Vehicle with a drivetrain having a multiple clutch device

[Technical Field]

p0001The invention relates to several main aspects generally a so-called multi-clutch device, if appropriate double-clutch device for arrangement in a motor vehicle drive train between a drive unit and a transmission, the clutch device assigned one of a first transmission input shaft assigned first clutch assembly and a second transmission input shaft second clutch assembly for transmitting torque between the drive unit and the gearbox, wherein the clutch arrangements are embodied as multi-plate clutch assemblies, to which an operating fluid, in particular a cooling oil, for operation under the action of the operating fluid can be supplied (in particular for a wet-running operation). It is thought in this regard, particularly (but not exclusively) to such a coupling device in which the multi-plate clutch arrangements are hydraulically operable means in the coupling device integrated hydraulic slave cylinders.

[State of the art]

p0002Such a clutch device is for example in the <patcit id="pcit0001" dnum="US5181431A"><text>US 5181431 A</text></patcit> proposed which discloses a motor vehicle according to the preamble of claims 1, 3, 11, 14, 18, 22 and 25th

p0003The invention relates to this main aspect, further comprising a drive train having a drive unit and a gear (possibly powershift) having a first transmission input shaft and a second transmission input shaft and a clutch device of the type mentioned, as well as a such a powertrain complete motor vehicle. There is particular need to consider getting in this context that the transmission, preferably designed as a power shift is assigned an actuator assembly and the actuator assembly-addressing controller, associated with the mediation of the first and second transmission input shaft gears switched on and interpretations.

p0004In order to prevent wear and burning of the blades (in particular lining disks), the lubrication / cooling of the blades is by a working fluid (in particular cooling oil) is required. Regularly employed for such applications oils have at operating temperature (90 ° C) to a low viscosity (low viscosity), so that with opened clutch assemblies (unpressurized hydraulic actuating cylinders in the case of hydraulically actuated clutch assembly of the NORMALLY-OPEN-type), the drag torque, which are caused by the left hand between the slats oil, are relatively low (eg less than 2 Nm). However, if the oil temperature is very low (about significantly less than 0 ° C), as may occur for example due to a nightly soaks of the motor vehicle in winter, results in a dramatic increase in toughness (viscosity) of the oil, and it can then very high drag torques occur ( up to levels exceeding 25 Nm). In addition to the drag torque breakaway or Loslösmomente of up to about 50 Nm may be due to each other adherent (to each other adhesive) slats occur, which would be at the start of the driving operation, but only once apply to solve the mutually adhering (another adhesive) lamellae from each other. After this loosening of the lamellae then occur but still the drag torques on until the resistance (viscosity) of the oil through the heating of the motor and the introduction of heat (frictional energy) decreases in the clutch assemblies.

p0005As a result of these high towing or stringing bonding moments gear engagement can be virtually impossible, because the synchronization of the transmission facilities are generally not designed for overcoming such high moments. Typically, the synchronizers for moments of the order 5 Nm are designed. Can not engage gears and can not be switched, as a driving the vehicle is not possible.

[Summary of the Invention]

p0006The present invention aims to solve the above problems, or at least mitigate, in particular to make better controlled. This object is achieved by a vehicle having the features of one of claims 1, 3, 11, 14, 18, 22 or 25th

p0007In normal driving conditions without strong acceleration or without starting with a heavy load (eg starting with a trailer), the operating fluid heated (cooling oil) is usually relatively slow. This means that also reduces the drag torque occurring in the clutch assemblies only comparatively slowly. It is therefore conceivable that the drag torques reach only after two or three minutes drive values ​​that allow a normal synchronizing without overloading or damage the synchronizers. Advantageously, to reduce the warm-up period is definitely the quantity of operating fluid (cooling oil quantity) as small as keeping essential. It should, furthermore, that the trailing torque greatly from the currently supplied operating fluid quantity (amount of cooling oil) increases. This indicates that supply only small amounts of liquid operation. On the other hand need to ensure proper cooling. It will search for and find a compromise between the necessary cooling and the smallest possible drag torques.

p0008A possibility for shortening the heating time is the targeted heating by introducing power loss in the coupling device, for example, by simultaneously pressing the two clutch arrangements, so that a part of the power of the drive unit (motor power) is reacted in the coupling device into heat.

p0009Another possibility for reducing the drag torque is that the supply of operating liquid is then reduced or stopped when no cooling or lubrication of the blades is needed. From this immediately results in a reduction of the drag torques, as this by located between the blades operating fluid (cooling oil) caused. It is according to a first main aspect of the invention for a motor vehicle comprising a drivetrain, which has: a drive unit, a transmission with a first transmission input shaft and a second transmission input shaft and a clutch device having a first clutch arrangement which is assigned to the first transmission input shaft and a second clutch arrangement which is assigned to the second transmission input shaft, for transmitting torque between the drive unit and the transmission, the clutch arrangements are embodied as multi-plate clutch assemblies, to which an operating fluid, in particular a cooling oil, for operation under the action of the operating fluid can be supplied through the intermediary of a pump arrangement, especially suggested that the pump assembly or a Flusseinstelleinrichtung is controllable by a control device in order to adjust an instantaneous operating fluid flow to the plate clutch assemblies, and that the control means is adapted, in response to a current supply need for operating medium to at least one of the clutch assemblies to increase the operating fluid flow and shrunk such that the control device decreases at lower feed requirement the operating fluid flow or breaks and greater supply required to operate the liquid flow is increased, the electronic control unit based on a temperature signal which originates from a temperature of the cooling oil detecting sensor, related to the time unit delivery volume of the pump assembly and / or a pressure-flow rate allowed a arranged in the circulation volume flow adjustment valve controls or regulates.

p0010For current drive unit, the operating fluid is ejected from the slats of the non-actuated clutch assembly by centrifugal force. This results in a significant reduction in drag torque. It is conceivable that the drag torques are reduced so far by this measure that even the engagement of gears on the respective transmission input shaft. So one could remember freizuschleudern for a start, for example, in 2nd gear, the clutch assembly is not used for starting, which is associated with the still reverse gear engaged, quickly and thus prepare for a shift to the next forward gear. This switch can then be generally normal and without undue stress on the synchronizers of the transmission and it is then unnecessary, unreasonable to expect the driver for safety reasons a speed limit (because of the still engaged reverse gear).

p0011A further development it is proposed that the control device determines the Zuführbedarf in view of occurring at the clutch assembly power loss and / or a lubricating need for the discs of the clutch assembly. This will always provide adequate cooling or lubrication.

p0012According to a second main aspect of the invention for a motor vehicle, comprising a drivetrain, which has: a drive unit, a transmission with a first transmission input shaft and a second transmission input shaft and a clutch device having a first clutch arrangement which is assigned to the first transmission input shaft and a second clutch arrangement which is assigned to the second transmission input shaft, for transmitting torque between the drive unit and the transmission, the clutch arrangements are embodied as multi-plate clutch assemblies, to which an operating fluid, in particular a cooling oil, for operation under the action of the operating fluid can be supplied through the intermediary of a pump assembly proposed that the pump arrangement or the Flusseinstelleinrichtung or / and a hydraulic actuating device for the clutch assemblies associated pump arrangement are operated in a circulation mode in which by circulation of operating fluid irrespective of a supply demand of operating medium to the clutch assemblies and independently of the actuation of the coupling means thermal energy in is entered, the operating medium, a bypass is unlockable to circulate the operating medium to the coupling assemblies past can and wherein a control device is applied for to address indizierendes event on an upcoming start of the motor vehicle and start the circulation operation in response to the indicated event. This invention proposal stems from the fact that energy is introduced into this by circulating liquid so that the liquid is heated. After the proposed invention is thus intended to heat the working fluid therethrough and thus reduce the drag torques in that the operating fluid is circulated by driving the respective pump assembly or Flusseinstelleinrichtung in recirculation mode and heats it. Preferably, a bypass is unlockable to circulate the operating medium to the clutch assemblies can pass, so even the drag torques are not increased by the circulation.

