GB2210127A

GB2210127A - Clutch control for a motor vehicle

Info

Publication number: GB2210127A
Application number: GB8814784A
Authority: GB
Inventors: Rudy Tellert; Franz Nagler
Original assignee: Sachs Systemtechnik GmbH
Current assignee: Sachs Systemtechnik GmbH
Priority date: 1984-10-20
Filing date: 1985-10-18
Publication date: 1989-06-01
Also published as: FR2572032B1; DE3438594C2; GB8814784D0; GB2210126A; GB2165914B; GB8525783D0; GB2210127B; GB2210126B; FR2572032A1; GB8814783D0; GB2165914A; DE3438594A1

Abstract

A friction clutch (3) has a clutch releaser (9) the position of which fixes the torque transmittable by the friction clutch (3). A setting drive (15, 17) positions the clutch releaser (9). A position indicator (23) controls the setting drive (15, 17) and is coupled with a clutch pedal (21). The position indicator (23) generates an electric control signal representing the position of the clutch pedal (21), and an electric adaptor device (49) enforces a predetermined non-linear relationship between the position of the clutch pedal (21) and the control signal. The setting drive (15, 17) comprises an electric position regulator circuit (17) which adjusts the position of the clutch releaser (9), through an electrically controllable setting member (15), to a position fixed by the control signal. <IMAGE>

Description

Chutch equipment for a mottr vehicle The invention relates to clutch equipment for a moter vehicle according to the opering statement of Patent Claim 1.

In @erman Patent Application P 33 30 332 which is not a prior publication, clutch equipment for a motor vehicle is described in which for the demping of torisonal vibrations and for the reduction of undesired noises bv Leans ol a slip-regulator circuit in dependence upon the engine rotation rate and the gea rinput rotation rate, the position of the clutch.

releaser is controlled so that even in the engaged condition the clutch works with a predetermined slip.

It is the problem o the invention t design clutch equipment in which a slip-regulator circuit ensures a predetermined slip or a predetermined rotation rate difference in dependence upon the engine rotation rate and the gear input rotation rate, in such a way that the clutch equipment satisfies the operational conditIons occurring in drivIng operation of the rotor vehicle, and at te are tine rotary vibrations and operating noises are effectively reduced.

Within the scope of the invention this probler is solved in that an averaging circuit generates es z rear, value signal corresponding to the mean value in time of the rotation rate difference between the detected englne rotation rate and the detected gear input rotation rate and related to a time interval of constant duration, and in that the slip-regulator @ircuit controls the setting drive in dependence upon the mean value signal.

The invention is based upon the fact that torsiona vibrations and operating noises of the clutch and gear are caused by the irregular rotation of the engine. During the working stroke of each cylinder the engine is heavily accelerated during an angle of rotation which is small incomparison with a full revolution of the orankshaft, while until the working stroke o toe next cylinder it rotates with h subs tan- tially uniform angular speed. These surges cause rotational vibrations and gear noises.The averaging circuit used in accordance with the invention generates an error sisal i relation to a base value which represents the substantialy constant angular speed be@ween the working strokes of the cylinders.

This error signal controls the setting drive of the clutch releaser and permits a uniform, overshot-free regulation of the slip. Advantages are obtained especially under operational conditions in which the clutch is already transmitting the working torque.

This results in an operational behaviour inwhich the clutch slips only during the working strokes of the cylinders while between te working strokes it sub- stantialy does not slip. In this manner the thermal stressing of the clutch can be kept low.

The actuating device can oe a conventional clutch pedal which positions the clutch releaser either through a separate setting member or trough the setting member of the slip regulator circuit. The arrangement can be made so that the clutch releaser is actuated conventionally through hydraulic master and slave cylinders directly from the clutch pedal, while the setting member merely ensure an additional positioning of the clutch releaser in relation to the slave cylinder on te releaser sie Of te hyiraulic system.In palce of a clutch penal however there may equally be an automatic clutch acutation device which controls te settIng member allocated to te clutch pedal.

In a preferred form of embodiment the setting drive is a positional servo-drive which sets the position of the clutch releaser to a position fixed by an ideal position signal. The servo-drive is expediently controlled both through the slip regulator circuit and through the actuating device, for example the clutch pedal. The ideal position signals generated by te slip regulator circuit or the actuating device are standardised in mutually corresponding manner so that the servc-drive is controllable alternately either through the actuating device, that is through the clutch pedal, or through the slip regulator circuit.

Kore especially in this manner it is possible to avcid undesired variations ofposition of the clutch releaser in gear changing. The slip regulator circuit is here switched cf when the sll et on the clutch pedal is greater than the slip to be maintained by the slip regulator circuit at a predetermined value.

In a preferred for@ of enbodiment the averaging circuit comprises tw@ signa@ patks for the signals which represent t@e r@tation rate difference or are used for the for@@@@ of the rotation rate difference The one signal pat@ @@@ains an integrator which carries out the averaging, The other signal path has an amplification of 1 an transfers the signal representative of tre rotation rate difference substantially unchanged to the cutput of the averaging circuit The time constants of the two signal paths are greatly different. While the signal path ocntaining the integrator has a high time constant, so that its output signal follows cnly slow variations of the rotation rate difference signal, the other signal path has a ic-: tie constant so that rapid variations of te rotation rate difference sIgnal appear @ith the ampli- ficatior 1 at the output of the averaging circuit. If the averaging circuit is realised by an operational amplifier the to signal paths are reajised ty the different time consants of the two inputs.

Estecially in the case of averaging circuits assembled from active components, saturation effects cat occur within the slip regulator circuit which delay the response of the slip regulator circuit in te case of a variation of its input signals. in order to prevent this, in a preferred form of embodiment a limiter circuit is connected to the Integrator and li-its the output signals of the integrator to its oportionality range.The limiter circuit extediently not only ' imits the regulation range out also ensures a pre-setting of the integrator during those operating phases in which the servo-drive is controlled from the actuating device. While the actuating device is effective, the slip regulator circuit is made ineffective, as already mentioned aabove. Konetheless the integrator follows the signals representative of the engine rotation nate or gear input rotation rate, in order In the transition of the guidance of the servo-drive from the actuating device, to be able to connect the slip regulator circuit as delay-freely and signal-jump-frelly as possible.

