Engine Performance and Emission Products of Pure Diesel and Multi-Feedstock Blended Biodiesel

Due to the ever-reducing conventional petroleum resources, considerable research on renewable energy sources such as biodiesel as a possible “greener” substitute fuel for internal combustion engines is needed. This study aims to compare the engine performance and emission results of various blends of pure diesel and a multi-feedstock (MFS) biodiesel when used in a naturally aspirated air-cooled, single-cylinder direct injection diesel engine. The engine was coupled to a dynamometer for torque measurement and output data transmitted to a PC for post-processing and displayed using customized programs in the computer. Engine combustion products — Nitrogen Oxide emissions (NOx), Hydrocarbons (HCs), Carbon monoxide (CO) and Carbon dioxide (CO2) — were measured and are presented alongside performance properties including brake-specific fuel consumption (BSFC), engine efficiency, torque and power. The experimental results show that, relative to diesel, biodiesel had approximately 3–24% decrease in torque, 4–11% decrease in power, 11–32% increase in BSFC and 8–29% general reduction in engine efficiency. However, biodiesel reduced the emissions of CO (1.5–6%), CO2 (13–34%) and unburned HCs (3–25%), while NOx emissions were increased significantly (12–48%). These results indicate that smaller percentages of biodiesel (20% or less) could be blended with pure diesel and used in a diesel engine, without any engine modifications, as an alternative and environmentally friendly fuel and without significantly compromising engine performance.