DE102009021960A1 - Method for controlling traction mechanism drive of drive unit of motor vehicle, involves determining reaction variable acting on units, and controlling relevant influencing variable of units depending on reaction variable - Google Patents

Abstract

The method involves coupling set of units (13, 15, 17) to each other by a traction mechanism (3). A reaction variable i.e. axle load, acting on one of the units is determined by a measuring device and a model of a traction mechanism drive (1), where the reaction variable depends on an operating state of the units. A relevant influencing variable of the units is controlled depending on the reaction variable, and the model exhibits a static component and a factor for dynamic super elevation. The axle load is monitored and/or limited by a controller. An independent claim is also included for a controller of a drive unit of a motor vehicle.

Description

The The invention relates to a method for controlling a traction mechanism drive with a variety coupled by means of a traction means aggregates of a motor vehicle.

Traction drives are known, they may have as traction means, for example, a belt or a chain and can transmit torques by means of tensile forces between units. The units may be, for example, hydraulic, electrical and / or pneumatic energy converters, in particular pumps, compressors and / or generators, as well as deflection and tensioning devices. To transmit the torques, it is known to subject the traction means with a bias voltage and to control these. From the DE 102 35 533 A1 is a traction mechanism for an internal combustion engine and method for tensioning a traction means known. In particular, a tensioning arm is controlled such that it assumes a dependent of an operating condition of an internal combustion engine position for tensioning a traction means. The DE 41 14 716 C2 discloses a method for controlling a belt tension of a belt drive, preferably for internal combustion engines of motor vehicles, wherein the belt tension is adjustable by a tension roller whose pressure force is adjustable via an actuator, wherein a state of charge of a battery and / or an on state of the belt driven units monitored and the belt tension is adjusted in response to the state of charge of the battery and / or the on state of the belt-driven units via an actuator.

task The invention is to enable an improved traction mechanism, in particular an inexpensive to produce, easier building and / or space-saving.

The Task is in a method for controlling a traction mechanism drive with a variety coupled by means of a traction means aggregates a motor vehicle solved. There are one determining one of an operating state of the plurality of units dependent and acting on a first aggregate of the plurality of aggregates Reaction size and controlling at least one relevant influencing variable of the large number of aggregates provided depending on the reaction size. Under influence each can influence the aggregates are of suitable size, For example, direct-acting control variables or indirectly acting other sizes.

Advantageous may be the first aggregate in terms of reaction size be controlled and / or monitored. At the reaction size it may, for example, a wear and / or design-relevant size of the first unit act. It is advantageously possible with respect to the aggregate the response size weaker, cheaper and / or easier to design and this by means of the control in dependence monitor the reaction size and / or to limit so that, despite the weaker interpretation no overload and / or unwanted reduction a lifetime of the first unit may occur. Under traction drive can be understood the traction means including all coupled aggregates become. Under aggregates can be a set of interacting individual Machinery, apparatus and / or parts are understood. present In particular, mechanical energy converters, the Driving traction drive or driven by this and other parts, such as a clamping device and / or Pulleys are understood. Under operating state, an actual operating state the plurality of aggregates, in particular in the sense of a vectorial and / or multi-size size understood become. However, it can also be a predicted under the operating condition or in the future expected value of the operating state be understood. In particular, it is conceivable to make a prediction the operating state with regard to a worst-case view or worst case Consideration for the reaction size to understand. Advantageously, the reaction size also depending on the expected value and / or the worst to be assumed.

at An embodiment of the method is determining the reaction quantity as one on an axis of the first unit acting axle force provided. The axle power will induced and has due to tensile forces of the traction device besides other sizes, such as one Speed, an effect on wear and / or a lifetime of the first unit and is therefore design-relevant. Advantageously, monitored by means of the control of the axle force and / or limited, so that advantageously the first unit is less interpretable without thereby the operation of the Traction drive impaired and / or a higher Wear of the first unit is given.

