205 Analytical Study of Wall Impingement Behavior in Direct Injection Gasoline Spray

Abstract

In the case of direct injection gasoline engines, the injected fuel spray impinges on a piston head for stratification combustion, consequently, the spray-wall interaction process leads to the generation of unburned hydrocarbons and combustion chamber deposit. Therefore, it is very important to analyze the fuel behavior during the spray-wall interaction. As the first step, small non-dispersed droplet impinges on a hot wall that simplify fuel spray impinge on a hot wall. The film formation process and breakup-dispersion process was observed by means of high-speed video camera. As the second step, for impinging spray, the behavior of droplet images was taken by laser sheet scattering. As a result, the breakup pattern of the impinged droplet is classified into 7 types. The film formation and breakup-dispersion process is predicted by impingement angle, Weber number and surface superheat degree. Spray-wall interaction process of injected fuel spray is affected by surface superheat degree.