| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that, in a conventional intake system, since a valve of a tumble control valve cannot be held stably at a prescribed intermediate position corresponding to an operation situation of an engine, desired tumble performance cannot be obtained and fuel consumption or emission enhancement effects are liable to be reduced.SOLUTION: A first sliding force application mechanism 6 is composed of a pair of first friction materials 51 which are brought into contact with an outer circumferential surface of a protrusion 31 in a valve shaft 3 of a tumble control valve in a slidable manner, and a pair of first springs 52 which generate elastic forces for energizing the first friction materials 51 to press them to the outer circumferential surface of the protrusion 31 in the valve shaft 3. By providing such a first sliding force application mechanism 6, a sliding force (Fv) having prescribed elastic contact pressure can be applied to the valve shaft 3. Thus, a valve 2 or the valve shaft 3 can be held stably with high positional accuracy, thereby improving reliability for the position holding control of the tumble control valve. |
