| 摘要 |
A roll-over valve is provided for use in a vehicle fuel system having an outlet for discharging fuel vapor. The roll-over valve includes a hollow valve member that terminates in a distal tip. A roll-over ball is provided for moving the distal tip from an outlet-opening position to an outlet-closing position in response to tilting of the hollow valve member during vehicle rollover conditions. Weighted members in the form of weighted balls are disposed within the hollow valve member to counteract the lifting force that may be imposed upon the hollow valve member by the formation of a low pressure area over the distal tip due to high flow rates of vapor over the tip. The weighted balls aid in preventing the valve member from being urged upwardly to prematurely seal the outlet. The hollow valve member is formed to include a sealed chamber so that a buoyant force is created when fuel enters the valve. The buoyant force created by the sealed chamber when exposed to fuel is sufficient to overcome the oppositely directed force exerted by the weighted balls to permit the hollow valve member to move normally when urged upwardly by the actuating ball in response to tilting of the valve member during vehicle rollover conditions.
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