CN113383152B

CN113383152B - Method for operating an exhaust gas turbocharger

Info

Publication number: CN113383152B
Application number: CN202080013912.6A
Authority: CN
Inventors: S·海因肯; S·凯驰; F·弗雷斯; J·巴托洛姆
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2019-02-12
Filing date: 2020-02-04
Publication date: 2023-06-27
Anticipated expiration: 2040-02-04
Also published as: WO2020164948A1; DE102019201788A1; EP3924608A1; CN113383152A

Abstract

A method for operating an exhaust gas turbocharger (ATL) of an internal combustion engine is described, wherein the ATL is operatively connected to an electric machine and the rotational speed of the ATL can be adjusted via the electric machine. The method comprises determining a static or dynamic operating state of the internal combustion engine and reducing the actual rotational speed of the ATL via an electric machine in order to comply with an upper rotational speed limit of the ATL, wherein the electric machine is operated in dependence on the operating state of the internal combustion engine.

Description

Method for operating an exhaust gas turbocharger

Technical Field

The invention relates to a method for operating an exhaust gas turbocharger, in particular for monitoring the rotational speed thereof. The invention further relates to a control device, an internal combustion engine and a motor vehicle.

Background

In general, in particular in the field of motor vehicles, supercharging systems for internal combustion engines are known for supplying cylinders of the internal combustion engine with air having an overpressure for the combustion of fuel.

In order to provide air with an overpressure, for example, turbochargers and compressors are known. The turbocharger has a compressor and the turbocharger may be equipped with its own drive for the compressor, for example an electric motor, or the turbocharger is operated, for example with exhaust gases of an internal combustion engine, wherein the exhaust gases drive a turbine which is operatively connected/coupled to the compressor via a shaft. The latter is also called an exhaust gas turbocharger (ATL).

Furthermore, it is known, for example, from DE 10201001106780 A1, that the ATL can additionally have an electric drive in order to increase and decrease the rotational speed of the ATL. In particular, the rotational speed can thereby be reduced, when a smaller boost pressure is required or an excess of boost pressure should be prevented. DE 10200600237 A1 likewise describes a turbocharger with a motor, wherein the motor is controlled on the basis of the delay characteristic of the actual discharge energy applied to the turbine of the turbocharger in order to prevent overshoot (or overshoot) of the boost pressure, i.e. uebergschwingen. DE 10200504887 A1 discloses that the rotational speed of the turbocharger is kept within a defined rotational speed range via an electric machine coupled to the motor.

In the design of a turbocharger, particular attention must be paid to the maximum rotational speed that the turbocharger cannot exceed. In the event of an overrun, there is a risk of failure of the turbocharger until complete failure.

Due to component tolerances and aging effects, a rotationally precise adjustment (regulation) of the turbocharger with respect to all circumstances/operating points cannot be demonstrated. Sensor devices, such as turbocharger rotational speed sensors, are used for economical reasons in the field of motor cycle sports or sports cars.

Robustness against turbocharger impairment can be achieved by the virtual speed band of the turbocharger, which serves as a reserve for the effects described above. That is to say that the turbocharger is not operated at its maximum possible upper rotational speed limit. The turbocharger therefore nominally loses performance, since the boost pressure increase is correspondingly limited by the speed limit of the virtual speed band.

Thus, for example, in dynamic operation, a regulating element of the turbocharger, for example a Variable Turbine Geometry (VTG) regulating element for a turbine of the turbocharger and/or a Wastegate valve (or Wastegate valve), is briefly opened in order to compensate for the inertia-induced over-rotational speed. Such a method places extremely high demands on accuracy in terms of functionality and applicability, so that high outlay is incurred here.

Disclosure of Invention

The object of the present invention is to provide a method which at least partly overcomes the above-mentioned disadvantages.

This object is achieved by a method according to the invention, by a control device according to the invention, by an internal combustion engine according to the invention and by a motor vehicle according to the invention. Further advantageous embodiments of the invention are evident from the dependent claims and the following description of preferred embodiments of the invention.

According to a first aspect, the invention provides a method for operating an exhaust gas turbocharger (ATL) of an internal combustion engine, wherein the ATL is operatively connected to an electric machine and the rotational speed of the ATL is adjustable via the electric machine. The method comprises the following steps:

-determining a static or dynamic operating state of the internal combustion engine; and

-reducing the ATL actual rotational speed via an electric machine in order to comply with an upper rotational speed limit of the ATL, wherein the electric machine is operated in dependence of the operating state of the internal combustion engine.

The concept of monitoring, adjusting, manipulating, controlling, regulating is in connection with the present invention not only to include control in the true sense (without feedback) but also to include regulation (with one or more regulating loops).

