Abstract:Biodiesel fuel blends were used on a diesel car, and the effects of biodiesel on vehicle’s particle number and size emission characters were studied with an engine exhaust particle sizer (EEPS) at new European driving cycle (NEDC) test. A test was made without any engine modification on a pure petroleum diesel and a pure biodiesel as well as some blends of petroleum diesel biodiesel with the blend ratio of 5%, 10%, 20% or 50% respectively. The results show that the total concentration of particle number reduces little when the car is fueled with biodiesel. The number of accumulation mode particles decreases whereas the number of nucleation mode particles increases significantly with the increasing of the blend ratio of biodiesel. At the same time, the average diameter of particle matters decreases and the peak of particle number concentration shifts to small diameter particle side.