Abstract
A physical model for the hollow-cone spray injected from a swirl injector has been proposed. It has been found that the spray model can predict the shape and Sauter mean diameter of the spray considerably well. Furthermore, a physical model for the fan spray injected from a slit injector has been contrived. Using the authors GTT code with these spray models, the behavior of the fuel sprays injected from a swirl injector or a slit injector in the last period of compression stroke in typical three-types of gasoline direct-injection engines has been numerically simulated, and the process of mixture formation has been made clear.