FR2832476A1 - Method of starting motor vehicle movement involves controlling drive group output to medium speed range on stopping and summing torque from two clutches on starting off - Google Patents

Abstract

The method of starting a motor vehicle involves controlling the drive group output to a medium speed range when the vehicle is stopped, followed by actuating two clutches. The clutches provide a sum torque in an upper region of the maximum possible speed level. The increased engine speed provides increased acceleration on start up. Claims include a control system using the method.

Description

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Field of the invention
The present invention relates to a method of starting a motor vehicle comprising a transmission line equipped with a drive unit, a gearbox having at least two gearbox input shafts and an installation for double or multiple clutch for transmitting the torque between the drive unit and the gearbox, the clutch installation having a first clutch device associated with a first gearbox input shaft and a second device clutch associated with a second gearbox input shaft, which can be actuated selectively and independently in the clutch direction and / or in the clutch direction to induce a drive torque of the unit d drive in the gearbox, selectively via the first input shaft and / or the second input shaft of the gearbox, the drive torque of which is transmitted s as a function of an instantaneous gear ratio state of the gearbox on at least one gearbox output shaft, if necessary after conversion of the torque in a corresponding manner according to an instant gear reduction ratio of one gear ratio passed with respect to the respective input shaft of the gearbox, and the torque of the output shaft of the gearbox is transmitted to the drive wheels of the vehicle, process in which during a start-up phase by the first and the second clutch device at least one of the two operates with slip and the two clutch devices transmit simultaneously as a function of an instantaneous torque transmission capacity of the clutch devices, the drive torque to the first and second gearbox input shafts, by adjusting for the two gearbox input shafts each time a gear ratio, to transmit the e drive torque transmitted to the respective gearbox input shaft correspondingly to the respective gearbox ratio up to the gearbox output shaft so that the output shaft of gearbox receives a corresponding total drive torque for driving the drive wheels.

 Such a process is known for example according to document DE 38 12 327 C2. The description of the figures in this document shows in connection with FIG. 9 that the rotational speed / time curves represented in this figure (linear increase in the rotational speed of the input shafts of the gearboxes) are based on the assumption that the

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engine speed remains constant. It is not clear whether this is a hypothesis intended to simplify the representation of rotation speeds or an example of starting. Other indications concerning the nature and the manner of starting are not given.
Starting using two clutches integrated into a gearbox is also known according to document DE 199 11 027 Al.

In addition, reference will be made to document DE 35 46 454 C2 which describes two clutch devices of a double clutch which are only connected in parallel to transmit the torque transmitted in common by these two clutches by the speed ratio used, c '' ie by the input shaft of the gearbox associated with this gear ratio, to transmit the torque to the gearbox and then to the drive wheels.

 The document DE 196 53 855 C1 describes a method of starting a vehicle as well as a control installation for the implementation of this starting process called sports starting (racing starting). It is proposed to intentionally create slippage at the level of the driving wheels of the vehicle and to regulate this slippage by means of a friction clutch in the form of a simple clutch. To prepare for starting, at the start of the starting phase, the friction clutch still being open or the vehicle stationary, the engine is controlled to increase its speed beyond the predetermined threshold of the engine speed.

Statement of the invention
The present invention relates to a method of the type defined above allowing a particularly efficient starting, preferably a so-called sport or racing starting of the vehicle, according to which advantage is used of all the possibilities offered by a double or multiple clutch installation for on the one hand to arrive at a significant acceleration of the vehicle and on the other hand to maintain the load of the clutch installation or the clutch devices within a determined framework.

 To this end, the invention relates to a method of the type defined above, characterized in that i) first of all the vehicle being still, the speed of rotation (nM) of the drive unit is driven to a output rotational speed level which lies in a medium zone, preferably in an upper zone, of a rotational speed interval defined by a minimum rotational speed or idle rotational speed and

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 a maximum rotation speed authorized in the drive unit, and ii) then the drive unit and the first and second clutch devices are operated in common by engaging them until - d ' on the one hand the drive unit provides a drive torque (MM) which is at least in an upper region of a drive torque interval defined by the zero drive torque and a maximum drive torque possible for the speed level, and - on the other hand the first clutch device transmits a first torque (Mi) and the second clutch device a second torque (M2) to the respective input shaft of the gearbox, the sum (Mk) of the torques also corresponding at least to a higher range of the drive torque interval defined by the zero drive torque and the maximum possible drive torque for the level of the speed of rotation.

 Characteristic i) is based on the consideration that it is advantageous, for particularly intense or optimal acceleration of the vehicle, to increase the speed of rotation of the drive unit, generally an internal combustion engine or turbine, at the start of the start-up phase at as high a rotation speed (speed) level as possible, the maximum rotation speed of the drive (motor) being defined beforehand by the stress limits of the clutch system. Thus, according to characteristic ii) a large drive torque can be called up by the drive unit so that, especially depending on the possibility of transmission of the drive torque by the drive wheels to the road, it is possible to actually get the desired acceleration for the vehicle. It is possible to have slippage between the driving wheels and the road or to avoid it or at least limit it, for example by an anti-skid regulation which by action in the management of the drive unit (engine management) reduces correspondingly the engine torque (drive torque), or by controlling or regulating the overall torque transmitted by the clutch devices and collected at the output of the gearbox as corresponding total engine torque. In the latter possibility, a command or a regulation of the first and / or the second pair can be provided.

