The study of cyclic variability at a n-butanol spark ignition engine fueled

Abstract

Alcohols such as ethanol, methanol and butanol have gained more attraction in recent years in the use of alternative fuels at the internal combustion engines (ICE) because of their good combustion properties. The use of the butanol-gasoline blends can lead to a decrease in greenhouse gases (CO2) and pollutants such as unburnt hydrocarbons (HC), carbon monoxide (CO) but may increase nitrogen oxides (NOx). An experimental study carried out on a spark ignition engine fueled with a n-butanol-gasoline blend (10% vol. butanol - 90% vol. gasoline) at an engine load χ=55%, speed of n=2500 rpm and different air excess ratios (λ). The objective of this paper is to determine the effects of n-butanol on combustion, specifically on the cyclic variability. So, the COV values for maximum pressure, indicated mean effective pressure and angles of mass fraction burned -10%, 50% and 90%- are presented The engine fueling with butanol-gasoline blend engine leads to the decrease of the cyclic variability and the COV values don’t exceed the recommended value. A great advantage of n-butanol use is the increase of the thermal efficiency due to the stable engine operation and at lean mixtures.