Performance evaluation, emission characteristics and economic analysis of four non-edible straight vegetable oils on a single cylinder CI engine

An experimental investigation was carried out to analyze the performance and emission characteristics of a compression ignition engine fuelled with non-edible straight vegetable oils of Neem, Mahua, Linseed and Castor oil. Straight vegetable oils posed operational and durability problems when subjected to long term usage in CI engine. These problems are attributed to high viscosity, low volatility and polyunsaturated character of vegetable oils. Hence, process of transesterification is found to be effective method of reducing viscosity and eliminating operational and durability problems. Fuel preheating in the experiments for reducing viscosity of neat oils has also been done by a specially designed heat exchanger, which utilizes waste heat from exhaust gases. The test is conducted on single cylinder DI engine at constant speed of 1500 rpm. The performance parameters evaluated include thermal efficiency, brake specific fuel consumption (BSFC), brake specific energy consumption (BSEC), and exhaust gas temperature whereas exhaust emissions include mass emissions smoke. The results of the experiment in each case were compared with baseline data of diesel. Significant improvements have been observed in the performance parameters of the engine as well as exhaust emissions with use of neem, mahua and castor oil. Economic analysis was also done in the study and it is found that use of vegetable oil as diesel fuel substitutes has almost similar cost as that of mineral diesel.