Modern tools for diesel engine combustion investigation

This paper describes the operating principle and the current development status of high-speed direct-injection diesel engines used in passenger cars. This type of engine has an advantage in efficiency of the order of 30% compared with current gasoline engines with three-way catalyst and has a high potential for further improvement, such as reduction of NO and soot emissions. The present state of knowledge of diesel engine combustion has benefited from optical diagnostic techniques that permit deeper insights into the in-cylinder processes such as flow generation, fuel injection and spray formation, atomization and mixing, autoignition and combustion, and the formation and reduction of pullutants. Part of the work described was carried out within the European (diesel) engine research programs IDEA and IDEA EFFECT. Finally, a summary is given of future trends in combustion diagnostics and engine developments, with emphasis on the significance of the D1 diesel engine as a power plant for passenger cars both inside and outside of Europe.