Abstract

In this study, a non-edible vegetable oil was produced from jatropha fruits as a substitute fuel for diesel engines and its usability was investigated as pure oil and as a blend with petroleum diesel fuel. A direct injection (DI) diesel engine was tested using diesel,Jatropha oil, and blends of Jatropha oil and diesel in different proportions. A wide range of engine loads and Jatropha oil/diesel ratios of 5/95% (J5), 10/90% (J10), 20/80% (J20), 50/50% (J50), and 80/20% (J80) by volume were considered. The following performance parameters were measured; brake thermal efficiency, brake specific fuel consumption and CO and CO₂ emissions. No significant change in brake thermal efficiency and brake specific fuel consumption was experienced up to J20 ratios. However, higher blends suffered from deterioration in efficiency and fuel consumption about 10 to 25%. At low load operations, CO₂ emission with blends was lower than that of diesel, whereas, at high loads, CO₂ emission became higher with a higher percentage of Jatropha oil in the blends. However, CO emission with blends was much higher than that of diesel; the higher the percentage of Jatropha oil in the blend, the higher the CO emission.

Key words:  Non-edible vegetable oil, Jatropha oil, diesel-Jatropha oil blends, viscosity and heating, DI diesel engine, performance, emissions