Property development of fatty acid methyl ester from waste coconut oil as engine fuel

The properties, performance, and exhaust emissions of a four-cylinder indirect injection diesel engine fueled by FAME from waste coconut oil was evaluated in this study. Polymerization and carbon deposits on fuel-injector nozzles were also monitored. Ordinary diesel (OD) oil was used as a benchmark for comparison purposes. Tests included measuring high heating value, kinematic viscosity, specific density, cetane index, pour point, flash point, and Conradson carbon residue. Results showed that, the high calorific value decreased with increased coconut oil in coconut-oil blends. On average, the calorific value of all coconut-oil blends were about 6% lower than that of OD fuel. Density increased with increased coconut oil in coconut-oil blends because of the higher amount of carbon atoms in coconut-oil molecules. As a result, viscosity also increased with increased coconut oil in blends. Other properties of blended fuels varied according to their physicochemical properties. Results also showed that the brake power output of engine increased by about 5% when fueled by 30% coconut-oil-blended fuel. The average specific fuel consumption of coconut-oil-blended fuels increased by 7–10% compared with OD oil. The exhaust emissions of blended fuel were found to be much cleaner, containing less CO, HC, NOx, and smoke and benzene concentration. The coconut-oil-blended fuel also produced low particulate emission and carbon deposit on injector nozzles. For each coconut-oil-blended fuel, the engine did not have any starting difficulty and combustion noise at >25°C. The coconut-oil-based fuel also did not pose a severe environmental threat because of its low sulfur content