GB2329442A

GB2329442A - Timed controlled engaged state of an automatic clutch

Info

Publication number: GB2329442A
Application number: GB9811827A
Authority: GB
Inventors: Michael Salecker; Martin Zimmermann; Rolf Mack; Gebhard Michenfelder
Original assignee: Robert Bosch GmbH; LuK Getriebe Systeme GmbH
Current assignee: Robert Bosch GmbH; LuK Getriebe Systeme GmbH
Priority date: 1997-06-04
Filing date: 1998-06-03
Publication date: 1999-03-24
Anticipated expiration: 2018-06-03
Also published as: ITMI981237A1; ES2155743B1; NO982429D0; JPH10331870A; DE19824772A1; FR2764249A1; GB9811827D0; BR9801768A; NO982429L; GB2329442B; KR19990006601A; KR100539839B1; ES2155743A1; FR2764249B1; DE19824772B4

Abstract

An automatic clutch 3 is controlled by a control unit 13 receiving signals from various sensors, eg clutch position sensor 14, gear position sensors 19a, 19b throttle sensor 31, brake sensor 41 etc. If, for example, the control unit 13 receives no new data or implausible data from the clutch position sensor 14, the control unit 13 recognises it as a fault or failure and enters an emergency operating control in which the clutch 3 is controlled in a time dependent manner, eg by pulse-width-modulation etc, wherein engagement and/or disengagement of the clutch 3 takes place at a lower drive/current output than in a normal operation. An electric motor 12 is operated by the current so as to produce the required drive which operates, via gearing, a hydraulic master cylinder 11 coupled to a slave cylinder 10 that operates the clutch 3. The clutch 3 may be a dry friction clutch, multi-plate clutch, magnetic powder clutch or a bridging clutch.

Description

2329442 1 DEVICE FOR THE CONTROL OF AN ENGAGED STATE The invention relates

to a device for the control or emergency operating control of an engaged state of an automatically operable clutch in the drive train of a motor vehicle with an engine and a gearbox, with an operating unit controllable by a control unit with a drive, for operating such as engaging and/or disengaging the clutch.

Devices of this kind are known from DE OS 40 11 850. Motor vehicles with devices of this kind have as a rule an internal combustion engine and an automatically controlled clutch for transferring the drive torque. In order to control the torque transferable by the clutch a position regulation or control is carried out by means of the sensor signal of a sensor which detects the engaged state of the clutch. This sensor can be a path sensor.

If for example the sensor for detecting the engaged state is defective or damaged then a position regulation can no longer be carried out for a rapid change or for a change of the torque transferable by the clutch. The engaged state which is to be set can thus no longer be implemented in the manner intended.

An object of the invention is to provide a device of the above kind which in the event of a temporary or complete breakdown of the sensor unit for detecting the engaged state guarantees a reliable control or regulation of the clutch engagement state. A further object of the invention is that despite a failure of such a sensor the comfort of the automated clutch system can be substantially maintained.

This is achieved with a device according to the invention in that the drive of the operating unit is operated timecontrolled. This time-control provides that the drive is controlled in dependence on time so that the drive output is controlled as a function of time, that a certain predefinable engaged state is reached which is achieved by a timedependent current supply from a for example electric motor. Instead of using a position regulation a predetermined ideal position is thereby reached through the deliberate time-controlled drive output. If for example the engine is supplied with current for a shorter time then a smaller path is covered during engagement or disengagement and if the engine is supplied with current for a longer time then a longer path is travelled during engagement or disengagement. The longer or shorter current supply is only used as an example here for a timedependent control or regulation of the power of the drive unit.

With a device for the control or emergency operating 20 control of an engaged state of an automatically operable clutch in the drive train of a motor vehicle with an engine and a gearbox, with an operating unit controllable by a control unit with a drive, for operating such as engaging and/or disengaging the clutch it is further advantageous if the drive of the operating unit is operated controlled in time so that with an engagement process the drive is operated with a lower output than with a disengagement process.

