FILTERING FOR ROUGH ROAD DETECTION

• US 20090120175A1
• Filed: 05/09/2008
• Published: 05/14/2009
• Est. Priority Date: 11/09/2007
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Mathews, David S., Assaf, Tameem K., Naik, Sanjeev M.
• Granted Patent: US 7,950,273 B2
• Time in Patent Office: Days
• US Class Current: 73/114.120
• CPC Class Codes: B60W 2510/1045 Output speed change rate
• CPC Class Codes: B60W 2552/35 Road bumpiness, e.g. potholes
• CPC Class Codes: B60W 40/072 Curvature of the road
• CPC Class Codes: B60W 40/076 Slope angle of the road
• CPC Class Codes: F02D 2200/0404 Throttle position
• CPC Class Codes: F02D 2200/1015 Engines misfires
• CPC Class Codes: F02D 2200/702 Road conditions
• CPC Class Codes: F02D 41/0225 in relation with the gear ratio or shift lever position
• CPC Class Codes: F02D 41/023 in relation with the gear ratio shifting conjoint control for improving gear change B60W30/19
• CPC Class Codes: G01M 15/11 by detecting misfire

Abstract

An engine misfire system comprises a rough road detection module and a misfire detection module. The rough road detection module selectively generates a rough road indicator based upon a transmission output speed of a vehicle. The misfire detection module selectively diagnoses engine misfire and selectively generates a misfire indicator based on diagnosed engine misfire and the rough road indicator.

Claims

1. An engine misfire system comprising:

a rough road detection module that selectively generates a rough road indicator based upon a transmission output speed of a vehicle; and

a misfire detection module that selectively diagnoses engine misfire and that selectively generates a misfire indicator based on diagnosed engine misfire and said rough road indicator.

2. The engine misfire system of claim 1 wherein said rough road detection module disables generation of said rough road indicator when at least one of a gear shift is occurring and said transmission output speed is less than a predetermined speed.

3. The engine misfire system of claim 2 wherein said rough road detection module disables generation of said rough road indicator when a transmission of said vehicle is in one of park and neutral.

4. The engine misfire system of claim 2 wherein said rough road detection module disables generation of said rough road indicator while a torque converter clutch transitions between a first state and a second state.

5. The engine misfire system of claim 2 wherein said rough road detection module disables generation of said rough road indicator when an engine load transitions across a load threshold.

6. The engine misfire system of claim 2 wherein said rough road detection module selectively performs a statistical analysis of derivatives of said transmission output speed and disables performance of said statistical analysis when generation of said rough road indicator is disabled.

7. The engine misfire system of claim 6 wherein performance of said statistical analysis remains disabled for a period of time after generation of said rough road indicator is reenabled.

8. The engine misfire system of claim 6 wherein said rough road detection module generates a statistical value for one of said derivative values based upon said one of said derivative values and a result of said statistical analysis, and

wherein said rough road detection module generates said rough road indicator based upon a comparison of said statistical value with a predetermined rough road value.

9. The engine misfire system of claim 8 wherein said result of said statistical analysis is an average of said derivative values, and

wherein said statistical value is generated based on a magnitude of a difference of said one of said derivative values and said result of said statistical analysis.

10. The engine misfire system of claim 1 wherein said misfire detection module selectively disables generation of said misfire indicator when said rough road indicator is generated during a period of time.

11. The engine misfire system of claim 10 wherein said misfire detection module enables generation of said misfire indicator when said rough road indicator is generated during said period and at least one of an abusive misfire and a periodic misfire is detected during said period.

12. The engine misfire system of claim 11 wherein said misfire detection module detects said periodic misfire when more than a first predetermined number of engine misfires are diagnosed within a cylinder during said period.

13. The engine misfire system of claim 11 wherein said misfire detection module detects said abusive misfire when more than a second predetermined number of engine misfires are diagnosed during said period.

14. An engine misfire system comprising:

a rough road detection module in a vehicle that selectively generates a rough road indicator and that disables generation of said rough road indicator when at least one of a gear shift is occurring and a speed of said vehicle is less than a predetermined speed; and

a misfire detection module that selectively diagnoses engine misfire and that selectively generates a misfire indicator based on diagnosed engine misfire and said rough road indicator.

15. The engine misfire system of claim 14 wherein said speed is a transmission output speed of said vehicle.

16. The engine misfire system of claim 14 wherein said rough road detection module disables generation of said rough road indicator when a transmission of said vehicle is in one of park and neutral.

17. The engine misfire system of claim 14 wherein said rough road detection module disables generation of said rough road indicator while a torque converter clutch transitions between a first state and a second state.

18. The engine misfire system of claim 14 wherein said rough road detection module disables generation of said rough road indicator when an engine load transitions across a load threshold.

19. The engine misfire system of claim 14 wherein said rough road detection module selectively performs a statistical analysis of derivative values of said speed and disables performance of said statistical analysis when generation of said rough road indicator is disabled.

20. The engine misfire system of claim 19 wherein performance of said statistical analysis remains disabled for a period of time after generation of said rough road indicator is reenabled.