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 Preferably, before the first clutch of the first and second clutch device in common, at least one of the two clutch devices is engaged, beforehand and sufficiently so that the clutch device concerned transmits a torque. significantly lower than the first and second torque but slightly exceeding the drag torque produced. This makes it possible to avoid idle times related to the air gap or similar causes in the clutch devices so that substantially in response to a start signal, the acceleration operation can be carried out without any delay embarrassing.

 According to a particularly advantageous development of the method, the sum of the first and the second torque is greater than the drive torque supplied by the drive unit according to the level of rotational speed provided that the rotational speed of the drive remains essentially constant, so that the speed of rotation of the drive as a result of the clutching of the two clutch devices decreases. According to another development, the rotational energy accumulated in the drive unit including in the input side of the clutch installation is used during a first phase of the starting operation proper , to provide total drive torque, increased at the gearbox output shaft.

This thus makes it possible to obtain a greater total drive torque than would be possible in the situation of a drive rotation speed remaining essentially constant. This applies in all cases if the sum of the first and second torque is greater than the maximum possible drive torque regardless of the level of the rotational speed. In the case of internal combustion engines, in the upper range of the speed range, the maximum drive torque provided by the engine when accelerating is only slightly increased so that by storing the rotational energy before starting proper, a significant increase in the engine torque transmissible to the driving wheels is actually achieved, and this increase has at least the psychological effect for the driver concerned insofar as the driver perceives the starting as a real sporting starting or race start.

 According to one development, it is proposed that if the drive rotation speed approaches a threshold rotation speed level situated below the output rotation speed level or reaches this level, on the two clutch devices, disengage the second and we

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 continues to engage the first gear or is kept in the engaged gear instantaneously so that the drive speed does not drop below the threshold speed level or at least does not drop significantly below of this level. After the consumption of the rotational energy thus accumulated, the acceleration is continued with the motor torque actually supplied by the drive unit. When in the first clutch device, the lowest speed ratio is used, then because of the reduction corresponding to this speed ratio in the gearbox, the drive torque collected on the output shaft of the gearbox is maximum. There will be almost a usual starting ensured only by a clutch (here only one clutch device).

 The first couple can be greater than the second couple.

This is particularly interesting if the first clutch device corresponds to the lowest gear ratio passed in the gearbox.

 According to an alternative embodiment of the method of the invention, the first torque is less than the drive torque that the drive unit can provide at the speed level with the condition of a speed remaining essentially constant. In this context but also independently of it, it is particularly advantageous that the total drive torque collected on the output shaft of the gearbox, supplied from the first and second torque is substantially equal to the torque of drive supplied to the gearbox output shaft as torque transmitted by the first clutch device to the gearbox input shaft after disengaging the second clutch device and continued clutch movement of the first clutch device.

 According to another alternative embodiment of the method of the invention, the first torque is substantially equal to the drive torque supplied by the drive unit for the level of speed of rotation assuming a speed of rotation essentially constant. In this context, but also independently of this, it is advantageously provided that the total drive torque collected on the output shaft of the gearbox corresponding to the first and second torque is greater than the drive torque collected on the gearbox output shaft due to the torque transmitted by the first

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 clutch device at the first input shaft of the gearbox after disengaging the second clutch device.

 As already indicated, the process can be carried out so that if the speed of rotation of the first input shaft of the gearbox reaches the level of the threshold of the speed of rotation, this speed of rotation continues to increase in common with the speed of rotation of the drive unit.

 According to an advantageous development of the method of the invention, the two clutch devices are multi-stage, preferably two-stage, and they are clutched to transmit the first and the second torque and the multi-stage clutch is made to that the vibration excitations of the transmission line partially compensate for each other. This makes it possible to avoid load change oscillations in the transmission line or at least to reduce these oscillations.

 The method can be carried out under the control and / or regulation of a vehicle or transmission line control installation. Thus, it is further proposed that the execution of the starting process is triggered in that first of all a vehicle movement signal transmitter, if necessary from the accelerator pedal, is actuated more strongly to exceed a threshold in the direction of activation or ramp-up of the drive unit and at the same time a vehicle brake signal transmitter, i.e. the brake pedal, is actuated more strongly that a minimum value in the direction of activation of the vehicle brake system and that thereafter, the actuation being maintained for the displacement signal transmitter, the brake signal transmitter is actuated in the direction of '' essentially total deactivation of the brake system.

