METHODS AND SYSTEMS FOR FUEL LEVEL INDICATORS IN A SADDLE FUEL TANK

• US 20160313171A1
• Filed: 04/27/2015
• Published: 10/27/2016
• Est. Priority Date: 04/27/2015
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Dudar, Aed M., Mullins, John
• Granted Patent: US 9,829,370 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F02M 37/0094 Saddle tanks; Tanks having partition walls
• CPC Class Codes: G01F 23/32 using rotatable arms or other pivotable transmission elements

Abstract

Methods and systems are provided for diagnosing fuel level indicators in a saddle fuel tank. In one example, a method may include determining degradation of each of the first and the second fuel level indicators included in a first compartment and a second compartment of a saddle tank based on a correlation between changes in fuel tank pressure during the refueling event and an indication by the fuel level indicators of the first and the second compartment reaching full capacity.

Claims

1. A method for an engine, comprising:

indicating degradation of one or more of a first fuel level indicator coupled to a first compartment of a fuel tank and a second fuel level indicator coupled to a second compartment of the fuel tank based on a deviation of a fuel tank pressure from a steady state pressure during a refueling event; and

indicating a fuel tank level based on the fuel tank pressure responsive to the degradation.

2. The method of claim 1, further comprising:

indicating degradation of the first fuel level indicator responsive to the fuel tank pressure sensor indicating a start of fuel transfer from the first compartment to the second compartment asynchronously from the first fuel level indicator indicating that the first compartment has reached a full capacity, wherein the fuel tank level is indicated to an operator of a vehicle in which the engine is positioned via a display.

3. The method of claim 2, further comprising:

indicating that the first fuel level indicator has a bent float arm responsive to the first fuel level indicator indicating that the first compartment has reached a full capacity prior to the fuel tank pressure sensor indicating the start of fuel transfer from the first compartment to the second compartment.

4. The method of claim 2, further comprising:

indicating that the first fuel level indicator has a stuck float arm responsive to the first fuel level indicator reaching a maximum level less than a full fuel tank when the fuel tank pressure sensor indicates the start of fuel transfer from the first compartment to the second compartment.

5. The method of claim 2, further comprising:

indicating degradation of the second fuel level indicator responsive to the fuel tank pressure sensor indicating that the second compartment has reached a full capacity asynchronously from the second fuel level indicator indicating that the second compartment has reached a full capacity.

6. The method of claim 5, further comprising:

indicating that the second fuel level indicator has a bent float arm responsive to the second fuel level indicator indicating that the second compartment has reached a full capacity prior to the fuel tank pressure sensor indicating that the second compartment has reached a full capacity.

7. The method of claim 5, further comprising:

indicating that the second fuel level indicator has a stuck float arm responsive to the second fuel level indicator reaching a maximum level less than a full fuel tank when the fuel tank pressure sensor indicates that the second compartment has reached a full capacity.

8. The method of claim 5, wherein the indication of start of fuel transfer by the pressure sensor is based on a first deviation of the fuel tank pressure from a first steady state pressure.

9. The method of claim 8, wherein the indication that the second compartment has reached a full capacity by the pressure sensor is based on a second deviation of the fuel tank pressure from a second steady state pressure.

10. The method of claim 1, further comprising:

indicating a restriction between the first compartment and the second compartment responsive to the fuel tank pressure sensor indicating a premature end of refueling while the second fuel level indicator indicates a fuel level in the second compartment below a threshold level.

11. The method of claim 1, further comprising:

in response to the indication of degradation of one or more of the first fuel level indicator and the second fuel level indicator, adjusting a parameter for an evaporative emissions leak test performed during an engine-on condition, wherein the leak test includes monitoring a fuel transfer between the first compartment and the second compartment based on the first fuel level indicator and the second fuel level indicator.

12. A method for a vehicle fuel system, comprising:

during an engine on condition, adjusting a parameter of an evaporative emissions leak test responsive to a fuel transfer between a first compartment and a second compartment of a saddle fuel tank via a conduit fluidly coupling the first and the second compartments.

13. The method of claim 12, wherein the fuel transfer is determined based on an output of a first fuel level indicator coupled within the first compartment and an output of a second fuel level indicator coupled within the second compartment.

14. The method of claim 12, wherein adjusting a parameter of the evaporative emissions leak test includes adjusting a leak test threshold responsive to a fuel transfer amount less than a threshold.

15. The method of claim 14, further comprising:

aborting the evaporative emissions leak test responsive to a fuel transfer amount greater than the threshold.

16. The method of claim 12, further comprising:

adjusting a parameter of the evaporative emissions leak test responsive to an indication of degradation of one or more of the first fuel level indicator and the second fuel level indicator.

17. The method of claim 16, wherein degradation of one or more of the first fuel level indicator and the second fuel level indicator is determined during a refueling event based on a correlation between a deviation of a fuel tank pressure from a steady state pressure, a first fuel level indicator output, and a second fuel level indicator output.

18. A vehicle fuel system, comprising:

a first fuel compartment including a fuel pump and a jet pump, the jet pump configured to pump liquid fuel from a second compartment to the first compartment during engine operation;

a fuel tank pressure transducer coupled to the first fuel compartment;

a first fuel level indicator coupled within the first fuel compartment;

a second fuel level indicator coupled within the second fuel compartment; and

a controller configured with instructions stored in non-transitory memory, that when executed, cause the controller to;

during a first condition, indicate degradation of the first fuel level indicator responsive to an indication of fuel transfer from the first compartment to the second compartment occurring asynchronously from the first fuel level indicator indicating that the first compartment has reached full capacity; and

during a second condition, adjust an evaporative emissions leak test threshold responsive to an indication of fuel transfer from the first compartment to the second compartment.

19. The system of claim 18, wherein the first condition includes a refueling event, and wherein the indication of fuel transfer from the first compartment to the second compartment is based on a deviation of a fuel tank pressure from a steady state pressure, the deviation including a pressure spike.

20. The system of claim 18, wherein the second condition includes an ongoing or imminent engine-on evaporative emissions leak test, and wherein the indication of fuel transfer is determined based on a decrease in a first fuel level indicator output and a corresponding increase in a second fuel level indicator output.