21. The engine misfire system of claim 19 wherein said rough road detection module generates a statistical value for one of said derivative values based upon said one of said derivative values and a result of said statistical analysis, and

wherein said rough road detection module generates said rough road indicator based upon a comparison of said statistical value with a predetermined rough road value.

22. The engine misfire system of claim 21 wherein said result of said statistical analysis is an average of said derivative values, and

wherein said statistical value is generated based on a magnitude of a difference of said one of said derivative values and said result of said statistical analysis.

23. The engine misfire system of claim 14 wherein said misfire detection module selectively disables generation of said misfire indicator when said rough road indicator is generated during a period of time.

24. The engine misfire system of claim 23 wherein said misfire detection module enables generation of said misfire indicator when said rough road indicator is generated during said period and at least one of an abusive misfire and a periodic misfire is detected during said period.

25. The engine misfire system of claim 24 wherein said misfire detection module detects said periodic misfire when more than a first predetermined number of engine misfires are diagnosed within a cylinder during said period.

26. The engine misfire system of claim 24 wherein said misfire detection module detects said abusive misfire when more than a second predetermined number of engine misfires are diagnosed during said period.

27. A method comprising:

selectively generating a rough road indicator based upon a transmission output speed of a vehicle;

selectively diagnosing engine misfire; and

selectively generating a misfire indicator based on diagnosed engine misfire and said rough road indicator.

28. The method of claim 27 further comprising disabling generation of said rough road indicator when at least one of a gear shift is occurring and said transmission output speed is less than a predetermined speed.

29. The method of claim 28 further comprising disabling generation of said rough road indicator when a transmission of said vehicle is in one of park and neutral.

30. The method of claim 28 further comprising disabling generation of said rough road indicator while a torque converter clutch transitions between a first state and a second state.

31. The method of claim 28 further comprising disabling generation of said rough road indicator when an engine load transitions across a load threshold.

32. The method of claim 28 further comprising:

selectively performing a statistical analysis of derivatives of said transmission output speed; and

disabling performance of said statistical analysis when generation of said rough road indicator is disabled.

33. The method of claim 32 wherein performance of said statistical analysis remains disabled for a period of time after generation of said rough road indicator is reenabled.

34. The method of claim 32 further comprising:

generating a statistical value for one of said derivative values based upon said one of said derivative values and a result of said statistical analysis; and

generating said rough road indicator based upon a comparison of said statistical value with a predetermined rough road value.

35. The method of claim 34 wherein said result of said statistical analysis is an average of said derivative values, and

wherein said statistical value is generated based on a magnitude of a difference of said one of said derivative values and said result of said statistical analysis.

36. The method of claim 27 further comprising selectively disabling generation of said misfire indicator when said rough road indicator is generated during a period of time.

37. The method of claim 36 further comprising enabling generation of said misfire indicator when said rough road indicator is generated during said period and at least one of an abusive misfire and a periodic misfire is detected during said period.

38. The method of claim 37 further comprising detecting said periodic misfire when more than a first predetermined number of engine misfires are diagnosed within a cylinder during said period.

39. The method of claim 37 further comprising detecting said abusive misfire when more than a second predetermined number of engine misfires are diagnosed during said period.

40. A method comprising:

selectively generating a rough road indicator;

disabling generation of said rough road indicator when at least one of a gear shift is occurring and a speed of said vehicle is less than a predetermined speed;

selectively diagnosing engine misfire; and

selectively generating a misfire indicator based on diagnosed engine misfire and said rough road indicator.

41. The method of claim 40 wherein said speed is a transmission output speed of said vehicle.

42. The method of claim 40 further comprising disabling generation of said rough road indicator when a transmission of said vehicle is in one of park and neutral.

43. The method of claim 40 further comprising disabling generation of said rough road indicator while a torque converter clutch transitions between a first state and a second state.

44. The method of claim 40 further comprising disabling generation of said rough road indicator when an engine load transitions across a load threshold.

45. The method of claim 40 further comprising:

selectively performing a statistical analysis of derivative values of said speed; and

disabling performance of said statistical analysis when generation of said rough road indicator is disabled.

46. The method of claim 45 wherein performance of said statistical analysis remains disabled for a period of time after generation of said rough road indicator is reenabled.

47. The method of claim 45 further comprising:

generating a statistical value for one of said derivative values based upon said one of said derivative values and a result of said statistical analysis; and

generating said rough road indicator based upon a comparison of said statistical value with a predetermined rough road value.

48. The method of claim 47 wherein said result of said statistical analysis is an average of said derivative values, and

wherein said statistical value is generated based on a magnitude of a difference of said one of said derivative values and said result of said statistical analysis.

49. The method of claim 40 further comprising selectively disabling generation of said misfire indicator when said rough road indicator is generated during a period of time.

50. The method of claim 49 further comprising enabling generation of said misfire indicator when said rough road indicator is generated during said period and at least one of an abusive misfire and a periodic misfire is detected during said period.

51. The method of claim 50 further comprising detecting said periodic misfire when more than a first predetermined number of engine misfires are diagnosed within a cylinder during said period.

52. The method of claim 50 further comprising detecting said abusive misfire when more than a second predetermined number of engine misfires are diagnosed during said period.