 In this context, it is advantageous that the actuation of the brake signal transmitter is actuated more strongly than the threshold in the direction of activation or ramping up of the drive unit at the same time as the actuation of the brake signal transmitter is actuated more strongly than the minimum value in the direction of activation of the brake system, and that the speed of rotation of the drive reaches the level of the speed of output, that if necessary the clutch of at least one of the two clutch devices is triggered beforehand and that the actuation of the brake signal transmitter in the direction of an essentially total deactivation of the

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 brake, triggers the clutch of the first and second clutch device to transmit the first and second torque.

 According to document DE 196 53 855 Cl, it is already known to signal a sport start (race start) by a corresponding start switch; this switch is a switch which comes in addition to the other usual operating elements. However, it is not obvious that the need to actuate an additional operating component is accepted by drivers interested in starting a race. This is why the invention proposes that first of all the vehicle movement signal transmitter such that the accelerator pedal be depressed beyond a threshold value in the direction of activation or increase in speed of the drive unit and at the same time a vehicle brake signal transmitter such that the brake pedal is actuated more strongly than a minimum value in the direction of activation of the brake system of the vehicle and then, the actuation being maintained for the displacement signal transmitter, the brake signal transmitter wishes to actuate in the direction essentially of the total deactivation of the brake system, that is to say the brake pedal is released to signal the start request and trigger the start following this request. According to the invention, to signal the start request and initiate the corresponding start operation, it is expected that the driver performs maneuvers and actuations which are perceived as natural sequences for the corresponding start operations, and which are then necessary for a sporty start or intervene if on the basis of a purely manual actuation, the friction clutch of the motor vehicle must be started in this way.

 It is assumed that in connection with the invention, at least the clutch installation is actuated in a fully automatic manner and that the driver does not have a clutch pedal or the like. Preferably, the gearbox is also actuated automatically.

 The present invention further relates to a control installation for a motor vehicle. This installation is designed so that by an appropriate control of a drive unit and / or a gearbox and / or a clutch installation serving for the transmission of the torque between the drive unit and the gearbox and / or in a brake system as well as where appropriate other components

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 health or functionalities of the vehicle, it is recognized where appropriate as a sport start, a vehicle start operation to be performed and / or a corresponding request from the driver.

 According to the invention, it is planned to design the control installation so that the start-up operation is executed as described above and / or that the start-up request according to the method of the invention is recognized as described above. above and that thereafter the corresponding starting operation is triggered according to the method of the invention. The invention also relates to a vehicle equipped with such a control installation.

drawings
The present invention will be described below in more detail with the aid of an example embodiment shown in the accompanying drawings in which: - Figure 1 schematically shows a transmission line of a motor vehicle equipped with a double plate clutch and a load-switching gearbox operating according to the method of the invention and a control unit carrying out the method of the invention, - Figure 2 schematically shows a variant of the transmission line of FIG. 1 according to which the double wet lamella clutch is replaced by a dry double clutch, with friction discs, - FIG. 3 shows diagrams used to describe an exemplary embodiment of a method according to the invention for executing a race start, FIG. 4 shows diagrams used to describe a variant of the method of FIG. 3.

Description of embodiments
Figure 1 shows the example of a transmission line 1 of a motor vehicle.

 The transmission line comprises a drive unit 12 in the form of a combustion engine, in particular an internal combustion engine as schematically indicated by the crankshaft 14.

A load switching gearbox 18 is connected by two gearbox input shafts 20,22 fitted coaxially, by means of a double clutch 24 or to the motor 12. The double clutch 24 has two devices clutch 26,28 one of which is connected

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 to the gearbox input shaft 20 and the other to the gearbox input shaft 22. The embodiment is a clutch device with wet lamellae, which are actuated hydraulically by means of a sensor cylinder (not shown) integrated each time in the double clutch. A corresponding hydraulic pump 30 is shown diagrammatically. The cooling oil circuit associated with the double clutch with its cooling oil pump and the other accessories are not shown.

 When the two clutch devices are actuated, the control valves 32, 34 are electrically controlled by a control unit 36. The control unit receives the input signals from the accelerator pedal 38, of a speed ratio selection and / or influence unit 39, a speed sensor 40 associated with the input shaft 20 of the gearbox, a speed sensor 42 associated with the input shaft 22 of the gearbox as well as a rotation speed sensor 44 associated with the output shaft of the engine (crankshaft 14). The control unit can also receive signals and measured values from other sensors and signal generators such as the vehicle speed sensor, a steering angle sensor, a vehicle 'brake actuation state (this is the brake pedal 46 shown in Figure 1) and other sensors and accessories.

 By comparing on the one hand the rotational speed supplied by the rotational speed sensor 44 and the rotational speed supplied by the rotational speed sensor 40 or 42 on the other hand, the control unit can determine the state of slipping of the clutch device 26 or of the clutch device 28. The control unit 36 controls a power adjustment member of the engine 22 to adjust the torque or the power supplied by the engine.

 Figure 1 shows a generator-starter 50 associated with the crankshaft comprising a stator associated with the engine 12 and a rotors associated with the input of the double clutch 24. The generator-starter associated with the crankshaft 50 is activated by the control unit 36 in particular for starting the engine 12.

