Impingement characteristics of an early injection gasoline direct injection engine: A numerical study

This article describes the use of a Lagrangian discrete droplet model to evaluate the liquid fuel impingement characteristics on the internal surfaces of an early injection gasoline direct injection engine. This study focuses on fuel impingement on the intake valve and cylinder liner between start of injection and 20° after start of injection using both a single- and a multi-component fuels. The single-component fuel used was iso-octane and the multi-component fuel contained fractions of iso-pentane, iso-octane and n-decane to represent the light, medium and heavy fuel fractions of gasoline, respectively. A detailed description of the impingement and liquid film modelling approach is also provided. Fuel properties, wall surface temperature and droplet Weber number and Laplace number were used to quantify the impingement regime for different fuel fractions and correlated well with the predicted onset of liquid film formation. Evidence of film stripping was seen from the liquid film formed on the side of th...