The ATL is operatively connected to the electric machine as long as the electric machine can influence the rotational speed of the ATL, as is the case, for example, in an electrically assisted exhaust gas turbocharger. The electric machine is thus in particular directly coupled with the ATL and can be operated as a motor or as a generator. The electric machine can increase or decrease the ATL speed by the torque generated by the electric machine during motor operation, and can decrease the ATL speed during generator operation, for example, as a regenerative brake.

The internal combustion engine can be operated in at least two operating states, on the one hand in a static state (in particular a full-load operating state) and in a dynamic operating state, in order to achieve driver expectations, in particular acceleration expectations. The determination/detection of the operating state of an internal combustion engine is generally carried out by means of different operating parameters of the internal combustion engine and by means of operating parameters of components associated therewith, for example an exhaust gas turbocharger.

The upper limit of the ATL rotational speed corresponds to the maximum permissible ATL rotational speed that the ATL cannot exceed over a long period of time based on the component properties, in order to avoid creep (flieβen) of components of the ATL, in particular of its running wheels, for example.

In order to comply with this upper limit of the ATL rotational speed, the ATL actual rotational speed is reduced by means of the electric machine, in particular by its motor operation. The determined operating state of the internal combustion engine is decisive for the intervention in the motor into the ATL rotational speed. Because the motor is operated or adjusted accordingly, depending on whether static or dynamic operating conditions exist. In other words, depending on the operating state, a further control (actuation) acts on the motor. Furthermore, the motor is only intervened for reducing the ATL rotational speed.

The rotational speed overshoot of the ATL can thus be prevented in such a way that the motor accordingly acts on the rotational speed of the ATL. This rotational speed overshoot is caused, for example, by the mass inertia of the ATL running wheel.

By means of the method described above, it is possible to operate the ATL near its upper rotational speed limit without the above-described cut-off in the form of a virtual rotational speed band being provided as a rotational speed reserve for component protection. Thus, the full rotational speed band of the ATL can be fully utilized, thereby achieving a (nearly) full utilization of the nominal performance of the ATL.

In a further method variant, the electric machine can be controlled via the first control device when a static operating state is present and via the second control device when a dynamic operating state is present. Here, the use of "adjustment" may also mean control (manipulation). The electric machine can thus be operated or adjusted accordingly to the respective operating state of the internal combustion engine. Thus, the motor may be adjusted relatively more differentially.

Furthermore, the first adjusting device may have a first adjusting part and a second adjusting part for reducing the actual rotational speed of the ATL. The first and second regulating members may intervene/act depending on hysteresis characteristics of the actual boost speed and the actual ATL speed. As a result, the motor can be operated additionally relatively differently for the static operating state.

Furthermore, the upper rotational speed limit of the ATL may be a control parameter (fuhrungsgrograde βe) of the first and second regulating members.

In a further method variant, the electric machine can be operated in the dynamic operating state of the internal combustion engine as a function of the mass inertia of the ATL and/or the inertia of the boost pressure structure. The inertia of the boost pressure structure is generated, for example, by a delay in the gas path of the internal combustion engine, i.e. for example, due to the distance between the compressor (of the ATL) and the cylinder inlet. Thus, the intervention of the motor can be adjusted relatively more precisely in order to compensate for the rotational speed overshoot. In particular, the motor may be adjusted in view of the intervention time point, the intervention time period and/or the intervention intensity (i.e. the ATL rotational speed is reduced by the motor).

In a variant of the method, the mass inertia of the ATL and the inertia of the boost pressure structure can be taken into account by means of the characteristic curve. These characteristic curves (or characteristic lines) can be determined, for example, empirically at the test stand or by means of a mathematical model.

Furthermore, a dynamic operating state of the internal combustion engine may be present or determined when the boost pressure adjustment deviation is greater than a predetermined minimum pressure difference and the predicted boost pressure adjustment deviation is greater than a predetermined limit pressure. The boost pressure control deviation corresponds to the difference between the setpoint boost pressure and the actual boost pressure, wherein the setpoint boost pressure is used to achieve the driver's desired value (i.e., to achieve the setpoint motor torque) and can therefore likewise be derived from the driver's desired value. The actual boost pressure is generally detected via a pressure detection device correspondingly arranged in the air line of the internal combustion engine. In order to determine the dynamic operating state of the internal combustion engine, the boost pressure regulation deviation must exceed a predetermined minimum pressure difference. This is necessary in order to distinguish it from relatively small boost pressure regulation deviations, which may also occur during the regulation of the boost pressure in the stationary operating state of the internal combustion engine. Another condition for the presence of a dynamic operating state may be that the predicted boost pressure regulating deviation exceeds a predetermined limit pressure, wherein the exceeding of the limit pressure is an overshoot of the boost pressure (exceeding the nominal boost pressure). When both conditions are satisfied, there is a dynamic operating state of the internal combustion engine.

