Fluid responsive vent control valve with peel-away opening action

Reference Number: N 01-05

Inventors: Bergsma, Rudolph; Waldorf, Lindsey E.

USPTO Link: 5605175

Invention Summary

The present invention is a fluid-responsive, high volume vent valve for use in the fuel tank of a vehicle to vent fuel vapor from the tank to a vapor canister. The valve of the present invention provides a positive closing seal for the vent outlet in response to a full fuel level, and in rollover situations, as well as a powerful opening force to break that seal and open the valve when the fuel recedes or the valve returns to a normal attitude.

The above objects are achieved with a hollow vent valve mounted in the wall of a vehicle fuel tank, having a lower portion with a venting inlet in the interior of the tank, and an upper portion with a high volume venting outlet connected to the vapor canister. A float member is mounted in the lower portion of the valve body to ride up and down between a lower open position and an upper closed position in response to liquid fuel level or a rollover situation. The float controls a flexible, ribbon type peel-away valve element associated with the vent outlet to open and close the vent.

The valve element is a flexible, ribbon-like seal connected at one end to the valve body, and at the other end to the float. The closure portion of the valve element conforms to the vent outlet to tightly close it when the float is raised to the closed position. In a first embodiment the vent outlet preferably has a length greater than its width to define a longitudinal lever arm along which the ribbon seal is peeled off. The float and vent outlet are axially offset, allowing the float to pull the ribbon off the vent outlet with no frictional binding effect on the float.

In a second embodiment, which is preferred for onboard vapor recovery, the float and vent outlet are essentially coaxial. The flexible ribbon valve member includes a central valve closure portion, a first end connected to the float on one side of the vent outlet, and a second end connected to the valve body on the opposite side of the vent outlet. The float further includes closure assist structure which engages and helps seal the valve closure portion of the ribbon member against the coaxial vent outlet to a closed position, even under no or low pressure differential conditions. In a further preferred embodiment the vent outlet includes a single large opening with a small roundoff notch, the roundoff notch lying within the operating dimensions of the closure assist structure on the float. As the ribbon element is sequentially presented by the float to close off the vent outlet, an initial shutoff occurs when all but the roundoff notch is closed. Pressure alone is insufficient to seal the roundoff notch, allowing a final roundoff of fuel tank level. Final shutoff occurs only after the fuel level forces the float and its closure assist structure upward to seal the roundoff notch.