Fuel vapor vent system and low permeation vacuum operated shut-off valve therefor
AssigneeEaton Corporation
InventorRobert P. Benjey
Life of this patent
Estimating the term…
Abstract
A vacuum operated flow control valve is disposed in the vapor vent line from a fuel tank to a vapor storage canister connected also to the engine air inlet. The valve has a diaphragm operator of low permeability which is biased normally open to permit fuel vapor to flow from the tank to the canister during engine shutdown. Upon engine startup a vacuum is drawn in the canister and the flow control valve which closes preventing vacuum being drawn in the tank thereby preventing tank collapse. During engine shutdown, if an ambient temperature drop creates a vacuum in the tank, the flow control valve closes; however, an emergency umbrella relief valve opens permitting reverse flow of vapor from the canister to the tank preventing excessive vacuum in the tank.
Claims20
A vacuum operated shut-off valve for use in a fuel tank vapor vent line comprising:
- (a) a valve body having an inlet adapted to receive fuel vapor from the tank and an outlet for connection to a vapor storage reservoir, said body having a valving chamber communicating with said inlet and outlet;
- (b) a pressure responsive member forming a portion of the wall of said valving chamber and operable in response to a pressure differential there across to move from a position permitting to a position preventing communication between said inlet and outlet;
- and,
- (c) means defining a vacuum chamber communicating with one side of said pressure responsive member opposite a side forming a portion of the wall of said valving chamber, said vacuum chamber having a vacuum signal port therein adapted for connection to a source of vacuum, wherein said pressure responsive member is formed of polymeric material having a relatively low fuel vapor permeability.
A system for controlling fuel tank vapor emission comprising:
- (a) a valve body having an inlet connected for receiving fuel vapor from the tank and an outlet with a valving chamber communicating with the inlet and outlet;
- (b) storage device connected to said outlet and the air inlet of an engine;
- (c) a pressure responsive member forming a moveable wall portion of the pressure chamber including a surface impervious to fuel vapor and operable for movement between a first position preventing and a second position permitting flow between said inlet and outlet wherein one side of said pressure responsive means opposite said chamber is vented to the atmosphere.
A method of controlling vapor emissions from a fuel tank, comprising:
- (a) connecting a vapor storage device to a fuel tank vapor vent and disposing a pressure responsive valve in the line between said tank and said device;
- (b) connecting said device to the air inlet of a fuel burning engine;
- (c) disposing a flexible diaphragm of material having a relatively low fuel vapor permeability in said valve and biasing said diaphragm to a position permitting flow through said valve, and upon the occurrence of a vacuum in one of said storage device and said tank creating a differential pressure on said pressure responsive member and closing said valve.
Dependencies are inferred from the claim text.