System and method for monitoring engine valve actuation

• US 7,077,082 B2
• Filed: 12/04/2002
• Issued: 07/18/2006
• Est. Priority Date: 05/14/2002
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Funke, Steven J., Jacobson, Evan E., Bloms, Jason Kenneth, Kagy, Robert A.
• Primary Examiner(s): Denion, Thomas
• Assistant Examiner(s): Riddle, Kyle M.
• Application Number:
  US10/309,317
• Publication Number:
  US 20030213445A1
• Time in Patent Office: 1,322 Days
• Field of Search: 123/90.12, 123/90.15, 123/90.16, 123/90.17, 123/90.18, 123/320, 123/321, 123/322
• US Class Current: 123/90.12
• CPC Class Codes: F01L 1/267 with means for varying the timing or the lift of the valves
• CPC Class Codes: F01L 13/06 for braking
• CPC Class Codes: F01L 2001/34446 Fluid accumulators for the feeding circuit
• CPC Class Codes: F01L 9/11 in which the action of a cam is being transmitted to a valve by a liquid column
• CPC Class Codes: F02B 2275/32 Miller cycle
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An engine valve actuation system is provided. An intake valve is moveable between a first position where the intake valve prevents a flow of fluid relative to the intake valve and a second position where the intake valve allows a flow of fluid relative to the intake valve. A cam assembly is configured to move the intake valve between the first position and the second position. A fluid actuator having a chamber is adapted to selectively prevent the intake valve from moving to the first position. A fluid supply system is adapted to deliver fluid to the chamber of the fluid actuator. A pressure sensor is operatively engaged with the fluid supply system and is adapted to sense the pressure of the fluid within the fluid supply system. A controller is adapted to receive the sensed pressure of the fluid within the fluid supply system, to determine an expected pressure of the fluid within the fluid supply system, to identify when the sensed pressure deviates from the expected pressure, and to generate a responsive fault signal.

Claims

1. An engine valve actuation system, comprising:

an intake valve moveable between a first position where the intake valve prevents a flow of fluid relative to the intake valve and a second position where the intake valve allows a flow of fluid relative to the intake valve;

a cam assembly configured to move the intake valve between the first position and the second position;

a fluid actuator having a chamber and being adapted to selectively prevent the intake valve from moving in response to the cam assembly to the first position;

a fluid supply system adapted to deliver fluid to the chamber of the actuator;

a pressure sensor operatively engaged with the fluid supply system and adapted to sense the pressure of the fluid within the fluid supply system; and

a controller adapted to receive the sensed pressure of the fluid within the fluid supply system, to determine an expected pressure of the fluid within the fluid supply system, to identify when the sensed pressure deviates from the expected pressure, and to generate a responsive fault signal.

2. The system of claim 1, wherein the fluid supply system includes a fluid rail and the pressure sensor is operatively engaged with the fluid rail.

3. The system of claim 1, further including:

a gallery in fluid connection with the fluid supply system; and

a second pressure sensor operatively engaged with the gallery and adapted to sense the pressure of the fluid within the gallery.

4. The system of claim 3, wherein the controller determines the expected pressure as a function of a maximum sensed pressure of the fluid within the gallery.

5. The system of claim 4, wherein the controller generates a warning when the sensed pressure is less than the maximum sensed pressure of the fluid within the gallery.

6. The system of claim 1, wherein the pressure sensor senses the pressure of the fluid in the fluid supply systems at a plurality of predetermined timings.

7. The system of claim 6, wherein the controller identifies a peak pressure in the fluid supply system based on the sensed pressures of the fluid in the fluid supply system.

8. The system of claim 6, wherein the predetermined timings are selected to coincide with an expected maximum pressure being experienced in the fluid supply system.

9. The system of claim 8, wherein the predetermined timings are determined as a function of an engine speed and an end of a signal transmitted to the actuator.

