EXPERIMENTAL INVESTIGATION OF THE EFFECTS OF FUEL INJECTION PARAMETERS ON DIESEL ENGINE PERFORMANCE AND EMISSIONS

Abstract

The climate changes and increase in global temperature are the key factors that have mainly amplified the exploration studies of changing fuel injection and other constraints of compression ignition (CI) engines for the abatement of exhaust emissions. In current study, a direct injection (DI), CI engine was run on a test bench for the performance and emission analyses using different nozzles and injection timings. During the experiments, two types of nozzles known as sac and valve covered orifice (VCO) were used with hemispherical cavity and toroidal cavity pistons, respectively. Besides an already existing set of sac type nozzles, six distinct combinations of nozzles with varying cone angles and tip penetration (protrusion) lengths (designated as 135° × 3.5 mm, 140° × 3.5 mm, 145° × 3.5 mm, 150° × 3.5 mm, 150° × 2.5 mm, and 150° × 1.5 mm) were used at three different injection timings comprising 16° before top dead center (BTDC), 13°BTDC and 10°BTDC. Experimental results reveal that VCO nozzles in toroidal combustion chamber (CC) are better than sac nozzles with hemispherical CC, and that wider cone angle nozzles at 10° BTDC give the optimum results in terms of emissions and performance, relative to those of narrower cone angles. The 150° nozzles with 1.5 mm tip penetration give abated carbon monoxide (CO), hydrocarbon (HC) and smoke emissions along with better performance characteristics such as brake specific fuel consumption (BSFC) and brake power (BP), while exhibit slightly higher oxides of nitrogen (NOx) relative to other combinations. Moreover, the same combination also proves to be effective on emission control at 8 mode steady-state cycle.