Furthermore, a static operating state of the internal combustion engine may be present or determined when the boost pressure adjustment deviation is smaller than a predetermined minimum pressure difference and/or the predicted boost pressure adjustment deviation is smaller than a predetermined limit pressure.

In a method variant, the predicted boost pressure regulation deviation may be determined as a function of the boost pressure gradient. The boost pressure gradient is here a temporal change of the actual boost pressure. From the boost pressure gradient, the kinematics of the ATL sheave can be deduced, especially taking into account the mass inertia.

Further, the ATL actual rotational speed may be detected via the motor. The availability of the motor and the sensor device connected thereto (in particular the rotational speed detection device) makes it possible to precisely detect the rotational speed of the shaft of the ATL and its changes. Thus, the motor can be adjusted relatively more precisely for the rotational speed adjustment of the ATL.

In one alternative, the ATL may have an adjusting assembly, in particular a variable turbine geometry and/or a wastegate valve. In this case, it is achieved that the ATL actual rotational speed is reduced by the electric motor when the actuating assembly is adjusted in the open limit position. In this case, the open limit position is indicated by the adjusting assembly being adjusted in such a way that in the case of a variable turbine geometry the flow cross section for the exhaust gas is maximum and in the case of a wastegate valve the valve thereof is opened to the greatest extent in order to guide as much exhaust gas as possible around the turbine.

According to a second aspect, the present disclosure provides a control device for an ATL of an internal combustion engine, wherein the control device is arranged to implement the method according to the present invention.

According to a third aspect, the present disclosure provides an internal combustion engine with an ATL and a control device according to the second aspect.

According to a fourth aspect, the present disclosure provides a motor vehicle with an internal combustion engine according to the third aspect.

Drawings

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings. Wherein:

FIG. 1 schematically illustrates one embodiment of a motor vehicle with an internal combustion engine;

fig. 2a,2b show the input parameters and output parameters of the static and dynamic rotational speed regulation of the exhaust gas turbocharger;

fig. 3a-c schematically show a static rotational speed regulation, a rotational speed regulation by means of an electric motor and a thermodynamic regulation;

fig. 4 schematically shows a dynamic rotational speed regulation; and is also provided with

Fig. 5a,5b show schematic curves for the boost pressure, the rotational speed for the exhaust gas turbocharger and the adjusting element for the exhaust gas turbocharger.

Detailed Description

Fig. 1 shows a motor vehicle 1 with a supercharging system 9 in the form of a motor 3 (internal combustion engine) and an exhaust gas turbocharger (ATL) which is controlled by a control device 21. The control device 21 is configured as a motor controller.

The invention is not limited to one determined motor type. It may be an internal combustion engine, which may be configured, for example, as a gasoline engine or a diesel engine.

The motor 3 comprises one or more cylinders 4, one of which is shown here. The cylinders 4 are supplied with pressurized (combustion) air by the ATL9. The ATL9 comprises a compressor 3 which is driven or operated via a shaft 14 of a turbine (exhaust gas turbine) 15 with a Variable Turbine Geometry (VTG). The turbine 15 is thus operatively connected/coupled with the compressor 13 via the shaft 14. The compressor 13 is arranged in the air line 5 to the motor 3 and the turbine 15 is arranged in the exhaust line 7 which discharges exhaust gases from the cylinders 4. Thus, the compressor 13 can be operated with the exhaust gas of the motor 3 in such a way that the turbine 15 is supplied with the exhaust gas from the motor 3 and is driven thereby. Further, the ATL9 is coupled with the control device 21.

The VTG is adjustable via an adjustment mechanism 17. A wastegate valve 19 is alternatively/additionally provided with respect to the VTG. Via the regulating mechanism 17 (and/or via the wastegate valve 19), the exhaust gas supplied to the turbine 15 and accordingly the power of the compressor 13 can be regulated. Alternatively, a multi-stage supercharging assembly may be provided. In other words, a plurality of ATLs 9 may be provided.

Further, the ATL9 has a motor 11. The electric machine 11 has a function as a motor and as a generator and is coupled/operatively connected to the shaft 14 of the ATL9. The electric machine 11 is designed in particular for measuring the rotational speed of the ATL9. Here, the rotation speed of the shaft 14, the rotation speed of the compressor 13, and/or the rotation speed of the turbine 15 may be represented by the rotation speed of the ATL9. Further, the motor 11 may be configured to apply torque to the ATL9. Thus, the rotational speed of the ATL9 may be increased and/or decreased via the motor 11. The control device 21 is coupled to the motor 11. Thereby, the motor 11 can be adjusted/controlled and the rotational speed of the ATL9 detected by the motor 11 can be read out. In other words, the rotational speed signal of the ATL9 detected by the motor 11 is processed by the control device 21.

