In-Cylinder Gas Motion during Intake-Stroke in a DI Gasoline Engine.

Abstract

A key technology to realize the gasoline direct injection combustion is to control the in-cylinder gas motion. The effect of the shroud attached on intake valves and the cam profile for intake valves on the flow characteristics such as the swirl and tumble are examined from a theoretical viewpoint. As a result, it is found that the shroud affects not only the swirl flow but also tumble flow, and that the spatial stratification of swirl intensity in the axial direction, which can control the in-cylinder gas motion during the compression stroke, is difficult only by a modification of the valve timing