[Ö01 ] DRIVE TRAIN OF A MOTOR VEHICLE
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[4] The invervtion concerns a drive train of a motor vehlcle accordlng to the preamble of Claim 1.
[5]
[6] For a long time vehides have been known which are equipped with a coasting function in order to reduce fuel consumptlon. This operates in such manner that when the driver throtties down, the driving internal combustion engine is disconnected from the driven vehlcle wheels by disengas^ng a clutch in the drive train. The speed of the combustion engine can then be reduced to an idiing speed so that fuel is saved. To reduce the consumption stiN more, It is also known, in such thrust Operation phases of the motor vehkde with the drive power disconnected, to cut off the supply of ftiel to the combustion engine compietely although, in such a case, more effort is needed for the Operation of auxUiary aggregates. In both these operating modes, however, the braking action of the combu8tk>n engine, during thmst operation of the vehtele, is not available.
[7] For those famHiar with the sut^ct, it is obvk}U8 that corresponding to the operating modes for the combustbn engine, when driving downhill, the speed of the motor vehtele will increase steadily and, In the atoence of an engine braking action. this can only be prevented by actuating a Service brake or an additbnal brake (retaider). In passenger motor vehtoles, usu^ only a Service brake assodated with the wheels is available so that when such vehides are driving down steep hills, thrust operatbn phases with the drive power disconnected are usually avoktod.
[8] Further, in the Type FH t2 Volvo® goods vehide a drive train is known with a drive motor in the form of an internal combustk>n engine with a torque Converter made as an automatic spiitter transmission with 12 fonward gears with an actuator de\^ce to be actuated manuaHy in the fomn of an accelerator pedal for a power control eienrant (for example, a fuel injection pump) the drive motor, and with a manual(y actuated preselector element in the form of a transmission gear ränge selector lever, located next to the driver's seat, and with a maruially operated actuator in the form of a brake pedai for actuating a service brake which decelerates the driving speed of the vehicle.
[9] An electronic control unit, associated with the drive train detects a condition In which no drive power Is needed or an engine brake is not engaged; whether an automatic speed control unit is engaged: whether the transmission Is In automatic mode, and whether one of the fooA^rd gears 7 to 12 Is engaged. If all these conditlons exist simultaneously, the splltter transmission Is automatically shifted to neufral so that the torque-transmitüng actkMi, between the combustion engine and the driven wheeis, is interrupted.
[10] To overcome the downhill driving problem mentioned earlier, this known coasting functk>n is immediately suppressed by re-estabHshing the torque flow in the drive traln when either the brake pedal or the accelerator pedal is actuated or when the engine brake is engaged.
[11] In addition, in the unpublished patent apptteation DE 10 2005 003 608.2, a method is proposed for operating the drive train of a vehicle, which comprises a drive motor, for example an internal combustion engine, and a torque Converter, in the fonn of an automatic transmission or an autonuited shift transmission; with a manually operated actuator device for a power control element of the drive motor; with a manually operated preselector element for an operating range of the torque Converter or transmission; with a manually operated control elenrtent to actuate a brake that decelerates the driving speed of the vehide. and with an electronic control unit for reoeiving. processing and emitting signals and data of the drive train and/or of the vehicle. Furthenmore, a freewheel device with a coasting function is associated with thIs drive train.
In Order to be able quickly and flexibly. between the condltions "coasting eftect pennitted" and "coasting effect blocked" by acbjatlng the actuator device for the power control element or by actuating the control element that acts on the brake, the freewheel device is associated with the drive train In such a manner that:
a) in ^^ Operation when the actuator element forthe power controi element
not been actuated, the coasting function is at first permitted, and
b) witen the controi element for reducing the driving speed is then actuated, the coasting function is biociced, and
c) when the coasting function in thrust operation shouid be permitted again, this is done by operating the actuator device of the power controi eiement.
[13] Furthemfiofe, additionai braltes in the practice are Icnown, in pailkndar hydrodynamic v eiectrodynamic retarders, wiiich are mainiy used in commerdai vehicies and which serve to reiieve the ioad on the service brakes associated with the wlie^, in that besides the conventionai engine braice they have an additional braicing action as the result of retarder-intemai flukl friction er the produotion of electric eddy currents. For tiiis, a preselec^or eiement, for examfirie in the form of an operating lever, conveys the driver's braicing power demand in that, starting from a zero positkvi, the braicing resistance increases as tiie movement of the operating iever is increased or repeated. in combinsrtion wnth an eiecbnonic controi unit, the r^rder can be acbiated accordingiy.