Since this transition of the guidance of the servo-drive can involve a sudoen variation of the position of the clutch releaser determined by the actuating device, that is the clutch pedal, and thus a sudden variation of the slip, the limiter circuit is preferably controllable in dependence upon the position of the clutch pedal a@the position of an accelerator @edal in such a manner that the integrator can be made fast to predetermined values of its cutput signal in dependence up@n the position of the clutch pedal and/or of the accelerator pedal. The output signal of the integrator can thus be set to values which reduce the slip error to be expected on a variation of these pedal pcsitions.

In a preferr@d form of embodiment the slip reg. lator circuit comprises a slip value control circuit which controls the ideal slip value, to be maintained by the slip regulator circuit, in dependence upon the engine rotation rate. In this way it cs. be ensured that the friction clutch wcrks with predetermined slip only when this is necess@ry by reason fo the design of the engine-gear line of the vehicle, More especially mechanical resonance points of the engine gear line can be damped by resonance-type raising of the slip in the region of the resonance @equency.

The slip value control circuit is expediently designed so that the slip decreases with inoreasing engine rotation rate and more especially has dropped to zero at a rotation rate at which the clutch is ordinarily alreadg engaged. Apart from the already mentioned resonance rises the slip is expediently reduced to zero at a rotation rate between 2,000 and 2,600 revolut@cns per minute. This rotation rate range lies as a rule belcw the rotation rate at which the maximum engine torque results.

When the friction cluton is engaged, the engine is idling end the gear is situated in the neutral position, by reason of the non-uniformity of rotati@ of the engine what are called clutch or gear rattles can occur. The rattling can be prevented if with the gear in toe neutral gear position the clutch is disengaged independently of the clutch actuating device, that is the real. The neutral gear position could be detected with a sensor on the gear, which however requires relatively high constr@ctional expense.

A second aspect of the invention, which can also be used in clutch equipment other than that already explained, concerns the suppression of the atove explained ialing rattle, without the requirement to wse a senscr responding to the neutral position of the ear.

For this prpose a release control is provided wsich can release the clutch indeyendently of the clutch act@ating device through a setting drive, possibly the setting drive of the clutch actuating device. The release control releases the cluich when the travelling speed detected by reans of a speed indicator lies in the region of a pedestrian walking speed or the vehiele is stationary, if at the same time the gear rotation rate indicator detecting the gear Input rotation rate ascertaIns a gear input rotation rate which is greater than a predetermined rotation rate lower than the idling rotation rate of the éngine and if at the same time the clutch actuating device delivers a signal which, without the release control, would control the clutch into the engagement position. IT these three conditions are present the clutch is released contrarily to the engagement condition of the cluth actuating device. The gear input rotation rate minitored in tis connection is rade so low tat with the clutch engaged under normal morking conditions it cannot occur in any of the rations of the gear without stalling the engine.A vehicle speed of less ran 3 kph and a gear input rotation rate c ore ran 300 rpn have proved suitable values for the clutch disengagement conditione The release control system expediently comprises a memory which is est when the release condition is present and is cleared again through the clutch actua ting device when this for its part generates an ideal position signal releasIng the clutch. If cr exatie the clutch pedal is oved Into the disengagement position the guidance of the setting memter transfers from the release control again to the clutch acutating device, since the -emory is cleared.

A further aspect of the invention, which is likcwisc also of importance in other clutch equipzent of motor vehicles, concerns the clutch actuation device as such. friction clutches for high engine orques require strong clutch springe which in turn necessitate high pedal forces in the release of the cluich. n order to keep the pedal forces compara- tively low, mechanical lever step-up transmissions or hydraulic step-up systems are utilised in the pedal force path. The reduction of the pedal force is however at the cost of the pedal travel which is prolonged.Therefore it is a further problem of the inventIon to indicate a clutch equipment for a motor vehicle in which te pedal travel can be dimensioned in a constructively simple manner surstantially independently of the actuating force necessary on the clutch release.

This can be brought about in a simple manner in that the clutch releaser is driven through a setting drive positionable by means of an electrio position regulator circuit, tce ideal value information of which is received from a rosition indicator detecting the position of the cluton peéal.An elactric adaptor device with a pre-determined non-linear relationship varies the relationsnip between the clutch pedal position and the ideal value information, so tat the sliding range of te clutch pedal, essential for the actuation of the clatch, can be especially stretched compared with conventional clutches and displaced in relation to the rest position of the clutch pedal0 In clütck position indicators which are formed as potentiomenters the adaptor device can te realised in the form of a non-lincar resiatance characteristic of the potentiometer. The adaptor device can however also be formed as an additional non-linear circuit, for example as diode-resistance network, connected between position indicator and the position regulator xamples of embodiment of the invention are to be explained in greater detail below by reference to drawings, wherein :: FIGURE 1 shows a diegrammatic representation of clutch equipment of a motor vehicle in wïch the friction clutch can be loaded, even In the case o operational torque transzission, with a predetermined slip, for the reduction of irregularities of rotation and noises ; FIGURE 2 shows diagrams of the slip 8 in dopendence upon the engine rotation rate nm ; FIGURE 3 shows a block cirouit diagram of a clutch control cirouit usable in the clutch equipment according to Figare 1 ; FIGURE 4 shows a programme progress plan der a control logie of the oircuit of Figure 3 ;; FIGURE 5 shows a diegram showing the mean torque Mk transmittable by the clutch in dependence upen a tension USoll determining the clutch position., for th-a explanation of a limiter circuit limiting the cutput signal of an integrator in Figure 3; FIGURE 6 shows a circuit diagram of the integrator and cf the liziter circuit according to Figure 3;; FIGURE 7 shows diegrams which show the actual position of the clutch releaser in dependence ccn the pedal travel, for the explanation o z pedal travel adaptor device of the circuit according to Figure 1, an FIGURE 8 shows z circuit diagram ol the edal travel adaptor device.

