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Abstract
In the present time, the human is facing two essential problems
regarding engine fuels. These problems are the depletion and the
environmental pollution of the fossil oil. Vegetable oils after some
chemical treatments may be used as an alternative to solve partially these
problems, since these oils are renewable and environmental friendly. The
extracted biofuel from vegetable oils is considered as a renewable
alternative diesel engine fuel. The present work aims to study the engine
behavior when using Waste Vegetable Oils (WVOS). For this purpose,
five blends[B5, B10, B20, B30 and B40] of Waste Palm Kernel Oil
(WPKO) and three blends [B20, B30 and B40] of Waste Sunflower Oil
(WSFO) with Diesel Fuel (DF) are prepared and used as a fuel in a direct
injection diesel engine. Because of the great effect of the fuel viscosity
on atomization process and combustion, the WPKO and WSFO are
preheated to approach diesel fuel viscosity. For this purpose the effect of
temperature on the viscosity of WPKO and WSFO is addressed. The
current study proves that, using fuel blends (B5-WPKO, B10-WPKO and
B20-WPKO) lead to an increase in the Brake Thermal Efficiency (BTE)
and decrease in Brake Specific Fuel Consumption (BSFC) compared
with that of DF at different loads. B30-WSFO blend contributes to
increase the BTE compared with that of DF and no significant change is
noticed in BSFC. When heating blends, the BTE increases and BSFC
decreases compared with that at normal conditions. Smoke density
percentages during each of the WVO blends operations were greater
than that of DF. When heating blends, the smoke density decreases
compared with that at normal conditions. Moreover, the present study
reveals that, WVOS can be used as an alternative fuel in diesel engine
without any major modifications. A mathematical model is developed to simulate the engine behavior
when running with WSFO blends as biofuel. The model is used as a tool
to predict the engine performance at wide range of fuel blends. The result
show fair agreement with experimental data.