 For the gearbox with double clutch or gearbox with load switching 18 it should be noted that it is preferably a gearbox fully synchronized by an appropriate synchronization installation 52. The installation of synchroni-

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 station 52 is not necessarily a central synchronization installation for the entire gearbox. The synchronization installation can also include usual synchronization means such as synchronization rings. The gearbox output shaft carries the reference 54. The gearbox is preferably controlled fully automatically by the control unit 36 by the actuating installation 56.

 FIG. 2 shows another example of a transmission line 10 of a motor vehicle. Only the modifications with respect to the transmission line of FIG. 1 will be described. Instead of the double clutch 24 with two wet plate clutch devices 26, 28, FIG. 2 shows a double clutch 24 with two dry clutch devices 26, 28 of the friction clutch type. The two friction disc clutch devices can for example be actuated by hydraulic sensor cylinders integrated in the double clutch, by means of a hydraulic control according to FIG. 2.

 In certain operating cases, for example when starting the vehicle, it is possible to seek to minimize the stress on the clutch. In the case of double clutch or multiple clutch, provision can be made for this to distribute the loss of power between at least two (or both) clutch devices of each clutch installation. This solution is used in particular to perform a sport start.

 Other designs can also be followed to avoid or reduce thermal problems in the clutch due to significant power losses. In the case of a lamella clutch, it is in particular possible to envisage increasing the number of lamellae. The possible reduction of a sports starter regime is generally not desirable. Rather, other means will be considered to ensure the intermediate storage of the maximum power losses in the lamellae or the clutch installation, power thus lost which cannot be removed very quickly.

 The present invention contemplates a process which, independently of the constructive means, allows a particularly efficient starting of the vehicle, in particular the teaching according to the invention is applied to sports starting. The teaching according to the invention is in principle independent of the type of double or multiple clutch. According to

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 type of construction (double wet plate clutch on the one hand or double dry clutch of the friction clutch type on the other) there will be other limiting conditions concerning the load supported by the clutch devices, which must be taken into account in the realization or execution of the process. In the following description of the invention, it is assumed that it is a vehicle transmission line with a double clutch with wet lamellae corresponding to a preferred embodiment of the invention.

 To achieve optimal acceleration of the vehicle, it is proposed to increase the engine rotation speed at the start of the starting phase at as high a speed as possible (if applicable the maximum possible speed). The maximum authorized rotation speed of the engine (generally the maximum authorized rotation speed for the drive unit) is defined by load limits of the clutch installation. From the point of view of the maximum acceleration of the vehicle, the ideal is for the engine to run at its maximum possible speed, that is to say that it is mounted in speed until the engine management cuts out.

 Not only to simplify it is possible to envisage the measure consisting in transmitting the entire clutch torque to the roadway, a torque which must be transmitted by the clutch installation in the case of a sporty start. Indeed, one can provide an anti-skid regulation system (ASR) or even control the clutch installation or regulate it so as to avoid any slippage or to have only a determined slippage at the drive wheels.

 A sporty start can advantageously be triggered by the driver, in particular as indicated in the following manner by the control unit 36 to be launched at the desired instant: the driver actuates the accelerator pedal 38 according to his wish concerning the speed. that he wants to give to the vehicle or to the acceleration of the vehicle. If necessary, the driver fully depresses the accelerator pedal 38. At the same time the driver actuates the operating brake by the corresponding actuation of the brake pedal 46.

 For normal starting operations, which are not designed for particularly large accelerations for the vehicle, actuation of the accelerator pedal would result in movement of the vehicle with regulation of the corresponding clutch torque. However, as the operating brake is applied, the vehicle

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 stay stationary. If after a predetermined time, the control unit 36 does not recognize the significant increase in the speed of rotation at the input of the gearbox or at the drive wheels, the system considers that these are the starting conditions for sports. As a variant or in addition, the order "sport start" could also be deduced from the fact that both the accelerator pedal 38 and the brake pedal 46 have been actuated or are actuated more than that which corresponds to an actuation minimum.

 When the system has recognized the request for a sporty start, insofar as it does not observe any existing overloads (in the case of a wet lamella clutch installation, this is the cooling oil temperature of the 'clutch, which is displayed for the driver by a flashing function lamp (or similar display means) can increase the engine speed to the predetermined speed at the start of actuation of the accelerator pedal 38; the torque supplied by the motor increases correspondingly then, in order to maintain the level of rotational speed reached, part of it is again reduced as shown in the diagrams in FIG. 3 by the curve of rotational speed of the motor nM and the curve of motor torque MM in the first phase (over time). Preferably, the motor speed is adjusted to the set speed. At the same time, the two d clutch devices of the dual clutch in the clutch direction and are kept in a slightly engaged state so that the two clutch devices are in the torque transmission range (see torque curves d '' clutch Mkl and Mk2).

