DE4431640A1 - Vehicle with hydrodynamic torque converter and method for controlling a torque transmission system with a torque converter - Google Patents

Abstract

The invention relates to a drive system comprising internal combustion engine and slip-controlled lock-up clutch for a hydrodynamic torque converter.

Description

The invention relates to a drive system Internal combustion engine, in particular for motor vehicles, the has a hydrodynamic torque converter, and a lock-up clutch acting in parallel with this, the is slip controlled, so that the transmissible by this Moment depending on the existing operating conditions to a specific one dependent on these operating conditions Size can be adjusted.

The invention further relates to a method for Controlling one with the output part of a drive unit, for example the internal combustion engine of a vehicle, operatively connected and with the input part of an automatic Torque-related gearbox Transmission system that a hydrodynamic torque ment converter and a parallel friction clutch Measured value recording system and a central processing unit or has a processor, the application of force to the Friction clutch and thus the one that can be transmitted by it Torque in cooperation with the central processing unit  is specifically changeable.

The invention is said to be advantageous in drive systems or in the case of torque transmission systems find a hydrodynamic torque converter have with a pump wheel, a turbine wheel, a Idler and a centric to the axis of rotation with the pumping wheel connected in terms of drive as well as the turbine wheel closing converter housing, where locally between a radial area of the converter housing and the turbine wheel Ring piston is provided, the radially outside with at least a clutch friction surface is provided and radially on the inside an output component of the torque converter, such as. B. one Hub or a gearbox input shaft, centered positio is nated.

Such drive systems or torque transmission systems are, for example, by DE-OS 31 30 871, the US-PS 5,029,087 and US-PS 4,577,737 become known.

By the aforementioned prior art are also Method for controlling torque transmission systems become known, in which by targeted adjustment of the Pressure in an actuation chamber or the differential pressure between the pressure on both sides of a piston one parallel to a converter and this if necessary bridging friction clutch that of the latter torque to be transmitted is set.  

So in DE-OS 31 30 871 in connection with a Torque transmission system of the type specified above Control procedure described, in which the between arrival and Slip values occurring on the output side measured with predefined slip values are compared and possibly determined countered differences. The latter happens in such a way that the fluid pressure in a chamber is regulated such that a speed difference between Input and output side at least in a lower speed range is set rich. It is therefore an on the classic slip control based control method.

A control method is also known from US Pat. No. 5,029,087 for converters with a friction clutch arranged in parallel previously known, where the slip measured at the clutch, compared with predetermined target slip values and in Ab dependency on discrepancies of the pressure in the Release chamber of the friction clutch is changed. Here too is a typical slip control, in which slip at least in a lower speed range is regulated.

Such systems with targeted influencing of the Friction clutch of a torque transmission system have transmissible torque discussed above in practice as not or at least not full proven satisfactory. The systems according to DE-OS 31 30 871 and US-PS 4,577,737 in one to the  Subsequent idling speed of the internal combustion engine low or low speed range slip in the Clutch set. In this lower speed range the system is considered over the total operating time however operated predominantly, so that due to the existing NEN slip, which in these known systems for Vibration isolation is required, an increased ener energy consumption or fuel consumption. Farther can the slip or the speed difference between the drive side and the output due to the existing in this speed range Operating conditions or sizes, such as in particular the adjustable contact pressure to close the bridging coupling, not to a desired low per se Value can be set. This is one of the reasons attributed to that in the converter or on the piston the lockup clutch required low pressure levels for the upcoming low torques one precise adjustment of this pressure level to achieve a defined slip is very difficult. Because of the the necessary low pressure levels result in low ones Pressure fluctuations make significant changes in slip number of revolutions. It should also be borne in mind that also for Regulation or control of the torque converter required Chen valves have a certain hysteresis, the z. B. on the friction of the pistons on the housing can be attributed so that a certain pressure level is also required for these valves is to ensure proper functioning.  

The possibility of precise control of the over bridge clutch to be transmitted torque is all the more the smaller this moment gets worse. Still exists the problem with these known systems that due to in the mentioned lower speed range of the drive motors in many operating and driving conditions low load or due to the upcoming relative low mean moment and the superimposed on it Torque fluctuations with a relatively low amplitude it between the friction surfaces of the clutch too short Conditions of detention come, to which there is again a glide period connects. Through these stick-slip transitions Introduce impulses into the drive train or into the gearbox tet that cause rattling noises in the transmission and / or trigger a hum in the drive train or in the motor vehicle can. The stick-slip transitions cause in particular abrupt changes in the transmission input torque. Such stick-slip transitions can only be done by adjustment a correspondingly large slip value can be avoided, which is disadvantageous from an energetic point of view is.

A disadvantage of the known systems is the fact that in the lower or low speed range in which the system is operated predominantly with partial load, which is operated by The torque to be transmitted to the friction clutch is very low high effort set to the desired low value can be and because this torque is not alone  from the clutch engagement force, but also from the coefficient of friction of the Friction lining is dependent, which in turn in Depending on the temperature, the slip speed, the Behavior of the oil used and other influences is subject to strong fluctuations. That means that at the known systems have a minimum slip speed in order to cope with fluctuations in system behavior a sufficiently high slip speed for vibration isolation to guarantee.

The present invention was based on the object to eliminate the aforementioned disadvantages and thereby a better vibration isolation between the drive machine and to ensure the downstream drive train. Furthermore, the lock-up clutch according to the invention an inexpensive construction for a torque converter and have a space-saving or compact design. Another object of the invention is to provide the over to design the bridging clutch so that it over entire operating range of the drive system or torque transmission system a perfect vibration insulation guaranteed, without an increased Use of energy or fuel is required.