According to a further idea according to the invention, with a device for the control or emergency operating control of an engaged state of an automatically operable clutch in the drive train of a motor vehicle with an engine and a gearbox, with an operating unit controllable by a control unit with a drive, for operating such as engaging and/or disengaging the clutch it is expedient if the drive of the operating unit is operated controlled in time wherein with an engagement process the drive is operated with a lower output than maximum output. Through the reduction in the drive output it is possible to reach a substantially more accurate positioning of the engaged state if a time-controlled operation of the clutch is carried out. A smoother driving off or coupling during a gear change can thereby be achieved.

Furthermore with a device for the control or emergency operating control of an engaged state of an automatically operable clutch in the drive train of a motor vehicle with an engine and a gearbox, with an operating unit controllable by a control unit with a drive, for operating such as engaging and/or disengaging the clutch it is advantageous if the drive of the operating unit is operated controlled in time so that with an engagement or disengagement process the drive in a first time phase is operated at maximum output and in a further time phase at a lower output.

It is particularly advantageous if the device has a sensor for detecting the engaged state of the clutch. By means of this sensor it is possible to monitor the timecontrolled drive output in order to reach a desired engagement position.

It is likewise advantageous if the device has a sensor for detecting the engaged state of the clutch and the engaged state is regulated or controlled by means of a position regulator or a position control with an orderly function of the sensor. The time- controlled control or regulation of the drive output can be carried out for example in the event of a f ailure of the sensor.

With an advantageous embodiment of the invention the drive - 4 is formed as an electric motor. With a further embodiment according to the invention the drive can have a hydraulic unit with electrically controllable valves. It can likewise be expedient if the drive has an electric magnet.

Furthermore it is particularly expedient if to control the output of the drive the drive is operated with a timecontrolled current supply wherein with a lower current supply to the drive the output of the drive is less. By lower current supply can also be meant a lower scanning ratio with a pulse-width-modulated control. An amplitudereduced signal can also be included 'here. Furthermore it is expedient if the current supply of the drive takes place time-controlled such as time-variable, amplitudemodulated or pulse width modulated.

It is advantageous if the current supply or output of the drive with an engagement process or with a disengagement process in at least one of the time phases is 20 to 80%, more particularly 30 to 60% and advantageously 40 to 50% of the maximum current or output.

In a further embodiment of the invention it is expedient according to a further idea according to the invention if the control unit determines the actual coupling engagement state by means of the data of the time-controlled output, such as current supply of the drive and of the engaged state prior to an operation of the clutch and the time of the controlled output.

It is likewise expedient if the control unit selects the output, such as current supply of the drive in dependence on the actual engaged state or on the engaged state prior to operation of the clutch.

It is further expedient if the control unit controls, such as varies the output of the drive as a function of the engaged state actually determined.

According to a further idea according to the invention it is advantageous if with an engagement process of the clutch the drive is controlled with reduced output until the engaged state determined by the control unit corresponds to the engaged position wherein in this engaged position the slip of the clutch is detected and with the presence of a slip the clutch is further engaged until the detected slip has substantially disappeared.

According to a further idea according to the invention it is advantageous if with a failure or defect or with an implausible sensor signal of the sensor for detection of the engaged state of the clutch a change over into an emergency operating control is undertaken. This detection of a defect or failure or fault can be carried out for example where the signal of the sensor lies outside of an area which is normally adopted when the sensor operates properly. If the sensor signal is outside of this area it can be assumed that the sensor indicates a value which does not appear suitable. If the signal completely fails for example in the event of a defect in the supply line or rises to an infinite value then a failure can be detected.

The invention will now be explained with reference to the examples shown in the drawings in which:

Figure 1 is a diagrammatic illustration of a vehicle; Figure 2 is a block circuit diagram; Figure 2a is a block circuit diagram; Figure 3 shows a device for operating a clutch.

Figure 1 shows diagrammatically a motor vehicle 1 with an engine 2, such as an internal combustion engine.

