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Three types of after-treatment for reduction of diesel exhaust particulate are investigated mainly about their characteristics of filtration and regeneration. They are ceramic foam filter (CFF) and microwave regeneration (MR), stainless steel net trap with electrostatic collector (SSNTEC) and reverse jet regeneration (RJR) with high pressure gas, wall flow ceramic filter (WFCF) and infrared heating regeneration (IHR). With the data from experiments, the filtration efficiency of CFF is up to 60% and the efficiency of MWR reach 80% upward. The average efficiency of SSNTEC is about 60% and the efficiency of RJR is just 55%. WFCF and IHR have outstanding performance, the efficiency of WFCF reach 90% upward and its IHR is complete.

A new kind of diesel particulate after-treatment system (EDPF) has been developed. It uses stainless steel nets as the particulate trapping part and uses reverse blowing unit combining with centrifugal collector as the regeneration part. In order to improve the filtering efficiency of stainless steel nets, corona-discharging technology is applied to charge particles before the stainless steel nets. The test result on the 6110 Diesel bench scale shows that the filtering efficiency of the EDPF system can reach to about 70% and the EDPF system is successful.

A kind of fibrous filter made from stainless steel (SS) wire net has been developed by in our institutes. This paper is to study modeling and computing method for the fibrous filters with image effect based on the previous studies. It takes the exhaust aerosol of diesel engine as an even floating flow composed of exhaust and particulate, under the effect of electrical field force, the particulate deviate from other gas phase components and deposit on the fibers. Mathematics models for calculating the flow and the electric field, as well as the capture efficiency are given in this paper. These mathematics models are used for calculating a single fiber model.

A kind of fibrous filter made from stainless steel (SS) wire net with image effects has been developed in our institutes. The filtering medium is composed of stainless steel nets, so there are effects of neighboring fibers on different layer on the particle-capturing efficiency. We have studied the mathematics model for this filter in paper [1]. This paper mainly researches the influence of two neighboring fibers arranged in series through computing and analyzing an inline two-fiber model of the filter. The computed results point that this kind of the fiber arrangement in series is not a good choice for the fiber.

The mathematical model for the microwave regeneration of diesel particulate filter is proposed according to the characteristic of microwave regeneration process. The model is used to calculate the temperature field, distribution of particulate and density field of oxygen in the filter during the process of regeneration with typical ceramic foam particulate fitter data. The parametric study demonstrates how some of the main parameters, such as microwave attenuation constant of the filter, filter particulate loading, the power and distribution of microwave energy and so on, affect the efficiency of regeneration, the maximum filter temperature and regeneration duration. The results show that it is possible to regenerate the diesel particulate filters in certain conditions by using microwave energy.