An on-line particle trapping test was carried out with a diesel particulate filter(DPF). The trapping characteristics of the DPF for different particle size were analyzed by using an exhaust particle size spectrometer. The stacking morphology and oxidation characteristics of the particles at the front and rear ends of the DPF were investigated by scanning electron microscope and thermo gravimetric analyzer. Results show that the DPF captures large size particles better than small size particles

and can almost completely intercept accumulation mode particles. Since the soot on the filter wall reduces the filter pore size

the trapping efficiency of the DPF increases with the rise of sampling time

with only a small amount of nucleation mode particles leaked off. Use of the DPF can lead to an increase in the content of volatile components coupled to the reduction of elemental carbon content

and eventually promotes the enhanced oxidation activity downstream of its outlet.