This study evaluates the use of biodiesel as an alternative fuel for diesel engines. The fuel properties, performance, emission characteristics and combustion characteristics of a four-stroke, four-cylinder water cooled, direct injection (DI) diesel engine operated on biodiesel, 20% biodiesel,30% biodiesel and 50% biodiesel blended fuels were measured. Results related to the direct use of biodiesel as a diesel engine fuel indicate that this is possible but not preferable because of its high viscosity and cetane number. Biodiesel could be used in the blends with diesel fuel, because most of...