Evaporative emissions of fuel vapor from a vehicle having an internal combustion engine occur principally due to venting of the fuel tank of the vehicle. When the vehicle is parked, diurnal changes in temperature or pressure of the ambient atmosphere cause air to waft into and out of the fuel tank. Some of the fuel inevitably evaporates into the air within the tank and thus takes the form of a vapor. If the air emitted from the fuel tank were allowed to flow untreated into the atmosphere, it would inevitably carry with it this fuel vapor. The fuel vapor, however, is a pollutant. For that reason, federal and state governments have imposed increasingly strict regulations over the years governing how much fuel vapor may be emitted from the fuel system of a vehicle.
One approach that automobile manufacturers have long employed to reduce the amount of fuel vapor that a vehicle emits to the atmosphere involves the use of a storage canister. In this approach, a tube, often referred to as a “tank tube,” is used to connect the air space in the fuel tank to the storage canister. Inside the storage canister is contained a sorbent material, typically activated carbon, whose properties enable it to adsorb the fuel vapor. Consequently, when air flows out of the tank, the tank tube carries it to the storage canister wherein the fuel vapor is adsorbed into the sorbent material There the fuel vapors are temporarily stored so that they can be burned later in the engine rather than being vented to the atmosphere when the engine is not operating. Due to increasingly stringent air quality standards, improvements are always sought in the art.