Leak detection for canister purge valve

Patent metadata

Field	Value
Publication number	US-9255553-B2
Application number	US-201313939096-A
Country	US
Kind code	B2
Filing date	Jul 10, 2013
Priority date	Jul 10, 2013
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

Methods and systems for detecting a leak in a canister purge valve are disclosed. In one example approach, a method comprises indicating a leak in response to a temperature change in a fuel vapor canister coupled to a fuel tank in an emission control system while the engine is in operation and a purge valve is closed.

First claim

The invention claimed is:

1. A method for a vehicle with an engine comprising:
indicating a leak in response to a temperature change in a fuel vapor canister coupled to a fuel tank in an emission control system while the engine is in operation and a purge valve is closed;
wherein indicating the leak in response to the fuel vapor canister temperature change is performed in response to a fault in a pressure sensor coupled to the fuel tank.

2. The method of claim 1 , wherein the temperature change comprises a temperature decrease in the canister.

3. The method of claim 1 , wherein the temperature change comprises a temperature decreasing below a threshold temperature.

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

5. The method of claim 1 , wherein indicating the leak is further responsive to a pressure sensor coupled to the fuel tank.

6. The method of claim 5 , wherein indicating the leak responsive to the pressure sensor coupled to the fuel tank comprises indicating a leak in response to a pressure decrease in the fuel tank while the engine is in operation and a purge valve is closed.

7. The method of claim 1 , wherein the purge valve is disposed in a conduit coupling the canister to an intake of the engine.

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

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

10. A method for a vehicle with an engine comprising:
during engine-on conditions:
closing or maintaining a purge valve closed; and
indicating a leak in response to a temperature change in a fuel vapor canister coupled to a fuel tank in an emission control system;

wherein indicating the leak in response to the temperature change in the fuel vapor canister comprises indicating a leak in the purge valve.

11. The method of claim 10 , wherein the temperature change comprises a temperature decreasing below a threshold temperature.

12. The method of claim 10 , wherein the temperature change comprises a rate of temperature decrease in the canister greater than a threshold.

13. The method of claim 10 , wherein indicating the leak in response to the temperature change in the fuel vapor canister is performed in response to a fault in a pressure sensor coupled to the fuel tank.

14. The method of claim 10 , wherein indicating the leak is further responsive to a pressure decrease in the fuel tank while the engine is in operation and the purge valve is closed.

15. The method of claim 10 , wherein during the engine-on conditions, the fuel tank is completely sealed off from atmosphere.

16. A method for a vehicle with an engine comprising:
indicating a leak in response to a temperature decrease in a fuel vapor canister coupled to a fuel tank in an emission control system while the engine is in operation and a purge valve is closed, where the purge valve is disposed in a conduit coupling the canister to an intake of the engine; and
wherein indicating the leak in response to the temperature decrease in the fuel vapor canister is performed in response to a fault in a pressure sensor coupled to the fuel tank.

17. The method of claim 16 , wherein the temperature decrease comprises a temperature decrease below a threshold temperature.

Assignees

• Ford Global Tech Llc

Inventors

• Dudar Aed M
• Yang Dennis Seung-Man

Classifications

• F02D2200/0606

  Fuel temperature · CPC title

• F02D2041/225

  Leakage detection · CPC title

• F02D41/0035

  to achieve a special effect, e.g. to warm up the catalyst · CPC title

• F02D29/02

  peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers · CPC title

• F02M25/0809 Primary

  Judging failure of purge control system · CPC title