p0013A further development it is proposed that a control device is designed to address indizierendes event on a an upcoming start of the motor vehicle and take in response, the circulation mode. For example, when using an electric cooling oil / pressure oil pump of the invention "warm-up" already be initiated when the driver opens by remote control the vehicle and / or the driver's door is opened. One can also provide for the saving of electrical energy (approximately the starting an internal combustion engine to ensure) that the circulation operation is only initiated when the internal combustion engine is running.

p0014Generally it is proposed that a / the control unit is adapted to automatically circulating then initiate, if at least one positive condition fulfilled and / or at least one negative condition is not fulfilled. It is also generally suggested that a / the control unit is adapted to terminate the circulation mode automatically, if at least one positive condition fulfilled and / or at least one negative condition is not fulfilled.

p0015Depending on the design of the motor vehicle with respect to the low-temperature operation, it is conceivable that a driving off is only permitted when the working fluid (oil) a sufficiently high temperature or such viscosity has reached that proper switching is possible. It is proposed in particular that a / the control device is designed to enable a start of the drive unit in response to an instantaneous viscosity state of the working medium and to terminate.

p0016This proposal is of general interest, thus refers not only to the heating of the operating fluid by circulation, but specifically also to all other possibilities for heating the working fluid before driving.

p0017It is therefore for a motor vehicle, comprising a drivetrain, which has: a drive unit, a transmission with a first transmission input shaft and a second transmission input shaft and a clutch device having a first clutch arrangement which is assigned to the first transmission input shaft and a second clutch arrangement associated with the second transmission input shaft is assigned, for transmitting torque between the drive unit and the transmission, the clutch arrangements are embodied as multi-plate clutch assemblies, to which an operating fluid, in particular a cooling oil, for operation under the action of the operating fluid through the intermediary of a pump arrangement can be supplied, proposed that a control device is designed to release a start of the drive unit in response to an instantaneous viscosity state of the working medium and to terminate.

p0018Generally, the heating of the operating fluid by appropriate operation of the coupling device of particular interest appears. For this purpose it can be provided that a / the control device is adapted, by means of a preferably hydraulic actuator to operate the clutch assemblies and to operate in a warm-up mode at least one, preferably both clutch assembly with slip.

p0019In this context, in particular thought that the controller is adapted at least to have a clutch assembly with slip work when the vehicle against a braking a braking device and / or to operate the at least one coupling assembly in a moving vehicle with slip. A loop Leave a clutch assembly or clutch assemblies in gear against a braking device should preferably be held in a high gear, because here affects a relatively small drive torque at the wheels and the brake device so that a relatively small torque (braking torque) must apply to the vehicle to maintain or set a desired resultant driving torque.

p0020In connection with all the invention proposals and also independently of this, it is useful to provide preparatory and support measures to prepare for the shutdown of the motor vehicle and / or the gear engagement so that the drag torque problem is at least alleviated, and to search through specific measures the breakaway of the slats, so to promote or support the overcoming of adhesion torque.

p0021Thus, for the preparation of the linkage specifically proposed that a pump assembly or Flusseinstelleinrichtung be controlled by a / the control device to adjust an instantaneous operating fluid flow to the plate clutch assemblies, and that the control device is adapted to prepare throw-off of the motor vehicle or when turning off the motor vehicle with a disengaged clutch assemblies for a predetermined time interval to set an inflated operating fluid flow to push the plates of the clutch assemblies apart by means of the operating fluid flow. According to this proposed development is provided to the working fluid flow, in particular cooling oil flow, temporarily strong to lift the clutch assemblies for cooling thereof to push through this power the blades with the clutch assembly apart. This measure can advantageously be applied both when parking the motor vehicle with inlaid corridors and when parking the motor vehicle with designed speeds and is of general interest.

p0022Accordingly, according to a third main aspect of the invention for a motor vehicle, comprising a drivetrain, which has: a drive unit, a transmission with a first transmission input shaft and a second transmission input shaft and a clutch device having a first clutch arrangement which is assigned to the first transmission input shaft and a second clutch arrangement which is assigned to the second gearbox input shaft, for transmitting torque between the drive unit and the transmission, the clutch arrangements are embodied as multi-plate clutch assemblies which is an operating fluid, in particular a cooling oil, can be fed for operation under the action of the operating fluid through the intermediary of a pump assembly , proposed that the pump assembly or flow adjusting assembly is controllable by a control device in order to adjust an instantaneous operating fluid flow to the plate clutch assemblies, and that the control means is adapted to detect an upcoming parking the motor vehicle or shutting off of the motor vehicle and in preparation of the linkage or when parking in the disengaged clutch assemblies for a predetermined time interval to set an inflated operating fluid flow to push the plates of the clutch assemblies apart by means of the operating fluid flow.

p0023Preferably, the control means is adapted to adjust the excessive operating fluid flow as required, when at least one positive condition fulfilled and / or at least one negative condition is not fulfilled.

p0024A further advantageous measure is to bring before parking the vehicle, the drive unit briefly relatively high speeds (for example,> 2000U / min) to hurl through the resulting increased centrifugal forces the working fluid (cooling oil) from the clutch assemblies. It is specifically proposed that a / the control unit is adapted to operate to prepare throw-off of the motor vehicle and / or when turning off of the motor vehicle for a predetermined time interval in the disengaged clutch arrangements, the drive unit at an opposite an idling speed significantly higher rotational speed in order to carry centrifugal action remove operating fluid from the plates of the clutch assemblies.

p0025This proposal is both associated with a stopping of the motor vehicle with inlaid corridors as well as in connection with a parking the vehicle with designed courses advantageous and also of general interest.

p0026Accordingly, according to a fourth main aspect of the invention for a motor vehicle, comprising a drivetrain, which has: a drive unit, a transmission with a first transmission input shaft and a second transmission input shaft and a clutch device having a first clutch arrangement which is assigned to the first transmission input shaft and a second clutch arrangement which is assigned to the second gearbox input shaft, for transmitting torque between the drive unit and the transmission, the clutch arrangements are embodied as multi-plate clutch assemblies which is an operating fluid, in particular a cooling oil, can be fed for operation under the action of the operating fluid through the intermediary of a pump assembly , suggested that one of the drive unit associated control means is adapted to detect an upcoming parking the motor vehicle or shutting off of the motor vehicle and in preparation of the linkage or when parking for a predetermined time interval in the disengaged clutch arrangements, the drive unit at an opposite an idling speed significantly higher speed to operate in order to remove operating fluid by centrifugal action of the plates of the clutch assemblies.

p0027For a particularly effective free spin of the coupling arrangements, the control means may be advantageously adapted only to interrupt the supply of operating fluid to the clutch assemblies and then to operate for the predetermined time interval, the drive unit in relation to the idling rotational speed significantly higher speed.

p0028Further, the controller may be advantageous adapted as required, then operate the drive unit with respect to the idle speed significantly increased speed when at least met one positive condition or / and at least one negative condition is not met.

p0029To prepare the gear engagement or facilitate gear engagement is proposed that a / the control device is adapted for preparing an insertion of at least one gear ratio and / or the insertion of at least one gear ratio for a predetermined time interval at least a disengaged clutch arrangement and / or a maximum a gear used to operate the drive unit at an opposite an idling speed significantly higher speed to remove by centrifugal force operating fluid from the plates of the clutch assemblies. Thus, after starting the engine to support the gear engagement when no gear is engaged or has been, the engine speed can be increased to take advantage of the on the operation fluid (cooling oil) thus increased centrifugal force to freizuschleudern the disk pack and the disk sets, and thus the to reduce drag torque, so that the gear engagement is facilitated. This invention proposal is also of general interest.

