eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2015-12-25 12 3 2387 2392 10.13005/bbra/1915 4229 article In this research, the performance characteristics and exhaust emissions of an air-cooled single-cylinder diesel engine were investigated using different mixtures of biodiesel fuel derived from castor oil. The evaluations were carried out at different engine loads (0, 25, 50, 75 and 100%) and engine constant speed of 1950 rpm. For all of the investigated loads, the generated power by the engine using the different biofuel mixturesincreased.The specific fuel consumption decreased for biodiesel blends in low loads compared to diesel fuel. The lowest emissions of CO pollutant for all of the evaluated mixtures were observed at middle engine loads and the emissions for biodiesel mixtures were lower than those of pure diesel fuel. Emissions of CO₂ for all of the evaluated mixtures were lower than those of pure diesel and the highest decrease (8.5%) was observed for B15 mixture. Compared with pure diesel fuel, the emission of NOx for B5 and B10 mixtures increased insignificantly, whilst the emission decreased for B15 and B20 mixtures. The emissions of unburnedhydrocarbons by the engine decreased by 21% compared to pure diesel engine. https://www.biotech-asia.org/vol12no3/experimental-investigation-of-performance-and-emissions-in-light-duty-diesel-engine-under-different-loads-using-diesel-biodiesel-fuel-blends/ Biodiesel; performance; pollutant; air-cooled diesel engine