| 摘要 |
PROBLEM TO BE SOLVED: To increase a purge flow rate by preventing a choking by increasing a suction manifold negative pressure, in a fuel vaporization gas management valve(VMV). SOLUTION: A VMV has an electric ventilation valve to control the atmosphere bleed flow rate to a negative pressure signal pressure chamber 108. The pressure of the signal pressure chamber 108 controls the differential pressure operating to both surfaces of a diaphragm which moves a valve member to regulate the fuel vaporization gas purge flow rate from a canister to a suction manifold. The negative pressure operates to the signal pressure chamber 108 through the limit passage 119 of a connector 116 which prevents the choking of the sound speed flowing. In one embodiment, two orifices 112 and 120 are provided by keeping an interval in series hydraulically. In another embodiment, laminar flow passages provided in parallel hydraulically are provided to an element consisting of a porous filter which is formed of a fibrous material or a sintered metal, favorably. Alternatively, a laminar flow element is provided in series with a flow rate limit orifice hydraulically.
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