10. The system of claim 8, further including a temperature sensor adapted to sense the temperature of the fluid within the fluid supply system and an engine speed sensor adapted to sense the speed of an engine.

11. The system of claim 10, wherein the predetermined timings are adjusted based on the sensed temperature of the fluid within the fluid supply system.

12. The system of claim 11, wherein the predetermined timings are determined as a function of an engine speed, an end of a signal transmitted to the actuator, and the sensed temperature of the fluid within the fluid supply system.

13. The system of claim 10, wherein the controller includes a memory adapted to store a map that defines an expected pressure pattern for the fluid supply system as a function of the fluid supply system temperature, the speed of the engine, and the end of the signal transmitted to the fluid actuator.

14. The system of claim 13, wherein the controller compares an actual pressure pattern based on the sensed pressures in the fluid supply system to an expected pressure pattern defined by the map and generates a warning signal when the actual pressure pattern is substantially different from the expected pressure pattern.

15. The system of claim 8, wherein the controller maintains a count representing a number of times that the sensed pressure at the predetermined timings deviates from the expected pressure at the predetermined timings.

16. The system of claim 15, wherein the controller generates a warning signal when the count exceeds a predetermined limit.

17. The system of claim 15, wherein the controller decreases the count when the sensed pressure at a particular predetermined timing is at or near the expected pressure for the particular predetermined timing.

18. A method of controlling an engine valve, comprising:

operating a cam assembly to move an intake valve between a first position where the intake valve prevents a flow of fluid and a second position where the intake valve allows a flow of fluid;

providing fluid through a fluid supply system to a fluid actuator to selectively prevent the intake valve from moving in response to the cam assembly to the first position;

sensing a pressure of the fluid within the fluid supply system;

determining an expected pressure of the fluid within the fluid supply system;

identifying when the sensed pressure of the fluid within the fluid supply system deviates from the expected pressure of the fluid within the fluid supply system; and

generating a fault signal when the sensed pressure deviates from the expected pressure for a predetermined period of time.

19. The method of claim 18, further including derating the engine in response to the fault signal.

20. The method of claim 18, further including sensing the pressure of fluid within a gallery adapted to supply fluid to the fluid supply system.

21. The method of claim 20, wherein the expected pressure is determined as a function of a maximum sensed pressure of the fluid within the gallery.

22. The method of claim 21, further including generating a fault signal when the sensed pressure is less than the maximum sensed pressure of the fluid within the gallery.

23. The method of claim 18, wherein the pressure of the fluid in the fluid supply system is sensed at a plurality of predetermined timings.

24. The method of claim 23, further including identifying a peak pressure in the fluid supply system based on the sensed pressures of the fluid in the fluid supply system.

25. The method of claim 23, further including selecting the predetermined timings to coincide with an expected maximum pressure being experienced in the fluid supply system.

26. The method of claim 25, further including:

sensing a speed of an engine; and

transmitting a signal to control the fluid actuator.

27. The method of claim 26, wherein the predetermined timings are determined as a function of the speed of the engine and the end of the signal transmitted to the fluid actuator.

28. The method of claim 26, further including sensing the temperature of the fluid within the fluid supply system and wherein the predetermined timings are determined as a function of the speed of the engine, an end of the signal transmitted to the actuator, and the sensed temperature of the fluid within the fluid supply system.

29. The method of claim 26, further including:

sensing a temperature of the fluid within the fluid supply system;

identifying an actual pressure pattern based on the sensed pressures of the fluid within the fluid supply system;

identifying an expected pressure pattern for the fluid supply system from a map defining the expected pressure of the fluid supply system as a function of the fluid temperature, the speed of the engine, and the end of the signal transmitted to the fluid actuator.

30. The method of claim 29, further including generating a fault signal when the actual pressure pattern is substantially different from the expected pressure pattern.

31. The method of claim 25, further including:

sensing a temperature of the fluid within the fluid supply system; and

adjusting the predetermined timings based on the sensed temperature of the fluid within the fluid supply system.