Figure 1 snows an internal combustion engine 1 of a motor vehicle which is coupled through a conventional friction disc clutch 3 with a manually changeahle gear 5. An accelerator pedal 7 controls te poer of the internal combustion engine 1 in p manner not further illustrated.The clutch 3 has a releaser 9 which is movable hydraulically by means of a slave cylinder 1'3 connected to a mester cylinder 11, between an engagement position completely engagin the clutch 3 and a disengagement position completely disengaging the clutch. The master cylinder 11 and thus the clutch releaser 9 are positioned by an electric setting member 15 which is connected thrcugh a servoregulator oirouit 37 to a clutch contral system 19.

The clutch control system 19 responds to position signals of a position indicator 23 mechanically coupled with a clutch pedal 21, and delivers ideal position signals to the servo-rogulator circuit 17 which sets the setting member 15 to a position fixed by the clutch pedal 21. To the setting member 15 for its part there is coupled a position indicator 25 which delivers actual position signals, corresponding to the actual position of te clutch releaser 9, to the servc- regulator circuit 17.

one clutch control system 19 comprises a slip regulator circuit which responds to an angina rotation rate signal, generated by Leans o an engine rotation rate indicator 27 and proportional to the totentary nine rotation rate or angular speed, and to a er input rotation rate signal generated by meane of a gear rotation rate indicator 29 and proportionel to the momentary gear Input rotation rate or angular speed, and sets the settIng member 15 to a predetermined slip between engine rotation rate and gear input rotation rate. The clutch control system 19 further responds to 2 speed signal, corresponding to the speed of travel of the vehicle, of a speed indicator represented at 31 and detecting for example the gear cutput rotation rate, also a logic control signal generated by means of a switch 33 possibly in the form of a threshold value switch on deflection of the accelerator pedal 7 out of its rest position.

The slip regulator circuit incresses the slip of the clutch 3, that is the difference between the engine rotation rate and the gear input rotation rate, independently of the actuation of the clutch pedal 21 to a predetermined slip value when the slip of the clutch determined by the position of the clutch pedal 21 Is lass than the value predetermined by the slip regulator circuit, This slip, compelled even in the case of torque-transmitting operation of the clutch, reduces the torsional vibnations and noises o the clutch 3 and the gear 5 caused b irregularities of rotation of the internal combustion engine 1, The slip regulator circuit varies the predetermined slip value S in dependence ucn the engine rotation rate not, as represented in Figure 2. At low rotation rates the degree of non-uniformity is great and correspondingly the predetermined slip S is great. The dip S drops with inoreasing engine rotation mate to zero, the slip being reduced to zero for a rotation rate at which the clutch 3 is already engaged in norzel driving operation.Figure 2 shows at 35 a typical slip - engine rotation rate characteristic ourve of the slip reguletor circuit which has a slip of about 10' in the case of rotation rates in the range of the idling rotation rate of the engine and reaches the value zero at a rotation rate of ahout 2,200 revolutions par minute. In many motor vehicles mechanical resonences cocur in the drive lire which considerably inerease the degree of non-unifonmity and the noise goneration at the resonence franquency. The slip c@aracteristio of the slip regulator circuit, ae represented at 37 for a drive line resonance lying at about 3,000 rpm., cam greatly increase the slip in the region of this resonance ani thus ensure a reduction of the non-uniformity and noise generation.On the other hand the drive line zay already be so well damped in s@ecific engine rotation rate ranges by reason of anti-resonance phenomena that the slip of the clutch is superflucus in this range. Figure 2 shows a slip characteristic 39 entered in chain lines in which the slip is reduced to zero in a rotation rate range 41 and initially rises with increasing rotanion rate before it drops away to zero again.

in practice slip values related to toe engine rotation rate, of a maximum of about 10@ in the region of the idling rotation rate and a maximum 5% at about 1,500 rpm, have proved adequate.

Figure. 3 shows detalils of the clutch control system 19 which, as already mentioned, delivers ideal position signals to tre servo-regulator circuit 17 and the setting member 15 formed as electric motor connected thereto. the position indicator 25 is formed as a potentiometer coupled with the electric motor ; the position indicator 23 is lizewise a potentiometer connected to a voltage source and coupled with the clutch pedal. The serve-regulator cirauit 17 receives the ideal position signals through an electrenic, controllabie swit@@@ @3 whicn is controlled by a control logie @3 explaired in greager detail below.

The eontrol logie @5 responds to the actuation of the clutch pedal and switones the control switch @3 on actuation of the clutch pedal into a switch position 47 in wsich the servo-regulator circuit 27 is connected through a pedal travel adaptor circuit 49 with the position in@icator 23 of the clutch pedal and c@ntrols the setting member 15 and thus the position of the clutch releaser in dependence up@n the position of the clutch pedal.

por the rogulation of the clutch slip an integrator 51 la previded the output 53 of which is connected to the control switch 43 and switched to effectiveness through the control logic 45 in a switch position 55 corrosponding to the slip enaraceristic as repreeented in Figure 2. in the switch position 55 the servo regulator circuit 17 is controlled exclusively ty ideal position signals of the integrator 51 while the pedal-dependently generated ideal position signals are switched off.

The integrator 51 comprises a sum-end-difference amplifier 57 with bigh idling amplification of which the output forming the integrator cutput 53 is connected through a capacitor 58 with the inverting input.

The inverting input is connected through a slIp parameter adjusting circuit 61 to the cuput of a frequenoy/voltage converter 63 which receives pulse signals of the gear input rotation rate indicator 29 at ist input 65. The frequency of this pulse signel is prsportional to the gear inqut rotation rate.

