DE102018203531A1 - Method for a drive train of a motor vehicle - Google Patents

Abstract

A method is proposed for a drive train (10) of a motor vehicle having an electric machine (22) and a variable speed transmission (11), which has an input shaft (61), an output shaft (91) and a plurality of gear stages (71) by means of clutches (81) on and be interpreted, and with a control device (15) for controlling the drive train (10), wherein the electric machine (22) via a translation stage (i1, i2, i3, i4) coupled to a transmission shaft or by means of a coupling device (59) can be coupled, wherein an instantaneous speed and / or a momentary direction of rotation of the electric machine via an evaluation of phase signals of the electric machine (22) or via a sensor (41a, 41b, 41c, 41d) is determined, wherein the control device (15) a current speed and / or a current direction of rotation of the transmission shaft (31,51,61,91) taking into account the current speed and / or the current Drehrichtu ng of the electric machine (22) and taking into account a transmission ratio of the gear ratio (i1, i2, i3, i4) calculated.

Description

The present invention relates to a method for a drive train of a motor vehicle having an electric machine and a step-change transmission, which has an input shaft, an output shaft and a plurality of gear stages, which can be engaged and disengaged by means of clutches, and with a control device for controlling the drive train, wherein the electric machine via a translation stage ( i1 . i2 . i3 . i4 ) is coupled to a transmission shaft or coupled by means of a coupling device, wherein a momentary speed and / or a momentary direction of rotation of the electric machine is determined by an evaluation of phase signals of the electric machine or via a sensor.

Furthermore, the present invention relates to a method for a drive train of a motor vehicle with an electric machine and a variable speed transmission having an input shaft, an output shaft and a plurality of gear stages, which are switched on and interpretable by means of respective clutches, and with a control device for controlling the Powertrain, wherein the electric machine is coupled via a transmission ratio with a transmission shaft or coupled by means of a coupling device, wherein the transmission shaft has a sensor to determine a current speed and / or a current direction of rotation of the transmission shaft.

The prior art, drive trains, comprising a variable speed transmission with an input and output shaft, recently known. Gearshift stages can be engaged via synchronous clutches, so that an input shaft driven by a drive motor and an output shaft are coupled together and form a transmission stage. The output shaft is in turn coupled to the output, ie the differential, in order to forward the drive power to the two drive wheels of the motor vehicle. The powertrain is controlled either manually by the driver (manual gearbox) or automated (automated manual or dual-clutch gearbox). In both cases, however, a control device is provided, by means of which transmission components, such as cooling components, synchronous clutches or the starting clutch are controlled.

In addition, a hybridization of a drive train has become known in which an electric machine is coupled to the drive train and this electric machine provides drive power for purely electrical operation or in combination with another drive motor, such as an internal combustion engine. The connection of the electric machine to the drive train can take place at different positions. Thus, the connection in the power flow direction before the variable speed transmission, ie between the engine and a starting clutch of the variable speed transmission is possible. The connection to a clutch input side or to a crankshaft has proved to be particularly advantageous. In addition, it is possible to connect the electric machine to the input shaft, to the output shaft or to the differential, preferably when the electric machine is aligned parallel to the stepped change gear.

Furthermore, it has become known to provide a translation stage in the power flow between the electric machine and the drive train. Such a design provides a traction drive or at least one gear stage in order to bring about a speed reduction.

The provision of the desired driving comfort of a drive train of the type mentioned by the customer requires a large amount of data to be processed and an increased data transfer between the individual transmission components and the control unit. Thus, the controller is not only designed to control switching operations. The monitoring of safety-relevant components must also be supported by the control device, in that, under certain conditions, relevant components are actively controlled or regulated. Exceeding a temperature threshold of a component, e.g. the clutch leads, if necessary. To increase the clutch supplied cooling fluid.

Also, monitoring rotational speeds of shafts, e.g. the input and output shafts, using speed sensors is a common practice to detect fault conditions, in particular fault conditions during a gear change.

In addition, the monitoring of directions of rotation of waves, e.g. the input and output shafts, known by means of rotational direction sensors or speed sensors extended by this function, so that the control unit in the event of a roll back d. Motor vehicle can intervene on a slope accordingly.

