Effect of the Intake Valve Lift on Tumble Flow and Combustion Characteristics in an S.I. Engine

摘要

The in-cylinder flow was measured by PIV to investigate the effect of the intake valve lift and the shape of combustion chamber around the intake valve. When the valve lift was decreased, the flow of a reverse-tumble direction was relatively increased and the tumble ratio was decreased. If the guide wall is installed in the valve surrounding under a low valve lift operation, the strong tumble flow has been able to generate and to improve the mixing and combustion.