The engine rotation rate indicator 27 is contected to an input 67 of a requency/voltege converter 69.

The frequency/voltage converter 69 gives off at the non-inverting input of the eum-and-difference amplifier 57 a voltage which is proportionsl to the frequency of a pulse sequence delivered ty the engine rotation rate emitter 27. The integrator 51 thus in time dependence integrates a signal corresponding to the difference of the engine rotation rate signal and the gear input rotation rate signal and thus to the momentary slip of the clutch.

In accordance with the desined slip characteristics the slip regulation shculd te effective only under predetermined operational conditions of the vebicle. Por this purycse by means of an AND-gate 71 a logic slip control signal is generated when the engine rotation rate is greater than a predetermined rotation rate value nml and at the same time the gear input rotation rate is lower than a predeter- mined rotation rate ngl.The AND-gate 71 is for this purpose connected through a threshold value stage 73 responding to engine rotation rate signals for rotation rates greater than nml to te frequency/ voltage converter 69 an through a @breshold value stage 75 responding to gear input rotation rate signals for rctation rates below ngl to the frequency/ voltage converter 63.The predetermined angine rota tion rate value nml is lower than the idling rotation rate of the engine in order to be able to reduce noises and vibrations of the clutch or gear by means of the slip regulation even when the engime rotation rate dr -Ing driving to values below toe idling rotation rate.The value nml lies or example at about 300 rpm. The predetermined gear input rota tion rate value ngl lies aqbove the idling rotation rate and preferably in a rotation rate range at which the clutch is already engaged under normal driving conditions. A suitable rotation rate value lies approximately in the range of the maximum engine torque or slightly below, for example at about 2,400 rpm. At the above-mentioned rotation rate values the slip control signal ill be generated at engine rotation rate values greater than 300 rpm and gear input rotation rates below 2,400 rpm0 The control logic 45 switches the control swith 43 into the switch position 55 in dependence upon furthe parameters explained below, when the engine or gear rotation rate lies within the above-stated limits and the slip control signal is generated.

The controlling of the clutch through the clutch pedal has priority over the positioning by the slip regulator circuit. A comparator 74, which is connected with its inverting input to the pedal travel adaptor circuit 49 and with its non-inverting input to te output 53 of the Integrator 51, supplies 2 further control signal to the control logic 45 when the clutch pedal is situated in a position in which it supplies an ideal position signal for a releaser position placed clcser to the completely disengaged position thn toe slip regulator circuit.In tis case th-e control logic 25 switches the control switch 43 into the switch position 47 and the servo-regulator circuit 17 is guided by the pedal-dependently generated ideal position si She switching over of the guidance of the servo- regulator circuit 17 from the integrator 51 to the clutch pedal-dependent guide can lead to problems when by reason of the actuation of the clutch pedal great differences of rotation rate occur between engine rotation rate and gear inat rotation rate and te integrator 51 is thereby driven into saturation.

If the integrator 51 has reached the state of saturation, the esponse of the slip regulation would be delayed until the integrator 51 returns into the proportionality range by reason of a gradvally reducing rotation rate difference on its imputs. If the control switch 43 were switched into the switch position 55 while the integrator 51 is situated in the state of saturation, tis would lead to an Incorrect positioning of the clutch. In order to trevent tis a limiter circuit 77, explained in greater detail below by reference to Figure 6, is connected to the integrator 51.The limiter circuit 77 clamps the output volrage of the integrator 52 at values within the proporti2nality range of the slip regulator circuit when the slIp control signal of the AND-gate 71 fed to an input 79 is absent, that is the slip control through the control logic 45 and the control switch 43 is ineffective. Furthermore a control signal representing te deflection of the accelerator pedal (7 in Pigure 1) out of its rest position can be fed at one input ôl to the limiter circuit 77. The input ôl for this pumpose is connected through a threskold value stage 83 to the switch 33 of the accelerator pedal. The limiter circuit clamps the cutput voltage of the integrator 51 likewise at a value within the proportionali tv range, it the accelerator pedel is not actuated, in the presence of the slip control signal.Finally a signal representing the clutch rest position is fed to the limiter circuit 77 at one input 85. For this purpose the input 85 is connected through a threshold value swith 87 to the position indicatcr 23 of the clutch pedal. In the precence of the control signal representing te clutch rest position the limiter circuit 77 reduces the regulation range of the integra- tor 51 in the release direction.

What is called "clutch rattle" occurs with the vehicle stationary and the gear in the neutral gear position, since in tis operational condition ordinarily the clutch pedal Is not depressed and the clutch ts is driving tre gear toothed eels, which as a rule are positively s@nchronised. In order to revert is te clutch control system 19 disengages the clutch when the vehicle is stationary and the gear in the neurtal position.

The neutral posit tion of the gear Is controlled without additional senscr on the gear in dependence upon the gear transwission rate, toe vehicle speed and the clutch pedal position.The seed Indicator 31 is connected for this purpose to one input 89 of a frequency/voltage converter 91 which converts the pulse sequence delivered by te speed indicator 31 intro a voltage signal proportional to the apeed-propor tional frequency of tis sequence.A threshold value switch 93 delivers a first control signal when the vehicle seed is lower than a speed lying in the range of pedestrian walking speeds, for example less than 3 kph. A second control signal is generated by means of a thresbold value switch 95 connected to the frequency voltage converter 63, when the ear Input rotation rate is greater than t second predetermined rotation rate ng2.The rotation rate value n 2 is so dimensioned that it scannot occur below the travel ling speed detected by the threshold value swItch 93 with clutch engaged in any of the gear positions except the neutral gear position. the rotation rate thus lies likewise below the idling rotation rate of the engine and preferably corresponds to the rotation rate nml. A snitable value for ng2 lies for example at 300 rpm.The signal generated by the threshold value stage 87 and represanting the clutch pedal rest position serves as third control signal for the detection of the nsutral gear position. The three control signals are fed to an AND-gate @7 whict sets a memory 99 formed as filp-flop when the three conditions are present and thus the gear is simated in the neutral gear position.The Q-output of the memory 99 controls the switch 43 through the control logic 45 into a switch position 101 in which a voltage source 103, or example in the form of a potentiometer, delivers an ideal position signal to the servo-regulator cirouit 17 which controle the setting member 15 and thus the clutch 3 Into the disengaged position.The memory 99 holds the clutch 3 in the disengaged position until it is rest. The re-setting signal is generated by a threshold value switch 1C5 connected to the position emitter 23 0 the clutch pedal when the clutch pedal Is moved into its disengaged position. On depression of the clutch pedal the memory 99 is cleared and at the same time the switch 43 is switched over by means o te control logie 45 from the awitch position 101 into the switch position 47. In the switch position 47 subsequently the clutch can be engaged by means o the clutch pedal.

