Experimental Investigations of Palm Oil Biodiesel Operated in a DI Diesel Engine

Abstract

The growing demand for sustainable energy sources and stringent emission regulations have intensified research on renewable fuels for compression ignition (CI) engines. Among various alternatives, palm oil biodiesel has gained considerable attention due to its high availability, biodegradability, and compatibility with existing diesel engine infrastructure. In this study, experimental investigations were conducted to evaluate the performance and emission characteristics of palm oil biodiesel and its blends in a single-cylinder, four-stroke direct injection (DI) diesel engine operating at constant speed under varying load conditions. Fuel blends including B20, B40, and B100 were tested and compared with conventional diesel. Key performance parameters such as brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC), along with emission characteristics including carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and smoke opacity were analyzed. The results indicate that biodiesel blends exhibit slightly lower BTE and higher BSFC compared to diesel due to their lower calorific value and higher viscosity. However, significant reductions in CO, HC, and smoke emissions were observed owing to the oxygenated nature of biodiesel, which enhances combustion efficiency. A marginal increase in NOx emissions was recorded with higher biodiesel content, attributed to elevated in-cylinder combustion temperatures.Among the tested fuels, the B20 blend demonstrated the best compromise between engine performance and emission reduction. The findings confirm that palm oil biodiesel can be effectively utilized in DI diesel engines without major modifications, offering a viable and environmentally sustainable alternative to conventional diesel fuel.