Abstract: A test bench for D30TCI diesel engine with DOC+DPF is built to conduct the pressure drop characteristics test on the carriers with two different structures. The calculation model for diesel particulate filter (DPF) is established, the effects of ash distribution coefficient on the pressure drop and trap characteristics of DPF are studied, and the inlet/outlet aperture ratio of the carrier with asymmetric hole structure is optimized. The discrete phase model is used to simulate the effects of ash deposition and carrier structure on the gas flow movement in DPF channel and particulate deposition characteristics. The results show that the DPF pressure drop and trapping efficiency increase with the increase of ash distribution coefficient, and there is an optimal range (1.25~1.35) for the inlet/outlet aperture ratio of the carrier with asymmetric hole structure to achieve the optimal DPF pressure drop and trap characteristics. Along the axial direction of DPF, the gas flow velocity in inlet channel rises first and then falls, while that in outlet channel gradually increases. The inlet/outlet velocities of DPF with asymmetric hole structure are higher than that with symmetric hole structure. Ash accumulation may aggravate the change of velocity in DPF channel, which reaches the highest in the center while lowers in the vicinity of wall surface. The particulates in DPF channels exhibit an uneven distribution: more in the front-end and less in the rear-end. Compared with asymmetric hole structure, the DPF with symmetric hole structure traps less particulates with more uneven distribution in particulate concentration, but ash accumulation can enhance the evenness of particulate distribution

Key words: diesel particulate filter, asymmetric hole structure, ash, pressure drop, flow field