Optimal control strategies for low fuel consuption in a GDI engine under single andl multiple injection

The optimization of the mixture formation process in a GDI (gasoline direct injection) engine equipped with high-pressure seven-hole injector is pursued by coupling a 3D model of the in-cylinder processes with an optimization tool. The 3D model of the in-cylinder processes is developed on the ground of experimental data. Injection strategies, as preliminary experimentally characterized on a Bosch tube, are considered as occurring or in a single event or in multiple events. The advantages of splitting injection into four parts are discussed. Optimal injection strategies and time of spark advance are chosen in order to reduce the gasoline consuption, hence to increase the engine energy efficiency. The effect of the mixture formation precess on the formation of the main pollutants are also discussed.