FR2785238A1 - Controlling motor vehicle with automatic gearbox involves limiting engine torque to limiting value below predefined torque when driving with slipping clutch, pref. in first gear - Google Patents

Abstract

The method involves limiting the engine torque (2) to a first limiting value (4) below a predefined torque when driving with a slipping clutch, pref. in first gear. The torque limiting can be applied in a starting gear, pref. first, second or reverse gear. When driving with slip has finished the torque is limited to a second value above the first limit value but below the predefined torque. Other torque limit values can be used, e.g. for fuel saving mode. Independent claims are also included for an arrangement for controlling a motor vehicle with an automatic gearbox and for a vehicle with such an arrangement.

Description

 The invention relates to a method for controlling a vehicle equipped with a gear change, in particular an automated gearbox. It also relates to a device, in particular for the implementation of this method, for controlling a vehicle equipped with an automated gearbox, as well as a vehicle provided with such a device.

 Motor vehicles that are currently known, frequently have a gearbox to be controlled manually by the driver of the vehicle and having several ratios or speeds. Automatic gearboxes with stage ratios are also known, but which have the drawback of being much more expensive than the aforementioned manual control boxes.

 An automatic transmission has the advantage that comfort is increased, but this advantage is obtained at the cost of a more expensive construction, which is the origin of the mentioned disadvantage of the higher cost. For these reasons, the proportion of vehicles with relatively low engine power and having automatic transmissions is very small; in many cases, small cars are not even offered with an automatic transmission. As the density of traffic is constantly increasing, traffic situations change constantly and require different traffic speeds, therefore frequent speed changes.

 In order to provide the user of a motor vehicle not equipped with an automatic transmission also with greater driving comfort, various attempts to automate gearboxes are also already known. In this case, we start from a manual gearbox and the result is fundamentally different from an automatic gearbox with stages in that the gear changes in the latter can be carried out without interruption of the traction or propulsion force. of the vehicle, while the automatic transmission involves an interruption of the transmission of forces from the engine through the clutch to the gearbox.

 In the case of a motor vehicle equipped with an internal combustion engine, there is a large excess of engine power at low speed. A manual gearbox coupled to such an engine, has a gear staging whose deviations become smaller as the gears increase, so that especially to go from first to second gear, there is a large difference between reports, compared to differences between the following reports.

 However, in order to minimize the means to be used for construction, as well as the costs associated therewith, it should be possible to use, to automate gearboxes, gearboxes as much as possible unchanged and having the above-mentioned progressive layering of reports.

 Based on this situation, the invention aims to create a method and a device for controlling a vehicle equipped with an automated gearbox, so that a vehicle thus controlled has great comfort in changing gears and driving. for the driver and passengers.

 Several solutions and modes of implementation will be described below to obtain this result by the method according to the invention. Different embodiments of the device according to the invention will also be described below.

 The invention starts from the observation that motor vehicles powered by an internal combustion engine are not driven, for far most of their operating time, with the maximum possible engine torque, but that the user d 'Such a vehicle generally requires, in normal use, only part of this maximum torque. The torque request is made in most cases by a more or less deep depressing of the accelerator pedal. However, the engine torque which can be predetermined in this way, can also be prefixed by an electronic control device.

 The invention therefore provides a method of controlling a vehicle equipped with an automated gearbox, the vehicle having a motor that can be coupled via a controlled clutch (piloted) to the gearbox, according to which , during a walk with a clutch slipping, in particular during a departure, the engine torque is limited to a first limitation value less than a engine torque which can be predetermined. This means that the user of such a vehicle requests a predetermined torque by the position of the accelerator pedal. The departure is carried out, as is usual, with a clutch which slips, while the speed of rotation of the engine remains substantially constant.

If the method according to the invention is applied, the engine torque actually delivered by the engine during this departure is limited to a first limitation value which is less than the predetermined engine torque. A characteristic of the method according to the invention provides that the engine torque is limited, during a walk with a slipping clutch, while, preferably, a starting gear, such as first speed, second speed or reverse is engaged in the box.

