FR2755409A1 - VEHICLE WITH AUTOMATED CLUTCH - Google Patents

Abstract

The invention relates to a vehicle 1, equipped with a device for automated actuation of the clutch 3 of the vehicle, this device cooperating with a control unit 50, which is in relation to signal transmission with an electronic anti-regulation system. skating 100, which produces a control signal when it is active in a skating situation, as well as with an operating member 15 serving to regulate the torque that can be transmitted by the clutch 3.

Description

The present invention relates to a vehicle comprising a device for

  automated actuation of a mechanism, such as a transmission and / or a torque transmission system, such as a clutch, in the drive train of this vehicle cooperating with at least one control unit, ensuring control of the automated actuation of the clutch and which is in relation to signal transmission with at least one electronic anti-skid regulation system, and with at least one operating member

  can be controlled by said control unit.

  Anti-skid regulation systems are generally known, for example from the German review "Auto & Technik" Number 1 of 1992, pages 104 to 112. In a wheel skating situation, these systems act on the engine torque by means of a throttle valve control or the braking force of the various wheels by means of an anti-lock system. Consequently, the drive energy of the wheels in slip is reduced and the slip is counterbalanced. Vehicles of this kind are known for example from the German patent DE 43 16 421 and the European patent EP 0 259 634. The European patent EP 0 259 634 describes a targeted control action of a clutch for its disengagement when a traction control system comes into action. The German patent DE 43 16 421 specifies that, in the case where an anti-skid regulation system is in action, the clutch remains in its position or is engaged or disengaged

  slowly compared to the actuation speed occurring otherwise.

  The arrangements and operating modes of the aforementioned devices in the event of the activity of an anti-skid regulation system have the drawback that on the one hand the drive link between the engine and the transmission line is open and that '' if necessary, there is no longer any drive torque and, as a result, possibly the vehicle goes into a safety critical condition when a demand for power is desired from the driver despite system activity anti-skid regulation. On the other hand, there may be a drawback when the clutch is held in its current position when an anti-slip regulation system is in action or when the clutch is closed more slowly than without the

  manifestation of an activity of an anti-skid regulation system.

  This has the disadvantage that an increase in slip is generated in the clutch area or that this slip is reduced only slowly in a targeted manner. This results, where appropriate, in increased wear and / or increased application.

  energy for example in the area of the clutch friction surfaces.

  In addition there is the drawback that, in a running situation where the anti-skid regulation system is in action and in the case of a clutch control or regulation in a position situated between the position d '' full clutch and the full disengage position, (refer to document DE 195 04847 in this regard), the two regulation or control modes (anti-skid regulation and regulation or clutch position control) counterbalance each other and regulation and control behaviors are affected by

fluctuations.

  The present invention aims to create a device associated with an automated mechanism, such as for example a clutch and / or a transmission forming part of a vehicle comprising at least one anti-skid regulation system, this device operating on the one hand so as to obtain an advantageous behavior with regard to safety and on the other hand by ensuring that the mechanism, like a clutch, is subjected to as little stress as possible (thermal stress and / or mechanical stress). In addition, an object of the invention is to create a device which at least partially remedies the drawbacks encountered in the prior art. The object of the invention is also to adapt the control behavior of the automated clutch and of the associated control unit so that the opposing disturbances of the corresponding regulation systems or

  are reduced or prevented.

  According to the invention, this problem is solved by the fact that, in the case of an automated actuation of a clutch and during the manifestation of a control signal from the traction control system highlighting an activity of that -this, the control unit controls the transmissible torque by the clutch by means of the operating member provided in the vehicle to pass this transmissible torque from the value currently established up to

a maximum value.

  In the case of a vehicle comprising a device for automated actuation of a clutch located in the engine train of the vehicle comprising a drive group, a transmission and a clutch, such as for example a friction clutch, this device cooperating with a control unit ensuring the control of the automated actuation of the clutch and which is in relation to signal transmission with sensors, and where appropriate with other electronic units, such as an electronic engine control system, a system electronic-ABS and / or an electronic anti-skid regulation system, this electronic anti-skid regulation system producing a control signal when it is active in a skating situation, as well as with an actuating member which can be controlled by the control unit with a view to actuating the clutch, this vehicle can operate in accordance with the invention, so that, during a automated actuation of the clutch and when an anti-skid control system control signal is displayed, which indicates that this anti-skid control system is in action, the control unit controls the clutch to move it from the current position

  clutch to a full clutch position.

