FR2817311A1 - Motor vehicle has device for computing temperature of automated coupling and/or gearbox from energy input or power derived from torque and revolution rate values - Google Patents

Abstract

The device has a control unit that computes an energy input or a power using torque and revolution rate values and derives the temperature of the clutch or gearbox therefrom. The temperature of a drive motor or part thereof, e.g. the coolant temperature or the engine oil temperature, is also used to derive the temperature. Independent claims are also included for the following: a method of computing a temperature, a motor vehicle with an automated coupling and a method of controlling an automated coupling.

Description

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 Motor vehicle The invention relates to a device for determining a temperature of an automated clutch and / or an automated gearbox of a motor vehicle.

 Document DE 196 02 06 discloses a device for calculating a temperature of a clutch. In the case of such devices, the temperature is determined by means of the energy provided by the friction of the clutch in a slip situation and a temperature of the clutch is deduced therefrom by calculation. However, this device can only determine the temperature if the device is on and can perform continuous calculations. If, on the other hand, the device is temporarily switched off, the thermal behavior can only be entered imprecisely after switching on the device again.

 The object of the present invention is to carry out a reliable determination of the temperature, in particular for clutches and / or gearboxes of motor vehicles, this having to be obtained without expensive temperature detectors specially provided for this.

 In the case of the aforementioned device, which comprises a control member which, by means of torque values and values of the speed of rotation, calculates an energy input or an energy or a power and, from this, determines a temperature of the clutch and / or of the gearbox, this is obtained by the fact that in order to calculate the temperature, the temperature of a drive motor or of an element of the motor is also used drive, such as the coolant temperature or the engine oil temperature.

 Thanks to the detection circuit provided in a vehicle for monitoring the vehicle engine, such as for example the coolant temperature and / or the engine oil temperature or another direct or indirect engine temperature, it is possible to obtain improved determination of the temperature of the clutch or gearbox. This can

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 be obtained by the means that these temperature values are available in the vehicle and monitor the temperatures of parts whose behavior of the change in temperature over time is similar to the behavior, over time, of the clutch or of the gearbox, so that on the basis of the behavior over time, entered, of the engine temperature, a change in the temperature of the clutch can be determined.

 It is advantageous that the temperature of a drive motor or of a component of the drive motor is used during the initialization of the determination of the temperature of the clutch and / or of the gearbox. This is advantageous because, at the start of determining the temperature, for example after switching on the ignition of the vehicle and after switching on or initializing the device according to the invention in this way, it is possible to the current engine temperature or a temperature derived therefrom for the gearbox clutch, deduce a suitable initial value from the temperature.

 It is also advantageous to use the temperature of a drive motor or a component of the drive motor to determine an initial value for determining the temperature of the clutch and / or the gearbox. .

(TM-nouv-TM-bas)/ (TM-haut-TM-bas) * (Temb-anc-Temb-bas) avec : Temb-nouv = nouvelle température à déterminer de l'embrayage ou de la boîte de vitesses ; Temb-bas = valeur inférieure de la température de l'embrayage ou de la température de la boîte de vitesses pour le calcul, par exemple 0 C ; Tu nous = nouvelle température déterminée du moteur, comme par exemple température du fluide de refroidissement ; Tu bas = valeur inférieure de la température du moteur pour le calcul, comme par exemple 0 C ;

Tu haut = valeur supérieure de la température du moteur pour le According to another inventive idea, it is interesting that the temperature of the clutch and / or of the Tbdv-new gearbox is determined, after an initialization of the device, according to: (Temb-nOUV-Temb-bas) =

(TM-new-TM-low) / (TM-high-TM-low) * (Temb-old-Temb-low) with: Temb-new = new temperature to be determined for the clutch or gearbox; Temb-bas = lower value of the clutch temperature or of the gearbox temperature for the calculation, for example 0 C; Tu nous = new determined engine temperature, such as coolant temperature; Tu bas = lower value of the engine temperature for the calculation, for example 0 C;

Tu high = upper value of the engine temperature for the

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calcul, comme par exemple 300 C ; Temb-anc == température de l'embrayage ou de la boîte de vitesses mémorisée en dernier lieu dans la dernière phase d'exploitation.

calculation, for example 300 C; Temb-anc == temperature of the clutch or gearbox stored last in the last operating phase.

