Spray Cpmbustlon Study for Super Low NOx Emission

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Diesel combuston processes are significantly affected by the fuel-air mixing process, that is one of the most effective measure for reducing exhaust gas emissions is controling the fuel-air mixing process in the combustion chamber. Especially, controling spatial and temporal distributions of fuel-air mixture is considered to be the key technology for future diesel engines. Therefore, the effects of the spatial and temporal distributions of the fuel-air mixture on diesel combustion and exhaust processes were examined by using a computer simulaiton, a constant volume combustion chamber and an experimental engine equipped with multi-injectors. The results of the current study are summarized as follows :1. A calculative investigation was performed in order to examine the effects of temporal and spatial arrangement of fuel sprays on exhaust emission using a phenomenological spray combustion model. As a result of the calculations, effective measures were found for simultaneous reduction of N … More Ox and smoke emissions.2. Behaviors and characteristics of the diesel spray with split-injection were studied by using an electrically controlled common rail injection system and a high pressure and temperature bomb. One of the sprays were injected from a multi-hole nozzle into a 2-dimensional model combustion chamber installed in the high pressure and high temperature bomb. The spray was observed by schlieren photography, focused-shadow photography and a high speed video camera. Air-fuel formation and characteristics of the spray with split-injectionwas clarified.3. Characteristics of combustion and exhaust emission of D.I.Diesel Engine were investigated under various spatial arrangement of fuel sprays. A cylinder liner was elongated and a flat-top piston was installed in the engine in order to obtain a respectively large pancake-type combustion chamber. Such modification the engine made it possible to obtain radial arrangement of six to ten spravs in the combustion chamber. Effects of spatial distribution of fuel sprays on diesel combustion and exhaust emissions were clarified.All these things made it clear that the guides for developing low NOx and smoke emission engines were obtained. Less