  It is advantageous that, apart from the automated actuation of the clutch, it is also possible to control an automated actuation of the transmission by means of an operating member and a control unit acting on this operating member. An automated actuation can then be a completely automated gear change operation or else a switching and / or selection operation, desired on the part of the driver and

  produced by at least one operating member.

  Also it may be judicious that a command of the increase of the torque that can be transmitted by the clutch or of the actuation of the clutch for an adjustment of the clutch in the clutch position by means of the control unit and the operating member is effected, upon the manifestation of a control signal from the anti-skid control system indicating an activity thereof, at a speed which is equal to or greater than the speed which can be obtained in the case of a control operation without the manifestation of a control signal from the traction control system. It is particularly advisable that a command to increase the torque which can be transmitted by the clutch is carried out, when a command signal from the anti-skid control system indicating an activity is manifested, at a speed which is equal. or higher than the speed could be obtained in the case of a control operation without the manifestation of a control signal from the traction control system, also when, without the manifestation of such a control signal, the torque transmissible or position

  clutch clutch would hardly be changed.

  In addition, it may be advantageous for a control of the transmissible torque or of the clutch position of the torque transmission system to be carried out, upon the manifestation of a control signal from the anti-skid regulation system indicating an activity of the latter, at a speed which is equal to or greater than the speed obtainable during a control operation without the manifestation of a control signal from the anti-skid control system (ASR), also when, without the manifestation of such a control signal, the transmissible torque or the clutch position of the transmission transmission system

  couple would be virtually unmodified.

  It is also judicious that a command to increase the torque that can be transmitted by the clutch is carried out, during the manifestation of a control signal from the anti-skid system indicating an activity thereof, at a predetermined speed. which is equal to or greater than the speed obtainable during a control operation without the manifestation of a control signal from the traction control system, also when, without the manifestation of such a control signal, the transmissible torque or the clutch position of the clutch in the current operating range does not

  would be practically unchanged.

  In addition, it is advisable for the control unit to increase to a maximum value the torque which can be transmitted by the torque transmission system during an activity of a traction control system or else to produce a clutch of the clutch. , at least as long as there is no control signal differing from this condition

  for example during a switching process.

  It is also advisable that, when an activity of the traction control system is manifested, the control unit produces a clutch control command signal only when the rotation speed (nmot) of the engine is greater than a predetermined value. This predetermined rotational speed (motor rotational speed) can for example have an incoming limit value

  in the range between 1200 rpm and 2000 rpm.

  In this regard, it may also be advisable for the control unit to produce a clutch clutch control signal for a rotation speed nmot during the manifestation of an activity of the traction control system. engine speed greater than idling speed plus a predetermined speed (nmot> idling speed + predetermined speed). This predefined value can be

  for example between 200 rpm and 1000 rpm.

  In addition, it may be advisable in accordance with the invention for the control unit to produce a clutch control command signal of the clutch only in the case of a control signal produced and / or transmitted by the anti regulation system. -skating and that, when this control signal is manifested, the control unit acts on

  the actuator and produces a clutch of the clutch.

  It is advantageous for the control unit to produce a clutch control signal from the clutch only when a control signal is produced, produced and / or transmitted by the traction control system, and when the manifestation of a rotational speed not of the motor which is greater than a predetermined speed (nmot> predetermined speed) and that, upon the manifestation of this control signal, the control unit ensures the

  control of the operating member and the clutch of the clutch.

  In addition, it is advantageous for the control unit, after the manifestation of a control signal which indicates the activity of an anti-skid control system and / or upon the manifestation of a signal which indicates a stop. activity of a traction control system, the torque that can be transmitted by the clutch is controlled to a value adapted to the current running position. The current running position is then determined on the basis of at least one of the signals, such as those representing the engine speed, the speed at the input of the transmission, the speed at the output of the transmission, the gear engaged in the transmission, the actuation of the accelerator pedal, the running speed of the

  vehicle, engine torque and other vehicle signals.

  It is also advisable for the transmissible torque which is controlled to a value adapted to the running position to take a value which falls essentially within a range between a value

minimum and a maximum value.

  It is advantageous that the minimum value is substantially zero and that the maximum value is substantially the value that can be adjusted at the

maximum.