(TM-nouv-TM-bas)/ (TM-anc-TM-bas) * (Temb-anc-Temb-bas) avec : Temb-nouv = nouvelle température à déterminer de l'embrayage ou de la boîte de vitesses ; Temb bas = valeur inférieure de la température de l'embrayage ou de la température de la boîte de vitesses pour le calcul, par exemple 0 C ; TM-nouv = nouvelle température déterminée du moteur, comme par exemple température du fluide de refroidissement ; TM-bas = valeur inférieure de la température du moteur pour le calcul, comme par exemple 0 C ;

Tu ans = température du moteur mémorisée en dernier lieu dans la dernière phase d'exploitation ; Temb-anc = température de l'embrayage ou de la boîte de vitesses mémorisée en dernier lieu dans la dernière phase d'exploitation. According to another idea in accordance with the invention, it is also advantageous for the temperature of the clutch and / or of the Tbdv-new gearbox to be determined, after initialization of the device, according to: (Temb-nOUV-Temb-bas ) =

(TM-new-TM-low) / (TM-old-TM-low) * (Temb-old-Temb-low) with: Temb-new = new temperature to be determined for the clutch or gearbox; Temb low = lower value of the clutch temperature or of the gearbox temperature for the calculation, for example 0 C; TM-new = new determined engine temperature, for example temperature of the coolant; TM-low = lower value of the engine temperature for the calculation, for example 0 C;

Tu ans = engine temperature stored last in the last operating phase; Temb-anc = temperature of the clutch or gearbox stored last in the last operating phase.

It is advantageous that using the temperature of the motor or a temperature of an element of the drive motor, such as for example the temperature of the coolant or the temperature of the engine oil, the duration the ignition of the vehicle is determined by the fact that the engine temperature, or the temperature of the element, measured after switching on the ignition of the vehicle, is compared with an engine temperature, or a temperature of the element, memorized before switching on the vehicle ignition and using these two values, the duration of switching off the vehicle ignition is determined by means of a table and / or a mathematical calculation
According to another idea in accordance with the invention, in the case of a motorized vehicle comprising an automated clutch with an operating member, which can be controlled by a

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 memory control for automated clutch operation, it is advantageous that a value, used by the control member, of the coefficient of friction RW is adapted, by the control member, to the physical coefficient of friction actually existing of the clutch.

 It is advantageous that the coefficient of friction employed by the control member for the control is modified as a function of the temperature of the clutch and / or of the speed of modification of the temperature of the clutch.

 It is also advantageous that the maximum modification per hour of the value of the coefficient of friction employed by the control member is limited.

 Furthermore, it is advantageous that the limitation of the clutch temperature and / or of the speed of modification of the clutch temperature can be chosen.

 The invention is explained below by way of example with the aid of exemplary embodiments shown in the figures.

 Figure 1 is a schematic representation of a motor vehicle comprising a drive motor 1 with a clutch 2 and a gearbox 3 on the drive line. Also shown are a differential 4, wheel half-shafts 5 and wheels 6 driven by the wheel half-shafts. To the wheels can be associated rotational speed detectors, not shown, which detect the rotational speeds of the wheels. These wheel speed sensors are used to enter or calculate the input speed of the gearbox. In the presence of a detection error or in the absence of these signals, it is possible, on the side of the control member, to switch to emergency operation. In the presence of all the regular signals, we have normal operation. The speed detectors can also functionally belong to other electronic components, such as for example an anti-blocking system (ABS). At least one vehicle speed and / or a gearbox rotation speed can be determined from at least one wheel rotation speed, by means of a control member 7. The drive member 1

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 can also be produced as a hybrid drive such as an electric motor, flywheel with freewheel and internal combustion engine. Clutch 2 is produced in the form of a friction clutch, it being specified that it can also be produced, for example, in the form of a magnetic powder clutch, a flap clutch or a torque converter with clutch. converter or also in the form of another clutch. The friction clutch can also be designed as a self-correcting wear take-up clutch.

 The automatic gearbox operating device 3 comprises a control member 7 and an actuator 8 which can be controlled by the control member 7. Similarly the control member 7 can control an actuator 11 for control automatic clutch 2. In Figure 1 we can see a control member 7 and an actuator 8 shown schematically. The control member 7 can be designed as an integrated control member which controls the regulation, for example of the clutch and the gearbox. In addition, an electronic motor circuit can also be integrated into the control member. Likewise, the control of the clutch and of the gearbox, or of the actuators 7, 11 for operating the clutch and of the gearbox can be ensured by different control members. It is also possible that the control members of the clutch, the gearbox and / or the engine control circuit are arranged separately and communicate with each other by data lines and / or of signals. In addition, the control members or the electronic members are connected by signals with detectors which transmit to the control member or to the control members the operating parameters of the current operating point. It is also possible that the control unit receives all the necessary information via data lines or via a data bus, such as for example a CAN site network bus.