In a further embodiment of the method, a determination of the reaction variable by means of a model of the traction mechanism drive and the plurality of units are provided. Alternatively and / or additionally, it is provided that the model has a static component and a factor for a dynamic superelevation and / or that the model has a static component and a summand for the dynamic superelevation and / or that the model has a polynomial n-th Has order with n = 1, 2, 3 ... for the dynamic cant. Alterna tively and / or additionally, a determination of the reaction variable by means of a measuring device is provided. Advantageously, the reaction variable can be carried out either by means of the model while saving the measuring device, in addition to a measurement of the measuring device to improve a measuring quality or only by means of the measuring device while saving computing power of a corresponding control or a corresponding control device of the traction drive. Advantageously, in order to save computing power of the control device, the model can be simplified so that it has the static component and a comparatively easily determinable factor for the dynamic cant. The same advantageous procedure can alternatively and / or additionally be carried out by the addition of a summand for the dynamic elevation. For a particularly good model quality, it is conceivable to provide the polynomial of the nth order for the dynamic cant.

F_A1,dyn

die Achskraft,

F_A1,stat

die mittels geometrischen Gegebenheiten des Zugmitteltriebs, an den Aggregaten anliegenden und/oder prädizierten Drehmomenten und einer Vorspannkraft des Zugmittels ermittelbare statische Komponente der Achskraft und

d

der Faktor für die dynamische Überhöhung sind

vorgesehen. Vorteilhaft kann F_A1,stat auf einfache Art und Weise mittels den geometrischen Gegebenheiten des Zugmitteltriebs angegeben werden und mittels des Faktors d für die dynamische Überhöhung korrigiert werden.In a further embodiment of the method, the reaction variable is determined by means of the formula: F A1, dyn = F A1, stat · D, in which

F _{A1, dyn}

the axle force,

F _{A1, stat}

the by means of geometric conditions of the traction mechanism, applied to the aggregates and / or predicted torques and a biasing force of the traction means ascertainable static component of the axle force and

d

are the factor for dynamic elevation

intended. Advantageously, F _{A1, stat} can be specified in a simple manner by means of the geometrical conditions of the traction mechanism drive and corrected by means of the factor d for the dynamic superelevation.

M_An

ein mittels des Zugmittels auf ein n-tes Aggregat übertragenes n-tes Drehmoment,

r_An

zumindest ein n-ter Radius einer dem Zugmittel und dem n-ten Aggregat zugeordneten n-ten Riemenscheibe,

β_U,A1

ein Umschlingungswinkel des Zugmittels um eine dem ersten Aggregat zugeordnete erste Riemenscheibe sind

vorgesehen. Unter Umschlingungswinkel kann ein Winkel verstanden werden, der einem Bogen der Riemenscheibe entspricht, an dem das Zugmittel anliegt.In a further embodiment of the method, determining the static component F _{A1, stat of} the reaction variable by means of a relationship for a static equilibrium with the formula: F A1, stat = Function (m At , r At , β U, A1 , F V ) With
n = 0 1, 2, 3, ...,
where F _{V is} a biasing force of the traction means,

M _on

an n-th torque transmitted to an n-th aggregate by means of the traction means,

r _on

at least one n-th radius of the n-th pulley associated with the traction means and the n-th aggregate,

β _{U, A1}

a wrapping angle of the traction means are about a first pulley associated with the first pulley

intended. By wrap angle, an angle can be understood that corresponds to an arc of the pulley on which the traction means is applied.

Advantageously, F _{A1, stat} by means of constants, the biasing force, the wrap, the at least one radius and applied to the aggregates of the traction mechanism torque can be determined in a simple manner. Optionally, the moments can be referred back to a reference radius of the n radii of a reference pulley, so that the moments of the remaining units can go into the function without further correction.

In a further embodiment of the method, determining the factor d for the dynamic overshoot as a function of a rotational speed n (t) and an engine torque M _mot (t) of the drive unit and / or determining the factor d for the dynamic superelevation as a function of the operating state the plurality of units, in particular at least one of the units provided. Advantageously, the operating state can also be included in the dynamic cant. The operating state of the units also has an influence on the reaction variable, for example in the form of an attenuation of Drehunförmigkeiten that are transmitted by means of the traction device between the units.

