| 摘要 |
PURPOSE:To improve filling efficiency by making both intake valves the same area and balancing intake streams when both passages are opened in an engine having two intake valves for each cylinder. CONSTITUTION:One cylinder has two intake valves: a main intake valve 11 and a sub-intake valve 13; each intake valve is communicated to a main intake port 5 and a sub-intake port 7; and a cutoff valve 21 preventing an intake stream to the sub-intake port 7 side is provided at a junction section upstream both intake ports. At a low load, the cutoff valve 21 prevents the intake stream to the sub-intake port 7 side, thereby almost all the intake stream is sucked into the cylinder via the opening section of the main intake valve 11 provided to form a swirl from the main intake port 5. At a high load, the cutoff valve 21 is opened and the sub-intake port side also sucks the intake stream, and since cross-sectional areas of both intake valves 11, 13 are equal, almost the same intake stream is sucked through both valves. |