6 Furthermore a clutch 3 and gearbox 4 are contained in drive train of the motor vehicle. In this embodiment the clutch is mounted in the force flow between engine and gearbox wherein a drive moment of the engine is transferred through the clutch to the gearbox and from the gearbox 4 on the output side to an output shaf t 5 and to an axis 6 and wheels 6a.

Figure 1 shows furthermore a device for the control or regulation of the engaged state of a clutch such asin particular an automated clutch. Basically the engagement position of the clutch between two end positions is considered the engaged state. In one end position there is substantially no torque transferred by the clutch and in the other end position maximum torque is transferred by the clutch. The engaged state can also be characterised by the torque transferable by the clutch. In normal strategy it can be advantageous if the control of the clutch takes place controlled by example a position control is emergency strategy in the event of sensor a time-controlled clutch control is carried out an event and thus f or carried out. In an advantageously instead of the control.

a failure of a position event-controlled clutch The device can in a further embodiment of the invention also be operated by means of an emergency operating control in the event of a failure of a sensor or another component part of the automated clutch wherein the control unit of the device detects the defect or failure and switches over into emergency operating control.

The clutch can be formed as a friction clutch, such as a 7 dry friction clutch, multi-plate clutch, magnetic powder clutch or converter-bridging clutch of a torque converter. The clutch can also be a self-adjusting wear- compensating clutch. The gearbox 4 is shown as a manual shift transmission such as a step-change gearbox.

According to an idea according to the invention the gearbox can however also be an automatic shift transmission which can be shifted automatically by means of at least one actor. By automated shift transmission is meant basically 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 gearbox substantially without break in the pulling force during the shift processes and which is as a rule built up through planetary gear phases. Furthermore an infinitely adjustable gearbox can be used such as for example a cone pulley belt contact gearbox. The automatic gearbox can also be formed with torque transfer system 3, such as clutch or friction clutch on the output side.

The clutch can further be formed as a starting clutch 25 and/or turning set clutch for changing the direction of rotation and/or safety clutch with a deliberately controllable transferable torque. The clutch can be a dry friction clutch or a wet-running friction clutch which runs for example in a fluid.

The clutch 3 has a drive side 7 and an output side 8 wherein a torque is transferred from the drive side 7 to the output side 8 by a clutch disc 3a biased with force by the pressure plate 3b, the plate spring 3c and the disengagement bearing 3e as well as the flywheel 3d. The disengagement lever 20 is operated by an operating unit 90 such as actor 13b for this biasing.

The control or regulation of the engaged state of the clutch 3 is carried out by means of a control unit 13. The control unit can comprise the control electronics 13a and the operating unit 90. In another advantageous design the control unit can only comprise the control electronics 13a, the operating unit is housed in another housing. The control unit 13 can contain the control and power electronics for controlling the electric motor 12 of the actor 13b. It can thereby advantageously be reached that the system requires as a single structural space the space for the actor with electronics.

The operating unit consists substantially of a drive 12 such as electric motor wherein the electric motor 12 acts on an output element through a gearbox such as worm gear or spur wheel gear or crank gear or threaded spindle gear. This output element can be a master cylinder 11. The output element can also be a rod linkage or other connection.

The movement of the output part of the actor or operating unit such as 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 engaged position or engaged state or speed or acceleration respectively of the clutch. The engaged position or engaged state thus characterises the torque transferable by the clutch since this transferable torque is coupled through the clutch characteristic line to the engaged position or engaged state.

The master cylinder 11 is connected to the slave cylinder 10 through a pressurised medium line 9 such as a hydraulic 9 line. The output element loa of the slave cylinder is in active connection with the disengagement lever or disengagement means 20 so that a movement of the output part loa of the slave cylinder 10 causes the disengagement means 20 to likewise be moved or tilted in order to control the torque transferable by the clutch 3.

