Experimental Investigation in Combustion Characteristics of Ethanol-gasoline Blends for Stratified Charge Engine

The increasing of global energy demand and stringent pollution regulations have promoted research on alternative fuels. In Thailand, ethanol, can be produced from many sources of national agriculture products as renewable fuel, which was strongly promoted by government due to its many merits for use in transportation field. In this study, combustion characteristics of ethanol-gasoline blend (20%, 85%, and 100%) as well as pure gasoline (E0) were investigated by using a swirl-generated constant volume combustion chamber. Flame propagations of different fuel blends were observed by high speed Schlieren photography technique while pressure history data were recorded for detailed combustion analysis. Combustion behavior, combustion duration and rate of pressure rise of all tested fuels were investigated in various swirl intensities and equivalence ratios. In addition, effect of swirl intensities and ethanol concentration on lean misfire limit were also discussed. The results showed that the high concentration of ethanol blend with the high swirl intensity can significantly extended lean misfire limit while lowering combustion variations. Furthermore, combustion duration can be accelerated by increasing the percentage of ethanol in fuel blend. Through this study, a better understanding of stratified charge combustion fuelled with ethanol/gasoline blends can be achieved.