Phenomenological combustion modeling of a direct injection diesel engine with in-cylinder flow effects

A cycle simulation program is developed and its predictions are compared wi th the test bed measurements of a direct injection(DI) diesel engine. It is based on the mass and energy conservation equations with phenomenological models for diesel combustion. Two modeling approaches for combustion have b een tested; a multi-zone model by Hiroyasu et al (1976) and the other one c oupled with an in-cylinder flow model. The results of the two combustion mo dels are compared with the measured imep, pressure trace and NOx and soot e missions over a range of the engine loads and speeds. A parametric study is performed for the fuel injection timing and pressure, the swirl ratio, and the squish area. The calculation results agree with the measured data, and with intuitive understanding of the general operating characteristics of a DI diesel engine.