Systems and methods for controlling mobile machine power

• US 7,472,008 B2
• Filed: 07/23/2004
• Issued: 12/30/2008
• Est. Priority Date: 07/23/2004
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Liang, Chih Chieh, Garnett, Stephen Carl, Betz, Michael Donald, Cronin, Michael George
• Primary Examiner(s): Beaulieu; Yonel
• Application Number:
  US10/897,109
• Publication Number:
  US 20060020383A1
• Time in Patent Office: 1,621 Days
• Field of Search: 701/50, 701/93, 701/55, 477/30, 477/34, 477 42- 43, 192/103.R
• US Class Current: 701/50
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 50/10 using propulsion power supplied by engine-driven generators, e.g. generators driven by combustion engines
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2710/0677 Engine power
• CPC Class Codes: B60W 2720/10 Longitudinal speed
• CPC Class Codes: B60Y 2200/41 Construction vehicles, e.g. graders, excavators
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

A method is provided for controlling power provided by a drive train system of a mobile machine, which includes an engine that provides engine power to a generator that, in turn, provides generator power to a motor. The motor provides ground power to a travel mechanism that enables the mobile machine to travel across a terrain surface. In one embodiment, the method includes adjusting operation of the motor based on a determined ground speed of the mobile machine. Based on the adjusted motor operations, the operation of the generator is adjusted. Also, the operation of the engine is adjusted such that the engine produces an amount of engine power that meets a load demand corresponding to the adjusted operation of the generator.

Claims

1. A method for controlling power provided by a drive train system of a mobile machine, which includes an engine that provides power to a generator that, in turn, provides power to a motor, the motor providing power to a travel mechanism that enables the mobile machine to travel across a terrain surface, the method comprising:

determining the ground speed of the mobile machine;

adjusting operation of the motor based on the determined ground speed;

adjusting operation of the generator based on the adjusted operation of the motor; and

adjusting operation of the engine such that the engine produces an amount of engine power that meets a load demand corresponding to the adjusted operation of the generator.

2. The method of claim 1, wherein adjusting operation of the motor includes:

accessing a performance map stored in a control system;

determining a first level of power the motor is to produce based on the information in the performance map; and

adjusting operation of the motor such that the motor produces the first level of power based on the determined ground speed.

3. The method of claim 2, wherein adjusting operation of the generator includes:

adjusting the operation of the generator in a manner consistent with a predetermined power curve reflected in the performance map in order to provide sufficient power to allow the motor to produce the first level of power.

4. The method of claim 3, wherein the predetermined power curve is related to the determined ground speed.

5. The method of claim 2, wherein the motor is configured to operate at a second level of power when the mobile machine is traveling above a second ground speed, and wherein determining the first level of power the motor is to produce includes:

determining that the ground speed of the mobile machine is below the second ground speed;

producing a motor control signal that instructs the motor to produce the first level of power, wherein the first level of power is below the second level of power.

6. The method of claim 5, wherein the motor is configured to produce a maximum level of power when the mobile machine travels at a ground speed within a predetermined range of ground speeds including the second ground speed.

7. The method of claim 6, wherein the second level of power is the maximum level of power the motor is configured to produce.

8. The method of claim 1, further including:

creating a performance map that includes information reflecting a relationship between engine power produced by the engine and drive train power produced by the motor as a function of ground speed of the mobile machine.

9. The method of claim 8, wherein the generator and motor make up a drive train of the mobile machine and wherein creating the performance map includes:

determining one or more specifications associated with the mobile machine;

shaping a motor power curve associated with the operation of the motor based on the one or more specifications, wherein the motor power curve represents a relationship between the power produced by the motor as a function of ground speed of the mobile machine;

determining a drive train power curve associated with an expected operation of the drive train, wherein the drive train power curve follows a performance path corresponding to that of the motor power curve at lower power levels; and

storing information reflecting the motor power curve and the drive train power curve in the performance map.

10. The method of claim 8, wherein power provided to the drive train by the engine is at a power level that is reflected in the drive train power curve.

11. The method of claim 2, wherein adjusting the operation of the generator includes adjusting operation of the engine based on the first level of power produced by the motor.

12. A system for controlling ground power provided by a mobile machine, comprising:

a drive train system including a generator for receiving engine power from an engine and a motor for producing ground power to a travel mechanism that allows the mobile machine to travel across a terrain surface; and

a motor control system, included in the drive train system, for receiving speed data reflecting a ground speed of the mobile machine and for generating a motor control signal based on the ground speed,

wherein the motor provides the ground power based on the motor control signal and the motor control system uses a parameter map having information reflecting one or more relationships between engine power, ground power, and ground speed to generate the motor control signal, and wherein the engine adjusts its engine power based on the ground power produced by the motor.

13. The system of claim 12, wherein the engine adjusts its power based on a load demanded by the drive train system when providing the ground power.

14. The system of claim 12, wherein the motor control system is configured to:

determine a first level of power the motor is to produce based on the information in a performance map; and

generate the motor control signal for adjusting operation of the motor such that the motor produces a first level of ground power based on the determined ground speed.

15. The system of claim 14, wherein the generator adjusts its operations based on the first level of power produced by the motor and the engine adjust the level of engine power in response to the adjusted generator operations.

16. The system of claim 12, wherein the motor is configured to operate at a first level of ground power when the mobile machine is traveling above a first ground speed, and the motor control system is configured to:

determine that the ground speed of the mobile machine is below the first ground speed; and

produce a motor control signal that instructs the motor to produce ground power that is below the first level of ground power.

