Walbro Corporation

Timothy P Neal

Mark R Johansen

George H Bucci

Jason J St Pierre

A vehicle on board system for recovering fuel vapors from the fuel tank both during filling of the fuel tank with volatile hydrocarbon liquid fuel and operation of the vehicle engine. A control unit in the fuel tank has a valve assembly actuated by a float to control the flow of fuel vapors from the top of the tank into a receiving canister with activated charcoal for absorbing the fuel vapors which can be purged from the canister by operation of the engine. The valve assembly has a valve seat, a flexible elastomeric closure received on a pivotally mounted carrier plate movable to open and closed positions relative to the seat, and a stripper plate encompassing the seat, overlying the closure and pivotally movable by the float to disengage the closure from the seat to open the valve. Preferably, a pad on the stripper plate bears on only a portion of the flexible closure during initial opening of the valve to thereby decrease the force required to initially open the valve and increase the sensitivity and responseness of the valve assembly. Preferably, to substantially prevent any liquid fuel from passing through the valve assembly while it is open, a depending tube encircles the valve assembly and the float is slidably received in the tube with a relatively close fit to prevent fuel sloshing in the tank which enters the tube from being forced past the float and into the open valve assembly. Preferably, the passage for permitting fuel vapors to flow to the open valve assembly communicates with the tank at a position generally vertically below the valve assembly and preferably an intermediate portion of the passage is disposed generally vertically above the valve assembly and preferably above the fuel tank.

Control valve and system for fuel vapor recovery

An improved filler neck for a fuel inlet of a vehicle fuel tank has a bend communicating with converging and diverging portions which control the flow of fuel through the filler neck to ensure that fuel flows through and downstream of the bend without backing up in the filler neck and actuating an automatic shutoff device of a refueling nozzle received in the filler neck. The filler neck also preferably has a bypass fuel passage through which fuel flows upstream through the filler neck and out to the atmosphere if a predetermined maximum pressure is exceeded within the fuel tank to limit the maximum pressure within the fuel tank and prevent it from being damaged or rupturing. Several angled ribs in the filler neck housing guide the refueling nozzle for proper positioning within the filler neck. Other ribs also provide gaps between the refueling nozzle and the filler neck housing to prevent the refueling nozzle from sealing the filler neck inlet. Slots at the nozzle interface provide a vent area to prevent a vacuum from being generated in the filler neck even when used with a refueling nozzle designed to provide a vapor tight seal at the refueling inlet to prevent liquid fuel from being drawn upstream through the filler neck and thereby prematurely activating the automatic shutoff device of the refueling nozzle.

Fuel tank filler neck with bypass passage

A filler neck of a fuel tank extends from the gas cap to the interior of a fuel tank, and a fill valve insert is positioned adjacent the tank-interior end of the filler neck in a tank/neck coupler construction. The insert carries a flexible valve to close the interior end of the filler neck, and the valve is designed and mounted both to flex open and bodily move downstream to both open and rapidly enlarge the valve opened passageway in response to rapid inflow of fuel to the tank, and to return and revert to a closed position upon cessation of fuel inflow. The fill valve insert is positively positioned and held in the interior of a threaded spout on the fuel tank and is retained and sealed against the filler pipe by a threaded collar screwed onto the threaded spout. In the event the filler neck is pulled loose from its frictional clamp fit in the tank/spout collar by vehicle crash forces, the tank spout will remain closed and sealed by the valve insert remaining retained by the collar in the spout to thereby prevent fuel spillage from the tank.

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Harwington, CT, United States of America

Timothy P Neal