Air intake system hydrocarbon trap purging

• US 9,518,540 B2
• Filed: 04/30/2013
• Issued: 12/13/2016
• Est. Priority Date: 04/30/2013
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Pearce, Russell Randall, Dudar, Aed M., Yang, Dennis Seung-Man
• Primary Examiner(s): Cronin, Stephen K
• Assistant Examiner(s): Steckbauer, Kevin R
• Application Number:
  US13/874,225
• Publication Number:
  US 20140318504A1
• Time in Patent Office: 1,323 Days
• Field of Search: 123/516, 123/518, 123/519, 123/520, 123/521, 123/198.D, 123/698, 701/103
• US Class Current: 1/1
• CPC Class Codes: B60K 15/035 characterised by venting means
• CPC Class Codes: B60K 15/03519 Valve arrangements in the vent line
• CPC Class Codes: B60K 2015/03514 with vapor recovery means
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• CPC Class Codes: B60W 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: F02D 19/0621 Purging of the fuel system
• CPC Class Codes: F02D 41/0002 Controlling intake air
• CPC Class Codes: F02D 41/0032 Controlling the purging of the canister as a function of the engine operating conditions
• CPC Class Codes: F02D 41/0045 Estimating, calculating or determining the purging rate, amount, flow or concentration
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02M 25/0818 having means for pressurising the evaporative emission space
• 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 25/089 Layout of the fuel vapour installation
• CPC Class Codes: F02M 33/025 Means not otherwise provided for
• CPC Class Codes: Y10S 903/905 Combustion engine

Abstract

Methods and systems for purging a hydrocarbon trap in an engine intake in a vehicle are disclosed. In one example approach, a method comprises during an engine off condition, operating a pump in a purge line coupled to a fuel vapor canister in an emission control system to deliver fuel stored in a hydrocarbon trap in an intake of the engine to the fuel vapor canister.

Claims

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

during an engine off condition including a sealed fuel tank holding a vacuum below a threshold, operating a pump in a purge line coupled to a fuel vapor canister in an emission control system to deliver fuel stored in an adsorbent in a hydrocarbon trap in an intake of the engine to the fuel vapor canister;

responsive to the engine off condition including a fuel tank vacuum above the threshold, closing a vent valve disposed in a vent path of the fuel vapor canister;

opening an isolation valve coupled between the fuel tank and the fuel vapor canister;

opening a throttle in the intake of the engine;

maintaining the pump in an inactive state;

opening a purge valve in the purge line; and

applying the fuel tank vacuum to the engine intake, thereby purging the fuel stored in the adsorbent in the hydrocarbon trap.

2. The method of claim 1, wherein the engine off condition comprises a vehicle key-off event.

3. The method of claim 1, wherein the pump is disposed in the vent path of the fuel vapor canister.

4. The method of claim 1, further comprising opening the throttle in the intake of the engine and opening the purge valve in the purge line while operating the pump to deliver fuel stored in the adsorbent in the hydrocarbon trap to the fuel vapor canister.

5. The method of claim 4, further comprising closing the purge valve, closing the throttle, and discontinuing operation of the pump in response to an amount of fuel vapor delivered from the hydrocarbon trap to the fuel vapor canister greater than a threshold.

6. The method of claim 1, wherein operating the pump in the purge line coupled to the fuel vapor canister to deliver fuel stored in the adsorbent in the hydrocarbon trap to the fuel vapor canister is performed in response to an amount of fuel vapor stored in the fuel vapor canister less than a threshold.

7. The method of claim 1, wherein intake and exhaust valves in cylinders of the engine are positioned in a closed state while operating the pump in the purge line coupled to the fuel vapor canister to deliver fuel stored in the adsorbent in the hydrocarbon trap to the fuel vapor canister.

8. The method of claim 1, wherein the hydrocarbon trap is coupled in an intake manifold of the engine, wherein the engine off condition includes an amount of fuel stored in adsorbent in a hydrocarbon trap load above a threshold, and wherein the adsorbent is activated carbon.

9. The method of claim 1, further comprising discontinuing operation of the pump following delivery of fuel stored in the adsorbent in the hydrocarbon trap to the fuel vapor canister and, in response to a leak detection event, operating the pump to perform leak diagnostics in the emission control system.

10. The method of claim 1, further comprising discontinuing operation of the pump following delivery of fuel stored in the adsorbent in the hydrocarbon trap to the fuel vapor canister and, in response to a fuel vapor purging event while the engine is in operation, purging fuel vapors stored in the fuel vapor canister to the intake of the engine.

