Combustion control device for diesel engine

摘要

The diesel engine conducts exhaust gas recirculation and low temperature pre-mixed combustion at a low compression ratio. An ambient temperature at initiation of combustion (t2) determined from compression ratio and intake gas temperature or engine load. A target temperature (T1) which supports pre-mixed combustion is determined. When the ambient temperature at initiation of combustion (t2) is determined to be in a region that is lower than the target temperature (T1), a temperature increase control device is operated which increases the temperature of the operational gases in the cylinder so that the temperature at initiation of combustion exceeds the target temperature (T1). The main fuel injection timing is placed in the range of 5 DEG - 20 DEG of the combustion top dead center so that the main combustion temperature is above a fixed value. In this way, low temperature pre-mixed combustion is stabilized at low load at which combustion becomes unstable when compression ratios are low. <IMAGE>