Method and system for detecting a fault during catalyst light-off

• US 8,504,278 B2
• Filed: 10/29/2009
• Issued: 08/06/2013
• Est. Priority Date: 10/29/2009
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Verner, Douglas R., Shibata, Jonathan T., Rayl, Allen B., Santoso, Halim G, Buslepp, Kenneth J.
• Primary Examiner(s): Cronin, Stephen K
• Assistant Examiner(s): NAJMUDDIN, RAZA NEHAL
• Application Number:
  US12/608,254
• Publication Number:
  US 20110106392A1
• Time in Patent Office: 1,377 Days
• Field of Search: 123/295, 123/296, 123/297, 123/299, 123/300, 123/688, 123/676, 123/697, 123/703, 701/101, 701/102, 701/103, 701/104, 701/105, 701/109, 701/113, 602/99, 603/00, 603/03
• US Class Current: 701/109
• CPC Class Codes: F01N 3/101 Three-way catalysts
• CPC Class Codes: F02D 41/0255 to accelerate the warming-up of the exhaust gas treating apparatus at engine start
• CPC Class Codes: F02D 41/1494 Control of sensor heater
• CPC Class Codes: F02D 41/1495 Detection of abnormalities in the air/fuel ratio feedback system
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/405 with post injections
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A system and method for controlling engine operation includes a timer module that determines a time period from when a catalyst light-off mode is entered to when an oxygen sensor signal reaches an oxygen sensor threshold and a comparison module that generates an error signal and determines when the time period is above a time threshold.

Claims

1. A method of controlling engine operation, the method comprising:

entering a catalyst light-off mode;

initiating a timer in response to entering the catalyst light-off mode;

generating an oxygen sensor signal;

when the oxygen sensor signal reaches an oxygen sensor threshold, determining a time period from the timer; and

when the time period is greater than a first time threshold, generating a first error signal corresponding to an oxygen sensor heater error.

2. A method as recited in claim 1 further comprising generating a no-fault signal when the time period is less than the first time threshold.

3. A method as recited in claim 1 further comprising generating a second error signal corresponding to a catalyst light-off mode error when the time period is less than the first time threshold and greater than a second time threshold.

4. A method as recited in claim 1 wherein after entering the catalyst light-off mode, providing split-pulse fuel injection into cylinders of the engine that comprise a first pulse and a second pulse.

5. A method as recited in claim 4 further comprising generating a second error signal corresponding to a split-pulse error when the time period is less than the first time threshold and greater than a second time threshold.

6. A method as recited in claim 4 further comprising generating a second error signal corresponding to a missed second pulse when the time period is less than the first time threshold and greater than a second time threshold.

7. A method as recited in claim 1 wherein generating an oxygen sensor signal comprises generating an oxygen sensor signal corresponding to a catalyst temperature.

8. A method as recited in claim 1 wherein generating an oxygen sensor signal comprises an oxygen sensor voltage signal.

9. A method as recited in claim 8 wherein the oxygen sensor voltage signal corresponds to an oxygen sensor impedance.

19. A method as recited in claim 1 further comprising generating a second sensor error signal corresponding to both the oxygen sensor heater error and a catalyst light-off mode error when the time period is greater than a second time threshold, wherein the second time threshold is greater than the first time threshold.

10. A system for controlling engine operation, comprising:

a timer module that determines a time period from when a catalyst light-off mode is entered to when an oxygen sensor signal reaches an oxygen sensor threshold; and

a comparison module that generates a first error signal corresponding to an oxygen sensor heater error when the time period is greater than a first time threshold.

11. A system as recited in claim 10 wherein the comparison module generates a no-fault signal when the time period is less than the time threshold.

12. A system as recited in claim 10 wherein the comparison module generates a second error signal corresponding to a catalyst light-off mode error when the time period is less than the first time threshold and greater than a second time threshold.

13. A system as recited in claim 10 further comprising a catalyst light-off mode module that generates a split-pulse fuel injection into cylinders of the engine comprising a first pulse and a second pulse.

14. A system as recited in claim 13 wherein the comparison module generates a second error signal corresponding to a split-pulse error when the time period is less than the first time threshold and greater than a second time threshold.

15. A system as recited in claim 13 wherein the comparison module generates a second error signal corresponding to a missed second pulse when the time period is less than the first time threshold and greater than a second time threshold.

16. A system as recited in claim 10 wherein generating an oxygen sensor signal comprises generating an oxygen sensor signal corresponding to a catalyst temperature.

17. A system as recited in claim 10 wherein the oxygen sensor signal comprises an oxygen sensor voltage signal.

18. A system as recited in claim 17 wherein the oxygen sensor voltage signal corresponds to an oxygen sensor impedance.

20. A system as recited in claim 10 wherein the comparison module generates a second sensor error signal corresponding to both the oxygen sensor heater error and a catalyst light-off mode error when the time period is greater than a second time threshold, wherein the second time threshold is greater than the first time threshold.