p0030Accordingly, according to a fifth main aspect of the invention for a motor vehicle, comprising a drivetrain, which has: a drive unit, a transmission with a first transmission input shaft and a second transmission input shaft and a clutch device having a first clutch arrangement which is assigned to the first transmission input shaft and a second clutch arrangement which is assigned to the second gearbox input shaft, for transmitting torque between the drive unit and the transmission, the clutch arrangements are embodied as multi-plate clutch assemblies which is an operating fluid, in particular a cooling oil, can be fed for operation under the action of the operating fluid through the intermediary of a pump assembly , suggested that one of the drive unit associated control device is adapted to an upcoming insertion of the at least one transmission gear or an engagement of at least to detect a transmission gear and in preparation for the insertion and / or during insertion for a predetermined time interval in the disengaged clutch arrangements, the drive unit at a compared to an idle speed; significantly increased speed to remove by centrifugal force operating fluid from the plates of the clutch assemblies.

p0031It is especially thought to operate the drive unit with disengaged clutch assemblies and / or without gear used in relation to the idle speed significantly increased speed.

p0032A further development it is proposed that the control device is adapted to interrupt only the supply of operating fluid to the clutch assemblies and then to operate for the predetermined time interval, the drive unit in relation to the idle speed significantly increased speed. One can interpret the control device advantageously ensure, if necessary, then to operate the drive unit with respect to the idle speed significantly increased speed when at least one positive condition fulfilled and / or at least one negative condition is not met.

p0033To support the Losbrechens of the slats it is proposed that a / the control means is adapted to prepare for the engagement of a transmission gear with a stationary and / or running drive unit by means of a preferably hydraulic actuator, the clutch assemblies at least once, preferably several times in succession in the input and disengagement to press in order to achieve through mechanical tensioning of the clutch assemblies and / or displacement of the lamellae loosening of lamellae from each other, sticking the intermediary of operating fluid to each other or to support at least. It has been found that at about hydraulically actuated clutch assemblies with integrated in the coupling device hydraulic slave cylinders, clutch assemblies are braced by repeatedly pressing the piston of the clutch assemblies and that slight shifts of the fins occur. The manner of operation of the clutch assemblies play in connection with the proposal but ultimately not matter. The clutch assemblies can advantageously be both at a standstill and with the engine running. Even this operation may be sufficient to achieve a break-away torque of the slats. This operation can be advantageously carried out at a parked vehicle with inlaid corridors as well as in a car parked with courses designed vehicle before starting the engine, and further, if necessary, as required, after starting the engine. Proposal is also independent of the other aspects of the invention of interest.

p0034Accordingly, according to a sixth main aspect of the invention for a motor vehicle, comprising a drivetrain, which has: a drive unit, a transmission with a first transmission input shaft and a second transmission input shaft and a clutch device having a first clutch arrangement which is assigned to the first transmission input shaft and a second clutch arrangement which is assigned to the second gearbox input shaft, for transmitting torque between the drive unit and the transmission, the clutch arrangements are embodied as multi-plate clutch assemblies which is an operating fluid, in particular a cooling oil, can be fed for operation under the action of the operating fluid through the intermediary of a pump assembly wherein the clutch arrangements is assigned a control device which is adapted to the clutch arrangements to actuate by means of a preferably hydraulic actuating device, proposed that the control means is adapted to prepare for the engagement of a transmission gear with a stationary and / or running drive unit by means of the actuating device the clutch assemblies at least once, preferably several times in succession to actuate the inlet and disengagement direction in order to achieve through mechanical tensioning of the clutch assemblies and / or displacement of the lamellae loosening of lamellae from each other, sticking the intermediary of operating fluid to each other or to support at least.

p0035The control means may be adapted to actuate the clutch arrangements in the inlet and disengagement with respect to the release of the slats from one another as required, when at least one positive condition fulfilled and / or at least one negative condition is not fulfilled.

p0036The mutual release of the slats can also be achieved or at least encouraged that deliberately at running drive unit vibrations are introduced into the coupling device. For this purpose, especially proposed that a / the control means is adapted to selectively generate by a corresponding control of the running drive unit to the clutch device acting rotational irregularities or speed irregularities, especially torsional vibrations in the drive train to a loosening of lamellae from each other, which through the intermediary of operating fluid adhere to each other, to achieve or at least support. It is particularly advantageous if these speed irregularities, particularly vibrations are in the range of the natural frequencies of the clutch assemblies and / or the slats, so that it were picked specifically the mutually adhering slats. This proposed development is also of general interest.

p0037Accordingly, according to a seventh main aspect of the invention for a motor vehicle, comprising a drivetrain, which has: a drive unit, a transmission with a first transmission input shaft and a second transmission input shaft and a clutch device having a first clutch arrangement which is assigned to the first transmission input shaft and a second clutch arrangement which is assigned to the second gearbox input shaft, for transmitting torque between the drive unit and the transmission, the clutch arrangements are embodied as multi-plate clutch assemblies which is an operating fluid, in particular a cooling oil, can be fed for operation under the action of the operating fluid through the intermediary of a pump assembly , suggested that one of the drive unit associated control means is adapted, acting by corresponding control of the running drive unit to the coupling device speed irregularities, especially torsional vibrations, to produce selectively in the drive train to a loosening of lamellae from each other, sticking the intermediary of operating fluid to each other to achieve or at least support.

p0038The control means may be adapted to produce the force acting on the coupling device by means of speed irregularities of the drive unit, if necessary, if at least one positive condition fulfilled and / or at least one negative condition is not fulfilled.

p0039In the case of running an internal combustion engine drive unit, the control means may be adapted to produce the force acting on the clutch device by speed irregularities cylinder shutdowns and / or not uniform and / or alternating supply of the cylinder with fuel. The deliberately introduced vibrations can be achieved by cylinder shutdowns eg, it can be provided that are always the same, or alternatively different cylinders are deactivated. Furthermore, the cylinders are each supplied with different amounts of fuel to consciously generate rotational irregularities.

p0040The invention is further illustrated with reference to embodiments, on the one hand to perform various invention proposals after the various aspects of the invention directly by way of example and in which the various invention proposals after the various aspects of the invention can be implemented by the skilled person by routine use of its expertise ( associated for example by programming a one gear and / or a coupling device and / or a drive unit of the powertrain electronic control unit microprocessor-based), without it still requires an inventive step.<dl id="dl0001"><dt>Fig. 1</dt><dd>shows in Teilfig. 1a is a schematic, exemplary representation of a basic structure of a coupling system according to the invention with a wet-running double clutch and in Teilfig. 1 b is a schematic representation of a motor vehicle drive train of the invention together with an associated, the drive unit, the twin-clutch manual transmission and a load-addressing control means and associated actuators.</dd><dt>FIG. 2</dt><dd>shows a first embodiment of a coupling system according to the invention.</dd><dt>Fig. 3</dt><dd>shows the coupling system of FIG. 2 in combination with an associated gear.</dd><dt>Fig.4</dt><dd>shows a possible embodiment for a cooling-oil circuit of the transmission of FIG. 3. </dd><dt>Fig. 5</dt><dd>shows in the Teilfig. 5a) is a diagram indicating a typical dependence of the occurring in a multi-disk coupling arrangement drag torque at low temperatures as a function of the differential rotational speed, and in the Teilfig. 5b) a corresponding graph showing a typical course of the drag torque at very small differential speeds, including the breakaway torque in the case of composite adhesive lamellae.</dd><dt>Fig. 6</dt><dd>shows an example of a typical transmission synchronization of the prior art.</dd><dt>Fig. 7</dt><dd>shows schematically an automated dual-clutch transmission including the dual clutch upstream.</dd><dt>Fig. 8</dt><dd>shows an example of an inventive switching sequence for a train downshift.</dd></dl>

p0041Fig. 1 shows in Teilfig. 1a schematically illustrates a coupling system 200 having a wet dual clutch 202 having a first, radially outer clutch assembly 206 and a second, radially inner clutch assembly 204th When the clutch assemblies 204 and 206 is wet clutch assemblies, for example, wet-running multi-plate clutch assemblies, each having in a known manner at least one plate pack, which are radially arranged in the present embodiment above the other and each by an associated actuating piston of the dual clutch integrated hydraulic slave cylinder are operated. Examples of such dual clutches are z. B.<patcit id="pcit0002" dnum="DE10004179A1"><text>DE 100 04 179 A1</text></patcit> and disclosed in further published patent applications or patent applications.

