GB2327108A - Automatic clutch having an addition brake sensor which prevents system failures - Google Patents

Abstract

An automatic clutch 3, for a motor vehicle, comprises a control unit 13 that adjusts, via a computer unit 13a, the torque transferred by the clutch 3 in dependance upon inputs from, for example, engine electronic unit 50 and ABS electronic unit 60 which processes signals from brake sensor 41. The units 13, 50 and 60 are connected through a data bus 70 which transfers first brake operating data from the ABS unit 60 to the control unit 13. If a failure occurs in the data bus 70, the control unit 13 switches into emergency mode, which controls a creeping forward of the vehicle, and second brake operating data is supplied from the brake sensor 41 to the control unit 13 by digital brake input 71. If the brake input 71 signals that brake activation exist the clutch 3 is disengaged and if no activation exist the clutch is engaged. Other sensors are used to detect, for example, wheel speeds, engine speeds, throttle valve position, gear position etc. The control unit 13 operates an electric motor 12 which, via gearing, adjusts a position of a master cylinder 11 that is connected to a slave cylinder 10 by a hydraulic line 9.

Description

2327108 MOTOR VEHICLE WITH AUTOMATIC CLUTCH The invention relates to a

motor vehicle with a gearbox and a device for controlling an automatic clutch.

Systems of this kind are used for example in motor vehicles with automatic clutch and/or automatic gearbox wherein the clutch is mounted between the engine and drive wheels in the drive train of the motor vehicle. With such vehicles a control of a creeping process can be carried out by deliberately adjusting a torque transferable by the clutch so that the vehicle starts to creep slowly forward for example. The creeping process can be introduced particularly when with the engine running and the gear engaged the operating brake or hand brake of the vehicle is not operated. The creeping process can be scaled down or ended when the brake is operated. Motor vehicles of the kind mentioned above have been known for example through DE 05 44 26 260.

with motor vehicles of this kind a connection takes place between for example sensors and the control unit of the automatic clutch through signal connections such as for example through a data bus, such as for example CAN bus.

Through such data bus lines vehicle operating parameters and sensor signals or values can be transferred to a control unit, such as for example the control unit of the automatic clutch or an engine control unit or a control unit of an anti-brake locking system (ABS). Similarly different control units can also communicate through a data bus.

If in certain operating situations a defect exists in the data bus line, for example through a break in the cable or through a short circuit then no information on the actual driving state or operating state can be passed for example SP2129. P3 19/03/98 from the brake by means of a brake operating sensor inter alia to the control unit of the automatic clutch.

In such operating situations, for example in the case of a defective data bus, emergency driving modes can be initiated by the control unit to substantially maintain the driving ability of the motor vehicle despite restricted operating comfort and driving comfort.

If there is no defect in the data bus then the driver can for example with the vehicle stationary and the automatic clutch system intact engage a gear in the gearbox wherein then with the engine running and the brake not activated the control unit builds up the torque transferable by the clutch to creep the vehicle forward and scales it down again when the brake is operated.

With a breakdown in the data bus the control unit of the automatic clutch would, with the engine running and gear engaged, control the clutch so that a torque transferable by the clutch is built up again so that the vehicle moves. If for example the driver operates the operating brake or parking brake then the control unit of the automatic clutch in the event of a defect in the data bus does not however recognise the brake operation and the transferable torque for creeping forward or for example even for driving off is furthermore deliberately controlled.

The driver thus recognises no reduction in the torque for creepingforward and experiences a system behaviour with which he is unfamiliar. He would in this operating situation operate the vehicle brake still heavier so that the vehicle is not set in motion though the transferable torque, which is built up by the automatic clutch. The result of this is that the engine would stall and this would also lead to a breakdown of the vehicle if the SP2129. P3 19/03/98 driver is not aware that in the situation of the nondesirable driving off or creeping forward he must first engage gear if he would like to set the vehicle in motion. The driver does not indeed automatically know in the event of a failure of the bus system that the brake operation is not recognised by the control unit and thus another procedural step is to be required of him. Thus situations which are critical to safety can arise which can occur with a failure of the data bus.

The object of the invention is therefore to provide a vehicle with a device for controlling an automatic clutch in the drive train where for example in the event of a failure of the data bus the vehicle can nevertheless be safely driven off or braked and/or a creeping process of the vehicle can be reliably controlled.