The force biasing of the pressure plate or friction linings respectively can be deliberately through the position of the disengagement means 20 such as disengagement fork or central disengagement member whereby the pressure plate can thereby be moved between two end The one positions and set and fixed anywhere inbetween end r)osition corresDonds to controlled a fully engaged clutch position and the other end position corresponds to a fully disengaged clutch position. In order to control a transferable torque which is for example less or greater than the engine moment momentarily arising a position of the pressure plate 3b can be controlled for example which lies in an intermediate area between the two end positions. The clutch can be f ixed in this position by means of the deliberate control of the disengagement means 20. However transferable clutch moments can also be controlled which lie definitely above the engine moment momentarily arising. In such a case the engine moments actually arising can be transferred whereby the torque irregularities in the drive train in the form of for example torque peaks are damped and/or insulated.

In order to govern, such as control or regulate the engaged state of the clutch sensors are also provided which monitor at least at times the relevant values of the overall system and which supply the condition values, signals and measured values which are necessary for control and which are processed by the control unit wherein a signal connection with other electronics units - 10 such as for example an engine electronics or an electronics unit of an anti-lock braking system (ABS) or anti-slip regulation (ASR) can be provided. The sensors detect for example speeds, such as wheel speeds, engine speeds, the position of the load lever, the throttle valve position, the gear position of the gearbox, a shift intent and further characteristic values which are specific to the vehicle.

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

The gearbox is formed as a step change gearbox wherein the translation stages are changed by means of a shift lever or the gearbox is operated or activated by means of this shift lever. Furthermore at least one sensor 19b is mounted on the operating lever, such as shift lever 18b of the manual shift gear to detect the shift intent and/or gear position and send same to the control unit. 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 take place in that the sensor is a force sensor which detects the force acting on the shift lever. Furthermore the sensor can also 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 unit is in signal connection at least at times with all the sensors and evaluates the sensor signals and system input values in a manner and way where 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 device as hard and/or software which evaluates the incoming signals and calculates or determines the output values from comparisons and/or functions and/or characteristic fields.

The control unit 13 advantageously has implemented a 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 as software so that by means of the incoming sensor signals it is possible to determine the torque of the drive unit 2 of the vehicle 1, the gear position of the gearbox 4 as well as the slip which prevails in the area of the clutch and also the actual operating state of the vehicle. The gear position determining unit detects from the signals of the sensors 19a, 19b the gear actually engaged. The sensors are thereby attached to the shift lever and/or to setting means inside the gearbox, such as for example a central shift shaft or selector rod, and these detect for example the position and/or the 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 recognised whether the load lever such as accelerator pedal is 12 - activated. The load lever sensor 31 detects the degree of activation of the load lever.

Figure 1 shows in addition to the accelerator pedal 30 5 such as load lever and the sensors connected therewith a brake operating element 40 for operating the operating brake or the 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 its operation. The sensor 41 is for example formed as a digital sensor such as a switch wherein this detects that the operating element is activated or is not activated. A signal device such as a brake light can be in signal connection with this sensor to signal that the brake is activated. This can take place both for the operating brake and for the parking brake. The sensor can however also be formed as an analogue sensor wherein such a sensor such as for example a potentiometer determines the degree of operation of the operating element. This sensor can also be in signal connection with a signal device.

The control unit controls or regulates the clutch engagement position or the engaged state of the clutch, thus substantially the torque transferable by the clutch, through a timecontrolled control of the drive of the operating unit. The ideal position is controlled through this time-controlled control and a thereby substantially parallel position determination, such as calculation. From the data of the engaged state at the time prior to adjustment of the engaged state and from the timecontrolled drive output it is possible to determine the relevant travel path and thus the relevant actual position or actual engaged state.

This can be the case particularly if a position sensor has 13 - failed or broken down or a signal of such a sensor has f ailed. In such a case, such as an emergency operating control of the operation of an automated clutch it is possible to change over from a position regulating process to a time-controlled process. The drive output of the drive is thereby controlled in time so that with the provision of a fixed time for the action of the drive starting from an actual position value a predeterminable position value is reached. This can also be achieved in that the pulse rate or beat rate of for example the current supply of the drive is used time-controlled.

