FUEL TANK DEPRESSURIZATION WITH SHORTENED WAIT TIME
First Claim
1. A method for opening a pressurized fuel system for refilling a fuel tank via a fuel fill pipe, wherein the fuel fill pipe is covered by a remotely-controlled lockable fuel opening, wherein the fuel tank has an air space coupled by a fuel tank isolation valve to an inlet of a carbon canister for treating an air flow to remove fuel vapors, and wherein the carbon canister has an outlet coupled to atmosphere, the method comprising the steps of:
- receiving a request for opening the fuel system when the fuel opening is locked;
opening the fuel tank isolation valve while the fuel opening remains locked;
detecting a high tank pressure condition in which opening the fuel fill pipe is potentially unsafe;
if the high pressure condition is detected, then activating a vacuum assist pump coupled between the carbon canister outlet and atmosphere to increase a flow of treated air through the carbon canister;
measuring fuel tank pressure;
deactivating the vacuum assist pump when the measured tank pressure decreases to a predetermined pressure; and
unlocking the fuel opening.
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Accused Products
Abstract
A method and apparatus for a pressurized fuel system with a fuel tank, a fuel fill pipe, and a remotely-controlled lockable fuel opening which selectably seals the pipe entrance. A carbon canister has an inlet for receiving a flow of air and fuel vapors from the tank and has an outlet providing a treated air flow to atmosphere. A fuel tank isolation valve is connected between the air space and the inlet of the carbon canister for selectively allowing pressurization of the fuel tank, wherein the pressurization must be relieved prior to refilling of fuel to the fuel tank. A vacuum pump is coupled to the outlet of the carbon canister, wherein the vacuum pump is configured to activate to increase air flow through the carbon canister from the fuel tank when the fuel tank isolation valve is opened during refilling.
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Citations
10 Claims
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1. A method for opening a pressurized fuel system for refilling a fuel tank via a fuel fill pipe, wherein the fuel fill pipe is covered by a remotely-controlled lockable fuel opening, wherein the fuel tank has an air space coupled by a fuel tank isolation valve to an inlet of a carbon canister for treating an air flow to remove fuel vapors, and wherein the carbon canister has an outlet coupled to atmosphere, the method comprising the steps of:
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receiving a request for opening the fuel system when the fuel opening is locked; opening the fuel tank isolation valve while the fuel opening remains locked; detecting a high tank pressure condition in which opening the fuel fill pipe is potentially unsafe; if the high pressure condition is detected, then activating a vacuum assist pump coupled between the carbon canister outlet and atmosphere to increase a flow of treated air through the carbon canister; measuring fuel tank pressure; deactivating the vacuum assist pump when the measured tank pressure decreases to a predetermined pressure; and unlocking the fuel opening. - View Dependent Claims (2, 3, 4)
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5. A pressurized fuel system for a vehicle with an internal combustion engine, comprising:
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a fuel tank for holding fuel, the fuel tank providing an air space above the fuel; a fuel fill pipe for conveying fuel from a pipe entrance to the fuel tank during filling; a remotely-controlled lockable fuel opening which selectably seals the pipe entrance; a carbon canister having an inlet for receiving a flow of air and fuel vapors from the air space and having an outlet providing a treated air flow to atmosphere; a fuel tank isolation valve connected between the air space and the inlet of the carbon canister for selectively isolating the fuel tank from the carbon canister to allow pressurization of the fuel tank, wherein the pressurization must be relieved prior to refilling of fuel to the fuel tank; and a vacuum pump coupled to the outlet of the carbon canister, wherein the vacuum pump is configured to activate to increase air flow through the carbon canister from the fuel tank when the fuel tank isolation valve is opened during refilling. - View Dependent Claims (6, 7, 8, 9, 10)
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Specification