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 The control unit 7 is equipped with a computer to be able to receive, process, store, call and transmit the signals and the system quantities which arrive. In addition, the control member generates control quantities and / or signals for controlling the actuators as well as for transmission to other electronic members.

 The clutch 2 is mounted on a flywheel 2a or is connected to it. The flywheel can be produced in the form of a one-piece flywheel or a divided flywheel comprising a primary mass and a secondary mass, and in this case between the individual masses of the flywheel, such as between the primary mass and the secondary mass, is arranged a device for damping torsional vibrations.

In addition, a starter ring gear 2b can be arranged on the flywheel. The clutch has a clutch disc 2c comprising friction linings and a pressure plate 2d as well as a clutch cover 2e and a disc spring 2f.

The self-correcting clutch also has means which allow adjustment to be made and wear to be taken up, it being specified that there is a detector, such as a travel force detector or a rotation angle detector, which detects a situation in which a resumption of adjustment is necessary as a result for example of wear and automatically executed during this detection.

 The clutch is maneuvered by means of a declutching member 9, comprising for example a declutching surface 10.

The control member 7 controls the actuator 11 which performs the operation of the clutch. The disengagement member can be operated by electromotive, electro-hydraulic means, such as for example under the action of a pressurized fluid, such as a hydraulic fluid, or by means of another operating mechanism. The declutching member 9 comprising the declutching surface 10 can be designed in the form of a central declutching member arranged coaxially with the input shaft of the gearbox and the clutch can be engaged and disengaged for example by intervention of the clutch disc spring tabs.

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Mais l'organe de débrayage peut également être réalisé sous forme d'un organe de débrayage mécanique qui manoeuvre, contraint ou dessert une portée d'organe de débrayage ou un élément comparable.

However, the declutching member can also be produced in the form of a mechanical declutching member which operates, constrains or serves a bearing of the declutching member or a comparable element.

 The actuator 8 maneuvers, in particular with its output or maneuvering element, of which there is at least one, or with several output or maneuvering elements, the gearbox 3 for shifting a gear and / or for selecting it . The gear change and / or selection command depends on the type of gearbox.

 In particular, it is necessary to examine the case of gearboxes with a central shaft in which a gear change or gear selection process is carried out by means of an axial maneuver or a maneuver in the peripheral direction of the shaft. central of the gearbox or vice versa. For example, by means of an operating element, the actuator ensures the operation of the central shaft of the gearbox in the axial direction and, by means of another operating element, it ensures the operation of the tree in the peripheral direction. The change of speed can be done in the peripheral direction and the selection maneuver, in the axial direction or vice versa.

 It is also necessary to examine the case of gearboxes with two shafts, in the case of which there is each time a shaft to shift the gear and a shaft to select the gear ratio, the two shafts being maneuvered in the peripheral direction for execute a gear shift or selection process.

 It is also necessary to examine the case of gearboxes with shifting rods in the case of which the shifting rods are maneuvered in the axial direction to shift into a gear ratio with a shifting process, a shifting process. selection is made by the choice of the rod operated.

 The transmission shafts or rods represent maneuvering elements internal to the transmission or

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 shafts maneuver these elements inside the gearbox during a maneuver. To engage, disengage or change a speed or a gear ratio, the actuator 8 maneuvers, directly or indirectly, internal maneuvering elements in the gearbox such as a central gearbox shaft, shafts or rods gearbox or other gear shifting elements.

 The control member 7 is connected to the actuator 8 via the signal link 12 so that control signals and / or detection signals or operating status signals can be exchanged, transmitted or called.

There is also the connection for signals 13 and 14 through which the control member is at least temporarily in connection for signals with other detectors or electronic members. These other electronic components may for example be the electronic circuit of the engine, the electronic circuit of the anti-blocking system or an electronic anti-skid regulation circuit. Other detectors may be detectors which generally characterize or detect the operating state of the vehicle, such as, for example, detectors of the speed of rotation of the engine or the wheels, throttle valve position detectors, position of the accelerator pedal or other detectors. The signal link 15 establishes a link with a data bus, such as for example a CAN bus, by means of which data from the vehicle systems or other electronic components can be available, since generally the electronic components are put into operation. network with each other by computers.

