| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an intake passage structure of an internal combustion engine stably creating a swirling air flow in a combustion chamber by an airflow control valve disposed before a downstream side connection of the intake passage. <P>SOLUTION: The intake passage structure 100A of the internal combustion engine has the airflow control valve 1 for forming a tumble flow T in the combustion chamber 54 before a downstream side opening of the intake manifold passage. A surface S not smooth is formed on a downstream side portion of a flow path in an upper part of the wall surface of the intake manifold passage, which forms the flow path together with the airflow control valve 1 when the airflow control valve 1 is closed. The surface S not smooth is formed in a direction almost perpendicular to a flow of intake air flowing through the flow path by grooves 21A extending in a range corresponding to the intake air flow. The intake air drifted by the airflow control valve 1 is forcibly separated when passing the not-smooth surface S formed by the grooves 21A and the separated intake air is inhibited from rapidly adhering to the wall surface of an intake port 10 again. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
