Fuel level indication noise monitor

Patent metadata

Field	Value
Publication number	US-9541024-B2
Application number	US-201514661609-A
Country	US
Kind code	B2
Filing date	Mar 18, 2015
Priority date	Mar 18, 2015
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

Methods and systems are provided for monitoring fuel level indicator noise in a sealed fuel tank system. In one example, the method includes comparing the outputs of a fuel level indicator and fuel tank pressure sensor in a sealed tank. If the outputs of both the fuel level indicator and the fuel tank pressure sensor outputs are noisy, then it may be determined that the fuel level indicator noise is mechanical in nature. However, if the fuel level indicator output is noisy while the fuel tank pressure sensor output is not noisy in the sealed tank, then it may be determined that the fuel tank pressure sensor noise is electrical in nature.

First claim

The invention claimed is:

1. A method for an engine fuel system, comprising:
indicating degradation of a fuel tank fuel level indicator based on each of a fuel level indicator output and a fuel tank pressure sensed in a sealed fuel tank system.

2. The method of claim 1 , wherein the fuel system includes a canister coupled to the fuel tank, the method further comprising, sealing the fuel tank system by closing a canister vent valve coupling the canister to atmosphere.

3. The method of claim 1 , further comprising, in response to the indication of degradation, reducing a maximum torque output of the engine.

4. The method of claim 1 , wherein the indicating includes indicating degradation of the fuel level indicator responsive to fluctuations in the fuel level indicator output not correlating with fluctuations in fuel tank pressure in the sealed fuel system.

5. The method of claim 1 , wherein indicating degradation of the fuel tank level indicator includes setting a diagnostic code indicating electrical noise at the fuel tank level indicator.

6. The method of claim 1 , further comprising indicating mechanical noise at the fuel level indicator responsive to fluctuations in the fuel level indicator output correlating with fluctuations in fuel tank pressure in the sealed fuel system.

7. The method of claim 6 , wherein indicating mechanical noise includes indicating mechanical noise at the fuel level indicator due to fuel slosh in the fuel tank.

8. The method of claim 2 , wherein the closing of the canister vent valve is in response to fuel level indicator noise.

9. A method for an engine fuel system, comprising:
in response to fuel level indicator noise,
sealing the fuel system; and
differentiating between electrical noise and mechanical noise of a fuel level indicator based on fuel level indicator noise relative to fuel tank pressure noise in the sealed fuel system.

10. The method of claim 9 , wherein the fuel level indicator is coupled to a fuel tank, wherein the fuel system further includes a fuel vapor canister coupled to the fuel tank, and wherein sealing the fuel system includes actuating a solenoid to close a canister vent valve coupled between the canister and atmosphere.

11. The method of claim 9 , wherein the differentiating includes,
indicating electrical noise when fuel level indicator noise is higher than a threshold and fuel tank pressure noise is lower than the threshold; and
indicating mechanical noise when each of fuel level indicator noise and fuel tank pressure noise is higher than the threshold.

12. The method of claim 9 , wherein the differentiating includes,
indicating electrical noise when fuel level indicator noise and fuel tank pressure noise in the sealed fuel system are not correlated; and
indicating mechanical noise when fuel level indicator noise and fuel tank pressure noise in the sealed fuel system are correlated.

13. The method of claim 12 , wherein indicating electrical noise includes indicating a degraded sensor of the fuel level indicator, and wherein indicating mechanical noise includes indicating fuel slosh in the fuel tank.

14. The method of claim 12 , further comprising, in response to an indication of electrical noise, setting a diagnostic code, and in response to an indication of mechanical noise, not setting a diagnostic code.

15. A system for an engine fuel system of a vehicle, comprising:
a fuel tank including a fuel level indicator for estimating a level of fuel in the fuel tank and a pressure sensor for estimating a fuel tank pressure;
a canister for receiving fuel vapors from the fuel tank;
a canister vent valve coupling the canister to atmospheric air; and
a controller configured with instructions stored in non-transitory memory that when executed cause the controller to:
indicate fuel level indicator noise based on an output of the fuel level indicator; and
in response to the fuel level indicator noise,
seal the fuel tank;
compare fuel level indicator noise to fuel tank pressure sensor output in the sealed fuel tank; and
identify one of mechanical noise and electrical noise of the fuel level indicator based on the comparison.

16. The system of claim 15 , wherein the canister vent valve includes a solenoid, and wherein sealing the fuel tank includes energizing the solenoid to close the canister vent valve.

17. The system of claim 15 , wherein the identifying includes:
identifying the fuel level indicator noise as mechanical noise when each of the fuel level indicator and the fuel tank pressure sensor output are noisy; and
identifying the fuel level indicator noise as electrical noise when the fuel level indicator output is noisy and the fuel tank pressure sensor output is not noisy.

18. The system of claim 15 wherein comparing fuel level indicator noise to fuel tank pressure sensor output comprises comparing fuel level indicator output fluctuations to fuel tank pressure sensor output fluctuations in the sealed fuel tank.

19. The system of claim 17 , wherein the controller includes further instructions for:
setting a diagnostic code upon identifying the noise as electrical noise; and
not setting a diagnostic code upon identifying the noise as mechanical noise.

20. The system of claim 19 , wherein the controller includes further instructions for:
upon identifying the noise as electrical noise, discontinuing estimating the fuel level in the fuel tank based on the fuel level indicator.

Assignees

• Ford Global Tech Llc

Inventors

• Dudar Aed M

Classifications

• B60K35/80

  Arrangements for controlling instruments · CPC title

• B60K35/90

  Calibration of instruments, e.g. setting initial or reference parameters; Testing of instruments, e.g. detecting malfunction · CPC title

• B60K35/28

  characterised by the type of the output information, e.g. video entertainment or vehicle dynamics information; characterised by the purpose of the output information, e.g. for attracting the attention of the driver · CPC title

• B60K35/60

  Instruments characterised by their location or relative disposition in or on vehicles (arrangements of lighting devices on dashboards B60Q3/10) · CPC title

• F02D41/222 Primary

  relating to the failure of sensors or parameter detection devices · CPC title