Control of torque direction transition in a powershift transmission

• US 8,292,785 B2
• Filed: 06/08/2010
• Issued: 10/23/2012
• Est. Priority Date: 06/08/2010
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Walker, Ralph S., Holland, Shawn A., Feldpausch, Terry G., Riedle, Bradley D.
• Primary Examiner(s): Young, Edwin A
• Application Number:
  US12/795,800
• Publication Number:
  US 20110300991A1
• Time in Patent Office: 868 Days
• Field of Search: 477/176, 477/180, 477/181
• US Class Current: 477/176
• CPC Class Codes: F16D 2500/3069 Engine ignition switch
• CPC Class Codes: F16D 2500/50293 Reduction of vibrations
• CPC Class Codes: F16D 2500/504 Relating the engine
• CPC Class Codes: F16D 2500/5085 Coasting
• CPC Class Codes: F16D 2500/70426 Clutch slip
• CPC Class Codes: F16D 48/06 Control by electric or electronic means, e.g. of fluid pressure
• CPC Class Codes: F16H 2059/144 characterised by change between positive and negative drive line torque, e.g. torque changes when switching between coasting and acceleration
• CPC Class Codes: F16H 2059/465 Detecting slip, e.g. clutch slip ratio
• CPC Class Codes: F16H 2342/044 Torque transmitting capability
• CPC Class Codes: F16H 61/688 with two inputs, e.g. selection of one of two torque-flow paths by clutches

Abstract

A method for controlling a torque direction transition in a dual clutch transmission includes decreasing a torque capacity of a transmission input clutch when clutch slip reaches a target slip during a power-off condition, producing a subsequent power-on condition, and increasing torque capacity of said clutch when clutch slip reaches a second target slip.

Claims

1. A method for controlling a torque direction transition in a powershift transmission, comprising:

(a) during a power-off condition, decreasing a torque capacity of a transmission input clutch when clutch slip reaches a target slip;

(b) producing a subsequent power-on condition;

(c) increasing torque capacity of said clutch when clutch slip reaches a second target slip.

2. The method of claim 1, wherein the target slip is a negative slip approaching zero slip.

3. The method of claim 1, wherein the target slip is a negative slip whose magnitude avoids inducing a driveline disturbance.

4. The method of claim 1, wherein:

step (a) further comprises producing a desired torque capacity of said clutch.

5. The method of claim 1, wherein:

step (a) further comprises producing a desired torque capacity of said clutch; and

step (c) further comprises increasing torque capacity of said clutch to the desired torque capacity.

6. The method of claim 1, wherein:

step (a) further comprises decreasing said torque capacity from a desired torque capacity to a target torque capacity.

7. The method of claim 1, wherein:

step (a) further comprises decreasing torque capacity of said clutch linearly over time from a desired torque capacity to a target torque capacity.

8. The method of claim 1, wherein:

step (c) further comprises increasing torque capacity of said clutch linearly over time from a target capacity to a desired torque capacity.

9. A method for controlling a torque direction transition in a powershift transmission, comprising:

(a) producing a desired torque capacity of a transmission input clutch during a power-off condition;

(b) decreasing the torque capacity of said clutch when clutch slip reaches a target slip;

(c) producing a subsequent power-on condition;

(d) increasing torque capacity of said clutch to the desired capacity when clutch slip reaches a second target slip.

10. The method of claim 9, wherein the target slip is a negative slip approaching zero slip.

11. The method of claim 9, wherein the target slip is a negative slip whose magnitude avoids inducing a driveline disturbance.

12. The method of claim 9, wherein:

step (b) further comprises decreasing said desired torque capacity to a target torque capacity.

13. The method of claim 9, wherein:

step (b) further comprises decreasing said desired torque capacity to a target torque capacity; and

step (d) further comprises increasing said target torque capacity to the desired torque capacity.

14. The method of claim 9, wherein:

step (a) further comprises decreasing said desired torque capacity linearly over time to a target torque capacity.

15. The method of claim 9, wherein:

step (c) further comprises increasing torque capacity of said input clutch linearly over time from a target capacity to the desired torque capacity.

16. A method for controlling a torque direction transition in a powershift transmission, comprising:

(a) producing a desired torque capacity of a transmission input clutch during a power-off condition;

(b) decreasing said desired torque capacity to a target torque capacity when clutch slip reaches a target slip;

(c) producing a subsequent power-on condition;

(d) increasing said target torque capacity to the desired capacity when clutch slip reaches a second target slip.

17. The method of claim 16, wherein the target slip is a negative slip approaching zero slip.

18. The method of claim 16, wherein the target slip is a negative slip whose magnitude avoids inducing a driveline disturbance.

19. The method of claim 16, wherein:

step (b) further comprises decreasing said desired torque capacity linearly over time to said target torque capacity.

20. The method of claim 16, wherein:

step (d) further comprises increasing said target torque capacity linearly over time to said desired torque capacity.