Furthermore it is the object of the invention to provide motor vehicles of the kind mentioned above with a device for controlling an automatic clutch which compared to the known devices according to the prior art has increased safety, more particularly in the event of system breakdowns or partial system failures.

This is achieved according to the invention in that the control unit has an additional separate signal input through which a further brake operation information is passed from a brake operating sensor to the control unit which registers the brake operating information.

It can be particularly expedient if the control unit switches into emergency driving mode if the signal connection to at least some individual sensors such as to the brake operating sensor, and/or electronics units is interrupted or damaged and the control unit uses the brake operating information through the separate signal input SP2129. P3 19/03/98 with the presence of an emergency driving mode to control the torque transferable by the clutch. Furthermore it can be expedient if the control unit switches into an emergency driving mode when the data bus for transferring sensor signals such as the signal of the brake operating sensor is defective or damaged and the control unit uses the brake operating information through the separate signal input with the presence of an emergency driving mode to control the torque transferable by the clutch.

In a particularly expedient design of the invention it is thereby proposed that with a gear engaged in the gearbox the control unit with an activated brake holds the clutch disengaged or disengages same so that the vehicle does not creep forward and with a non-activated brake engages the clutch at least partially or holds the clutch engaged so that the vehicle creeps forward.

Furthermore it is advantageous if the control unit only 20 with some gears engaged in the gearbox with the brake activated holds the clutch disengaged or disengages the clutch and with the brake non-activated engages the clutch at least in part or holds the clutch engaged and with other gears engaged in the gearbox closes the clutch as a function of for example the time.

Furthermore it can be expedient if the control unit only with first gear or reverse gear engaged in the gearbox with the brake activated disengages the clutch or holds the clutch disengaged and with a non-activated brake engages the clutch at least partially or holds the clutch engaged.

It can also be proposed accordingly that the control unit 35 only with a greater transmission ratio set in an infinite gearing or with a reverse driving setting with a brake SP2129.P3 19/03/98 96/E0/6T Ed 6ZTZdS T#5no-TTI:1 GDeld saXR; 'UOTZ-eAT;DR-UOU T4;TM Se 'UOTIPAT;DP GXPaq Gq; JO UOT-4RUTWaGZ R qZTM aO GXPJq all; JO UOT:;RAT;:)R qzTm To;n1D qq; go ZuGwa5e5uasTp ao/puR:luawa6P6ua Gqz;T UaTpadxG aq Aqaaatp URD II xoqaRG5 aT.: ui pa525ua apa5 aq-4 uo az:)uapuadap uT aoRTd se:ri qnznlD atl-4 go zuaw@5L.5ua ZUGWa5R5UaSTP G-q; JT:4UaTpGdxa AlIRnba sT ji -PG6PBUG IT sploq -zo tID:n-ED aq-4 s;?BLBua aXle-zq PGZL-AT--IDL--UOU P q:TM PUP awes sa5-esuas-rp ao P9F5PBUaSTP T)-.njo aT.4 sploq a,{Raq PG-42AT:4DR UP qzTm xoqauaS Gil.:

