Effects of retarded fuel injection timing on combustion and emissions of a diesel engine fueled with canola biodiesel

Abstract

In this study, retarded injection timing was investigated to overcome higher NOx emissions of a direct injection diesel engine fueled with diesel fuel (90%)/canola biodiesel (10%) blend. The experiments were performed at the maximum torque speed (2200 rpm) under four loads (3.75 Nm, 7.5 Nm, 11.25 Nm and 15 Nm) and three injection timings (original −28 °CA, 26 °CA and 24 °CA bTDC). The effects of the retarded fuel injection timings on the performance, the emissions and the combustion were examined in detail. The changes in the cylinder pressure, the combustion timing, the heat release rate, the fractions and the durations of premixed and diffusion combustion phases, the injection and the ignition delays, NOx, total hydrocarbon, CO, CO2, smoke, break specific fuel consumption and break thermal efficiency were determined and presented in the paper. The experimental results showed that the injection retardation of 2 °CA could satisfy lower NOx and break specific fuel consumptions without significant adverse effects on the other engine parameters, while the further retarding of the injection timing deteriorated the parameters. The retarded injection timing of 2 °CA provided decreases in NOx up to 11% and in BSFC up to 2.7%.