Abstract
were also investigated. Proper formulations of blended vegetable oils for using in conventional diesel engines are of main interests. However it is difficult to obtain the highest engine performance when using blended vegetable oils because those engines are not designed for vegetable oils. In this study, modifications of an injector of DI engine were made to be suitable for the use of blended vegetable oils. The coconut oils were blended with diesel oil by the amount of 10%, 20%, 30%, 60% and 80% by volume. A conventional injector nozzle with 4 holes, modified to have 3 holes and 2 holes, was tested in a small CI engine. The effects of fuel spray based on the numbers of the holes on the injector nozzle and various mixing ratios of blended fuel on engine performances and emissions were investigated. The performance of the CI engine was at peak with a minimum emission using modified 3 holes injector nozzle.