Method for controlling a motor vehicle drive train

• US 8,002,666 B2
• Filed: 01/16/2007
• Issued: 08/23/2011
• Est. Priority Date: 01/26/2006
• Status: Expired due to Fees

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Amann, Notker, Wallner, Stefan
• Primary Examiner(s): LEWIS, TISHA D
• Application Number:
  US12/096,241
• Publication Number:
  US 20080277229A1
• Time in Patent Office: 1,680 Days
• Field of Search: 477/5, 477/6, 477/8, 180/65.21, 180/65.285, 903/912, 903/946
• US Class Current: 477/8
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/383 One-way clutches or freewheel devices
• CPC Class Codes: B60K 6/40 characterised by the assembly or relative disposition of components
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 15/2054 by controlling transmissions or clutches
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• 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 20/30 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 2510/1015 Input shaft speed, e.g. turbine speed
• CPC Class Codes: B60W 2710/02 Clutches
• CPC Class Codes: B60W 2710/105 Output torque
• CPC Class Codes: B60W 30/19 Improvement of gear change, e.g. by synchronisation or smoothing gear shift
• CPC Class Codes: F16D 2500/1045 Friction clutch
• CPC Class Codes: F16D 2500/1066 Hybrid
• CPC Class Codes: F16D 2500/3065 Torque of the engine
• CPC Class Codes: F16D 2500/3161 : Signal providing information about the state of engine accessories
• CPC Class Codes: F16D 2500/50638 : Shaft speed synchronising, e.g. using engine, clutch outside transmission
• CPC Class Codes: F16D 2500/7041 : Position
• CPC Class Codes: F16D 2500/70468 : Input shaft torque
• CPC Class Codes: F16D 48/06 : Control by electric or electronic means, e.g. of fluid pressure
• CPC Class Codes: F16H 3/725 : 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
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

A method for controlling a motor vehicle drive train including a combustion engine, an electric machine and a transmission, which are coupled by a summation gear system, having two input and one output elements, and a clutch. One input element is coupled to the crankshaft of the combustion engine, the other input element is coupled to the rotor of the electric machine and the output element is coupled to the input shaft of the transmission and the clutch is arranged between two elements of the summation gear system, such that when the clutch is disengaged a speed difference between the combustion engine and the transmission input shaft is synchronized by the electric machine and, if necessary, by a controlled engagement of the clutch. To improve synchronization, at the beginning of the synchronization the clutch is brought to its contact point before the engagement of the bridging clutch.

Claims

1. A method of controlling a motor vehicle drivetrain having an internal combustion engine (2), an electric machine (3) and a transmission (4) which are coupled with one another by a summation gear system (5, 15) with two input elements (6, 7) and one output element (8) and by a bridging clutch (12) made as a friction clutch, in which a first input element is connected, in a rotationally fixed manner, to a crankshaft (9) of the combustion engine (2), a second input element is connected, in a rotationally fixed manner, to a rotor (10) of the electric machine (3) and the output element (8) is connected, in a rotationally fixed manner, to an input shaft (11) of the transmission (4), and in which the bridging clutch (12) is arranged between two elements of the summation gear system (5, 15), and the method comprising the steps of:

synchronizing with the electric machine (3), when the bridging clutch (12) is disengaged, a speed difference existing between the combustion engine (2) and the input shaft (11) of the transmission (4) and, at a beginning of the synchronization, bringing the bridging clutch (12) to a contact point before the electric machine (3) is assisted by engagement of the bridging clutch (12) by a controlled engagement of the bridging clutch (12).

2. The method according to claim 1, further comprising the step of testing, at the beginning of synchronization, whether a maximum torque (M_EM_max) of the electric machine (3) and a charge condition of an on-board electric system battery are sufficient for the synchronization and, if a result of the test is negative, the bridging clutch (12) is brought to the contact point.

3. The method according to claim 2, further comprising the step of determining, at the beginning of the synchronization, a required torque (M_GE_soll) on the input shaft (11) of the transmission (4) and, depending on the result, accordingly controlling the bridging clutch (12) such that:

if the required torque (M_GE_soll) is one of equal and close to zero, leaving the bridging clutch (12) fully disengaged;

if the required torque (M_GE_soll) is more than zero and can be applied in full by the electric machine (3), leaving the bridging clutch (12) fully disengaged, and

if the required torque (M_GE_soll) is more than zero but cannot be applied in full by the electric machine (3), bringing the bridging clutch (12) to the contact point.

4. A method of controlling a motor vehicle drive train (1) during synchronization of an internal combustion engine (2) and a transmission (4) of the drive train (1), which further includes an electric machine (3), a clutch (12) and a summation gear system (5, 15) having a first input element (6), a second input element (7) and an output element (8), the first input element (6) is rotationally fixed to a crankshaft (9) of the combustion engine (2), the second input element (7) is rotationally fixed to a rotor (10) of electric machine (3), and the output element (8) is rotationally fixed to an input shaft (11) of the transmission (4), the method comprising the steps of:

accelerating rotation of the input shaft (11) of the transmission (4) with the electric machine (3) to reduce a difference between a rotational speed of the input shaft (11) of the transmission (4) and a rotational speed of the crankshaft (9) of the combustion engine (2);

simultaneously preparing the clutch (12) for engagement while accelerating rotation of the input shaft (1); and

further accelerating rotation of the input shaft (11) of the transmission (4) by engaging the clutch (12).

5. The method according to claim 4, further comprising the step of testing, at the beginning of synchronization, whether a maximum torque (M_EM_max) of the electric machine (3) and a charge condition of an on-board electric system battery are sufficient for the synchronization and, if a result of the test is negative, preparing the clutch (12) for engagement.

6. The method according to claim 5, further comprising the step of determining, at the beginning of synchronization, a required torque (M_GE_soll) on the input shaft (11) of the transmission (4);

leaving the clutch (12) fully disengaged if the determined required torque (M_GE_soll) is substantially zero;

leaving the clutch (12) fully disengaged if the determined required torque (M_GE_soll) is more than zero and is applicable in full by the electric machine (3); and

preparing the clutch (12) by bringing the bridging clutch (12) to the contact point if the required torque (M_GE_soll) is more than zero and the electric machine (3) is incapable of supplying the determined required torque (M_GE_soll) in full.