p0042The coupling system 200 comprises two independent pumps, namely a first pump 208 and second pump 209, to which are preferably each driven by an electric motor 210 and 211th The first pump 208 provides pressure medium, in particular pressure oil, wherein a comparatively high pressure supply, which is sufficient to actuate the clutch arrangements 204 and 206 of the dual clutch 202nd To selectively actuating the clutch assemblies this, precisely the hydraulic slave cylinder, with an associated valve 214 and 216 are connected to the pump 208th The pump sucks pressure medium to from a reservoir 212th

p0043The second pump 209 provides a relatively high volume flow of cooling medium, in particular cooling oil ready, the 204 and 206 is used for cooling the clutch assemblies. The pump 209 sucks the cooling medium, optionally oil, to from a reservoir 222nd It should be noted that it is not necessarily that it is the reservoir 222 is a relative to the reservoir 212 separate reservoir.

p0044To be able to bring at low temperatures, the cooling oil is at operating temperature faster, 209 a change-over valve 230 and 232 provided on the discharge side of the pump 208 as well as on the delivery side of the pump. By means of the valves, a bypass line will be released to the reservoir 222 to 202 by introducing by circulating the working medium or print medium on the coupling device (dual clutch) heat in the oil and this heat it. The warm-up time to reach the operating temperature can thereby be significantly reduced and it can therefore relatively quickly a state can be achieved, in the in the clutch assemblies due to temperature 204 and 206 no disturbing drag torque due to too high viscosity occur (to great tenacity) more.

p0045Teilfig. 1 b shows a motor vehicle drive train of the invention with the dual clutch 202, associated therewith operating means 234 (for example from that shown in Fig. 2, the control valves 214 and 216 comprising Art), a means of an actuating means 236 automatically actuated powershift 330 with two coaxially extending transmission input shafts and an application running as a combustion engine drive unit 238. the above components are controlled directly or through the respectively assigned actuator which can be designated by an example as ECU and / or TCU controller 316th The controller 316, which can also be called control unit, may consist of several communicating part control units and receive signals from various sensors and actuators, such as a shift lever 452, the example, the shift positions P (parking mode), R (reverse mode) N (neutral mode) and D (forward driving mode), and from a brake pedal 450. a from the control device is operated braking system of the vehicle in Fig. 1 b designated by 454, and a controllable by the control device starter is in Fig. 1 b 456 designated.

p0046Fig. 2 shows an embodiment of a coupling system according to the invention of the basic structure shown in Fig. 1 in greater detail.

p0047According to FIG. 2, the cooling oil of the dual clutch 202 is fed through a heat exchanger 300, as this can lead to a marked increase in temperatures include the oil in the oil sump 212, for example in the event of a prolonged slip operation. Through the heat exchanger 300, the oil temperature is maintained at an adequate for cooling of the dual clutch temperature level. Since the cooling oil at low temperatures can be quite thick and because of the flow resistance of the heat exchanger 300 at particularly low temperatures might sufficient cooling oil would not reach the double-clutch or a could cause high oil pressure damage, a standing example spring-loaded bypass valve 302 provided that, when the cooling oil pressure downstream of the oil cooler 300 exceeds a predetermined pressure threshold, and opens by passes the cooling oil to the oil cooler 300 to the dual clutch.

p0048In the embodiment of Fig. 2, a pressurized gas cushion having Direction pressure oil storage 304 is installed in the clutch actuating pressure oil circuit, which is loaded by the pump 208 via a check valve 306 and through the valve 214 and the valve 216 to the actuation slave cylinders of the two clutch assemblies is connected 204 and the 206th The pressure oil reservoir 304 ensures a uniform pressure level, which in the case of formation of the pump 208 as a piston pump is particularly useful, and allows for the pump 208 is sufficient a pump with a particularly small delivery volume. The per unit time delivered by the pump 208b oil volume can therefore be smaller than the pressure oil volume required during a clutch actuation per unit time.

p0049The pressure oil circuit between the check valve 306 and the valves 214 and 216 is secured by a pressure relief valve 308 against an excessively high, possibly leading to damage pressure of the pressurized oil. Of 304 as determined by the fill state of the store pressure in this pressure oil circuit is detected by a pressure sensor 310th Further, the discharge side of the valves 214 and 216, a pressure sensor arrangement, for example, depending on a pressure sensor to be 311 and 313 for both valves, associated with that captures the other side of the valves ruling, acting on the hydraulic slave cylinder hydraulic pressures.

p0050Another pressure relief valve 312 ensures that the other side of the valves 214 and 216 ruling, acting on the hydraulic clutch actuator coupling devices pressure does not exceed a maximum value, for example, to also prevent damage. About two check valves 314 and 316 it is achieved that a pressure limiting valve is sufficient to monitor the operating pressure of the two hydraulic slave cylinders.

p0051To maintain the good controllability / controllability of the clutch actuation can 307 and 309 (for example, comprising a spring-loaded piston, a Metallbalgfeder or the like) to be connected in parallel to the two hydraulic slave cylinders of the couplers 204 and 206, a respective hydraulic dampers. By such hydraulic damper pressure peaks are damped in the hydraulic system.

p0052In the event that at low temperatures, so a high viscosity of the oil, the pressure of the cooling oil for cooling the clutch is not sufficient, for example because the hydrodynamic pump used for the pump 209 can not generate a sufficient pressure, is in the arrangement of Fig. 2, a valve 315 is provided, via which a small volume flow can be branched off from the pressure oil flow provided by the pump 208 to provide a kind of "emergency cooling" of the clutch arrangements, if this is necessary. Since the opening of the valve occurs 315 required solubilizing high viscosity of the cooling oil only at low temperatures at which anyway there is little cooling requirement for the dual clutch, is enough, a relatively small "Notkühlölstrom" from. This "emergency cooling" is, moreover, only as long as required until the temperature of the oil, and thus the viscosity of the oil sufficient to ensure a sufficient flow rate of the cooling oil pump 209th Instead of a valve 315 a so-called diaphragm or throttle or the like could be provided through which a constant small air flow is branched off from the pressure oil flow provided by the pump 208 in the coolant circuit. Is that the cooling oil only when needed branching valve 315 provided that pump 208 can be possibly operated shortly in an overload operation, to provide in the short time until the adequate heating of the oil sufficient cooling oil. Since it is only necessary for very short periods in the rule, the life of the pump 208 is not substantially shortened. To ensure independent of the operating condition of the pump 209 that flows from the pressure pump 208 supplied into the cooling cycle oil does not return to the oil sump 212, can 317 connected to the pump 209, a check valve in series, in particular downstream of the pump, be.

p0053Also in the example of FIG. 2, the bypass valve 232 is provided in order to adjust a recirculation mode at low temperatures, in which the pump 209 circulates the coolant oil to the dual clutch 202 over. One can run the valve also so that a portion of the already supplied by the pump 209 cooling oil flow is led to the dual clutch 202 and the other part is fed back via the bypass line to the oil sump 212th In order for a reduced coupling operation or driving operation of the drive train having a motor vehicle and in the recirculation is at least possible.

