Effect of Compression Ratio on Diesel Engine Performance and Emission Fueled with Tamanu Oil Methyl Ester and its Blends

Biofuels are renewable, nontoxic and ecofriendly fuels that can play an important role in automobile industries. They can successfully replace diesel fuel and helps in decreasing the import of crude oil. The discarded seed of CalophyllunInophyllum which are planted in India mainly to prevent soil erosion is considered as the possible source for extracting biodiesel. The tamanu oil extracted had a fatty acid value of 48 mg KOH/g, therefore a two stage esterification processes with acid and base catalyst were used for converting it into biodiesel. The fuel was then tested for properties such as viscosity, calorific value and carbon residue using standard test procedures and found to be analogous with diesel, which makes it possible to use this alternate fuel in the existing engine without any modification. A single cylinder, four stroke, constant speed, variable compression ratio, direct injection diesel engine developing 5KW power with provision for computerized data acquisition is used to evaluate the performance and emission characteristics. The test results were analyzed for biodiesel and its blends in comparison with standard diesel at different compression ratios (16:1, 18:1, 20:1 & 22:1). The performance and emission results of the diesel engine revealed that biodiesel can be blended with diesel up to 40% at an optimum CR of 20, in order to get improved performance and reduced emission.