In particular, the motor 11 may be integrated with the shaft 14. This is achieved, for example, in that the rotor (not shown) of the electric machine 11 is configured as part of the shaft 14, wherein the stator (not shown) of the electric machine 11 is arranged in a fixed position around the part of the shaft 14 configured as a rotor.

Fig. 2a and 2b show a static or dynamic rotational

speed control device

30,50 for the ATL9 of the motor 3. The static rotational speed control device 30 is active in the static operating state of the motor 3, while the dynamic rotational speed control device 50 is active in the dynamic operating state of the motor 3.

As is apparent from fig. 2a, the ATL actual rotational speed n _ATL,Ist ATL maximum rotation speed n _ATL,max (i.e. maximum allowable rotational speed of ATL, especially in view of structurePart damage), reserved speed zone n of ATL _ATL,Res And a setpoint value u calculated by the control device 21 for the actuating element (actuating mechanism 17 and/or wastegate valve 19) of the ATL9 _ATL,Soll,ECU Is an input parameter for the static rotational speed control device 30.

In this case, some of the input parameters arrive directly at the static rotational speed control device 30, for example the ATL actual rotational speed n _ATL,Ist Or is pre-processed/calculated, e.g. maximum allowable ATL speed n _ATL,max And a reserve rotational speed band n _ATL,Res . The static rotational speed control device 30 can generate a target torque M to be generated by the electric machine 11 _EM,Soll,stat And a setpoint value U for an ATL9 adjusting element _ATL,Soll As output parameters.

In block 29 it is checked whether the ATL actual rotational speed n _ATL,Ist Greater than the maximum rotation speed n at ATL _ATL,max And reserve speed zone n _ATL,Res The difference between them. The difference is formed in the summing point 27 by subtracting the reserved speed band n from the ATL maximum speed _ATL,Res . The difference corresponds to the virtual rotational speed range mentioned at the beginning of the ATL9, which corresponds to the (predetermined) permissible rotational speed range of the ATL9 determined by the control device 21. By means of the virtual rotational speed range of the ATL9, the ATL9 is thus blocked in view of its rotational speed, in particular upwards.

If the ATL actual rotation speed n _ATL,Ist Above this difference, the intervention signal I is known from block 29 _stat,1 . Otherwise, from block 29, it is known that the signal I is not interfered with _stat,0 . These two signals I _stat,1 And I _stat,0 Is used to determine whether a rotational speed adjustment device (EM adjustment device) 40 (described later) is activated or deactivated by means of the motor 11.

As is apparent from fig. 2b, the target boost pressure p calculated by the control device 21 _2,Soll Actual boost pressure p _2,Ist Limit pressure p _2,lim And the actual pressure p before the compressor _1,Ist Serving as an input parameter to the dynamic speed adjustment device 60. Here, the actual value p of the boost pressure _2,Ist And the actual pressure p before the compressor _1,Ist For example by correspondingly arranged (not shown) pressure sensorsAnd (3) detecting. Alternatively and/or additionally, a pressure value p can be derived therefrom _1,Ist And p _2,Ist Can be detected by a corresponding sensor (not shown) so that the control device 21 can determine the pressure value p _1,Ist And p _2,Ist . Depending on whether the dynamic speed control device 60 is active or inactive, the determined setpoint torque M (of the electric motor 11) is determined _EM,Soll,dyn Or motor zero moment M ₀ As output parameters, are known by the dynamic rotational speed control device 60. The dynamic adjustment device 60 is described in detail later.

Fig. 3a shows the thermodynamic regulating device 50 and EM regulating device 40 of the static rotational speed regulating device 30. Furthermore, the static rotational speed control device 30 has an activation block 31, in which it is determined whether the EM control device 40 is active. The activation block 31 is activated/invoked, provided that the intervention signal I _stat,1 Reaching the static rotational speed control device 30. The activation block 31 includes a two-point regulator 35 to exhibit a hysteresis-containing switching. The two-point regulator 35 has as input parameter the ATL actual rotational speed n _ATL,Ist . The upper switching point of the two-point regulator 35 is the ATL maximum rotation speed n _ATL,max And the down-switch point is at ATL maximum rotation speed n _ATL,max From a predetermined switching difference deltan _hys The difference between them. The lower switching point is determined in the summing point 33 in such a way that a predetermined switching difference deltan is to be determined _hys From ATL maximum rotation speed n _ATL,max Subtracting. Switching difference Deltan _hys Selected such that it is smaller than the reserve speed range n _ATL,res . Two-point regulator 35 outputs signal I _hys,1 When the ATL actual rotation speed n _ATL,Ist Beyond the upper switching point and output signal I _hys,0 When the ATL actual rotation speed n _ATL,Ist Below the lower switching point. If output signal I _hys,1 The EM conditioning device 40 acts. In contrast if the output signal I _hys,0 The thermodynamic regulating device 50 acts.

