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Exhaust gas from the diesel engine contains particulate matter (PM) of soot that affects human health and the environment. For the reduction of the emission of the PM, the diesel particulate filter (DPF) is placed in the exhaust system. The pressure drops increases with the PM deposit quantity in the DPF, which results in the burden of the engine. Therefore, the PM should be removed regularly by oxidation process called regeneration. Consumption of fuel is improved by optimizing the timing of regeneration. However, it is difficult to visualize the behavior of PM trapping and oxidation. We have proposed a series of models from PM deposition to the oxidation process in the DPF. In this study, the behavior of deposition and oxidation of PM in the DPF with a catalyst are calculated. The numerical calculations are performed to estimate PM deposition-oxidation process within the DPF. The results are obtained using the simplified model constructed in this study.

The diesel particulate filter (DPF) has attracted strong attention as a desirable after-treatment device for the particulate matter (PM) contained in exhaust gas of diesel engine. When particulate matter was deposited on a DPF, the pressure drop increases due to the PM trapping in the surface cavities of the DPF. After that, an active regeneration is required. Since more fuel is required for the regeneration in addition to the normal driving (passive regeneration), the fuel economy deteriorates. In order to improve the performance, a passive regeneration is necessary. In this study, we compared the dependence of the shape and depth of the cavity of the DPF on the PM trapping process by a comprehensive overall model and numerical calculation. We found that the pressure drop and elapsed time of the PM trapping varied, strongly depending on the cavity shape of the DPF surface. Further we examined the relative importance of the amount of PM deposit and the surface cavity shape of the DPF.