 An automated gearbox can be the subject of a gear change initiated by the driver of the vehicle in the sense that by means of, for example, a gear lever, a push button or another device 40 for selecting a gear. 'a speed, it emits a signal to increase or decrease the speed. A signal could also be sent for the selection of the gear to be engaged next. Correspondingly it is also possible, by means of a

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 electronic gear lever, have a signal indicating the speed in which the gearbox should be engaged.

 In another program concerning the gearbox, an automatic gearbox maneuver can be selected so that the selection of the current gear to be shifted is made according to the operating parameters and a gear change process may be operated automatically.

However, an automatic gearbox can also, for example by means of characteristic values, characteristic lines or characteristic fields and on the basis of detector signals for certain predetermined points, automatically change gear without the driver must cause this gear change.

 In addition, it is possible, for example, to shift to neutral position N in which there is no drive connection between the input and the output of the gearbox. It is also possible to select a park position P in which a park lock is produced.

This parking position can also be automatically selected, for example when the ignition key 51 is removed from the ignition lock and the running condition of the vehicle allows it. Let us mention for example the fact of removing the ignition key while the vehicle is at high speed, in this situation the parking lock should not operate automatically.

 It is also possible to place the gearbox selection member, such as the gear lever or the selector lever 40, in position M, as manual speed selection by the driver, in position D, as automatic gear change for running the vehicle, in position P, as a parking lock and / or in position N, as the neutral position. In addition, a manual gear change can be carried out, for example by means of a gear lever. In the case of an automatic clutch with a manual gearbox, the gear lever must be moved manually to each of the positions corresponding to the different speeds.

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 Preferably the vehicle is equipped with an accelerator pedal 23, or electronic load lever, the accelerator pedal 23 controlling a detector 24 by means of which the electronic circuit 20 of the engine controls or regulates for example the arrival of fuel, the instant of ignition, the instant of injection or the position of the throttle valve via the signal line 21 of the engine 1. The electronic accelerator pedal 23 with sensor 24 is connected with the electronic circuit 20 of the motor via the signal line 25. The electronic circuit 20 of the motor is connected to the control member 7 via the signal line 22. In addition an electronic control circuit 30 of the gearbox can also be connected by signals with members 7 and 20. An electromotive control of the throttle valve is advantageous for this purpose, the position of the throttle valve being controlled by means in the electronic circuit of the engine. In such systems, a direct mechanical connection with the accelerator pedal is no longer necessary or advantageous.

 The vehicle also has an engine starting device 50 which, starting from an attempt to start the engine by the driver, for example by operating the ignition key 51 in the ignition lock, controls a circuit engine electronics and a starter to start the engine.

 The automated clutch or automated gearbox controller has a processor that processes signals. It also has a memory in which data can be stored and then called up again.

 The temperature of the clutch and / or of the gearbox can advantageously be determined by means such as, for example, the temperature of the coolant or of the engine oil or another temperature is memorized when the engine is switched off. ignition of the vehicle by the driver, before the automated switch-off of the control unit. When the control unit is switched back on, the temperature value is then compared with the value, which we have at that moment, of the

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température correspondante, étant précisé qu'alors, à partir de la valeur avant la mise hors circuit Tanc et de la valeur après la remise en circuit Tnouv, la durée de mise hors circuit Thors peut être déterminée au moyen d'un modèle de la température selon une formule où un tableau : Thors = f ( anc, nouv)
Pour améliorer la précision de la détermination de la durée de mise hors circuit on peut en outre faire appel à la température extérieure Texts on a alors :

Thors = f (Tanc, Tnouv, Text)
Au moyen de la durée de mise hors circuit, la température de l'embrayage et/ou de la boîte de vitesses peut être déterminée, par exemple à l'aide de la température à l'instant de la mise hors circuit de l'appareil de commande, mémorisée dans une mémoire, et de la durée de mise hors circuit et d'un modèle de température approprié.

corresponding temperature, it being specified that then, from the value before switching off Tanc and from the value after switching back on Tnouv, the duration of switching off Thors can be determined by means of a temperature model according to a formula where an array: Thors = f (old, new)
To improve the accuracy of determining the switch-off time, the Texts outside temperature can also be called:

Thors = f (Tanc, Tnouv, Text)
By means of the switch-off time, the temperature of the clutch and / or of the gearbox can be determined, for example using the temperature at the moment of switching off the device. control, memorized in a memory, and the duration of switch-off and an appropriate temperature model.

