Waste Vegetable Oil and Coconut Oil as an Alternative Fuel For Diesel Engines

Abstract

The subject of alternative fuels for diesel engines has become a popular one, particularly among environmentalists and political activists. In an effort to thwart human-induced environmental problems, such as global warming and climate change, increased efforts are taking place to find alternatives to the greatest producers of harmful greenhouse gases. Diesel fuel is one such producer. When burned, diesel emits carbon dioxide and other polluting gases that hurt the earth's atmosphere. Fortunately, some promising technologies, both existing and in development, can offer large-scale environmental solutions at reasonable costs. In this regard, vegetable oils are proved to be promising options. In this study waste soybean oil and raw coconut oil is used as alternative fuel. The lower heating value is found to be lower, on the other hand density and viscosity of waste soybean oil and coconut oil are found to be very close to that of diesel at higher temperature. In the present study, waste soybean oil and coconut oil is preheated and blended with 20% diesel fuel and their effects on engine performance is investigated on a direct injection, 4 stroke, single cylinder diesel engine. Engine performance has been evaluated with the help of both conventional performance parameters, viz; brake thermal efficiency and brake specific fuel consumption. In addition, the exergy analysis has been studied for the diesel as well as for alternative fuels. Major portion of the fuel chemical exergy is destroyed due to friction, cooling, combustion, etc. and due to exhaust gases.