| 摘要 |
A valve controlling a fuel tank pressure is disposed in a passage connecting the fuel tank and a canister that communicates with atmosphere. The control valve includes a first valve for introducing an atmospheric pressure into the fuel tank when the fuel tank pressure becomes negative and a second valve for releasing an excessively high pressure in the fuel tank. The first valve opens when the fuel tank pressure drops below a predetermined level and closes again when the fuel tank pressure is recovered. To prevent a vibrating operation of the first valve between its open and closed positions, the closing operation of the once opened valve is delayed by an orifice formed through a diaphragm of the valve. The orifice alleviates a quick change of the pressure applied to one surface of the valve. A magnet to restrict the quick movement of the valve may be used in place of the orifice. Preferably, an electromagnetic driver for forcibly opening the first valve, irrespective of the fuel tank pressure, is connected to the first valve.
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