REFUELING DETECTION FOR DIAGNOSTIC MONITOR

• US 20140330482A1
• Filed: 05/01/2013
• Published: 11/06/2014
• Est. Priority Date: 05/01/2013
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Yang, Dennis Seung-Man, Dudar, Aed M., Bunge, Mark Daniel
• Granted Patent: US 8,935,044 B2
• Time in Patent Office: Days
• US Class Current: 701/34.4
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02M 25/08 adding fuel vapours drawn from engine fuel reservoir electrical control of purge system F02D41/003
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system
• CPC Class Codes: G07C 5/00 Registering or indicating the working of vehicles

Abstract

Methods and systems for detecting a refueling event for diagnostics are disclosed. In one example approach a method comprises discontinuing leak diagnostics in response to a temperature change in a fuel vapor canister coupled to a fuel tank in an emission control system while the leak diagnostics are being performed in the emission control system.

Claims

1. A method for a vehicle with an engine comprising:

discontinuing leak diagnostics in response to a temperature change in a fuel vapor canister coupled to a fuel tank in an emission control system while the leak diagnostics are being performed in the emission control system.

2. The method of claim 1, wherein the temperature change comprises a rate of temperature change in the canister greater than a threshold.

3. The method of claim 1, wherein the fuel tank is pressurized and the temperature change comprises a temperature increase in the canister greater than a threshold temperature increase.

4. The method of claim 1, further comprising indicating a refueling event in response to the predetermined temperature change in the fuel vapor canister and venting the fuel tank in response to the indicated refueling event.

5. The method of claim 1, wherein said step of discontinuing the leak diagnostics is further responsive to a temperature sensor coupled to the fuel tank.

6. The method of claim 1, wherein said step of discontinuing the leak diagnostics is further responsive to a pressure sensor coupled to the fuel tank.

7. The method of claim 6, wherein said step of discontinuing the leak diagnostics is responsive to a fault in said pressure sensor.

8. The method of claim 6 wherein said step of discontinuing the leak diagnostics is responsive to both a fuel tank pressure indication from said pressure sensor and said temperature change in the fuel vapor canister.

9. The method of claim 1, wherein the predetermined temperature change is compensated for one or more of an ambient temperature, a fuel type, and an altitude

10. The method of claim 9, further comprising discontinuing venting the fuel tank after a refueling is completed and resuming the leak diagnostics.

11. The method of claim 1, wherein the fuel vapor canister contains activated charcoal.

14. The method of claim 1, wherein the fuel tank is pressurized and the predetermined temperature change comprises a temperature increase in the canister greater than a threshold temperature increase.

15. The method of claim 1, further comprising indicating a refueling event in response to the predetermined temperature change in the fuel vapor canister and venting the fuel tank in response to the indicated refueling event.

16. The method of claim 1, wherein said step of discontinuing the leak diagnostics is further responsive to a temperature sensor coupled to the fuel tank and an ambient temperature.

17. The method of claim 1, wherein said step of discontinuing the leak diagnostics is further responsive to a pressure sensor coupled to the fuel tank.

12. A method for a vehicle with an engine comprising:

during engine off conditions;

performing leak diagnostics in a fuel emission control system of the engine; and

in response to a predetermined temperature change in a fuel vapor canister in a vent path of a fuel tank, ceasing the leak diagnostics.

13. The method of claim 12, wherein the predetermined temperature change comprises a rate of temperature increase in the canister greater than a threshold and wherein ceasing further comprises powering down a control module carrying out the leak diagnostics.

18. A method for a vehicle with an engine comprising:

during engine off conditions;

performing leak diagnostics in a fuel emission control system of the engine;

detecting a refueling event based on a predetermined temperature change in a fuel vapor canister in a vent path of a fuel tank; and

ceasing the leak diagnostics in response to detecting the refueling event.

19. The method of claim 18, wherein the predetermined temperature change comprises a rate of temperature increase in the canister greater than a threshold.

20. The method of claim 18, wherein the step of detecting a refueling event is further responsive to a temperature sensor coupled to the fuel tank.