The performance of the engine using fuels from bio origin to diesel and the limited availability of the fossil fuel leads to an increasing attention to the former. As for as India is concerned ethanol and methyl esters of the vegetable oils are the promising alternative fuels for diesel engines. In the present investigation, the effect of hybrid fuel blends comprising diesel-ethanol- vegetable oil (methyl esters of pungamia oil) in a multi cylinder, naturally aspirated, direct injection diesel engine is studied in terms of their performance, emission and combustion characteristics. Compared with the engine operated on diesel fuel.
The combustion parameters such as peak cylinder pressure, angle of maximum pressure, delay period, cumulative heat release, heat release rate, rate of pressure rise, combustion duration, angle of 5%, 10%, 50% and 90% mass burned and Indicative Mean Effective Pressure (IMEP) are also calculated and compared. The brake thermal efficiency of the engine operated with hybrid fuel blends, D80P10E10 (diesel 80%, pungamia oil methyl ester 10% and ethanol 10% by volume) and D10P80E10, increases 3.08 % and 5.20% as compared with diesel at 50% load and 1600 rpm. The smoke emission for D80P10E10 was lower than the other blends and oxides of nitrogen were found to be reduced for hybrid fuel blends as fuel. The Hydrocarbon emission was 20% higher for D80P10E10 than diesel fuel, however when percentage of Pungamia Methyl Ester (PME) increases in the blends 11% reduction was achieved for D10P80E10. The carbon dioxide emission was similar to the base diesel. It can be concluded from the present work that the renewable hybrid fuel blend is a suitable substitute for conventional diesel fuel.