With a time-controlled operation of the operating unit it is advantageous if the engagement process and/or the disengagement process takes place at a lower drive output or force than in a posit ion- regulated operation or in a normal operation. In the case of an engagement process and/or disengagement process it is expedient to reduce the drive power and/or current supply of the drive and it is also advantageous to carry this out during at least one time range so that the operating unit with a timecontrolled control does not move against a stop or end stop with a full power or force. If this is the case then the service life of the operating system drops considerably since the design of the component parts of the operating system is as a rule not made for such high loads and at least some individual component parts of the operating unit would be permanently damaged mechanically.

To determine the actual engagement position or engaged state the actual position is calculated based on the data of the relevant drive output in each relevant engaged position. The change in the actual position is thereby a function of the engagement position itself since the force of the clutch acting in each engaged position is substantially different.

14 - The drive output is thereby selected during an engagement and/or disengagement process as a function of the relevant engagement position.

If for example a sensor is provided for detecting the engaged state then the failure or fault of a sensor can be recognised for example in that the sensor signal has left a plausible value range. Likewise a fault of the sensor can be recognised if for a predefinable time, such as for example the length of at least two or more, such as ten, beat rates of the control (time cycles or software interrupts) or of the processor the data of the sensor are not updated or the sensor receives no new data. It is thereby assumed that the processor inputs and/or receives sensor signals in beats. If for example the beat rate is 2 ms then it is expedient if the sensor is regarded as faulty if for at least 20 ms no signals or no new signals are received. This is expedient if the sensor signal is detected every 2 ms.

If a fault in the sensor is recognised then a flag or status bit is set in a memory to show a fault exists. In this case the actual engaged position or actual engagement state is set to the last value of the last beat rate wherein at this time point the sensor should have still functioned properly. The calculated engaged state assumes for example a value in the value range from 0 to 2000 wherein these values can be selected in any way. If the fault occurs directly after switching on the vehicle ignition then the value of the engaged state can be set to 0 because it can be assumed from this that the clutch is closed in the parking lock position. The value range 0 to 2000 can correspond to a path of the clutch operating element of 0 to 20 mm.

- is During engagement or disengagement different requirements can arise simultaneously wherein the disengagement of the clutch has a higher priority than the engagement of the clutch.

If one of the following conditions example:

Shift intent of the driver through moving the shift lever is fulfilled for 0 Neutral area selected in gearbox Stopping such as gear speed < idling speed + WERT and operating brake activated Danger of stalling, such as engine speed < 500 1/min then the operating unit is controlled in the "disengagement" direction of the clutch, that is the drive of the operating unit is controlled in the direction of disengaging the clutch, such as is for example supplied with current. If the clutch is engaged for example so that the determined value of the engaged position assumes a value in the value range between 0 and 1200 then the drive is operated with full power. If the value of the engaged position is in the value range between 1200 and 2000 then the drive is operated with reduced output, for example at 50% of maximum output. The division of the entire value range into at least two areas can also be carried out with a different split. With the value 2000 the output is reduced to nil.

The clutch is engaged if for example one of the following conditions exists:

Ignition of engine off and speed < 2001/min (implementation of a parking lock for example with the vehicle switched off) 0 Gear speed > idling speed.

16 - In the value range 0 to 100 the drive output is controlled for example to 60% of the maximum drive output or the current to the engine is controlled to 60% of the maximum current. This advantageously leads to a safe release of the drive from the rest position and overcomes the adhesive friction in the rest position.

The current supply or drive output is reduced to 10% basically at the value 100. This can advantageously produce a slow pass through the bite point. This advantageously causes a smooth start for the vehicle or a smooth recoupling after a gear change.