  According to another characteristic of the invention, during the implementation of a method for controlling a torque which can be transmitted by the clutch of a vehicle by means of an automated clutch actuation device , operating in combination with a control unit for the automated actuation of the clutch, which is in signal transmission connection with an electronic anti-skid control system, which produces a control signal when it is in action in a skating situation, as well as with an operating member which can be controlled by the control unit with a view to adjusting the torque controlled by this control unit and which can be transmitted by the clutch, it is particularly advisable that, during an automated actuation of the clutch, the control unit performs the following operations: - an analysis operation to determine the existence of a control signal indicating an activity of the regulating system anti-skid ation, - when this signal is manifested, a torque control operation which can be transmitted by the clutch by means of the operating device to shift it from the value currently set up to

  a maximum value of this transmissible torque.

  According to another feature of the invention, it may be wise to use a mechanism control method which involves

  actuation or control of a device as defined above.

  Other characteristics and advantages of the invention will be highlighted.

  evidence in the following description, given by way of example not

  limiting, with reference to the accompanying drawings in which: FIG. 1 is a schematic representation of a vehicle comprising a device according to the invention, FIG. 2 represents a diagram, and

  Figure 3 shows a flowchart.

  FIG. 1 represents a vehicle 1 comprising a drive unit 2, such as for example an internal combustion engine and / or a hybrid drive system and / or an electric motor, a torque transmission system 3, such as a clutch , and a transmission 4; following the transmission, a driving axle 5 is provided which, by means of the differential 6, drives two shafts

  leading 7a and 7b, which in turn drive the wheels 8a and 8b.

  The torque transmission system 3 is represented in the form of a friction clutch comprising a flywheel 9, a pressure plate, a clutch disc 11, a clutch release bearing 12 and a clutch release fork 13, this fork of declutching being urged by means of an actuating member 15 comprising a transmitting cylinder 16, a conduit 17 of pressurized fluid, such as a hydraulic conduit, and a receiving cylinder 18. The actuating member 15 is shown in the form of an actuator actuated by pressurized fluid and it comprises an electric motor 19, which actuates the piston 20 of the emitting cylinder by means of a transmission mechanism, not shown, so that, by means of the conduit pressurized fluid 17 and the receiving cylinder 18, the torque transmission system, such as a clutch, can be engaged and disengaged. In addition, the casing of the operating member contains the control unit 50 and its electronic circuits used to actuate and control the operating member 15, that is to say the electronic circuit of power and electronic control circuit. The actuator is provided with a breather hole 21, which is connected to a reservoir 22 of pressurized fluid. The control unit is thus integrated in the operating member 15 but it could however be installed in a separate casing. The control unit 50 also controls the

  maneuver 60 ensuring automated actuation of the transmission.

  This operating member 60 contains for example electric motors and transmission mechanisms for actuating switching elements which are located inside the transmission 4. The transmission mechanisms then convert the rotational movement of the shafts output of electric motors in an actuating movement. A transmission recognition sensor 31 is provided on the transmission 4 of the vehicle or else on the operating member 60, which detects at least the position of the report currently engaged and which transmits this indication to the transmission unit.

command 50.

  The transmission can be actuated manually by means of a gearshift lever or it can be actuated automatically by means of an operating member which can be

  controlled by a control unit.

  The vehicle i provided with an automated transmission 4 comprises a gearshift element 30, on which is disposed at least one switching intention sensor or a transmission selection sensor 32, which detects a gearshift intention from the driver or an actuation of the transmission from the

  from the driver and who transmits this information to the control unit.

  In addition, the vehicle is equipped with at least one rotation speed sensor 32, which detects the rotation speed of the output shaft of the transmission or the rotation speeds of the wheels. Also a sensor 34 is provided to detect the position of the throttle valve as well.

  a sensor 35 for detecting the speed of rotation of the motor.

  The report recognition sensor 31 detects the position of switching elements located inside the transmission or else detects the report engaged in the transmission 4 so that, by means of a signal supplied by this sensor, at least the gear engaged is recorded by the control unit 50. In addition, when using an analog sensor, it is possible to detect the movement of switching elements located inside the transmission of so as to be able

  obtain early recognition of the report which will be launched subsequently.