p0054FIG. 2 also shows an electronic control unit ECU (reference numeral 316), the control / regulating valves actuated in response to a respective command variable 214 and 216. It may further be provided that the control unit receives readings from various sensors such as the pressure sensor 310 and other pressure sensors (including possibly the sensors 311 and 313), and supplied from temperature sensors or temperature sensors. are envisaged in particular to one or more temperature sensors, which detects the temperature of clutch cooling oil circuit (pump 209, cooler 300 or bypass valve 302, coupler 202, sump 212). An appropriate, arranged for example in the clutch oil sump 212 and the temperature of the circuit encircling or present in the bottom oil sensor detecting 320 is shown schematically. The electronic control unit may further related to the time unit delivery volume of the pump 209 and / or a transmitted flow of arranged in the circulation flow rate adjusting valve (not shown) control or regulate, for example, based on the detected by the sensor 320 temperature signal. In this way, the temperature balance of the coupling device 202 and the clutch cooling oil circuit can be influenced. By adjusting the agitation level in the cooling circuit can be influenced on the cooling rate in the radiator 300 (larger or Kleiner ÄT the radiator) and it can turbulent flow conditions on the one hand or laminar flow conditions on the other hand can be exploited.

p0055For completeness, is still to be noted that the present with 322 and 324 designated components in Fig. 2 oil filter. Alternatively or additionally, the oil filter may be 208 or 209 provided on the discharge side of each pump. It will be appreciated that the electronic control unit 216 214 and 216 and the valves 232 and 315 is operated depending on the situation in addition to the control-regulating valves.

p0056To get to the start of the motor vehicle, especially at low ambient temperatures, the cooling oil, and thus the coupling device or dual clutch 202 to operating temperatures and in particular the viscosity of the cooling oil quickly reduce the extent that the system is fully operational, an electric oil-heating arrangement may be provided, for example, has at least one heating element 326 in the sump 212 and / or at least one in the suction of the pump 209, for example, in the filter 322, supplementary heater 327th Also, in the suction duct of the pump 208, for example, in the filter 224, at least one heating element may be integrated. As heating elements, for example, about 30 mm x 50 mm wide heating plates can be used which have a kind of heating coil on its surface and can supply a heating power of approximately 300 W z. B.. Other types of heating elements, for example, in the kind of glow plugs for diesel engines, can be used. Another possibility is to provide a thermal energy storage device, such as a so-called memory latency provide.

p0057By integrating at least one heating element in a respective intake section of the cooling oil pump 209 and / or the pressure oil pump 208 can selectively be heated actually pumped oil without forcibly the entire volume of oil has to be heated. Accordingly, electric power is saved. Further, it can be ensured that only preheated oil is pumped by the pump in question.

p0058Fig. 3 shows the coupling system of Fig. 2 (not all components are shown) in combination with a dual-clutch transmission 330. The preferably automated operable gear 330 have their own, compared with the cooling oil circuit of the coupling device 202 separate Kühlölkreisölauf, for example in Fig. 4 shown kind. a by a motor 211 'driven oil pump 209' sucks cooling oil from a reservoir (the transmission sump) 212 'to. The delivered cooling oil is normally supplied to a cooler 300 'to be cooled components of the transmission 330th To avoid excessive pressure in the cooling oil circulation at low temperatures, for example, pressure-actuated bypass valve 302 'is provided which has a radiator 300 when exceeding a pressure threshold' frees immediate bypass line. The gearbox cooling oil circuit corresponds to the extent the clutch cooling oil circuit according to FIG. 2 and 3. The cooler 300 'with the bypass line, as shown in Fig. 4, between the pump 209' and the transmission (possibly automatic transmission) be arranged 330th However, it is also conceivable that cooler and bypass circuit downstream of the gearbox or transmission machine. The gearbox cooling oil circuit, a temperature sensor to be 'assigned 320 that measures the temperature of the circulating cooling oil and provides corresponding measured values, for example, to the electronic control unit ECU of FIG. 2. According to FIG. 3 and 4, the temperature sensor 320 is positioned 'in the transmission sump 212'.

p0059Notwithstanding the foregoing, to Figures 3 and 4 can also provide a common and depending on the situation together switchable cooling oil circuit for the dual clutch and the gearbox.

p0060Instead of the pressure-actuated bypass valve 302 in the case of the clutch cooling oil circuit or 302 'in the case of the transmission cooling oil circuit, an electric operated valve, for example, a 3-2-way valve may be provided for depending on demand or according to a thermal management strategy (about for selectively achieving and Keep a setpoint operating) a radiator to release 300 immediate bypass line so that the cooling oil is guided to the radiator 300, 300 'by the dual clutch 202 or to be cooled transmission components, or to terminate this bypass line again.

p0061The dual clutch 202 can advantageously after starting the motor vehicle, for example in the case of low ambient temperatures, be operated with a defined slip in order to quickly heat the cooling oil to warm. The warming of the cooling oil is carried out by occurring on the fins in the slip operation friction. To avoid overheating of the relevant plate assembly or the dual clutch and achieve the desired heating of the cooling oil as quickly as possible, should ever a supplied example from the pump 209 flow of cooling oil flow during slippage operation. For further details of such a slippage operation which can take place both at a standstill and when the vehicle is on the content of the filed on 15.06.2001<patcit id="pcit0003" dnum="DE10128856"><text>German patent application no. 101 28 856.5</text></patcit> referenced. The disclosure of this German patent application is fully incorporated by reference into the disclosure of the present application.

p0062The occurring especially at low ambient temperatures in a car parked about outdoor automobile high viscosity of the cooling oil used may well cause significant problems. By at low temperatures (about oil temperatures less than 0 ° C) occurring increased viscosity of oil can in the multi-plate clutch assemblies very high drag torques occur (up to values ​​greater than 25 Nm) over at operating temperature (90 ° C) occurring drag torques for example less than 2 Nm. Further occur until about 50 Nm due to stuck together through located between the fins oil slats breakaway or Loslösmomente. In consequence of the high towing or breakaway torque can be virtually impossible an engagement of a gear, because conventional synchronizers of the transmission are not designed for overcoming such high moments. Can not insert transitions or turn, so it is impossible to move the vehicle.

p0063Fig. 5a shows a typical or exemplary curve of the drag torque occurring at low temperatures in the coupling device due to befindlichem between the slats cooling oil correspondingly high viscosity as a function of the differential speed Än between input side and output side of the respective clutch arrangement. Fig. 5b shows the breakaway torque occurring at low temperatures due to stuck together slats and the transition to the drag torque of Fig. 5a. For further details refer to the article "<nplcit id="ncit0001" npl-type="s"><text>Drag torques on wet-running multi-disc brakes "by N. Holzer and D. Frey, Friedrichshafen, as well as Matthes, Heidelberg, in VDI REPORTS 1323, Pages 469-489</text></nplcit> Development, Design and Marketing on 03 and 04.03.1997 in Fulda "couplings in drive systems '97" made due to a meeting of the VDI Society.

p0064Fig. 6 shows an example of a conventional single-cone Synchroniserung after system Borg Warner (ZF) with a needle bearing idler gear A, a clutch body B with shift gearing and friction cone, a main function carrier - synchronizer ring C with counter-cone and serration, a synchro-D with internal teeth for the mold flow to a transmission shaft and external toothing of the shift sleeve, a compression spring e, a ball pin F, a pressure piece G and H with a shift sleeve claws inner toothing. If one were to try to engage a gear when the motor vehicle and the engine not running, so it can happen that the engagement of the gear fails because the selector teeth of the coupling body of the respective Transitional Council coincides with the tooth flanks of the associated mating gear of the shift sleeve of the synchronizer so that the teeth can not come into driving engagement. The engagement of a gear is therefore only possible if the selector teeth of the coupling body strikes the interdental spaces of the associated mating gear. Thus it is in conventional design of the associated actuator is no real solution if you should remember to insert to avoid loading problem at low temperatures due not designed to overcome the drag torques Synchronsiereinrichtungen a starting gear in the motor vehicle is in the state not yet running drive unit.