17. The system of claim 16, wherein the engine is configured to operate at a first level of engine power when the motor operates at the first level of ground power, and the engine reduces its engine power to a level below the first level of engine power when the motor produces ground power below the first level of ground power.

18. The system of claim 17, wherein the first level of engine power is equal to the maximum level of engine power the engine is configured to produce.

19. The system of claim 13, wherein the motor control system includes a performance map that includes a motor power curve associated with the operation of the motor, the power curve representing a relationship between the power produced by the motor as a function of ground speed of the mobile machine.

20. The system of claim 19, wherein the performance map further includes a drive train power curve associated with a power demand for the generator that follows a performance path similar to that of the motor power curve at various mobile machine speeds.

21. The system of claim 20, wherein the performance map further includes an engine power curve associated with the engine power produced by the engine that follows a performance path similar to that of the motor power curve at various mobile machine speeds.

22. The system of claim 12, wherein the engine produces a first level of engine power when the motor produces a first level of ground power and wherein the engine independently produces a different level of engine power when the engine receives a load demand from an auxiliary load mechanism operating in the mobile machine while the motor is producing the first level of ground power.

23. The system of claim 12, wherein the generator and engine adjust their operations based on the ground power produced by the motor.

24. The system of claim 12, wherein the motor control system generates the motor control signal based on a user request to adjust the ground speed of the mobile machine.

25. The system of claim 24, wherein the user request is provided to a master control system associated with the drive train system and the master control system provides a master control signal to the motor control system directing the motor control system to adjust the ground power produced by the motor based on the user request.

26. The system of claim 12, wherein the motor control system includes a performance map that is programmed with motor power curve data that allows the motor control system to control the amount of ground power produced by the motor based on the ground speed of the mobile machine.

27. The system of claim 26, wherein the performance map includes engine power curve data reflecting anticipated operations of the engine based on the motor power curve data.

28. A computer-readable medium including instructions for performing a method, when executed by a processor, for controlling power provided by a drive train of a mobile machine including a generator receiving engine power from an engine and a motor receiving generator power from the generator and producing ground power to a travel mechanism that allows the mobile machine to travel across a terrain surface at a certain ground speed, the method comprising:

receiving a user request to adjust the ground speed of the mobile machine;

analyzing power curve information stored in a memory device that indicates an amount of ground power the motor should produce to cause the mobile machine to travel at the requested ground speed; and

generating a motor control signal based on the power curve information,

wherein the motor control signal adjusts the ground power provided by the motor to the travel mechanism and the generator adjusts the amount of generator power provided to the motor based on the adjusted ground power, and wherein the engine independently adjusts the amount of engine power provided for the mobile machine based on a load demand produced by the generator when adjusting the generator power.

29. A system for controlling power provided in a mobile machine including a drive train that transfers engine power from an engine to ground power for a travel mechanism that allows the mobile machine to travel across a terrain surface at a certain ground speed, the system comprising:

means for determining the ground speed of the mobile machine;

means for adjusting the ground power produced by the drive train based on the determined ground speed; and

means for adjusting engine power produced by the engine based on the adjusted operation of the drive train such that the engine produces levels of engine power to the drive train that are proportional to the ground power produced by the drive train at respective ground speeds of the mobile machine.

30. A method for controlling power provided by a drive train of a mobile machine including an engine and a motor that transfers ground power to a travel mechanism that enables the mobile machine to travel across a terrain surface, the method comprising:

determining a current ground speed of the mobile machine;

adjusting an amount of ground power produced by the motor based on the current ground speed using a performance map including predefined performance curves reflecting a relationship of power and ground speeds of the mobile machine; and

adjusting an amount of engine power produced by the engine based on the adjusted amount of ground power produced by the motor such that the level of engine power produced by the engine at different ground speeds is proportional to the ground power produced by the motor.

31. A method for controlling power provided to a drive train of a mobile machine including an engine and a drive train that transfers power to a travel mechanism that enables the mobile machine to travel across a terrain surface, the method comprising:

determining the ground speed of the mobile machine;

adjusting operation of the engine based on the determined ground speed; and

adjusting operation of the drive train based on the adjusted operation of the engine such that the drive train, using a motor, produces predetermined ground power as a function of the determined ground speed.

32. A system for controlling ground power provided by a mobile machine, comprising:

an engine control system for receiving speed data reflecting a ground speed of the mobile machine and for generating an engine control signal based on the ground speed;

an engine for providing engine power based on the engine control signal; and

a drive train system including a motor, the drive train system for receiving the engine power from the engine and producing ground power to a travel mechanism that allows the mobile machine to travel across a terrain surface,

wherein the engine control system uses a parameter map having information reflecting one or more relationships between engine power, ground power, and ground speed, to generate the engine control signal.

33. A computer-readable medium including instructions for performing a method, when executed by a processor, for controlling power provided to a drive train of a mobile machine including an engine that provides engine power to a drive train that provides ground power to a travel mechanism that allows the mobile machine to travel across a terrain surface, the method comprising:

determining the ground speed of the mobile machine;

analyzing power curve information stored in a memory device that indicates an amount of engine power the engine should produce based on the determined ground speed of the mobile machine; and

generating an engine control signal based on the power curve information,

wherein the engine control signal adjusts the operation of the engine, which causes the drive train to adjust the ground power provided to the travel mechanism.