Comparative investigation of the effects of lower and higher alcohols/bio-diesel blends on engine performance and emissions characteristics of a diesel engine

ABSTRACT

The use of lower alcohol (such as methanol and ethanol) blends in diesel engines shows problems like phase separation, miscibility, higher NO_x emissions etc. The addition of higher alcohols with either diesel or biodiesel is relatively new and only a little information is available on the effects of higher alcohols. In this work, the engine performance and emissions characteristics were compared between the lower and higher alcohol blended with biodiesel. Conventional diesel and biodiesel are considered as the reference fuels. Three lower alcohols (methanol, ethanol and propanol) and three higher alcohols (butanol, pentanol and octanol) of each 50% by volume were mixed with biodiesel of 50% by volume. Experiments were conducted on a single cylinder compression ignition diesel engine by varying the load conditions at a constant speed. Engine performance and emissions of CO, CO₂, NO_x and HC were determined. The results are discussed.