Effect of hydroxyl (OH) group position in alcohol on performance, emission and combustion characteristics of SI engine

Abstract

Abstract In this research work, an attempt has been made to compare the performance and emission characteristics of n-butanol (n-B), iso-butanol (Iso-B), n-pentanol (P) and benzyl alcohol (Bn) with gasoline at various load conditions in the ratio of 10:90 by volume respectively, in a 2 cylinder SI test engine with MPFI technology. Alcohols were selected based on the position of hydroxyl (OH) group in its molecular structure, OH group was in straight chain for n-butanol and n-pentanol while it was branched chain for iso-butanol and finally OH group was chained with benzene ring for benzyl alcohol. The favorable outcome was that the performance of the fuel blends was noticeably higher than neat gasoline, with Bn10 blend giving greater fuel power at 100% load and P10, Bn10 and iso-B10 giving greater brake thermal efficiency. On the other hand, it was observed that the fuel consumption of n-B10 was higher than gasoline but iso-B10 gave lower fuel consumption comparatively. Considering pollutant emissions, all the blends gave lower HC, CO, & CO2 emissions as compared to neat gasoline, although the NOx emissions increased with increasing loads. Considering both performance and emission characteristics it was finally concluded that benzyl alcohol – gasoline blend was better compared to other blends.