p0065In Fig. 7, a dual clutch transmission 330 is schematically shown that seven gears, namely six forward gears G1, G2, G3, G4, G5 and G6, and a reverse gear R has. The forward gears is respectively a gear pair, consisting of a drive gear 400-1, 400-2, 400-3, 400-4, 400-5 and 400-6 and an output gear 402-1, 402-2, 402-3, 402 -4, 402-5 and 402-6, assigned. The reverse gear R in addition to a drive gear 400-R and an output gear 402-R comprises a rotation direction reversing end idler 404, which meshes with the drive gear 400 and the driven-R 402-R. The gears G2, G4 and G6 associated drive wheels are rotatably connected to a radially outer transmission input shaft 406 and the gears G1, G3, G5 and R associated drive wheels are rotatably connected to a radially inner transmission input shaft 408th The respective output gears are rotatably mounted on a transmission output shaft 410 and with this for shifting the gears via associated switching un d synchronizing 412a, 412b, 412c and 412d rotatably connected. The switching and Synchronsiervorrichtungen 412a, 412c and 412d are two-sided effect formed, ie that each alternative a is through these switchable from two aisles, in the case of the synchronizing device 412a of the first forward gear G1 or the reverse gear R, in the case of the synchronizing device 412c of the third forward gear G3 or the fifth forward gear G5 and in the case of Synchronsiervorrichtung 412d of the fourth forward gear G4 or the sixth forward gear G6. The synchronizing device 412b, however, is only one side effect is formed and used for switching only the second forward gear G2.

p0066As can be seen from the schematic figure, or mentioned above, the transmission input shafts 406 and 408 coaxially arranged to each other, and it is the odd-numbered gears G1, G3 and G5 and the reverse gear R of the centrally arranged gearbox input shaft 408 and the even-numbered gears G2, G4 and G6 associated with the form of a hollow shaft gearbox input shaft 406th The two input shafts are each provided with only one of the clutch assemblies 204 and 206 in connection, for example, the transmission input shaft 406 to the output side of the clutch assembly 206 and the transmission input shaft 208 to the output side of the clutch assembly 204. The input sides of the two clutch arrangements are each connected to the output shaft of the drive unit, for example, an internal combustion engine, in conjunction.

p0067During normal driving operation of the gear ratios is engaged and the clutch arrangement assigned to this closed. In a shift, first, a target gear, for example, the next higher or low forward gear, connected and then preferably the known per se Intersection circuit in which the drive torque is transferred from one to the other transmission input shaft to provide a tractive force interruption-free switching.

p0068In the illustrated embodiment, the dual-clutch transmission 330 is designed as an automated manual transmission. Given the shifting and synchronizing devices 412a is to 412d jewiels an example electromotive switching actuator 414a, 414b associated with 414c and 414d, which act on the respective switching and synchronizing, for example, by a non-positive and / or positive operating link. By switching actuators, the switching and synchronizing devices can be moved in the axial direction and to be entrusted with restoring forces, as indicated by the double arrows. At the driven wheels and the switching and synchronizing driver formations 416 and 418 are shown schematically, the contact for coupling the respective output gear with the transmission output shaft 410 in mutual engagement.

p0069The switching actuators are connected via associated control lines to the control device 316 and controllable by this. A rotational speed of the transmission output shaft and the transmission output shaft 410 can be detected by a speed sensor 420th It may furthermore a respective one of two associated Getriebeingangswellen and their speed detected rotational speed sensors 422 and 424 may be provided, so that the control device 316 optionally obtains information about all three speeds. Another alternatively or additionally be provided possibility is that the speed of the output shaft of the drive unit is detected by a control device connected to the speed sensor.

p0070To facilitate the insertion of gears in a car parked with designed courses motor vehicle, the actuation connections manufacturing, executed for example in the form of shift forks connecting and operating elements between the switching and synchronizing devices and the respective shift actuator are designed to be elastic, for example, with a respective Federabschnit 430th If when the motor vehicle and not the engine is running by a corresponding command from the controller 316 is a circuit actuator, for example, the contact module 414, moved in the direction of insertion of the first gear or reverse gear, the gear is either directly inserted, if the driver formations of the relevant driven wheel and the associated driver formations of the respective switching and synchronizing in mutual engagement occur (ie, for example, the teeth of one gear encounter between teeth of the other gear), or the gear is not engaged when the so-called driver formations do not occur in mutual engagement can.

p0071Is such an intervention is not possible (because the teeth of a gear hit the teeth of the other gear), so serving as a power storage spring brake 430 is tensioned. If now the starter is operated at open clutches, it is under the condition of low temperatures, so the occurrence of breakout and / or drag torque in the clutch arrangements, the clutch or the motor-side gears given a rotational movement, because the drive train due to the breakaway or drag torques is not completely disconnected from the engine in spite of open clutch assemblies. The gears on the transmission output side are, however, as a parking brake is engaged and / or the vehicle is unlocked with the parking brake. It is therefore a relative rotational movement between the drive wheels on the one hand and the associated switching and synchronizing it will entail in a relative rotational position in which the driver formations come into mutual engagement (because the teeth of one gear to the tooth spaces of the other tooth to meet). For an engagement of a gear in the event of a car parked with courses designed motor vehicle is possible even at low temperatures.

p0072Alternatively or additionally, the switching actuators can also be adapted for short periods to normal actuating forces applied vergößerte restoring forces, the switching and synchronizing would unduly burden in continuous operation, but under special circumstances (such as a high viscosity of the multi-plate clutch assemblies associated cooling oil due to low temperature) advantageously a gear engagement or gear changes allow. A certain reduction of the life of the switchgear and Synchroniservorrichtungen could take necessary into account, as those situations are rarely occur normally. Moreover, the controller 316 may be adapted to adjust the excessive actuation forces only for short time intervals and under certain conditions, so that in practice no significant shortening of the life of the switching and synchronizing will occur.

p0073The controller 316 may also include an operating mode in which the switching of an output gear to a target gear to the target gear assigned transmission input shaft not only by the target gear assigned switching and synchronizing, but also by another switching and synchronizing that for se is provided when switching to the same transmission input shaft assigned to be different from the target gear gear engaged. For example, for the preparation and insertion of the first gear G1 not only the switching and synchronizing device 412a but additionally also the switching and synchronizing to 412c is operated, so that these devices together the transmission input shaft 408 a rotational speed of at least approximating to that of the current vehicle speed, taking into account Getriebübersetzung in the target gear corresponds (in the example, the first course). Conversely, for inserting the third gear G3 or fifth gear G5 next to the switching and synchronizing 412c addition, the switching and synchronizing is 412 operated in this sense. The same applies to the Getriebeeingansgwelle 406 gears assigned G2, G4 and G6. It can in each case two switching and synchronizing (412b and 412d) or (412a and 412c) are operated simultaneously in this sense.

p0074However, it is to ensure that not accidentally the wrong gear is selected. This can for example be avoided by the control device 316 the speed of the respective transmission input shaft and the transmission output shaft 420 (and / or the output shaft of the drive unit), taking into account the gear ratios, particularly in the transmission ratio of not next gear, with each other and before reaching the synchronization point of the not next gear cancels the assigned on this not intended gear shift and Synchronsiervorrichtung acting operating forces, or at least sufficiently reduced.