 Already at the start of phase 1, the gearbox input shafts associated with the two clutch devices have already passed a gear that is suitable as a start gear such as the first gear for one of the devices clutch and the second gear for the other clutch device; thus the two clutch devices which now transmit a torque in phase 1, work against the vehicle's braking system. By slightly engaging the two clutch devices, dead time is avoided by the air gap or the like for further actuation of the clutch devices. The clutch devices can thus react very quickly to transmit significant torques in the pursuit of the clutch movement. So it is possible to increase the torque

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 clutch with minimal loss of time. The clutch torque transmitted in phase 1 must be within a range such that even when the sport start request is applied for a prolonged period, that is to say in the case of a prolonged extension over time. phase 1, this results in no damage to the clutch. In the case of wet clutch devices, in phase 1, the cooling power of the clutch devices can be increased to take account of the instantaneous skating mode and in anticipation of the actual sports start.

 By releasing the operating brake, that is to say by releasing the brake pedal 46, the sporty start-up proper is launched. The control unit recognizes this release of the operating brake and uses it as a trigger signal to carry out the actual start (in the example it is a start in the direction of sport start). To start, the two clutch devices are more strongly engaged to transmit engine torque to the gearbox which strongly accelerates the vehicle and thus obtain total engine torque on the gearbox output shafts and thus the drive wheels. entrained. The total engine torque does not result from the simple addition of the couples Mkl, Mk2 transmitted to the gearbox by the two clutch devices; (the values Ml, M2 correspond to phase 2). In fact, it is necessary to take into account the gearbox ratios at the level of each gear ratio and which requires, if necessary, a transformation of the induced torque towards a higher or lower torque level. A torque Mo induced by the gearbox input shaft 1 is transformed by the gear ratio 1 at which this gearbox input shaft is located, for example, to give a torque fxMo. If the same torque is transmitted by the gearbox input shaft 2, connected for example to gear 2, at the output of the gearbox we will have the couple fxMo x iz / ii. The ratio ii / iz corresponds to the change in gear between the first and the second speed ratio, f is the coefficient describing the transformation of the torque in the first speed.

 To have a particularly efficient start it is in itself desirable to use a speed ratio as low as possible because from the torque supplied by the engine, the drive torque is maximized at the output of the gearbox. If according to the invention the engine torque available at least in the first acceleration phase is transmitted by the two clutch devices of the double clutch,

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 this requires, in relation to the total torque Mk supplied to the gearbox, a reduction in the torque available at the output of the gearbox.

After a development proposal corresponding to that of Figure 3, this situation is compensated by the implementation of the second report to transmit part of the total available torque with torque reduction at the output of the gearbox by compensating by the supply additional motor torque from accumulated rotational energy.

 This compensation can best be described with a practical example. If, for example, we start with an engine rotation speed of 6,000 min-l, at the start of sports start-up and an engine torque of 400 Nm corresponding to this engine rotation speed, for the case where the entire torque must be transmitted by the clutch device, there will be a lost power of approximately 250 kW (friction power = difference in rotation speeds [(U / min) x engine torque Nm)] x 21t / 60). This lost power can exceed the possibilities of heat dissipation and storage of heat which depend on the construction so that one cannot carry out such a start-up except at the cost of damage.

The problem now is to reduce the maximum power lost in the starting clutch proper (the clutch device associated with the starting phase, practically at first gear).

 If the engine torque is now transmitted by the two clutch devices, this reduces the maximum values of the lost powers of the clutch devices according to the distribution of the torque between the two clutch devices. From the point of view of a maximum torque at the output of the gearbox it is recommended to reduce the torque transmitted or to be transmitted by the clutch device associated with the starting phase only to a value which corresponds to the possibility of maximum clutch load. In connection with the residual torque transmitted by the other clutch device, there will then possibly be an engine torque at the output of the gearbox which meets the demand.

 If instead we want to have at the output of the gearbox a torque like that which would theoretically be possible by the transmission of the drive torque from the drive unit by a single clutch device and by the ratio starting time without taking into account the clutch overload, then the torque transmitted by the other clutch device can be correspondingly increased

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 (whose gearbox input shaft is connected for example to the second gear ratio).

 However, if it is assumed that the drive unit already supplies the maximum possible engine torque, it is no longer possible to increase the overall torque transmitted to the gearbox. But it is then proposed, before the start of the actual start, to store rotational energy in the engine and to recover the additional torque by braking the rotation of the engine. For this reason in phase 1 of FIG. 3, the speed of rotation of the motor is made to rise above the maximum value, for example at a speed of rotation of 7,000 rpm to exploit the example above.

 If we start from a speed difference of 7,000 rpm and a motor torque of 400 Nm, we can for example engage the starting clutch 1 (the starting speed ratio 1 is applied to its gearbox input shaft) to transmit a torque of 270 Nm. We then obtain on the basis of the data mentioned above by way of example at the level of this clutch device, a lost power of 197 kW.