[14] f=teganAessoftheat)ove,asalreadymenti^ng, processing and emitting signals and data of the drive tiBln and/or of the motor vehicle.
[19] At ttiis point, it should be made clear that the temr) "torque Converter" used includes any devices such ttiat the torque, delivered by the drive engine. can be changed and passed on. Thus, the term explicitly includes transmissions of any design.
[20] In this drive train, in order to achieve the stated ot^ective, it is now additionally provided that the preseiector element of the additbnal brake is connected by contrc^ technokigy means to the elec^nic control unit in a such manner that starting from a zero posttion "0", it can be actuated manualiy both in a diredion "1* for ^gnaliing ttie selection of a braking resistance of the additional brake, and also in another directton "II" for Signalling the ac^ation of a drive- power-off rotling or coasär^ operatton mode of the motor vmhide in the sense that the drive torque delivered by the drive engine is discorinected.
[021 ] By virtue of this measure, the preseiector eiement for the additional brake,
known in itself, is extended by a further setectk>n optk>n, namely. the option of activating a drive-power-off rolling or coasting operating mode of the motor vehicle in the sense that the drive torque of the drive engine is disconnected, preferably by opening a dutch in the drive train. For this. to adivate the rolling or coasting operating mode, the actuatton device of the pr^ielectcM^ element is nrK>ved from a zero Position in anotiier direction. preferably the opposite direction, to the actuatton directton for seiecting the braking resistance of the addittonal brake.
^^22] In ttiat case. the respective actuation direc^ions of the preseiector eiement
are logically comprehensible to the driver, since the activation of the rolling or coasting operating mode can also mean interrupting a braking torque of the drive engine, whioh Is logically opposed to applying a braking torque by way of ttie additlonal brake.
[23] In a particularly advantageous way, the two aduation modes in question are integrated in a Single, already existing preseiector eiement, whereby an additbnal actuating eiement for activating the drive-power-off roUIng or coasting operating mode and the resulting cost-increasing complexity, are avokled.
A(xx>rding to a particularly advantageous design feature of the invention, the preseiector eiement for the additlonal brake and the roiUng or coasting operating mode is made as a preseiector eiement which automatically springs back, at least from the position for activating the rolling or coasting mode In the sense of disconnecting the drive torque of the drive engine. to Its zero or rest posltbn. Accordingly, Uie roHing or coasting mode activation position is not ratcheted so that when its actuatton is no longer needed, the preseiector eiement can spring back again automatically to its zero or rest positton, for example under the force of a spring.
[25] Advantageousiy, this provides the prerequisites for beginning to terminate a set rolling or coasting operating mode of the nrator vehlde by operating the actustor devk^e for the power control eiement of the drive engine; the preseiector eiement lor seiecting a defined braking resistance of the additional brake; the control eiement for actuating a brake that decelerates the driving speed of the motor vehicie and/or as a functbn of other operating and/or other driving conditk>ns of the motc»-vehk:le, such as the current driving speed; the temperature of the drive engine and/or that of any fluid necessary for the fünction of a retarder; the currently engaged torque Converter or transmission gean a measured or caicutated drive torque; the current determined distance and/or speed values of other vehides and/or suchHke, but without reaching or remalning in an inconslstent actuatbn conditkm of the preseiector eiement once the rolling or coasting operating mode has come to an end.
^26] In addition, H is provided that the roHing or coasting operation of the motor
vehide is enabied by at least one freewheel device in the drive train, for exampie a dutcli mechanism, to disconnect the driven vehide v^els from the drive angine.
[027] Finally, it is proposed that the preseiector element of the additional brake is made in the nnanner of a pivoting lever, a rotating lever or a pull/push lever.
{028]
[29] To darify the invention the description of a drawing is given below. FIGS. 1 to 3 Show sdietnaticaliy represented exann^^s of three possible embodiments of the preselec^ etement for ^e additional brake described above.
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[34] Accordir^ to FIG. 1, a preseledor element 1 crf the additional brake (not shown here) arran{^ in a drive train of the niotor vehide, known in itself (not iiiustrated further), is made as a pivoting le\^ 1 a with a knob 2. In its starting Position, the pivoting lever 1a is at a zero or a rest positk>n designated by "0" and it can be swiveHed in two different actuation directions "1" and "II".
