Fast discrete resolution of combustion process in diesel engine based on cylinder pressure parameter

Combustion information is needed to apply engine control system, current calculation methods for combustion process are analyzed briefly, cylinder pressure difference method was introduced to study combustion condition. Cylinder pressure is used to be combustion indication flag in order to meet combustion information requirement, based on cylinder pressure parameter, by means of pressure difference method, math algorithm of fast dispersed resolution to combustion process by pressure difference is presented. Combustion intensity, phase and heat-releasing rate are provided to describe combustion condition. Ignition commencement angle, maximal burst pressure and its angle, and bar-center point in pressure difference curve are selected as character parameters to specialize overall combustion character. Combined with cylinder pressure of real engine, relation of pressure character index with injection timing and injection quantity was resolved by simulation and measurement of pressure data, and change trend of each pressure character index with diesel engine emission NOx based on experimental data was analyzed. The results indicated that fast discrete resolution for combustion process with pressure parameter was effective and pressure character index could reflect combustion character.