In the value range from 100 to 1600 the drive output or current supply is raised linearly or non-linearly from 10% to 20%. This is advantageous if different disengagement forces of the clutch exist or if the clutch characteristic line changes as a result of wear on the clutch.

In the value range from 1600 to 2000 the current supply or drive output is raised from 20% to about 40% linearly or in another functional way. It is thereby advantageously reached that the clutch can also close completely.

During the engagement process or during the disengagement process the actual engaged position is constantly updated and determined or calculated again.

If in the case of an engagement process the clutch is closed after the calculated value of the engaged position and slip still occurs in the area of the clutch then the clutch is closed further until the slip disappears. The slip is calculated from the clutch engagement speed and 35 the clutch output speed.

17 - Figure 2 shows a block circuit diagram 100 for illustrating a device according to the invention and a method according to the invention. In block 101 it is asked whether the clutch is closed. The process is thereby like the routine already in an emergency running or emergency operating control mode. Determining whether the clutch is closed can take place on the basis of vehicle operating data wherein in block 102 the question is answered yes and in block 103 is answered no. If the question of block 101 is answered yes then in block 104 and the following blocks an engagement of the clutch is carried out. If the question of block 101 is answered no then in block 112 and the following blocks a disengagement of the clutch takes place.

Furthermore counters Zahler - 1 and Zahler-2 are used and described which are used as time counters which during operation of the drive of theoperating unit can calculate the duration of the drive or can determine therefrom the position or engaged state. The one counter Zahler - 1 is used as a time counter for full current supply and the counter Zahler-2 is used as the counter for partial current supply. It is thereby possible to determine the necessary time of full current supply and/or partial current supply respectively for a partial or full power drive.

In block 104 it is checked or questioned whether the counter Zahler 1 assumes a value greater than nil (> 0).

If this is the case since the block 106 answers this question with a positive, then in block 107 the counter Zahler 1 is reduced by an increment (by the value 1) to the value Zahler-1 = Zahler-1 - 1. Then at block 111 an engagement of the clutch takes place with a partial current supply of the operating unit or actor motor. if the counter Zahler-1 at block 104 is not greater than nil - 18 then in block 108 the slip, thus the speed difference between the gear input speed and engine speed is detected. If the slip is greater than 50 1/min, see block 109, then with a partial current supply in block 111 the clutch is engaged. If the slip is not greater than the predefinable value of 50 1/min see block 110, then the clutch is retained in its actual position or the clutch is disengaged accordingly.

If the clutch is to be opened after block 103, then in block 112 it is asked whether the counter Zahler 1 assumes a value less than 200, as for example with a substantially mean value or with a partially engaged clutch. If this is the case, then the counter Zahler 1 is incremented by the value 20 to Zahler - 1 + 20. The second counter Zahler-2 is set to the value nil or left there.

In block 121 the clutch is disengaged with a full current supply.

If the counter in block 112 is not less than 200, see block 114, wherein this can be a boundary value, which differs by a predeterminable amount from the end value, it is asked in block 116 whether the counter Zahler 2 is decremented by a value 1, that is Zahler - 2 = Zahler-2 - 1. Then in block 120 the clutch is disengaged with partial current supply.

Figure 2a shows a further embodiment of a use according to the invention of a device according to the invention or a process according to the invention. Figure 2a shows a block circuit diagram 200. In block 201 a sensor fault is detected of a sensor which detects an engaged state of the clutch. It is asked whether this fault has occurred for a first time or whether this fault has already occurred previously. If this fault has appeared for the first time then in block 202 a counter Offnen counter is set to the 19 - value of the clutch position "kist" at the time ofthe preceding beat of the processor. Thus if Offnen-counter = kist (t-At), At is in the embodiment of Figure 2a 10 2 MS. It then proceeds to block 203. In block 203 it is asked whether the ignition of the vehicle is switched on for example by means of an ignition key and thus the control unit and other vehicle assemblies are activated.