 If we assume a reduction in gear ratio il / i2 equal to 1.7 between the first and second ratios, the second clutch device (whose input shaft of the gearbox is connected to the second ratio of speed) must be sufficiently engaged to transmit a torque of approximately 220 Nm. This value is calculated from the engine torque and the torque transmitted by the first clutch device as follows: clutch torque 2 = (engine torque - clutch torque 1) x il-12.

 From the digital data of the above example, a power loss of about 160 kW is then obtained at the second clutch device.

 By using the rotational energy, the torque Mk induced overall by the clutch devices whose gearbox is greater than the value of the engine torque MM supplied by the engine so that the engine rotation speed decreases. By bringing the engine speed closer to a target speed (for example the speed 6,000 rpm), the available torque on the input side is completely transmitted to the clutch device 1 in that in the phase 3 the clutch device 2 is completely disengaged and the clutch device is engaged at least so as to transmit the engine torque

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 supplied by the drive unit without further reduction in speed. Reference will be made to the curves given by way of example for the clutch torque of the clutch device 1 (curve Mki) to the clutch torque of the clutch device 2 (curve Mk2) and to the engine torque (curve MM) as well as the rotational speeds ngi, ng2 of the two gearbox input shafts according to FIG. 3. The increases in the curves ngi, ng2 translate the gear ratios in the respective gear ratio relative to each other . According to the proposed procedure, there will be an additional torque recovered by the braking of the drive unit including on the input side of the clutch installation only in phase 2 in FIG. 3. In phase 4, the clutch device 1 then transmits all of the engine torque Mm.

 The clutch devices can be actuated in a controlled manner to adjust the torques Mi, M2 according to FIG. 3 in particular by the control unit 36. In the case of clutch devices with wet lamellae, which are actuated in the manner hydraulic by means of hydraulic sensor cylinders (actuators), relations between the hydraulic pressure and the resulting clutch torque can be applied to the controlled clutch operations; these relationships can be saved in the characteristic fields (preferably adaptable in operation). Correspondingly, in the case of dry clutch devices of the friction disc type, relationships can be established between the actuating stroke and the clutch torque resulting from the controlled actuation.

 FIG. 4 shows an alternative embodiment in which by plugging in a second clutch device, the maximum available drive torque is made available at the start of the acceleration phase at the outlet of the gearbox. The drive torque MM supplied by the drive unit for a constant speed of rotation of the drive unit is transmitted from the start of the starting operation, completely by the clutch device 1 so that due to the starting ratio (in particular the first gear ratio) there will already be a maximum drive torque at the output of the gearbox. The use of the energy of rotation accumulated in phase 1 allows an additional increase of the torque in that in addition one also engages the second clutch device so that the engine will be braked. In phase 2, we thus transmit to the gearbox

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 brakes an additional torque by the clutch device 2 so that there will be an overall drive torque, correspondingly increased at the output of the gearbox. If the engine rotation speed reaches a threshold (for example the rotation speed of 6000 min-l, the output rotation speed could for example be 7000 u / min-l) then the clutch device 2 disengages from so that only the clutch device 1 transmits torque, namely the engine torque supplied by the drive unit (engine) without additional braking.

 The resulting longitudinal acceleration for the vehicle in the case of the example in Figure 3 and that of Figure 4 follows by way of example from the lower diagram. In the case of FIG. 3, the drive torque for phases 2 and 3 and for the initial segment of phase 4 remains constant, which gives a corresponding constant longitudinal acceleration of the vehicle. In contrast to this, in the case of FIG. 4, the drive torque at the output of the gearbox and thus the acceleration of the vehicle in phase 2 is greater than in phase 4. The pursuit of the fall in the longitudinal acceleration of the vehicle which appears in the diagrams during the continuation of phase 4 causes that if the speed of rotation of the input shaft of the gearbox 1 reaches the speed of rotation of the engine, the slip of the clutch device 1 is exhausted and to continue the acceleration of the vehicle it is necessary to use the speed of rotation of the drive unit, that is to say that it is necessary to further accelerate the drive unit. training. Due to the available overall torque of inertia of rotation, this results in a slightly lower longitudinal acceleration of the vehicle for the same engine torque.

 Closing of the clutch devices is done on the examples of FIGS. 3 and 4 at two levels to excite the transmission line twice according to its natural frequencies depending on the gear ratios and this so that by combining the oscillations of the two excitations with a corresponding phase shift we finally obtain a transmission line as free from vibrations as possible.

 The methods described above are carried out by a corresponding control installation with reference to the examples of Figures 1 and 2 by the control unit 36; for this this control unit implements the actuation unit and the double clutch or the clutch devices thereof.

 The invention thus relates, among other things, to a method of starting a vehicle with significant or also significant acceleration.

