DE102015208822A1 - A method of operating an automated disconnect clutch of a hybrid powertrain of a motor vehicle and a clutch actuation system - Google Patents

Abstract

The invention relates to a method for actuating an automated separating clutch of a hybrid drive train of a motor vehicle, in which the separating clutch (4) between an internal combustion engine (2) and an electric motor (3) of the hybrid drive train (1) is arranged and the separating clutch (4) of a clutch actuator (12) is moved along a clutch path, wherein the separating clutch (4) for starting the internal combustion engine (2) in a first phase (A) by the clutch actuator (12), which rotational movement of an actuator electric motor (14) into a linear movement of the separating clutch (4) is moved from an open state to a closed state until reaching a touch point (T) and the movement of the separating clutch (4) at the touch point (T) comes to a standstill and in a second phase (B) the separating clutch ( 4) is further closed by the clutch actuator (12) until a moment is transmitted by the separating clutch (4), by means of which the Ve internal combustion engine (2) is started. In a method in which the closing time of the separating clutch is shortened, a deceleration of the movement of the separating clutch (4) is delayed in the first phase (A), so that the touch point (T) is briefly crossed by the separating clutch (4).

Description

The invention relates to a method for actuating an automated disconnect clutch of a hybrid powertrain of a motor vehicle, wherein the separating clutch between an internal combustion engine and an electric motor of the hybrid drive train is arranged and the clutch is moved by a clutch actuator along a clutch path, wherein the separating clutch for starting the engine in a the first phase by the clutch actuator, which converts a rotational movement of an actuator electric motor into a linear movement of the separating clutch is moved from the open state to a closed state until reaching a touch point, wherein the movement of the separating clutch at the touch point comes to a halt and in a second phase the Disconnect clutch is further closed by the clutch actuator until a torque is achieved by the disconnect clutch, by means of which the internal combustion engine is started and a clutch actuation system for implementation of the procedure.

In a hybrid powertrain vehicle, drivability from two independent sources of energy, at least fuel from an internal combustion engine and electrical energy from a traction battery of an electric motor, may be overcome by conversion to mechanical energy. Hybrid drives are known in which the electric motor is in second position in series with the internal combustion engine (P2 hybrid topology). Between the internal combustion engine and the electric motor, a separating clutch is arranged, which allows a purely electric driving in the open state and transmits the torque of the internal combustion engine to the drive wheel in the closed state. Another task of the clutch is the start of the engine. For this purpose, by targeted increase of the torque of the electric motor and by closing the clutch energy transferred to the stationary engine and thus accelerated. With regard to ride comfort, the torque transmitted by the disconnect clutch must be known exactly in order to avoid unwanted vehicle accelerations, since the torque of the electric motor is simultaneously transmitted to the drive wheels. The torque transmitted by the disconnect clutch is directly dependent on the position of a clutch actuator actuating the disconnect clutch. For estimating the transmitted clutch torque, the position of the clutch actuator relative to the possible travel path of the disconnect clutch must be known on the one hand, and on the other hand a clutch characteristic (clutch torque depending on the position of the clutch actuator) must be referenced to the actuator travel. A touch point represents a closed position of the separating clutch, in which the separating clutch is closed so far that this begins to transmit a moment.

Current requirements presuppose that the disconnect clutch must be closed within a very short time to a desired torque in order to initiate a restart of the internal combustion engine very dynamically. For energetic reasons, the separating clutch is opened with a large clearance during electric driving to avoid drag losses. The closing process is divided into two phases, which in 4 are shown. The speed of the, the clutch actuator driving actuator electric motor is shown over the clutch travel. In the first phase A, the released separating clutch is moved to the touch point. This gives the possibility for a fast closing operation of the separating clutch. In phase A, the speed of the Aktorelektromotors increases at the beginning of the Kupplungsbetätigungsweges and reaches at approximately half the Tastpunktposition a vertex and lowers to reach the touch point back to zero. After completion of phase A, the disconnect clutch comes to a standstill in the touch point. In a subsequent to the phase A second phase B, the separating clutch is set to the desired restart torque. As much torque is transferred to the combustion engine that it can be started. Here, the speed of the actuator electric motor passes through the phase B with a comparable characteristic. The actuator movement takes place until the separating clutch is closed so far until the desired restart torque at the separating clutch 3 is set.

