| 摘要 |
PURPOSE:To enable to open a restriction valve in a stable manner, by providing a throttle on the upstream side of the restriction valve in an apparatus having a restriction valve which is opened when the suction vacuum becomes higher than a prescribed value in an air supply passage by-passing a throttle valve. CONSTITUTION:A vacuum controlling apparatus 10 is disposed in an air supply passage 21 by-passing a throttle valve 7, and it consists of a support member 16 having many holes 18 and a restriction valve 15 urged onto a seat portion 23 of a adjust screw 22 by a coil spring 14 the lower end of which is supported by the support member 16. Here, an orifice 26 having a bore diameter smaller than that of the seat portion 23 is formed in the air passage at the portion thereof located slightly upwards of the seat portion 23 of the adjust screw 22. With such an arrangement, it is enabled to swirl the air flow at the time when the restriction valve begins to open, to make the pressure acted to the restriction valve 15 uniform and to thereby stabilize the valve opening movement of the restriction valve 15. |
