Performance of a diesel engine using preheated vegetable oil as an alternative fuel

Abstract

In the view of the energy crisis and emission problems, alternative fuels are promising substitute to the conventional petroleum based fuels. Among those, vegetable oils seem to be a promising substitute of diesel fuels. These have the advantage of being geographically widely produced, in a variety of products and are renewable in nature and thereby not adding to the net atmospheric concentrations of green house gas, CO2. However, higher viscosity and low volatility are identified as the main reasons for the unsuitability of vegetable oils as straight diesel fuel substitute. In this study attempts have been made to evaluate the possibility of using vegetable oils as diesel fuel substitute by modifying their properties. Preheating is one of the promising means to change the fuel viscosity to enhance atomization, mixing with air and better combustion. In the present study, experiments are carried out in a diesel engine at three different speeds and different loading conditions using diesel fuel to generate base data and afterwards the experiments were repeated by replacing diesel fuel by preheated soybean at three different temperatures. Various performance parameters are obtained to study the effects of the degree of preheating of vegetable oils on the engine performance at different engine speeds. It is observed that, straight soybean oil (SVO) can be used to substitute diesel fuel in CI engines with very little power and efficiency loss. It is also observed that, with the increase in the preheat temperature of the vegetable oils, the overall engine efficiency increases.