In 5 the clutch travel of the separating clutch for the two phases A and B is shown once more over time. In this case, the phase A reaches the starting point, in which then the clutch travel is kept constant, after about 130 ms, which corresponds to the achievement of the touch point. Subsequently, the Kupplungsbetätigungsweg, ie the clutch is further closed to adjust the restarting torque in a very short period of time.

The dynamic demand on the clutch system is not achieved, in particular in the first phase.

From the DE 10 2013 201 580 A1 a method for increasing a dynamics of an actuator in an actuator of a vehicle is known, in which an actuator dynamics is increased by the vehicle electrical system voltage is increased in a detection of a critical driving situation.

The invention has for its object to provide a method for actuating an automated disconnect clutch, wherein the closing time of the clutch is further minimized.

According to the invention the object is achieved in that in the first phase, a deceleration of the movement of the separating clutch is delayed, so that the touch point is run over by the separating clutch for a short time. Due to the excessive dynamics of the clutch, the first phase is completed faster, which is why the touch point is reached very quickly. In the presence of further conditions in the motor vehicle can thus faster to the second phase, i. to set the restarting moment, go over. However, due to the approached position in the region of a very flat branch of the clutch characteristic curve, the overshoot resulting from this brief increase causes only a small torque error as a result of the inaccurate positioning. On the other hand, this inaccurate position is set only for a very short period of time, which is why phase B can immediately be used to set the restarting torque. The overshoot causes the touch point to be hit with less accuracy, thereby preventing asymptotic adjustment of the touch point.

In one embodiment, parameters of a position control of the Aktorelektromotors be set to increase the speed of the Aktorelektromotors. As a result, the dynamic increase is reliably realized by a simple software measure.

In one variant, the parameters of the position control of the Aktorelektromotors be set so that during the first phase, the separating clutch from a over time almost linearly changing clutch path changes abruptly in the approximately over time constant Tastpunktposition. This jump from the linearly changing clutch actuation to the constant touchpoint position quickly reaches the position of the sensing point of the disconnect clutch. With a step response, the position controller thus provides improved dynamics.

A development of the invention relates to a clutch actuation system for a clutch of a, a hybrid powertrain having motor vehicle, wherein the clutch between an internal combustion engine and an electric motor is arranged and is actuated by a clutch actuator, which comprises an actuator, which is controlled by a clutch control unit. In a clutch actuation system in which a closing time of the disconnect clutch is minimized, the clutch control device comprises a position controller which outputs parameters for the actuation of the actuator electric motor, whereby in a first phase, the dynamics of the movement of the disconnect clutch is increased, so that before the onset of stoppage Disconnect clutch in the position of the touch point this is briefly passed over. This has the advantage that the time which elapses to set the position of the touch point of the disconnect clutch, due to the excessive dynamics which acts on the disconnect clutch, can be shortened.

Advantageously, the clutch control unit is connected to a higher-level vehicle control unit, from which the clutch control unit receives a signal to move in the first phase, the disconnect clutch from an open state to a closed state until reaching the touch point with the excessive dynamics. Thus, a higher-level control unit decides whether the disconnect clutch can be operated with excessive dynamics or not due to the handling characteristics of the hybrid vehicle.

In one embodiment, the clutch control unit adjusts a torque to be transmitted from the disconnect clutch as a function of the signal transmitted by the vehicle control unit and / or an operating state of the vehicle. The current situation on the vehicle is checked and taken into account before each setting on the clutch by the clutch control unit.

The transmission of the signal from the vehicle control unit to the clutch control unit takes place via a communication line, by means of which the clutch control unit and the vehicle control unit are connected. Due to the use of such existing in the vehicle communication lines can be dispensed with additional lines for signal transmission.

The invention allows numerous embodiments. One of them will be explained in more detail with reference to the figures shown in the drawing.

Show it:

1 a schematic diagram of a hybrid drive,

2 an embodiment of the processes of the clutch actuation at a start of the internal combustion engine,

3 1 is a representation of a comparison of an embodiment of the method according to the invention with the prior art,

4 a speed curve on the clutch actuator over the coupling path according to the prior art,

5 the change of the clutch travel over time according to the prior art.

Identical features are identified by the same reference numerals.

