Abstract
The depleting natural energy resources and emissions from diesel engine caused by petroleum fuels attract a need for alternative fuels such as biodiesel which will be renewable and demotes the emission. Biodiesels are world’s future energy needs which expected to deflate the dependence on imported petroleum and revitalize the economy by increasing demand and prices for agricultural products. The recent research has been made in biofuels to extract biodiesel from vegetable oil and animal oil at an economical cost. In this present review, the need of biodiesel in present scenario and the influence of biodiesel and additives from different feedstock based on properties, combustion, performance, and emission characteristics fuelled in CI engine under different operating conditions are illustrated. It is reported that the oxygenating properties of biodiesel increase brake specific fuel consumption (BSFC) and consequently brake thermal efficiency (BTE) and considerably reduce hydrocarbons (HC), carbon monoxide (CO) emission. In biodiesel blends, BSFC increases with a decrease in BTE. Biodiesel shows slightly subservient performance than diesel. However, biodiesels are endowed with some disadvantages like lower calorific value, cold flow problems and higher density. To overcome these problems different additives are blended in biodiesels. It enhances the properties of biodiesels, improves the diesel engine performance, reduces the emissions and ultimately suits international fuel and emission standards. It is reported that all emissions except oxide of nitrogen (NOx) are reduced with the addition of additives. This paper proposes certain biodiesel fuels with additives to replace petroleum fuels in comparison of performance and emission.