Furthermore, the prior art is known to automatically cancel the gear change as soon as the input shaft to be synchronized can not insert the desired gear before exceeding a predetermined time, then insert another gear. Also, in the presence of excessive rotational speed difference of the input and output shafts a gear change can be prevented by the control device to protect the friction linings of the synchronous clutches from wear and overheating.

Speed or direction of rotation sensors may correspond to commercially available Hall effect, inductive, oscillatory, magnetoresistive or vortex sensor and are in the drive train u.a. arranged on the crankshaft, the input shaft, the output shaft. In hybridized transmissions, a speed sensor is also found on the rotor shaft of an electric drive machine to determine the speed of the electric machine. Or the instantaneous speed is calculated from the evaluated phase signals (phase currents and / or phase voltages) of the electric machine. The latter method thus enables the saving of a speed sensor necessary for speed determination.

Dual-clutch transmissions require additional sensors compared to manual or automated step-change transmissions due to an additional input shaft. Aside from the additional hardware costs, the number of more used sensors also complicates data processing, including: also calculator error favors.

Overall, therefore, there remains the desire to reduce the number of sensors used, in particular to speed sensors in the drive train of a motor vehicle transmission, without having to accept sacrifices in safety and ride comfort while driving.

The object is achieved on the one hand by a method for a drive train of the type mentioned above, wherein the control means a momentary speed and / or a momentary direction of rotation of the gear shaft taking into account the instantaneous speed and / or the instantaneous direction of rotation of the electric machine and taking into account a gear ratio the translation level is calculated.

This method allows a simplified structure of the step change gear, since a sensor can be omitted on the transmission shaft. The instantaneous speed and / or the instantaneous direction of rotation of the transmission shaft is thus not determined by a sensor, but calculated using the control device. The speed and / or direction of rotation of the electric machine is determined by a sensor arranged on the rotor shaft and communicated to the control unit. Alternatively, the speed and / or direction of rotation of the electric machine can be determined by an evaluation of phase signals of the electric machine.

The ratio of the translation stage is stored in the memory of the control unit. The value of the translation stage can be d. Number of meshing gears be positive or negative.

The instantaneous speed of the gear shaft is then calculated as follows. $$\text{Speed d}\text{.Getriebewelle}=\frac{\text{Gear ratio d}\text{.Übersetzungsstufe}}{DreHzaHld\text{,}elektriscHenMascHine}$$

The current direction of rotation d. Gear shaft is taking into account the current direction of rotation d. electric machine or the rotor shaft and calculated taking into account a sign of the transmission ratio of the gear ratio stage by means of the control unit. By this method, a rotation sensor can be omitted on the transmission shaft.

An advantageous embodiment provides that the sensor is designed to determine a rotational speed, as well as a direction of rotation.

Furthermore, the above object is achieved by a method for a drive train of the type mentioned, wherein the control means a momentary speed and / or instantaneous direction of rotation of the electric machine, taking into account the instantaneous speed and / or instantaneous direction of rotation of the gear shaft and taking into account a gear ratio of Translation level calculated.

By this method, a simplified construction of the electrical machine is possible because a sensor on the electric machine or on the rotor shaft of the electric machine can be omitted. The instantaneous speed and / or the instantaneous direction of rotation of the electric machine is thus not determined by a sensor, but calculated by means of the control device. The speed of the input shaft is determined by a sensor commonly arranged on the transmission shaft and communicated to the control unit. The transmission ratio of the translation stage is stored in the memory of the control unit. The instantaneous speed of the electric machine is then calculated as follows. $$\text{Speed d}\text{, Electric}\text{, machine}=\frac{\text{Gear ratio d}\text{.Übersetzungsstufe}}{DreHzaHld\text{,}Getriebewelle}$$

The current direction of rotation d. electric machine is taking into account the current direction of rotation d. Gear shaft and calculated taking into account a sign of the transmission ratio of the gear ratio stage by means of the control unit. By this method, a rotation sensor can be omitted on the transmission shaft.

It is if the sensor is designed to be able to determine a rotational speed as well as a rotational direction, so that the above-mentioned methods can be used in combination.

