METHOD AND APPARATUS TO DETERMINE CLUTCH SLIPPAGE IN AN ELECTRO-MECHANICAL TRANSMISSION

• US 20090112428A1
• Filed: 10/09/2008
• Published: 04/30/2009
• Est. Priority Date: 10/26/2007
• 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: Sah, Jy-Jen F.
• Granted Patent: US 8,548,703 B2
• Time in Patent Office: Days
• US Class Current: 701/67
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/26 characterised by the motors or the generators
• 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 2240/421 Speed
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/486 Operating parameters
• 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 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 2510/0241 Clutch slip, i.e. difference between input and output speeds
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/081 Speed
• CPC Class Codes: B60W 2510/104 Output speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2710/025 Clutch slip, i.e. difference between input and output speeds
• 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: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility

Abstract

A method to determine excessive clutch slippage in a transmission coupled to an engine and an electric machine adapted to selectively transmit power to an output member through selective application of torque-transfer clutches includes monitoring rotational velocities of the electric machine, engine and output member, monitoring a transmission operating range state, determining a clutch slip based upon monitored rotational velocities for one of the torque-transfer clutches intended to be synchronized based upon the transmission operating range state, and indicating a runaway slip event if the clutch slip is in excess of a threshold slip level through a threshold slip duration.

Claims

1. Method to determine excessive clutch slippage 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 through selective application of a plurality of torque-transfer clutches, the method comprising:

monitoring rotational velocities of said electric machine, said engine, and said output member;

monitoring a transmission operating range state;

determining a clutch slip based upon said monitoring said rotational velocities for one of said torque-transfer clutches intended to be synchronized based upon said transmission operating range state; and

indicating a runaway slip event if said clutch slip is in excess of a threshold slip level through a threshold slip duration.

2. The method of claim 1, wherein indicating said runaway slip event if said clutch slip is in excess of said threshold slip level through said threshold slip duration comprises:

initiating a slip event determination when said clutch slip is in excess of said threshold slip level; and

indicating said runaway slip event if after said threshold slip duration said clutch slip remains in excess of said threshold slip level.

3. The method of claim 1, wherein indicating said runaway slip event if said clutch slip is in excess of said threshold slip level through said threshold slip duration comprises:

initiating a slip event determination when said clutch slip is in excess of said threshold slip level; and

indicating said runaway slip event if said clutch slip remains in excess of said threshold slip level throughout said threshold slip duration.

4. The method of claim 1, wherein said determining said clutch slip based upon said monitoring said rotational velocities comprises utilizing a neutral operating range state equation utilizing said rotational velocities of said electric machine, said engine, and said output member in coordination with known relationships within said transmission to determine said clutch slip.

5. The method of claim 1, further comprising monitoring rotational velocities for a second electric machine.

6. The method of claim 5, wherein said determining said clutch slip based upon said monitoring said rotational velocities comprises utilizing a neutral operating range state equation utilizing said rotational velocities of said electric machine, said second electric machine, and said output member in coordination with known relationships within said transmission to determine said clutch slip.

7. The method of claim 6, further comprising determining a second clutch slip for another one of said torque-transfer clutches intended to be synchronized based upon said transmission operating range state by utilizing a single synchronized/locked clutch equation utilizing said rotational velocities of said electric machine and said second electric machine in coordination with known relationships within said transmission to determine said second clutch slip.

8. The method of claim 7, further comprising determining clutch slips for each of the remaining ones of said torque-transfer clutches by utilizing a double synchronized/locked clutch equation utilizing said rotational velocities of said electric machine or said second electric machine in coordination with known relationships within said transmission to determine said clutch slips for each of the remaining ones of said torque-transfer clutches.

9. The method of claim 7, further comprising indicating a runaway slip event if said second clutch slip is in excess of said threshold slip level through a respective clutch threshold slip duration for the corresponding torque-transfer clutch.

10. The method of claim 6, further comprising determining clutch slips for each of the remaining ones of said torque-transfer clutches by utilizing a single synchronized/locked clutch equation utilizing said rotational velocities of said electric machine and said second electric machine in coordination with known relationships within said transmission to determine said second clutch slip.

11. The method of claim 1, further comprising commanding a clutch clip reaction to reduce said clutch slip in the event of said runaway slip event.

12. Method to determine clutch slippage in an electromechanical transmission mechanically-operatively coupled to an internal combustion engine, a first electric machine, and a second electric machine adapted to selectively transmit mechanical power to an output member through selective application of a plurality of torque-transfer clutches, the method comprising:

monitoring rotational velocities of said first electric machine, said second electric machine, said engine, and said output member;

monitoring a transmission operating range state;

determining a clutch slip based upon said monitoring said rotational velocities for each of said torque-transfer clutches intended to be locked based upon said transmission operating range state;

initiating a slip event determination when said clutch slip for one of said torque-transfer clutch intended to be locked is in excess of a threshold slip level; and

indicating a runaway slip event if after a threshold slip duration said clutch slip remains in excess of said threshold slip level.

13. The method of claim 12, wherein said determining said clutch slip based upon said monitoring said rotational velocities comprises utilizing a neutral operating range state equation utilizing said rotational velocities of said electric machine, said second electric machine, and said output member in coordination with known relationships within said transmission to determine said clutch slip.

14. The method of claim 12, further comprising commanding a clutch clip reaction to reduce said clutch slip in the event of said runaway slip event.

15. Apparatus for determining excessive clutch slippage in an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine, a first electric machine, and a second electric machine adapted to selectively transmit mechanical power to an output member through selective application of a plurality of torque-transfer clutches, the apparatus comprising:

sensors located to measure rotational velocities of said first electric machine, said second electric machine, said engine, and said output member; and

a slip indication module including programming to monitor some of said rotational velocities,

monitor a transmission operating range state,

determine a clutch slip based upon said rotational velocities for one of said torque-transfer clutches intended to be synchronized based upon said transmission operating range state, and

indicate a runaway slip event if said clutch slip is in excess of a threshold slip level through a threshold slip duration.

16. The apparatus of claim 15, wherein the slip indication module including programming to determine said clutch slip further includes a neutral operating range state equation utilizing said rotational velocities of said electric machine, said second electric machine, and said output member in coordination with known relationships within said transmission to determine said clutch slip.

17. The apparatus of claim 15, wherein said slip indication module further includes programming to command a clutch clip reaction to reduce said clutch slip in the event of said runaway slip event.