The EM conditioning device 40 is shown in detail in fig. 3 b. In the summing point 41, the ATL rotational speed adjustment deviation deltan _ATL Is determined in such a way that the ATL maximum rotational speed n _ATL,max Subtracting the ATL actual rotation speed n _ATL,Ist . The atl rotational speed control deviation Δn is controlled via a control device 43, which is embodied, for example, as a PI control device _ATL Is adjusted away (i.e., to a value of approximately "zero") by regulator 43 outputting an EM adjustment parameter u _EM Which adjusts the torque generated by the motor 11. EM adjustment parameter u _EM Is passed to a block 45 which illustrates that it depends on the EM adjustment parameter u _EM Is to be generated by the motor 11 _EM,u . When ATL rotation speed adjusts deviation delta n _ATL When positive, the EM regulating parameter u _EM Is determined by the regulator 43 in such a way that M _EM,u Is positive. The motor 11 thus operates such that the ATL rotation speed increases. When ATL rotation speed adjusts deviation delta n _ATL When negative, correspondingly generate negative M _EM,u With which the ATL rotational speed is reduced.

However, only negative regulation deviations should be regulated, i.e. the ATL rotational speed does not increase. This is achieved by block 47. Moment M dependent on EM tuning parameters _EM,u And zero moment M ₀ Serving as input parameters for block 47. In block 47, logic is acted upon which conveys only M _EM,Soll,stat As output parameter. It is thus ensured that only values less than or equal to zero produce the setpoint torque M as the motor 11 _EM,Soll,stat As output parameters from block 47 (and thus from EM adjustment device 40). In other words, the ATL rotational speed is only reduced, not increased, by the EM adjustment device 40 by means of block 47.

The thermodynamic regulating device 50 is shown in fig. 3 c. As mentioned above, the parameter I is output by the two-point switch (Zweipenktschalter) 35 _hys,0 When the thermodynamic regulating device 50 is active. In addition, when the non-interfering signal I has been previously output by the block 29 _stat,0 When the thermodynamic regulating device 50 is active.

In the thermodynamic control device 50, the ATL control element setpoint value u _ATL,Soll Based on the setpoint value u of the actuating element determined by the control device 21 _ATL,Soll,ECU And ATL rotational speed adjustment deviation Deltan _ATL To determine. Control unit setpoint value u determined by control unit 21 _ATL,Soll,ECU Can be driven by, for exampleThe driver expects to deduce. In particular, the driver expects to be realized by a corresponding torque of the motor 3, which in turn requires the target boost pressure p _2,Soll . Control element setpoint u determined by control device 21 _ATL,Soll,ECU The ATL9 is adjusted in such a way that the target boost pressure p is reached _2,Soll However, independent of the ATL rotational speed. The regulating element setpoint value u _ATL,Soll,ECU Thus acting as a pre-control value for the thermodynamic regulating device 50.

In the summing point 51, the ATL rotational speed adjustment deviation deltan _ATL Is determined (as described above). The regulator 55 (e.g., PI regulator) adjusts out the ATL rotational speed adjustment deviation deltan _ATL In such a way that the regulator determines an ATL regulating element setpoint u based on the regulator _ATL,Soll,Reg . In the summing point 53, the regulator-based ATL regulator element setpoint u _ATL,Soll,Reg And the setpoint value u of the actuating element determined by the control device 21 _ATL,Soll,ECU To settle accounts. Thus, the ATL control element setpoint value u is determined in the summing point 53 _ATL,Soll Which is an output parameter of the thermodynamic regulating device 50. Here, the settlement of the two nominal values is shown as subtraction. Addition in the summing point 53 is also conceivable, when the regulator 55 accordingly determines the regulator-based ATL regulating element setpoint u _ATL,Soll,Reg When (1).

By adjusting the element setpoint u by means of an ATL based regulator _ATL,Soll,Reg The pre-control value (i.e. the setpoint value u of the actuating element determined by the control device 21 _ATL,Soll,ECU ) Corrected by a factor such that the ATL actual rotational speed n _ATL,Ist Tracking maximum ATL rotational speed n _ATL,max . In particular, the pre-control value u _ATL,Soll,ECU Thus reducing the ATL rotational speed n by a certain offset (decrement) so as to attenuate the ATL rotational speed n as much as possible _ATL,max Overshoot of and the ATL actual rotation speed n _ATL,Ist Adjusted to the ATL maximum rotation speed n _ATL,max And (3) upper part.