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 as much as possible based on the transmission line of the vehicle fitted with a double or multiple clutch installation. According to the invention it is proposed that i) first of all, the vehicle being still at a standstill, the speed of rotation of the drive unit is passed to an output rotation speed which is at least in a medium range and preferably in the upper range of a speed range, defined by a minimum speed or idle speed and a maximum speed allowed for the unit d drive, and ii) then the drive unit is operated and the first and second clutch devices are engaged in common until - on the one hand the drive unit provides a torque d drive which is at least in the upper range of a drive torque interval, defined by the zero drive torque and the maximum possible drive torque for the rotational speed level, and other share the first clutch device transmits a first torque and the second clutch device a second torque at the respective input shaft of the gearbox, torques the sum of which also lies at least in the upper range of the torque interval drive defined by the zero drive torque and the maximum possible drive torque for the speed level.

Claims (12)

 1) Method for starting a motor vehicle comprising a transmission line equipped with a drive unit (12), a gearbox (18) having at least two gearbox input shafts and a double or multiple clutch installation (24) for transmitting the torque between the drive unit and the gearbox, the clutch installation having a first clutch device (26) associated with a first shaft d gearbox input (20) and a second clutch device (28) associated with a second gearbox input shaft (22), which can be actuated selectively and independently in the clutch direction and / or in the declutching direction to induce a drive torque of the drive unit in the gearbox, selectively via the first input shaft and / or the second input shaft of the gearbox, whose drive torque in troduit is transmitted as a function of an instantaneous gear ratio state of the gearbox (18) on at least one gearbox output shaft (54), if necessary after transforming the torque correspondingly according to a ratio for instant reduction of a gear ratio passed with respect to the respective input shaft of the gearbox, and the torque of the output shaft of the gearbox being transmitted to the drive wheels of the vehicle, method in which during a start-up phase by the first and the second clutch device at least one of the two operates with slip and the two clutch devices transmit simultaneously according to an instantaneous torque transmission capacity clutch devices, the drive torque to the first and second gearbox input shafts, adjusting for the two gearbox input shafts each time a ratio of speed, to transmit the drive torque transmitted to the respective gearbox input shaft correspondingly to the respective gearbox ratio up to the gearbox output shaft so that the gearbox output shaft receives a corresponding total drive torque for driving the drive wheels, characterized in that i. first of all the vehicle being still at a standstill, the speed of rotation (nM) of the drive unit (12) is driven to an output speed level which is situated in a medium zone, preferably - <Desc / Clms Page number 20>  rence in an upper zone, of a rotation speed interval defined by a minimum rotation speed or idle rotation speed and a maximum rotation speed authorized in the drive unit, and ii. then the drive unit (12) and the first (26) and the second (28) clutch device are operated in common by engaging them until - on the one hand the unit d drive provides a drive torque (MM) that is at least in an upper region of a drive torque interval defined by the zero drive torque and a maximum possible drive torque for the speed level rotation, and - on the other hand the first clutch device transmits a first torque (Mi) and the second clutch device a second torque (M2) to the respective input shaft of the gearbox, the sum (Mk) of the torques also corresponding at least to an upper range of the drive torque interval defined by the zero drive torque and the maximum possible drive torque for the speed level.  2) A method of starting a motor vehicle according to claim 1, characterized in that before engaging the first and second clutch devices together, at least one and preferably the two devices are engaged. 'clutch (26,28) in a prior manner, until the clutch device concerned transmits a torque significantly smaller than the first and second torque but somewhat exceeding the drag torque produced.  3) A method of starting a motor vehicle according to claim 1, characterized in that the sum (Mk) of the first and second torque is greater than the drive torque (MM) provided by the drive unit at of rotational speed on condition that a drive rotational speed remains essentially constant, so that the rotational drive speed <Desc / Clms Page number 21>  tion (nM) fall during continued clutching of the two clutch devices.  4) Method for starting a motor vehicle according to claim 3, characterized in that if the drive rotation speed approaches a threshold rotation speed level located below the output rotation speed level or reaches this level, of the two clutch devices, the second (28) is disengaged and the first (26) continues to be engaged or is maintained in the instant engaged state so that the drive speed does not go below the threshold speed level or does not go down significantly below this level.  5) A method of starting a motor vehicle according to claim 4, characterized in that the lowest speed ratio of the past speed ratios is associated with the first clutch device (26).  the first couple (Mi) is greater than the second couple (M2).

