Study on the PM2.5 and Ultra Fine PM Characteristics of Diesel Vehicle with DPF Under the Different Driving Conditions

Abstract

Diesel particulate filter (DPF) can drastically reduce the mass of diesel PM (Particulate Matter) emission, as well as, it can significantly reduce the concentration of fine particulate, such as PM2.5. In order to study the PM2.5 characteristics and the effect of driving conditions to the DPF filter efficiencies, the suitable filters were installed on the vehicles without any matching and calibration. Under NEDC, PM emission of upstream and downstream of DPF on five commercial diesel vehicles was tested by CVS, and the number concentration and mass concentration of PM was tested by ELPI. The results showed that DPF filter efficiencies can over 92 % for both PM10 and PM2.5 under most operating conditions. However, under a fewer operating modes, such as a 200s period after cold start, and a 50s period before the end of NEDC which is a rapid slowdown period, the efficiencies of DPF filter is low. This paper reports a work on study for the PM2.5 and ultra fine PM characteristics of diesel vehicle with DPF under the different driving conditions, these impact factors for DPF filter efficiency with some conditions, by comparing both of number concentration and mass concentration on the PM size distribution before and after DPF. This paper reports the emission characteristics of PM2.5 and ultra-fine particles before and after DPF filter under different driving conditions. The results show that DPF filter can reduce PM emission significantly, but attention to the control of DPF filter is needed under the rapid slowdown condition.