Fuel tank pressure sensor rationality testing for plug-in hybrid electric vehicles

Patent metadata

Field	Value
Publication number	US-9945752-B2
Application number	US-201514968461-A
Country	US
Kind code	B2
Filing date	Dec 14, 2015
Priority date	Dec 14, 2015
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

A method for a hybrid-electric vehicle is presented, wherein a fuel tank is sealed closed during a first condition that includes an inductive charging event, and wherein degradation of a fuel tank pressure transducer is indicated responsive to a fuel tank pressure transducer output failing to increase above a threshold following an active testing duration. The outer walls of the fuel tank may include ferrous components which are energized by a magnetic field generated during the inductive charging event, thus heating the fuel tank and the fuel stored within. In this way, the pressure within the sealed fuel tank increases during the inductive charging event, and a determination may be made as to whether the output of the fuel tank pressure transducer is rational.

First claim

The invention claimed is:

1. A method for a hybrid-electric vehicle, comprising:
during a first condition, including an inductive charging event, sealing a fuel tank closed by commanding closure of a fuel tank isolation valve; and
indicating degradation of a fuel tank pressure transducer responsive to a fuel tank pressure transducer output failing to increase above a threshold following an active testing duration implemented during the inductive charging event.

2. The method of claim 1 , further comprising:
updating one or more fuel system parameters responsive to an indication of fuel tank pressure transducer degradation.

3. The method of claim 2 , wherein the one or more fuel system parameters include a fuel system undesired emissions test schedule.

4. The method of claim 1 , wherein the first condition includes a threshold number of previous indeterminate passive fuel tank pressure transducer rationality tests.

5. The method of claim 1 , wherein the first condition includes a previous passive fuel tank pressure transducer rationality test wherein a fuel tank pressure transducer output failed to track with a change in ambient temperature during a vehicle-off soak.

6. The method of claim 5 , wherein the first condition further includes a fuel tank pressure transducer output that is greater than the threshold following the vehicle-off soak of the previous passive fuel tank pressure transducer rationality test.

7. The method of claim 1 , wherein the active testing duration is based on at least a fuel tank fill level.

8. The method of claim 1 , wherein the fuel tank pressure transducer output threshold is based on at least a temperature of fuel stored in the fuel tank.

9. The method of claim 1 , further comprising:
inductively coupling the fuel tank to an inductive charging mat located beneath an underbody of the hybrid-electric vehicle.

10. The method of claim 9 , wherein inductively coupling the fuel tank to the inductive charging mat includes adjusting a position of a magnetic shield coupled to the fuel tank.

11. The method of claim 9 , wherein inductively coupling the fuel tank to the inductive charging mat includes coupling ferrous components of the fuel tank to an energizing circuit that is inductively coupled to the inductive charging mat.

12. The method of claim 9 , further comprising:
decoupling the fuel tank from the inductive charging mat following the active testing duration.

13. A system for a vehicle comprising:
a primary inductive coil external to the vehicle configured to receive electrical power from an external power source for generating a magnetic field;
a secondary inductive coil onboard the vehicle configured such that the magnetic field generated from the primary inductive coil induces a current in the secondary inductive coil in a non-contact manner;
a rechargeable energy storage device configured such that the magnetic field generated from the primary inductive coil inductively charges the rechargeable energy storage device via the induced current in the secondary inductive coil;
a fuel tank including one or more ferrous components at an outer surface of the fuel tank, such that the magnetic field generated from the primary inductive coil energizes the one or more ferrous components;
a fuel tank isolation valve configured to seal the fuel tank from an atmosphere when closed;
a fuel tank pressure transducer positioned between the fuel tank and the fuel tank isolation valve; and
a controller configured with instructions stored in non-transitory memory, that when executed cause the controller to:
close the fuel tank isolation valve during an inductive charging event;
during a first condition, including an indication that the rechargeable energy storage device is being charged via the inductive charging event, monitor an output of the fuel tank pressure transducer; and
indicate degradation of the fuel tank pressure transducer following an active testing duration wherein the output of the fuel tank pressure transducer failed to increase above a threshold during the inductive charging event.

14. The system of claim 13 , wherein the active testing duration is based at least on a level of fuel stored in the fuel tank.

15. The system of claim 13 , wherein the first condition includes an indication of one or more previous indeterminate passive fuel tank rationality tests.

16. The system of claim 13 , further comprising:
a magnetic shield configured to selectively expose the one or more ferrous components at the outer surface of the fuel tank to the magnetic field generated from the primary inductive coil.

17. A method for a hybrid-electric vehicle, comprising:
during a vehicle-off condition and during an inductive charging event, sealing a fuel tank from an atmosphere by closing a fuel tank isolation valve;
indicating an initial fuel tank pressure transducer output and an initial ambient temperature at an initiation of the vehicle-off condition during the inductive charging event;
indicating a final fuel tank pressure transducer output and a final ambient temperature at a termination of the vehicle-off condition;
responsive to the final ambient temperature being that is different from the initial ambient temperature by more than a threshold, indicating whether the final fuel tank pressure transducer output is within a threshold of an expected fuel tank pressure transducer output;
responsive to the final fuel tank pressure transducer output not being within the threshold of the expected fuel tank pressure transducer output, performing an active fuel tank pressure transducer rationality test responsive to the final fuel tank pressure transducer output being more than a threshold from atmospheric pressure; and
responsive to the final fuel tank pressure transducer output not being within the threshold of the expected fuel tank pressure transducer output, performing an undesired evaporative emissions test responsive to the final fuel tank pressure transducer output being less than the threshold from atmospheric pressure.

18. The method of claim 17 , further comprising:
responsive to an indication to perform the active fuel tank pressure transducer rationality test, inductively energizing ferrous components of the fuel tank for an active testing duration while maintaining the fuel tank sealed from an atmosphere; and
indicating degradation of a fuel tank pressure transducer responsive to a fuel tank pressure transducer output failing to increase above a threshold following the active testing duration.

19. The method of claim 18 , wherein inductively energizing ferrous components of the fuel tank comprises positioning the fuel tank above an inductive charging mat configured to generate a magnetic field.

20. The method of claim 19 , wherein inductively energizing ferrous components of the fuel tank comprises actively exposing the ferrous components of the fuel tank to the magnetic field generated by the inductive charging mat.

Assignees

• Ford Global Tech Llc

Inventors

• Dudar Aed M

Classifications

• G01L27/002 Primary

  Calibrating, i.e. establishing true relation between transducer output value and value to be measured, zeroing, linearising or span error determination · CPC title

• G01M17/007

  Wheeled or endless-tracked vehicles (G01M17/08 takes precedence) · CPC title

• G01L27/007

  Malfunction diagnosis, i.e. diagnosing a sensor defect · CPC title