Numerical study on the regeneration characteristics of catalytic diesel particulate filter based on real driving emissions in plateau environment

Abstract

In order to study the regeneration characteristics by O2 and NO2 of CDPF (Catalytic diesel particulate filter) at different altitudes, the atmospheric environmental parameters and exhaust emissions under the real driving condition were measured on a pickup truck equipped with the AVL M.O.V.E. PEMS (Portable Emission Measurement System) at average altitudes of 0 km, 2 km, 4 km, respectively. Then a finite rate regeneration reaction model was established. The numerical results show that the regeneration balance cannot be achieved in plateau environment based on the original emission. Through the single factor method, the effects of the exhaust temperature, the mass ratio of the NOx to PM, the oxygen concentration and the ratio of the engine displacement to the filter volume on the soot oxidation rate were simulated. The results show that in order to achieve regeneration balance, the exhaust temperature should be higher than 510 °C or the mass ratio of the NOx to PM should be greater than 70 at an altitude of 2 km, while the mass ratio of the NOx to PM should be greater than 98 at an altitude of 4 km. However, regeneration balance cannot be achieved by changing other single factors. Furthermore, through the orthogonal experimental design, it is found that the exhaust temperature and mass ratio of the NOx to PM are the dominant factors affecting the O2-NO2 regeneration in plateau environment. The maps of the exhaust temperature coupled with the mass ratio of the NOx to PM on soot oxidation rate by O2-NO2 were drawn, which provide a theoretical basis for the regeneration and allocation of the diesel particulate filter in plateau environment.