  Furthermore, the control unit 50 can also be formed from two or more than two control units, which can also be

  arranged in different housings.

  The operating members 15, 60 are supplied by a battery 40 so that there is permanently a current supply connection. In addition, the device has an ignition switch 41, which is generally at several levels and which is generally actuated by means of the ignition key so as to thus produce an excitation of the starter of the internal combustion engine 2 by the intermediate of the conductor 42. Via the conductor 43, a signal is further transmitted to the electronic unit of the operating member 15 so that, when the ignition system is engaged, this operating member 15 is activated. The device comprises a sensor or contactor 44, which is mounted for example on the brake pedal and which is also connected via the conductor 45 to the control unit while simultaneously exciting, via the conductor 46, by example the brake light 47. When the ignition system is not engaged, that is to say when the switch 41 is open and when the brake is actuated, there is then a closing of the switch 44 and, by via the link 45, the control unit of the operating member 15 is activated so that, when the gearshift lever is actuated and before the ignition system is engaged, it transmission system reaction may occur

  torque and the clutch can be disengaged in due course.

  The embodiment shown is not only limited to a device actuated by pressurized fluid but it is also possible to have devices operating by purely mechanical force transmission for disengaging the torque transmission system. Devices of this kind actuate a declutching device or a declutching bearing directly or via a linkage

  or through a flexible link.

  The control unit 50 of the automated torque transmission system and / or of the automated transmission is in signal transmission link with a unit 100 of a traction control system via a signal conductor 102. In addition, the control unit 50 can be in signal transmission link with a control unit 101 of an ABS anti-lock system and / or with a control unit of a traction control system. The control units are in signal transmission link with sensors and / or with other electronic units via the

  signal conductors 143, 14 and / or 105.

  When, for example, the control unit 100 of the traction control system controls a targeted actuation of the brakes and / or a targeted application of the engine torque, then this control unit 100 sends to the control unit 50 a signal indicating an activity. The control unit 50 produces on its side, upon the manifestation of this signal and upon the manifestation of an appropriate speed of rotation of the motor, a control signal which indicates

  that the traction control system is active.

  When this signal is manifested, the control unit controls the torque which can be transmitted by the torque transmission system or the clutch position of the torque transmission system in accordance with the characteristic processes which

have been described above.

  FIG. 2 represents a diagram in which the torque 201 which can be transmitted by the clutch and a signal 202 are represented as a function of time t. The signal 202 indicates whether an anti-skid control system is considered to be active by the control unit 50, as for example in the case of an activity of the anti-skid control system ASR and during the existence of a rotation speed

sufficiently large of the engine.

  In the time interval between to and tl, the ASR system is not active and the torque 201 which can be transmitted by the clutch is controlled, in the manner of a corrective torque adjustment system, at a value between zero torque and maximum torque depending on requirements and the torque currently provided by the engine. At time tl, the ASR command is activated and the torque that can be transmitted by the clutch is increased to the maximum value, which is reached at the time maximum value Between maximum value and t2, the ASR system is in action and the torque transmissible by the clutch is controlled to the maximum value. At time t2, the traction control system is deactivated and the torque transmissible 201 by the clutch is reduced to the

  value corresponding to the market situation.

  The speed at which the clutch is closed between t 1 and t maximum value is determined from a maximum value between the current speed V current and a predetermined speed V predetermined. When Vactuelle is greater than Vpredetermined, then the clutch is closed at Vactual speed until this Vactual speed is lower than Vpredetermined and then the clutch actuation system operates at speed

V predetermined.

  Curve 202 represents an ASRActive signal, signaling an activity of an anti-skid regulation system. This ASRActive signal 202 11 is equal to zero without the existence of an activity of the ASR system and, when an activity of the ASR system is manifested, it is practically different

  from zero or equal to a predetermined value, such as equal to one.

  The present invention further relates to the older German patent application DE 195 04 847 the content of which is expressly related to the disclosure content of this

patent application.

  The device according to the invention has the advantage that the slip occurring for example on a wheel is not felt or only slightly felt in the clutch and that the anti-slip regulation and actuation control units d 'clutch

  and / or transmission do not interfere strongly with each other.