The objects underlying the invention can be achieved by Use of a torsion damper can be solved, which the vibrations transmitted by the lock-up clutch or Torque irregularities at least to an acceptable level  Dimension dampens or filters, whereby the stroke torque of the door sion damper, i.e. the maximum of the damping means, how springs transmissible moment is smaller than the nominal torque, i.e. the maximum torque of the internal combustion engine seem. So that means that according to the invention of Torsion damper not as in the previously known state of the Technology on the full load of the drive unit or the Internal combustion engine is designed. As soon as the stroke torque is reached, the lock-up clutch behaves or whose torsion damper in the drive direction of rotation practically as rigid drive link. The fact that the invention Torsion damper for a lock-up clutch of a hydrodynamic torque converter to only one This torsion damper can be designed for partial load are particularly easy to build, which also makes a cost-effective production is guaranteed. Farther can the energy storage of the torsion damper, as in special coil springs to be designed weaker, so that they also require less space, which the one for the lock-up clutch or the torsion damper required space can also be reduced. This also results in a weight saving. Around the energy storage of the torsion damper against an overload to protect it, it is useful if between the Input part and the output part of the torsional vibration damper of the lock-up clutch special stops be provided.  

For most applications, it has proven to be useful proven when the stroke torque or the bridging torque of the torsion damper on the order of 10 and 60% of the maximum, i.e. nominal, moment of burning Engine is, preferably in the order of 25 to 50%. For some applications, the bridging However, the torque or stop torque of the torsion damper also have larger or somewhat smaller values. According to a further development of the invention has such a placed torsional damper for a lock-up clutch none special friction device. So that means that between the input part and the output part of the torsion damper only energy stores are provided, which are one Oppose relative rotation between these parts.

Due to the inventive design of the torque carrying capacity of the torsion damper Partial load range, i.e. in the area with drive torques in the Order of magnitude between 10 and 60% or between 25 and 50% vibrations occurring at the nominal moment very well be dampened.

It can be particularly useful if the damper one Allows angle of rotation compared to the previously known Twist angles of dampers for converter lockup clutch lungs is relatively small. This angle of rotation can in the Order of magnitude from ± 2 to ± 8 °, preferably in sizes order of ± 3 to ± 6 °. The total twist angle of the  Damper, i.e. the total angle of rotation for both rotary directions tion is thus 4 to 16 °, preferably 6 to 12 °. Due to the relatively small twist angle Torsion damper designed according to the invention for lock-up clutches it can be ensured that in the event of a load change, i.e. when changing from overrun to train operation and vice versa, the deflections in the damper are small be, causing a rocking of the drive train can be limited or avoided. Advantageously can the torque surges or the torque components of these Shocks that exceed the torque of the torsion damper lie, by slipping or slipping through the bridging clutch steamed or filtered so that this at least essentially from the drive train or from Gears are kept away.

For most applications, it can be useful if the damper has a torsional stiffness that is in the Order of magnitude between 7 and 30 Nm / ° preferably between 8 and 15 Nm / °. For some applications this can However, torsional rigidity is also chosen to be smaller or larger become. For most applications, the About bridge clutch or the torsion damper designed in this way be that this is a stroke torque of the order of magnitude between 30 and 90 Nm, preferably of the order of magnitude between 40 and 70 Nm. For weakly motorized However, vehicles can also use a smaller torque be interpreted. It may also be necessary to  highly motorized vehicles with relatively high Weight to make the stroke torque larger.

The drive system according to the invention can be advantageous Way in connection with a method for controlling an in Slip-controlled dependence of the applied torque Lockup clutch can be used, the one after energetic and performance-related aspects oriented control at least in all forward gear stages of a transmission. The invention However, the drive system can also be used in connection with gears controls or regulations are used that are used in the first and / or the second forward gear stage or stages leave the lock-up clutch fully open.

In particular, the configuration of the Drive system or the lock-up clutch in connection with a method for controlling a torque support system, as in the German patent application P 43 28 182.6 is used. Of the The disclosure content of this application is also intended to be a component of the present application. So it will be special with regard to the control options of the invention Converter lockup clutch related to this application taken.

According to a further embodiment of the invention, a drive system or torque transmission system of the type mentioned in the introduction, the torque control or torque control of the lockup clutch of a hydrodynamic torque converter can take place in such a way that the lockup clutch has at least two operating ranges in which the setting of the size of the the lock-up clutch transmissible torque with respect to the torque of the prime mover takes place according to other aspects or according to a different mode. So z. B. in a torque control according to the aforementioned German patent application P 43 28 182.6 at least one of the correction factors K _me (torque distribution factor), K _corr (correction factor to compensate for multiplicative incoming errors), M _corrMot (correction torque to compensate incoming errors additive to the engine torque) and M _corrWÜ (correction _torque for compensation additive to clutch torque incoming errors) weighted differently in the two operating ranges. This means that the size of at least one of these factors and thus also the effect of this size on the torque that can be transmitted by the lock-up clutch is defined differently in the two areas. It can be particularly advantageous if the torque that can be transmitted by the lock-up clutch is in the order of between 10 and 60%, preferably between 15 and 50% of the maximum torque of the drive machine, such as, in particular, the internal combustion engine, and in the second area that follows Range that the torque that can be transmitted by the lock-up clutch lies above the upper torque limit value of the first range, that is to say is greater than 50% or 60% of the maximum torque of the internal combustion engine. It can be particularly expedient if the maximum torque which can be transmitted by the lockup clutch in the first operating range corresponds at least substantially to the stop torque of the torsion damper of the lockup clutch. Such a design ensures that torque fluctuations with smaller amplitudes are intercepted or filtered by the torsion damper, whereas vibrations with torque peaks that are above the stroke torque of the torsion damper can be at least substantially dampened by slipping over the lockup clutch.

The torque control or torque control of the bridging Kungskupplung in the first area can advantageously done in such a way that that of the lock-up clutch transmissible torque at least essentially over the entire first area is larger than that standing moment of the internal combustion engine, which of this is generated due to the amount of fuel supplied to it. The torque that can be transmitted by the lock-up clutch can adjusted in this way over the first speed range be that this is at least essential Range of the first speed range approximately synchronous to Torque change of the internal combustion engine in the first area changed. So this means that if the the torque delivered by the internal combustion engine also that of  the lockable clutch transmissible torque decreases, whereby however, this remains greater than the moment of internal combustion machine. With an increase in the internal combustion engine The moment given will be that of the bridging clutch transmissible torque correspondingly larger. Appropriately it can be if it is from the lock-up clutch Transmittable moment 1 to at least 1.2 times the engine torque of the internal combustion engine is.

