Influence of injection timing on performance, emission and combustion characteristics of a DI diesel engine running on fish oil biodiesel

Abstract

The ever increasing demand and depletion of fossil fuels along with environmental concern has prompted search for alternate fuels. Biodiesel is poised to make important contributions to world energy since it is renewable, bio degradable and non-toxic in nature. Various oils have been used in biodiesel production owing to their availability among which fish oil is a significant one. In the present work, experimental investigations were carried out on a single cylinder four stroke, air cooled, constant speed, direct injection diesel engine with a rated output of 4.4 kW at 1500 rpm at different loads and at different injection timings, 21°, 24° and 27°bTDC for studying the performance, emission and combustion characteristics of direct injection (DI) diesel engine fuelled with Ethyl Ester of Fish Oil (EEFO) and its blends. For a diesel engine, injection timing is a major parameter that sensitively affects the engine performance, emission and durability. Oxides of Nitrogen (NOx), Unburnt Hydrocarbon (UBHC) and Carbon Monoxide (CO) emissions in biodiesel blends were lower than diesel, whereas smoke was found to be higher. The brake thermal efficiency for B20 was higher compared to diesel in the entire load spectra. The ignition delay and combustion duration were shorter for biodiesel blends than diesel which results in lower heat release rate, peak pressure and rate of pressure rise. Retardation of injection timing caused decrease in emission and combustion parameters like NOx, HC, CO, peak pressure, ignition delay, combustion duration and heat release rate which increased with advancement in injection timing.