METHOD AND APPARATUS FOR CLUTCH TORQUE CONTROL IN MODE AND FIXED GEAR FOR A HYBRID POWERTRAIN SYSTEM

• US 20090111644A1
• Filed: 10/13/2008
• Published: 04/30/2009
• Est. Priority Date: 10/25/2007
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: BMW AG (Bayerische Motoren Werke AG), Daimler AG (Mercedes-Benz Group AG), GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust), Chrysler LLC (Stellantis NV)
• Inventors: Heap, Anthony H., Sah, Jy-Jen F., Kaminsky, Lawrence A.
• Granted Patent: US 8,187,145 B2
• Time in Patent Office: Days
• US Class Current: 477/5
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/445 Temperature
• 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 10/115 with planetary gears
• 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 20/40 Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers power-up or power-down of the driveline B60W30/192
• CPC Class Codes: B60W 2050/0006 Digital architecture hierarchy
• CPC Class Codes: B60W 2510/0216 Clutch engagement rate
• CPC Class Codes: B60W 2510/0671 Engine manifold pressure
• CPC Class Codes: B60W 2510/0676 Engine temperature
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2555/20 Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 2710/0605 : Throttle position
• CPC Class Codes: B60W 2710/0616 : Position of fuel or air injector
• CPC Class Codes: B60W 2710/0666 : Engine torque
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: F16H 19/06 : comprising flexible members, e.g. an endless flexible member
• 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 2342/044 : Torque transmitting capability
• CPC Class Codes: F16H 3/728 : with means to change ratio in the mechanical gearing
• CPC Class Codes: F16H 61/061 : using electric control means
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility

Abstract

A method for controlling hydraulic line pressure of a hydraulic control system in an electromechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member via selective application of a plurality of hydraulically-applied torque transfer clutches includes monitoring requirements for transmission of clutch reactive torque in one of the clutches, monitoring a hydraulic line pressure within the hydraulic control system, determining a minimum clutch torque capacity required to keep the clutch from slipping, determining a hydraulic line pressure required to create the minimum clutch torque capacity, and modulating hydraulic line pressure applied to the clutch by modulating operation of the hydraulic control system based upon the hydraulic line pressure required to create the minimum clutch torque capacity.

Claims

1. Method for controlling a hydraulic line pressure of a hydraulic control system in an electromechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member via selective application of a plurality of hydraulically-applied torque transfer clutches, said method comprising:

monitoring a current output torque of said transmission;

monitoring a requested output torque;

monitoring transmission of clutch reactive torque in each of said clutches;

determining a minimum clutch torque capacity based upon said current output torque, said requested output torque, and said clutch reactive torques; and

controlling said hydraulic line pressure by modulating operation of said hydraulic control system based upon said minimum clutch torque capacity.

2. The method of claim 1, wherein determining said minimum clutch torque capacity comprises:

determining a line pressure compensation factor based upon greater of one and a ratio of said requested output torque to said current output torque;

multiplying each said clutch reactive torque for each of said clutches by said line pressure compensation factor;

identifying a critical clutch reactive torque as a maximum of said clutch reactive torques multiplied by said line pressure compensation factor; and

determining said minimum clutch torque capacity based upon said critical clutch reactive torque.

3. The method of claim 1, wherein controlling said hydraulic line pressure applied to said clutch by modulating operation of said hydraulic control system based upon said minimum clutch torque capacity comprises:

determining a minimum required hydraulic line pressure to support clutch operation based upon said minimum clutch torque capacity; and

controlling said hydraulic line pressure applied to said clutch to be no less than said minimum required hydraulic line pressure to support clutch operation.

4. The method of claim 1, wherein controlling a hydraulic line pressure applied to said clutch by modulating operation of said hydraulic control system comprises changing a hydraulic flow into said hydraulic control system.

5. The method of claim 4, wherein controlling a hydraulic line pressure applied to said clutch by modulating operation of said hydraulic control system further comprises modulating operation of functions served by said hydraulic control system.

6. The method of claim 1, wherein modulating operation of said hydraulic control system comprises:

determining an available flow from a main hydraulic pump;

determining an available flow from an auxiliary hydraulic pump;

determining a flow consumption of functions served by said hydraulic control system;

determining an estimated hydraulic line pressure based upon said flow from said main hydraulic pump, said flow from said auxiliary hydraulic pump, and said flow consumption;

determining a desired hydraulic line pressure to fulfill functions served by said hydraulic control system;

comparing said desired hydraulic line pressure to said estimated hydraulic line pressure; and

controlling said main hydraulic pump and said auxiliary hydraulic pump based upon said comparing said desired hydraulic line pressure to said estimated hydraulic line pressure.

7. Method for controlling a hydraulic line pressure of a hydraulic control system in an electromechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member via selective application of a plurality of hydraulically-applied torque transfer clutches, said method comprising:

monitoring a current output torque of said transmission;

monitoring a requested output torque;

determining a line pressure compensation factor based upon a greater of one and a ratio of said requested output torque to said current output torque; and

controlling said hydraulic line pressure by modulating operation of said hydraulic control system based upon said line pressure compensation factor.

8. The method of claim 7, further comprising:

utilizing said line pressure compensation factor to control said hydraulic control system by boosting an available line pressure based upon said requested output torque exceeding a torque capacity.

9. The method of claim 8, wherein boosting is performed based upon said requested output torque exceeding a current torque capacity.

10. The method of claim 8, wherein boosting is performed based upon a prediction of said requested output torque exceeding said torque capacity.