| 摘要 |
PURPOSE:To prevent weakening of a swirl flow due to the directivity of an intake flow stirred and deenergized, by providing a protruding wall in a secondary intake air passage in the vicinity of an intake valve seat and a recessed groove communicated to a communication opening of a primary intake air passage along said protruding wall. CONSTITUTION:In a range of low and intermediate loads, primary side intake air flows out in the direction of generating a swirl flow from a communication opening 18 via a primary intake air passage 16, here a point end 28 of a protruding wall 24 is provided in the vicinity of an intake valve stem 12, and the primary side intake air flows into a combustion chamber 8 via only one side of the stem 12 to cause a strong swirl. Here a reverse flow of intake air is generated in a secondary intake air passage 20, however, the reversely flowing intake air in a secondary side, advancing in the passage 20 of large contour, tends to flow into the chamber 8 at a gentle speed further without having directivity. However, similarly to the primary intake air flow at this time, the intake air in the secondary side is guided by the wall 24 having the tangential directivity of a cylinder to flow in through only the one side of the stem 12 and into the chamber 8. |