 6) Method for starting a motor vehicle according to one of claims 1 to 5, characterized in that 7) Method for starting a motor vehicle according to one of claims 1 to 6, characterized in that the first torque (Mi) is less than the drive torque (MM) supplied by the drive unit at the rotational speed level on condition that a drive rotational speed remains essentially constant.  8) A method of starting a motor vehicle according to claim 4, characterized in that <Desc / Clms Page number 22>  the total drive torque produced on the output shaft (54) of the gearbox, from the first and second torque (Mi, M2) is substantially the same as a drive torque applied to a shaft gearbox output from the torque transmitted by the first clutch device to the first gearbox input shaft after disengagement of the second clutch device (28) and continuation of the clutch of the first clutch device clutch (26).  9) A method of starting a motor vehicle according to claim 1, characterized in that the first torque (Mi) is substantially equal to the torque (MM) supplied by the drive unit at the rotational speed level with a speed of drive rotation remaining essentially constant. 10) Method for starting a motor vehicle according to one of claims 4 to 7 or according to claim 9, characterized in that the total driving torque obtained on the gearbox output shaft, from the first torque (Mi) and second torque (M2) is greater than the drive torque of the gearbox output shaft which is obtained by the first clutch device (26) transmitting the torque to the first input shaft (20) of the gearbox after disengagement of the second clutch device (28). 11) Method for starting a motor vehicle according to claim 1, characterized in that if the speed of rotation of the first gearbox input shaft reaches the threshold speed level, the common speed continues d '' be accelerated with the drive rotation speed. 12) Method for starting a motor vehicle according to claim 1, characterized in that the two clutch devices (26, 28) can be equipped with several stages, preferably two stages, for transmitting the first torque (Mi ) and the second torque (M2), and the multi-stage clutch is <Desc / Clms Page number 23>  made so that the excitations of oscillations of the transmission line compensate at least partially because of the different engaged stages. 13) Method for starting a motor vehicle according to claim 1, characterized in that the method is carried out under the control / regulation of a control installation (36) of the motor vehicle. 14) Method for starting a motor vehicle according to claim 13, characterized in that the execution of the starting process is triggered in that first of all - a displacement signal transmitter (38) of the vehicle, if applicable if necessary the accelerator pedal (38) is actuated to exceed a threshold value in the direction of activation or increase in speed of the drive unit and simultaneously a brake signal transmitter is actuated (46 ) of the vehicle, if necessary the brake pedal (46) more strongly than a minimum value in the direction of activation of the vehicle braking system and, - then, maintaining the actuation of the signal transmitter the brake signal transmitter (46) is actuated in the direction of essentially complete activation of the braking system. 15) A method of starting a motor vehicle according to claim 14, characterized in that the actuation of the displacement signal transmitter (38) is stronger than the threshold value in the direction of activation or d '' a rise in speed of the drive unit at the same time as the actuation of the brake signal transmitter (46) is stronger than the minimum value in the direction of activation of the brake system, the rotation speed of the drive is driven at the output rotation speed and if necessary the clutch of at least one of the clutch devices (26,28) is triggered beforehand, and the actuation of <Desc / Clms Page number 24>  the brake signal transmitter (46) in the direction of essentially complete deactivation of the brake system triggers the clutch of the first clutch device (26) and the second clutch device (28) to transmit the first couple (Mi) and the second couple (M2). 16) A method of starting a motor vehicle according to claim 11, characterized in that it is executed by a clutch installation (24) with lamellae of which the first and the second clutch device are produced each time preferably for a wet lamella clutch device (24,26).  17) Method for signaling a special request to start a vehicle driver transmitted to the control unit (36) of the vehicle designed for a corresponding control of a drive unit (12) and / or a gearbox (18) and / or for a clutch installation (24) transmitting the torque between the drive unit and the gearbox or / and a brake system as well as if necessary other components or functionalities of the vehicle in a special start-up phase of the vehicle corresponding to this start-up request, if necessary for a sport start-up, and to trigger this start-up operation, characterized in that first of all a vehicle movement signal transmitter (38), if applicable, the accelerator pedal (38) more strongly than a threshold value in the direction of activation or ramp-up of the drive unit and simultaneously act Apply a brake signal transmitter (46) from the vehicle, if necessary a brake pedal (46) more strongly than a minimum value in the direction of activation of the vehicle brake system, and then actuation with the displacement signal transmitter (38) held, the brake signal transmitter (46) is actuated in the direction of essentially total deactivation of the brake system if necessary by releasing the brake pedal ( 46) to signal the start request and trigger it according to this request. 18) Motor vehicle control installation designed for the appropriate control of a drive unit (12) and / or a gearbox <Desc / Clms Page number 25>  gear (18) and / or a clutch installation (24) for the transmission of torque between the drive unit and the gearbox and / or a brake system as well as other components or functionalities of the vehicle for a special starting operation, if necessary a sport starting of the vehicle, and / or for detecting a corresponding request from the driver, characterized in that the control installation (36) is designed to execute the start-up operation according to the method of one of claims 1 to 16 or / and detecting the driver's request according to the method of claim 17 and then, if necessary, triggering the corresponding start-up operation in accordance with claim 17 .  19) w vehicle equipped with a control installation (36) according to claim 18. <Desc / Clms Page number 26> TRANSLATION FIGURE 3 1) Report of past speed.  2) Engine speed. 3) Motor. 4) Rotation speed. 5) Input 1 of the gearbox. 6) Clutch 1. 7) Clutch 2. 8) Braking torque. 9) Motor torque.  10) Setpoint torque.  11) Longitudinal acceleration.  12) Time.  TRANSLATION FIGURE 4 1) Report of past speed.  2) Engine speed.  3) Motor.  4) Rotation speed.  5) Input 1 of the gearbox.  6) Clutch 1.  7) Clutch 2.  8) Braking torque.  9) Motor torque.  10) Setpoint torque.  11) Longitudinal acceleration.  12) Time.