Effect of higher and lower order alcohol blending with gasoline on performance, emission and combustion characteristics of SI engine

[Display omitted] •Feasibility study of using higher and lower order alcohols in SI engine.•The blend ratio of 90:10 and 80:20 were followed throughout the test.•Combustion and emissions were analyzed using blends of benzyl alcohol and ethanol.•Influence of the gasoline-alcohols blends based on the order of the alcohol. This investigation mainly focuses on the characteristic study on combustion, performance and emission of gasoline blended with lower order alcohol, i.e. ethanol and higher order alcohol, i.e. benzyl alcohol in the ratio of 10% and 20% by volume of the overall quantity. These two alcohols were blended with gasoline and investigated solely to find the comparison between higher and lower order alcohols and thus to identify the optimum blend based on the performance and emission characteristics. The blends were tested in a commercial two-cylinder 624 cc gasoline engine with multi-point fuel injection (MPFI) system and data acquisition capability. The fuel blends were tested at different loads ranging from 20% to 100% with a step size of 20% in ascending sequence. At full load, higher alcohol blend showed an improvement in brake thermal efficiency (BTE) of 32.8% and 33.2% for Bn10 and Bn20, when compared to neat gasoline 29.77% and BTE of lower alcohol registered a slight improvement in comparison to gasoline, i.e. 30.41% and 31.1% for E10 and E20 respectively. HC emissions were reduced to 70 ppm and 57 ppm for lower and higher alcohol blends respectively, which is lower compared to 88 ppm for gasoline. CO and CO2 emissions were reduced with both lower and higher alcohol blends in comparison with neat gasoline. NOx emissions show a reduction nature with alcohol blends when compared to neat gasoline at all the load conditions. It is perceived that based on the performance, emission and combustion characteristics, higher alcohol namely benzyl alcohol blend with gasoline is optimum.