Experimental investigations on the influence of properties of Calophyllum inophyllum biodiesel on performance,combustion, and emission characteristics of a DI diesel engine

The current state of future energy and environmental crises has revitalised the need to find alternative sources of energy due to escalating oil prices and depleting oil reserves. To meet increasing energy requirements, there has been a growing interest in alternative fuels like biodiesel that can become a suitable diesel fuel substitute for compression ignition engine. Biodiesel offers a very promising alternative to diesel fuel, since they are renewable and have similar properties. Calophyllum inophyllum seed oil collected from different restaurants in the Nagapattinam region of South India was converted into methyl esters (biodiesel) by transesterification. Biodiesel produced from C. inophyllum oil was blended with diesel by different volume proportions (25%, 50%, and 75%). Biodiesel and its blends were tested on a direct injection (DI) diesel engine at a constant speed by varying loads from 0% to 100% in steps of 20% to analyse its performance, emission, and combustion characteristics. The results obtained were compared with that of diesel fuel. B25 (27.5%) showed better performance than diesel fuel (26.28%) at full load and B50 showed performances similar to diesel fuel. Smoke density of B25 was slightly (2.6%) higher than that of diesel at full load conditions. At full load, measured carbon monoxide emissions for B25 and B50 were 4% lower than that of diesel. Hydrocarbon emissions for B25 and B100 were 5.37% and 25.8% higher than that of diesel, respectively. Nitrogen oxides (NO_x) emission was lower for all biodiesel blends. NO_x emissions of B100 and B75 were lower than that of diesel by 22.16% and 13.29% at full load, respectively. Combustion profile was smoother, and no knocking problem was observed while operating with biodiesel blends. B75 produced peak cylinder pressure.