In a further embodiment of the method, a determination of the factor d for the dynamic cant is provided by means of a characteristic map. Advantageously, computing power of the corresponding control unit can thereby be saved. Alternatively and / or additionally, the map can be determined in advance, for example by means of tests on a test bench and / or a mathematical simulation of the traction drive. Advantageously results in a particularly accurate map. An engine map can be understood to be an nm-dimensional characteristic map, which associates at least one input variable with at least one output variable, in particular also a one-dimensional characteristic map in the sense of a characteristic curve. Alternatively and / or additionally, the map can be carried out as a two-dimensional map over the rotational speed n (t) and the engine torque M _mot (t). Advantageously, the speed and the engine torque can be taken into account. Alternatively and / or additionally can also a third dimension in the form of a load state of at least one of the aggregates can be added to the map. The load condition can also have an effect on the damping or a measure of it. Alternatively and / or additionally, it is conceivable to design the characteristic field as an n-dimensional characteristic field, for example to record a further dimension with an operating state and / or the load state for each of the aggregates. Alternatively and / or additionally, for example, to increase a quality of measurement and / or to save computing power of the control unit, it is possible to determine the factor d for the dynamic elevation by means of the measuring device. The engine torque M _mot (t) can advantageously be present in the control unit or a corresponding control of an internal combustion engine of the motor vehicle, this being able to be determined, for example, by means of a corresponding gas pressure characteristic map and / or a model of internal engine combustion. It is conceivable to determine the corresponding characteristic map by means of preliminary calculations, tests and / or simulation methods in advance.

In a further embodiment of the method, setting a dynamic threshold value F _{A1, dyn, max} for the response variable and / or triggering the at least one relevant influencing variable of the aggregates is provided such that the dynamic threshold value F _{A1, dyn, max is} not exceeded as far as possible. The dynamic threshold value F _{A1, dyn, max} may advantageously be a maximum possible axial force of the first unit, which should not be exceeded as far as possible or at least only for a short time and to the smallest possible extent. Advantageously, a negative feedback, in the ideal case as a control loop, take place. In a simple form, a comparison between the reaction variable as an actual variable with the dynamic threshold F _{A1, dyn, max} done, depending on the result of the comparison, a switching operation can be triggered, for example, one of the units to reduce a torque applied thereto are controlled can, for example by means of separation. It is conceivable to define a plurality of such dynamic threshold values F _{A1, dyn, max} , wherein further measures, for example disconnection of a second aggregate, may occur, for example, if the reaction variable again falls below the dynamic threshold value F _{A1, dyn, max} . In order to avoid or at least reduce vibrations, a hysteresis or a further switching point lying below the dynamic threshold value F _{A1, dyn, max can be} provided for a switch-back.

In a further embodiment of the method, setting the dynamic threshold value F _{A1, dyn, max} for the reaction variable and / or recalculating the dynamic threshold value F _{A1, dyn, max} to a static threshold F _{A1, stat, max} dependent on the operating state is determined by the formula F _{A1, stat, max} = F _{A1, dyn, max} / d, where d depends on the operating state, in particular on the rotational speed n (t) and the engine torque M _mot (t) and / or the load state of the at least one unit and / or controlling the second torque M _{A2 of} the second unit such that the static component F _{A1, stat of} the reaction variable does not exceed the static threshold value F _{A1, stat, max} and / or controlling the third torque M _{A3 of} the third unit so that the static component F _{A1, stat of} the reaction variable the static threshold F _{A1, stat, max} as possible not exceeding provided. Generalized is, alternatively and / or additionally, controlling at least one n-th torque M _{n3 of} the nth aggregate such that the static component F _{A1, stat of} the reaction variable ( 31 ) does not exceed the static threshold value F _{A1, stat, max} , with n = 1, 2, 3,. Advantageously, the control can take place in the static component of the reaction variable which is comparatively easy to determine and calculate. Alternatively and / or additionally, it is conceivable to evaluate only maximum values, for example resulting from torsional vibrations and / or rotational irregularities, which are transmitted between the units by means of the traction means in order to reliably enable a limitation of the reaction variable or of the dynamic component.

at Another embodiment of the method is a Determining a remaining life of the aggregate by means of Evaluate the reaction size over one Total operating time of the traction means and forming accumulated loads provided. The total lifetime can advantageously be accumulated by means of an accumulated Loading, for example by integrating the reaction size over the Total operating time are estimated.

at In another embodiment, the above-described Method for two or more aggregates of the plurality of Aggregates performed. There are for each the aggregates the advantages described above. It can be beneficial the entire traction drive controlled and / or monitored be in terms of a variety of reaction sizes the respective aggregates.

The Task is also in a traction drive of a drive unit of a motor vehicle, designed, furnished and / or designed solved for carrying out a method described above. This results in the advantages described above.