The thermodynamic regulating device 50 works in parallel with the EM regulating device 40, wherein depending on the ATL rotational speed, either the former or the latter, i.e. its output parameters are used for rotational speed regulation of the ATL9. When generating signal I _hys,1 In the time-course of which the first and second contact surfaces,the EM regulating device 40 acts when generating signal I _stat,0 And I _hys,0 When the thermodynamic regulating device 50 is active. A high dynamic switching between the EM modulation device 40 and the thermodynamic modulation device 50 may thus be achieved.

The dynamic rotational speed control 60 of the ATL9 is shown in detail in fig. 4. In the division point 61, the rated pressure ratio p with respect to the compressor 13 _21,Soll Formed in such a way that the nominal boost pressure p _2,Soll Divided by the actual pressure p before the compressor 13 _1,Ist . In addition, the actual boost pressure p reached in block 63 _2,Ist Differentiated and output the actual boost pressure p _2,Ist Is a boost pressure gradient p _2,grad . For this purpose, the block 63 can be designed, for example, as a DT1 element. By means of a boost pressure gradient p _2,grad The delay in the boost pressure structure may be taken into account and predicted, for example, based on the inertia of the pre-compressed air present in the air line 5, the mass inertia of the ATL9 and/or the acceleration operation (Hochlaufen) of the ATL9.

Furthermore, by means of a boost pressure gradient p with respect to the

characteristic curve

65,87 _2,grad The intervention time t of the motor 11 can be determined _EM And rated moment M _EM,Soll,dyn . In this case, the intervention time t _EM Illustrating the generation of rated torque M by the motor 11 _EM,Soll,dyn How long or in other words how long torque interventions of the electric machine 11 for influencing the ATL rotational speed are to be carried out. Thus, the rated pressure ratio p with respect to the compressor 13 is utilized _21,Soll And a boost pressure gradient p _2,grad The intervention time t can be determined from the characteristic curve 65 _EM Or the nominal torque M is determined from the characteristic curve 87 _EM,Soll,dyn . The characteristic curve 87 is established by means of data determined empirically on a test stand, so that the mass inertia of the ATL9, in particular of its running wheels, can be taken into account and the acceleration operation of the ATL9 or the ATL rotational speed can be predicted. The setpoint torque M can thus be determined accordingly _EM,Soll,dyn It has to act on the ATL9 so as not to exceed the maximum ATL rotational speed n _ATL,max . In addition/alternatively to the characteristic curve 87, it is also possible to calculate the kinetic energy determination of the running wheel as a function of the ATL9 via a corresponding mass inertiaRated torque M _EM,Soll,dyn 。

In addition, in the dynamic rotational speed control device 60, it is determined whether rotational speed control should be effected by the electric motor 11. For this purpose, it is checked whether a dynamic operating state of the motor 3 is present. For this purpose, a boost pressure control deviation Δp is formed in the summation point 73 ₂ In such a way that the rated boost pressure p _2,Soll Subtracting the actual boost pressure p _2,Ist . The boost pressure adjustment deviation Δp ₂ In block 75, with a minimum pressure difference Δp ₂ Min. When the boost pressure adjusts the deviation deltap ₂ Exceeding a minimum pressure difference deltap of typically between 450 and 550mbar, e.g. 500mbar ₂ At min, there is a dynamic operation of the motor 3. For a minimum pressure difference deltap ₂ Other values or ranges of values for min are also possible.

It is also checked whether the limit pressure p is for an overshoot of the boost pressure p2 during the adjustment of the boost pressure _2,lim Is expected to be exceeded. In order to predict the boost pressure curve, the actual boost pressure p is in the summing point 67 _2,Ist With boost pressure gradient p _2,grad Loaded/added. The predicted boost pressure p is known from the summing point 67 _2,pred . Next, the desired boost pressure p is set in the summing point 67 _2,Soll Subtracting the predicted boost pressure p _2,pred Thereby determining a predicted boost pressure adjustment deviation Δp _2,pred . In block 71 it is checked whether the predicted boost pressure adjustment deviation Δp is present _2,pred Exceeding the limit pressure p for boost pressure overshoot _2,lim 。

In order for the dynamic speed control device 60 to output an intervention signal I _dyn,1 Two conditions have to be met. It is therefore necessary to know from block 71 that the predicted boost pressure adjustment deviation Δp _2,pred Greater than the limit pressure p for boost pressure overshoot _2,lim . It is also known from block 75 that the boost pressure control deviation Δp ₂ Greater than a minimum pressure differential Δp ₂ And (5) min. If both conditions are met, block 77 outputs an intervention signal I _dyn,1 And otherwise output a "do not interfere" signal I _dyn,0 。

