Fuel tank pressure sensor rationality for a hybrid vehicle during refueling
First Claim
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1. A method for a fuel emissions system of a hybrid vehicle, comprising:
- during a refueling event when a fuel tank is being refueled and while a fuel tank level is increasing,maintaining a fuel vapor canister vent line restriction; and
indicating degradation of a fuel tank pressure sensor based on a pressure in a canister vent line.
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Abstract
Methods and systems are provided for performing fuel tank pressure sensor rationality for a hybrid electric vehicle during refueling. In one example, a method may include indicating degradation of the fuel tank pressure sensor based on the pressure detected in the canister vent line when the canister vent line is restricted.
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Citations
20 Claims
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1. A method for a fuel emissions system of a hybrid vehicle, comprising:
during a refueling event when a fuel tank is being refueled and while a fuel tank level is increasing, maintaining a fuel vapor canister vent line restriction; and indicating degradation of a fuel tank pressure sensor based on a pressure in a canister vent line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for a hybrid-electric vehicle, comprising:
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a fuel tank isolation valve coupled in a conduit between a fuel tank and a fuel vapor canister; a fuel tank pressure sensor; an evaporative leak check module (ELCM) coupled in a conduit between the fuel vapor canister and atmosphere, the ELCM comprising a vacuum pump, an ELCM pressure sensor, and a change-over valve operable between a first position and a second position; and a controller configured with instructions stored in non-transitory memory that when executed cause the controller to; during refueling of the fuel tank, perform an evaporative leak check routine by; adjusting the change-over valve to the first position; and comparing fuel tank pressure sensor output and ELCM pressure sensor output and indicating degradation of the fuel tank pressure sensor when a rate of change of the fuel tank pressure sensor output is lower than a rate of change of the ELCM pressure sensor output by at least a threshold amount. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method, comprising:
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responsive to a request to perform a fuel tank refuel, comparing fuel tank pressure to atmospheric pressure; when fuel tank pressure is not equal to atmospheric pressure, indicating degradation of a fuel tank pressure sensor based on a correlation between fuel tank pressure sensor output and canister vent line pressure during fuel tank depressurization prior to the fuel tank refuel; and when fuel tank pressure is substantially equal to atmospheric pressure, indicating degradation of the fuel tank pressure sensor based on a correlation between fuel tank pressure sensor output and canister vent line pressure during the fuel tank refuel and while a fuel tank level is increasing. - View Dependent Claims (18, 19, 20)
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Specification