Start of low temperature reactions detection based on motoring pressure prediction for partially premixed combustion

Highlights: • Our paper presents a detection method of the start of low temperature reactions. • The detection method is based on a self-adaptive prediction strategy of the motoring pressure. • The prediction error is less than 0.02 bar. • The detection method performed full functionality under different engine operating conditions. Partially premixed combustion aims to reduce NO_x and particulate matter emission without fuel consumption penalty. Low temperature reactions are important for the partially premixed combustion. In the current study, a self-adaptive strategy is introduced to predict the motoring pressure by means of an equivalent isentropic index. The start of the low temperature reactions is detected when the pressure difference between the measured pressure and the predicted pressure is higher than a threshold value. Experimental results show that the maximum variation between the measured and the predicted motoring pressure before the top dead center is less than 0.02 bar. It is also demonstrated that the presented detection method is able to detect the start of the low temperature reactions under different engine operating conditions with varying injection timing, injection duration, number of injections and exhaust gas recirculation rate.