초록 ▼

An onboard vapor recovery system for a vehicle fuel system having a fuel tank, a filler neck dynamically sealed by high pressure fuel flow from a filler nozzle, and a vapor recovery apparatus such as a carbon canister. The system includes a liquid level operated control valve which shuts off refueli

An onboard vapor recovery system for a vehicle fuel system having a fuel tank, a filler neck dynamically sealed by high pressure fuel flow from a filler nozzle, and a vapor recovery apparatus such as a carbon canister. The system includes a liquid level operated control valve which shuts off refueling with a two-stage closing operation providing an initial soft shutoff and a final shutoff. The system also preferably includes a valve in the fuel tank to maintain a predetermined pressure head sufficient to hold the system closed against further refueling at least temporarily, and a positive action, one-way check valve in the lower end of the filler pipe to prevent spitback of fuel from the pressurized tank once refueling has ceased.

대표청구항 ▼

In a vehicle fuel system having a fuel tank, a dynamically-sealed filler pipe, and onboard vapor recovery apparatus such as a vapor canister, a fuel vapor venting control system comprising: control valve means in the fuel tank for venting fuel vapor from the tank to the canister at a first higher ra

In a vehicle fuel system having a fuel tank, a dynamically-sealed filler pipe, and onboard vapor recovery apparatus such as a vapor canister, a fuel vapor venting control system comprising: control valve means in the fuel tank for venting fuel vapor from the tank to the canister at a first higher rate when the fuel level is below a first level, at a second lower rate when the fuel level reaches the first level, and for closing when a second higher level is reached; valve means in the fuel tank for maintaining a pressure head in the tank sufficient to induce filler nozzle shutoff when the control valve means is closed and for selectively venting fuel vapor to the canister independent of the control valve means; and check valve means in a lower end of the filler pipe to close the filler pipe with respect to the fuel tank between refueling activity; wherein, the control valve means comprises two stage coaxial valve means responsive to the level of liquid fuel in the tank, the coaxial valve means comprising a liquid level responsive float means, first and second valve means associated with the float means, and vent outlet means, the float means responsive to liquid fuel reaching the first level to force the first valve means to a position partially closing the vent outlet means, the first valve means being yieldably biased from the second valve means, the float means being responsive to liquid fuel level above the first level to force the second valve means against the bias of the first valve means to fully close the vent outlet means.