Fuel level responsive vapor vent valve

Reference Number: N 01-05

Inventors: Bergsma, Rudolph

USPTO Link: 5062444

Invention Summary

The present invention is a fuel tank vent valve responsive to the level of fuel in the tank. The valve permits the escape of air and fuel vapor from a tank when the fuel cap is removed and closes only when the fuel level reaches its "full" position. The valve is substantially unaffected by the flow of air and fuel vapor out of the tank and will not close prematurely as fuel is being pumped in.

The valve of the present invention comprises a hollow valve body mounted in the interior of the fuel tank, communicating at one end with the upper end of the filler tube of the tank and having at least one radial port formed in the other end to communicate with the tank interior. A shutter is mounted on the valve body, axially slidable between an open position remote from the radial port or ports allowing air and fuel vapor to flow therethrough and out the tank, and a closed position covering the radial port or ports.

The shutter is moved between the open and closed positions by a float axially slidable on the valve body adjacent the shutter. Because the float and shutter can only move axially with respect to the valve body, and because the air and vapor flow through the port or ports is at right angles to the direction of valve movement, the tendency of the valve to close inadvertently in response to the outbound flow of air and vapor flow is substantially eliminated.

In an illustrated embodiment the float comprises an air chamber opening downwardly towards the fuel in the tank, and is made from a material more dense than the fuel. The float can be separate from the shutter or integrally connected thereto, the latter embodiment assuring that the valve is positively opened as the fuel level drops, even if the surface tension of any fuel trapped between the shutter and valve body tends to hold the shutter in the closed position.

In a preferred embodiment the shutter is provided with drainage holes to allow fuel between the valve body and shutter to drain back into the tank.