Impact of ethanol in ethanol blended gasoline on the spray characteristics of piezo actuated outward-opening injector

Abstract

As ethanol fuel is a very attractive alternative fuel for spark ignition engines, it does make sense to take a closer look into direct injection spark ignition engine with ethanol fuel. In addition, the piezo actuated outward-opening injector has been demonstrated to have high potential for fuel consumption reduction. Thus it does make sense to study the application of ethanol fuels on this new type of injector. In this study, the spray characteristics of piezo actuated outward-opening injector were investigated while applying ethanol blended gasoline with different ethanol concentration (20 %, 50 %, and 85 % ethanol) as well as commercial gasoline by means of injection quantity and injection rate measurement, PDA (phase Doppler anemometer), macroscopic Mie-scattering and shadowgraph techniques. Before these experiments, a specifically fuel delivery system has been developed for this study. A comparative analysis of blended fuels and gasoline sprays regarding injection parameters and spray characteristics is presented. The experimental results show the larger viscosity of ethanol fuel decrease injection quantity and injection rate during main injection stage slightly. Besides, spray front penetration was found be decreased while the increasing of ethanol’s portion. On the other hand, the edge vortex formation was enhanced by ethanol fuel. The Varies of volatility properties among different fuels have impact on spray atomization and vaporization process.