25 hp used in
lawn and garden equipment. The latter standards are not catalyst-forcing. The standards and
effective dates are shown in Table 1 below.
Table 1
California Exhaust Emission Standards for Large Off-Road SI Engines
(grams per brake horsepower-hour)
|
| Model Year |
Engine
Displacement |
Durability Period
(hours) |
Hydrocarbon plus
Oxides of Nitrogen |
Carbon Monoxide |
| 2002 and
Subsequent |
<1.0 liter |
1000 |
9.0 |
410 |
| 2001 through
2003 |
1.0 liter or
greater |
N/A |
3.0 |
37.0 |
| 2004 through
2006 |
1.0 liter or
greater |
Zero Hours and
3500 hours (as
shown by
deterioration
factor) |
3.01 |
37.01 |
| 2007 and
Subsequent |
1.0 liter or
greater |
5000 hours or 7
years |
3.0 |
37.0 |
| 1. For 2004 through 2006 model-year engine families, in-use compliance standards shall be 4.0 g/bhp-hr
Hydrocarbon plus Oxides of Nitrogen and 50 g/bhp-hr Carbon Monoxide for a durability period of 5000 hours or
7 years. |
[October 27, 1998]
