Systems and methods for reducing bleed emissions
First Claim
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1. A method for a fuel system, comprising:
- during a first condition, including an engine-off condition and a sealed fuel tank, directing fresh air into a fuel vapor canister responsive to detecting hydrocarbons in a canister vent line.
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Abstract
A method for a fuel system, comprising: during a first condition, including an engine-off condition and a sealed fuel tank, directing fresh air into a fuel vapor canister responsive to detecting hydrocarbons in a canister vent line. By directing fresh air into the fuel vapor canister, fuel vapor stored within the canister may be redistributed away from the canister vent line. In this way bleed emissions from the fuel system may be reduced without the need for a dedicated bleed canister.
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Citations
19 Claims
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1. A method for a fuel system, comprising:
during a first condition, including an engine-off condition and a sealed fuel tank, directing fresh air into a fuel vapor canister responsive to detecting hydrocarbons in a canister vent line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A fuel system, comprising:
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a fuel vapor canister; an air pump coupled between a vent port of the fuel vapor canister and atmosphere; a controller configured with instructions stored in non-transitory memory, that when executed, cause the controller to; redistribute fuel vapor within the fuel vapor canister away from the vent port by activating the air pump; and a fuel tank isolation valve coupled between the fuel vapor canister and a fuel tank, wherein the controller is further configured with instructions stored in non-transitory memory, that when executed, cause the controller to; maintain the fuel tank isolation valve closed while redistributing fuel vapor within the fuel vapor canister away from the vent port. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method for a vehicle, comprising:
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responsive to a vehicle-off event, setting a hydrocarbon breakthrough detection strategy; responsive to a hydrocarbon sensor output increasing above a threshold, opening a canister purge valve coupled within a canister purge line; coupling a canister vent port to the canister purge line; coupling a canister purge port to a vacuum pump; maintaining a fuel tank isolation valve closed; and activating the vacuum pump. - View Dependent Claims (19)
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Specification