Spray characteristics of ethanol-gasoline blends from an asymmetric multi-hole injector of DISI engines

Ethanol is an attracted alternative fuel, while ethanol-gasoline blends can be a way for substituting some part of gasoline. To apply ethanol or ethanol-gasoline blends to DISI engines, the spray characteristics of various blends of the ethanol and gasoline (25%, 50%, 75% and 100% ethanol) as well as pure gasoline were investigated by means of high-speed shadow photography technique, employing a multi-hole DISI engine injector with asymmetrical nozzle-hole arrangement. A comparative analysis of fuel concentrations of ethanol-gasoline blends and pure gasoline was also presented. The results show that the spray developing patterns were slightly changed with increasing ethanol fraction in gasoline. Under low ambient pressure condition, the spray tip penetration decreased and the spray angle increased with increasing ethanol fraction in gasoline. Under the elevated ambient pressure condition, the spray tip penetration increased and the spray cone angle decreased with the more ethanol fraction in gasoline, meanwhile the spray angles of all test fuels tended to stay constant in the fully developed stage.