Figure 4 shows the programme course plan of the control logic 45 as it can be realised or example by switches and comparators. The disengagement condition for the neutral gear position has priority over the clutch actuation through the clutch pedal or the integrator 51.If the disengagement condition exists, toe control swItch- 43 is switched into toe switch position 101 and the clutch is dieengaged. if the disengagement condition is not present, the examinetion for maintenance of the slip conditions takes place with next lower priority.If the slip conditions are not present, for example in te absence of slip control signal of the AND-gate 71, then te control switch 43 is switched into the switch position 47 and the clutch is controlled in dependence upon the position of the clutch pedal. If the slip conditions are present, with next lower priority it is tested whether the ideal position signal conducted by the clutch pedal or the ideal position agignal conchcted ty the integrator effects the greater slip, that is to say represents a releaser position closer to the disengagement position. If the guidance of the servo-regulator circuit 17 lies at the clutch pedal, te control logic 45 switches the control switch 43 into te switch position ;7.

If the guidance of the aervc-regulator circuit i7 lies by the integrator 51, the control switch 43 is switched into the switch position 55.

Figure 6 shows details of the integrator 51, of the slip parameter adjusting circuit 61 and of the limiter circuit 77. The inputs of the sum-and- difference amplifier 57 of the integrator 51 are connected through series-resistors 107, 109 to the frequency/voltage converters 63, 69. An earthed capacitor 111 which together it the resistor 109 determines the time constant of the non-inventing input is connected to the non-inverting input.The tine constant is of such short dimensions that sudden variations of the engine rotation rate n1 ol toe engine rotation rate signal fed to the non-inverting input appear without substantial delay on the cuput 53 with an amplification of 1.The resistor 107 together with the capacitor 59 determines the integration tie constant of te integrator for the difference between the engine rotation rate signal and the gear Input rotation rate signal. She Integration time constant is considerably greater than the time constant of the non-inverting input, so that the signal at the output 53 delivers a mean value of the momentary angular speed difference o the engine rotation and the gear intut shaft rotation an it is ensured that the mean value can follow slow variations of the difference occurring by reason of slow variations of the engine rotation rate averaged over one revolution.The integrator 51 thus has two signal paths between its inputs and its cutput and in the case c a rapid variation o te mean engine rotation rate parmite a rapid, slip-dependent adjustrent of the clutch position, without the occurrence of time delays by reason of the averaging properties c the Integrator.

The slip parameter adjusting circuit comprises a preferably adjustable voltage source, here in the form of a potentiometer 113, which is connected through a likewise prefemably adjustable serjes resispor 115 to the inverting input of the eum-and difference amplifier 57. The inverting input 57 is utilissd as summation point so that the integrator 51 integrates the difference of the total signal of gear input rotation speed signal and the signal of the slip parameter adjusting circuit 61 on the one hand and The engine rotation rate signal on toe cther hand.Ey means of the slip parameter adjusting circuit 61 the slip characteristio (Figure 2) can be adjusted and especially the engine rotation rate at which the slip should be zero can be sat.

The slip parameter adjusting circuit 61 superimroses upon the gear input rotation rate signal a constant cr, In other forms of embodiment, an engine otati. rate - dependently varying offset voltage or an offset current. The offset voltage cr current is dimonsioned so that at the engine rotation rate at which the slip should be zero it com@ensates the gear input rotation rate signal.In tne circuit arrange- ment according to Figure 6 this signifies that a voltage sh@uld be set on the voltage source 113 which is equal to that generated by the frequency voltage converter 63 at the zero slip rotation rate. The resistor 115 determines te speed of variation with which the slip varies in dependence upon the engine rotation rate.

The limiter circnit 77 is conrected thrcugh a bias-generating divider circuit 117 and likewise the control switch 23 le connected through a resistance divider cirouit 117 with preferably variable bias to the cutput 53 of @@ integrator 51. The limiter circuit 77 comprises a plurality of selectively controllabel feedback @@rcuits 119, 121 and 123 which are connected ea@@ to toe divider circuit 117 no the output singale of which feed beck to the invertin input of the sum-s@@-difference amplifier 57.The feedback circuits 119, 121, 123 are of similer assembly so that @nly the feedback circuit 119 is to be explained. lt comgrises a comparator 125 the non inverting input of w@ich is connected to the resis- tance divider circuit 117 and the invertin input of which Is connected ith 2 preferably variable bias source 127. The output of the compemator 125 is connected through a capacitor 129 with the inverting Input. She time constant of the integrator formed in this way is less than that of the integrator 51. n output resistor 131 leading to earth and a resistor 133 leading to the inverting input of te aum-and- difference amplifier 57 are connected to te output of the comparator 125.The feedback circuit 119 is connected with the inverting input through a diode AND-gate 135 which forts the input 85 (Figure 3) for the control signal representing the rest position of the clutch pedal. The feedback circuits 121 and 122 are connected through controllable switches 137, 139 with the inverting input of the sum-and-difference amplifier 57, one control ewitches 137, 139 are controllable through the inputs 79 and 81 of the limiter circuit 77.

