| 摘要 |
PURPOSE:To enable to control the swirl ratio of intake air appropriately, by providing a helical port for feeding swirl air, a volumetric efficiency increasing intake port formed under said helical port for increasing the quantity of intake air, and a means for controlling the quantity of intake air. CONSTITUTION:Intake-air feeding ports 2, 3 supply air from a compressor to a cylinder 1. Here, the port 2 is formed as a helical port, and a high-swirl generating helical wall surface 2a for supplying high-swirl air flow A to the cylinder 1 is formed at an upper portion of the port 2 while swirl-generation reducing wall surface 2b for blowing air flow B straightly to the cylinder 1 is formed at a lower portion of the port 2. On the other hand, the port 3 is formed as a volumetric efficiency increasing intake port, and its opening 3a is formed at the position of a cylinder head 6 where the high-swirl air flow A from the port 2 is branched from the straight air flow B for preventing reverse swirl of air flow. Further, a control valve 4 is provided in the port 3. |