It is advantageous if the control unit calculates a current rotational speed and / or a direction of rotation of the electric machine or of the transmission shaft if a sensor arranged correspondingly on the electric machine or the transmission shaft fails. By this method, a redundant function of a speed determination can be created, which significantly increases the reliability.

It is particularly advantageous if the transmission shaft is a crankshaft, a clutch input side, an input shaft or an output shaft. The crankshaft may further include a disconnect clutch dividing the crankshaft into two parts, a first part of the crankshaft being rotationally connected to the engine and a clutch input side of the disconnect clutch, and a second part of the crankshaft being rotatably connected to a clutch output side of the disconnect clutch and the clutch input side of the clutch device is. The sensor provided for the crankshaft can be assigned to both the first and the second part of the crankshaft. An advantageous embodiment provides to arrange the sensor to the part of the crankshaft to which the electric machine is connected. Otherwise, the separating clutch for carrying out the method according to the invention is closed, so that both parts of the crankshaft have the same speed.

It is advantageous if a gear change is performed from an actual gear stage to a target gear stage, wherein the control unit monitors the instantaneous rotational speed of the input shaft and the instantaneous rotational speed of the output shaft and detects an error as soon as the ratio of the instantaneous rotational speed of the input shaft and the current speed of the output shaft within a predetermined period of time does not coincide with a gear ratio of the target gear stage.

As a result of this measure, the control unit, without an additional rotational speed sensor, can detect a switching error in good time and initiate countermeasures without requiring a second rotational speed sensor for comparing two rotational speed values. In this case, the control unit accesses the previously calculated speed value and the value determined by a speed sensor.

It is particularly advantageous if the electric machine is designed to drive the motor vehicle purely electrically or in combination with another drive motor.

Furthermore, it is advantageous if the coupling device is designed as a friction clutch, a synchronous clutch or a dog clutch.

If in the present document of a translation stage is mentioned, this is to be understood as a direct coupling of the corresponding components, which results in a ratio of 1: 1. In particular, results in drive trains with a crankshaft coaxially aligned electrical machine whose rotor is connected directly to the rotor shaft or the clutch input side of the coupling device, there is less inaccuracy in the calculation of the desired speed value. Because of the design results in gear stages a game in the gear train, which increases depending on the number of meshing gears and is taken into account in an advantageous embodiment of the control unit in the calculation in the calculation of the speed value to be determined.

• 1 zeigt einen schematisch dargestellten Antriebsstrang 10 zur Durchführung der erfindungsgemäßen Verfahren.
• 2 zeigt ein Flussdiagramm zur Durchführung der erfindungsgemäßen Verfahren.

The inventions will be described below by way of example with reference to the accompanying drawings.

• 1 shows a schematically illustrated drive train 10 for carrying out the method according to the invention.
• 2 shows a flowchart for carrying out the method according to the invention.

So shows 1 a drive train 10 with a control device 15 , an internal combustion engine 21 , a coupling device 50a and 50b and a step change gearbox 11 wherein the step change gear in this specific case as a dual-clutch transmission with an input shaft 61 and another input shaft 62 is trained.

The coupling device 50a has a clutch input side 51 on that with the crankshaft 31 rotatably connected. In addition, the coupling device 50a a coupling output side 52 on that with the input shaft 61 rotatably connected.

Furthermore, the in 1 Drive train shown a crankshaft 31 on, which in a first part d. crankshaft 31a and in a second part of the crankshaft 31b is divided. The first part 31a the crankshaft 31 is with the internal combustion engine 21 and with a clutch input side 39a a separating clutch 39 while the second part 31b the separating clutch 31 with the clutch input side 51 the coupling device 50a and with the coupling device 50b is rotationally connected.

In addition, the step change gearbox 11 a plurality of gears 71 and 72 on that the two input shaft 61 and 62 assigned. Here are the straight gears of the input shaft 61 assigned, while the odd gear ratios of the other input shaft 62 assigned. The gears 71 and 72 each consist of a fixed-gear idler gear pair. By means of the clutches 81 and 82 can be engaged in a gear, so that a drive power from the input shaft via a gear, so a fixed gear idler gear pair, to the output shaft 91 is transferable.