 By this limitation of the torque to a first limitation value below the predetermined engine torque, it is obtained that the departure, with a slipping clutch, takes place uniformly, without starting jerks, detrimental to comfort, since it takes place with a torque limited to said first value.

 When the slippery use of the clutch is almost completely finished, so when the clutch is at least engaged almost to the point that there is no more slippage, but adhesion of the cooperating surfaces of the 'clutch, the invention provides for the limitation of the engine torque to a second limitation value greater than the first limitation value and less than the predetermined engine torque. During departure with a slipping clutch, the engine speed remains substantially constant. The torque produced by the engine, however, ensures, in this situation, a strong acceleration of the vehicle.

After the end of the starting phase with a slipping clutch, the continuation of the advance of the vehicle while the starting gear remains engaged, therefore generally in first, would certainly bring an additional acceleration of the vehicle, but it would occur, due to the increase in engine speed taking place at this time, a transition from strong acceleration to weaker acceleration of the vehicle. By the adjustment provided according to the invention of the engine torque, following practically the end of the slippery state of the clutch, to a second limitation value, greater than the first, the decrease in the acceleration of the motor vehicle , which degrades comfort, is avoided.

 A development of the method according to the invention provides that when the second speed is engaged, the engine torque is adjusted to a third limitation value less than the predetermined engine torque and greater than the first limitation value. The term "second speed" here designates the speed or the gear following the gear usually used for departures from a stop or a very low speed of the vehicle.

 The second is a speed frequently used for restarts, that is to say to re-accelerate while the vehicle equipped with the automatic gearbox has not yet stopped completely in a situation where a downshift from the second to the first, scheduled for departure, is not necessary or is undesirable for comfort. Therefore, for the second gear, the engine torque is limited to a third limitation vater lower than the predetermined engine torque which is requested at the time considered, but greater than the first limitation value set for departure with the slip clutch. It is thus obtained that the vehicle can be restarted quickly and with little load on the clutch.

 Another development of the method according to the invention provides that at least one of the limitation values is adjusted as a function of a predetermined operating mode. The latter can be preselected by the user of the motor vehicle, who can choose, for example, from a plurality of operating modes including a so-called economical mode for saving fuel, a sporty driving program, a driving program with change of automatic speed, a manual shift program or the like.

 If the user of the motor vehicle equipped with the automated gearbox, for example, chooses an operating mode designed to save fuel for the engine, the engine torque limitation value will be adjusted, in accordance with the process, to a level lower than a limitation value - possibly existing - which is set when the user, as a result of his mode selection, requests the provision of higher engine torques for greater acceleration of the vehicle, for example because it is decided for a sport driving program.

Therefore, in an operating mode designed to save engine fuel, the limitation value is set lower than for another predetermined operating mode.

 If, for example, the user chooses a driving program controlling the automated gearbox so that the different gear ratios are passed without the user having to intervene, it is possible to set the limitation value to a lower level only if a manual operating mode of the gearbox is selected, for which the user has an influence on changing the gear ratios of the gearbox.

 The method according to the invention also provides that at least one of the limitation values is increased in the event of a limit value of the predetermined motor torque being exceeded. The latter can be very fixed by actuation of the accelerator pedal. The acceleration, speed, engine power or engine torque desired by the driver can thus be controlled. Exceeding the predetermined limit value of the engine torque can be produced, for example, by rapid actuation of the accelerator pedal by the user, which can be observed by determining a gradient, or by maneuvering '' a switch on the accelerator pedal ("kick-down"). When the user of the vehicle equipped with the automated transmission manifests the desire for a strong acceleration of the vehicle by such actuation of the accelerator, the increase in the limitation value, thus produced, ensures that the user has, for the acceleration of the vehicle, all or substantially all of the engine torque, in accordance with his request.