According to another embodiment variant of the invention in the first area from the lock-up clutch wearable moment at least approximately to a constant Value can be set, this value in sizes order between 25 and 60% of the maximum moment of the Internal combustion engine, preferably in the order of 30 can be up to 50% of the maximum torque. In advantageous This value can at least approximately match the stop torque ment or bridging torque of the torsion damper bridge coupling correspond, but preferably something be larger, e.g. B. 1.05 to 1.2 times this over bridging moment.

According to another sensible design variant, the Adjustment of the lockup clutch in the first Torque range of transmissible torque also take place in such a way that in a lower part of this first area, which is advantageously based on the idle speed of the  Internal combustion engine connects that bypass clutch transmissible torque at least approximately on one constant value is kept and in which it adheres closing second section of the first area moment transmissible by the lock-up clutch Torque development of the internal combustion engine follows. The latter means that if the moment of the internal combustion engine in the second sub-area becomes larger, the transferable moment of Lockup clutch also gets bigger and vice versa. In this second section is that of bridging clutch transferable torque at least the same size, preferred wise slightly larger than the respective moment of the Internal combustion engine.

To ensure precise control of the over bridge coupling to transmit transmissible torque afford, it can be particularly advantageous if that of the lock-up clutch in the first speed range portable moment not less than 1% of the nominal moment of the Internal combustion engine falls, is preferably kept larger than 1% of this nominal moment. This will make a minimum ensures pressure for the lock-up clutch, the with the known valves can still be set properly can. Due to the minimum pressure level, this can Pressure can be kept within relatively narrow limits.

For most applications, it can make sense if the first range from idle speed to a maximum of 3000  RPM, preferably up to a maximum of between 2000 and 2500 rpm is enough. For some applications However, it can also be useful if the upper Value above 3000 rpm or below 2000 rpm lies.

In the context of further training, the Invention that is transferable from the lock-up clutch Wait, over the entire operating range of the drive systems considered, such that in a first lower part of this overall operating area the Schwin tion decoupling at least essentially via the damper takes place and in a second subsequent Range essentially through the vibration decoupling Adjustment of slip in the lock-up clutch is guaranteed. In this second area the existing dampers temporarily come into effect, d. H. so the energy storage of the damper relaxed and be compressed again, however, this damper in this second area regarding vibration decoupling has a subordinate role.

The essentially designed for the first speed range The torsion damper of the lock-up clutch has priority wise, as already mentioned, a stop or bridging torque that is in the order of 10 to 60%, preferably between 15 and 50% of the maximum torque Internal combustion engine lies. However, the torsion damper can  according to a further embodiment of the invention also be interpreted in such a way that it follows the Angle of rotation, which is the aforementioned torque size corresponds to a relatively small twist kel, in which the spring rate is a multiple or is very steep, so that the torsion damper designated stop suspension, which is too hard Collision of the rotation limit in the torsion damper causing components prevented. This allows the eventu ell existing impact noise significantly reduced become. The ratio between that by the stroke spring tion enabled torsion angles and the rest of the formwork Teten residual angle of rotation can advantageously in the Of the order of 1 to 2 to 1 to 5, preferably in the Of the order of 1 to 2.5. The through the torsional stiffness is more advantageous Way 4 to 10 times larger than that of this stop suspension upstream torsional stiffness of the torsion damper. In This can advantageously be done by the stop suspension caused the end stop torque of the torsion damper the 2 to 5 times the aforementioned, at the end of the first area existing moment. It is advantageous however, the maximum transferable by the stop suspension Torque less than the maximum engine torque. The one through the Stop torsion angle covered between the Input part and the output part of the torsion damper can are on the order of 0.5 to 3 °, whereby it can be beneficial if this angle in sizes  order of 1 to 2 °. The stop suspension can also be designed so that they only in the direction of pull is effective.

By designing the torsional vibration damper for a lock-up clutch according to the invention can the one already mentioned and at a relatively small moment occurring hum problems can be eliminated. This is probably due to the fact that the mentioned Coupling phases of the coupling due to the torsionally flexible torsion damper can be bridged.

According to another useful development of the invention can the bridging clutch at least in the first Area transferable moment when conditions occur with high vibration amplitude in the drive train, that is z. B. with resonance, load change or the like, reduce be bar, causing the slip in the lock-up clutch is enlarged. In the event of a load change, if necessary Lich, in the overrun phase that of the lock-up clutch transmissible moment are practically completely reduced. A reduction in the torque transmission capacity of the Lock-up clutch in the aforementioned operating conditions gene can also advantageously in the second speed range done richly.

According to a preferred embodiment, the drive system or the transmission system can be designed in such a way  that at least the major portion of that in the main driving range used map of the internal combustion engine among the first Area falls. This main driving range can be advantageous Way at least the areas of the engine map that for the FTP75 cycle and / or for the ECE cycle city, Highway and motorway traffic (city, 90 km / h, 120 km / h) are relevant include. Such an interpretation will ensures that in the main driving area the vibration isolation practically predominantly takes place via the damper and thus the converter is almost always bridged, whereby an energy-saving or fuel-saving mode of operation is guaranteed. This is the case with the previously known Drive systems with slipping lock-up clutch not the case, since these are in the first speed range richly a slip is set like this from the state of the art at the beginning. Thereby, that according to the invention of the torsion damper the bridging Kungskupplung preferably on the main driving range is a much better damping of there occurring torsional vibrations are achieved as this a damper designed for a larger driving range training would be possible. In addition, there is a particularly compact converter design.

