<![CDATA[The increasing demand for diesel fuel and the environmental impact of the consumption of fossil fuels has encouraged the development of renewable alternative fuels. Coconut oil biodiesel is a promising alternative due to high cetane number, biodegradability and abundant availability but its application is limited due to relatively high viscosity. The present work aims to evaluate the effect of blending coconut oil biodiesel with diesel fuel and the addition of citronella oil (Cymbopogon nardus) as a natural bio-additive on the quality of the fuel. Citronella oil in concentration of 0 to 1.0% (v/v) was prepared in four biodiesel-diesel blends (B40, B50, B60 and B70). The fuel properties tested were density, kinematic viscosity, flash point, carbon residue, water content and cetane number according to ASTM and SNI standards . The results indicated that the fuel quality improved with increasing biodiesel content and citronella oil concentration. The cetane number and flash point increased steadily which indicated better ignition quality and improved fuel handling safety. Meanwhile, the density, viscosity, carbon residue and water content were within the permissible limits of fuel standards. The B70 blend with 1.0% citronella oil exhibited the best overall performance among all the formulations, with the maximum cetane number, flash point and satisfactory physicochemical properties. The results show that citronella oil is an efficient natural bio-additive to improve the quality of biodiesel-diesel blends from coconut oil. The proposed formulation has a good potential to be used as sustainable and environmentally friendly alternative diesel fuel supporting renewable energy utilization and energy diversification.]]>