 The invention also provides a device for controlling a vehicle equipped with an automated gearbox, in particular for implementing the method according to the invention. Such a device can be provided on a vehicle having a motor which can be coupled via a clutch controlled (piloted) to the gearbox and it comprises a piloting device which, during a march with a clutch which slips, in particular during a start, limits the engine torque to a first limitation value less than a predetermined engine torque. This allows a smooth, uniform and jerk-free departure of the vehicle while the engine rotation speed remains substantially the same.

 When the use of the clutch in the slipping state is practically finished, the control device limits the engine torque to a second limitation value greater than the first limitation value and less than the predetermined engine torque. It is thus obtained that the transition from a departure with slipping clutch and constant speed of the engine to a march without slippage and at increasing speed of the engine, is not accompanied by a transition from a strong acceleration to a weaker acceleration of the vehicle. By limiting the engine torque to a second value, which is higher than the first, it is obtained that the acceleration of the vehicle does not change appreciably when passing from the slip state of the clutch to the fully engaged state.

 A development of the invention provides that the control device governs the engine torque at second speed at a third limitation value less than the predetermined engine torque, and provides a higher engine torque than that corresponding to the first limitation. This third limitation is used mainly for restarts of the vehicle, equipped with an automated gearbox, during which the clutch remains in the fully engaged state and this third higher limitation allows a rapid restart of the vehicle without requesting the clutch by a skating.

 The control device may have an adjustment element, to be actuated by the user of the vehicle, by which he can preselect the desired operating mode. A characteristic of the invention provides that the control device adjusts at least one of the limitation values as a function of a predetermined operating mode. If the user wishes for example an operating mode designed to save fuel, the control device adjusts at least one of the limitations according to this preselected mode. In a mode or in the operating mode designed to save engine fuel, the control device sets the limitation value at a lower level than for another predetermined operating mode, or the limitation values are set at a higher level. lower than in the case of an operating mode intended for strong acceleration of the vehicle. The user also has the option of choosing an automatic mode, so that the steering device then controls the automated gearbox so that the actuators provided shift the gearbox to higher gears while the engine is still running at low speed and operate for this purpose the clutch accordingly. According to another embodiment, the control device can also allow an adaptive control of the gearbox, so that an adjustment of the limitation values is also possible in the automatic speed change mode, in accordance with a recognition of user.

 Other features provide that the control device increases at least one of the limitations in the event of a limit value of the predetermined engine torque being exceeded and that the engine torque is preferably predetermined using the accelerator pedal. .

 On the accelerator pedal of the vehicle equipped with an automated gearbox, a switch can be provided which, after its actuation, increases at least one of the limitations, so that the user of the vehicle has, for the acceleration of the vehicle, of an engine torque corresponding to the engine torque requested by it through the position of the accelerator pedal or the speed of actuation of this pedal.

 The method and the device according to the invention provide great comfort to a vehicle equipped with an automated gearbox since the engine torque is adjusted each time according to the necessary torque. In fact, if the user wishes a regular acceleration of the vehicle, which he manifests by not asking for the maximum possible engine torque, the vehicle is accelerated in a substantially constant manner, in accordance with the shifting of ratios, due to the increases. of the torque limitation. Thanks to the increase in engine torque at the third limitation after switching from the first to the second, a uniform transition is obtained - increasing comfort - despite the large gap between the gear ratios concerned from the transition from the first to the second. It is clear from the above that the driver of the vehicle equipped with an automated gearbox and a device according to the invention has the possibility of influencing the limitations, therefore also the driving dynamics of the vehicle.

 The invention further provides a vehicle equipped with an automated gearbox, comprising a motor which can be coupled by a clutch controlled to the gearbox, which is characterized in that it is provided with a device according to the invention as the one just described.

Still other characteristics and advantages of the invention will emerge more clearly from the description which follows, given with reference to the Figures of the drawings, in which:
FIG. 1 is a diagram schematically illustrating a process for starting a vehicle with speed change in accordance with the control method according to the invention;
FIG. 2 schematically represents a vehicle in which the invention can be implemented; and
FIG. 3 schematically represents another vehicle in which the invention can be implemented.

