Spray properties of alternative fuels: A comparative analysis of ethanol–gasoline blends and gasoline

Ethanol is an attracted alternative fuel and ethanol–gasoline blends can be used as fuel in order to substitute some part of gasoline in engine applications. In this study, the spray properties of different blends of ethanol–gasoline (25%, 50%, 75% and 100% ethanol) as well as pure gasoline are investigated under various ambient conditions by means of high-speed schlieren photography technique. A comparative analysis of blended fuels and gasoline sprays is also presented. The experimental results show that when adopting fuel blends with variable ethanol–gasoline fractions in the swirl-type injector sprays, the spray developing patterns are not significantly changed. In the case of low ambient pressure, the main spray tip penetration decreases and the spray angle increases with the increase of ethanol fraction. Under the elevated ambient pressure condition, the difference of spray penetration amongst the blends shows unconspicuous, meanwhile the spray angle of all test fuels keeps almost constant in the fully developed stage except that the spray of pure gasoline shows a larger cone angle in the beginning of injection period.