Effect analysis of injection and ignition timings in opposed-piston two-stroke engine

A numerical simulation on the in-cylinder flow, mixture formation and combustion process of an oppose-piston two-stroke direct injection gasoline engine is conducted to study the effects of injection timing and ignition timing on the mixture formation, combustion process and overall performance of the engine. The results show that with the increase of injection advance angle, the flame developing period shortens and the rapid burning period shortens first then extends and reaches a minimum at an injection advance angle of 100°CA, while with the increase of ignition advance angle, the flame developing period extends and the rapid burning period shortens first then extends and reaches a minimum at an ignition advance angle of 20°CA. Therefore the optimal matching is an injection advance angle of 100°CA with an ignition advance angle of 20°CA, with which the uniform mixing of fuel and air at ignition moment can be achieved, with shorter flame developing period and rapid burning period, corresponding to a higher mean indicated pressure and a lower indicated specific fuel consumption.