The object is also in a control unit of a drive unit of a motor vehicle, constructed, set up and / or designed for carrying out a method described above solved. This results in the advantages described above. Under control device can be understood an electronic and / or digital control of the drive unit, such as an engine control unit, and / or a closed unit of a higher-level central control or control device of the motor vehicle. However, the control unit may alternatively and / or additionally also have mechanical, pneumatic and / or hydraulic components.

Further Advantages, features and details of the invention will become apparent the following description, in which - optionally with reference to the drawings - various embodiments are described in detail. Same, functionally identical and / or similar Parts are provided with the same reference numerals.

It demonstrate:

1 a schematic view of a traction mechanism drive with a plurality coupled by means of a traction means units; and

2 a schematic view of a control of at least one relevant influence

1 shows a schematic view of a traction mechanism drive 1 with a plurality by means of a traction device 3 coupled aggregates of a motor vehicle only partially shown 5 , A circulation direction of the traction device 3 is in 1 by means of an arrow 7 symbolizes. The traction drive 1 has a drive unit 9 on, by means of a reference pulley 11 the traction means 3 assigned to transmit a torque. The traction drive 1 also has a first unit 13 , a second aggregate 15 and a third unit 17 on, each with a first pulley 19 , a second pulley 21 and a third pulley 23 the traction means 3 assigned to transmit a torque. To induce a bias is the traction means 3 of Zugmittelbetriebs 1 a tension roller 25 a tensioning device, not shown, of the traction mechanism drive 1 assigned. For increasing a wrap angle β _{U, A1 of} the first pulley 19 of the first aggregate 13 is between the first pulley 19 and the second pulley 21 a substantially torque-free pulley 27 connected. At the first unit 13 it may be, for example, a hydraulic pump for providing hydraulic energy. At the second unit 15 For example, it can be an electrical energy converter, for example a generator and / or a starter generator of a corresponding internal combustion engine of the motor vehicle 5 act. At the third unit 17 For example, it may be a compressor, for example an air conditioning compressor of the motor vehicle 5 act. The drive unit may be the internal combustion engine of the motor vehicle 5 , An electric motor for driving the motor vehicle 5 and / or a combination of both in terms of a hybrid drive.

2 shows a schematic view of a control of at least one relevant influence variable 29 the in 1 shown aggregates depending on a on the first unit 13 acting reaction size 31 , For controlling the influencing variable 29 is a regulator 33 intended. The influence 29 has a drive influence variable 35 for controlling the drive unit 9 , a first influence part size 37 for controlling the first unit 13 and a second influence part size 39 for controlling the second unit 15 on. If necessary, the controller 33 also the third unit 17 drive yourself, which is not closer in 2 is shown. According to the controller of the controller 33 turns a first output 41 of the drive unit 9 , a second output 43 of the first aggregate 13 and a third output 45 of the second aggregate 15 one. With the output variables 41 to 45 These are sizes of which the reaction size 31 directly or indirectly depends. The output variables 41 to 45 can be measurable or determinable and become a model 47 fed. By means of the model 47 becomes the reaction size 31 determined. The reaction size 31 can with a leader 49 , for example in the form of a threshold, and the controller 33 be supplied.

Alternatively and / or additionally, it is possible the reaction size 31 by means of an in 2 Dashed measuring device shown 51 to determine directly.

This in 2 shown control or control scheme may alternatively and / or additionally for the second unit 15 and the third aggregate 17 , in particular for the pulley 27 and / or the tension roller 25 be performed. At the reaction size 31 each of these may be an axle force acting on the corresponding unit. Advantageously, the reaction size 31 , in particular the axle force, as an actual value and / or expected value, in particular as maximum expected value on the basis of the output variables 41 to 45 on the aggregates, for example 13 to 17 applied torques, a drive torque of the drive unit 9 and / or a rotational speed of the drive unit 9 predicted and / or predicted. By means of the model 47 that the geometric conditions of the traction mechanism drive 3 From this, it can become a static component of the reaction variable 31 determined by means of a correction value for a dynamic Überhö hung, for example, a factor can be corrected. Advantageously, the model 47 So be designed simplified, for example by means of maps that can be determined in advance by means of simulation methods and / or measurements are performed. Advantageously, the controller 33 based on the calculated reaction size 31 For example, the axle forces the aggregates 13 to 17 as well as the drive unit 9 so control that a discharge thus reducing the reaction size 31 he follows. Advantageously, thereby a protection of not actually controllable aggregates of the motor vehicle 5 take place, for example, such aggregates that are safety-relevant and therefore must not be turned off. Advantageously, it is also possible, the reaction size 31 over a total operating time of the traction mechanism drive 1 to detect and calculate therefrom an accumulated load of the corresponding unit, wherein advantageously a remaining life, in particular on the basis of axial forces or accumulated axial forces, is possible.