With regard to the temperature model, reference is made to document DE 19602006, the content of which expressly belongs to the description of the present application.

 Determining the temperature of the clutch is advantageous with regard to the characteristic values of the clutch since these values are partly a function of the temperature. For example, the friction coefficient of a clutch changes as a function of the temperature of the clutch. Thus at low temperature the coefficient of friction is rather high and decreases if the temperature increases. This means that, for the same clutch position of the clutch mechanism, the torque that the clutch mechanism can transmit decreases, since this torque is a function of the clutch position and the coefficient of friction. But when the friction coefficient of a slipping clutch decreases due to an increase in temperature, the energy input becomes more important since the clutch slips more due to the decrease in the friction coefficient and that the temperature rises more.

 It is advantageous that the friction coefficient RWcde of the clutch, which is used inside the control circuit,

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p est le d'horloge du processeur ou à intervalles plus grands. R W anc Y est le coefficient de frottement de l'intervalle de temps précédemment calculé et f (Temb) représente une fonction de la température de l'embrayage, cette fonction pouvant être une fonction linéaire ou une autre fonction. is adapted to the coefficient of physical friction RWph actually present. It is particularly advantageous that this is done so that the coefficient of friction RW cde employed by the control circuit as a function of the temperature of the clutch is adjusted or adapted. This can be done by using a coefficient of friction calculated again RWnouv = RWanc + f (Temb), this can be done at each cycle

p is the clock of the processor or at greater intervals. RW anc Y is the friction coefficient of the previously calculated time interval and f (Temb) represents a function of the temperature of the clutch, this function can be a linear function or another function.

 It can also be advantageous for the maximum increment of the maximum authorized modification of the coefficient of friction R W cde to be a function of the temperature Tomb, so that at each step the maximum modification can be varied with the temperature.

This can for example be done by the fact that: maximum increment = K * Temb
This can also be done, for example, by the fact that maximum increment = A + K * dTemb / dt, so that the maximum authorized modification of the coefficient of friction per time interval is a function of the rate of modification of the temperature. A and K y are additive or multiplicative parameters which can each time be adapted to the vehicle and to the clutch used. The two adaptations can also be combined.

 The additive parameter A is interesting in the case of the preceding formula because of this fact are also possible adaptations when the temperature is stable and that therefore dTemb / dt is zero.

 Because, in the event of a thermal load on a clutch, long-term modifications of the friction linings can occur, it is advantageous, according to another idea, to continue the adaptation so that it also remains active when the temperature has returned to normal. This adaptation can be based on the modification of parameter A.

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 According to another inventive idea, it may be advantageous for the authorized modification of the coefficient of friction of RWcde to be limited as a function of the temperature of the clutch or of the gradient of the temperature dTemb / dt of the clutch.

It can for example be provided that the modification of the coefficient of friction? RW by no adaptation can be defined as follows: dTemb / dt> 0: negative limit value <? RW <0 or dTemb / dt> 0: 0 <? RW <positive limit value
The limit values can be specifically chosen there for the vehicle or for the clutch so that the adaptation takes place with steps of interesting value.

 In the presence of a coefficient of friction, used by the control circuit, too high compared to the physical coefficient of friction, the adaptation can also be recognized and executed by the fact that for example during a starting process , due to the too high coefficient of friction employed in the control circuit, it is a too high speed of rotation of the motor which is prescribed, compared to the case where the coefficient of friction RWcde is substantially comparable to the coefficient of physical friction. This excessively high speed of rotation of the engine can be detected and, by a modification of the coefficient of friction employed by the control circuit, the position of the clutch changes so that the torque supplied can be transmitted by the clutch.

 The claims filed with the application are proposed formulations without prejudice to obtaining additional protection. The Applicant reserves the right to claim yet another combination of characteristics which has so far only appeared in the description and / or in the drawings.

 References used in the subclaims draw attention to the alternative conception of the subject matter of the main claim due to the features of the respective subclaim; they should not be understood as a

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 waiver of obtaining specific, concrete protection for the combinations of characteristics of the referenced sub-claims.

 The objects of these subclaims, however, also form autonomous inventions which present an embodiment independent of the objects of the preceding subclaims.