[35] As can be seen in this case, the two actuation directkms "!" and "II" are preferably exactiy oppostte one another. However, other actuatksn dlrectk>n8 "I" and "It", different from one another, are also possible (not iiiustrated further) and are thus covered by the inver^on.
[36] According to this exampie embodiment, the actuatksn directkm "1" is associated with the aeiectk>n of a defined braking resis^uioe to be applied by the addittonal brake, such that as the swivel angle of the pivoting lever 1a is increased, the braking resistarK» increases.
In contrast, the actuation direction "M" relates to activatkm of the roMing or coa^ng operating mode (rf the motor vehtete, the dout^ arrow being intended to
^ indicate that at least once the rolling or coasting mode has been actuated or put into Operation, the pivoting lever 1a automatically sphngs back to its initial or zero Position.
[38] Ttie pivoting lever is electricaliy connected to a control unit known in itself (not shown liere), wiiich generates corresponding control signals either to set the selected braking resistance of the additional brake or to activate the rolling or coasting Operation of the motor vehicie, for instance by opening a dutch in the drive train.
[39] When a rolling or coasting operating mode of the niotor vehicle has been chosen, this is preferably temiinated by operating an actuator device for the power control element of the drive engine, the preselector element 1 or pivoting lever 1a in the direction for seiecting a defined braking resistance of the additional brake, a control element for actuating a brake that decelerates the driving speed of the motor vehicle, and/or as a function of other operating and/or driving conditions of the motor vehicle. such as its cun-ent driving speed, the temperature of the drive engine and/or any flukl needed for the function of a retarder, the gear cunrently engaged in the torque Converter or transmission, a measured or caiculated drive torque, the cunrently detemnined distance and/or speed values of other vehides, and/or suchlike. For this, by virtue of its autonomous restoration, the preselector element 1 or pivoting lever 1a for the additional brake is already in its zero or rest Position and is avails^le for a subsequent actuatton.
[40] The example embodiment, shown in FIG. 2, differs from the example embodiment described above, only in that instead of a pivoting lever 1 a, a rotating lever 1bIsused. Incontrast,inFIG.3,apuH/pushleverlcIsprovided. Heretoo, the two ac^ation functions in question are advantageously inte^ted in the Single preselector element 1 already present in the vehkde. Although the actuatton directions T and "II" for activating the respective a^iBgate reactions are dlfferent, the vehlde operation modes assodated with them, such as coasting operatk>n or additional brake actuatk>n, In particular retarder braking operation, are exactiy the same for all three embodiments.
Referenq&f^umerais
1 preselector element 1a pivoting lever
1b rotating lever 1c puS/push fever
2 knob

CLAIMS
1. A drive train of a motor vehicle, with a drive engine, a torque Converter, an anal brake is conrtected by controi technology means to the electronic controi unit in such manner that starting from a zero position "0", it can be achiated manually both in a direc^on "1" for Signalling the selactbn of a braking resistance of the additional brake, and also in another direction "II" for signalling the activation of a drive-power-off roliing or coasting Operation mode of the motor vehicle in the sense that ttie drive torque delivered by the drive engine is disconnected.
2. The drive train according to Claim 1, characterized in that the preseiector element (1) of the additional brake te made as a pres^ctor element (t) that springs back automatically at least frcuD tts positbn for activating the roliing or coasting operating mode of the motor vehicle, to its zero positton.
3. The drive train according to Claims 1 or 2, diaracterized in that when a roliing or coastirig operating mode of the inctor vehide has been inttiated, it can be termlnated by operating the actuator device for the po\M»r contnal element of the drive engine. the preseiector element (1) for selecting a defined braking resistance of the additk)nal brake, the controi element for actuating a brake that decelerates tfie driving speed of the motor vehide, and/or as a function of other operating and/or other driving condttkms of the motor vehtele. such as the current driving speed, the temperature of the drive engine and/or that of any flukJ necessary for the functk>n of a retarder, the currently engaged torque converter or transmisston
gear, a measured or caiculated drive torque, the current detarmined distance and/or speed vaiues of other vehicles, and/or suchlike.
4. The drive train acx»rding to at least one of daims 1 to 3, charaderlzed in thät the roliing or coasting operation is enabied hy at least one freewhesi device, such äs a clutch mechanism which disconnects the driven vehide wheels from the drive engine.
5. The drive train according to at least one of daims 1 to 4, characterized in that ttie preseiector eiement {1) of the additional brake is nnade as an operating lever in the manner of a pivoting lever (1a), a rotating lever (1b), or a pull/push lever(lc).