UT paúL-Bua s-iL-GB I-EL. xlzTm 4Tun loaluoD aq; _;-p;ua-rpadxG aq ueD zT aan;Rag GAT:UaAUT Zaqlang R OZ BUTpaODDY OE -pa5R5u@sTp;ou sT qz);n1D aq; GDUTS UTPWaa URD UOT;Dung a,Taq allTEUG UP aXRaq BUT;RaGdO Gn: JO UOT;RATIDR TI;-pm snq P::1Pp aR; go G-Tnl-pL-g _JO:lUaAG Gl'I UT 'SOT'Zel 0Z UOTSSTWSU-ea': aGMOI T'4TM SP 'SaRGE aGq5TR q4TM GSIgn R qons UT -TOJ sTqI;uawaldWT 01 SnOG5e;UPAPR A1BUTPUOdSaaa0D aq UPD:T SUOS2aa A.ZGIL-S 20a 'PG;PAGdO ST GXPaq aR.4 uaRm uaddpR iou saop TDznl) Gq; go -4UaWG5RSUGSTP P S2PG5 2GT46TI UT:ienz os Tp;n1D GRZ JO 10a;UOD GqZ UBT9Gp 0-4 ZUGTp@dXa ST Gq upo nT aDuan1JUT OU UOTJUaAUT aq-4 OZ 5UTPaODDR Set{ aX2aq 5UT;RaadO G11:4 JO 1LRUETS aq; 'SOT1RJ UOTS9TWSURal -1,9M01 T4;TM SR 'SJIL2a15 -TaTI5TI TI;-PM SaSUP-T BUTATap WC gI SOT'4Pa UOTSSTWSURa-4 OT R6T11 se qz)ns SOT-4le-1 UOTSSTU1SURal gJ0 5UTAT-Tp GTIZ 01 9 WT1PI:D BUTP-1e5G-T -TplnDT:-IL-d UT SaagG-T USTSap GT4Z UTG-TGqm saxoc[-TpafS zz:)lezuoD zlac[ AalInd guoD sv iq:Dns 'SFDUT-TL-aJB Glc[PisnIpL. AIG.4TuTgur o:l ao sasieT-d UOTSSTWSUR-TZ PaU-r_;ap A1PGXTJ lqzTm saxoq-Te@5 paddans oz paTIdde aq uleD asn aqi pa6E6ua qD.4n1D aqz SPI0q aO AlIRTzied:sRal Ze qDzn1D Gqz saBR6ua aXeaq PG-4RATZDE-UOU R qZTM PUR awes SG6PBUGSTP -10 pa6L2BUaSTP TD:nlz:) Gq-4 sploTI pa,4L-A-r:DL- - 9 time-controlled and/or speed-controlled and/or slipcontrolled functions, such as for example slopes. This can be designed in a particularly advantageous way so that the functions or slopes have a parameter which is geardependent so that for example in dependence on the engaged gear and/or gear to be engaged the clutch is opened or closed faster or slower or with a different rise. According to the inventive idea it can be expedient if the signal input like the separate additional signal input, is a digital input of the control unit.

It is also advantageous in the case of a motor vehicle if the control unit is in signal connection with other electronics units, such as an engine electronics and/or ABS electronics unit. It can likewise be expedient if the control unit is supplied through two signal inputs with the brake operation information.

The invention will now be explained with reference to the drawings by way of example. In the drawings:

Figure 1 is a diagrammatic vehicle; Figure 2 is a diagram; and Figure 3 is a diagram.

illustration of a Figure 1 shows diagrammatically a vehicle 1 with a drive unit 2,such as an engine or internal combustion engine.

Furthermore a torque transfer system 3 and gearbox 4 are shown in the drive train of the vehicle. In this embodiment the torque transfer system 3 is mounted in the force flow between the engine and gearbox wherein a drive moment of the engine is transferred through the torque transfer system to the gearbox and from the gearbox 4 on SP2129. P3 19/03/98 the output side to an output shaf t 5 and to an axis 6 on the output side as well as to wheels 6. The clutch can also be mounted after the gearbox.

The torque transfer system 3 is formed as a clutch, such as friction clutch, dry friction clutch, multi-plate clutch, magnetic powder clutch or converter bridging clutch wherein the clutch can be a self-adjusting, wearcompensating clutch. The torque transfer system can furthermore be formed as a driving clutch and/or turning set clutch for changing direction and/or safety clutch with a deliberately controllable transferable torque. The torque transfer system can be a dry friction clutch or a wet-running friction clutch which runs for example in a fluid. Similarly it can be a torque converter.

The gearbox 4 is shown as a manual shift gear such as a variable-speed stepped gear. According to the inventive idea the gearbox can however also be an automated shift transmission which can be shifted automatically by means of an actor. By automated shift transmission is substantially meant an automatic gearbox which is shifted with a break in the pulling force and the shift process of the gear transmission ratio is carried out controlled by means of at least one actor. Furthermore an automatic gearbox can also be used wherein an automatic gearbox is a gearing substantially without a break in the pulling force during the shift process and which is as a rule built up through planetary gear stages. Furthermore an infinitely adjustable gearbox can be used such as for example a cone pulley belt contact gearbox. With the gearbox one gear or one transmission can be shifted or engaged from a number of gears or transmissions.