If this is not the case, the clutch is closed. In block 204 a counter Schliess - counter is questioned. If the Schliess counter is not less than 200 then the current for the actor is set to nil, see 205, and the procedure is ended at 206. If the Schliess counter is less than 200m, in block 204, then in block 207 it is asked whether a drive release exists, that is for example the idling switch is + 0 and thus the accelerator pedal is activated and the engine speed is greater than a predefinable value for for example 1500 1/min and the gradient of the engine speed is greater than nil or whether the gear input speed is greater than the engine idling speed or whether the ignition of the vehicle is switched of and the engine speed is less than a predefinable value of for example 200 1/min. If this is not the case then it proceeds to block 205.

If this is the case then in block 208 a memory or a flag, namely a Flag_Schliessen is set to one so that the clutch is to be closed. The counter Scliessen counter is raised by the value 1 and the setting operating direction is set to the direction "Close/Schliessen".

In block 209 the current i for supplying current to the drive motor is set to a function of the counter Schliess-counter. That is, the relevant current i is selected variable as a function of the counter, so that for example at the beginning a rapid closing process can take place and then at the end of the closing process a slower closing can take place.

In block 210 a counter Offnen counter is set as the function of the counter Offnen counter itself and as a function of the current i so that the counter assumes a value representing the actual position.

If in block 203 the ignition of the vehicle is switched on then in block 211 it is asked whether the brake, such as the operating brake or the parking brake is activated and the gearbox speed is less than the engine idling speed + 200 1/min or whether the engine speed is less than a stall threshold, such as for example 500 1/min or whether the neutral gear is engaged in the gearbox or whether a shift lever movement of the gear shift lever is detected by a sensor as a shift intent. If this is not the case then it proceeds at 204. If this is the case the clutch is opened or disengaged.

In block 212 it is asked whether a memory or flag assumes the value Flag Schliessen = 1 and whether a counter Offnen-counter is greater than a predefinable value 959. If this is not the case, then it proceeds at block 214. If this is the case, then at block 213 the counter Offnen- counter is set to the value 959. This is advantageous so that with a change of direction of the operating actor movement no sticking takes place.

In block 214 the memory or flag Flag_Schliessen is set to nil, the counter Offnen - counter is set to nil andthe displacement direction of the operating unit is set to Open/Offnen".

In block 215 it is asked whether the counter Offnen counter is < 2000. This position (Offnen-counter 21 < 2000) can assume or represent for example an end position. If this is not the case, then at 220 the current for supplying the actor or operating unit is set to nil since the clutch is already disengaged. In block 216 the counter is raised by a predefinable value of for example 80. In block 217 it is asked whether the counter Offnen-counter is less than 1200. If this is not the case, then at 219 the drive is operated with a current supply of about 50% of the maximum current supply. if this is the case in block 217 then in block 218 the drive is operated at maximum supply.

Figure 3 shows an operating unit, such as an actor 300 which has a drive, such as electric motor 302, and a housing 301. The electric motor drives a worm through its motor output shaft. This worm meshes with a worm wheel 303. A push rod 304 is attached rotatable on the worm gear wheel 304 and is in active connection with the piston 305 of a hydraulic master cylinder 306. The hydraulic master cylinder is in connection with a salve cylinder 307 through a hydraulic path 308 to operate the clutch.

Furthermore an energy accumulator such as a spring 311 is provided to assist the electric motor.

The sensor 310 detects the position or angular position of the worm gearwheel 3030 and thus the disengagement position of the clutch since these are coupled together through the connection 304, 305, 308, 307.

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 in the description and/or drawings.

- 22 References used in the sub-claims refer to further designs of the subject of the main claim through the features of each relevant sub-claim; 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.

Claims

1. Device for the control or emergency operating control of an engaged state of an automatically operable clutch in the drive train of a motor vehicle with a motor and a gearbox, with an operating unit controllable by a control unit with a drive, for operating, such as engaging and/or disengaging the clutch, characterised by its special configuration and method of operation according to the present application documents.

