Imaging in Transport Processes

ISBN Print: 978-1-56700-382-6

FLAME CHARACTERISTICS IN A SMALL DI DIESEL ENGINE EQUIPPED WITH TRANSPARENT PISTON

Resumo

The small high-speed DI diesel engine has been applied in a wide range of fields in recent years, owing to its high thermal efficiency and its low fuel consumption. However, many kinds of exhaust emissions, such as NOx, dry soot, SOF and unburnt hydrocarbons are discharged from this type of engine. Therefore, it is strongly desired by researchers and engineers to clarify the mechanism for the generation of these exhaust emissions, and to reduce them, in order to meet very severe future regulations for the preservation of the earth's environment. Combustion processes in diesel engines are very complex phenomena. Namely, the processes consist of the injection of fuel oil, the formation of spray, the vaporization of droplets, the mixing of their vapor with the surrounding air, the formation of combustible mixture, the ignition and the burning. In addition, all of these phenomena overlap each other, and exhaust emissions are generated during the progress of the processes. Consequently, the reduction of the exhaust emissions as well as the improvement of the engine performance makes it necessary to obtain basic information such as profiles of fuel vapor concentration, flame temperature, soot concentration and chemical species concentration on the combustion phenomena.