The torque transfer system 3 has a drive side 7 and an output side 8 wherein a torque is transferred from the SP2129. P3 19/03/98 8 - drive side 7 to the output side 8 in that the clutch disc 3a is force- biased by the pressure plate 3b, plate spring 3c and disengagement bearing 3e as well as the flywheel 3d. For this biasing the disengagement lever 20 is 5 operated by means of an operating unit, such as actor 13b.

The control of the torque transfer system 3 is carried out by means of a control unit 13, such as control device, which can comprise the control electronics 13a and the actor 13b. In another advantageous design the actor and control electronics can also be mounted in two different structural units such as housings.

The control unit 13 can contain the control and power electronicsfor controlling the electric motor 12 of the actor 13b. It can thereby advantageously be reached that the system requires as a single structural chamber the structural chamber for the actor with electronics. The actor consists of a drive motor 12, such as electric motor, wherein the electric motor 12 acts through a gearing, such as worm gear or spur wheel gear or crank gear or threaded spindle gear on a master cylinder 11. The action on the master cylinder can take place direct or through a rod linkage.

The movement of the output part of the actor such as of the master cylinder piston 11a is detected by a clutch path sensor 14 which detects the position or setting or speed or acceleration of a value which is proportional to the position or engagement position or respectively the speed or acceleration of the clutch. The master cylinder 11 is connected by a pressurised medium line 9 such as a hydraulic line to the slave cylinder 10. The output element 10a of the slave cylinder is in active connection with the disengagement lever or disengagement means 20 so that a movement of the output part 10a of the slave SP2129.P3 19/03/98 cylinder 10 causes the disengagement means 20 to be likewise moved or tilted in order to control the torque transferable by the clutch 3.

The actor 13b for controlling the transferable torque of the torque transfer system 3 can be operated by pressurised medium, ie it can be equipped with a pressurised medium master and slave cylinder. The pressurised medium can be for example a hydraulic fluid or pneumatic medium. The operation of the pressurised medium master cylinder can be provided by an electric motor wherein the electric motor 12 can be controlled electronically. The drive element of the actor 13b can also be in addition to an electromotorized drive element another drive element, such as for example operated by pressurised medium. Furthermore magnetic actors can be used to set the position of an element.

With a friction clutch the control of the transferable 20 torque is carried out in that the contact pressure of the friction linings of the clutch disc takes place deliberately between the flywheel 3d and pressure plate 3b. Through the position of the disengagement means 20 such as disengagement fork or central selector member the force biasing of the pressure plate and friction linings respectively can be controlled deliberately whereby the pressure plate can thereby be moved and set and fixed anywhere between two end positions. The one end position corresponds to a fully engaged clutch position and the 30 other end position to a fully disengaged clutch position. In order to control a transferable torque which is for example less than the engine moment momentarily existing, a position of the pressure plate 3b can be controlled for example which lies in an intermediate area between the two 35 end positions. The clutch can be fixed in this position by the deliberate control of the disengagement medium 20.

SP2129. P3 19/03/98 - Transferable clutch moments can however also be controlled which lie defined above the momentarily arising engine moments. In such a case the engine moments actually arising can be transferred wherein the torque irregularities in the drive train in the form of for example torque peaks are damped and/or insulated.

In order to control such as regulate the torque transfer system and more particularly the torque transferable by the clutch, sensors are used which monitor at least at times the relevant values of the entire system and supply the condition values, signals and measured values required for control which are processed by the control unit wherein a signal connection can be provided and can exist with other electronics units such as for example with an engine electronics 50 or an electronics of an anti-lock braking system (ABS) 60 or an anti-slip regulation system (ARS). The sensors detect for example speeds, such as wheel speeds, engine speeds, the position of the load lever, the throttle valve position, gear position of the gearbox, shift intent and further characteristic values specific to the vehicle. The signal connection between the individual control units 13, 50 and for example 60 takes place through a data bus 70 which can be for example: a CAN bus.

Figure 1 shows that a throttle valve sensor 15, an engine speed sensor 16, as well as a tacho sensor 17 can be used and pass on measured values and data to the control apparatus. The electronics unit such as computer unit of the control unit 13a processes the system input values and sends control signals onto the actor 13b.

