Fluid-responsive vent control valve with peel-away opening action

摘要

The present invention comprises a rollover vent valve for mounting on a vehicle fuel tank to selectively vent fuel vapor from the fuel tank to a vapor trap such as a carbon canister. The valve includes a liquid fuel responsive control element connected to a valve element via lever arm structure to move the valve element between open and closed venting positions on a valve seat. The mechanical opening advantage obtained with the lever arm structure provides for a powerful peel-away action to ensure opening of the valve despite a tank/canister pressure differential acting to maintain the valve element in the closed position. In one embodiment the lever arm structure includes a hammer-claw mechanism to provide an initial pivotal opening force using the maximum potential of the lever arm, and a subsequent rectilinear opening force.