Effect of cetane coupled injection parameters on diesel engine combustion and emissions

Abstract

Experiments on the effects of different cetane coupled injection parameters on diesel engine combustion and emissions were conducted on a supercharged 4-cylinder direct injection diesel engine. The results showed that with the increase of cetane number (CN), the peak in-cylinder pressure and heat release rate of fuel decrease, the coupling injection pressure increase, CO and HC emissions decrease, NOx emissions increase, the number concentration and total mass of particulate matter (PM) decrease. As the CN increases, the peak in-cylinder pressure decreases, the coupling injection timing is delayed, the peak heat release rate increases, brake thermal efficiency (BTE) decrease, brake specific fuel consumption (BSFC) increases, CO and HC emissions increase, NOx emissions decrease, and the number concentration and total mass of PM increases. Fuel characteristics and injection timing significantly influence ignition delay time and combustion duration, where CN = 53.9 fuel has no pre-injection to release heat at different injection timing, which has a more substantial impact on in-cylinder pressure and heat release rate.