The gearbox is formed as a step change gear wherein the transmission stages are changed by a shift lever or the gearbox is operated or controlled by this shift lever.

SP2129. P3 19/03/98 Cz Furthermore at least one sensor 19b is arranged on the operating lever, such as shift lever 18, of the manual gear shift, and detects the shift intent and/or gear position and passes this onto the control device. The sensor 19a is attached to the gearbox and detects the actual gear position and/or shift intent. The shift intent recognition using at least one of the two sensors 19a, 19b can be carried out in that the sensor is a force sensor which detects the force acting on the shift lever. Furthermore the sensor can also however be formed as a path or position sensor wherein the control unit detects a shift intent from the time change of the position signal.

The control apparatus is in signal connection with all the sensors at least at some time and evaluates the sensor signals and system input values in the mannerand way whereby the control unit sends control or regulating commands to the at least one actor in dependence on the actual operating point. The drive element 12 of the actor such as electric motor receives from the control unit which controls the clutch operation a setting value in dependence on the measured values and/or system input values and/or signals of the attached sensor unit. To this end a control program is implemented in the control apparatus as hard and/or software and evaluates the incoming signals and calculates or determines the output values from comparisons and/or functions and/or characteristic fields.

The control device 13 advantageously has an implemented torque determining unit, a gear position determining unit, a slip determining unit and/or an operating state determining unit or is in signal connection with at least one of these units. These units can be implemented by control programs as hardware and/or software so that by means of the incoming sensor signals it is possible to SP2129. P3 19/03/98 - 12 determine the torque of the drive unit 2 of the vehicle 1, gear position of the gearbox 4 as well as slip which prevails in the area of the torque transfer system and the actual operating state of the vehicle. The gear position- determining unit determines the gear actually engaged from the signals of the sensors 19a and 19b. The sensors are thereby attached to the shift lever and/or to setting means inside the gearbox such as for example a central selector shaft or shift rod and these detect for example the position and/or speed of these component parts.

Furthermore a load lever sensor 31 can be mounted on the load lever 30, such as accelerator pedal which detects the load lever position. A further sensor 32 can function as an idling switch, i.e. with an activated accelerator pedal such as load lever, this idling switch 32 is switched on and with a non-activated signal it is switched off so that through this digital information it can be identified whether the load lever such as accelerator pedal is operated. The load lever sensor 31 detects the degree of activation of the load lever.

Figure 1 shows in addition to the accelerator pedal 30, such as load lever and the sensors in connection therewith 25 a brake operating element 40 for operating the operating brake or parking brake such as brake pedal, hand brake lever or hand or foot operated operating element of the parking brake. At least one sensor 41 is mounted on the operating element 40 and monitors the operation thereof. 30 The sensor 41 is formed for example as a digital sensor such as switch wherein this detects that the operating element is operated or not operated. A signal device such as brake light is in signal connection with this sensor to signal that the brake is activated. This can take place 35 both for the operating brake and for the parking brake. The sensor can however also be formed as an analogue SP2129. P3 19/03/98 sensor wherein such a sensor such as for example a potentiometer determines the degree of operation of the operating element. Also this sensor can be in signal The sensor 41 is in 5 signal connection for example with the control and electronics units through the data bus 70. Furthermore the control unit has a separate signal input 71 through which the brake-operating sensor 41 is directly in signal connection with the control unit.

connection with a signal device The control unit receives a first brake operating data through a first signal connection, such as the data bus for example from the ABS control unit 60 and additionally through the digital brake input 71 a further second brake operating data. The signal of the digital brake input 71 can arise in normal operation and also in emergency driving mode in the event of a defective transfer of the brake information through the data bus. The control unit of the automatic clutch thus receives the brake operating data twice through two different signal inputs. These signals of the brake operating data are received and evaluated by the control unit. Through the input of the brake operating data through two signal inputs it is possible with the failure of the first brake operating data to switch into an emergency driving mode which controls for example the creeping forward of the vehicle when the brake is not operated and prevents this creeping when the brake is operated.

