The air-fuel mixture in the gasoline engines is prepared in-cylinder and out-cylinder. While the mixture in the engine with carburettor (Fig 1) and port fuel injection is prepared out-cylinder, mixture in the gasoline direct injection engines is prepared in-cylinder. In place of PFI (Fig 1) engines where the fuel is injected through the port, in GDI engines (Fig 1), the fuel is injected directly into cylinders at a high pressure