Method and apparatus for controlling a compressor

• US 6,799,950 B2
• Filed: 04/15/2002
• Issued: 10/05/2004
• Est. Priority Date: 04/24/2001
• Status: Expired due to Term

• Current Assignee: Wabco GmbH (Wabco Holdings Incorporated)
• Original Assignee: Wabco GmbH (Wabco Holdings Incorporated)
• Inventors: Petry, Carsten, Meier, Jörg
• Primary Examiner(s): FREAY, CHARLES GRANT
• Application Number:
  US10/123,048
• Publication Number:
  US 20020187048A1
• Time in Patent Office: 904 Days
• Field of Search: 417/32, 417/12, 417/44.2, 417/53
• US Class Current: 417/12
• CPC Class Codes: B60G 13/14 having dampers accumulating utilisable energy, e.g. compressing air fluid springs with an accumulator B60G11/30
• CPC Class Codes: B60G 17/0523 Regulating distributors or valves for pneumatic springs
• CPC Class Codes: B60G 2500/205 Air-compressor operation
• CPC Class Codes: F04B 2205/05 Pressure after the pump outlet
• CPC Class Codes: F04B 2205/11 Outlet temperature
• CPC Class Codes: F04B 49/02 Stopping, starting, unloading or idling control

Abstract

A method and apparatus for controlling a compressor suitable for delivery of pressurized fluid to a pressurized fluid system, wherein the delivery of the pressurized fluid to the pressurized fluid system can be cycled on and off as a function of a temperature signal received from a temperature sensor. The delivery of pressurized fluid is turned off when the temperature signal exceeds a temperature limit value that is based on the backpressure caused by the pressurized fluid system. Time criteria can be superposed on the temperature limits for controlling the activation and deactivation of the compressor. A preferred area of application of the invention is in vehicle pneumatic suspension systems, including systems having multiple modes of operation.

Claims

1. A method for controlling a compressor for delivering pressurized fluid to a pressurized fluid system of a vehicle, the method comprising the steps of determining the temperature at said compressor, selecting a maximum temperature for said compressor, said maximum temperature being based on backpressure caused by said pressurized fluid system, deactivating said compressor when the temperature at said compressor has exceeded said maximum temperature, and selecting a maximum time period for actuation of said compressor and deactivating said compressor after said maximum time period measured from actuation of said compressor has elapsed even if the temperature of said compressor has not exceeded said maximum temperature.

2. The method according to claim 1, further comprising the steps of selecting a minimum time period for deactivation of said compressor and maintaining said compressor deactivated until said minimum time period measured from deactivation of said compressor has expired even if said compressor has cooled to said restart temperature.

3. The method according to claim 1, wherein said step of determining the temperature at said compressor is accomplished computationally by a thermal model.

4. The method according to claim 1, wherein said pressurized fluid system is a vehicle suspension system.

5. An apparatus for controlling a compressor for delivering pressurized fluid to a pressurized fluid system of a vehicle, comprising means for determining the temperature at said compressor, means for deactivating said compressor when the temperature at said compressor has exceeded a preselected maximum temperature, said maximum temperature being based on backpressure caused by said pressurized fluid system, and means for deactivating said compressor after a preselected maximum time period measured from actuation of said compressor has elapsed even if the temperature of said compressor has not exceeded said preselected maximum temperature.

6. The apparatus according to claim 5, further comprising means for maintaining said compressor deactivated until a preselected minimum time period measured from deactivation of said compressor has expired even if said compressor has cooled to said preselected restart temperature.

7. The apparatus according to claim 5, wherein said means for determining the temperature at said compressor is a temperature sensor.

8. In a pneumatic system including a compressor, a compressed air reservoir, and at least one pneumatic device, said pneumatic system having a first mode of operation of delivering compressed air from said compressor directly to said at least one pneumatic device and a second mode of operation of delivering compressed air from said compressor to said reservoir, a method for controlling said compressor, comprising the steps of:

determining the temperature at said compressor, selecting a first maximum temperature associated with said first mode of operation, selecting a second maximum temperature associated with said second mode of operation, said first and second maximum temperatures being based on backpressure caused by said pneumatic system, deactivating said compressor during said first mode of operation when the temperature at said compressor has exceeded said first maximum temperature, and deactivating said compressor during said second mode of operation when the temperature at said compressor has exceeded said second maximum temperature.

