Canister purge valve self-cleaning cycle
First Claim
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1. A method for a fuel system coupled to an engine, comprising:
- under predetermined engine operating conditions, closing a fuel tank isolation valve, then opening a canister purge valve; and
maintaining the fuel tank isolation valve closed and maintaining the canister purge valve open until after a canister vent solenoid valve has been pulsed open and closed one or more times to generate pressure pulsations in a conduit coupled to the canister purge valve.
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Abstract
A method for a fuel system coupled to an engine comprising: under vacuum conditions, opening the fuel vapor canister purge valve, and generating pressure pulsations in a conduit coupled to the fuel vapor canister purge valve by opening and closing a fuel vapor canister vent valve one or more times while maintaining the fuel vapor canister purge valve open. In this way, contaminants and/or debris that may prevent the canister purge valve from closing completely may be dislodged and evacuated to the intake manifold.
20 Citations
16 Claims
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1. A method for a fuel system coupled to an engine, comprising:
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under predetermined engine operating conditions, closing a fuel tank isolation valve, then opening a canister purge valve; and maintaining the fuel tank isolation valve closed and maintaining the canister purge valve open until after a canister vent solenoid valve has been pulsed open and closed one or more times to generate pressure pulsations in a conduit coupled to the canister purge valve. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for cleaning a fuel vapor canister purge valve, comprising:
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under vacuum conditions, where vacuum conditions include a manifold absolute pressure that is greater than a predetermined threshold, closing a fuel tank isolation valve, then opening the fuel vapor canister purge valve; and generating pressure pulsations in a conduit coupled to the fuel vapor canister purge valve by opening and closing a fuel vapor canister vent valve one or more times while maintaining the fuel tank isolation valve closed and maintaining the fuel vapor canister purge valve open until after one or more pulsations. - View Dependent Claims (11, 12)
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13. A fuel system for a vehicle, comprising:
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a fuel tank for storing fuel used by a vehicle engine; a fuel vapor canister coupled to the fuel tank for receiving and storing fuel tank vapors; a fuel tank isolation valve coupled between the fuel tank and the fuel vapor canister; a fuel vapor canister purge valve coupled between the fuel vapor canister and an engine intake manifold for delivering stored fuel tank vapors from the fuel vapor canister to the engine; a fuel vapor canister vent solenoid valve coupled between the fuel vapor canister and atmosphere; and a controller including computer readable instructions for, in response to a manifold absolute pressure being higher than a threshold during engine-on conditions, closing the fuel tank isolation valve, then opening the fuel vapor canister purge valve for a predetermined duration, and maintaining the fuel tank isolation valve closed and maintaining the fuel vapor canister purge valve open, until after the fuel vapor canister vent solenoid valve has been pulsed open and closed one or more times to generate pressure pulsations in a conduit coupled to the canister purge valve. - View Dependent Claims (14, 15, 16)
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Specification