According to one embodiment of the invention can second speed range that of the lock-up clutch transferable moment, 0.6 to approx. 1 times each current moment of the internal combustion engine,  preferably 0.8 to 0.9 times. It is useful if the torque that can be transmitted by the lockup clutch in second speed range always below the pending Engine torque remains. Such an interpretation can be guaranteed that in the second operating area always there is little slip in the lock-up clutch is for damping the torque that occurs there uniformities which cause torsional vibrations, serves.

For non-critical vehicles, i.e. H. in vehicles that none in the second speed range or operating range major irregularities in torque delivery have, the lock-up clutch also practical be closed, that means that from the over bridging clutch transmissible torque at least that of the Engine delivered at the appropriate time Moment corresponds, preferably slightly above. The ratio can preferably be of the order of magnitude are between 1 and 1.2.

In the preceding description there is always talk of two operating areas, here areas are meant which connect to the idle speed. The invention however, it is not limited to embodiments in which the entire speed range of the drive systems above idle speed only in two Areas is divided, but is also on execution  variants aimed at the entire operating range is divided into more than two areas. So it can with some drive systems may be useful if the two areas already described a third area itself connects, whereby in this third area always one complete converter bridging is present. This third area thus includes a speed range that is above that of the second range, the lower value of this third speed range must be determined in this way be that there are no disturbing stimuli above this value gene can be done by the internal combustion engine, so that no vibration damping due to slip is required.

According to a development of the invention, one Transmission system with an internal combustion engine as an drive unit can be provided a device that at least in acceleration processes, determines whether by open the lockup clutch and maintain the same gear a tractive force increase through torque wall tion is achievable, in which case the bridging clutch is opened and the engaged gear is maintained otherwise the transmission will be at least one gear is switched back, the clutch then also closed can be opened at least partially, so that a slip increase in the lock-up clutch. The one mentioned The device can be controlled by an electronic computing unit or be formed a processor, which or which appropriate sensors the required sizes or parameters  ter receives. Some of these parameters can but also in the electronic unit in the form of folders or maps are saved. So z. B. that Map of the internal combustion engine and / or the map of the Converter and / or the map of the converter lockup clutch be stored in the electronic unit. Of the Operating state of the internal combustion engine can continue in Dependence on their speed, on the throttle valve angle or the amount of fuel supplied, the intake manifold vacuum and if necessary determined by the injection time become. Regarding a possible functioning of a such electronic unit for controlling a torque ment transmission system according to the invention referred to the German patent application P 43 28 182.6.

As already mentioned, in the case of the invention drive system from a certain engine speed or one certain speed of the vehicle also a full bypass of the converter, because above this Engine speed also on due to the full lockup practically stiff drive system with respect to that there occurring torsional vibrations is largely insensitive. So it can be above this certain engine speed Lock-up torque of the clutch to a value that corresponds approximately to or is greater than the engine torque, can be set.

The inventive design of the torsion damper in  Connection with the control strategy for that of the lock-up clutch transmissible torque can in Partial load range of the internal combustion engine on the friction surfaces the lockup clutch generated on transitions between Torque impulses due to sticking and sliding states, which can generate humming noises on the vehicle, at least be mitigated. Furthermore, in this first Area due to the set low bridging Do not build up any jerky vibrations at the moment of the clutch. The The softness of the torsion damper must match the respective Drive system or tailored to the respective vehicle become. Provided the torsion damper has a resonance range has to be traversed during operation of the vehicle must, as soon as this area occurs, one Allow slip in the clutch. This can cause a hum or rattle excitation can be prevented.

To limit the load change in the first area, serves not only the small twist angle of the torsion damper, but also the control of the lock-up clutch a moment in relation to the maximum moment of Internal combustion engine at a relatively low Level is. As already mentioned, the control in such a way that at least in the first operating area Torque transmission capacity of the lock-up clutch is only slightly above the existing engine torque. A Vibration excitation of the drive train through load changes gears can thus by the inventive design of  Drive system can be largely prevented. In the second Speed range of a higher load of the internal combustion engine machine corresponds to, is with a smaller moment than that standing engine torque bridged, so it happens Slip. This slip also has a noise-decoupling effect in a certain range of moments, especially in the closed interact with the torsion damper as it is in this Area still to stick / slip transitions between the friction surfaces of the lock-up clutch can come.

In the entire operating area or in the entire map area the drive machine, such as in particular an internal combustion engine, is preferably only bridged when it is out of energy technical reasons seems appropriate. Because there is Areas where it makes more sense to drive unbridged rather than partially or fully bridged. Also at Driver's desire to accelerate the lock-up clutch opened to bring about a torque conversion.

The drive system according to the invention and / or the Invention according process steps for setting the of the Lockable clutch transmissible torque can be in advantageously in connection with a soft torque ment converter find use. The characteristic Features of such a soft torque converter are in the German patent application already cited P 43 28 182.6, the disclosure content of which in connection with of the present invention.  

The use of such a soft transducer enables one better acceleration behavior in motor vehicles because such a converter a greater torque conversion owns and thus uses a larger area of change can be. In addition, it can be used in wide areas better efficiency of the soft converter compared to conventionally designed converters can be used, whereby the power loss and thus the consumption as well as the Oil temperature can be reduced. The area poorer efficiency of the soft torque converter is bridged or skipped by the Converter lock-up clutch in relation to that standing engine torque on a certain slip permitting torque value is closed. By a such regulation or control of the converter or its Lockup clutch can be ensured that in all driving conditions with better efficiency and with lower power loss can be driven. Thereby the inventive design of the drive system also bridging in all gear stages of the transmission is possible, the fuel consumption of the one such drive system equipped motor vehicle in essential to the level of a motor vehicle converter-free or conventional manual transmission reduced become.

Referring to Figs. 1 to 9, the invention is closer tert erläu.

