Emissions Characteristics of Small Diesel Engine Fuelled by Waste Cooking Oil

Biodiesel is an alternative, decomposable and biological-processed fuel that has similar characteristics with mineral diesel which can be used directly into diesel engines. However, biodiesel has oxygenated, more density and viscosity compared to mineral diesel. Despite years of improvement attempts, the key issue in using waste cooking oil-based fuels is oxidation stability, stoichiometric point, bio-fuel composition, antioxidants on the degradation and much oxygen with comparing to diesel gas oil. Thus, the improvement of emission exhausted from diesel engines fueled by biodiesel derived from waste cooking oil (WCO) is urgently required to meet the future stringent emission regulations. The purpose of this research is to investigate the influences of WCO blended fuel and combustion reliability in small engine on the combustion characteristics and exhaust emissions. The engine speed was varied from 1500-2500 rpm and WCO blending ratio from 5-15 vol% (W5-W15). Increased blends of WCO ratio is found to influences to the combustion process, resulting in decreased the HC emissions and also other exhaust emission element. The improvement of combustion process is expected to be strongly influenced by oxygenated fuel in biodiesel content