9. The method according to claim 8, further comprising the steps of selecting a first compressor restart temperature associated with said first mode of operation and actuating said compressor during said first mode of operation when said compressor has cooled to said first restart temperature.

10. The method according to claim 9, further comprising the steps of selecting a first maximum time period for actuation of said compressor in said first mode of operation and deactivating said compressor during said first mode of operation after said first maximum time period measured from actuation of said compressor has elapsed even if the temperature of said compressor has not exceeded said first maximum temperature.

11. The method according to claim 10, further comprising the steps of selecting a first minimum time period for deactivation of said compressor in said first mode of operation and maintaining said compressor deactivated during said first mode of operation until said first minimum time period measured from deactivation of said compressor has expired even if said compressor has cooled to said first restart temperature.

12. The method according to claim 8, further comprising the steps of selecting a second compressor restart temperature associated with said second mode of operation and actuating said compressor during said second mode of operation when said compressor has cooled to said second restart temperature.

13. The method according to claim 12, further comprising the steps of selecting a second maximum time period for actuation of said compressor in said second mode of operation and deactivating said compressor during said second mode of operation after said second maximum time period measured from actuation of said compressor has elapsed even if the temperature of said compressor has not exceeded said second maximum temperature.

14. The method according to claim 13, further comprising the steps of selecting a second minimum time period for deactivation of said compressor in said second mode of operation and maintaining said compressor deactivated during said second mode of operation until said second minimum time period measured from deactivation of said compressor has expired even if said compressor has cooled to said second restart temperature.

15. The method according to claim 8, wherein the second maximum temperature is lower than a maximum temperature theoretically permissible based on said backpressure.

16. The method according to claim 15, wherein said theoretically permissible maximum temperature is a temperature beyond which said compressor would sustain damage due to overheating.

17. The method according to claim 8, wherein said pneumatic system is a vehicle suspension system and said at least one pneumatic device is at least one vehicle suspension device.

18. The method according to claim 8, wherein said step of determining the temperature at said compressor is accomplished computationally by a thermal model.

19. The method according to claim 8, further comprising the step of determining the temperature at said compressor by a thermal model in the event that said temperature sensor malfunctions.

20. The method according to claim 8, further comprising the steps of selecting a first compressor restart temperature at which said compressor is actuated during said first mode of operation when said compressor has cooled to said first restart temperature and a second compressor restart temperature at which said compressor is actuated during said second mode of operation when said compressor has cooled to said second restart temperature such that the difference between said first maximum temperature and said first restart temperature is less than the difference between said second maximum temperature and said second restart temperature.

21. In a pneumatic system including a compressor, a compressed air reservoir, and at least one pneumatic device, said pneumatic system having a first mode of operation of delivering compressed air from said compressor directly to said at least one pneumatic device and a second mode of operation of delivering compressed air from said compressor to said reservoir, an apparatus for controlling said compressor, comprising:

means for determining the temperature at said compressor, means for deactivating said compressor during said first mode of operation when the temperature at said compressor has exceeded a first maximum temperature associated with said first mode of operation, and means for deactivating said compressor during said second mode of operation when the temperature at said compressor has exceeded a second maximum temperature associated with said second mode of operation, said first and second maximum temperatures being based on backpressure caused by said pneumatic system.

22. The apparatus according to claim 21, further comprising means for actuating said compressor during said first mode of operation when said compressor has cooled to a first restart temperature associated with said first mode of operation.

23. The apparatus according to claim 22, further comprising means for deactivating said compressor during said first mode of operation after a first maximum time period for actuation of said compressor in said first mode of operation measured from actuation of said compressor has elapsed even if the temperature of said compressor has not exceeded said first maximum temperature.