p0075By appearing at the non-gear to be associated switching and synchronizing friction work can even at low temperatures despite occurring in the coupling device 202 drag torques a gear can be engaged or be switched from an initial gear to a target gear.

p0076The controller 316 is advantageously designed to simultaneously insert at least two passages through the switching actuators. It is particularly contemplated that a parking lock is achieved in that on the same transmission input shaft two gears are inserted.

p0077Advantageously, but a transition on the one transmission input shaft and at least one passage on the other transmission input shaft can also be inserted at least, and preferably at least one forward gear and the reverse gear are among the inlaid corridors. These transitions are preferably automatically inserted by the control device when the vehicle is parked. If you want to set off again, so it could be that big drag torques occur due to low outdoor temperatures in the coupling device, so that no transition can be inserted (unless that the above proposals are implemented). If, however, as suggested here, inserted the reverse gear on a transmission input shaft and at least one forward gear on the other transmission input shaft, so either the forward gear or the reverse gear can be activated to start by engaging a and Ausgekuppelthalten or disengaging the other clutch arrangement. For many situations it will also be sufficient if only one gear, such as the forward gear is engaged, preferably automatically by the control device 316th

p0078Apart from the aspect of the parking lock it makes perfect sense in other ways, at least one of the transmission input shaft, preferably on both transmission input shafts to insert several gears when the motor vehicle is parked. This allows namely to start a selection of several courses. There are then interpreted all the gears are not needed, for example, all forward gears up to a starting gear and reverse gear.

p0079To avoid due during engine cranking an uncontrolled movement of the motor vehicle at least an engaged gear and the drag torques or Losreismomente occurring at low temperatures in the coupling device, a security functionality of the controller 316 is preferably provided. The controller 316 may only allow, for example, to start the engine when the foot brake at the same time 450 (see. FIG. 1 b) is operated. Starting or not starting can be made dependent on the current position of the shift lever 452, for example, a start only in parking mode P are allowed.

p0080Furthermore, it is for safety reasons advantageous if the security functionality allows the lifting of the parking mode in which, for example, necessarily have a parking brake is activated, and the change in the reverse mode R or the forward driving mode D in spite of such pressure on the pedal 452 only if at the same time the foot brake 450 is actuated. This prevents that there is an uncontrolled movement of the motor vehicle when the parking lock designed respectively, is inserted in the case of not yet engaged gears, a forward starting gear or the reverse gear. Another possibility is that the cancellation of the park mode and - in the case of not yet inserted transitions - the engagement of a gear with an actuation of the vehicle brake system 454 is positively coupled. Despite not actuated brake pedal is then automatically ensured that the vehicle brakes are applied to prevent an uncontrolled movement of the vehicle.

p0081You can provide that, based on the drag torque occurring in the coupling device, a vehicle creep is already provided. For this purpose, the control means 316 have a corresponding creep functionality.

p0082Preferably, a compensation of the forces acting on the vehicle wheels clutch drag torque to zero or a creep or a peak hold is provided (in the case of a vehicle hill-hold function), namely, for example, by means of the vehicle braking system and / or by means of a concerted operation of the two clutch arrangements in the case that on the one clutch arrangement associated transmission input shaft and a forward gear is engaged on the other clutch arrangement associated transmission input shaft of the reverse gear. Generally speaking, an effective on the vehicle wheels driving torque due to clutch drag torques and / or clutch lamellae adhesive moments becomes zero or a desired value can be compensated by means of the vehicle brake system or by means of appropriate actuation of at least one of the clutch assemblies by the control unit 316, the vehicle braking system 454 and / or the coupling device 202 and the clutch assembly concerned correspondingly drives.

p0083Referring again to the state in the following, at the same time a forward gear and a reverse gear at the same time are inserted. Preferably, these passages may remain inserted during start and during the subsequent driving of the motor vehicle, and it can be changed by opposite actuation of the two clutch arrangements between the forward speed and the reverse gear, without the need for an operation of the transmission. As long as the reverse gear is engaged, it should be provided by a safety functionality of the control means 316 that a maximum vehicle speed is not exceeded. One can also provide for an automatic disengagement of the reverse gear in the event that the vehicle speed exceeds a threshold value.

p0084The controller 316 may advantageously comprise an active Synchronsiermodus in which by corresponding control of the motor (generally the drive unit) and / or the rotational speed of the target gear assigned to the transmission input shaft at least approximated by corresponding actuation of the clutch arrangements the synchronization ratio of the target gear, preferably the rotational speed of transmission input shaft is brought to the synchronous ratio of the target gear, only to facilitate or permit the engagement of the target gear. The switching and synchronizing devices are then spared accordingly, and it does not need necessarily to the use of multiple stem and synchronizing devices simultaneously, and it can also be on the engagement of a gear by utilizing a bias of the operating connection between the relevant switching and synchronizing and the associated to dispense switching actuator. A traction interruption during switching is to take in this active Synchronsiermodus in purchasing.

p0085Fig. 8 shows an example of a shifting sequence in a train-downshift, allowing a zugkaftunterbrechungsfreies back-switching without excessive friction work must be made to the shaft and Synchronsiervorrichtungen for synchronization of the target gear associated transmission input shaft, even with large drag torques in the Kupplunsgeinrichtung.

p0086. The Figure 8 on the following assumptions and the following nomenclature is based:

p00871 and 2, it is referred to the transmission input shafts 1 and 2, couplers 1 and 2 and gears. The transmission input shaft 1, the transmission input shaft 406 and the gearbox input shaft 2 can be the transmission input shaft 408, or vice versa. Accordingly, the clutch 1 the clutch assembly 204 and the clutch 2 of the clutch assembly 206 may correspond to, or vice versa. Run 1 is the transmission input shaft 1 gear assigned (the starting gear) and gear 2 is a transmission input shaft 2 associated gear (the target gear). It is connected in a train-operating state of a larger, the transmission input shaft 1 associated gear 1 to a smaller, the transmission input shaft 2 associated gear. 2

p0088When Switching train rear-engine supplies a positive torque to the transmission. This torque is transmitted through the transmission input shaft. 1 The coupling 1 is connected to the transmission input shaft 1, the coupling 2 is connected to the transmission input shaft second In the initial state, the clutch 1 is completely closed and is thus in overpressure. The clutch 2 is open at the example shown in the initial state. The transmission input shaft 1 thus rotates in the initial state with the engine speed. On the transmission input shaft 1, a gear is engaged, so that the power flow between the transmission input shaft 1 and the transmission output shaft is made.

p0089A preferred five switching phases comprehensive switching sequence is illustrated in Fig. 8 schematically. The phases are indicated in Fig. 8 by Arabic numerals 1 to 5 in circles and are addressed as phases I to V below. Possible variants and embodiments of the switching phases are shown in the FIG. By dashed lines. To differentiate the various curves and curve sections are provided with the symbols N_Mo for the engine speed N_G1 for the rotational speed of the transmission input shaft 1, N_G2 for the rotational speed of the transmission input shaft 2, M_Mo for the engine torque, M_K1 for the torque of clutch 1 and M_K2 provided for the torque of the clutch. 2 Any difference between the positive longitudinal acceleration (see. Lowermost part diagram) of the motor vehicle resultant, the change in vehicle speed representing additional contribution to the change in speed is not considered in the partial diagram of the speeds. Furthermore, for simplicity, assume a per se (without active intervention in the engine management system) on the engine speed remains constant engine torque. The switching operation counted from the beginning of the switching phase I until the end of the switching phase V may, for example, about 0.5 s to 1 s take.

p0090If the clutch assembly 2 at the beginning also completely closed in derogation from the above assumptions made and the representation in the diagram in Fig. 8, so this could be fully opened to initiate the shift in phase I.