Figure 5 shows with a cuve 141 a typical course of a torque Mk transmitted by the clutch in dependence upon a voltage USoll fed to the servc-regulator circuit 17 and forming the ideal position signal. AK designates the completely disengaged condition and EK the completely engaged condition of the clutch. 143 designates the sliding point of the clutch characteris- tic at which the clutch begins to transmit an appreciable torque.While the releaser position is variable according to the ideal position signal USoll between the positions AK and EK by means of the clutch pedal, toe limiter circuit 77 limits the maximum range of regu- letion of the integrator to the ideal position signal range between the sliding point 143 and the clutch engagement position EK.The regulating range is reduced in order to prevent saturation phenomena of the integrator 51 and in order to accelerate the response of the slip reg@lation in the case of a deflection of the clutch pedal cut cf its rest position. Cn application of the signal representing the deflection of the clutch pedal out of its rest position to te input 85 of the diode AND-gate 135 the regulating range limit adjecent to the clutch disengagement position is raised to the engagement position, as indicated at 145 in Figure 5.

The control switch 137 in the feedback path of the feedback circuit 121 is closed when a signal representing the absent slip signal of the AND-gate 71 (Figure 3) is fed to its control input 142. The feedback circuit 121 then clamps the cutput signal of the integratcr 151 at a fixed value 143 (Fugre 5) within the regulation range of the slip regulator circuit. The corresponding is valid fon a further fixed value 145 with clutch further opened, when a aignal is fed to a control input 147 (Figure 6) of the control switch 139 which represents the tresnce o the slip signal of the AND-gate 71 and the simultaneously occurring deflection of the accelerator pedal cut o its rest position.

While the value 143 lies in the region c the clutch engagement position or distant from the clutch ongagement position by the order of magnitude of the slip value to be maintained by the slip regulator circuit, the fixed value 145 preferably lies in the sliding range of the clutch.

The pedal travel sdaptor circuit 49 as rerresented in Figure 3 permits a largely variable adartation of the pedal travel characteristic to the releaser position characteristic determining the transmitted torque of the clutch.Figure 7 shows represented diagrammatically by Z continuous line 151 the torque M, transmitted by the clutch in dependence upon the pedal travel, which designates the rest position of the clutch pedal by O@ and the fully depressed position by 100@ After the over-coming of the idle travel 153 the transmitted clutch torque decreases until at 155 it reaches the disengaged position and is moved further over a certain safety distance 137. The engage ment operation proceeds on release of the clutch pedal in the o@nverse sequence, the sliding point teing reached at 159 at which the torque transmission of the clutch commences. 161 dosignetos the point of maximum engino torque.The pedal travel rapge between the pointe 159 and 161 is the sliding range of the olutch utilised for the engagement of te clutch. The position of the sliding range is fixad by the design of the mechanical or hydraulic clutch actuation device both as regards its position in relation to the clutch rest position and as regards its percentage width, in rdation TO the entire pedal travel.

She pedal travel adaptor circuit 49 permits a non-linear variation of the pedal travel-torque characteristic. 163 designates with short dashes a oneracteristio at which the sliding range is prolonged tetween a sliding point 165 and the point of maximum engine torque 167. The enlargement of the sliding range permits more finely sensitive clutch engagement.

A det-and-dash line 163 desigrates a characteristic at which the sliding range is displaced a s a whole as regards ite position in relation to the pedal rest position. A courve 171 shows with long deshes a torquepedal travel characteristic at which the sliding range follows a non-linear ourve at which the torque varies in the range of the slinding point greatly and in the range of the maximum engine moment cnly sligntly in dependence upon the pedal travel. The ourves 163, 169 and 171 furthermore show that not only can the sliding point and the point of maximum engine torqus be displaced in relation to the pedel rest position, but also a prelongation of the idle movement with clutch engeged and of the asfety play with cluch disengaged is possible in the end positions of the pedal.

Figure 8 shows 8 simple form of embodiment of a pedal travel adaptor oircuit with which linear, kinking curves according to the curves 163 and 169 can be realised. The circuit comprises an impedance converter stage 175 with low output resistance, the input 176 of which receives the position signal of the clutch position indicator 23. An arrangement of resistors 177, 179 and 181 is connected to the cutput of the impedence converter stage 175. The resistors 177, 173, 181 are conrected with ore another. While the resistor 177 is connected to the output of the impedance converter stage 175 and thus is loaded with a voltage correspon ding to the clutch pedal position, the resistors 179 and 181 are connected to preferably adfustable voltage sources 183 and 185 resyectively.The volage sources 183, 185 in the example of embodiment as illustrated are potentiomenters connected between earth aud an operating voltage source. The resistor 181 is in turn formed as resistance divider, here as adjustable potentiomater, and at its tapping 187 delivers the ideal position signal of the servo-regulator circuit 17 fixing the relesser position. Two oppositely polarised diodes 189, 192 are connseted in paralied with the resistor 177.

The dodes @@@ and 191 by their threshold volvages limit the voltage inop on the reisotr 177 in which the current through @ne resistor 177 can vary linearly in eccordance with @hm's law. The valuss of the resistors 177, 1@3 and 181 and the biases of the voltage sources 183, 165 are so selected that the linear range coincifes with the sliéing range of the pedal travel. When the sliding point or the point of maximum engine torque is reached the voltage drop on the resistor 177 inepch case resches the toreshold voltage of one of the two diodes and the ahort-circuit current flowing then through the diode short-circ@its the resistor 177. Thus the volta.-e divider ratio, seen from the output 187, varies and correspondingly so does the steepness of the ideal position signal/pedal twavel characteristic.

