초록 ▼

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 pur

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.

대표청구항 ▼

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 va

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; andindicating 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; andwherein 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.