Experimental investigations of the effect of biodiesel utilization on lubricating oil tribology in diesel engines

Biodiesel is an alternative fuel derived from vegetable oils by modifying their molecular structure through a transesterification process. Linseed oil methyl ester (LOME) was prepared using methanol in the presence of potassium hydroxide as a catalyst. The use of LOME in compression ignition engines was found to develop a very compatible engine-fuel system with lower emission characteristics. Two identical engines were subjected to long-term endurance tests, fuelled by an optimum biodiesel blend (20 per cent LOME) and diesel oil, respectively. Various tribological studies on lubricating oil samples drawn at regular intervals from both engines were conducted in order to correlate the comparative performance of the two fuels and the effect of fuel chemistry on lubricating oil performance and life. A number of tests were conducted in order to evaluate the comparative performances of the two fuels such as density measurement, viscosity measurements, flashpoint determination, moisture content determination, pentane and benzene insolubles, thin layer chromatography, differential scanning calorimetry, etc. All these tests were used for an indirect interpretation of the comparative performance of these fuels. The performance of biodiesel fuel is found to be superior to that of diesel oil and the lubricating oil life is found to be longer while operating the engine on biodiesel.