Show:

Fig. 1 is a half sectional view of a schemati rule representation of torque-over tragungssystems with a converter and a lock-up clutch as well as a diagram of the associated Druckmediensteue tion,

Fig. 2 in a diagram the distribution of the engine torque in a converter of the torques and of the lung Überbrückungskupp moment to be transmitted in a depending ness of the occurrence of the slip of the converter and this bridging friction clutch,

Fig. 3 shows a torque transmission system with a hydrodynamic converter bridging friction clutch,

FIGS. 4 and 5 details of the Torsionsschwingungsdämp fers according to Fig. 3,

Fig. 6 shows a possible torsion characteristic of the damper of a lock-up clutch,

Fig. 7 is a view the output characteristic diagram of a "soft" converter,

Fig. 8 is a torsional vibration damper in view,

Fig. 9 shows the torsional vibration damper according to FIG. 8 and the adjacent components of a torque converter in section.

The torque transmission system 10 illustrated in Fig. 1 includes a torque converter 11 and a fluid pressure lock-up clutch 12 which is connected in parallel to the torque converter. The torque transmission system is with the only indicated shaft 13 of an internal combustion engine not shown, connected and is in turn on the output side via an output part 14 with a subordinate automatic transmission in the drive train in drive connection, which is also not shown.

As the schematic half-sectional view of the torque transmission system 10 in connection with the pressure control scheme shows, the torque converter 11 is a conventional flow converter. This flow converter consists of a converter cover 16 connected to the output of an internal combustion engine, a pump wheel 17 forming the converter housing together with the converter cover, a turbine wheel 18 connected via an output hub 14 to the automatic transmission (not shown) and a wheel 18 between the pumps. and turbine wheel arranged stator 19 . The converter bridging friction clutch 12 is arranged between the turbine wheel 18 and the converter cover 16 and has a rotationally connected to the output hub 14 or connected to the turbine wheel 18 of the converter clutch disc 20 , the friction surface 21 cooperates with a counter surface 22 of the converter cover 16 . The friction clutch further has a turbine wheel 18 facing rear chamber 24 and a radial wall of the converter cover 16 facing front side For term chamber 25th The clutch disc 20 has a piston 20 a axially separating the two chambers 24 , 25 , which is connected to the output hub 14 via a torsion damper 20 b.

The converter 11 is supplied in a known manner via a pump wheel on the side opening into the converter housing 30 from a pressure medium source, not shown, with flow pressure medium, the pressure being controlled by a control valve 31 , which in turn is controlled by a control element 32 . This control element 32 can be formed by a proportional valve or a pulse width modulated valve that is set via a computing unit or a processor 32 a, depending on the pending input variables or parameters as well as the maps stored in the processor. The flow pressure medium is discharged via a line (not shown) to a cooler 33, which is only indicated. In addition to the loading of the turbine wheel 18 of the pressure of the fluid pressure means on the downstream side of the impeller 17 acts also in the rear chamber 24 of the friction clutch 12th The pressure medium acts on the piston 20 a and presses it against the counter surface 22 of the converter cover 16 . Since according to the invention, the clutch, at least surfaces in some operating preparation driven with slip, the flow pressure is mittelbeaufschlagung the front chamber 25 by means of an associated with this chamber via a line 34 valve 31 controllable so that an adjustable and between the rear 24 and front side chamber 25 effective differential pressure determines the torque that can be transmitted by the friction clutch 12 .

In view of the parallel arrangement of the converter 11 and the latter bridging friction clutch 12 , the engine torque is equal to the sum of the moments transmitted by the converter or the pump wheel and by the clutch, ie

M _motor = M _clutch + M _{pump wheel} .

The transmission torque, as far as losses from transmission system is equal to the sum of that from the converter or moments transmitted to the turbine wheel, that is

M _gearbox = M _clutch + M _{turbine wheel} or M _clutch + (M _{pump wheel} × conversion).

The division of the engine torque into a torque to be transmitted by the converter and by the bridging friction clutch is illustrated in FIG. 2 as a function of the slip. It can be seen that with increasing slip, the portion of the engine torque transmitted by the converter increases and, accordingly, the torque transmitted by the clutch drops.

In the preferred control method, however, in operating states in which slip is desired, this not directly regulated, but the intended function of the operating state of the engine by the friction clutch 12 to be transferred proportion of the engine torque and of a computer unit, such as a microprocessor 32 a, the differential pressure necessary for the transmission of the predetermined torque is set on the friction clutch. The slip then arises automatically.

The torque transmission system 110 illustrated as an exemplary embodiment in FIG. 3 is a hydrodynamic torque converter 111 with a lockup clutch 112 and a damper unit 135 which acts between the torque converter and the lockup clutch.

The torque converter 111 comprises a pump wheel 117 which is connected to a non-illustrated internal combustion engine in a rotationally fixed drive connection, a turbine wheel 118 which is operatively connected to an output-side hub 114 , a stator wheel 119 arranged in the flow circuit between the pump wheel and turbine wheel, and a stator wheel connected to the pump wheel in a rotationally fixed manner and enclosing the turbine wheel Converter cover 116 .

The converter cover 116 is non-rotatably connected to the pump wheel 117 and provides its drive connection with the internal combustion engine via driver areas 116 a projecting on the side facing away from the pump wheel 118 , to which a drive disk (not shown) of the internal combustion engine can be fastened.

Between the turbine wheel 118 and the radial region of the converter cover 116 , an annular piston 136 is arranged to the axis of rotation of the converter, which is a molded sheet metal part. This annular piston is received radially on the inside on an output hub 114 connected in a rotationally fixed manner to the turbine wheel 118 and forms a conical area radially on the outside, which is equipped with a suitable lining 121 . The annular piston 136 interacts with a correspondingly conical counter-friction surface 122 of the transducer cover 116 .

The lock-up clutch 112 has a rear pressure chamber 124 between the annular piston 136 and the turbine wheel 118 and a front pressure chamber 125 between the annular piston 136 and the converter cover 116th The piston 136 is actuated in its coupling position, which cooperates with the counter friction surface 122 , by applying fluid to the front pressure chamber 125 . The magnitude of the torque to be transmitted by the friction clutch 112 is dependent on the differential pressure set between the pressure chambers 124 , 125 .