Figure 2 shows a diagram 100 for illustrating a control plan for controlling the torque transferable by the clutch. In block 101 the process for control or regulation is started in a first step. In block 102 it is checked in a further step whether the brake operating sensor and/or the signal connection such as data bus are working properly between the brake operating sensor and SP2129. P3 19/03/98 - 14 the control unit or the data bus or whether there is a defect or fault or failure. This can take place for example in that a comparison is made whether all the signals exist or whether one signal lies outside an ideal value range. It is then evaluated whether a defect is present. If this is not the case then at block 108 the process is ended. If there is a defect then an emergencydriving mode is activated in block 103.

Then in block 104 the brake operating signal of the brake operating sensor 41 is detected at the separate preferably digital input 71 of the control unit 13 and evaluated by the control unit. In block 105 it is evaluated whether a brake activation exists. If the brake activation exists in emergency driving mode then the clutch is disengaged, that is the torque transferable by the clutch is reduced in block 106 and if no brake activation exists then the clutch is engaged in block 107, that is the torque transferable by the clutch is increased. In block 108 the process is terminated whereby the procedure according to diagram 100 is run through again in each time beat and the control takes place according to the operating conditions of the vehicle. By way of example the procedure is run through in a millisecond beat of 1 ms to 1000 ms, preferably 5 ms to 50 ms.

Figure 3 shows a diagram 200 for illustrating a control sequence for controlling the torque transferable by the clutch. In block 201 in a first step the process is started for control or regulation. In block 202 in a further step it is checked whether the brake operating sensor and/or data bus are working properly or whether a defect or fault or breakdown exists. This can take place for example in that a check is made whether all the signals are present or whether a signal lies outside of an ideal value range. It is then evaluated whether a defect SP2129. P3 19/03/98 is - is present. If this is not the case then the method is ended at block 209. If there is a defect then an emergency driving mode is activated in block 203.

Then the brake operating signal of the brake operating sensor 412 is detected at the separate preferably digital input 71 of the control unit 13 and evaluated by the control unit.

In block 205 a gear position sensor 19a or a shift lever position sensor 19b is interrogated and the gear actually engaged in the gearbox is determined from the sensor signals. If the engaged gear is first gear or reverse gear R then the process continues at block 206. If the engaged gear is for example second gear or a higher gear with lower transmission ratio then the process is terminated.

In block 206 it is evaluated whether a brake activation exists. If the brake activation exists in emergency driving mode then the clutch is disengaged, i.e. the torque transferable by the clutch is reduced in block 207 and if there is no brake activation then the clutch is engaged in block 208, that is the torque transferable by the clutch is increased. The process is terminated in block 209.

It is thereby reached that the driving off processor creeping process is easier for the driver and made safer through the control unit even in the event of a failure or defect of partial systems, such as for example the data bus. In emergency driving mode the clutch remains opened or is opened with an activated brake and in the event of a non-activated brake the clutch remains closed or is closed. In gears 2 to 5, 6 the signal of the brake, such as operating brake can have no influence on the control of SP2129. P3 19/03/98 the clutch. The clutch can in such a case be closed through a gear- dependent slope as a function of the speed, such as engine speed or gearbox speed, or time or the clutch remains closed. With a timedependent and for example also gear-dependent slope for closing the clutch the engagement speed can amount to 10 Nm/s to 300 Nm/s, preferably 40 Nm/s to 200 Nm/s. The selected slopes can also be different for the case of a changing-down process for example from 3 d gear to 2 nd gear from the selected slopes with a changing-up process for example when changing from 3 1d gear to 4t1' gear. The vehicle thus has an engine brake with closed clutch even with a data bus breakdown or with another defect. Through the deliberate control of the transferable torque with brake activation in a starting gear with a controlled creeping the creeping can be deliberately broken off or carried on further.

Detecting a fault or failure of the data bus can be identified by monitoring the data bus signals for example.

If over a predetermined time period of some milliseconds (10 ms to 500 ms) there is no data on the data bus then a f ailure of the data bus can be detected or established. Likewise a failure of the brake operating sensor can be established if a fault signal is transferred on the data bus such as for example CAN bus which signals a failure of the sensor signal or sensor. If the signal connection from the sensor is damaged then for example by making a comparison with the signal at the separate signalinput it can also be determined whether the signal is faulty or not.

The control unit can carry out a control with an open control path with or without adaptation. In a f urther embodiment it is possible to carry out a regulation with a closed regulating path with return. Similarly a control SP2129.P3 19/03/98 process with a control part with adaptation and with a regulation part can also be provided.

