Investigating the influence of oxygenated fuel on particulate size distribution and NOX control in a common-rail diesel engine at rated EGR levels

Abstract

The effect of butanol-diesel blend (B20) and different rates of exhaust gas recirculation (EGR) on particulate matter (PM) characterisation and NOX emissions were investigated in this experimental work. The different rates of EGR (0%, 15% and 30%) and oxygenated fuel (B20) were used in this study. The brake thermal efficiency (BTE) of the engine increased under without used EGR technique compared to the presence of EGR during combustion process for B20 and diesel fuel. Further, higher BTE produced during the combustion of B20 than that produced from combustion of diesel for different rates of EGR. The BSFC slightly increased with B20 combustion compared to the diesel combustion. The cylinder pressure and ROHR improved with combustion of B20 under without using EFR. The results showed that PM reduced from the combustion of B20 more than to the diesel fuel for different rates of EGR. Besides, the average of particle diameter reduced from B20 combustion by 20, 22 and 25 nm compared to the diesel by 31, 37 and 43 nm for 0%, 15% and 30% of EGR, respectively. The soot particles generated from B20 combustion are lower than to the diesel fuel combustion for different rates of EGR. Lower level of NOX emissions can be achieved with using EGR (15% and 30%) than to the without EGR technique, this effect is more clearly with oxygenated fuel. It is indicated that the EGR dramatically increase the THC and CO emissions when exceeds the 30% with no obvious influence on NOX emissions.