 The invention is not limited to the example (examples) of carrying out the description. Rather, in the context of this presentation, many variants and modifications are possible, in particular variants, elements and combinations and / or materials which, for example by combining modifications of certain elements in connection with the characteristics or elements or not process described in the general description and in the embodiments as well as in the claims and contained in the drawing, can be concluded by a person skilled in the art having regard to the solution making it possible to reach the aim and lead, by characteristics which can be combined, to a new object or to new process steps or to new process sequences, also insofar as they relate to production, control and work processes.

Claims (11)

 CLAIMS 1 Method for controlling an automated clutch (2) with an operating member (7,11), which can be controlled by a control member (7) with memory for the automated operation of the clutch, characterized by the fact that a value, used by the control member (7), of the coefficient of friction RW is adapted, by the control member, to the actually existing coefficient of friction of the clutch. 2 Method according to claim 1, characterized in that the coefficient of friction employed by the control member for the control is modified as a function of the temperature of the clutch (2) and / or of the speed of modification of the clutch temperature. 3 Method according to claim 1 or 2, characterized in that the maximum modification per hour of the value of the coefficient of friction employed by the control member is limited. 4 Method according to claim 3, characterized in that the limitation of the clutch temperature and / or the speed of modification of the clutch temperature can be chosen. 5 Method according to claim 1, characterized in that, to calculate a temperature of an automated clutch and / or an automated gearbox of a motor vehicle, a control member (7) calculates, by means of values of the torque and values of the rotation speed, an energy supply or a power and, from this, determines a temperature of the clutch and / or the gearbox, and that, to calculate the temperature, use is also made of the temperature of a drive motor (1) or of an element of the drive motor, such as for example the temperature of the coolant or the temperature of the engine oil. <Desc / Clms Page number 16> 6 Method according to claim 5, characterized in that the temperature of a drive motor or of an element of the drive motor is used during the initialization of the determination of the temperature of the 'clutch (2) and / or gearbox (3). 7 Method according to claim 6, characterized in that the temperature of a drive motor or of an element of the drive motor is used to determine an initial value for determining the temperature of the 'clutch (2) and / or gearbox (3). 8 Device according to claim 7, characterized in that the temperature of the clutch (2) and / or of the gearbox (3) Tbdv-nouvelle is determined, after initialization of the device, according to: (Temb-nOUV -Temb-bas) = (TM ~ new - TM ~ low) / (TM ~ high - TM ~ low) * (Temb-anc-Temb-bas) with: Temb-new = new temperature to be determined from

 the clutch or gearbox; Temb-bas = lower value of the clutch temperature or of the gearbox temperature for the calculation, for example 0 C; TM ~ new = new determined engine temperature, for example temperature of the coolant; TM ~ low = lower value of the engine temperature for the calculation, for example 0 C; TM-high = higher value of the engine temperature for calculation, such as 300 C; Temb-anc = temperature of the clutch or gearbox stored last in the last operating phase. 9 Method according to claim 7, characterized in that the temperature of the clutch (2) and / or the gearbox (3) Tbdv-Nouv is determined, after an initialization of the device, according to: (Temb-nOUV-Temb-bas) = (TM-Nouv-TM-Bas) / (TM-anc-TM-Bas) * (Temb-anc-Temb -low) <Desc / Clms Page number 17>  with: Temb-new = new temperature to be determined for the clutch or the gearbox; Temb-bas = lower value of the clutch temperature or of the gearbox temperature for the calculation, for example 0 C; Tu nous = new determined engine temperature, such as coolant temperature; Tu bas = lower value of the engine temperature for the calculation, for example 0 C; Tu ans = engine temperature stored last in the last operating phase; Temb-anc = temperature of the clutch or gearbox stored last in the last operating phase. 10 Method according to claim 5, characterized in that using the temperature of the motor or a temperature of an element of the drive motor, such as for example the temperature of the coolant or the temperature of engine oil, the duration of switching off the ignition of the vehicle is determined by the fact that the engine temperature, or the temperature of the element, measured after switching on the ignition of the vehicle, is compared with a temperature of the engine, or a temperature of the element, memorized before switching on the ignition of the vehicle and using these two values, the duration of switching off the ignition of the vehicle is determined by means of a table and / or a mathematical calculation. 11 Motor vehicle comprising an automated clutch controlled in accordance with the method according to one of claims 1 to 10.