The torsion damper 135 is designed such that its bridging torque or stop torque is less than the nominal torque, ie the maximum torque of the torque converter driving the internal combustion engine 110 . So this means that the energy storage 137 of the torsion damper 135 are designed such that they can not intercept the full torque of the internal combustion engine. The relative rotation between the input part 138 of the torsion damper 135 , which is connected in a rotationally fixed manner to the piston 136, and the flange-like output part 139 can take place by blocking the turns of the springs 137 or preferably by stops provided between the input part 138 and the output part 139 . The output part 139 of the damper 135 is non-rotatably connected to the turbine hub 114 in a manner known per se via an axial plug connection formed by teeth.

As can be seen from FIG. 4, the input part 138 cooperating with the force-storing 137 can be formed by segment-shaped components 140 , two such components 140 arranged back to back being provided diametrically opposite each other. These pairs of segment-shaped components 140 are rotatably connected to the piston 136 via rivet connections 141 . In FIG. 5, the flange starting part is shown in elevation 139th The flange 139 has an annular base body 139 a and two diametrically opposed radial arms 142 with recesses 143 for the energy accumulator 137 . The arms 142 are received axially between the components 140 assigned in pairs. The segment-shaped components lying in pairs back to back form - viewed in the circumferential direction - 144 receiving pockets 145 for the brackets 142 between their fastening regions . In Fig. 5 the stop contours formed by the segment-shaped parts 140 are indicated 146 for the boom 142 through under brochene lines. The piston 136 has axial impressions distributed over the circumference, which form projections 147 directed in the direction of the turbine wheel 118 , on which the fastening regions 144 of the segment-shaped components 140 facing the piston 136 rest. The components 140 also have recesses 148 for the springs 137 . These recesses 148 are aligned in the illustrated embodiment with the recesses 143 of the output part 139 in the axial direction. In the leadership For example as shown in FIGS. 3 through 5, the force is taken up memory 137 without play in the recesses 143 and 148. For some applications, however, it can also be expedient if at least one of the springs 137 has play against a recess 143 and / or 148 . At least one of the springs 137 can also be installed in a window 143 and / or a window 148 with a certain prestress.

Characterized in that the torsion damper according to the invention is designed only 20,135 b or at a part-load range, it can be particularly simple design, thus also cost-effective manufacture is made possible.

According to an embodiment of the invention, the torsion damper 135 can be designed such that about 40 to 50% of the maximum, that is to say nominal, torque of the internal combustion engine can be transmitted via the springs 137 . The relative angle of rotation covered by the energy accumulator 137 between the input part 138 and the output part 139 can, as can be seen from FIG. 6, be in the order of 50. FIG. 6 shows the relative angle of rotation between the input part 138 and the output part 139 of the damper 135 when the motor vehicle is being operated by train. In the thrust mode this relative angle of rotation can be the same size or have a different value. Also, the torsional stiffness of the torsion damper 135 in the direction of pull and direction of thrust can be of different sizes. This is achieved by appropriate dimensioning of windows 143 and 148 and springs 137 . The torsion damper 135 can also have a multi-stage characteristic curve, wherein the characteristic curve areas which correspond to the overrun operation and the pull operation can also have different courses.

From Fig. 6 it can be seen that the torsion damper 135 is bridged at 50 angles or goes to a stop and is limited to approximately 45 Nm by the elasticity or compression of the springs 137 via portable torque. A torsion damper 135 designed in this way can advantageously be used in conjunction with hydrodynamic torque converters which have a slip-controlled lockup clutch. The 45 Nm stop torque is suitable for motors with a maximum nominal torque in the range of 80 to 200 Nm.

The bridging torque of the damper 135 is expediently dimensioned such that it preferably covers the entire main driving range of a motor vehicle. The main driving area is the area that is used most frequently over the entire operating life of a motor vehicle. This main driving range expediently comprises at least the areas of the engine map which are decisive for the FTP75 cycle and / or for the ECE cycle (city, 90 km / h, 120 km / h). The main driving area is the area in which the vehicle is operated the most. Due to the existing transport infrastructure in the individual countries, this driving area can differ somewhat between the individual countries.

In the output characteristic diagram of a torque converter 110 with a soft converter design shown in FIG. 7, the main driving range is shown as a hatched area. Furthermore, the conversion range of the torque converter is shown in FIG. 7. The lockup clutch 112 is open in this conversion region. The main driving area is surrounded by an area in which driving is preferably carried out with a minimal slip in the lockup clutch 112 . The main driving range extends from a lower speed A to an upper speed B. The lower speed A corresponds at least essentially to the idling speed, which can be in the order of 700 to 800 revolutions. The upper speed limit B can be in a speed range between 2000 and 3000 revolutions and can have the value 2200 rpm, for example. The area with slip can have an upper speed limit c, which can correspond to the maximum speed of the internal combustion engine, but can advantageously also be lower and, for example, can have a value between 3000 and 4000 rpm.

By designing the torsion damper 135 according to the invention, the torque converter 110 can be completely bridged in the main driving range, that is, the bridging clutch 112 can be operated without slippage. In this main driving range, the vibration isolation between the internal combustion engine and the downstream transmission takes place practically completely via the torsional vibration damper 135 . Only peak moments are intercepted by slipping in the lock-up clutch 112 . For this purpose, the lock-up clutch 112 is controlled or regulated in the main driving range in such a way that it transmits a relatively small torque with respect to the maximum torque of the internal combustion engine, which torque is, however, greater than the torque of the internal combustion engine currently being applied.

In the area with slip, the lock-up clutch 112 is controlled or regulated in such a way that there is a certain amount of slip between the friction surfaces 121 , 122 of the lock-up clutch 112 . Because of this slip, there is also a relative rotation between pump wheel 117 and turbine wheel 118 .

In the area with slip according to FIG. 7, the disturbing torque irregularities still occurring in this area are mainly dampened by slip.