The output shaft 91 is with a differential 92 Connected to the drive power to the drive wheels 100a and 100b of the motor vehicle distributed.

Furthermore, the drive train 10 an electric machine 22 on, which is designed to the motor vehicle purely electrically or in combination with the internal combustion engine 21 to drive and / or act as a generator.

In 1 are several sensors 41a . 41b . 41c . 41d and 41e shown communicating with the control unit. Depending on the embodiment / method but not all sensors 41a . 41b . 41c . 41d and 41e needed and can thus be saved at the respective points.

In a first embodiment, the electric machine 22 when using the method according to the invention with the second part 31b the crankshaft 31 by means of a coupling device 59 rotatably connected. The coupling device 59 is in the power flow direction between a rotor shaft 23 the electric machine and the crankshaft 31 arranged. Further, in the power flow direction between the electric machine 22 and the second part 31b the crankshaft 31 a translation level i1 arranged (dotted line i1 ), which may be formed either as a gear stage or as a traction mechanism. The translation level i1 has a gear ratio which serves to reduce a high number of revolutions of the electric machine. The translation level i1 can also contain several gear stages.

Furthermore, the drive train 10 a sensor 41a in the form of a speed sensor, which on the rotor shaft 23 the electric machine 22 is arranged. At the crankshaft 31 does not become a sensor 41d needed, which can be saved accordingly at this point.

For the calculation of a current speed of the crankshaft 31 takes into account the control unit 15 in a process step S1 that of the speed sensor 41a determined speed value of the rotor shaft 23 or the speed value of the electric machine 22 that in a procedural step S2 the control unit 15 is communicated. In addition, the control unit takes into account 15 in the memory of the control unit 15 stored value of the translation ratio of the translation stage i1 , The speed of the crankshaft 31 then calculates in a process step S3 as follows: $$\text{Speed d}\text{.<figure-callout id="31" label="Curvy" filenames="DE102018203531A1\_0012.png" state="{{state}}">Curvy</figure-callout> 31}=\frac{\text{Gear ratio d}\text{Translation stage i1}}{DreHzaHld\text{,}elektr\text{,}MascHine22bzw\text{,}ROtOrw\text{,}23}$$

Further, on the sensor 41a be waived when determining the speed of the rotor shaft 22 or the electric machine 22 in a process step S12 via an evaluation of phase signals of the electrical machine 22 he follows. Subsequently, the process step S3 for the calculation d. Speed of the crankshaft 31 be performed.

I want the control unit 15 from the calculated speed d. crankshaft 31 close to the speed of the engine, the disconnect clutch 39 at the time of determining the speed of the electric machine 22 be closed.

In a second embodiment, the electric machine 22 while performing the procedure with the second part 31b the crankshaft 31 by means of a coupling device 59 rotationally connected. The coupling device 59 is in the power flow direction between a rotor shaft 23 the electric machine and the second part 31b the crankshaft 31 arranged. Further, in the power flow direction between the electric machine 22 and the crankshaft 31 a translation level i1 arranged (dotted line i1 ), which may be formed either as a gear stage or as a traction mechanism. The translation level i1 has a gear ratio which serves to reduce a high number of revolutions of the electric machine. The translation level i1 can also contain several gear stages.

Furthermore, the drive train 10 a sensor 41d in the form of a speed sensor, which on the second part 31b the crankshaft 31 is arranged. At the rotor shaft 23 the electric machine 2 does not become a sensor 41a needed, which can be saved accordingly at this point.

For the calculation of a current speed of the electric machine 22 takes into account the control unit 15 in a process step S1 that of the speed sensor 41d determined speed value of the crankshaft 31 that in a procedural step S2 to the control unit 15 is communicated. In addition, the control unit takes into account 15 in the memory of the control unit 15 stored value of the translation ratio of the translation stage i1 , The speed of the electric machine 22 then calculates in a process step S3 as follows: $$\text{Speed d}\text{, Electric}\text{, <figure-callout id="22" label="Machine" filenames="DE102018203531A1\_0012.png" state="{{state}}">Machine</figure-callout> 22}=\frac{\text{Gear ratio d}\text{Translation stage i1}}{DreHzaHld\text{,}Kurbelwelle31}$$

In a third embodiment, the electric machine 22 during the implementation of the method according to the invention with the clutch input side 51 by means of a coupling device 59 rotationally connected. The coupling device 59 is in the power flow direction between a rotor shaft 23 the electric machine 22 and the clutch input side 51 arranged. Further, in the power flow direction between the electric machine 22 and the clutch input side 51 a translation level i2 arranged (dotted line i2 ), which may be formed either as a gear stage or as a traction mechanism. The translation level i2 has a gear ratio which serves to reduce a high number of revolutions of the electric machine. The translation level i2 can also contain several gear stages.