32. The method of claim 23, further including maintaining a count representing a number of times that the sensed pressure at the predetermined timings deviates from the expected pressure at the predetermined timings.

33. The method of claim 32, further including generating a fault signal when the count exceeds a predetermined limit.

34. The method of claim 32, further including decreasing the count when the sensed pressure at a selected predetermined timing is at or near the expected pressure for the selected predetermined timing.

35. An engine, comprising:

an engine block defining at least one cylinder;

a piston slidably disposed within the at least one cylinder;

an intake valve moveable between a first position where fluid is prevented from flowing relative to the intake valve and a second position where fluid is allowed to flow relative to the intake valve;

a cam assembly adapted to move the intake valve between the first position and the second position;

a fluid actuator having a chamber and being adapted to selectively prevent the intake valve from moving in response to the cam assembly to the first position;

a fluid supply system adapted to deliver fluid to the chamber of the actuator;

a pressure sensor operatively engaged with the fluid supply system and adapted to sense the pressure of the fluid within the fluid supply system; and

a controller adapted to receive the sensed pressure of the fluid within the fluid supply system, to determine an expected pressure of the fluid within the fluid supply system, to identify when the sensed pressure deviates from the expected pressure, and to generate a responsive fault signal.

36. The engine of claim 35, further including:

a crankshaft operatively connected to the piston; and

a sensor adapted to sense a rotational position of the crankshaft.

37. The engine of claim 35, wherein the fluid supply system includes a fluid rail and the pressure sensor is operatively engaged with the fluid rail.

38. The engine of claim 35, further including:

a gallery in fluid connection with the fluid supply system; and

a second pressure sensor operatively engaged with the gallery and adapted to sense the pressure of the fluid within the gallery.

39. The engine of claim 38, wherein the controller determines the expected pressure as a function of a maximum sensed pressure of the fluid within the gallery.

40. The engine of claim 39, wherein the controller generates a fault signal when the sensed pressure is less than the maximum sensed pressure of the fluid within the gallery.

41. The engine of claim 35, wherein the pressure sensor senses the pressure of the fluid in the fluid supply systems at a plurality of predetermined timings.

42. The engine of claim 41, wherein the controller identifies a peak pressure in the fluid supply system based on the sensed pressures of the fluid in the fluid supply system.

43. The engine of claim 41, wherein the predetermined timings are selected to coincide with an expected maximum pressure being experienced in the fluid supply system.

44. The engine of claim 43, wherein the predetermined timings are determined as a function of an engine speed and an end of a signal transmitted to the actuator.

45. The engine of claim 43, further including a temperature sensor adapted to sense the temperature of the fluid within the fluid supply system and an engine speed sensor adapted to sense the speed of an engine.

46. The engine of claim 45, wherein the predetermined timings are adjusted based on the sensed temperature of the fluid within the fluid supply system.

47. The engine of claim 45, wherein the predetermined timings are determined as a function of an engine speed, an end of a signal transmitted to the actuator, and the sensed temperature of the fluid within the fluid supply system.

48. The engine of claim 45, wherein the controller includes a memory adapted to store a map that defines an expected pressure pattern for the fluid supply system as a function of the fluid supply system temperature, the speed of the engine, and the end of the signal transmitted to the fluid actuator.

49. The engine of claim 48, wherein the controller compares an actual pressure pattern based on the sensed pressures in the fluid supply system to an expected pressure pattern defined by the map and generates a warning signal when the actual pressure pattern is substantially different from the expected pressure pattern.

50. The engine of claim 43, wherein the controller maintains a count representing a number of times that the sensed pressure at the predetermined timings deviates from the expected pressure at the predetermined timings.

51. The engine of claim 50, wherein the controller generates a fault signal when the count exceeds a predetermined limit.

52. The engine of claim 50, wherein the controller decreases the count when the sensed pressure at a particular predetermined timing is at or near the expected pressure for the particular predetermined timing.