Comparison of engine characteristics with biodiesels produced from fresh and waste cooking oils

The research focus on alternative fuels has intensified and is gaining momentum owing to depleting crude oil reserves and the adverse environmental effects associated with the use of fossil fuels in automotive engines. In the present work, the feasibility of producing biodiesel from waste cooking oil (WCO) and utilizing it in a light-duty diesel engine is investigated. The composition and properties of biodiesel produced from restaurant waste sunflower oil are compared with those of fresh sunflower oil biodiesel, and the differences are found to be negligible. The effects of replacing fossil diesel with WCO biodiesel in comparison to fresh sunflower oil biodiesel are studied in a light-duty diesel engine under constant speed and varying load conditions. The results show that the use of WCO biodiesel increases brake specific fuel consumption by 22%, reduces carbon monoxide and smoke emissions by 6.3% and 69.2% respectively, and increases emission of oxides of nitrogen by 5.6%. Further, the engine characteristics are found to be almost the same between fresh and WCO biodiesels. Based on the results obtained, it is recommended to use WCO biodiesel as a potentially low-cost replacement for diesel in automotive engines to circumvent food versus fuel and waste oil disposal problems.