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.