Claims

Claims:

1.) Clutch equipment for a motor vehicle, comprising a) a friction clutch (3) with a clwtch releaser (9) the position of which deterrines the torque transmittable by the friction clutch (3), b) 2 setting drive (15, 17) positioning the clutch releaser (3), c) a clutch actuation device (21, 23, 29) fixing the position of the clutch releaser (9) selectively between a completely disengaging release position and 2 completely engaging engagement position, d) an engine rotation rate Indicator (27) detecting the engine rotation rate, e) a gear rotation rate indIcator 2O) detecting the gear input rotation rate, f) a slip regulator circuit (56, 61) which acn- trols the setting drive (15, 17) in dependence upon the detected engine rotation rate and the detected gear input rotation rate in relation to the position of the clutch releaser (9) determined by the clutch actuation device (21, 23, 49) in such a way that the rotation rate difference between te engine rotation rat and the gear input rotation rate is aubstantially eqA to a predetermined rotation rate difference, characterised in that an averaging circuit (51) generates a mean value aignal corresponding to the mean value in time of the rotation rate @ifference @etween tne .~ detected engine rotation rate and te detected input rotation rate, and related to a time interval of constant duration and in that te slip regulator circuit (51, 61) controls the setting drive (1, 17) In dependance upon the mean value signal.

2.; Clutch equipment according to Calim 1, characterised in that the setting drive is formed as position servo-àrive (15, 17) which adjusts the position of the clutch releaser (9) to a position fixed by an ideal position signal and in thet both the actwating device 21, 23, 49) and the slip regulator circuit (51, 61) generate ideal position signals for the control of the position servo-drive (15, 17).

3.) clutch equipment according to Claim 2, characterised in that a control circuit (43, 45, 73) compares the ideal position signals of te actuating device (21, 23, 49) and of the slip regulator circuit (51, 61) with one another and switches off the ideal position signal of the slip regulator circuit (51, 61) from the position servo-drive (15, 17) when the ideal position signal of the actuating device (21, 23, 49) represents 2 position, lying closer to the disengagement position than the ideal position signal cf the slip regulator circuit (51, 61).

4.) Clutch equipment according to Claim 3, characterised in that the control circuit (43, 45, 73) switches off the ideal position signal of the actuating device (21, 21, 49) from the position servo drive (15, 17) when the ideal position signal of the actuating device 21, 23, 49) represents 2 position lying closer to the clutch engagement position than the ideal position signal cf the slip regulator circuit (51, 61).

5. Clutch equipment for a motor vehicle as claimed in Claim 1, substantially as herein described with reference to and as illustrated by any one of the examples shown in the accompanying drawings.

5.) Clutch equipment according to one of te preceding Claims, characterised in that the averaging circuit (51) comprises to signal paths for signals representing the rotation rate difference, of which te one signal path comprises an integrator (57, 5,) for the averaging cf engine rotation rate fluctuations by reason of irregularities o rotation and has a time constant which is greater, especially many tires greater, than the time constant of the other signal ath.

6,) Clutch equipment according to Claim 5, characterised in tat the averaging circuit (51) compri- ses a sum-and-difference emplifier (57) the inverting input of which is consected with its cutput through a capacitor (59) and receives a signal proportional to the gear input angular speed through an input resistor (107) and the non-inverting input of which receies a signal proportional to the engine angular speed through an RC circuit (1C9, 111) with smaller time constant than te t---e constant effective at te invertin input.

7.) Clutch equiprent according to one of Claims 5 cr 6 characterised in that a limiter cironit (77) limiting the output signals of the integrator (57, 59) to its proportionality renge is connected to the integrator (57, 50).

8.) Clutch equipment according to Claim 7, characterised in that the limiter cireuit (77), in dependence upon a eignal representing the absence of actuation of an accelerator pedal and/or upon a singe repressnting the ewitching to effectiveness of the slip regulator circuit i51, 61), fixes the integrator (57, 59) at a predetermined value of its output signal, if the accelerator pedal (7) is not actuated and the slip regulator circuit (51, 61) is effective or if te slip regulator circuit (51, 61) Is not effective.

9.l) Clutch equipment according to Claim 7 cr 8, characterised in that the liniter circuit (77) limite the position regulation range of the integrator (57, 59) TO position values of the setting drive (15, 17) between the engagement position and c posItion in the region of a sliding point position representing te commencement of torque transmission c the clutch (3) and in that the limiter circuit (77) rescs to a signal chich represents the positioning of the clutch releaser (9) by means o the actuating device (21, 23, 49) at a position departing from te clutch engage- mant position and upon tis signal limits toe range of regulation of the integtrator (57, 59) to position values between the engagement position and a position between the engagement position and the sliding point position.

10.) Clutch equipment according to one of the proceding Claims, Ctarecterised in that the slip regulator cirouit (51, 61) comprises a slip value control circuit (61) verying the predetermined rotation rate difference in dependence upon the engine rotation rate.

11.) Clutch equitment according to Claim 10, characterised in that the slip value control cirouit (61) reduces the predeterni ned rotation. rate difference to zero with increasing engine rotation rate.

12.) Clutch equipment accord to Claim 11, characterised in that the slip value control circuit (61) reduces the predetermined rotation rate difference to zero in a range of engine rotation rate between 2,000 and 2,600 revolutions per minute.

13.) Clutch equipgent according to one cf Claims 10 to 12, characterised in that the slip value control circuit (61) over-raises the predetermined rotation rate difference in resonance manter in the range of mechanical resonance frequencies of the engine-gear line.

1@.) Clutch equipment according to one of Claims 6 to 9 and one of Clains 10 to 13, characterised in that te slip value control circuit (51) cot-prises to series resistors (107, 115) connected each with a first connection to te irvarting input of te sum-and- difference amplifier (57), of which resistors the one is coupled with its second connection wits the gear rotation rate indicator (29) and the other with its second connction it a voltage source (113) an in that the voltage source (113) snd the gear rotation rate indicator (29) generate equel currents on the second connections oX toe two series resistors at that engine rotation rate at OIOh toe predetsrmined rotation rat difference is zero.