 Figure 1 shows in its upper half the actuation of the accelerator pedal, designated by the reference 1. As can be seen from this diagram, the driver actuates the vehicle accelerator, equipped with an automated gearbox , at time to. The accelerator is then kept in the same position for the entire duration covered by the diagram in FIG. 1.

 Following actuation of the accelerator, the motor torque 2 increases, as shown by the curve in solid lines. The reference 2a designates a part of the curve in broken lines representing the engine torque being established, according to the position of the accelerator, without the control according to the invention. It is clearly seen that the engine torque (2a) would rise in this case, in accordance with the actuation 1 of the accelerator and with delay relative to it, and then remains about the same, in accordance with the position constant of the accelerator pedal.

 In the case of the operating mode chosen by the user of the vehicle, to which the diagram in FIG. 1 relates and which is designed to save fuel, the control device according to the invention ensures that the engine torque is limited to contrary, during the departure of the vehicle, to a first limitation value 4.

 This first limitation 4 is below the possible value 2a of the engine torque in accordance with the position of the accelerator, and is maintained in force while the clutch is in a slippery state for the departure of the vehicle. During this start of the departure of the vehicle with a slipping clutch, the speed of rotation 3 of the engine remains substantially the same and the speed of rotation 5 at the outlet of the gearbox increases.

 At time tl, the starting phase with the clutch slipping is almost complete - the vehicle continues to be advanced first - and the control device according to the invention controls the engine so that the engine torque delivered is increased to the second limitation value 6.

This second limitation is less than the engine torque 2a corresponding to the position of the accelerator, but greater than the first limitation 4.

 As can be seen from the almost linear increase in the speed of rotation 5 at the outlet of the gearbox as a function of the time between the instants ti and t2 of the diagram in FIG. 1, this second limitation, to a torque value more high, has the consequence that the vehicle continues to be accelerated with an acceleration remaining almost the same.

 At time t2, the transition from the first to the second speed is also triggered, which emerges from the slightly descending curve of the speed of rotation 5 at the exit of the gearbox. During a gear change on a vehicle fitted with an automated gearbox, the engine torque can also, briefly, be reduced even more, to values below limitation 6. When the gear change is complete, at instant t3, after which the second is therefore engaged in the automated gearbox, the control device according to the invention increases the usable engine torque to a third limitation value 7, which is greater than the first two limitations 4,5, while remaining below the value of the possible engine torque-following the curve part 2a-according to the actuation 1 of the accelerator pedal.

 The increase in the engine torque which can be used in the third limitation 7 has the effect that the vehicle, equipped with the automated gearbox and the device according to the invention, can start or restart, also in second, quickly and without stresses on the clutch.

 The staggered limitation of the engine torque, provided according to this example of implementation, also has the effect that the driver is less aware of the interruption of the traction or propulsion force of the vehicle during the gear change operation. , so that the comfort of changing gear and driving the vehicle, equipped for example with a clutch controlled by an electric motor, as well as the automated gearbox, is markedly increased.

 The invention therefore provides a method and a device for controlling a vehicle equipped with an automated gearbox, by which the engine torque is limited to a first value, less than an engine torque which can be predetermined, during a departure of the vehicle with a slip clutch. After the end of the use of the clutch in the slip state, the engine torque is limited to a second value greater than the first and less than the predetermined engine torque. Then, after a gear change, the engine torque is allowed to rise to a third limitation greater than the first and the second limitation.

 Figure 2 shows a vehicle 201 provided with engine equipment 202, for example in the form of an internal combustion engine or of a hybrid system having an internal combustion engine and an electric motor, of a transmission system of torque 203, for example in the form of a clutch, and of a gearbox 204, which is followed by a transmission shaft 205 which, by means of a differential 206, drives two wheel shafts 207a and 207b themselves controlling the driving wheels 208a and 208b. The torque transmission system 203 is constituted by a friction clutch comprising a flywheel 209, a thrust plate 210, a clutch disc 211, a clutch release bearing 212 and a clutch release fork 213. The latter is operated by means of a control device in the form of an actuator 215 having a transmitter cylinder 216, a pressure fluid line 217, such as a hydraulic line, and a receiving cylinder 218. The actuator 215 is shown as a device driven by a pressure fluid and comprising an electric motor 219 which, by means of a speed reducer, produces the displacement of a piston 220 of the emitting cylinder 216, so that, through the line to pressure fluid 217 and via the receiving cylinder 218, the torque transmission system can be engaged and disengaged. The actuator 215 further comprises the electronics for actuating and controlling the actuator, namely both the power electronics and the control or piloting electronics. The actuator is provided with an air renewal orifice 221 connected to a reservoir 222 for the pressure liquid.

