An injector specific analytic-phenomenological spray propagation model for the application-oriented simulation of direct injection SI engines

Spray-guided combustion processes for gasoline direct injection offer a great fuel saving potential but also put high demands on mixture formation quality. Systematic optimization by means of experiments or three-dimensional computational fluid dynamics (3-D CFD) requires tremendous effort. As an alternative, this paper presents an application-oriented, zero-dimensional (0-D) simulation model. A comparison with laser-induced exciplex fluorescence (LIEF) tomography measurements revealed good agreement between simulation and experiment. The proposed spray propagation model precisely captures the injector-specific spray penetration, volume propagation, and air entrainment rate of an annular-orifice injector and a multihole injector. The vaporization rate and the mean air/fuel-ratio as the key measure of mixture formation quality are correctly reproduced. The presented model is employed to optimize the injector mass flow rate with respect to a minimum mixture formation time.