Furthermore, the drive train 10 a sensor 41d in the form of a speed sensor located on the crankshaft 31 is arranged, wherein the second part 31b the crankshaft 31 non-rotatable with the clutch input side 51 connected is. At the rotor shaft 23 the electric machine 22 however, no speed sensor 41a needed, which can be saved accordingly at this point.

For the calculation of a current speed of the electric machine 22 takes into account the control unit 15 in a process step S1 that of the speed sensor 41d determined speed value of the crankshaft 31 that in a procedural step S2 the control unit is communicated. In addition, the control unit takes into account 15 in the memory of the control unit 15 stored value of the translation ratio of the translation stage i2 , The speed of the electric machine is then calculated in a method step S3 as follows: $$\text{Speed d}\text{, Electric}\text{, <figure-callout id="22" label="Machine" filenames="DE102018203531A1\_0012.png" state="{{state}}">Machine</figure-callout> 22}=\frac{\text{Gear ratio d}\text{Translation stage i2}}{DreHzaHld\text{,}Kurbelwelle31}$$

In a fourth embodiment of the first method according to the invention, the electric machine 22 during the implementation of the method according to the invention with the clutch input side 51 by means of a coupling device 59 rotatably connected. The coupling device 59 is in the power flow direction between a rotor shaft 23 the electric machine 22 and the clutch input side 51 arranged. Further, in the power flow direction between the electric machine 22 and the clutch input side 51 a translation level i2 arranged (dotted line i2 ), which may be formed either as a gear stage or as a traction mechanism. The translation level i2 has a gear ratio which serves to reduce a high number of revolutions of the electric machine. The translation level i2 can also contain several gear stages.

Furthermore, the drive train 10 a sensor 41a in the form of a speed sensor, which on the rotor shaft 23 the electric machine 22 is arranged. At the clutch input side 51 or on the non-rotatably connected crankshaft 31 however, no speed sensor 41d needed, which can be saved accordingly at this point.

For calculating a current speed of the clutch input side 51 or the crankshaft 31 takes into account the control unit 15 in a process step S1 that of the speed sensor 41a determined speed value of the electric machine 22 or the rotor shaft 23 that in a procedural step S2 to the control unit 15 is communicated. In addition, the control unit takes into account 15 in the memory of the control unit 15 stored value of the translation ratio of the translation stage i2 , The speed of the crankshaft 31 or the clutch input side 51 then calculates in a process step S3 as follows: $$\text{Speed d}\text{.Kurbewelle}\text{, or}\text{, Kuppleingss}\text{, 51}=\frac{\text{Gear ratio d}\text{Translation stage i2}}{DreHzaHld\text{,}elektr\text{,}MascHine22bzw\text{,}ROtOrw\text{,}23}$$

In addition, on the speed sensor 41a be waived when determining the speed of the rotor shaft 22 or the electric machine 22 via an evaluation of phase signals of the electrical machine 22 he follows. Subsequently, in the process step S3 be transferred to the speed of the crankshaft 31 to calculate.

In a fifth embodiment, the electric machine 22 when carrying out the method with the input shaft 61 by means of a coupling device 59 rotatably connected. The coupling device 59 is in the power flow direction between a rotor shaft 23 the electric machine and the input shaft 61 arranged. Further, in the power flow direction between the electric machine 22 and the input shaft 61 a translation level i3 arranged (dotted line i3 ), which may be formed either as a gear stage or as a traction mechanism. The translation level i3 has a gear ratio which serves to reduce a high number of revolutions of the electric machine. The translation level i3 can also contain several gear stages.

