|Abstract||Compression ignition (CI) engines are widely used in transportation, industrial and agriculture sectors. The main fuel for CI engine is petro diesel and the reserves of petroleum is fastly depleting. The life of fossil fuels has become limited in the present era, where the use of energy has been growing faster than the world population. The increase in the emissions rates of greenhouse gases (GHDs) produced from the use of these fossil fuels presents a threat to the world climate. Hence, there is need to search and find ways of using alternative fuels, which will be economical, energy-efficient, and should emit low levels of pollutants. In the recent past, the utilization of biodiesel in CI engines has significantly increased. Many countries have started using biodiesel derived from edible or non-edible seeds, as transportation fuels. However, the availability of seeds is limited, discouraging the use of biodiesel. By finding such difficulties, current research work is aimed to replace the some percentage of biodiesel with tyre pyrolysis oil (TPO). In the first phase of work, TPO was blended with Jaropha methyl ester (JME), and used as an alternative fuel in a single cylinder, four stroke, air cooled, direct injection (DI) diesel engine developing 4.4kW. The engine behavior in terms of combustion, performance and emission of the engine were evaluated and the results are presented. Further optimization was carriedout using VIKOR to find the best blend. It was found that the blend comprising 20% TPO and 80% JME gave better performance and lower emissions compared to diesel operation. After optimizing the best blend, investigations were carried with optimum blend at varied injection timings, injection pressures and compression ratios and the results are presented in thesis. The study on the effect of blending TPO with JME on oxidation stability was also evaluated. Further, durability analysis was carried out to evaluate its feasibility for long term operation.