  FIG. 3 represents a flow diagram 300 according to the invention for controlling the torque that can be transmitted by the clutch. In block 301, the control process is started for example in a subroutine forming part of the general control program. This engagement can be controlled by an event, such as by a signal which is produced by the control unit, for example during a comparison of wheel rotation speeds when these speeds have, in the case of a predetermined slippage, a predetermined difference between them. This process can also be questioned which is repeated at the rate of the main program. This can be done for example

every 10 ms to 100 ms.

  In box 302, the current running situation of the vehicle is determined using at least some of the data relating to the vehicle such as the engine speed, the engine torque, the speed at the input of the transmission, the rotation speed at the output of the transmission, the vehicle running speed, the position of the accelerator pedal, the transmission ratio in the transmission, the application of the brakes, etc. On the basis of this data or of these signals, which are received by means of sensors or which are determined by other electronic units and which are transmitted to the control unit, a determination is made in box 303. of the couple that can be

transmitted by the clutch.

  In box 304, the torque that can be transmitted by the clutch is established or adjusted, by means of a control signal, by the operating member. In box 305, the signal emitted by the electronic anti-skid control system is received and it indicates an activity of this anti-skid control system or no activity of this system. In block 306, this signal is analyzed and an interrogation takes place to define whether an activity of the anti-skid regulation system is manifested. If this is not the case, the program is continued in box 304. The program could also continue in box 302 or in box 303. When there is an activity, a query occurs in box 307. define if the motor rotation speed is lower than a limit value. If this is the case, the program is continued in box 304. The program can also be continued in box 302 or in box 303. When there is a rotation speed which is greater than the limit value, then in the box 308 the torque that can be transmitted by the clutch is increased to the maximum value at a speed which is at least equal to the normal actuation speed. It is

  also possible to select a maximum actuation speed.

  In box 309, an interrogation occurs to define if there is still a skating situation and / or if the anti-skid regulation system is still in action. If this is the case, the program is continued in box 308 and the clutch is still engaged or kept engaged; otherwise the program is continued in box 302 and the normal torque that can be transmitted by the clutch in the current running situation is established. If this condition manifests itself for example during an ordering process with corrective torque adjustment in a running situation where only part of the maximum transmissible torque corresponds to the engine torque, then the clutch can be partially opened again such so that, according to the corrective torque adjustment method, only a torque that can be transmitted by the clutch, like the clutch torque, is adjusted, this torque falling within a tolerance range surrounding the torque currently produced by

engine.

  The invention is also not limited to the examples of

  realization given in the description. On the contrary, in the context of

  the invention, it is possible to envisage numerous variations and modifications, in particular variants, elements and combinations and / or materials which are inventive, for example by combination or modification of certain features, or elements, or operating steps, which have summer

  described in relation to those described in the general description, the forms

  embodiments which are contained in the drawings leading, by a combination of features to a new object, or to new operating steps, or to new sequences of operating steps, provided that this also relates to manufacturing processes, control and

Implementation.

Claims (15)

