Controlling the closing force of a canister purge valve prior to executing leak diagnostic

Patent metadata

Field	Value
Publication number	US-9284922-B2
Application number	US-201313753393-A
Country	US
Kind code	B2
Filing date	Jan 29, 2013
Priority date	Jan 29, 2013
Publication date	Mar 15, 2016
Grant date	Mar 15, 2016

Abstract

A method for a vehicle having a fuel vapor canister coupled between a fuel tank and an engine intake manifold via an electronically controlled purge valve, comprises initiating a vapor leak test under predetermined conditions and in response to the initiation, fully opening the purge valve from a closed position to a fully open position for a predetermined time, and then fully closing the purge valve after the predetermined time and commencing the leak test.

First claim

The invention claimed is:

1. A method for a vehicle having a fuel vapor canister coupled between a fuel tank and an engine intake manifold via an electronically controlled purge valve, comprising:
initiating a vapor leak test under predetermined conditions; and
in response to said initiation, opening said purge valve from a closed position to an open position for a predetermined time; opening and closing a vent valve coupled to said fuel vapor canister during said predetermined time; closing said purge valve after said predetermined time; fully opening said purge valve for a second predetermined time; and then fully closing said purge valve before commencing said leak test.

2. The method recited in claim 1 further comprising measuring pressure in said fuel vapor canister and wherein said leak test is responsive to a change in said pressure measurement.

3. The method recited in claim 1 further comprising measuring pressure in said fuel tank and wherein said leak test is responsive to a change in said pressure measurement.

4. The method recited in claim 2 further comprising actuating a vacuum pump coupled to said fuel vapor canister during said leak test before commencing said pressure measurement.

5. The method recited in claim 3 further comprising actuating a vacuum pump coupled to said fuel tank during said leak test before commencing said pressure measurement.

6. A method for a vehicle system having a carbon canister coupled between a fuel tank and an engine intake manifold via an electronically controlled purge valve, comprising:
conducting a fuel vapor leak test based on predetermined engine conditions;
before commencing said leak test, opening said purge valve for a preselected time; then closing said purge valve for a first predetermined time; then fully opening said purge valve for a second predetermined time; and then fully closing said purge valve and commencing said leak test.

7. The method recited in claim 6 wherein said second predetermined time is less than said first predetermined time.

8. The method recited in claim 6 further comprising opening and closing a vent valve coupled to said canister during said preselected time.

9. The method recited in claim 6 further comprising measuring pressure in said carbon canister and wherein said leak test is responsive to a change in said pressure measurement.

10. The method recited in claim 6 further comprising measuring pressure in said fuel tank and wherein said leak test is responsive to a change in said pressure measurement.

11. The method recited in claim 10 further comprising actuating a vacuum pump coupled to said canister during said leak test before commencing said pressure measurement.

12. A method for a vehicle system having a carbon canister coupled between a fuel tank and an engine intake manifold via an electronically controlled purge valve, comprising:
initiating a fuel vapor purge based upon preselected engine conditions by opening said purge valve and inducting fuel vapors from said canister into said engine intake manifold;
stopping said fuel vapor purge by closing said purge valve based on a determination that fuel vapors absorbed in said canister are less than a threshold;
initiating a fuel vapor leak test when predetermined conditions are met;
in response to said initiation, fully opening said purge valve from a closed position to a fully open position for a predetermined time; and then fully closing said purge valve; and opening said purge valve for a preselected time before commencing said leak test.

13. The method recited in claim 12 further comprising measuring pressure in said carbon canister or said fuel tank and wherein said leak test is responsive to a change in said pressure measurement.

14. The method recited in claim 13 further comprising actuating a vacuum pump coupled to said canister or said fuel tank during said leak test before commencing said pressure measurement.

15. The method recited in claim 12 wherein said determination that fuel vapors absorbed in said canister are less than said threshold is based upon engine exhaust air/fuel ratio.

16. The method recited in claim 12 wherein fully opening said purge valve from the closed position to the fully open position for said predetermined time is less than said purge valve opening for said preselected time.

Assignees

• Ford Global Tech Llc

Inventors

• Peters Mark W
• Werner Matthew
• Bohr Scott A
• Dudar Aed M

Classifications

• Y02T10/40

  Engine management systems · CPC title

• F02M25/0809 Primary

  Judging failure of purge control system · CPC title