 The vehicle 201, fitted with the gearbox 204, has a gearshift lever 230 to which are combined a sensor 231 detecting the speed engaged and a sensor 232 determining the speed which will be engaged by the driver according to the movement that this prints to the gearshift lever or according to the force exerted by it on this lever. The vehicle is further equipped with a sensor 233 for detecting the speed of rotation of the output shaft of the gearbox, the transmission shaft or the wheels. In addition, the vehicle includes a sensor 234 for detecting the position of the throttle valve and a sensor 235 for detecting the rotation speed of the engine.

 The engaged speed sensor 231 detects the position of internal gear changing elements of the gearbox or the speed engaged in the gearbox, so that, by the signal delivered by this sensor, the control unit records at least the speed engaged. In addition, if it is an analog sensor, the movement of the internal gear change elements of the gearbox can be detected, so that the gear engaged thereafter can be recognized early.

 The actuator 215 is powered by a battery 240. The vehicle also has an ignition switch 241, generally with several stages, which is operated as a general rule by the ignition key, which causes, through the line 242, starting the internal combustion engine starter 202. A signal is sent via line 243 to the electronic unit of the actuator 215 to activate the latter, for example when the ignition is switched on.

 Figure 2 also shows, schematically, in the form of a block 250, an anti-recoil latching device which cooperates with at least one brake 251 of the vehicle and actuates it at least from time to time in an automated manner. For this purpose, the block 250 also comprises an electronic control unit and the block 251 comprises an actuation unit.

The control unit 250 has a signal transmission link 252 with the automated clutch control unit.

 Figure 3 is a schematic representation of the kinematic chain of a motor vehicle equipped with an engine assembly 601, for example in the form of an internal combustion engine, of a torque transmission system 602, for example under the form of a friction clutch, of the dry operating type or of the wet type, of a gearbox 603, as well as of a differential 604, of wheel shafts 605 and of wheels 606 controlled by these shafts. Rotational speed sensors, not shown, can be installed on the wheels to detect their rotational speeds. These sensors can also functionally belong to other electronic units, such as for example an anti-lock system. The engine assembly 601 can also be produced in the form of a hybrid system comprising, for example, an electric motor, a flywheel with a freewheel, as well as an internal combustion engine.

 In the example shown here, the torque transmission system 602 is formed by a friction clutch, but it can also be constituted, for example, by a magnetic powder clutch, a multi-disc clutch or a torque converter provided with a converter cut-off or bypass clutch, or by a clutch or coupling of another type. In addition, FIG. 3 shows a control device in the form of a control unit 607 and an actuator 608, shown diagrammatically. The friction clutch can also be made as a clutch with automatic wear adjustment.

 The torque transmission system 602 is mounted on or connected to a flywheel 602a, which can be a divided flywheel comprising a primary mass and a secondary mass with a damping device between them, on which a toothed ring is arranged 602b attacked by the starter. In this example, the torque transmission system comprises a clutch disc 602c carrying friction linings, a thrust plate 602c, a clutch closing plate 602a and a diaphragm spring 602f. The clutch, of the automatic wear-take-up type, also includes means allowing adjustment and adjustment to compensate for wear, as well as a sensor, in the form of a force or distance sensor. for example, which detects a situation requiring an adjustment, which, if such detection takes place, can also be carried out.

