Method and control unit for a motor vehicle

• US 10,293,814 B2
• Filed: 06/07/2018
• Issued: 05/21/2019
• Est. Priority Date: 06/08/2017
• Status: Active Grant

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Buhle, Felix, Lemp, Thomas
• Primary Examiner(s): Soofi, Yazan A
• Application Number:
  US16/002,529
• Publication Number:
  US 20180354498A1
• Time in Patent Office: 348 Days
• Field of Search: 701 22
• CPC Class Codes: B60K 2006/4825 Electric machine connected or connectable to gearbox input shaft
• CPC Class Codes: B60K 6/387 Actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/026 of lock-up clutches
• CPC Class Codes: B60W 10/04 including control of propulsion units
• 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 20/40 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 2510/0275 Clutch torque
• CPC Class Codes: B60W 2710/0644 Engine speed
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60Y 2200/92 Hybrid vehicles
• CPC Class Codes: F16D 2500/10412 Transmission line of a vehicle
• CPC Class Codes: F16D 2500/1045 Friction clutch
• CPC Class Codes: F16D 2500/30415 Speed of the input shaft
• CPC Class Codes: F16D 2500/30426 Speed of the output shaft
• CPC Class Codes: F16D 2500/3067 : Speed of the engine
• CPC Class Codes: F16D 48/06 : Control by electric or electronic means, e.g. of fluid pressure
• CPC Class Codes: F16H 2061/145 : for controlling slip, e.g. approaching target slip value
• CPC Class Codes: F16H 61/143 : using electric control means
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y10S 903/914 : Actuated, e.g. engaged or disengaged by electrical, hydraulic or mechanical means

Abstract

A method for operating a motor vehicle originates from a condition in which a torque converter lockup clutch (6) or a master clutch (13) is engaged and the transmission (2) is friction-locking. The torque converter lockup clutch (6) or the master clutch (13) is then brought into a slip condition on a control side, and a prime-mover rotational speed is decoupled from a driven-end rotational speed. The torque converter lockup clutch (6) or the master clutch (13) is brought into the slip condition without reducing a pressure control of the torque converter lockup clutch (6) or the master clutch (13) and by specifying a target rotational speed or a target torque for the prime mover (1) such that a torque or a target torque is greater than a power transmission capacity of the torque converter lockup clutch (6) or the master clutch (13) and slip is built up.

Claims

1. A method for operating a motor vehicle including a prime mover (1), a driven end (3) and a transmission (2), the transmission (2) connected between the prime mover (1) and the driven end (3), the transmission (2) including a starting component (4), the starting component (4) being either a torque converter (5) with a torque converter lockup clutch (6) or a master clutch (13) that is transmission-internal or transmission-external, the method comprising:

during a condition in which the torque converter lockup clutch (6) or the master clutch (13) is engaged and the transmission (2) is friction-locking such that a rotational speed of the prime-mover (1) is coupled to a rotational speed of the driven-end (3), bringing the torque converter lockup clutch (6) or the master clutch (13) into a slip condition in response to an event requiring an increase in the rotational speed of the prime-mover (1), the rotational speed of the prime-mover (1) decoupled from the rotational speed of the driven-end (3) in the slip condition, the rotational speed of the prime-mover (1) increasing after bringing the torque converter lockup clutch (6) or the master clutch (13) into the slip condition,

wherein the torque converter lockup clutch (6) or the master clutch (13) is brought into the slip condition without reducing a pressure control for the torque converter lockup clutch (6) or the master clutch (13), the pressure control determining a power transmission capacity of the torque converter lockup clutch (6) or the master clutch (13), and

wherein the torque converter lockup clutch (6) or the master clutch (13) is brought into the slip condition by specifying a target rotational speed or a target torque for the prime mover (1) such that a torque dependent on the target rotational speed or the target torque is greater than the power transmission capacity of the torque converter lockup clutch (6) or the master clutch (13).