By way of example, a critical value for the axial force of the first unit may be between 500 Newton and 10000 Newton, in particular between 2000 Newton and 8000 Newton, preferably between 3000 Newton and 5000 Newton. It is possible to set a threshold for this, by means of the controller 33 is monitorable, with regulatory intervention of the regulator 33 be done so that when approaching or at the latest when exceeding the threshold value, a control intervention takes place, which lowers the response size below the threshold again. Advantageously, the reaction force 31 by means of the model 47 Simplified, the model 47 a static model and a dynamic increase of the engine torque M _mot (t) and the rotational speed n (t) of the internal combustion engine of the motor vehicle 5 depends. Advantageously, a threshold for the engine speed and the engine torque can be specified, the corresponding control intervention of the controller 33 trigger.

The calculation of a static component of the reaction variable 31 F _{A1, stat} can be advantageous on an idealized, static and frictionless model of traction drive 1 respectively.

It is conceivable, the reaction size 31 by the formula: F A1, dyn = F A1, stat · D, to investigate

It is also conceivable, the static component F _{A1, stat of} the reaction variable 31 as a function of the means of traction 3 torques transmitted to the units, at least one radius of one of the pulleys 11 . 19 . 27 . 21 . 23 , the wrap angle βU, A1 of the first pulley 19 and a biasing force of the traction means 3 to investigate

It is also conceivable prevailing conditions in the traction drive 1 to idealize, with an increase in the static axle force only in dependence on the engine speed and the at the traction drive 1 transmitted engine torque is defined, advantageously applied to the ancillaries torque not enter into the dynamic cant. Alternatively and / or additionally, however, it is also conceivable operating states of the other units 15 . 17 to be included in the dynamic elevation, for example in the form of an n-dimensional map, wherein for each operating state and / or load state of the aggregates 15 . 17 another dimension can be included in the map.

In the event that the factor for the dynamic cant does not depend on the other aggregates 15 . 17 Depending on dependent torques, can be advantageously a simple algebraic determination of a static threshold of the reaction variable 31 in the shape F A1, stat, max = F A1, dyn, max / d determine. Advantageously, a control of the controller 33 then in the size of the static component of the reaction size 31 respectively.

Alternatively and / or additionally, however, it is also conceivable to control the regulator 33 in the reaction size 31 perform with the static and the dynamic component, for example, a dynamic threshold F _{A1, dyn, max} as a reference variable 49 can be specified.

1

traction drive

3

traction means

5

motor vehicle

7

arrow

9

power unit

11

Reference pulley

13

first aggregate

15

second aggregate

17

third aggregate

19

first pulley

21

second pulley

23

third pulley

25

idler

27

idler pulley

29

effect size

31

response size

33

regulator

35

Drive influencing factor

37

first Influence portion size

39

second Influence portion size

41

first output

43

second output

45

third output

47

model

49

command variable

51

measuring device

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 10235533 A1 [0002]
• - DE 4114716 C2 [0002]

Claims (13)

