Investigating the Performance and Pollutants of a Light Agricultural SI Engine with Gasoline-ethanol Fuel under Low Load Conditions and Constant Equivalence Ratio

Bioethanol-gasoline blends are used to reduce fossil-fuel consumption in SI engines (SIE). In this experimental study the effect of different blends of gasoline- bioethanol on the performance and emissions of a carbureted, single-cylinder, and four-stroke SIE is investigated at low load. Tests were performed at various speeds and the constant equivalence ratio. The results showed that ηth,b decreased with the increase of ethanol percentage, and the latent heat of evaporation increased with the increase of ethanol blend percentage. Considering that the constant equivalence ratio, increasing the percentage of ethanol caused a decrease in the intake air mass and volumetric efficiency and simultaneously reducing the volume efficiency and increasing the latent heat caused a decrease of the air-fuel mixture temperature, misfiring, and resulted in the flame being extinguished. Tout and Tbody dropped up to ۸.۳۷% and ۱۲.۶۳%, respectively. The emission of NOX also decreased up to ۹۳.۷۳%. Of course, UHC will increase up to ۱۶۰%. The emission of CO and CO۲ increased by ۹۲.۵% and decreased by ۲۳.۹۸%, respectively. In conclusion, addition of ethanol to gasoline causes a decrease in ηth,b and a significant decrease in the emission of NOX and CO۲ pollutants; however, it will increase UHC and CO emissions.

کلیدواژه ها:

Bioethanol ، low load ، constant equivalence ratio ، Thermal efficiency ، brake-specific fuel consumption