Systems and methods for a fuel vapor canister heating element

• US 10,215,132 B2
• Filed: 10/27/2015
• Issued: 02/26/2019
• Est. Priority Date: 10/27/2015
• 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.
• Primary Examiner(s): Nguyen, Hung Q
• Assistant Examiner(s): Mo, Xiao
• Application Number:
  US14/924,450
• Publication Number:
  US 20170114732A1
• Time in Patent Office: 1,218 Days
• CPC Class Codes: F02D 41/0035 to achieve a special effect, e.g. to warm up the catalyst
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02D 41/221 relating to the failure of actuators or electrically driven elements
• CPC Class Codes: F02M 2025/0881 with means to heat or cool the canister
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system
• CPC Class Codes: F02M 25/0836 Arrangement of valves controlling the admission of fuel vapour to an engine, e.g. valve being disposed between fuel tank or absorption canister and intake manifold
• CPC Class Codes: F02M 25/0854 Details of the absorption canister

Abstract

A method is presented, wherein a fuel vapor canister heating element is activated during a first condition, which includes an engine-off condition, and atmospheric air is directed through the fuel vapor canister and into an engine intake. Degradation of the fuel vapor canister heating element is indicated based on an output of an engine intake air temperature sensor. In this way, the integrity of the fuel vapor canister heating element can be determined without relying on canister temperature sensors, which may be confounded by the cooling of the fuel vapor canister during fuel vapor desorption.

Claims

1. A method, comprising:

during a first condition, including an engine-off condition, activating a fuel vapor canister heating element;

directing atmospheric air through a fuel vapor canister and into an engine intake; and

indicating degradation of the fuel vapor canister heating element based on an output of an engine intake air temperature sensor.

2. The method of claim 1, further comprising:

responsive to an indication of degradation of the fuel vapor canister heating element, adjusting an evaporative emissions system parameter.

3. The method of claim 2, wherein adjusting an evaporative emissions system parameter includes increasing a commanded total airflow through the fuel vapor canister during a subsequent purge event.

4. The method of claim 1, wherein the first condition includes a canister load below a threshold.

5. The method of claim 1, wherein the first condition includes an engine coolant temperature within a threshold of an intake air temperature.

6. The method of claim 1, wherein directing atmospheric air through the fuel vapor canister includes activating a vacuum pump coupled between the fuel vapor canister and atmosphere.

7. The method of claim 6, further comprising:

coupling the fuel vapor canister to atmosphere via the vacuum pump; and

activating the vacuum pump in a conformation to draw atmospheric air into the fuel vapor canister.

8. The method of claim 1, wherein directing atmospheric air through the fuel vapor canister and into an engine intake comprises:

opening a canister purge valve coupled between the fuel vapor canister and the engine intake.

9. The method of claim 8, wherein directing atmospheric air through the fuel vapor canister and into an engine intake further comprises:

closing a fuel tank isolation valve coupled between the fuel vapor canister and a fuel tank.

10. The method of claim 8, wherein directing atmospheric air through the fuel vapor canister and into an engine intake further comprises:

opening a throttle coupled between the engine intake and atmosphere.

11. The method of claim 1, wherein indicating degradation of the fuel vapor canister heating element based on an output of an engine intake air temperature sensor comprises indicating degradation of the fuel vapor canister heating element responsive to an increase in intake air temperature below a threshold.

12. The method of claim 11, further comprising:

indicating functionality of the fuel vapor canister heating element responsive to an increase in intake air temperature greater than the threshold.

13. The method of claim 12, further comprising:

responsive to an indication of functionality of the fuel vapor canister heating element, updating an evaporative emissions system test schedule.

14. A system for an engine, comprising:

a fuel vapor canister;

a fuel vapor canister heating element coupled to the fuel vapor canister;

an intake air temperature sensor coupled within an engine intake;

an engine coolant temperature sensor;

a vacuum pump coupled between the fuel vapor canister and atmosphere; and

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

during a first condition, including a fuel vapor canister load below a threshold and an intake air temperature within a threshold of an engine coolant temperature, activating the fuel vapor canister heating element;

activating the vacuum pump to flow atmospheric air through the fuel vapor canister; and

indicating degradation of the fuel vapor canister heating element responsive to a change in intake air temperature less than a threshold.

15. The system of claim 14, further comprising a canister purge valve coupled between the fuel vapor canister and the engine intake, and wherein the controller is further configured with instructions stored in non-transitory memory, that when executed, cause the controller to:

open the canister purge valve to flow pumped atmospheric air into the engine intake.

16. The system of claim 14, wherein the vacuum pump is operable to flow atmospheric air through the fuel vapor canister in a first conformation, and to draw a vacuum on the fuel vapor canister in a second conformation.

17. The system of claim 14, wherein the first condition includes a vehicle-off condition.

18. The system of claim 14, wherein the controller is further configured with instructions stored in non-transitory memory, that when executed, cause the controller to:

during a second condition, including an engine coolant temperature greater than an intake air temperature by more than a threshold, place the controller in a sleep mode for a duration;

wake the controller; and

activate the fuel vapor canister heating element responsive to an intake air temperature within a threshold of an engine coolant temperature.

19. A method for an evaporative emissions system, comprising:

following a vehicle-off condition, responsive to a fuel vapor canister load less than a threshold and an engine coolant temperature within a threshold of an engine intake air temperature, activating a fuel vapor canister heating element;

isolating a fuel vapor canister from a fuel tank;

coupling the fuel vapor canister to atmosphere via an evaporative leak check module vacuum pump;

activating the evaporative leak check module vacuum pump in a conformation to pump atmospheric air into the fuel vapor canister;

opening a canister purge valve;

opening an air intake throttle;

indicating degradation of the fuel vapor canister heating element responsive to a change in intake air temperature less than a threshold; and

adjusting one or more evaporative emissions system parameters responsive to an indication of degradation of the fuel vapor canister heating element.

20. The method of claim 19, further comprising:

indicating functionality of the fuel vapor canister heating element responsive to a change in intake air temperature greater than a threshold; and

updating one or more evaporative emissions system testing schedules.