CONTROL OF A POWERTRAIN FOR A HYBRID SYSTEM

• US 20120083385A1
• Filed: 09/08/2011
• Published: 04/05/2012
• Est. Priority Date: 09/30/2010
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Smith, Anthony L., Yang, Hong, Bucknor, Norman K., He, Yongsheng
• Granted Patent: US 8,758,192 B2
• Time in Patent Office: Days
• US Class Current: 477/5
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• 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 2510/081 Speed
• CPC Class Codes: B60W 2510/083 Torque
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: F02N 2300/102 Control of the starter motor speed; Control of the engine speed during cranking
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A powertrain includes a first electric motor coupled to an internal combustion engine with a ratio changing device and a second motor selectively coupled to the engine through an engine disconnect clutch, the second motor further coupled to an input shaft of a transmission. A method to control the powertrain includes monitoring a propelling torque provided by the second motor, monitoring a speed of the second motor, determining a condition of the second motor based upon the propelling torque and the speed of the second motor, selecting a control mode for the first motor based upon the condition of the second motor and controlling the first motor, the second motor, and the engine disconnect clutch based upon the control mode.

Claims

1. Method to control a powertrain comprising a first electric motor coupled to an internal combustion engine with a ratio changing device and a second motor selectively coupled to the engine through an engine disconnect clutch, the second motor further coupled to an input shaft of a transmission, the method comprising:

monitoring a propelling torque provided by the second motor;

monitoring a speed of the second motor;

determining a condition of the second motor based upon the propelling torque and the speed of the second motor;

selecting a control mode for the first motor based upon the condition of the second motor; and

controlling the first motor, the second motor, and the engine disconnect clutch based upon the control mode.

2. The method of claim 1, wherein selecting the control mode for the first motor comprises activating a first motor only flying engine start based upon comparing the propelling torque of the second motor to a maximum torque of the second motor.

3. The method of claim 1, wherein selecting the control mode for the first motor comprises activating a two motor cooperative flying engine start based upon comparing the propelling torque of the second motor to a maximum torque of the second motor.

4. The method of claim 1, wherein selecting the control mode for the first motor comprises activating a first motor increased contribution flying engine start based upon a desired vehicle maximum speed.

5. The method of claim 1, wherein selecting the control mode for the first motor comprises activating a first motor increased contribution flying engine start based upon a desirable available output torque.

6. The method of claim 1, wherein selecting the control mode for the first motor comprises activating a first motor only flying engine start based upon the second motor operating in a low torque disturbance mode;

and

further comprising operating the engine disconnect clutch in a disengaged state based upon the second motor operating in the low torque disturbance mode.

7. The method of claim 6, further comprising:

after the engine is started, utilizing the first motor to synchronize the engine to the second motor; and

engaging the engine disconnect clutch after the engine is synchronized to the second motor.

8. The method of claim 1, wherein selecting the control mode for the first motor comprises activating a first motor only flying engine start based upon a speed of the second motor being too low to support the engine start.

9. The method of claim 1, wherein selecting the control mode for the first motor comprises activating a series hybrid mode based upon the second motor operating in a creep mode.

10. The method of claim 1, wherein determining the condition of the second motor comprises determining an efficiency of operating the powertrain in a series hybrid mode;

wherein selecting the control mode for the first motor comprises activating a series hybrid mode based upon the determined efficiency.

11. The method of claim 1, further comprising:

operating the powertrain in a parallel hybrid mode; and

wherein selecting the control mode for the first motor comprises determining a first motor to second motor torque generation split.

12. The method of claim 1, further comprising:

operating the powertrain in a parallel hybrid mode; and

wherein selecting the control mode for the first motor comprises determining a first motor to second motor torque regeneration split.

13. The method of claim 1, further comprising utilizing the second motor in a regeneration mode;

and

wherein selecting the control mode for the first motor comprises activating an engine spin control mode for the first motor.

14. The method of claim 13, wherein the engine is fully disengaged.

15. The method of claim 13, wherein the engine is partially disengaged.

16. The method of claim 1, wherein determining the condition of the second motor comprises determining the second motor to be operating in a power limited region.

17. The method of claim 1, wherein determining the condition of the second motor comprises determining whether a candidate control mode for the first motor would cause the second motor to operating in a power limited region.

18. The method of claim 1, wherein controlling the second motor comprises:

monitoring an output torque request;

determining a propelling torque required to be supplied to the input shaft based upon the output torque request;

determining a compensation torque required to be supplied to the engine disconnect clutch based upon the mode of the first motor; and

commanding the second motor to generate torque according to the sum of the propelling torque and the compensation torque.

19. Method to control a powertrain comprising a first electric motor connected to an internal combustion engine with a pulley drive device and a second motor connected to the engine through an engine disconnect clutch, the second motor further connected to an input shaft of a transmission, the method comprising:

providing propelling torque to the input shaft with the second motor;

monitoring a speed of the second motor;

determining a condition of the second motor based upon the propelling torque and the speed of the second motor; and

operating a flying engine start based upon the condition of the second motor, comprising;

monitoring a cranking torque required for the flying engine start;

determining a proportion of the cranking torque to be provided by the first motor based upon the condition of the second motor; and

controlling the first motor, the second motor, and the engine disconnect clutch based upon the determined proportion.

20. System to control a powertrain comprising a first electric motor connected to an internal combustion engine with a ratio changing device and a second motor connected to the engine through an engine disconnect clutch, the second motor further connected to an input shaft of a transmission, the system comprising:

the first motor;

the second motor providing torque to the input shaft;

the engine disconnect clutch; and

a control module;

monitoring a torque provided by the second motor;

monitoring a speed of the second motor;

determining a condition of the second motor based upon the propelling torque and the speed of the second motor;

selecting a control mode for the first motor based upon the condition of the second motor; and

controlling the first motor, the second motor, and the engine disconnect clutch based upon the control mode.