requirements are equivalent to 0.34 to 0.61 g/bhp-hr.
b Engineering estimate.
Table 4-4: Off-Road Equipment Emissions
2010 CA Diesel
Energy rate (Btu/bhp-hr)
a 20 percent increase in energy consumption with gasoline.
b 20 percent reduction in mass emissions with RFG.
Sources: Kreebe 1992, A. D. Little.
Based on a population profile of reciprocating engines prime movers (Huey 1993) and emissions data for individual makes and models of engines (Urban 1980 and Fanick 1988), the energy consumption for engines is estimated to be 8,000 Btu/bhp-hr. This value can range from 6,000 to 10,000 Btu/bhp-hr.
Population profiles of reciprocating engine prime movers indicate that, the majority of these engines are lean-burn with relatively few being stoichiometric or rich-burn engines. The emission factors assigned to reciprocating engine prime movers are associated with lean-burn engines. Uncontrolled lean burn engines do not operate sufficiently lean to provide significant NOx reductions. All new lean burn engines sold in North America are configured for low NOx emissions.
NOx emissions outside the SoCAB (CA and the U.S.) are estimated to be 6 g/bhp-hr, which is based on an engine prime mover population and emissions profile. NOx emissions for an uncontrolled lean-burn prime mover range from 10 to 12 g/bhp-hr, whereas the emissions for a controlled lean-burn prime mover are about 1 to 2 g/bhp-hr (Huey 1994). This study assumes that roughly half of the engine prime movers outside the SoCAB are controlled.