24. The apparatus according to claim 23, further comprising means for maintaining said compressor deactivated during said first mode of operation until a first minimum time period for deactivation of said compressor in said first mode of operation measured from deactivation of said compressor has expired even if said compressor has cooled to said first restart temperature.

25. The apparatus according to claim 21, further comprising means for actuating said compressor during said second mode of operation when said compressor has cooled to a second restart temperature associated with said second mode of operation.

26. The apparatus according to claim 25, further comprising means for deactivating said compressor during said second mode of operation after a second maximum time period for actuation of said compressor in said second mode of operation measured from actuation of said compressor has elapsed even if the temperature of said compressor has not exceeded said second maximum temperature.

27. The apparatus according to claim 26, further comprising means for maintaining said compressor deactivated during said second mode of operation until a second minimum time period for deactivation of said compressor in said second mode of operation measured from deactivation of said compressor has expired even if said compressor has cooled to said second restart temperature.

28. The apparatus according to claim 21, wherein said means for determining the temperature at said compressor is a temperature sensor.

29. In a pneumatic system including a compressor, said pneumatic system having a plurality of modes of operation for delivering compressed air, a method for controlling said compressor, said method comprising the steps of determining the temperature at said compressor, allocating a separate maximum temperature to each mode of operation of said plurality of modes of operation, said maximum temperature being based on backpressure caused by said pneumatic system, and deactivating said compressor during one of said modes of operation when the temperature at said compressor has exceeded said maximum temperature allocated to said one of said modes of operation.

30. The method according to claim 29, further comprising the steps of allocating a separate compressor restart temperature to each mode of operation of said plurality of modes of operation, and actuating said compressor deactivated during said one of said modes of operation when said compressor has cooled to said restart temperature allocated to said one of said modes of operation.

31. The method according to claim 30, further comprising the steps of allocating a separate maximum time period for actuation of said compressor to each mode of operation of said plurality of modes of operation, and deactivating said compressor during one of said modes of operation after said maximum time period allocated to said one of said modes of operation measured from actuation of said compressor has elapsed even if the temperature of said compressor has not exceeded said maximum temperature allocated to said one of said modes of operation.

32. The method according to claim 31, further comprising the steps of allocating a separate minimum time period for deactivation of said compressor to each mode of operation of said plurality of modes of operation, and maintaining said compressor deactivated during said one of said modes of operation until said minimum time period allocated to said one of said modes of operation measured from deactivation of said compressor has expired even if said compressor has cooled to said restart temperature allocated to said one of said modes of operation.

33. In a pneumatic system including a compressor, said pneumatic system having a plurality of modes of operation for delivering compressed air, an apparatus for controlling said compressor, said apparatus comprising means for determining the temperature at said compressor, means for allocating a separate maximum temperature to each mode of operation of said plurality of modes of operation, said maximum temperature being based on backpressure caused by said pneumatic system, and means for deactivating said compressor during one of said modes of operation when the temperature at said compressor has exceeded said maximum temperature allocated to said one of said modes of operation.

34. The apparatus according to claim 33, further comprising means for allocating a separate compressor restart temperature to each mode of operation of said plurality of modes of operation, and means for actuating said compressor deactivated during said one of said modes of operation when said compressor has cooled to said restart temperature allocated to said one of said modes of operation.

35. The apparatus according to claim 34, further comprising means for allocating a separate maximum time period for actuation of said compressor to each mode of operation of said plurality of modes of operation, and means for deactivating said compressor during one of said modes of operation after said maximum time period allocated to said one of said modes of operation measured from actuation of said compressor has elapsed even if the temperature of said compressor has not exceeded said maximum temperature allocated to said one of said modes of operation.

36. The apparatus according to claim 35, further comprising means for allocating a separate minimum time period for deactivation of said compressor to each mode of operation of said plurality of modes of operation, and means for maintaining said compressor deactivated during said one of said modes of operation until said minimum time period allocated to said one of said modes of operation measured from deactivation of said compressor has expired even if said compressor has cooled to said restart temperature allocated to said one of said modes of operation.