Influence of Fuel Injection on Gasoline Engine Performance

Because of the most common method of preparing the fuel-air mixture for gasolinefueled engines is port fuel injection (PFI). For reducing the wall-film entering the cylinder in liquid phase, the phenomena of wall-film entering the cylinder in liquid phase should be at minimum lever or be avoided. So the first thing for learning the wall-film is to detect the way of the wallfilm entering the cylinder. Therefore, the way of the wall-film enter the cylinder in liquid phase is detected by changing the temperature of the wall-film location and time for wall-film evaporated. Then the way is validated by experiment test bed and it is improved that the way is feasible. At the end the influence of injection timing and fuel ratio on engine performance is studied based on the test bed.The results show that regardless of the expansion stroke or the intake stroke fuel injection the injection timing delay will decrese the engine power and make emission deterioration meanwhile the twice fuel injection can improve the fuel film evaporation resulting of high-speed airflow of intake charge.