Investigation the effect of fuel injection strategies on combustion and morphology characteristics of PM in modern diesel engine operated with oxygenate fuel blending

Abstract

• Oxygenated fuel improved size distribution of PM compared to the diesel fuel. • The soot morphological parameters were reduced from combustion of oxygenated fuel compared to the diesel combustion. • The number of soot particles and size of soot agglomerates per TEM image was smaller with increasing injection pressure. • Combined effect of oxygenated fuel and fuel injection strategy has beneficial effect on PM reduction combustion characteristics. • Post-injection strategy modified the morphology characteristics, observing reduction in number of primary particles and radius of soot agglomerates. The soot emissions can be decreased in diesel engine through an improved understanding of the soot formation processes and impact strategies of fuel injection using oxygenated cleaner fuel. The combined effect of the oxygenated fuel (B20) and strategies of fuel injection (FI) timings and pressures on characteristics of combustion and particulate matter (PM) was studied in modern diesel engine. The influence of B20 on PM concentration and morphology parameters such as number of primary particles ( n po ), radius of gyration ( R g ) and fractal dimension ( D f ) were also investigated under different injection strategies. It is found that the average values of cylinder pressure and ROHR (rate of heat release) from B20 combustion are higher than diesel fuel by 3% and 11%, respectively. The results showed that the particulate size distribution (PSD) of PM reduced from the combustion of B20 compared to the diesel fuel combustion. The same trends were obtained for high injection pressure without fuel post-injection (PI), while PSD increased when fuel PI is presented. The soot morphology parameters ( n po and R g ) are reduced during B20 combustion compared with diesel fuel under the various injection strategies. The number and size of soot particles was smaller with high injection pressure for with PI and without PI. Furthermore, the morphology characteristics were slightly modified, observing reduction in n po and R g under engagement of PI for both fuels under different injection pressures. The fractal dimension ( D f ) decreased from the combustion of B20 under PI strategy by 1.41and without PI by 1. 43 when compared to the diesel fuel.