Furthermore, the drive train 10 a sensor 41a for determining a rotational speed and for determining a direction of rotation, which on the rotor shaft 23 the electric machine 22 is arranged. At the input shaft 61 does not become a sensor 41b needed, which can be saved accordingly at this point.

For calculating a current speed of the input shaft 61 takes into account the control unit 15 in a process step S1 that of the speed sensor 41a determined speed value of the electric machine 22 or the rotor shaft 23 that in a procedural step S2 the control unit 15 is communicated. In addition, the control unit takes into account 15 in the memory of the control unit 15 stored value of the translation ratio of the translation stage i3 , The speed of the input shaft 61 then calculates in a process step S3 as follows: $$\text{Speed d}\text{, <figure-callout id="61" label="Input shaft" filenames="DE102018203531A1\_0012.png" state="{{state}}">Input shaft</figure-callout> 61}=\frac{\text{Gear ratio d}\text{Translation stage i3}}{DreHzaHld\text{,}elektr\text{,}MascHine22bzw\text{,}ROtOrw\text{,}23}$$

In this embodiment, the gear ratio i3 a negative value, which means that the rotor shaft 23 and the input shaft 61 rotate in opposite directions. Taking d. Direction of rotation d. electric machine 22 or d. rotor shaft 23 and considering the negative translation level i3 the result is a negative direction d as follows. input shaft 61 $$\text{Speed d}\text{, <figure-callout id="61" label="Input shaft" filenames="DE102018203531A1\_0012.png" state="{{state}}">Input shaft</figure-callout> 61}=\frac{\text{Gear ratio d}\text{Translation stage i3}}{DreHzaHld\text{,}elektr\text{,}MascHine22bzw\text{,}ROtOrw\text{,}23}$$

Further, on the sensor 41a be omitted if the determination of the speed or the direction of rotation of the rotor shaft 22 or the electric machine 22 in a process step S12 via an evaluation of phase signals of the electrical machine 22 he follows. Subsequently, then the process step S3 for the calculation d. Speed of the input shaft 61 be performed.

In a sixth embodiment, the electric machine 22 during the implementation of the method according to the invention with the input shaft 61 by means of a coupling device 59 rotatably connected. The coupling device 59 is in the power flow direction between a rotor shaft 23 the electric machine and the input shaft 61 arranged. Further, in the power flow direction between the electric machine 22 and the input shaft 61 a translation level i3 arranged (dotted line i3 ), which may be formed either as a gear stage or as a traction mechanism. The translation level i3 has a gear ratio, which serves to reduce a high number of revolutions of the electric machine. The translation level i3 can also contain several gear stages.

Furthermore, the drive train 10 a sensor 41b in the form of a speed sensor located on the input shaft 61 is arranged. At the rotor shaft 23 the electric machine 22 however, no speed sensor 41a needed, which can be saved accordingly at this point.

For calculating a current speed of the rotor shaft 23 or the speed of the electric machine takes into account the control unit 15 in a process step S1 that of the speed sensor 41b determined speed value of the input shaft 61 that in a procedural step S2 to the control unit 15 is communicated. In addition, the control unit takes into account 15 in the memory of the control unit 15 stored value of the translation ratio of the translation stage i3 , The speed of the electric machine is then calculated in a method step S3 as follows: $$\text{Speed d}\text{.<figure-callout id="22" label="elektr Machine" filenames="DE102018203531A1\_0012.png" state="{{state}}">elektr </figure-callout>}\text{Machine}\text{22}=\frac{\text{Gear ratio d}\text{Translation stage i3}}{DreHzaHld\text{,}einGanGswelle61}$$

In a seventh embodiment, the electric machine 22 during the implementation of the method according to the invention with the output shaft 91 by means of a coupling device 59 rotatably connected. The coupling device 59 is in the power flow direction between a rotor shaft 23 the electric machine and the output shaft 91 arranged. Further, in the power flow direction between the electric machine 22 and the output shaft 91 a translation level i4 arranged (dotted line i4 ), which may be formed either as a gear stage or as a traction mechanism. The translation level i4 has a gear ratio which serves to reduce a high number of revolutions of the electric machine. The translation level i4 can also contain several gear stages.