2. Device for the control or emergency operating control of an engaged state of an automatically operable clutch in the drive train of a motor vehicle with an engine and a gearbox, with an operating unit controllable by a control unit with a drive, for operating such as engaging and/or disengaging the clutch, characterised in that the drive of the operating unit is operated controlled by time.

3. Device for the control or emergency operating control of an engaged state of an automatically operable clutch in the drive train of a motor vehicle with an engine and a gearbox, with an operating unit controllable by a control unit with a drive, for operating such as engaging and/or disengaging the clutch characterised in that the drive of the operating unit is operated time-controlled so that during an engagement process the drive is operated with a lower output than during a disengagement process.

4. Device for the control or emergency operating control of an engaged state of an automatically operable clutch in the drive train of a motor vehicle with an engine and a gearbox, with an operating unit controllable by a control unit with a drive, for operating such as engaging and/or disengaging the clutch characterised in that the drive of the operating unit is operated time-controlled so that 24 during an engagement process the drive is operated with a lower output than maximum output.

5. Device for the control or emergency operating control of an engaged state of an automatically operable clutch in the drive train of a motor vehicle with an engine and a gearbox, with an operating unit controllable by a control unit with a drive, for operating such as engaging and/or disengaging the clutch characterised in that the drive of the operating unit is operated time-controlled so that with an engagement or disengagement process the drive is operated in a first time phase at maximum power and in a further time phase at a lower power.

6. Device according to one of the characterised in that the device has detecting the engaged state of the clutch.

preceding claims a sensor for

7. Device according to one of the preceding claims, characterised in that the device has a sensor for detecting the engaged state of the clutch and the engaged state is regulated or controlled in the event of a correctly functioning sensor by means of a position regulator or a position control.

8. Device according to one of the preceding claims characterised in that with a failure or defect or with an implausible sensor signal of the sensor for detecting the engaged state of the clutch a change-over is made into an 30 emergency operating control.

9. Device according to at least one of claims 1 to 8 characterised in that the drive has an electric motor.

10. Device according to at least one of claims 1 to 8 characterised in that the drive has a hydraulic unit with electrically controllable valves.

11. Device according to at least one of claims 1 to 8 characterised in that the drive has an electro magnet.

12. Device according to one of the preceding claims characterised in that to control the power of the drive the drive is operated with a timecontrolled current wherein with a lower current in the drive the output of 10 the drive is less.

13. Device according to claim 12 characterised in that the current to the drive takes place time-controlled such as time-variable, amplitudemodulated or pulse-width modulated.

14. Device according to one of the preceding claims characterised in that the current to or output of the drive with an engagement process or with a disengagement process in at least one of the time phases is 20 to 80%, more particularly 30 to 60% and advantageously 40 to 50% of the maximum current or output.

15. Device more particularly according to one of the preceding claims characterised in that the control unit determines the actual clutch engaged state by means of the data of the time-controlled output, such as current or ideal current of the drive and of the engaged state prior to an operation of the clutch and the time of the 30 controlled output.

16. Device according to claim 15 characterised in that the control unit selects the output, such as current, of the drive in dependence on the actual engaged state or the engaged state prior to an operation of the clutch.

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17. Device according to claim 16 characterised in that the control unit controls, such as varies the output of the drive as a function of the engaged state actually determined.

18. Device more particularly according to one of the preceding claims characterised in that with an engagement process of the clutch the drive is controlled with reduced power until the engaged state determined by the control unit corresponds to the engaged position wherein in this engagement position the slip of the clutch is detected and with the presence of slip the clutch is further engaged until the detected slip substantially disappears.

19. Process for the control or emergency operating control of an engaged state of an automatically operable clutch in the drive train of a motor vehicle with an engine and a gearbox, with an operating unit controllable by a control unit with a drive, for operating such as engaging and/or disengaging the clutch characterised in that the drive of the operating unit is operated controlled by time.

20. Device for the control of an engaged state of a clutch substantially as herein described with reference to the accompanying drawings.