The main air motion in 4-Valve S.I. Engines is tumble , which is helpful for improvingcombustion. In this paper. three-dimensional numerical modeling is used to study the tumblemotion in a 4--Valve S.I. Engine by ALE method. 3-D results show how the tumble isgenerated, developed and broken up. The development of tumble turbulence intensity andthe averaged turbulence intensity in whole cylinder is also obtained. Comparison betweencalculated and experimental results shows they agree each other fairly well, which veriliesthe creditability of the 3-D numerical modeling.
4-Valve S.I. Engine; Tumble motion; Numerical Modeling; ALE method