Patent attributes
A vent apparatus is opened to allow free flow of fuel vapor from a vehicle fuel tank through the vent apparatus to a fuel vapor recovery canister during tank refueling until a predetermined level of liquid fuel is reached in the vent apparatus. Once refueling has been completed, the vent apparatus is closed to block or limit further flow of liquid fuel to the vent apparatus. At the same time, fuel vapor discharge passageways in the vent apparatus that had been closed once the fuel tank had been filled to a predetermined capacity with liquid fuel are reopened so that fuel vapor can flow freely from the fuel tank to the canister even though the volume or height of liquid fuel in the fuel tank has not decreased since the tank was filled during refueling.
