An assessment on injection pressure and timing to reduce emissions on diesel engine powered by renewable fuel

Abstract

Fuel injection pressure and fuel injection timing are significant injection parameters, which have a greater impact on engine performance, combustion, and emission. The main focus of this work is on improving the emissions and performance of the single cylinder diesel engine by changing the injection parameters with the engine being powered by novel Syzygium cumini oil biodiesel at various proportions (i.e., B30,70,100). In addition to that, the investigations were directed towards achieving the effective usage of biodiesel for the substitution of fast depleting diesel fuel. The experimental work was conducted on single cylinder, water-cooled, direct injection compression ignition engine at a constant speed of 1500 rpm with static fuel injection timing 23° before top dead centre and pressure of 200 bar. The engine tests were conducted at different fuel injection pressures (200, 220, 240 and 260 bar) and different injection timings (21, 23 and 25 oCA BTDC). Advancing the injection timing by 2 deg crank angle and increasing the fuel injection pressure to 240 bar resulted in superior performance. For instance, brake thermal efficiency of diesel and B30 increased by 17.85% and 16.66% respectively. While retarding fuel injection timing to 21-degree crank angle had an adverse effect on engine performance. B30 blend gave a superior performance compared with the other biodiesel blends. By advancing injection timing and increasing fuel injection pressure, hydrocarbon and carbon monoxide emissions for B30 blend were found to be 46.15% and 15.9% lesser than static fuel injection conditions. Maximum of 28.7% reduction in smoke emission was observed for advancing injection timing and increasing fuel injection pressure compared with the static injection conditions. But, nitric oxide emissions were relatively higher for advance injection timing and higher fuel injection pressure. The results led to the decision that advance injection timing and increasing fuel injection pressure could be chosen as better injection parameters for a diesel engine being powered by novel Syzygium cumini oil biodiesel with the massive reduction in emissions.