Improved combustion and emission characteristics of ethylene glycol/diesel dual-fuel engine by port injection timing and direct injection timing

In this study, the performance of a diesel ethylene glycol (DEG) dual-fuel engine with four low EG energy ratios (named EGO, EG5, EG10 and EG15 respectively) is tried to improve by port injection timing (PIT) and direct injection timing (DIT). The combustion results show that combustion process is even highly affected by DIT than by PIT. Peak cylinder pressure, peak heat release rates (PHRRs) and pressure rise rate increase with the augmentation of EG energy ratios and advanced DIT. Combustion duration decreases with the increase of EG energy ratios and advanced DIT. Brake thermal efficiency (BTE) can be improved 19.45% by raising EG energy ratios and advancing DIT. In consideration of emission, the emissions of NOx, THC, CO2 and soot decrease followed by the rise of EG energy ratio at the same time, while CO emission increases. The emission is more obviously affected by DIT than PIT. The emission of soot and THC decreases with advanced DIT, while the emission of CO2 and NOx increases. Advanced DIT can reduce PM, and EG can decrease the average diameter of PM. Overall, the advanced DIT, suitable EG energy ratio and proper PIT are expected to achieve optimization on DEG dual-fuel engine in the aspect of performance and emissions.