CFD optimization for GDI spray model tuning and enhancement of engine performance

Coupling a 3D Computational Fluid Dynamics (CFD) tool with a rigorous method of decision making is
becoming indispensable in the design process of complex systems, as internal combustion engines.
CFD based optimization (CFD-O) is here carried out on a single cylinder, four-valve, four-stroke gasoline
direct injection (GDI) engine, to enhance mixture formation under stratified charge operation, hence to
choose between the single or double injection strategy maximizing the engine power output. A 3D engine
model is coupled with the Simplex algorithm to find the optimal synchronization of both injection and
spark timing within the working cycle.
CFD-O is also addressed to perform the validation of the gasoline spray model, that otherwise reveals
tedious and time-consuming. The Simplex algorithm is used to tune the constants entering a model
developed by authors, as applied to three different high pressure GDI injectors, preliminary experimentally
characterized.
Fully automatic procedures are assessed to be exploited in the phase of engine design, whose contribution
may be of great importance to reduce development costs and time-to-market of new technologies.