METHOD AND APPARATUS TO PERFORM ASYNCHRONOUS SHIFTS WITH ONCOMING SLIPPING CLUTCH TORQUE FOR A HYBRID POWERTRAIN SYSTEM

• US 20090118084A1
• Filed: 10/14/2008
• Published: 05/07/2009
• Est. Priority Date: 11/04/2007
• 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.
• Granted Patent: US 8,414,449 B2
• Time in Patent Office: Days
• US Class Current: 477/5
• 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: 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 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/105 of electric type
• 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 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 30/19 Improvement of gear change, e.g. by synchronisation or smoothing gear shift
• CPC Class Codes: B60W 50/04 Monitoring the functioning of the control system
• CPC Class Codes: F16H 2037/106 with switching means to provide two variator modes or ranges
• CPC Class Codes: F16H 2061/0422 by an electric machine, e.g. by accelerating or braking the input shaft
• CPC Class Codes: F16H 2306/48 Synchronising of new gear
• CPC Class Codes: F16H 61/061 using electric control means
• CPC Class Codes: F16H 63/502 for smoothing gear shifts
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A method to control a powertrain including a transmission, an engine, and an electric machine includes monitoring a desired transmission shift including an oncoming clutch, monitoring operational parameters of the powertrain, monitoring a maximum electric machine torque capacity, determining a desired output torque profile through the desired transmission shift, determining a maximum electric machine torque capability profile through the desired transmission shift based upon the maximum electric machine torque capacity and the operational parameters, comparing the desired output torque profile to the maximum electric machine torque capability profile, determining a preferred oncoming clutch torque profile through the desired transmission shift based upon the comparing, and executing a clutch assisted shift based upon the preferred oncoming clutch torque profile.

Claims

1. Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member, the method comprising:

monitoring a desired transmission shift;

monitoring operational parameters of said powertrain;

monitoring a maximum electric machine torque capacity;

determining a desired output torque profile through said desired transmission shift;

determining a maximum electric machine torque capability profile through said desired transmission shift based upon said maximum electric machine torque capacity and said operational parameters;

comparing said desired output torque profile to said maximum electric machine torque capability profile;

determining a preferred oncoming clutch torque profile through said desired transmission shift based upon said comparing; and

executing a clutch assisted shift based upon said preferred oncoming clutch torque profile.

2. The method of claim 1, further comprising monitoring a clutch power limit, wherein determining said preferred oncoming clutch torque profile through said desired transmission shift is further based upon said clutch power limit.

3. The method of claim 2, wherein determining said preferred oncoming clutch torque profile through said desired transmission shift based upon said clutch power limit comprises:

determining a clutch energy profile through said desired transmission shift by integrating a product of torque transmitted through an oncoming clutch and an oncoming clutch slip speed;

comparing said clutch energy profile to said clutch power limit through said desired transmission shift; and

limiting said oncoming clutch torque profile based upon said comparing said clutch energy profile to said clutch power limit.

4. The method of claim 1, wherein said powertrain further comprises a second electric machine, wherein monitoring said maximum electric machine torque capacity comprises monitoring capabilities of said electric machines to provide torque together.

5. The method of claim 1, wherein monitoring operational parameters of said powertrain comprises:

monitoring a current engine output;

monitoring a current input speed of an input member to an oncoming clutch;

monitoring a current output speed of an output member to said oncoming clutch; and

monitoring a requested output torque.

6. The method of claim 1, wherein executing said clutch assisted shift comprises:

executing an clutch assisted portion of said desired transmission shift before an oncoming clutch achieves a slip speed equal to zero; and

executing a synchronous portion of said desired transmission shift after said oncoming clutch achieves a slip speed equal to zero.

7. The method of claim 1,

wherein said desired transmission shift includes a shift to a mode operating range state, and

wherein executing said clutch assisted shift based upon said preferred oncoming clutch torque profile comprises utilizing an oncoming clutch to generate torque based upon said preferred oncoming clutch torque profile and then disengaging said oncoming clutch.

8. Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member, the method comprising:

monitoring a desired transmission shift;

determining an oncoming clutch based upon said desired transmission shift;

monitoring operation of said powertrain;

determining an output torque profile based upon said desired transmission shift and said operation of said powertrain;

determining if said electric machine can achieve said output torque profile;

if said electric machine cannot achieve said output torque profile, determining if clutch assisted operation of said oncoming clutch and said electric machine can achieve said output torque profile; and

if said clutch assisted operation of said oncoming clutch and said electric machine can achieve said output torque profile, utilizing said clutch assisted operation of said oncoming clutch and said electric machine to achieve said output torque profile.

9. The method of claim 8, wherein determining said output torque profile is based upon transitioning an input member of said oncoming clutch from an input speed synchronized to a current operating range state to a target input speed synchronized to a destination operating range state after a shift time.

10. The method of claim 8, wherein determining if said electric machine can achieve said output torque profile comprises:

determining a desired output torque profile based upon said desired transmission shift and said operation of said powertrain;

determining a maximum electric machine torque capacity based upon said operation of said powertrain;

determining a maximum electric machine torque capability profile through said desired transmission shift based upon said maximum electric machine torque capacity and said output torque profile; and

comparing said desired output torque profile to said maximum electric machine torque capability profile.

11. The method of claim 10, wherein determining if said clutch assisted operation of said oncoming clutch and said electric machine can achieve said output torque profile comprises determining an output torque deficiency profile through said desired transmission shift based upon said desired output torque profile and said maximum electric machine torque capability profile

12. The method of claim 8, further comprising if said clutch assisted operation of said oncoming clutch and said electric machine cannot achieve said output torque profile, utilizing said engine, said clutch assisted operation of said oncoming clutch, and said electric machine to achieve said output torque profile.