Method for derating a power source to limit damage

• US 8,095,285 B2
• Filed: 06/29/2007
• Issued: 01/10/2012
• Est. Priority Date: 06/29/2007
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Schifferer, Andrew N., Tobben, Matthew A., Schweizer, Alan W.
• Primary Examiner(s): Hellner, Mark
• Assistant Examiner(s): Diacou, Ari M
• Application Number:
  US11/819,904
• Publication Number:
  US 20090000292A1
• Time in Patent Office: 1,656 Days
• Field of Search: 701/1, 701/36, 701/50, 701/51, 701/53, 701/54, 701/58, 701/100, 701/103
• US Class Current: 701/54
• CPC Class Codes: B60W 30/184 Preventing damage resulting from overload or excessive wear of the driveline
• CPC Class Codes: B60W 30/1846 Preventing of breakage of drive line components, e.g. parts of the gearing
• CPC Class Codes: B66F 17/003 for fork-lift trucks
• CPC Class Codes: E02F 9/2246 Control of prime movers, e.g. depending on the hydraulic load of work tools
• CPC Class Codes: E02F 9/24 Safety devices , e.g. for preventing overload E02F9/226 takes precedence
• CPC Class Codes: F16P 7/00 Emergency devices preventing damage to a machine or apparatus F16P1/00, F16P3/00, F16P5/00 take precedence

Abstract

A method for derating a power source to limit damage to a drive train of a machine including determining a first operational parameter associated with a power conversion unit and a second operational parameter associated with the power source, selecting, based on the first operational parameter associated with the power conversion unit and the second operational parameter associated with the power source, a power source derate value, and reducing an available power output associated with the power source according to the derate value.

Claims

1. A method for derating a power source to limit damage to a drive train of a machine, the method comprising:

determining a first operational parameter associated with a power conversion unit, wherein the first operational parameter is a torque converter speed ratio;

selecting a power source derate value based on the torque converter speed ratio; and

reducing an available power output associated with the power source according to the power source derate value.

2. The method of claim 1, further including:

determining a derate modifier value associated with the machine; and

modifying the power source derate value such that the power output associated with the power source is further reduced or increased based on the derate modifier value.

3. The method of claim 1, wherein selecting a power source derate value is further based on a second operational parameter associated with the power source, wherein the second operational parameter is a speed associated with the power source.

4. The method of claim 3, wherein the selected power source derate value is less than 100 percent when a torque converter speed ratio falls below approximately 0.9, and a speed associated with the power source exceeds a reference torque speed associated with the power source.

5. The method of claim 1, wherein the reducing step includes manipulating a fuel flow to the power source.

6. The method of claim 5, wherein the speed associated with the power source remains substantially unchanged during the reducing step.

7. The method of claim 1, wherein the available power output associated with the power source is reduced based on a desired torque reduction.

8. The method of claim 7, wherein the power source derate value is specified as a percentage of a reference torque associated with the power source.

9. The method of claim 8, further including:

determining a derate modifier value associated with the machine; and

modifying the power source derate value such that the power output associated with the power source is further reduced or increased based on the derate modifier value.

10. The method of claim 9, wherein the derate modifier value is based on at least one of a machine age, a machine time in service, a machine time to next rebuild, a machine distance traveled, and a machine cumulative energy output.

11. The method of claim 8, further including:

determining a power consumption value associated with at least one ancillary system associated with the machine; and

reducing the power source derate value such that the reduced power output associated with the power source is augmented to include an amount of power approximately equal to the power consumption value.

12. A method for controlling a drive train torque on a machine, the method comprising:

determining, based on an output speed associated with a torque converter and a speed associated with a power source, a torque converter speed ratio;

determining, based on the torque converter speed ratio and the speed associated with the engine, a power source derate value;

providing a control signal, according to the power source derate value, to derate the power source to operate on a reduced-power power curve;

determining a derate modifier value associated with a history of the machine; and

adjusting the derate of the power source based on the derate modifier value.

13. The method of claim 12, wherein the power source derate value is stored in a table of power source derate values within a control module, indexed by torque converter speed ratio and engine speed.

14. The method of claim 12, wherein the power source derate value is indicative of a percentage of a reference torque associated with the power source.

15. The method of claim 14, wherein the control signal causes a fuel control module to limit fuel to the power source such that a torque output associated with the power source is limited to the percentage of the reference torque associated with the power source.

16. The method of claim 15, wherein the speed associated with the power source remains substantially unchanged when derating the power source.

17. The method of claim 12, further including:

determining a power consumption value associated with at least one ancillary system associated with the machine; and

reducing the power source derate value by an amount approximately equal to the power consumption value.

18. A machine, comprising:

a frame;

a traction device associated with one or more drive train components;

a power source mounted to the frame and operatively connected to a power conversion unit, the power conversion unit operatively connected to the one or more traction devices; and

a control module configured to;

determine a first operational parameter associated with a power conversion unit, wherein the first operational parameter is a torque converter speed ratio;

select a power source derate value based on the torque converter speed ratio; and

reduce an available power output associated with the power source according to the derate value,

wherein a speed associated with the power source remains substantially unchanged during the reducing step.

19. The machine of claim 18, further including:

at least one ancillary system associated with the machine, wherein the control module is further configured to;

determine a power consumption value associated with the at least one ancillary system; and

reduce the power source derate value such that the reduced power output associated with the power source is augmented to include an amount of power approximately equal to the power consumption value.

20. The machine of claim 18, wherein the control module is configured to:

determine a derate modifier value associated with the machine; and

modify the power source derate value such that the power output associated with the power source is further reduced or increased based on the derate modifier value.