Technical Paper
The Effect of High Ethanol Blends on Emissions from Small Utility Engines
1999-09-28
1999-01-3345
Emissions of total hydrocarbons, carbon monoxide, nitrogen oxides, and combined hydrocarbons and nitrogen oxides from small utility engines were used to judge the effect of ethanol addition (zero to 50%vol) to a hydrocarbon fuel with factory air-fuel ratio carburetor settings. In this study, emissions from two 4-stroke 9.3 kW (12.5 hp) side-valve engines and one 4-stroke 9.3 kW (12.5 hp) overhead valve engine were assessed to support conclusions. Emissions differences due to the differing valve orientations were addressed as a secondary objective. A series of RBOB plus ethanol (EtOH) fuel blends were used in this parametric study. RBOB is the base fuel in which oxygenates are blended to produce reformulated gasoline (RFG) for use in Clean Air Act Amendments-designated Ozone Non-attainment Areas. RBOB+EtOH fuel blend (an oxygenated fuel) emissions were compared to RBOB (a nonoxygenated fuel) emissions to assess the effect of ethanol addition on emissions.
