Investigation Into the Deteriorated Performance of Diesel Engine After Prolonged Use of Vegetable Oil

The use of vegetable oil in its original from in diesel engines poses a few challenges especially after prolonged use. In this study, it was found that after 500 hours of cumulative running with crude palm oil (CPO), the maximum power was reduced by about 20% and the minimum brake specific fuel consumption (bsfc) increased by about 26%. Examination of the different parts revealed heavy carbon deposits in the combustion chamber, traces of wear on the piston rings, the plunger and the delivery valve of the injection pump; slight scuffing of the cylinder liner, and uneven spray from the nozzles. The affected parts were installed in a new identical engine one by one to evaluate the performance of each respectively. Tests revealed that the main reason for engine performance deterioration was ‘valve sticking’ contributing about 18% and 23% to the deterioration of maximum power and minimum bsfc respectively.