Engine-off refueling detection method
First Claim
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1. A method for an engine fuel system, comprising:
- during an engine-off condition,indicating a refueling event based on a rate of change in fuel tank pressure being greater than a first threshold when a canister vent valve is open, and greater than a second threshold when the canister vent valve is closed, the first threshold being less than the second threshold; and
aborting a diagnostic leak detection test based on the refueling event indication.
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Abstract
A method for an engine fuel system comprises, during an engine-off condition, indicating a refueling event based on a rate of change in fuel tank pressure, and aborting a diagnostic leak detection test based on the refueling event indication. Indicating a refueling event further comprises indicating a refueling event based on the rate of change in fuel tank pressure being greater than a first threshold when the canister vent valve is open, and greater than a second threshold when the canister vent valve is closed, the first threshold being less than the second threshold.
47 Citations
18 Claims
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1. A method for an engine fuel system, comprising:
during an engine-off condition, indicating a refueling event based on a rate of change in fuel tank pressure being greater than a first threshold when a canister vent valve is open, and greater than a second threshold when the canister vent valve is closed, the first threshold being less than the second threshold; and aborting a diagnostic leak detection test based on the refueling event indication. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for a vehicle having a fuel tank pressure sensor, a fuel vapor canister, and a canister vent valve, comprising:
during an engine-off vapor leak test, measuring a fuel tank pressure with the fuel tank pressure sensor; in response to a rate of change in fuel tank pressure being greater than a second threshold when the canister vent valve is closed, aborting the engine-off vapor leak test; determining if the rate of change in fuel tank pressure is greater than a first threshold when the canister vent valve is open, the first threshold being less than the second threshold; and in response to the rate of change in fuel tank pressure being greater than the first threshold, closing the canister vent valve. - View Dependent Claims (16)
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17. A method of providing a refueling indication in a vehicle, comprising:
during a first condition when an engine is off and while a diagnostic leak detection test is being carried out, measuring a fuel tank pressure; in response to a rate of change in fuel tank pressure being greater than a first threshold, closing a canister vent valve; and in response to the rate of change in fuel tank pressure being greater than a second threshold, opening the canister vent valve, setting a refueling event flag on, and aborting the diagnostic leak detection test. - View Dependent Claims (18)
Specification