In recent years,oil prices have been rising rapidl y again and there is a major concern for the long t erm availability of fossil fuels. This and the growing concern for our environment have created a much larger market for r enewable resources. The idea of using vegetable oils instead of fossil diesel fuels has resurfaced as a way to minimize the net carbon footprint left by emissions from compression ignition (CI) engines. Straight vegetable oils (SV Os) have their fair share of problems in unmodified CI engines. Th ese problems include:cold-weather starting;pluggi ng and gumming of filters lines,and injectors;engine kno cking;coking of injectors on piston and head of en gine;carbon deposits on piston and head of engine;excessive en gine wear;and deterioration of engine lubricating oil. Vegetable oils decrease power output and thermal efficiency w hile leaving carbon deposits inside the cylinder. To avoid some of these problems,vegetable oils hav e been converted via a chemical process (transester ification) to result in a fuel more like fossil diesel. The resul ting fuel is biodiesel,a biodegradable and nontoxi c renewable fuel. Furthermore,biodiesels have reduced molecular weig hts (in relation to triglycerides),reduced viscosi ty,and improved volatility when compared to ordinary veget able oils. Most CI engines can run on biodiesels wi thout modifications;however to optimize combustion the i njection timing should be adjusted. https://www.ijiert.org/paper-details?paper_id=140418