The patent claims filed with the application are proposed wordings without prejudice for obtaining wider patent protection. The applicant retains the right to claim further features disclosed up until now only description and/or drawings.

in the References used in the sub-claims refer to further designs of the subject of the main claim through the features of each relevant subclaim; they are not to be regarded as dispensing with obtaining an independent subject protection for the features of the sub-claims referred to.

The subjects of these sub-claims however also form independent inventions which have a design independent of the subjects of the preceding claims.

The invention is also not restricted to the embodiments of the description. Rather numerous amendments and modifications are possible within the scope of the invention, particularly those variations, elements and combinations and/or materials which are inventive for example through combination or modification of individual features or elements or process steps contained in the drawings and described in connection with the general description and embodiments and claims and which through combinable features lead to a new subject or to new process steps or sequence of process steps insofar as these refer to manufacturing, test and work processes.

SP2129. P3 19/03/98 - 18

Claims (13)

1. Motor vehicle with a gearbox and device for controlling an automatic clutch in the drive train, with an operating unit controllable by a control unit for adjusting the torque transferable by the clutch, the control unit is in signal connection with sensors, such as a brake operating sensor, and other electronics units, such as an engine electronics and/or ABS electronics unit, for example through signal lines and/or a data bus, characterised in that the control unit has an additional separate signal input through which a further brake operating information is sent from a brake operating sensor to the control unit which registers the brake operating information.

2. Motor vehicle according to claim 1 characterised in that the control unit switches into emergency driving mode when the signal connection to at least individual sensors such as to the brake operating sensor, and/or electronics units is interrupted or damaged and the control unit uses the brake operating information through the separate signal input with the presence of emergency driving mode to control the torque transferable by the clutch.

3. Motor vehicle according to claim 1 characterised in that the control unit switches into emergency driving mode when the data bus for transferring sensor signals, such as the signal of the brake operating sensor, is defective or damaged and the control unit uses the brake operating information through the separate signal input with the presence of emergency driving mode to control the torque transferable by the clutch.

SP2129.P3 19/03/98 - 19

4. Motor vehicle according to one of claims 1 to 3 characterised in that with a gear engaged in the gearbox and with the engine running the control unit with the brake activated holds the clutch disengaged or disengages same so that the vehicle does not creep forward and with the brake not activated at least partially engages the clutch or holds the clutch engaged so that the vehicle creeps forwards.

5. Motor vehicle according to claim 4 characterised in that only when some gears are engaged in the gearbox does the control unit hold the clutch disengaged or disengages same when the brake is activated and when the brake is not activated at least partially engages the clutch or holds the clutch engaged and in the case of other gears engaged in the gearbox closes the clutch as a function of for example the time.

6. Motor vehicle according to claim 4 characterised in that the control unit only holds the clutch disengaged or disengages same when first gear or reverse gear is engaged in the gearbox and the brake is activated and at least partially engages the clutch or holds the clutch engaged when the brake is not activated.

7. Motor vehicle according to claim 4 characterised in that the control unit holds the clutch disengaged or disengages same with all gears engaged in the gearbox with the brake activated and at least partially engages the clutch or holds the clutch engaged when the brake is not activated.

8. Motor vehicle more particularly according to one of the preceding claims characterised in that the extent of disengagement and/or engagement or the speed of SP2129. P3 19/03/98 - 20 disengagement and/or engagement of the clutch takes place in dependence on the gear engaged in the gearbox.

9. Motor vehicle according to any of the preceding claims, characterised in that the engagement and/or disengagement of the clutch in the event of brake activation or at the end of brake activation, such as nonoperation, takes place through time-controlled and/or speed- controlled and/or slip-controlled functions. such as 10 slopes.

10. Motor vehicle according to claim 1 characterised in that the signal input is a digital input of the control unit.

11. Motor vehicle according to one of the preceding claims, characterised in that the control unit is in signal connection with other electronics units, such as an engine electronics and/or ABS electronics unit.

12. Motor vehicle according to one of the preceding claims, characterised in that the control unit is supplied through two signal inputs with the brake operating information.

13. Motor vehicle substantially as herein described with reference to the accompanying drawings.

SP2129.P3 19/03/98