15.) Clutch equipment according to one of the preceding Claims, charscterised in that the slip regulator circuit (51, 61) comprises 2 control stage (71, 73, 75) responding to the detected engine rotation rate and the detected geer input rotation rate, which control stage switches the slin regulator circuit (51, 61) to effective w@en the engine ronation rate is greater then a firat predet @rmined rotation rate value which in turn is less than the ldling rotation rate of the engine nd at the same time the er Input rotation rate is less than S second predetermined rotation rate value which In turn is greater than the idling rotation rate of the engine and switches the slip regulator circuit (51, 61) to ineffective when toe ensir.e rotation rate is less than the first pre- determined rotaticn rate value or when toe gear input rotation rate is greater then the second pre- deter@ined rotation rate value.

16.) Clutch equipment according to Claim 15, characterised in that the first predetermined roation rate value lies in the range of 300 revolutions par minute and the second predetermined rotation rate value lies in the range of 2,400 revclutions pe@ mimute.

17.) clutrch equigment for a motor vehicle, comprieing a) a friction clutch (3) with a clutch releaser (9) the position of which determines the torque transmittable by the friction clutch '3), 2 2 setting drive (15, 17) positioning the clutch releaser (Oj) c) a clutch actuation device (21, 23, 29) determining the position o the clutch releaser 9) selectively between a completely disengaging releass position and a completely engaging engagement position, d) an engine rotation rate regulator (27) detecting the engine rotation rate, espacially according to one of Claims 1 to 16, characterised In that S speed indicator '31) responding to the vehicle speed is provided which gen retes a first signal representing the halting of the vehicle or vehicle speeds In the range of pedestrian walking speeds,- in that te clutch actuation device (21, 23, 49) in the case of presence of its ideal position signal fixin the clutch engagement position generates a second signal representing this operational ccnnltlen, and in that a disengagement control system (97, 99, 103) generates an ideal position signal cuntrolling the setting drive (15, 17) independently I toe clutch actuation device (21, 23) into toe disengagement position when the first and the second signal are sresent and the detected gear input rotation rate is greater than a prodetersined rotation rate value which in turn is lose than the idling rotation rate of the engine.

18.) Clutch cuitment according to ClaIm 17, characterised in that the disengagement o@ntrol system (97, 99, 103) camprises a memory (59) which is set In the presence of the dieengagement condition and holds the servo-drive (15, 17) in the disengagement position and in thet the clutch actuation device (21, 23) in te presence o its ideal position signal fixing the dIsengagement position generaTes a third signal representing this operational condition and feeds it to the memory (99) for the clearing of the stored disengagement condition.

19.) Clutch equipment for a motor vehicle, comprising a) a friction clutch (3) with a clutch releaser (9) the position of which fixes the torou-e transmittable by the friction clutch (3), b) Z setting drive (15, 17) positioning the clutch releaser (9).

c) a clutch tedal (21), d) 2 position indicator (23) controlling te setting drive (15, 17) and coupled with the clutch pedal (21), especially according to one bf the preceding claims, characterised in that the position indicator (23) generates an alectric control signal representing the position of the olutch pedel (21), in that an slectric adapror device (49) is provided which fixes a predeterrined non-linear relationship between the position of the clutch pedal 21) and the control signal and in what the setting drive (15, 17) comprises an electric position regulator cirouit (17) which adjusts the position of the clutch releaser (9), through an electrically controllable setting member (15), to a position fixed by the control signal as ideal value information.

20.) Clutch equipment according to Claim 19, characte@ised in that the position indicator (23) is formed as potentiometer which bas a non-linear resietance conracteristic for the formation of the adaptor device.

21.) Clutch equipment according to Claim 19, Characterised in that the adaptor device (49) is forred as dicde-resietance network (177, 179, 181, 189, 199) and is connected between the position indicator t23) and the position regulator circuit (17.

22.) Clutch equipment according to Claim 21, characterised in that the diode resistance network is formed as resistance divider circuit (177, 179, 181) and in that at least one diode, preferably to oppositely polarised diodes (169, 199), is or are connected in parallel with at least one of the resistors (177) of the resistance divider circvit (177, 179, 181).

23.) Clutch equipment for a motor vehicle as claimed in Claim 1, substantially as herein described with reference to and as i3lustrated by any one of the examples shown in the accompanying drawings.

CLAIMS Amendments to the claims have been filed as follows 1. Clutch equipment for a motor vehicle, comprising a) a friction clutch (3) with a clutch releaser (9) the position of which fixes the torque transmittable by the friction clutch (3), b) a setting drive (15, 17) positioning the clutch releaser (9), c) a clutch pedal (21), d) a position indicator (23) controlling the setting drive (15, 17) and coupled with the clutch pedal (21), especially according to one of the preceding Claims, characterised in that the position indicator (23) generates an electric control signal representing the position of the clutch pedal (21), in that an electric adaptor device (49) is provided which fixes a predetermined non-linear relationship between the position of the clutch pedal (21) and the control signal and in that the setting drive (15, 17) comprises an electric position regulator circuit (17) which adjusts the position of the clutch releaser (9), through an electrically controllable setting member (15), to a position fixed by the control signal as ideal value information.

2. Clutch equipment according to Claim 1, characterised in that the position indicator (23) is formed as potentiometer which has a non-linear resistance characteristic for the formation of the adaptor device.

3. Clutch equipment according to Claim 1, characterised in that the adaptor device (49) is formed as diode-resistance network (177, 179, 181, 189, 199) and is connected between the position indicator (23) and the position regulator circuit (17).

Clutch equipment according to Claim 3, characterised in that the diode resistance network is formed as resistance divider circuit (177, 179, 181) and in that at least one diode, preferably two oppositely polarised diodes (189, 199), is or are connected in parallel with at least one of the resistors (177) of the resistance divider circuit (177, 179, 181).