The increasingly stringent regulations in terms of pollutant emissions have lead the automotive industry to concentrate its resources in the research of new methods to improve internal combustion engine’s efficiency while at least keeping the same performance. Particular attention has been given to the development of more precise and efficient fuel injection systems combined with suitable injection strategies. One of the most powerful tools in the investigation of injection and mixture formation process is the 3D-CFD simulation, which can provide a very precise and reliable reproduction of thermo-fluid-dymanical phenomena inside the engine, with consequent savings in time and financial resources related to the not anymore necessary test campaigns.