Furthermore, the drive train 10 in this embodiment, a sensor 41c in the form of a speed sensor, which on the output shaft 91 is arranged. At the rotor shaft 23 the electric machine 22 however, no speed sensor 41a needed, which can be saved accordingly at this point.

For calculating a current speed of the rotor shaft 23 or the speed of the electric machine takes into account the control unit 15 in a process step S1 that of the speed sensor 41c determined speed value of the output shaft 91 that in a procedural step S2 to the control unit 15 is communicated. In addition, the control unit takes into account 15 in the memory of the control unit 15 stored value of the translation ratio of the translation stage i4 , The speed of the electric machine is then calculated in a method step S3 as follows: $$\text{Speed d}\text{.<figure-callout id="22" label="elektr Machine" filenames="DE102018203531A1\_0012.png" state="{{state}}">elektr </figure-callout>}\text{Machine}\text{22}=\frac{\text{Gear ratio d}\text{Translation stage i4}}{DreHzaHld\text{,}Abtriebswelle91}$$

In an eighth embodiment, the electric machine is 22 while performing the procedure with the output shaft 91 by means of a coupling device 59 rotatably connected. The coupling device 59 is in the power flow direction between a rotor shaft 23 the electric machine and the output shaft 91 arranged. Further, in the power flow direction between the electric machine 22 and the output shaft 91 a translation level i4 arranged (dotted line i4 ), which may be formed either as a gear stage or as a traction mechanism. The translation level i4 has a gear ratio which serves to reduce a high number of revolutions of the electric machine. The translation level i4 can also contain several gear stages.

Furthermore, the drive train 10 a sensor 41a in the form of a speed sensor, which on the rotor shaft 23 the electric machine 22 is arranged. At the output shaft 91 however, no speed sensor 41c needed, which can be saved accordingly at this point.

For calculating a current speed of the output shaft 91 takes into account the control unit 15 now in one process step S1 that of the speed sensor 41a determined speed value rotor shaft 23 or the electrical machine 22 that in a procedural step S2 to the control unit 15 is communicated. In addition, the control unit takes into account 15 in the memory of the control unit 15 stored value of the translation ratio of the translation stage i4 , The speed of the output shaft 91 then calculates in a process step S3 as follows: $$\text{Speed d}\text{, <figure-callout id="91" label="Output shaft" filenames="DE102018203531A1\_0012.png" state="{{state}}">Output shaft</figure-callout> 91}=\frac{\text{Gear ratio d}\text{Translation stage i4}}{DreHzaHld\text{,}elektr\text{,}MascHine22bzw\text{,}ROtOrw\text{,}23}$$

Furthermore, on the speed sensor 41a be waived when determining the speed of the rotor shaft 22 or the electric machine 22 in a process step S12 via an evaluation of phase signals of the electrical machine 22 he follows. Subsequently, the above-explained method for calculating d. Speed of the output shaft 91 in a process step S3 be performed.

Is the control unit 15 the currently sensed and / or calculated speed value to the output shaft 91 and to the input shaft 61 After performing one of the preceding embodiments of the invention, is a monitoring of a switching operation of an actual gear in a target gear ratio by means of the control unit 15 possible. In this case, the control unit detects 15 in a process step S4 an error as soon as the ratio of the current speed of the output shaft 91 and the current speed of the input shaft 61 does not coincide with a gear ratio of the target gear within a predetermined period of time. Subsequently, a driver in a procedural step S5 a corresponding signal, such as a warning, issued.

In a ninth embodiment, the electric machine 22 when carrying out the method with the input shaft 61 by means of a coupling device 59 rotatably connected. The coupling device 59 is in the power flow direction between a rotor shaft 23 the electric machine 22 and the input shaft 61 arranged. Further, in the power flow direction between the electric machine 22 and the input shaft 61 a translation level i3 arranged (dotted line i3 ), which may be formed either as a gear stage or as a traction mechanism. The translation level i3 has a gear ratio which serves to reduce a high number of revolutions of the electric machine. The translation level i3 can also contain several gear stages.

