Fuel vapor storage and recovery apparatus and method

A fuel vapor storage and recovery apparatus for a motor vehicle having a fuel tank with a fuel vapor/air mixture therein above a liquid fuel in the fuel tank comprising:

• a vapor storage canister having a fuel vapor adsorbent material therein and an atmospheric vent port,
• a control valve selectively operable to open and close the atmospheric vent port,
• a first conduit means operative to conduct a fraction of the fuel vapor/air mixture from the fuel tank to the vapor storage canister when the atmospheric vent port is open so that a fuel vapor fraction of the fuel vapor/air mixture is adsorbed on the adsorbent material and an air fraction of the fuel vapor/air mixture is expelled to the atmosphere through the open atmospheric vent port,
• a heater means operative when the atmospheric vent port is closed to heat the adsorbent material to a purge temperature above an ambient temperature in the fuel tank at which purge temperature the adsorbed fuel vapor fraction of the fuel vapor/air mixture vaporizes and fills the vapor storage canister with hot fuel vapor at a pressure above the pressure of the fuel vapor/air mixture in the fuel tank, and
• a second conduit means operative to conduct the hot fuel vapor from the vapor storage canister to the fuel tank wherein the hot fuel vapor condenses to liquid fuel at the ambient temperature in the fuel tank.

A fuel vapor storage and recovery apparatus for a motor vehicle having a fuel tank with a fuel vapor/air mixture therein above a liquid fuel in the fuel tank comprising:

• a vapor storage canister having a honeycomb therein with a coating of a fuel vapor adsorbent material thereon and an atmospheric vent port,
• a control valve selectively operable to open and close the atmospheric vent port,
• a vapor/purge conduit operative to conduct a fraction of the fuel vapor/air mixture from the fuel tank to the vapor storage canister when the atmospheric vent port is open so that a fuel vapor fraction of the fuel vapor/air mixture is adsorbed on the adsorbent material and an air fraction of the fuel vapor/air mixture is expelled to the atmosphere through the open atmospheric vent port,
• an electrically conductive substrate between the honeycomb and the coating of fuel vapor adsorbent material thereon,
• a source of electrical energy, and
• a switch operative to selectively connect the source of electrical energy to the electrically conductive substrate so that the electrically conductive substrate defines a heater operative when the atmospheric vent port is closed to heat the coating of adsorbent material to a purge temperature above an ambient temperature in the fuel tank at which purge temperature the adsorbed fuel vapor fraction of the fuel vapor/air mixture vaporizes and fills the vapor storage canister with hot fuel vapor at a pressure above the pressure of the fuel vapor/air mixture in the fuel tank,
• the hot fuel vapor being conducted through the vapor/purge conduit to the fuel tank wherein the hot fuel vapor condenses to liquid fuel at the ambient temperature in the fuel tank.