When the block 71 outputs the intervention signal I _dyn,1 In the event that the intervention signal is transmitted to a block 79, the block 79 additionally receives the intervention time t on the input side _EM . In block 79 it is determined whether the intervention signal I _dyn,1 At the intervention time t _EM The inner is output by block 77. If so, block 79 outputs an intervention signal I _dyn,1 And otherwise output a "do not interfere" signal I _dyn,0 。

If the intervention signal I is known from a dynamic speed control device _dyn,1 The motor 11 is operated in such a way that a corresponding setpoint torque M is produced _EM,Soll,dyn And thereby affects the ATL rotational speed. However if it is known that the signal I is "not intervening _dyn,0 Output motor zero moment M ₀ And the motor 11 is not operated. In other words, the motor 11 does not affect the ATL rotation speed.

If there is a "do not interfere" signal I _dyn,0 The static rotational speed control device 30 in turn acts in parallel with the dynamic control device 60. Likewise, the parallel operation of the static control device 30 and the dynamic control device 60 again makes it possible to use the signal I between them _dyn,1 ,I _dyn,0 Is a high dynamic "switching".

Fig. 5a shows the nominal and actual boost pressure p during the stationary operating state of the motor 3 _2,Soll ,p _2,Ist And sum for nominal and actual ATL rotational speeds n _ATL,Soll ,n _ATL,Ist In terms of curves. These curves are plotted against time. Rated boost pressure p _2,Soll Shown by the horizontal line, the actual boost pressure p _2,Ist In particular, generally wave-like around the horizontal line. However, the actual boost pressure p _2,Ist Is roughly adjusted. Actual ATL speed n _ATL,Ist The curve of (2) likewise and in particular generally fluctuates in a wave-like manner. Furthermore, the maximum allowable ATL speed n is also shown in view of the ATL speed _ATL,max And a reserve rotational speed band n _ATL,Res 。

Fig. 5a shows a curve in which the above-mentioned static rotational speed control device 30 has not yet been tampered with, and in particular illustrates in which time periods EM control takes placeThe device 40 or the thermodynamic regulating device 50 should function. Such a period of time may be in the range of one tenth of a second, for example. In this case, when the actual ATL rotational speed is in the reserve rotational speed range n _ATL,Res When the thermodynamic regulating device 50 is active. If the actual ATL rotational speed n _ATL,Ist In contrast, in the reserve rotational speed range n _ATL,Res Above that, the EM modulation device 40 is active.

Fig. 5b shows the nominal and actual boost pressure p during dynamic operating states of the motor 3 _2,Soll ,p _2,Ist And sum for nominal and actual ATL rotational speeds n _ATL,Soll ,n _ATL,Ist In terms of curves. Furthermore, a setpoint torque M to be generated by the electric machine 11 is shown _EM,Soll,dyn Is a curve of (2). Rated moment M _EM,Soll,dyn Thus rise to act on the ATL actual rotation speed n in such a way _ATL,Ist So that the ATL actual rotation speed does not exceed the maximum ATL rotation speed n in the case of ATL acceleration running _ATL,max 。

List of reference numerals:

1. motor vehicle

3. Internal combustion engine (Motor)

4. Cylinder

5. Air line (gas path)

7. Waste gas circuit (waste gas path)

9. Exhaust gas turbocharger (ATL)

11. Motor with a motor housing

13. Compressor with a compressor body having a rotor with a rotor shaft

14. Shaft

15. Turbine engine

17. Adjusting mechanism for VTG

19. Waste gas bypass valve

21. Control device

27. Summing point

29. Comparison block

30. Static adjusting device

33. Summing point

35. Two-point switcher

40. Adjusting device by motor

43. Square box (e.g. PI regulator)

45,47 square frame

50. Thermodynamic regulating device

53. Summing point

55. Square box (e.g. PI regulator)

60. Dynamic adjusting device

61. Dividing point

63. Square box (e.g. DT element)

65. Characteristic curve

67,69 summing point

71. Square frame

73. Summing point

75,77,79 square frames

87. Characteristic curve

n _ATL,Ist ATL actual rotation speed

n _ATL,max Maximum allowable ATL rotational speed

n _ATL,Res ATL reserve rotational speed belt

Δn _ATL ATL rotational speed adjustment deviation

u _ATL,Soll,ECU Nominal value calculated by the control device 21 for an ATL regulating element