  l.Vehicle comprising a device for automated actuation of a mechanism, such as for example a transmission and / or a torque transmission system, such as a clutch (3), in the drive train of this vehicle cooperating with at least one control unit, ensuring the control of the automated actuation of the clutch (3) and which is in relation to signal transmission with at least one electronic system (100) for anti-slip regulation, which produces a control signal when it is active in a skating situation, as well as with at least one operating member which can be controlled by the control unit for regulating the torque which can be transmitted by the clutch (3), vehicle characterized in that , in the case of an automated actuation of the clutch (3) and during the manifestation of a control signal from the anti-skid regulation system (100) indicating an activity thereof, the control unit ensures the order of the torque transmissible by the clutch (3) by means of the operating member for passing this transmissible torque from the value   currently set up to a maximum value.   2.Vehicle comprising a device for automated actuation of a clutch (3) located in the engine train of the vehicle, comprising a drive unit, a transmission and a clutch (3), such as for example a friction clutch, this device cooperating with a control unit ensuring the control of the automated actuation of the clutch (3) and which is in relation to the transmission of signals with sensors and if necessary with other electronic units, such as an electronic control system engine, an electronic ABS system and / or an electronic anti-skid control system (100), this electronic anti-skid control system (100) producing a control signal when it is active in a skid situation, as well as with an operating member which can be controlled by the control unit with a view to actuating the clutch (3), a vehicle characterized in that, during an automated actuation of the clutch (3) and when a signal from the anti-skid control system indicates that this anti-skid control system (100) is active, the control unit controls the clutch to move it from the current position   clutch to a full clutch position.   3. Vehicle according to one of claims 1 or 2,   characterized in that, apart from the automated actuation of the clutch (3), it is also possible to control an automated actuation of the transmission by means of an operating member (60) and a control unit ordering this operating device.   4. Vehicle according to one of claims 1 to 3,   characterized in that a command to increase the torque which can be transmitted by the clutch (3) by means of the control unit and the operating member, when a control signal is manifested ( 202) of the anti-skid system indicating an activity thereof, is carried out at a speed which is equal to or greater than the speed which can be obtained in the case of a control operation without the manifestation of a signal   control (202) of the traction control system.   5. Vehicle according to one of claims 1 to 4,   characterized in that a command to increase the torque which can be transmitted by the clutch, when a control signal (202) from the anti-skid control system (100) indicates the activity of the latter ci, is carried out at a speed which is equal to or greater than the speed which can be obtained in the case of a control operation without the manifestation of a   control signal from the anti regulation system   slippage, also when, without the manifestation of such a control signal, the transmissible torque or the clutch position of the clutch would not be practically unchanged.   6. Vehicle according to one of claims 1 to 5,   characterized in that a command for the increase in the torque which can be transmitted by the clutch, when a control signal (200) from the anti-skid control system (100) indicates the activity of the latter ci, is performed at a predetermined speed, which is equal to or greater than the speed which can be obtained during a control operation without the manifestation of a control signal from the anti-skid control system, also when, without the manifestation of such a control signal, the transmissible torque or the clutch position of the clutch in the current operating range would not be practically unchanged.   7.Vehicle according to one of claims 1 to 6,   characterized in that the control unit increases to a maximum the torque which can be transmitted by the clutch (3) during an activity of a traction control system (100) or produces a clutch of the clutch, at least as long as there is no control signal differing from this condition,   for example during a switching process.   8. Vehicle according to one of claims 1 to 7,   characterized in that, upon the manifestation of an activity of the anti-skid control system (100), the control unit (50) produces a control signal for a clutch of the clutch, only when the speed of motor rotation (nrnot) is greater than one predetermined value.   9. Vehicle according to one of claims 1 to 8,   characterized in that, upon the manifestation of an activity of the anti-skid regulation system (100), the control unit (50) produces a clutch control command signal for a rotation speed nmot of the engine which is higher than the idling speed plus a predetermined speed.   10. Vehicle according to one of claims 1 to 9,   characterized in that the control unit (50) produces a clutch control signal of the clutch (3) only in the case of a control signal produced   and / or transmitted by the anti-regulation system skating.   11. Vehicle according to one of claims 1 to 10,   characterized in that the control unit (50) produces a clutch clutch control signal only in the case of a control signal produced and / or transmitted by the traction control system and during the event of a rotation speed nmot of   motor which is greater than a predetermined value.   12. Vehicle according to one of claims 1 to 11,   characterized in that, after the manifestation of a control signal which indicates an activity of an anti-skid regulation system and / or upon the manifestation of a signal which indicates a stop of activity of the anti-skid regulation system - skating, unity. control (50) controls the torque that can be transmitted by the clutch (3) to change it to a suitable value at the current running position.   13.Vehicle according to claim 12, characterized in that the transmissible torque, controlled to a value adapted to the driving position, takes a value falling within a range between a minimum value and a maximum value.   14. Vehicle according to claim 13, characterized in that the minimum value is substantially zero and the maximum value is the value which can be adjusted to the maximum. 15. Method for controlling a torque which can be transmitted by a clutch of a vehicle by means of a device for automated actuation of the clutch (3), operating in combination with a control unit ensuring the control of the automated actuation of the clutch (3) and which is in relation to signal transmission with an anti-skid control system (100), which produces a control signal when it is active in a skating situation, as well as with an operating member, which can be controlled by the control unit for regulating the torque which can be transmitted by the clutch (3) and controlled by the control unit, method characterized in that, upon actuation automated clutch, the control unit performs the following operations: - an analysis operation to determine the existence of a control signal indicating an activity of the anti-skid regulation system (100), - during the demonstration of this signal, an operation for controlling the torque which can be transmitted by the clutch (3) by means of the operating member to cause it to pass from the value currently set up to a   maximum value of this transmissible torque.