In the main driving area as well as in the area with slip, the transmissible torque of the lock-up clutch 112 can be reduced for better vibration isolation, if conditions occur in the drive train with a high vibration amplitude, that is, for example, in the case of resonance, load change or the like.

As can be seen from Fig. 6, the torsion damper of the lock-up clutch 112 can also be designed such that it has a relatively small angle of rotation after an angle of rotation with a relatively small angle of rotation stiffness, in which the torsional stiffness is a multiple of that of the first angle of rotation. In Fig. 6, this second twist angle extends over 20. The torsional stiffness in this second twist angle can be 7 to 15 times the torsional stiffness in the first twist angle. In the embodiment shown in Fig. 6, the torsional stiffness in the first angle of rotation in the order of 8 Nm / ° and in the second angle of rotation in the order of 70 Nm / °.

In the main driving range according to FIG. 7, the torque that can be transmitted by the lock-up clutch 112 is set to approximately 1.1 to 1.2 times the actual engine torque. The regulation or control of the torque that can be transmitted by the lock-up clutch 112 can take place in the main driving range in such a way that the torque that can be transmitted by the lock-up clutch 112 does not fall below a minimum value. This value should be at least 1% of the nominal torque of the internal combustion engine. The minimum torque that can be transmitted by the lock-up clutch 122 in the main driving range can be, for example, 5 Nm. However, this lower limit can be shifted up or down depending on the application. In this way, the minimum torque that can be transmitted by the lockup clutch 112 in the main driving range can also be set to a value that is very close to the maximum engine torque occurring in the main driving range, preferably a little smaller.

In the area designated “area with slip” in FIG. 7, the torque that can be transmitted by the lockup clutch 112 via the bypass clutch 112 is set to 0.8 to 0.95 times the instantaneous torque of the internal combustion engine. The torque transmission capacity of the lock-up clutch 112 is therefore dependent on the particular moment of the internal combustion engine that has to be transmitted. In other words, this means that with increasing torque of the internal combustion engine, the torque that can be transmitted from the lock-up clutch also increases and, with a decrease in the torque delivered by the internal combustion engine, the torque transmission capacity of the lock-up clutch 112 also decreases.

The embodiment variant of a lock-up clutch 212 for a hydrodynamic torque converter shown in FIGS. 8 and 9 has a two-stage torsion damper 235 which has a first set of energy accumulators 237 and a second set of energy accumulators 250 . The lockup clutch 212 is designed as a multi-plate clutch, with an inner plate carrier 251 and an outer plate carrier 252 . The outer plate carrier 252 is non-rotatably with the housing 216 of the torque converter. The disk carrier 252 carries a support plate 253 on its end region facing the turbine wheel 218 . The housing 216 forms in connection with a piston 236 a Druckkam mer 254 , which can be acted upon with a liquid medium to adjust the torque to be transmitted by the lock-up clutch 212 . The output part of the lock-up clutch 212 formed by the disk carrier 251 has a profiling 255 formed radially on the inside, which is engaged with play with a counter-profiling 256 of an output part in the form of a turbine hub 214 . The profiles 256 are formed by an annular component made of sheet metal, which is fixedly or rigidly connected to the hub 214 . The torsional vibration damper 235 has an input part 238 which is drivingly connected to the output part 251 of the lock-up clutch 212 . The input part 238 of the damper 235 is formed by a ring-shaped component, which has radially inside cantilevers or tongues 257 which engage in slot-shaped recesses 258 of the output part 251 of the lockup clutch 212 . This engagement ensures a practically backlash-free connection in the circumferential direction between the two components 251 and 238 . As can be seen in particular from FIG. 8, the annular component 238 has cutouts 259 , 260 for the energy stores 237 , 250 . The energy stores 250 are accommodated in the recesses 260 with play in both directions of rotation. The annular component 238 is received axially between two disks 260 , 261 . The two disk-shaped components 260 , 261 are potted toward one another radially outside the annular component 238 and are firmly connected to one another. The disk-shaped component 261 facing the turbine wheel 218 extends radially inward to the hub 214 and is connected to the latter in a rotationally fixed manner. As can be seen from FIG. 9, the outer turbine shell 218 a, the disk-shaped component 261 and the annular component 256 are rigidly connected to the output hub 214 together via connection points which are formed by rivet connections 262 . The torsional vibration damper 235 can have a torsional characteristic line 263 , 264 according to FIG. 6. The first characteristic curve region 263 is covered by the energy accumulator 237 . When the first angle of rotation range 263 is exceeded, the springs 250 additionally come into effect with a high spring rate parallel to the springs 237 . This results in the steep characteristic curve region 264 . At the end of the characteristic curve area 264 , the internal toothing 255 of the clutch output part 251 comes into contact with the external toothing 256 of the output hub 214 , as a result of which a positive, practically rigid connection between the component 251 and the output hub 214 is ensured - in the corresponding direction of rotation. The damper 235 is thus bridged by abutment of the toothings 255 , 256 . There is thus a to the running over the springs 237 , 250 power flow par allel power flow, which leads directly from the output part 251 of the lock-up clutch 212 into the output part 214 . Overloading of the springs 237 , 250 or the components 238 , 260 , 261 can thereby be avoided.

