Method and apparatus for controlling a torque converter clutch

• US 20080076635A1
• Filed: 09/27/2006
• Published: 03/27/2008
• Est. Priority Date: 09/27/2006
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Lee, Chunhao J., Hebbale, Kumaraswamy V.
• Granted Patent: US 7,988,597 B2
• Time in Patent Office: Days
• US Class Current: 477/180
• CPC Class Codes: F16H 2059/366 Engine or motor speed
• CPC Class Codes: F16H 2061/145 for controlling slip, e.g. approaching target slip value
• CPC Class Codes: F16H 59/14 Inputs being a function of torque or torque demand
• CPC Class Codes: F16H 59/36 Inputs being a function of speed
• CPC Class Codes: F16H 61/143 using electric control means

Abstract

A method and apparatus are provided for controlling actuation of a clutch device for a torque converter operative to transmit torque between an engine and a transmission. The method comprises controlling actuation of the clutch device effective to maintain an engine speed within a predetermined speed range when a transmission input speed is less than a threshold; and, controlling actuation of the clutch device effective to maintain slippage across the torque converter substantially at a predetermined slippage level when the transmission input speed is greater than the threshold.

Claims

1. Method for controlling torque transmitted between an internal combustion engine and a torque transmission device, comprising:

controlling actuation of a torque converter clutch device effective to maintain an engine output within a predetermined range when an input to the transmission is less than a threshold; and

,

controlling actuation of the torque converter clutch device effective to maintain a relative speed across the torque converter substantially at a predetermined magnitude when the input to the transmission is greater than the threshold.

2. The method of claim 1, wherein controlling actuation of a torque converter clutch device effective to maintain an engine output comprises controlling actuation of the torque converter clutch device effective to maintain engine speed.

3. Method for controlling actuation of a clutch device for a torque converter operative to transmit torque between an engine and a transmission, comprising:

controlling actuation of the clutch device effective to maintain an engine speed within a predetermined speed range when a transmission input speed is less than a threshold; and

,

controlling actuation of the clutch device effective to maintain slippage across the torque converter substantially at a predetermined slippage level when the transmission input speed is greater than the threshold.

4. The method of claim 3, wherein controlling actuation of the clutch device effective to maintain the engine speed within the predetermined speed range when the transmission input speed is less than the threshold comprises decreasing actuation pressure of the clutch device when engine speed is substantially less than a minimum engine speed.

5. The method of claim 4, wherein controlling actuation of the clutch device effective to maintain the engine speed substantially within the predetermined speed range when the transmission input speed is less than the threshold comprises increasing actuation pressure of the clutch device when engine speed is substantially greater than a minimum engine speed.

6. The method of claim 5, wherein the minimum engine speed comprises an engine speed sufficient to provide power to a hydraulic pump for effective hydraulic pressure in the transmission.

7. The method of claim 3, wherein controlling actuation of the clutch device effective to maintain slippage across the torque converter substantially at a predetermined slippage level when the transmission input speed is greater than the threshold comprises increasing actuation pressure of the clutch device when the slippage is substantially greater than a desired slippage level.

8. The method of claim 7, wherein controlling actuation of the clutch device effective to maintain slippage across the torque converter substantially at a predetermined slippage level when the transmission input speed is greater than the threshold comprises decreasing actuation pressure of the clutch device when the slippage is substantially less than a desired slippage level.

9. The method of claim 8, wherein the desired slippage level comprises a fixed parametric difference between engine speed and the transmission input speed.

10. The method of claim 8, wherein the desired slippage level comprises a slippage level incremented by a deadband slippage level.

11. The method of claim 3, wherein controlling actuation of the clutch device effective to maintain slippage across the torque converter substantially at a slippage level comprises maintaining actuation pressure of the clutch device when the slippage level is within an allowable range of a desired slippage level.

12. The method of claim 3, further comprising engaging and actuating the clutch device based upon an operator demand for torque and an engine operating point.

13. The method of claim 12, wherein engaging and actuating the clutch device based upon the operator demand for torque and the engine operating point comprises executing a feed-forward control scheme to control actuation of the clutch device.

14. Method for controlling slippage across a torque converter operative to transmit torque from an internal combustion engine to a torque transmission device, comprising:

controlling actuation of a torque converter clutch device effective to maintain an engine speed within a predetermined speed range when a transmission input speed is less than a threshold; and

,

controlling actuation of the torque converter clutch device effective to maintain a relative speed across the torque converter substantially at a predetermined magnitude when the transmission input speed is greater than the threshold.

15. The method of claim 14, wherein controlling actuation of the torque converter clutch device effective to maintain the engine speed within the predetermined speed range when the transmission input speed is less than the threshold comprises decreasing actuation pressure of the clutch device when engine speed is substantially less than a minimum engine speed.

16. The method of claim 15, wherein controlling actuation of the clutch device effective to maintain the engine speed substantially within the predetermined speed range when the transmission input speed is less than the threshold comprises increasing actuation pressure of the clutch device when engine speed is substantially greater than a minimum engine speed.

17. The method of claim 16, wherein the minimum engine speed comprises an engine speed sufficient to provide power to a hydraulic pump for effective hydraulic pressure in the transmission.

18. The method of claim 14, wherein controlling actuation of the clutch device effective to maintain slippage across the torque converter substantially at a predetermined slippage level when the transmission input speed is greater than the threshold comprises increasing actuation pressure of the clutch device when the slippage is substantially greater than a desired slippage level.

19. The method of claim 18, wherein controlling actuation of the clutch device effective to maintain slippage across the torque converter substantially at a predetermined slippage level when the transmission input speed is greater than the threshold comprises decreasing actuation pressure of the clutch device when the slippage is substantially less than a desired slippage level.

20. The method of claim 19, wherein the desired slippage level comprises a fixed parametric difference between engine speed and the transmission input speed.

21. Powertrain, comprising:

an internal combustion engine operatively connected to a torque converter and a torque converter clutch each selectively operative to transmit engine torque to a transmission device; and

,

a control module;

adapted to monitor a plurality of sensing devices and control a plurality of actuators; and

,

adapted to execute a plurality of algorithms contained therein to effect the following steps, the algorithms comprising;

i) code to monitor signal inputs from the sensing devices and determine an engine operating point, an engine speed, an output speed of the torque converter, and, an operator demand for torque therefrom;

ii) code to engage and actuate the clutch device based upon the operator demand for torque and the engine operating point;

iii) code to actuate the clutch device effective to maintain the engine speed greater than a speed level when the engine speed is less than a threshold; and

,

iv) code to actuate the clutch device effective to maintain slippage across the torque converter substantially at a slippage level when the engine speed is greater than the threshold.