Impact of Waste Cooking Oil Biodiesel on Performance, Exhaust Emission and Combustion Characteristics in a Light-Duty Diesel Engine

The idea of using biodiesel as substitute fuel for fossil diesel is promising. The boom in biodiesel, however, has raised increasing concern about food shortage throughout the world and may translate into a food crisis. To avoid using food resources for fuel purposes, huge emphasis is currently being put on shifting to alternative non-food feedstocks including waste cooking oils. This study investigated the effects of biodiesel derived from waste palm oil-based cooking oil on performance, exhaust emissions and combustion characteristics in a light duty compression ignition engine. A total of three sets of fuel blends were studied: 10%, 20% and 30% volumetric blends (B10, B20 and B30) of waste cooking oil methyl ester (WME) with fossil diesel. In this study, the experimental work was carried out with a single cylinder, four-stroke, direct injection compression ignition engine. The experiments were conducted under constant torque of 20 Nm and at five different engine speeds. The results for performance, emissions and combustion were compared with those achieved with baseline diesel. Improvements in brake thermal efficiency (BTE) could be found for some of the biodiesel fuel blends and were higher than those for diesel fuel. It was observed that most of the pollutant emissions were reduced to some extent with WME fuels in the blends. The cylinder pressure profiles for WME fuel blends were comparable with those for baseline diesel, but some variations in peak pressure were observed. The study revealed that the engine performance, emissions and combustion for an engine fueled with WME fuel blends are comparable to those of engines run on baseline diesel.