In 1 is a schematic diagram of a drive train 1 a hybrid vehicle shown. This powertrain 1 includes an internal combustion engine 2 and an electric motor arranged in series behind it 3 , Between the combustion engine 2 and the electric motor 3 is right behind the combustion engine 2 a separating clutch 4 arranged. internal combustion engine 2 and separating clutch 4 are over a crankshaft 5 connected with each other. The electric motor 3 has a rotatable rotor 6 and a fixed stator 5 on. The output shaft 8th the separating clutch 4 is with a gearbox 9 connected, which contains a coupling element, not shown, for example, a second clutch or a torque converter, between the electric motor 3 and the transmission 9 is arranged. The gear 9 transmits that from the internal combustion engine 2 and / or the electric motor 3 generated torque on the drive wheels 10 of the hybrid vehicle. The electric motor 3 and the gearbox 9 form a gear system 11 , which is an electromechanical clutch actuator 12 for controlling the separating clutch 4 includes. This electromechanical clutch actuator 12 has one, from a clutch control unit 13 controlled actuator electric motor 14 on. The rotary motion of the actuator electric motor 14 is from a threaded spindle 15 converted into a translational movement, with which the separating clutch 4 is moved.

The between the internal combustion engine 2 and the electric motor 3 arranged separating clutch 4 is closed to, while driving the hybrid vehicle with the, of the electric motor 3 generated torque the internal combustion engine 2 to start or during a boost operation with driving internal combustion engine 2 and electric motor 3 to drive. To ensure that when restarting the engine 2 through the electric motor 3 sufficient torque from the electric motor 3 is provided, which is both the hybrid vehicle over the drive wheels 10 Without loss of comfort moves and at the same time the engine actually starts, is a precise knowledge of a clutch characteristic of the clutch 4 required. A support point of this clutch characteristic is the touch point T, below which the position of the separating clutch 4 is to be understood, in which the friction surfaces of the input or output part of the separating clutch 4 in frictional contact with each other.

How out 2 can be seen, the control of the separating clutch is divided 4 to the start of the internal combustion engine 2 through the electromechanical clutch actuator 12 in two phases. In a first phase A, in which the opened separating clutch 4 until the touch point T is moved in the closing direction, no clutch torque is initially transmitted. In the subsequent to the phase A phase B, in which the separating clutch 4 is completely closed, that rises from the separating clutch 4 transmitting clutch torque over the Aktorweg very strong. Upon reaching a predetermined Aktorweges example, 10.5 mm is through the separating clutch 4 the restarting torque of, for example, 150 nm for the start of the internal combustion engine 2 during driving of the hybrid drive by means of the electric motor 3 reached. Is the phase A completed and has the disconnect clutch 4 reaches the touch point T, the disconnect clutch remains 4 at this touch point T at a standstill. The possibility for the fast closing process of phase B is prepared. At the same time take place during the course of phase A more processes in the drive train 1 the hybrid vehicle to prepare for the actual re-start. Once all necessary operations have been completed, a signal indicating that the preparatory operations are in the driveline will be issued 1 finished, the phase B started.

In the clutch control unit 13 of the clutch actuator 12 is a position controller 16 for adjusting a position of the actuator electric motor 14 is available. To further shorten the phase A for setting the touch point T, the parameters of the position controller become 16 at the end of phase A, so shortly before reaching the touch point T, so tuned that the actuator electric motor 14 is operated at a steadily increasing speed, as from the curve C in 3 it can be seen where the actuator position is shown over time. This results in an excessive dynamics of the separating clutch 4 , In contrast, in curve D is a control of the actuator electric motor 14 represents the state of the art. As can be seen from the curve D, the actuator electric motor 14 in the prior art, such that an asymptotic approach to the target position of the separating clutch formed by the touch point T 4 he follows. In the procedure according to the invention, the actuator electric motor 14 operated at a high speed for a longer time. This high speed is decelerated shortly before reaching the touch point, whereby an overshoot is caused by which the separating clutch 4 the position of the touch point T temporarily exceeds. Since the approached as a touch point T position in the path change only a very small torque change entails, resulting in only small moment errors due to the inaccurate due to the elevation positioning of the separating clutch 4 , Furthermore, the position of the touch point T is run over only for a very short time interval, so that subsequently the separating clutch 4 Immediately assumes the position of the touch point T and remains in this. Subsequently, the phase B is transitioned, where the restart torque of the internal combustion engine 2 by further closing the separating clutch 4 is set. By such approach of the position controller 16 is the excessive dynamics of the clutch actuator 12 and thus the separating clutch 4 is set, whereby the phase A is shortened. This makes it possible, in the presence of all other conditions that immediately after setting the touch point T without further waiting in the phase B to set the restarting torque can be passed. Due to these dynamic relations, the time of the restart of the internal combustion engine is shortened.