 The torque transmission system is actuated by means of a declutching 609, such as for example a central declutching driven by a pressure fluid, such as a central hydraulic declutching. The clutch can carry a clutch release bearing 610 and is capable, if actuated accordingly, of producing engagement and opening of the clutch. The declutching can however also be of the mechanical type and actuate, act on or maneuver a declutching stop or a comparable element.

 The actuator 608, constituting for example an actuation, control unit, by means of a mechanical connection or through a pressure fluid line 611 or a transmission circuit such as a hydraulic line, the mechanical clutch or hydraulic or central disengage 609 for engagement and disengagement of) 'clutch. By its output element or by its output elements, the actuator 608 also drives the gearbox, the element or elements of the actuator output acting for example on a central gear shift shaft or primary shaft of the box.

The actuator 608 therefore acts on internal elements of the gearbox for re-engagement,) the release or the change of gears or speeds, the elements being constituted for example by a central or primary shaft, speed change rods or other shifting elements.

 The actuator 608 can also be made or provided as an actuator with a speed change cylinder placed inside the box. Such a cylinder actuates, under the effect of its own rotation which has been printed on it, elements circulating in guides and constituting speed change elements for example, to change the different speeds. In addition, the actuator for shifting gears may also contain the actuator intended to actuate the torque transmission system, in which case a functional connection with the clutch disengaging is necessary.

 The control unit 607 is connected by the signal transmission link 612 to the actuator 608, so that control signals and / or sensor signals or signals representative of operating states can be exchanged, transmitted or questioned. The system also has signal transmission links 613 and 614 by which the control unit can be in signal transmission link, at least temporarily, with other sensors or electronic units. With regard to such other electronic units, this may for example be engine electronics, electronics of an anti-lock system or electronic traction control.

Other sensors can be constituted by sensors which characterize or generally detect the operating state of the vehicle, such as for example sensors for detecting the speed of rotation of the engine or wheels, sensors for determining the position of the throttle or the accelerator pedal or other sensors. The signal transmission link 615 establishes a link with a data bus, such as for example a CAN bus, through which data from vehicle systems can be made available to the aforementioned electronic units or to other electronic units since those - these are generally interconnected in a network by computer units.

 A speed change in an automated gearbox can be triggered by the driver of the vehicle, for example because by means of a switch, he delivers a signal to shift to a higher speed or to downshift. In addition, a signal indicating what speed should be engaged in the gearbox, can also be provided by means of an electronic lever. However, an automated gearbox can also change gear independently, for example using characteristic values, curves or diagrams and on the basis of sensor signals at certain predetermined points, without the driver having to initiate a change of speed.

 The vehicle is preferably equipped with an electronic accelerator pedal 623 or an electronic load lever. The accelerator 623 acts on a sensor 624 using which the engine electronics 620 controls or regulates, for example, by the signal line 621 of the engine 601, the fuel supply, the ignition time, the time ignition position or throttle position. The electronic accelerator 623 and the sensor 624 are in signal transmission link with the engine electronics 620 by the line 625. By the line 622, the engine electronics 620 is in addition in signal transmission link with the unit 607 control electronics. In addition, a 630 gearbox control electronics can be in signal transmission link with the 607 and 620 units. It is advisable to provide for this purpose an electric motor control of the throttle valve, the position of this ci being pi lot by the engine electronics. A direct mechanical connection with the accelerator pedal is no longer necessary or useful in such systems.

 The claims filed with the application are proposals for wording without prejudice to obtaining protection going further.

The plaintiff reserves the right to claim yet other characteristics, so far disclosed only in the description and / or the drawings.

 Attachments used in the dependent claims indicate the development of the subject matter of the main claim by the features of the dependent claim concerned; they should not be understood as a renouncement of obtaining independent device protection for the characteristics of the dependent claims attached thereto.

 The objects of these dependent claims, however, also constitute autonomous inventions, having a configuration independent of the objects of the preceding sub-claims.