11. A method for a hybrid vehicle with an engine, comprising:

during a first engine off condition when an amount of fuel vapor stored in an activated carbon fuel vapor canister in an emission control system is less than a threshold amount, and an amount of fuel stored in activated carbon within a hydrocarbon trap in an intake of the engine is greater than a threshold amount;

opening a throttle in the intake of the engine;

opening a purge valve in a purge line coupled to the activated carbon fuel vapor canister; and

operating a pump in the purge line to deliver the fuel stored in activated carbon within the hydrocarbon trap in the intake of the engine to the activated carbon fuel vapor canister; and

during a second engine off condition when the amount of fuel vapor stored in the activated carbon fuel vapor canister is less than the threshold amount, and the amount of fuel stored in activated carbon within the hydrocarbon trap is greater than the threshold amount;

opening the throttle;

maintaining the pump off; and

coupling the intake of the engine to a vacuum reservoir, thereby purging the fuel stored in activated carbon within the hydrocarbon trap.

12. The method of claim 11, wherein the first engine off condition comprises a vehicle key-off event.

13. The method of claim 11, wherein the pump is disposed in a vent path of the activated carbon fuel vapor canister;

and wherein the amount of fuel stored in activated carbon within the hydrocarbon trap is based on a cumulative engine-run time.

14. The method of claim 11, further comprising closing the purge valve, closing the throttle, and discontinuing operation of the pump in response to an amount of fuel vapor delivered from the activated carbon within the hydrocarbon trap to the activated carbon fuel vapor canister greater than a threshold.

15. The method of claim 11, wherein the hydrocarbon trap is coupled in an intake manifold of the engine;

and wherein the method further comprises;

responsive to a third engine off condition, wherein the amount of fuel stored in activated carbon within the hydrocarbon trap in the intake of the engine is less than the threshold amount, maintaining the throttle closed;

maintaining the purge valve closed; and

maintaining the pump in an inactive state.

16. The method of claim 11, further comprising closing the purge valve, closing the throttle, and discontinuing operation of the pump following delivery of fuel stored in the activated carbon within the hydrocarbon trap to the activated carbon fuel vapor canister and, in response to the amount of fuel vapor stored in the activated carbon fuel vapor canister greater than the threshold, operating the engine to purge fuel vapors stored in the activated carbon fuel vapor canister to the intake of the engine.

17. The method of claim 11, wherein the first engine off condition includes a vacuum stored within the vacuum reservoir that is below a threshold, and wherein the second engine off condition includes a vacuum stored within the vacuum reservoir that is above a threshold.

18. A hybrid vehicle system, comprising:

a hydrocarbon trap comprising an adsorbent and situated in an intake of an engine;

a fuel vapor canister coupled to the intake of the engine via a purge line, the fuel vapor canister comprising the adsorbent;

a vent valve in a vent path of the fuel vapor canister;

a pump in the vent path of the fuel vapor canister;

a fuel tank coupled to the fuel vapor canister;

an isolation valve coupled between the fuel tank and the fuel vapor canister;

a purge valve in the purge line;

a throttle in the intake of the engine; and

a controller configured to;

during a first engine off condition when an amount of fuel vapor stored in the fuel vapor canister is less than a threshold amount, and an amount of vacuum in the fuel tank is less than a threshold amount;

open the throttle;

open the purge valve;

operate the pump to deliver fuel stored in the hydrocarbon trap to the fuel vapor canister; and

close the purge valve, close the throttle, and discontinue operation of the pump in response to an amount of fuel vapor delivered from the hydrocarbon trap to the fuel vapor canister greater than a threshold; and

during a second engine off condition when the amount of vacuum in the fuel tank is greater than the threshold amount;

close the vent valve;

open the isolation valve;

open the throttle;

maintain the pump in an inactive state;

open the purge valve; and

apply the fuel tank vacuum to the engine intake, thereby purging the fuel stored in the adsorbent in the hydrocarbon trap.

19. The system of claim 18, wherein the controller is further configured to close the purge valve, close the throttle, and discontinue operation of the pump following delivery of fuel stored in the hydrocarbon trap to the fuel vapor canister and, in response to the amount of fuel stored in the fuel vapor canister greater than the threshold, operate the engine to purge fuel vapors stored in the fuel vapor canister to the intake of the engine, and wherein the adsorbent is activated carbon.