Effect of cetane coupled with various engine conditions on diesel engine combustion and emission

Abstract

Tests to study the effect of five different cetane number (CN) diesel fuels (CN of 51, 53.9, 55.3, 57.4, and 59.3) coupled to multiple operating conditions (multiple speeds and loads) on diesel engine performance in a single diesel engine. The results showed that at 25% load, the onset of combustion heat release was delayed with decreasing CN, and the in-cylinder pressure and heat release rate increased. However, the CN = 53.9 fuel chain alkane content was the highest, which led to the early onset of combustion; as the load continued to grow, the effect of CN on the beginning of heat release combustion became smaller. The values of brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) depend on the calorific value and CN of the fuel. The lower CN results in higher NOx, HC, and CO emissions, especially at low load conditions, where CN changes on emissions are more pronounced. As the load increases, the peak number concentration and total mass of particulate matter (PM) show a trend of increasing and then decreasing. The peak number concentration corresponds to the particle size-shifting toward the small particle size. The engine load change on PM emission is more significant than speed change.