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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.

In order to improve the predicting capability of KIVA-3V code for a diesel engine, various numerical models were reviewed. From the comparison of TAB, wave and χ - square distribution models for atomization of a liquid fuel jet, it was found that the wave model was most suitable for predicting a diesel spray because of proper breakup length. The high pressure evaporation model, which considered the air in a combustion chamber as a real gas, predicted earlier ignition about 0.7 °CA than the low pressure model. For the diesel ignition, the Hardenberg model predicted shorter ignition delay than the Shell model and measurements, and the Hardenberg model showed the spatially uniform ignition. For soot emission, the phenomenological models suggested by Foster, Belardini and Hiroyasu were studied. The Hiroyasu model could be used effectively for the prediction of soot emission although it did not provide detailed information on soot formation.

Diesel engine is being used widely in many industrial fields, as it provides merits in the aspects of higher thermal efficiency and less CO₂ emission. However, NOx regulations for diesel engines are being strengthened and it is impossible to meet the emission standard without aftertreatment systems such as SCR (Selective catalytic reduction), LNC (Lean NOx catalyst), and LNT (Lean NOx trap). Among the NOx reduction aftertreatments, Urea-SCR system is known as the most stable and efficient method to solve the problem of NOx emission. But this device has some issues associated with the ammonia slip phenomenon which is occurred by shortage of evaporation and thermolysis time, and that makes it difficult to achieve uniform distribution of the injected urea.

Nowadays, automobile manufacturers are focusing on reducing exhaust-gas emissions because of their harmful effects on humans and the environment, such as global warming due to greenhouse gases. Direct injection combustion is a promising technology that can significantly improve fuel economy compared to conventional port fuel injection spark ignition engines. However, previous studies indicate that relatively high levels of nitrogen oxide (NOx) emission were produced with gasoline fuel in a spray-guided-type combustion system as a result of the stratified combustion characteristics. Because a lean-burn engine cannot employ a three-way catalyst, NOx emissions can be an obstacle to commercializing a lean-burn direct injection engine. Liquefied petroleum gas (LPG) fuel was proposed as an alternative for reducing NOx emission because it has a higher vapor pressure than gasoline and decreases the local rich mixture region as a result of an improved mixing process.

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.

One of most effective NOx control technology of modern diesel engines is SCR with ammonia. Current NOx reduction systems are designed to use a solution of urea dissolved in water as a source of ammonia. However, the liquid urea systems have technical difficulties, such as a freezing point below −11°C and solid deposit formation in the exhaust temperature below 200°C. The objective of this study is to investigate the possibility of a new ammonia generation system that uses low-cost solid ammonium salt, such as solid urea and ammonium carbonate. The result shows that ammonium carbonate is more suitable than solid urea because of low decomposition temperature and no change to the other ammonium salt during the decomposition process. This paper also shows the NOx reduction capability of the new ammonia delivery system that uses ammonium carbonate.