Experimental Investigations of Engine Durability and Lubricating Oil Properties of Jatropha Oil Blends Fuelled DI Diesel Engine

Current demand of transport fuel requires exploring every possible plant resource of engine fuel which can deliver satisfactory performance, emission, combustion and engine durability. Blending smaller quantity of Jatropha oil with mineral diesel is one of the simplest alternatives which can be put into application from technical and availability perspective. High viscosity of Jatropha oil (vegetable oil) comes into acceptable range upon blending with mineral diesel upto 20% (v/v). After ensuring satisfactory performance, emission and combustion characteristics, engines were subjected to long-term endurance test of 512 hour for comparing long-term performance of J5 and J10 blends vis-a`-vis mineral diesel, in the present experimental investigation. In the long-term endurance test, the effect of use of Jatropha oil blends on wear of various engine parts and lubricating vis-a`-vis mineral diesel were evaluated. The deposits on the vital engine parts were found to be slightly higher on J10 fuelled engine while it was comparable to mineral diesel for J5 fuelled engine. The piston rating carried out on the pistons of the three engines reflected that the J5 fuelled engines demonstrated reasonable long-term performance in comparison to mineral diesel fuelled engine while performance of J10 fuelled engine was slightly inferior. J5 and J10 fuelled engine’s lubricating oil shows higher reduction in lubricating oil viscosity and flash point compared to mineral diesel, thus indicating possibly higher fuel dilution. Fe, Pb, Cr, Zn wear metal debris in the lubricating oil are lower for J5 and J10 compared to mineral diesel engine’s lubricating oil however Al content in the lubricating oil is slightly higher for J5 and J10 compared to mineral diesel engine’s lubricating oil. Physical wear measurement of vital engine parts indicate relatively higher wear of liner bore, piston rings and big end bearing for J5 and J10 fuelled engine while wear of valve mounting, piston, gudgeon pin, crank pin was found to be relatively lower than mineral diesel fuelled engine. It was found that the wear of J5 engine liners is higher compared to mineral diesel fuelled engine. However wear of J10 fuelled engine liner is found to be relatively lower compared to mineral diesel fuelled engine.