Furthermore, the drive train 10 a sensor 41a in the form of a speed sensor, which on the rotor shaft 23 the electric machine 22 is arranged. At the input shaft 61 is also a speed sensor 41b arranged. In one process step S0 determines the control unit 15 a failure of the speed sensor 41b , so the control unit 15 no instantaneous speed value to the input shaft 61 is present. This causes the control unit the instantaneous speed of the input shaft 61 according to the method steps shown above S1 . S2 . S12 and S3 to calculate.

LIST OF REFERENCE NUMBERS

10

powertrain

11

Speed gearbox

15

control device

21

internal combustion engine

22

Electric machine

23

rotor shaft

31

crankshaft

31a

First part d. crankshaft

31b

Second part d. crankshaft

39

separating clutch

39a

Input side d. separating clutch

39b

Output side d. separating clutch

41a, 41b, 41c

sensors

41d, 41e

sensors

50a

coupling device

50b

Further coupling device

51

Clutch input side

52

Clutch output side

59

coupling device

61

input shaft

62

Further input shaft

71

Plurality of gears

72

Other gear wheels

81

clutches

82

Further clutches

91

output shaft

92

differential

100a

Drive wheel d. motor vehicle

100b

Drive wheel d. motor vehicle

i1, i2, i3, i4

translation stages

Claims (6)

Method for a drive train (10) of a motor vehicle having an electric machine (22) and a variable speed transmission (11), which has an input shaft (61), an output shaft (91) and a plurality of gear stages (71) which are actuated by means of clutches (81 ) and with a control device (15) for controlling the drive train (10), wherein the electric machine (22) via a translation stage (i1, i2, i3, i4) coupled to a transmission shaft or by means of a coupling device ( 59) can be coupled, wherein an instantaneous speed and / or a momentary direction of rotation of the electric machine is determined by an evaluation of phase signals of the electric machine (22) or via a sensor (41a, 41b, 41c, 41d), characterized by the method step, the control device (15) has an instantaneous rotational speed and / or an instantaneous rotational direction of the transmission shaft (31, 51, 61, 91), taking into account the instantaneous rotational speed and / or the torque ntanen direction of rotation of the electric machine (22) and taking into account a gear ratio of the translation stage (i1, i2, i3, i4) calculated. Method for a drive train (10) of a motor vehicle having an electric machine (22) and a variable-speed transmission (11), which has an input shaft (61), an output shaft (91) and a plurality of gear stages (71) which are actuated by respective clutches ( 81) and with a control device (15) for controlling the drive train (10), wherein the electric machine (22) via a transmission stage (i1, i2, i3, i4) with a transmission shaft (31,51, 61,91) or coupled by means of a coupling device (59), wherein the gear shaft (61) has a sensor (41b) to determine a momentary speed and / or a momentary direction of rotation of the gear shaft, characterized by the step that the Control device (15) a current speed and / or a momentary Direction of rotation of the electric machine (22) taking into account the instantaneous speed and / or the current direction of rotation of the transmission shaft (31,51,61,91) and taking into account a gear ratio of the gear ratio (i1, i2, i3, i4) calculated. Method for a drive train (10) of a motor vehicle according to Claim 1 or 2 , characterized in that the control unit (15) calculates an instantaneous rotational speed and / or instantaneous rotational direction of the electric machine (22) or an instantaneous rotational speed and / or instantaneous rotational direction of the transmission shaft (31, 51, 61, 91), if at the electrical machine (22) or the transmission shaft (31,51,61,91) arranged sensor fails. A drive train (10) of a motor vehicle for applying a method according to any one of the preceding claims, characterized in that the transmission shaft is a crankshaft (31), a clutch input side (51), an input shaft (61) or an output shaft (91). Method for a drive train (10) of a motor vehicle according to one of the preceding claims, characterized in that a gear change from an actual gear stage to a target gear stage is performed, wherein the control unit a current speed of the input shaft (61) and a current speed of Monitor output shaft (91) and detected an error when the ratio of the current speed of the output shaft (91) and the current speed of the input shaft (61) within a predetermined period of time does not coincide with a gear ratio of the target gear. Drive train (10) of a motor vehicle for applying a method according to one of the preceding claims, characterized in that the electric machine (22) is adapted to drive the motor vehicle purely electrically or in combination with another drive motor (21).

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