|
Tier Ratings
EPA emission standards for NOx, hydrocarbons (HC), and PM from new
nonroad diesel engines >50 horsepower include a 3-tiered progression to
low emission standards. Each tier involves a phase-in (by horsepower rating)
over several years. The Tier 1 standards were phased in for different engine
sizes between 1996 and 2005, reducing NOx emissions from these engines by 30
percent. The more stringent "Tier 2" emission standards include engines from
2001 to 2008 and the most stringent "Tier 3" standards apply to engines
between 50 and 750 hp from 2006 to 2011.
Tier
0 |
Tier
1 |
Tier
2 |
Tier
3 |
Model Year |
|
Horsepower |
1996 |
1997 |
1998 |
1999 |
2000 |
2001 |
2002 |
2003 |
2004 |
2005 |
2006 |
2007 |
2008 |
| >50
< 100 bhp |
0 |
0 |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
2 |
2 |
2 |
3 |
| >100
< 175 bhp |
0 |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
2 |
2 |
2 |
3 |
3 |
| >175
< 300 bhp |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
2 |
2 |
3 |
3 |
3 |
| >300
< 600 bhp |
1 |
1 |
1 |
1 |
1 |
2 |
2 |
2 |
2 |
2 |
3 |
3 |
3 |
| >600
< 750 bhp |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
2 |
2 |
2 |
3 |
3 |
3 |
| >
750 bhp |
0 |
0 |
0 |
0 |
1 |
1 |
1 |
1 |
1 |
1 |
2 |
2 |
2 |
|
