To minimize a hysteresis difference in terms of flow rate characteristics when a negative pressure is changed from a high negative pressure region to a middle negative pressure region.
A plurality recessed parts 20... are formed along the outer peripheral edge of the end face on one side of a valve part 18 possessed by a valve element 16 with which one end of a coil spring 9 makes contact, and a flow-through port for blow-by gas is formed in a contact part between one end of the coil spring 9 and a valve part. Through the presence of the through- flow port, the adjoining windings of the coil spring 9 are adhered to each other and when a valve element reaches a movement limit in the direction of an outflow port 3, formation of a new throttle in a spot situated upper stream from a flow rate control part 5 is prevented. A negative pressure on the outflow port 3 side is increased to a high negative pressure and a reduction amount of a control flow rate of blow-by gas after a valve element 16 reaches a movement limit in the direction of the outflow port 3 is decreased. Simultaneously, a hysteresis difference in terms of flow rate characteristics produced when a negative pressure is changed from a high negative pressure state to a middle negative pressure state is decreased.
NAKAZAWA MINEYUKI
KUSABA MASATOSHI
NISSAN MOTOR
Next Patent: EXHAUST GAS DEVICE FOR MOTIVE POWER VEHICLE AND MOTIVE POWER VEHICLE