Due to the inventive design of the converter lockup clutch and its control, an optimal operation of a motor vehicle is possible from an energy perspective. Characterized in that in the mainly used operating states with slip-free lock-up clutch is driven, a substantial fuel savings can be achieved compared to the lock-up clutches that are not bridged or operate with slip in these operating states. The main speed range is between about 600 and 2200 to 3000 revolutions per minute or the mean value around 1800 revolutions per minute. In the main driving range, the lock-up clutch is therefore essentially closed, so that the prevailing motor torque is transmitted through the lock-up clutch without substantial slippage. The vibration damping takes place in this main driving range by the force or torque flow of the lockup clutch 12 , 112 , 212 before seen torsional vibration damper 20 b, 135 , 235 . The Tor sionsdämper 20 b, 135 , 235 is provided with a relatively small twist angle and the torque of the torsion damper corresponds approximately to the upper limit moment of the main driving range. This upper limit torque can be 15 to 50% of the maximum engine torque, depending on the engine and vehicle weight. With a damper constructed in this way, vibrations can be controlled in the driving area with lower drive torques, which produce a disturbing hum. Disturbing load change reactions in the drive train are suppressed or avoided by the relatively small torsion damper twist angle. The load changes are limited by the friction surfaces of the lockup clutch slip relative to one another when the stop torque or lockup torque of the damper is exceeded. This limits the moment of transmission. The torque peaks are dampened by slipping in the lock-up clutch. Above the main driving range or in the driving range in which the torques are greater than the limit torque that can be transmitted by the damper, the lock-up clutch is controlled in such a way that slip is present. Disruptive load change reactions are avoided by the slip set in this way. In speed ranges or torque ranges above the main driving range, in which there are no disturbing vibrations, the clutch can also be inferred about a torque value that is greater than the engine torque. For certain speed ranges in which disturbing excitations are present, the lock-up clutch can be opened again for slippage. The latter can be useful in particular when a resonance speed occurs.

Relatively in the main driving area or in the area Small engine torques can occur when driving through resonances be expedient to open the lock-up clutch or to significantly reduce the transmissible moment from this.

The inventive design and control or Regulation of the lock-up clutch should in particular so-called humming noises are eliminated, which over a partially closed, i.e. slipping bridging clutch can not be eliminated, because of the between the friction surfaces of this lock-up clutch occurring sticking / sliding conditions.

The invention is not described and described on the limited exemplary embodiments, but also includes  Variants, in particular by combining individual, in connection with the different embodiments described features or elements as well as functions can be formed. Furthermore, the in the previous inventions disclosed in the context of or in connection with the state of the art as well as the aforementioned older German patent application P 43 28 182.6 can be considered. The one in the present Registration cited prior art or the older one German patent applications are therefore intended to supplement the represent the present application.

The applicant also reserves the right to Features of. previously only disclosed in the description claim essential to the invention.

Claims (18)

1. Drive system with internal combustion engine and slip control 1st lockup clutch for a hydrodynamic Torque converter, the lock-up clutch Contains torsion damper, the stroke torque of which is smaller is the nominal torque of the internal combustion engine. 2. Drive system with internal combustion engine according to claim 1, characterized in that the stop torque between 10 to 60% of the maximum torque of the internal combustion engine is preferably between 25 and 50%. 3. Drive system with an internal combustion engine according to claim 1 or 2, characterized in that the damper none has its own friction device. 4. Drive system with an internal combustion engine according to one of the Claims 1 to 3, characterized in that the Damper has a relatively small twist angle in the Order of magnitude from ± 2 to 8 °, preferably from ± 3 to 6 °. 5. Drive system with an internal combustion engine according to one of the  Claims 1 to 4, characterized in that the Damper has a stiffness of 7 to 30 Nm / °. 6. Method of controlling one depending on the transmitting moment slip-controlled bridging clutch for a hydrodynamic torque converter, one according to energetic and performance related Control oriented from a point of view, at least in all Forward gear stages of a transmission is effective. 7. Method for controlling a drive system with a burner Engine according to one of claims 1 to 4 and 6, characterized in that the torque control of the Lockup clutch divided into at least two areas is, the first of which is in the range of 10 to 60% preferably from 15 to 50% of the maximum torque Internal combustion engine is sufficient and the second is above. 8. Method for controlling a drive system with a burner Engine according to claim 7, characterized in that in the first area that of the lock-up clutch transmissible moment is greater than the queue de torque of the internal combustion engine. 9. Method for controlling a drive system with a burner Engine according to claim 8, characterized in that the transferable from the lock-up clutch Moment 1.0 to at least 1.2 times each  current torque of the internal combustion engine. 10. Drive system with internal combustion engine and slip control 1st lockup clutch for a hydrodynamic Torque converter, the lock-up clutch Contains torsion damper, especially according to one of the preceding claims, characterized in that in first area the vibration decoupling at least in essentially done via the damper and in the second Area essentially over slip of the bridging clutch. 11. Drive system with internal combustion engine after at least one of the preceding claims, characterized records that in the first area in states with high Vibration amplitude in the drivetrain, that's for Example with resonance, load change or the like Chen, the transferable torque of the lock-up clutch can be reduced. 12. Drive system with an internal combustion engine according to one of the preceding claims, characterized in that the impact torque of the torsion damper at least approximately that occurring at the end of the first area Moment of the internal combustion engine corresponds. 13. Drive system with an internal combustion engine according to one of the preceding claims, characterized in that  at least over a partial area of the first area the minimum that can be transmitted by the lock-up clutch moment is kept larger than 1% of the nominal Mo mentes the internal combustion engine. 14. Drive system with internal combustion engine after at least one of the preceding claims, characterized records that at least over a portion of the first area that of the lock-up clutch transmissible moment at least approximately on one constant value is kept. 15. Drive system with an internal combustion engine according to one of the preceding claims, characterized in that at least the major part of that in the main driving range used map of the internal combustion engine (for play the areas of the engine map that are relevant for the FTP75 cycle and / or for the ECE cycle [Stadt, 90 km / h, 120 km / h] are relevant) under the first area falls. 16. Drive system with an internal combustion engine according to one of the preceding claims, characterized in that the first range from idle speed to a maximum of 3000 Rpm, preferably up to a maximum of between 2000 and 2500 RPM is enough. 17. Drive system with an internal combustion engine according to one of the  preceding claims, characterized in that in second area that of the lock-up clutch transmissible moment 0.6 to <1.0 times the respective current torque of the internal combustion engine, preferably 0.8 to 0.9 times. 18. Drive system with internal combustion engine, characterized records that at least during acceleration a facility determines whether by opening the About bridging clutch in the same gear an increase in tractive force can be achieved by torque conversion and in this Latch opens, otherwise the gearbox at least one Gear is downshifted.