 The invention is also not limited to the example or the exemplary embodiments given in the description. Many changes and numerous modifications are on the contrary possible within the scope of the invention; these are in particular variants, elements and combinations and / or materials which have an inventive level, for example by combination or modification of characteristics, elements or individual process steps, described in conjunction with the general description and the embodiments as well as the claims and contained in the drawings and which can lead, by characteristics capable of being combined, to a new object or to new steps or sequences of process and working steps.

Claims (19)

 1. Method for controlling a vehicle equipped with an automated gearbox, comprising a motor (202; 601) which can be coupled by a clutch (203; 602) to the gearbox, characterized in that one limits the engine torque at a first limitation value (4), less than a engine torque which can be predetermined, during a walk with a clutch (203; 602) slipping.  2. Method according to claim 1, characterized in that the engine torque is limited, while walking with a clutch (203; 602) slipping, while, preferably, the first gear of the gearbox; 603) is engaged.  3. Method according to claim 1, characterized in that the engine torque is limited, during a walk with a clutch (203; 602) slipping, while, preferably, a starting gear, such as the first speed, the second gear or reverse gear is engaged in the gearbox (204; 603).  4. Method according to one of the preceding claims, characterized in that, when the use of the clutch (203; 602) in the slip state is practically finished, the engine torque is limited to a second limitation value ( 6) greater than the first limitation value (4) and less than the predetermined motor torque.  5. Method according to one of the preceding claims, characterized in that, when the second speed is engaged in the box (204; 603), the engine torque is limited to a third limitation value (7) lower than the predetermined engine torque .  6. Method according to claim 5, characterized in that the third limitation value (7) is adjusted above the first limitation value (4).  7. Method according to one of the preceding claims, characterized in that at least one of the limitation values (4,6,7) is adjusted as a function of the predetermined operating modes.  8. Method according to one of the preceding claims, characterized in that, in an operating mode designed to save the engine fuel, the limitation value (4,6,7) is governed at a lower level than for a other predetermined operating mode.  9. Method according to one of the preceding claims, characterized in that, if a limit value of the predetermined motor torque is exceeded, at least one of the limitation values (4,6,7) is increased.  10. Method according to one of the preceding claims, characterized in that the engine torque is predetermined preferably with the aid of the accelerator pedal (623) of the vehicle.  11. Control device for a vehicle equipped with an automated gearbox (204; 603), comprising a motor (202; 601) which can be coupled by a controlled (controlled) clutch (203; 602) to the gearbox ( 204; 603), in particular for implementing the method according to one of claims 1 to 10, characterized by a control device (215; 607) which, during a walk with a clutch (203; 602) which slips, limits the engine torque to a first limitation value (4) lower than a engine torque which can be predetermined.  12. Device according to claim 11, characterized in that, when the use of the clutch (203; 602) in the slipping state is practically finished, the control device (215; 607) limits the engine torque to one second limitation value (6) greater than the first limitation value (4) and less than the predetermined motor torque.  13. Device according to claim 11 or 12, characterized in that, when the second gear is engaged in the box (204; 603), the control device (215; 607) adjusts the engine torque to a third lower limit value to the predetermined engine torque.  14. Device according to one of claims lia 13, characterized in that the control device (215; 607) sets the third limitation value (7) above the first limitation value (4).  15. Device according to one of claims 11 to 14, characterized in that the control device (215; 607) sets at least one of the limitation values (4,6,7) according to a predetermined operating mode .  16. Device according to claim 15, characterized in that, in an operating mode designed to save engine fuel (202; 601), the control device (215; 607) sets the limitation value to a level lower than for another predetermined operating mode.  17. Device according to one of claims 11 to 16, characterized in that, if a limit value of the predetermined motor torque is exceeded, the control device (215; 607) increases at least one of the limitation values.  18. Device according to one of claims lia 17, characterized in that the engine torque is preferably predeterminable using the accelerator pedal (623).  19. Vehicle equipped with an automated gearbox (204; 603), comprising a motor (202; 601) which can be coupled by a controlled (controlled) clutch (203; 603) to the gearbox (204; 603), characterized in that it is provided with a device according to one of claims 11 to 18.