Whether in a hybrid vehicle, this dynamic excessive activation of the separating clutch 4 can actually be performed, it is from one, the clutch control unit 13 higher-level vehicle control unit 17 which, given the appropriate condition, a signal to the clutch control unit 13 sends, which corresponds to the operating state of the separating clutch 4 then adjusts the dynamics or drives the separating clutch according to a known from the prior art method.

The described procedure makes it possible to improve the overall dynamics of the separating clutch 4 at the restart of the internal combustion engine 2 set, whereby a fulfillment of the high dynamic requirements is achieved.

LIST OF REFERENCE NUMBERS

1

 powertrain

2

 internal combustion engine

3

 electric motor

4

 separating clutch

5

 crankshaft

6

 Rotor of the electric motor

7

 Stator of the electric motor

8th

 output shaft

9

 transmission

10

 drive wheels

11

 transmission system

12

 clutch actuator

13

 Clutch control unit

14

 Aktorelektromotor

15

 screw

16

 position controller

17

 Vehicle control unit

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102013201580 A1 [0006]

Claims (7)

Method for actuating an automated separating clutch of a Hybridant riebsstranges a motor vehicle, wherein the separating clutch ( 4 ) between an internal combustion engine ( 2 ) and an electric motor ( 3 ) of the hybrid drive train ( 1 ) is arranged and the separating clutch ( 4 ) from a clutch actuator ( 12 ) is moved along a clutch path, wherein the separating clutch ( 4 ) to the start of the internal combustion engine ( 2 ) in a first phase (A) through the clutch actuator ( 12 ), which rotates a Akto relektromotors ( 14 ) in a linear movement of the separating clutch ( 4 ) umwan delt, is moved from an open state to a closed state until reaching a touch point (T) and the movement of the separating clutch ( 4 ) comes to a standstill at the touch point (T) and in a second phase (B) the separating clutch ( 4 ) by the clutch actuator ( 12 ) is closed until it passes through the separating clutch ( 4 ) a moment is transmitted by means of which the internal combustion engine ( 2 ) is started, characterized in that in the first phase (A) a deceleration of the movement of the separating clutch ( 4 ) is delayed, so that the touch point (T) of the separating clutch ( 4 ) is briefly overrun. Method according to Claim 1, characterized in that parameters of a position control of the actuator electric motor ( 14 ) for increasing the rotational speed of the Ak gateelektromotors ( 14 ). Method according to Claim 1 or 2, characterized in that the parameters of the position control of the actuator electric motor ( 14 ) are adjusted so that during the first phase (A) the separating clutch ( 4 ) transitions from an almost linearly changing over time clutch path approximately jumped in the approximately over time constant position of the touch point (T). Clutch actuation system for a disconnect clutch of a hybrid drivetrain having motor vehicle, wherein the disconnect clutch ( 4 ) between an internal combustion engine ( 2 ) and an electric motor ( 3 ) is angeord net and by a clutch actuator ( 12 ) is actuated, which a Aktore lektromotor ( 14 ) provided by a clutch control device ( 13 ) is driving bar, characterized in that the clutch control device ( 13 ) a position controller ( 16 ), which parameter for the activation of Aktore lektromotors ( 12 ), whereby in a first phase (A) a deceleration of the movement of the separating clutch ( 4 ) is delayed, so that the touch point (T) of the separating clutch ( 4 ) is briefly run over. Clutch actuation system according to claim 4, characterized in that the clutch control device ( 13 ) with a higher-level vehicle control unit ( 17 ), from which the clutch control unit ( 17 ) receives a signal in order in the first phase (A) the separating clutch ( 4 ) from egg nem an open state to a closed state until reaching the touch point (T) to proceed with the excessive dynamics. Clutch actuation system according to claim 4 or 5, characterized in that the clutch control device ( 13 ), from the separating clutch ( 4 ) to be transmitted depending on the torque of the vehicle control unit ( 17 ) transmitted signal and / or an operating condition of the vehicle. Clutch actuation system according to claim 4, 5 or 6, characterized in that the clutch control device ( 13 ) and the vehicle control unit ( 17 ) via a communication line ( 18 ) are interconnected.

Images