Numerous investigators have reported that with the use of biodiesel as a fuel in diesel engines, a reduction in harmful exhaust emissions and equivalent engine performance with diesel fuel were attained. Di et al. [4] investigated the effect of biodieselediesel blends on the gaseous emission of a direct injection (DI) diesel engine. Experiments were conducted on a 4-cylinder directinjection diesel engine under five engine loads at the maximum torque engine speed of 1800 rpm. Four biodiesel-blended fuels with oxygen concentrations of 2%, 4%, 6% and 8% were used. For the blended fuels, HC and CO emissions decreased while the brake thermal efficiency and the NOx emissions increased.