Patent ID: 8286658

Claim:
A tank venting system comprising a flow controller including a flow-control housing formed to include an internal space and an air/vapor flow regulator located in the internal space of the flow-control housing, the flow-control housing also being formed to include a tank port opening into the internal space and a canister port opening into the internal space and being adapted to communicate air and fuel vapor to and from the internal space and a fuel vapor recovery canister associated with the flow controller, and a tank valve system coupled to the tank port foamed in the flow-control housing and adapted to communicate air and fuel vapor to and from the internal space in the flow-control housing and a vapor space in a fuel tank associated with the flow controller, the tank valve system comprising a fluid-conducting passageway communicating with the tank port and the vapor space in the fuel tank and a first roll-over valve configured to provide means in the fluid-conducting passageway for blocking flow of pressurized fuel vapor discharged from the vapor space of the fuel tank through the fluid-conducting passageway and the tank port to the internal space formed in the flow-control housing whenever the first roll-over valve is tilted at least a selected number of degrees from a normal upright position so that fuel vapor from the vapor space of the fuel tank is unable to flow through the fluid-conducting passageway to reach the internal space of the flow-control housing, and wherein the air/vapor flow regulator is configured to provide means for blocking discharge of fuel vapor extant in a portion of the fluid-conducting passageway located between the first roll-over valve and the tank port and pressurized at a magnitude below a predetermined pressure threshold during a fuel tank refueling activity to establish a fuel tank overfill protection system and a fuel tank pressure-relief system so that the vapor space of the fuel tank associated with the flow controller is not vented to the fuel vapor recovery canister associated with the flow controller via the internal space formed in the flow-control housing while the fuel tank is being filled with liquid fuel unless fuel vapor pressure in the fuel tank exceeds a predetermined minimum pressure that is higher than a pressure associated with fuel tank refueling activities and for allowing flow of air and fuel vapor through the internal space formed in the flow-control housing between the canister and tank ports to regulate admission of ambient air from the atmosphere into the fuel tank through the flow-control housing and the fluid-conducting passageway when a vacuum characterized by at least a predetermined negative pressure has developed in the vapor space of the fuel tank associated with the flow controller to establish a fuel tank vacuum-relief system.