| 摘要 |
PURPOSE:To achieve good combustion performance under wide load area by providing an auxiliary intake path branched from the intake path in the upstream of a gate valve and communicated to one intake port while delaying the opening timing of intake valve of one intake port. CONSTITUTION:Under low load area where a gate valve 18 will close, all of the intake air passing through main intake path 11 is led through an opening 19 to an auxiliary intake path 20 while fed through an opening 21 into a combustion chamber 4. Since the cross section of said path 20 is set lower than those of respective branch intake path 15, 16, relatively high flow speed can be achieved even under low load where the intake air flow is low. While second intake valve for opening/closing second intake port 6 is set to open slightly earlier than first intake valve for opening/closing first intake port 5. Consequently, variation of the strength of swirl of intake air due to the variation of load can be suppressed to achieve good combustion performance. |