u _ATL,Soll,Reg Regulator-based setpoint for ATL control elements

u _ATL,Soll ATL regulating element setpoint

u _EM Adjusting parameters for an electric machine

I _dyn,1 Intervention signal from dynamic adjustment device

I _dyn,0 "no intervention" signal from dynamic adjustment device

I _hys,1 Signals from two-point switches

I _hys,0 Signals from two-point switches

I _stat,1 Intervention signal from static adjustment device

I _stat,0 "no intervention" signal from a static adjustment device

M _EM,Soll,dyn Rated torque of an electric machine from a dynamic control device

M _EM,Soll,stat Rated torque of an electric machine from a static control device

M _EM,u (Motor) torque

p _1,Ist Actual pressure of compressor

p _2,grad Pressure gradient of boost

p _2,Ist Actual boost pressure

p _2,lim Extreme pressure for overshoot

p _2,lim Minimum pressure difference

p _2,Soll Rated boost pressure

p _21,Soll For nominal values of pressure ratio via compressor

Δp ₂ Deviation of boost pressure adjustment

Δp _2,pred Predicted boost pressure regulation deviation

t _em Duration of intervention.

Claims

1. A method for operating an exhaust gas turbocharger (9) of an internal combustion engine (3), wherein the exhaust gas turbocharger (9) is operatively connected to an electric motor (11) and the rotational speed of the exhaust gas turbocharger (9) can be adjusted via the electric motor (11), the method comprising:

-determining a static or dynamic operating state of the internal combustion engine (3); and

-reducing the actual speed (n) of the exhaust gas turbocharger via said electric machine (11) _ATL,Ist ) In order to comply with an upper rotational speed limit (n) of the exhaust gas turbocharger (9) _ATL,max ) Wherein the electric machine (11) is operated as a function of the operating state of the internal combustion engine (3), wherein the electric machine (11) is controlled via a first control device (30) when a static operating state is present and via a second control device (60) when a dynamic operating state is present, wherein the first control device (30) has a control device for reducing the actual rotational speed (n) of the exhaust gas turbocharger _ATL,Ist ) A first adjustment part (40) and a second adjustment part (50), wherein the first and second adjustment parts (40, 50) are dependent onIn the actual speed (n) _ATL,Ist ) And the actual rotational speed (n) of the exhaust gas turbocharger _ATL,Ist ) Is effective in the hysteresis characteristic of the battery.

2. Method according to claim 1, characterized in that the upper rotational speed limit (n _ATL,max ) Is a control parameter of the first and second regulating members (40, 50).

3. Method according to any of the preceding claims, characterized in that the electric machine (11) is operable in a dynamic operating state of the internal combustion engine (3) in dependence on the mass inertia of the exhaust gas turbocharger (9) and/or the inertia of a boost pressure structure.

4. A method according to claim 3, characterized in that the mass inertia of the exhaust gas turbocharger (9) and the inertia of the charging pressure structure are taken into account by means of a characteristic curve (65,87).

5. The method according to any one of claims 1 to 2, characterized in that when the boost pressure adjustment deviation (Δp ₂ ) Is greater than a predetermined minimum pressure difference (deltap ₂ Min) and a predicted boost pressure regulation deviation (Δp) _2,pred ) Greater than a predetermined limit pressure (p _2,lim ) When there is a dynamic operating state of the internal combustion engine (3).

6. The method according to claim 5, characterized in that when the boost pressure adjustment deviation (Δp ₂ ) Less than a predetermined minimum pressure difference (Δp ₂ Min) and/or the predicted boost pressure regulation deviation (Δp) _2,pred ) Less than the predetermined limit pressure (p _2,lim ) When there is a static operating state of the internal combustion engine (3).

7. The method of claim 6, wherein the predicted boost pressureForce adjustment deviation (Δp) _2,pred ) Depending on the boost pressure gradient (p _2,grad ) To be measured.

8. Method according to any of claims 1-2, characterized in that the actual speed (n _ATL,Ist ) Can be detected via the motor (11).

9. Method according to any of claims 1-2, characterized in that the actual speed (n _ATL,Ist ) In such a way that the moment (M _EM,Soll,stat ,M _EM,Soll,dyn ) Is produced by the electric motor (11) and acts on the shaft (14) of the exhaust gas turbocharger (9).

10. Method according to any one of claims 1 to 2, characterized in that the exhaust gas turbocharger (9) has an adjusting assembly (17, 19) and that the exhaust gas turbocharger actual rotational speed (n) is achieved via the electric machine (11) when the adjusting device (17, 19) is adjusted in the open limit position _ATL,Ist ) Is reduced.

11. The method according to claim 10, characterized in that the adjusting assembly (17, 19) is a variable turbine geometry (17) and/or a wastegate valve (19).

12. A control device (21) for an exhaust gas turbocharger (9) of an internal combustion engine (3), wherein the control device (21) is provided for carrying out the method according to any one of the preceding claims.

13. An internal combustion engine (3) with an exhaust gas turbocharger (9) and a control device (21) as claimed in claim 12.

14. A motor vehicle (1) with an internal combustion engine (3) according to claim 13.