Search Results

During the recent years, extensive research is conducted worldwide for the purpose of tailpipe emission reduction from diesel engines. These efforts resulted in the achievement of very low emission levels for today's diesels. But considering the future legislation it is required a further drastic reduction. Towards this direction, a multi-zone combustion model is used in the present study to investigate the effect of fuel injection pressure level on the performance and pollutant emissions from a Heavy Duty DI diesel engine. For this purpose it is made use of injection pressure histories obtained from a detailed simulation model at various engine operating conditions. The increase of injection pressure is accomplished by increasing the injector opening pressure from 400 up to 1600 bar.

The fuel injection system of diesel engines is of great importance since it controls the combustion mechanism. The rate of injection and the speed of injected fuel are important parameters for engine operation, controlling the combustion and pollutants formation mechanisms. A fuel injection system simulation capable of predicting the performance of the injection system to a good degree of accuracy has been developed. The simulation is based on a detailed geometrical description of the injection system and in modeling each subsystem as a separate control volume. The simulation starts at the driving mechanism of the fuel pump and describes all parts of the system pump chamber, delivery valve, delivery chamber, connecting pipe and injector. The components of the system are put together and interact as they do in reality. From the cam geometry an analytical expression is derived that gives the pump piston lift as a function of the engine crank angle.