| 摘要 |
PROBLEM TO BE SOLVED: To prevent resonance of a spring mass system under a specific frequency in engine vibration and intake pulsation.SOLUTION: A PCV valve 40 includes: a case 42 having an inflow port 51 and an outflow port 52; a valve element 60 reciprocatably disposed in the case 42; and a coil spring 74 for biasing the valve element 60 to an inflow 51 side. A measuring portion 44 is disposed in the case 42, a measuring face 62 of the valve element 60 inserted into the measuring portion 44 has a tapered face portion 65 between a small-diameter face portion 63 at a tip side and a large-diameter face portion 64 at a basic end side, and a flow rate of a fluid flowing in a clearance gap 70 between the measuring portion 44 of the case 42 and the measuring face 62 of the valve element 60 is controlled by moving the valve element 60 according to pressure difference between an inflow-side pressure and an outflow-side pressure. The coil spring 74 is a cylindrical irregular pitch coil spring having a nonlinear characteristic in which a spring constant is increased in stages in accordance with increase of a compression amount. |