2. The method of claim 1, wherein the target rotational speed or the target torque is specified when a difference between a torque transmitted by the torque converter lockup clutch (6) or the master clutch (13) and the simultaneously present power transmission capacity of the torque converter lockup clutch (6) or the master clutch (13) reaches or falls below a limiting value.

3. The method of claim 1, wherein the condition in which the torque converter lockup clutch (6) or the master clutch (13) is engaged and the transmission (2) is friction-locking corresponds to a micro-slip state of the torque converter lockup clutch (6) or the master clutch (13).

4. The method of claim 1, further comprising changing the pressure control of the torque converter lockup clutch (6) or the master clutch (13) in one or more of a time-controlled manner and an event-controlled manner after:

(1) specifying the target rotational speed or the target torque;

or

(2) the torque converter lockup clutch (6) or the master clutch (13) is brought into the slip condition.

5. The method of claim 4, wherein, in order to bring about the slip condition before the change in the pressure control, the pressure control increases in a manner dependent upon one or more of a driver demand and a control-side specification.

6. The method of claim 1, wherein, in order to bring about the slip condition, the target rotational speed for the prime mover (1) is specified such that the target rotational speed ramps up and subsequently further increases in a manner dependent upon one or more of a driver demand and a control-side specification.

7. The method of claim 6, further comprising changing the pressure control of the torque converter lockup clutch (6) or the master clutch (13) in one or more of a time-controlled manner and an event-controlled manner after:

(1) specifying the target rotational speed or the target torque;

or

(2) the torque converter lockup clutch (6) or the master clutch (13) is brought into the slip condition,

wherein the target rotational speed for the prime mover (1) subsequently further increases together with the change in the pressure control.

8. The method of claim 7, wherein, in order to bring about the slip condition before the change in the pressure control, the pressure control increases in the manner dependent upon one or more of the driver demand and the control-side specification.

9. The method of claim 1, wherein the target rotational speed or the target torque is specified depending on a driver demand.

10. The method of claim 1, wherein the prime mover (1) comprises an internal combustion engine (1a) and an electric motor (1b), and a separating clutch 7 is connected between the internal combustion engine (1a) and the electric machine (1b), the method further comprising implementing the target rotational speed or the target torque to bring the torque converter lockup clutch (6) or the master clutch (13) into the slip condition solely with the electric motor (1b).

11. A transmission control unit for a motor vehicle, the transmission control unit programmed to implement the method of claim 1.

12. A transmission control unit for a motor vehicle with a prime mover (1), a driven end (3) and a transmission (2), the transmission (2) connected between the prime mover (1) and the driven end (3), the transmission (2) including a starting component (4), the starting component (4) being either a torque converter (5) with a torque converter lockup clutch (6) or a master clutch (13) that is transmission-internal or transmission-external, the transmission control unit programmed to:

during a condition in which the torque converter lockup clutch (6) or the master clutch (13) is engaged and the transmission (2) is friction-locking such that a rotational speed of the prime-mover (1) is coupled to a rotational speed of the driven-end (3), bring the torque converter lockup clutch (6) or the master clutch (13) into a slip condition on a control side in response to an event requiring an increase in the rotational speed of the prime-mover (1), the rotational speed of the prime-mover (1) decoupled from the rotational speed of the driven-end (3) in the slip condition on the control side, the rotational speed of the prime-mover (1) increasing after bringing the torque converter lockup clutch (6) or the master clutch (13) into the slip condition;

bring the torque converter lockup clutch (6) or the master clutch (13) into the slip condition on the control side without reducing a pressure control for the torque converter lockup clutch (6) or the master clutch (13), the pressure control determining a power transmission capacity of the torque converter lockup clutch (6) or the master clutch (13); and

bring the torque converter lockup clutch (6) or the master clutch (13) into the slip condition on the control side by specifying a target rotational speed or a target torque for the prime mover (1) such that a torque dependent on the target rotational speed or the target torque is greater than the power transmission capacity of the torque converter lockup clutch (6) or the master clutch (13).