Performance and Emission Characteristics of Diesel and Jatropha Oil Blends in a Direct Injection Variable Compression Ratio Ignition Engine


Department of Mechanical Engineering, National Institute of Technology Agartala, India


The rapid depletion of conventional fuel and fluctuation of Diesel price in the global market have promoted research for alternative fuels for Diesel engine. Among the different alternative fuels, vegetable oil having fuel properties similar to Diesel has an acceptable engine performance. Vegetable oils are producing less CO2 emissions to the atmosphere because of their agricultural origin and less carbon content compared to mineral Diesel. It also reduces import of petroleum products. In the present investigation, an experimental study is carried out on an I.C.E laboratory in single cylinder, four-stroke VCR, direct injection Diesel engine to analyze the performance and emission characteristics of pure Diesel and Jatropha oil-Diesel blended fuels with various blend ratios. The measurements are recorded for the compression ratio 16, 17 and 18 with varying load from idle to rated load of 5.2 kW. Comparative results are given at constant engine speed, variable compression ratio and different engine BMEP for baseline Diesel and Jatropha oil-Diesel blended fuels revealing the effect of Diesel and Jatropha-Diesel blended fuels’ combustion on engine performance and exhaust emissions. The results show that for same blend, performance of the engine is improved considerably with the increase in CR. Thermal efficiency, exhaust gas temperature and emission parameters such as NOX, HC and CO at CR 18 with blends containing up to 30% (by volume) Jatropha oil is comparable to that of diesel fuel. So, blends containing up to 30% (by volume) Jatropha oil at CR 18 can be honestly used as an alternative fuel without any engine modification.