Optimization of Injection Timing in CI Engine Using Blends of Straight Vegetable Oil

The present experiment is done to optimize engine performance using straight vegetable oil by varying its injection timing. We take jatropha curcas oil as potential fuel for the compression ignition (CI) engines because the cetane number of jatropha oil is quite high and comparable with diesel fuel. Jatropha curcas oil has high viscosity but is lower than other vegetable oils. The viscosity of jatropha oil is reduced by blending it with diesel in different proportions. The blends of varying proportions of jatropha oil and diesel were prepared, analyzed and compared with diesel fuel by running a four stroke CI engine. Also the effect of injection timing is studied and applied in the test. Fuel injection timing was advanced by 3 �¦ means injection occurred 24 �¦ before top dead centre (BTDC) as the designed for 27 �¦ before TDC targeting diesel as prime fuel. The purpose of advancing injection timing was to match the cetane number of oil blends with diesel. As we know cetane number is inverse function of ignition delay. For better combustion properties the ignition delay must be low as much as possible.