Performance and Emissions of a Diesel Engine Fueled by Biodiesel Derived from Different Vegetable Oils and the Characteristics of Combustion of Single Droplets

This paper investigates the performance, combustion characteristics, and emissions of a small single cylinder DI diesel engine with biodiesel fuel (BDF) derived from unused rape, soybean, and palm oils. Compared with ordinary gas oil, the BDFs showed similar brake thermal efficiencies, better ignitability, and considerably reduced smoke densities, while the NO_x emissions were somewhat higher. The injection characteristics and engine performance were also examined using neat Methyl Oleate (OME) and OME-Methyl Palmitate (PME) blends. Basic experiments of suspended single droplets were performed to evaluate the differences in ignition, combustion, and soot formation characteristics of these fuels. The results showed shorter ignition lags and combustion durations for the OME droplets blended with PME and the soot formation rate with OME is about 13% that of gas oil droplets.