Tthe flow phenomena in gasoline engines including the air motion, the turbulent premixed-combustion, and the two-phase flows of fuel, are explained by using the numeriacal models. First, the temporal-dependent feature of turbulent flow is analyzed by the visualizations of computation and experiment. Then, it is shown that turbulence plays an important role to the stable combustion and the increase of combustion speed, which are important for realizing lean-buring or low-emission engines. Finally, the fuel-droplets motion is analyzed. The breakup process of droplets due to the wall impingement and the air motion are depicted.
