Biodiesel has become more attractive recently, because of its environmental benefits and the fact that it is made from renewable resources. Over the past few decades, most of the countries depending on diesel engines for transportation. Some of its valuable advantages like highest thermal efficiency made it very popular. At the same time, the cost of diesel fuel is increasing, due to the depletion of fossil fuels. In this current scenario, we need an alternative fuel instead of diesel fuel. Many of the researchers have successfully placed several works on generating energy from different types of alternative sources including solar and some kind of conversion processes including renewable agricultural products into liquid fuel. One of the biggest challenges for developing countries in relation to energy consumption is to develop and implement technologies that help to improve efficiency of automobile engines, also to reduce the emissions of harmful gases and particulate matters. In order to avoid environmental impacts, emissions are reduced or eliminated by introducing renewable energy resources. The present research chronicles the production and testing of renewable biodiesel fuel derived from virgin coconut oil on a diesel engine, to analyses the engine performance and emission characteristics. In the first phase of work, production of biodiesel fuel from virgin coconut oil using transeterification process with two types of catalysts (homogenous and heterogeneous). The preliminary results shows that, with the addition of homogenous catalyst called Potassium Hydroxide (KOH) with methanol shows much higher activity than that of heterogeneous catalysts, and it shows more similar properties with diesel fuel. The results obtained from the chemical test and physicochemical properties of transesterified biodiesel fuel clearly proves the above-mentioned statement. The chemical tests such as GCMS and FT-IR clearly shows that the biodiesel fuel has sufficient amount of volatile components and functional groups. Then, physicochemical properties include, Fire point, Flashpoint, density, and viscosity were analyzed. Finally, Engine performance and Emission characteristics were analysed to confirm, whether this biodiesel fuel is suitable for diesel engines, without any engine modifications. It was found to be, the transesterified virgin coconut oil biodiesel has similar properties to that of the diesel fuel. From the physiochemical properties and engine performance clearly shows that, coconut oil biodiesel is suitable for diesel engine on blending, at a blending percentage level of 20% with conventional diesel fuel. Since the obtained transesterified biofuel can be used as an alternative fuel for diesel engines. The several journal reports and find outs from experimental investigation clearly depicts that the efficiency of the transesterified biofuel mainly depends upon the amount of catalyst adding and type of catalysts present in the biofuel, whether it is homogenous or heterogeneous catalyst is suitable with methanol. Finally, from the analysis made from biodiesel fuel. Coconut Oil Biodiesel fuel has less emission characteristics than that of the diesel fuels.

Keywords : Biodiesel fuel; virgin coconut oil biodiesel; homogenous catalyst; heterogeneous catalyst; transesterification process.