Method for controlling a traction mechanism drive ( 1 ) with a plurality by means of a traction device ( 3 ) coupled units of a motor vehicle ( 5 ), comprising: - determining a condition dependent on an operating state of the plurality of aggregates and on a first aggregate ( 13 ) of the plurality of aggregates ( 9 . 13 . 15 . 17 ) acting reaction quantity ( 31 ), - controlling at least one relevant factor ( 29 ) of the plurality of aggregates ( 9 . 13 . 15 . 17 ) depending on the reaction size ( 31 ). Method according to the preceding claim, comprising: - determining the reaction quantity ( 31 ) as one on an axis of the first aggregate ( 13 ) acting axle force. Method according to one of the preceding claims, comprising at least one element of the following group: - determining the reaction quantity ( 31 ) by means of a model ( 47 ) of the traction mechanism drive ( 1 ) and the plurality of aggregates, - where the model ( 47 ) has a static component and a factor for dynamic elevation, - the model ( 47 ) has a static component and a summand for the dynamic elevation, - wherein the model ( 47 ) has an nth-order polynomial with n = 1, 2, 3 ... for the dynamic elevation - determining the reaction quantity ( 31 ) by means of a measuring device. Method according to the preceding claim, comprising: - determining the reaction quantity ( 31 ) by means of the formula F A1, dyn = F A1, stat · D, where F _{A1, dyn} the axle force, F _{A1, stat} which by means of geometrical conditions of the traction mechanism drive ( 1 ), on the aggregates ( 9 . 13 . 15 . 17 ) applied and / or predicted torques and a biasing force of the traction means ( 3 ) are determinable static component of the axle force and d are the factor for the dynamic cant. Method according to the preceding claim, with - determination of the static component F _{A1, stat of} the reaction variable ( 31 ) by means of a relationship for a static equilibrium with the formula: F A1, stat = Function (m At , r At , β U, A1 , F V ) with n = 0 1, 2, 3,..., where F _{V is} a pretensioning force of the traction means ( 3 ) M _to an means of traction means ( 3 ) to an n-th aggregate ( 13 n-tes transmitted torque, r _At at least one n-th radius of the traction means ( 3 ) and the n-th aggregate associated n-th pulley, β _{U, A1} a wrap angle of the traction means ( 3 ) around a first unit ( 13 ) associated first pulley ( 19 ) are. Method according to the preceding claim, comprising: determining the factor d for the dynamic cant as a function of a rotational speed n (t) and an engine torque M _mot (t) of the drive unit ( 9 ), - determining the factor d for the dynamic cant as a function of the operating state of the plurality of aggregates, in particular at least one of the aggregates ( 9 . 13 . 15 . 17 ). Method according to one of the preceding two claims, with at least one element of the following group: determination of the factor d for the dynamic superelevation by means of a characteristic map, determination of the characteristic field by means of a simulation of the traction drive ( 1 Determining the characteristic map as a two-dimensional characteristic map over the rotational speed n (t) and the engine torque M _{mot (t)} , determining the characteristic map as a three-dimensional characteristic map over the rotational speed n (t) and the engine torque M _{mot (t)} and a load state at least one of the aggregates ( 9 . 13 . 15 . 17 ). Determining the map as n-dimensional map with n = 1, 2, 3 ..., Determining the factor d for the dynamic elevation by means of the measuring device 51 ). Method according to one of the preceding claims, comprising: determining a dynamic threshold value F _{A1, dyn, max} for the reaction variable ( 31 ), - controlling the at least one relevant influencing variable ( 29 ) of the aggregates ( 9 . 13 . 15 . 17 ) so that the dynamic threshold F _{A1, dyn, max is} not exceeded as far as possible. Method according to the preceding claim, with at least one element of the following group: - definition of a dynamic threshold value F _{A1, dyn, max} for the reaction variable ( 31 ), - recalculating the dynamic threshold F _{A1, dyn, max} to a dependent on the operating condition static threshold F _{A1, stat, max} by means of the formula F A1, stat, max = F A1, dyn, max / D, where d depends on the operating state, in particular on the rotational speed n (t) and the engine torque M _mot (t) and the load state of the at least one engine, - controlling the second torque M _{A2 of} the second engine ( 15 ) such that the static component F _{A1, stat of} the reaction variable ( 31 ) does not exceed the static threshold value F _{A1, stat, max} , - controlling the third torque M _{A3 of} the third unit ( 17 ) such that the static component F _{A1, stat of} the reaction variable ( 31 ) does not exceed the static threshold value F _{A1, stat, max} , - controlling at least one n-th torque M _{An of} the n-th aggregate such that the static component F _{A1, stat of} the reaction variable ( 31 ) does not exceed the static threshold value F _{A1, stat, max} , with n = 1, 2, 3, ... Method according to one of the preceding claims, comprising: determining a remaining life of the first aggregate ( 13 ) by evaluating the reaction quantity ( 31 ) over a total operating time of the traction drive ( 1 ) and accumulated loads. Method according to one of the preceding claims, comprising: - performing the method for two or more aggregates of the plurality of aggregates ( 9 . 13 . 15 . 17 ). Traction drive of a drive unit ( 9 ) of a motor vehicle ( 5 ), constructed, arranged and / or adapted to carry out a method according to any one of the preceding claims. Control unit of a drive unit ( 9 ) of a motor vehicle ( 5 ), constructed, arranged and / or adapted to carry out a method according to any one of the preceding claims.