Abstract: The scarce and rapidly depleting conventional petroleum resources have promoted research for alternative fuels for internal combustion engines. Among various possible options, fuels derived from vegetable oils/animal fats present promising ‘‘greener’’ substitutes for fossil fuels. Vegetable oils, due to their agricultural origin, are able to reduce net CO2 emissions to the atmosphere along with import substitution of petroleum products. However, several operational and durability problems of using straight vegetable oils in diesel engines have been reported in the literature, which are because of their higher viscosity and low volatility compared to mineral diesel fuel. In the present study, experiments were conducted using mineral diesel and jatropha-diesel blends to study the emissions and performance characteristics of diesel engine. A single cylinder, four stroke, constant speed, water cooled, variable compression ratio engine was used for the experiments. The acquired data were analyzed for various parameters such as brake thermal e?ciency (BTE), brake power (BP), brake speci?c fuel consumption (BSFC), brake mean effective pressure (BMEP) and emissions such as CO2, CO and HC emissions. While operating the engine on jatropha-diesel blends, performance and emission parameters were found to be very close to mineral diesel for lower blend concentrations.

Keywords: Jatropha, VCR Engine, Emissions, BTE, BSFC.