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Exhaust gases of diesel vehicles are considered as a major reason of city air pollutions. The DOC(Diesel Oxidation Catalyst) and DPF(Diesel Particulate Filter) have been used to reduce the emissions of diesel vehicles. The DOC can oxides HC, CO and SOF(Soluble Organic Fraction) in the PM emissions, and the DPFs can filter the most of solid PM, such as carbon particles. As the DPFs, wall flow type ceramic honeycomb filters have been commonly used and now being still advanced. However, the cost and durability of the currently used DPFs are not perfect yet. Metal foam is the one of promising materials for the DPFs due to its cost effectiveness, good thermal conductivity and high mechanical strength. The metal foam can be produced with various pore sizes and strut thickness and finally can be coated with catalytic wash-coats with low cost.

Filtration studies about the metal foam filters combined with electrostatic precipitation, which can be used as a new DPF device, have been performed. Filtration efficiency of the metal foam filter is significantly low because most particles are penetrated through the large filter-pores. However the efficiency was considerably improved by forming a high electric field on the filter surface. The pressure drop was not significantly increased by the particle deposition because the particles do not completely clog the filter pores.

A Diesel Particulate Filter (DPF) is an effective technology for reducing Particulate Matter (PM) emitted from diesel engines. In modern light duty diesel engines, DPF is regenerated by the post-fuel-injection method. In this method, the fuel is injected into the combustion chamber during the expansion stroke to produce heat to burn out the PM trapped in the DPF. However, this method also causes several problems, such as complicated engine torque control and oil dilution by fuel. In this study, a rotating plasma burner was developed for DPF regeneration as an alternative to the postfuel-injection method. Since it is important to reduce the electric energy consumption for plasma generation, which is directly related with electric noise and system cost, several design factors, such as the boosting voltage of transformers, electrode gaps, and plasma frequency were evaluated. A transformer with a low boosting voltage is desirable to ensure low electric noise.

A flow model is a convenient tool for developing the engine intake system. Two flow models for the branched engine intake were developed by the finite difference method and the method of characteristics. The results from the models were compared with the experimental data and the appropriate boundary conditions were established for each model. Modeling the flow at the intake and exhaust valves with a cylinder and at the pipe branches were the most critical part of the flow models affecting the accuracy of the solutions. From two models, it was found that the finite difference model was simpler than the characteristic model in formulation with the better accuracy. The effects of valve timings and intake geometry were studied by the flow models to design the optimum intake system.