Method and apparatus to control operation of a hydraulic control circuit for an electro-mechanical transmission

• US 7,556,578 B2
• Filed: 10/26/2006
• Issued: 07/07/2009
• Est. Priority Date: 10/26/2006
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company), Electronic Data Systems Corporation (Perspecta, Inc.)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Sah, Jy-Jen F., Foster, Michael D., Kothari, Aniket, Snyder, Bryan R.
• Primary Examiner(s): Wright; Dirk
• Application Number:
  US11/553,064
• Publication Number:
  US 20080103003A1
• Time in Patent Office: 985 Days
• Field of Search: 475/5, 477/3
• US Class Current: 475/5
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 2001/003 with means for cooling the electrical propulsion units
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/40 characterised by the assembly or relative disposition of components
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2240/425 Temperature
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/101 Infinitely variable gearings
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• 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 20/30 Control strategies involving selection of transmission gear ratio control of change speed gearings, together with other vehicle sub-units B60W10/10; HEV transmission gearing B60K6/36; gearings and control thereof F16H
• CPC Class Codes: B60W 2510/087 Temperature
• CPC Class Codes: B60W 2555/20 Ambient conditions, e.g. wind or rain
• CPC Class Codes: F16H 2037/0866 Power split variators with distributing differentials, with the output of the CVT connected or connectable to the output shaft
• CPC Class Codes: F16H 2037/102 the input or output shaft of the transmission is connected or connectable to two or more differentials
• CPC Class Codes: F16H 2037/104 Power split variators with one end of the CVT connected or connectable to two or more differentials
• CPC Class Codes: F16H 2037/106 with switching means to provide two variator modes or ranges
• CPC Class Codes: F16H 3/728 with means to change ratio in the mechanical gearing
• CPC Class Codes: F16H 57/0413 Controlled cooling or heating of lubricant; Temperature control therefor
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility

Abstract

A method and an apparatus for controlling an electro-mechanical transmission selectively operative in a plurality of fixed gear modes and continuously variable modes is provided. The exemplary transmission comprises first and second electrical machines and a hydraulic circuit comprising a plurality of pressure control devices and flow management valves. The method comprises monitoring an operating temperature of the electrical machines. A cooling flow rate in the hydraulic circuit effective to reduce the operating temperature of the electrical machines is determined. Availability of active cooling for each of the electrical machines is determined. Hydraulic flow in the hydraulic circuit is selectively controlled.

Claims

1. Method to control an electro-mechanical transmission comprising first and second electrical machines and a hydraulic circuit comprising a plurality of pressure control devices and flow management valves, the method comprising:

monitoring an operating temperature of the electrical machines;

determining a cooling flow rate in the hydraulic circuit effective to reduce the operating temperature of the electrical machines;

determining availability of active cooling for each of the electrical machines; and

,

selectively controlling hydraulic flow in the hydraulic circuit.

2. The method of claim 1, wherein selectively controlling hydraulic flow in the hydraulic circuit comprises:

determining a base cooling flow rate effective to cool the electrical machines; and

,

controlling hydraulic flow to achieve the base cooling flow rate.

3. The method of claim 2, further comprising determining a minimum main pressure to achieve the base cooling flow rate.

4. The method of claim 3, further comprising determining a total flow rate to the hydraulic circuit, and, selectively actuating one of the pressure control devices to effect the total flow rate at the minimum main pressure.

5. The method of claim 1, further comprising:

determining a minimum main pressure when active cooling for one of the electrical machines is available;

selectively actuating one of the pressure control devices to effect active cooling;

determining a total flow rate to the hydraulic circuit; and

,

selectively actuating one of the pressure control devices to effect the total flow rate at the minimum main pressure.

6. The method of claim 1, wherein determining the cooling flow rate in the hydraulic circuit effective to reduce the operating temperature of the electrical machines comprises determining a required cooling flow rate when the operating temperature of the electrical machines is greater than a threshold temperature.

7. The method of claim 6, wherein determining the required cooling flow rate effective to reduce the operating temperature of the electrical machines further comprises determining a flow rate to a stator of one of the electrical machines effective to reduce the stator temperature.

8. The method of claim 1, wherein determining availability of active cooling for each of the electrical machines comprises determining the flow management valves are positioned to effect operation of the electro-mechanical transmission in one of a first continuously variable operating mode and a second continuously variable operating mode.

9. Article of manufacture, comprising a storage medium having a computer program encoded therein for effecting a method to control an electro-mechanical transmission comprising first and second electrical machines and a hydraulic circuit comprising a plurality of pressure control devices and flow management valves, the computer program comprising:

code to monitor an operating temperature of the electrical machines;

code to determine a cooling flow rate in the hydraulic circuit effective to reduce the operating temperature of the electrical machines;

code to determine availability of active cooling for each of the electrical machines; and

,

code to selectively control hydraulic flow in the hydraulic circuit.

10. The article of manufacture of claim 9, wherein the code to selectively control hydraulic flow in the hydraulic circuit comprises:

code to determine a base cooling flow rate effective to cool the electrical machines; and

,

code to control hydraulic flow to achieve the base cooling flow rate.

11. The article of manufacture of claim 9, wherein the code to selectively control hydraulic flow in the hydraulic circuit comprises:

code to determine a minimum main pressure when active cooling for one of the electrical machines is available;

code to selectively actuate one of the pressure control devices to effect active cooling;

code to determine a total flow rate to the hydraulic circuit; and

,

code to selectively actuate one of the pressure control devices to effect the total flow rate at the minimum main pressure.

12. Device to transmit torque to a driveline, comprising:

first and second electrical machines and a plurality of planetary gear sets coaxially oriented about a shaft;

a plurality of torque-transfer devices selectively actuatable by a hydraulic circuit, the hydraulic circuit comprising a plurality of pressure control devices and first and second flow management valves and a plurality of pressure monitoring devices; and

,

a control system, adapted to;

i) monitor an operating temperature of the electrical machines;

ii) determine a cooling flow rate in the hydraulic circuit effective to reduce the operating temperature of the electrical machines;

iii) determine availability of active cooling for each of the electrical machines; and

,

iv) selectively control hydraulic flow in the hydraulic circuit.

13. The device of claim 12, wherein the control system adapted to selectively control hydraulic flow in the hydraulic circuit comprises the control system adapted to:

determine a base cooling flow rate effective to cool the electrical machines; and

,

control hydraulic flow to achieve the base cooling flow rate.

14. The device of claim 12, wherein the control system adapted to selectively control hydraulic flow in the hydraulic circuit comprises the control system adapted to:

determine a minimum main pressure when active cooling for one of the electrical machines is available;

selectively actuate one of the pressure control devices to effect active cooling;

determine a total flow rate to the hydraulic circuit; and

,

selectively actuate one of the pressure control devices to effect the total flow rate at the minimum main pressure.