Study of liquid and vapour phases of a GDI spray

Gasoline direct injection (GDI) systems have become dominant in passenger cars due to their flexibility in managing and advantages in the fuel economy. With the increasingly stringent emissions regulations and concurrent requirements for enhanced engine thermal efficiency, a comprehensive characterization of the fuel spray behavior has become essential. Characteristics of free and impingement spray fueled with iso-octane were investigated by a hybrid Mie scattering and schlieren optical technique with a direct injection gasoline injector, from the Engine Combustion Network (ECN). The experiments provided the spatial distribution and time-resolved evolution of the free, as well as the post-impingement spray characteristics under various operating conditions. A customized algorithm, able to catch the contours of both liquid and vapour/atomized phase, was used to extract the diffusion and evaporation parameters that characterized the fuel spray. Aim of this study is a detailed understanding of a GDI spray evolution under engine-like conditions, by studying both the liquid and the vapour phases as the ambient and injection conditions vary in a controlled environment.