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

Reference Number: N 01-05

Inventors: Bergsma, Rudolph; Waldorf, Lindsey E.

USPTO Link: 5313977

Invention Summary

The present invention is a fluid-responsive, high volume rollover 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 fuel surge, and in rollover situations, as well as a powerful opening force to break that seal and open the valve when the fuel surge 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 therein between a lower open position, and an upper closed position in response to liquid fuel surges or a rollover situation. The float controls a peel-away valve element associated with the vent outlet to open and close the vent.

The valve element generally includes a lever arm portion connected to the float. A closure portion of the valve element conforms to the vent outlet to tightly close it when the float is raised to the closed position. The vent outlet and the float can be axially offset within the valve body to maximize the length of the lever arm. The opening force applied to the valve element when the float drops is accordingly amplified by the mechanical advantage obtained with the long lever arm.

In one embodiment, the float provides a "hammer claw" opening mechanism. The float includes structure to peel the valve element off the vent outlet in a three-step "peel, lock, translate" motion in which a lever-type opening moment is applied to initially peel and break the seal between the valve element and the vent outlet, the valve element is locked to the float, and the float pulls the valve element completely free in an axial direction. In an illustrative version of this embodiment, the lever arm portion of the valve element is slidingly connected to an axial guide post projecting from the upper surface of the float. The upward travel of the valve element along the guide post is limited by two contact points of varying height, the lowest of which first engages the valve element as the float drops to apply a pivotal opening moment which breaks the seal between valve element and vent outlet. Contact with the second contact point ends the pivotal peel and locks the valve element relative to the float for subsequent axial translation to pull it completely free.

In one form the two contact points are embodied in the upper and lower edges of an angled flange atop the guide post. The post can be slightly curved to allow a smooth pivot of the valve element between the initial peel or break and subsequent lock up and axial translation.

In another embodiment of the invention, a compound lever arrangement is utilized to increase the mechanical opening advantage without altering the dimensions of the valve to accommodate a longer lever arm. In a third embodiment of the invention, a compound pulley arrangement is provided to increase the mechanical opening advantage, also without having to substantially increase the dimensions of the valve. These structures create powerful moments with which to peel the valve element off the vent outlet and open the valve against the tank/canister pressure differential acting on the relatively large surface area of the valve element.

In a fourth embodiment 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. The valve vent outlet has a length greater than its width to define a longitudinal lever arm along which the ribbon seal is peeled off. In this version the vent outlet itself defines two pivot points about which the ribbon seal is levered at two different stages in the opening process. A first pivot point defines a first lever arm and opening moment sufficient to initially break the seal between the ribbon valve element and the vent outlet, while the second pivot point defines a subsequent longer lever arm through which the float acts to finish the opening of the vent outlet.

In all embodiments maximum opening force is applied to achieve the initial break in the seal between the valve element and the vent outlet.

The valve can include gravity-operated rollover structure associated with the float to force the float to a closed position when the vehicle is tilted or rolled over. In a preferred form, however, the float itself is of a buoyancy which permits it to respond rapidly to liquid fuel surge and rollover orientation to close the valve, assisted by a light bias spring to provide the proper mass balance.