p0091In Phase II, the clutch torque of clutch 1, M is_K1, Lowered to the valid in Phase I of the engine torque. The driving torque of the engine is increased and the clutch 2 is slightly indented, so that now the engine torque is greater than the torque of clutch 1, so that clutch slip occurs and the engine speed increases until the end of Phase II a speed greater than the synchronous speed of the target gear is achieved. 2 By slight engagement of the clutch 2, the transmission input shaft 2 is accelerated, so that the speed of the synchronous speed of the target gear approaching. At the end of Phase II of the target gear (gear 2) is inserted so that the participation of the target gear assigned Synchronsiervorrichtung the transmission, the transmission input shaft 2 reaches the synchronous speed of the target gear and it thus comes to engagement of the target gear.

p0092In Phase III of the selected engine speed is lowered to the rotational speed of the transmission input shaft 2, the engine torque return to the original moment in order to prevent a further increase in the engine speed after reaching. The clutch 1 is slipping, and a selected slip speed between the transmission input shaft 1 and the engine speed is controlled by means of the clutch. 1 The clutch 2 is closed controlled. Thereby a controlled opening of the clutch 1 is triggered, because the previously selected slip speed can be kept constant only if the sum of the moments that order of the two clutches on the transmission input shafts and - through the intermediary of the transmission - is transmitted to the transmission output shaft, constant equal to the selected engine torque is. The clutch 2 takes over more and more engine torque until clutch 1 is completely open. The clutch 2 can now transmit the entire engine torque and will not be closed. Instead of a controlled closure of the coupling 2 and a controlled opening of the clutch 1 could also provide a controlled opening of the clutch 1 and a controlled closing of the clutch. 2

p0093In phase IV, the engine speed is pulled down to the speed of the gearbox input shaft 2 by lowering the engine torque by the clutch torque. In Phase V, the clutch II is then completely closed. The clutch 1 can also be concluded that the increase of the speed N._G1 the transmission input shaft 1 leads to the level of the transmission input shaft second The engine torque is reduced during the switching sequence shown in the diagram to its original value already at the end of Phase IV.

p0094In Phase II, is shown yet a variant, according to which the torque of the clutch 1 is not completely reduced to the value of the initial motor torque to avoid an undesirable negative intermediate acceleration operation of the vehicle due to the acceleration of the transmission input shaft second Further, one can increase in Phase V, the engine torque to a value above the initial value, to compensate the acceleration energy required for the acceleration of the transmission input shaft the first

p0095This can be achieved that the entire acceleration course monotonous runs during the coupling procedure without Zwischenverzögerungs- or intermediate accelerations by the initial engine torque by means of the transmission input shafts discharged into the transmission and transmitted in accordance with the gear ratios in the source and target gear to the transmission output shaft at all times. On the transmission output shaft, a substantially constant lasting (phases I, II, IV, V) or monotone is maintains it at any time (preferably strictly monotonically, eg linearly) rising (phase III) driving torque.

p0096According to a shifting sequence, as suggested in Fig. 8 by way of example, a downshift is even at low temperatures or viscous cooling oil without significant burden of synchronizing possible to dispense with the load shifting without interruption of traction without.

p0097During an upshift, the target gear the associated transmission input shaft synchronous speed level is below that of the old passage. Is the target gear associated clutch open so can means are due to drag torque of the transmission, the speed of the target gear associated transmission input shaft between zero and the new synchronous speed of a separate braking device or / and. You can then bring by closing the target gear clutch assigned to the target gear associated transmission input shaft to the new synchronous speed to allow a gear engagement or facilitate. On the load shifting without interruption of traction it needs not be waived.

p0098The foregoing, in the mastery of the problems associated with drag torques in the coupling device at low temperatures targeting measures are under normal operating conditions is not necessarily longer necessary. It can therefore be provided that the control device 316 automatically a normal shift and clutch operation frees with free gear selection. For this purpose, the controller may receive from one example, the temperature of the cooling oil temperature sensor measuring a temperature signal and compare this with a threshold. If necessary, may consist of the measured temperature, the viscosity of the cooling oil to be determined, and these are compared with a predetermined threshold value. The controller may also be adapted for other measurements, if necessary temperature values ​​close to be considered for drag torques temperature, for example, based on a temperature model.

p0099To actively reduce drag torque control means (2, see Fig..) 316 may have a functionality that is used, the pump 209 to control so that only the amount of cooling oil is supplied to the clutch assemblies, as currently required, for example with regard to a in the coupling device power loss occurring and / or with regard to a lubrication demand on the plates. If necessary, , the cooling oil flow be interrupted completely to the clutch assemblies, if not currently supply needed.

p0100One may also provide that the controller is adapted to only enable starting of the engine when the viscosity of the refrigerator oil does not exceed a maximum value or the temperature of the cooling oil is not below a critical value. This measure is particularly in connection with mentioned here measures of interest, which enable a heating of the cooling oil irrespective of the running of the engine (see FIG. Heaters 322, 324 and the recirculation mode in connection with the valve 232). One can also provide that the parking of the vehicle is prepared so be that when re-starting the motor vehicle, the drag torques and breakaway occurring in the coupling device is minimized and ideally even largely avoided. So the controller can be adapted to an upcoming shutdown of the motor vehicle or a stopping of the same can be seen (the control device can for this purpose, for example, responsive to an adjustment of the shift lever 452 into the position P), and in response to this by stopping by disengaging the clutch assemblies for a certain time to set an excessive cooling oil pressure or an excessively high cooling oil flow to the clutch arrangements, to press the plates of the clutch assemblies apart, thus separating the outer plates and the inner plates of each other. This preferably takes place fully automatically by appropriate driving of the pump 209 by the control device 316. Alternatively or additionally, even after disengagement of the clutch arrangements, the drive unit are driven by the control device 316 in such a way in response to the detection of an impending throw-off of the motor vehicle or of the linkage, that the drive unit for a period of time running at a relative to the idling rotational speed significantly higher speed, so that the cooling oil from the plate packs is thrown radially outward by centrifugal action. For this purpose, the cooling oil flow is interrupted to the disk packs preferably before.

p0101The operation of the drive unit with disengaged clutch assemblies with respect to the idle speed significantly increased speed is also in preparation for an insertion of at least one transmission gear advantageous because the drag torques will be the smaller, the less cooling oil is located between the slats. Therefore, the control device 316 is preferably also designed to detect the engagement of a gear or the wish that a gear is engaged, and to control the drive unit with disengaged clutch assemblies accordingly. For example, the controller 316 responsive to an adjustment of the shift lever 452 in the position R or D and actually engage the gear in question only after the proposed spin up the drive unit.

p0102It has been found that also by operation of the clutch assemblies even loosening of each adhesive lamellae can be achieved and this loosening may be at least supported. This beneficial effect is due to occur in the course of clutch actuation mechanical tensioning of the clutch assemblies and the displacement of the slats in the operation. The controller 316 is preferably adapted to respond to the gear engagement request or the engagement of the gear and at least once, preferably several times to operate before shifting the engine or before the completion of the loading operation, the clutch assemblies successively in the input and disengagement to the issues raised achieve useful effect.

p0103It has also been found that also cause the clutch means acting speed irregularities, such as torsional vibrations, loosening of adjacent adhering slats or at least support. The controller 316 is therefore preferably adapted to the drive unit, in particular the internal combustion engine to drive such that, when running drive unit such speed irregularities occur. For example, shut down in an internal combustion engine cylinder or cylinders are supplied with fuel or alternately mixed.

p0104It proposes, among other measures to control or reduce occurring in a lamellar multi-clutch device drag torque due to temperature-related increased viscosity or tenacity of the blades supplied in operating working liquid to produce a startup of a motor vehicle or the operation of the motor vehicle even when low temperatures allow.