DE102012006532A1 - Method for controlling electrical actuator for waste-gate valve arrangement of supercharger of internal combustion engine of motor car, involves monitoring position of gates during operation of engine with closed gates by hot position value - Google Patents

Abstract

The method involves determining a closing position of waste-gates (21) as a cold position value before operation start of an internal combustion engine (1) according to the operation start during a load request of the internal combustion engine. The waste-gates are closed with a closing force. The resulted closing position of the waste-gates is detected as a hot position value, and the position of the waste-gates is monitored during operation of the internal combustion engine with the closed waste-gates by the hot position value. An independent claim is also included for a device for controlling an electrical actuator for a waste-gate valve arrangement of a supercharger of an internal combustion engine.

Description

The invention relates to a method for controlling an electric actuator for a wastegate valve arrangement of an exhaust gas turbocharger of an internal combustion engine and to an apparatus for carrying out the method according to the invention.

It is generally known in exhaust gas turbochargers of internal combustion engines by using a so-called wastegate perform a charge air control. In a wastegate of a wastegate valve assembly is usually a simple flap, by means of which the amount of an exhaust gas stream flowing through the exhaust gas turbine of an exhaust gas turbocharger is controlled by means of an electric actuator. Such actuators are connected via a guided from a housing linkage or push rod with the wastegate. To maintain the closed position of the wastegate, values of up to about 250 N may be required for such actuators in the boom. These forces must be permanently provided to reliably hold the wastegate in the closed position so that the wastegate remains tight despite the exhaust countervailing forces.

From the DE 10 2008 051 818 A1 a method for controlling a arranged in a bypass duct for a turbine of an exhaust gas turbocharger wastegate by means of an electric actuator is known in which an exhaust gas stream of an internal combustion engine over the bypass channel by opening or closing the wastegate can be bypassed by the turbine or completely routed to the turbine. When a load request to the internal combustion engine, the wastegate is closed and pressed with a predetermined first force against a wastegate valve seat, said predetermined first force is selected such that against the exhaust pressure of the internal combustion engine during the load request and at least until reaching a desired torque of the Bypass channel remains closed flow-tight.

Further, it is provided in this known method that in a partial load operation of the internal combustion engine, the wastegate is closed and pressed with a predetermined second force against the wastegate valve seat, wherein the predetermined second force is smaller than the predetermined first force. The predetermined first force is generated by energizing the electric actuator with a maximum holding current. The reduction of this holding force, which determines the first force, to a second lower value serves for the overheating protection of the servomotor of the electric actuator.

In this known method, a specific closing force is generated at the wastegate with preset current values of the electric motor of the electric actuator, wherein the higher value is generated at a load request or transient operating behavior of the internal combustion engine and the lower value at partial load. The disadvantage, however, is that the higher value must be selected so that under all operating conditions of the bypass channel is tightly closed by the wastegate, especially in transient operation of the engine, ie during an acceleration process or rapid load changes in which occurring by pressure pulsations of Exhaust gas, the wastegate can be briefly pressed. It follows that even under operating conditions, under which would be sufficient to close the wastegate tight force required by lower current values, the servomotor is unnecessarily applied to then too high maximum or possibly also too high force level.

Since actuators for wastegates in their push rods forces well over 250 N can be achieved, there is a risk that at a constant closing force, as the method according to the DE 10 2008 051 818 A1 suggests such forces lead to damage to the exhaust gas turbocharger or its housing and increased wear, as, for example. In an actuatable via a push rod wastegate the actuating forces generated in this push rod lead to reaction forces in the housing of the exhaust gas turbocharger.

Furthermore, the describes DE 10 2009 028 117 A1 a method for operating an electric actuator for a wastegate actuator of an exhaust gas turbocharger, in which a wastegate with the aid of the actuator is electrically adjustable and arranged in an exhaust line of an internal combustion engine, wherein depending on an open position of the wastegate, the exhaust gas turbocharger flowing through the exhaust gas quantity is adjustable. In this method, the actuator is energized with an electric current during a closed position of the wastegate, such that a varying closing force is generated according to the course of an applied over the wastegate exhaust back pressure. In this case, the actuator can be controlled so that the closing force over time substantially proportional or offset in time is proportional to the exhaust back pressure. Since the time profile of the exhaust backpressure depends on the crankshaft position of a crankshaft of the internal combustion engine, the actuator is energized depending on the crankshaft position to maintain the closed position of the wastegate.

Also in this known method, it is not excluded that occurring in the closed state of the wastegate pressure pulsations of the exhaust gas flow can cause damage to the wastegate or the housing of the exhaust gas turbocharger.

Against this background, it is the object of the invention to provide a method for controlling an electric actuator for a wastegate valve assembly of an exhaust gas turbocharger of an internal combustion engine, in which the wastegate is acted upon by closing forces that are optimally adapted to the exhaust pressures occurring in all operating conditions, without that damage to the wastegate or the housing of the exhaust gas turbocharger occur. It is another object of the invention to provide a device for carrying out the method according to the invention.

The first object is achieved by a method having the features of patent claim 1.

This inventive method for controlling an electric actuator for a wastegate valve assembly of an exhaust gas turbocharger of an internal combustion engine, in which a arranged in a bypass duct of the exhaust gas turbocharger wastegate is closed or opened by means of the actuator for adjusting the past the bypass duct on the exhaust gas turbocharger exhaust gas flow is, that before starting operation of the internal combustion engine, at least the closed position of the wastegate is determined as a cold position value, after start of operation at a load request of the internal combustion engine, the wastegate is acted upon closing with a first closing force and the closed position of the wastegate is detected as a warm position value and during the subsequent operation of the internal combustion engine closed wastegate by means of the warm position value, the position of the wastegate is monitored.

It has been recognized that by monitoring the temperature and force induced deformation of the wastegate, the control of the wastegate can be significantly improved, so that it is possible to avoid essentially mechanical damage to the wastegate or the housing of the exhaust gas turbocharger and in particular the wear and the susceptibility of the system Wastegate valve assembly and exhaust gas turbocharger can be significantly reduced.

A possible temperature-induced deformation of the wastegate is detected and monitored by first before the start of operation of the internal combustion engine, before the start of the wastegate is acted upon by a correspondingly low closing force and, for example. By means of a position sensor, a position value in the closed position of the wastegate, the so-called cold position value is detected. After the start of operation, the wastegate is acted upon in its closed position with a first closing force and thereby also the position value, called hot position value, detected by means of the position sensor, in particular detected a relation to the cold position value changed position value. With this warm position value, therefore, with further closed state of the wastegate, its further temperature or wear-related deformations can be monitored by detecting the position values of the wastegate and, if appropriate, suitable countermeasures can be initiated if the deformations are too great.

The monitoring of the closed wastegate is carried out according to a development of the invention in that a threshold value is determined as a function of the hot position value and when exceeding this threshold value by a position value of the wastegate, the closing force causing this position value is reduced. This prevents permanent damage to the wastegate.

In one embodiment of the invention, the first closing force used to determine the hot position value of the wastegate is less than the second closing force generated for acting on the wastegate during operation of the internal combustion engine. This ensures that a closing force is generated for determining the hot position of the wastegate, in which a deformation due to the closing force is reliably avoided.

According to a further embodiment of the invention, if the wastegate is acted upon by using the cold-position value in such a manner with a closing force damping the closing movement, then the wastegate executes a gentle closing movement into the closed position. This prevents a rapid and hard impact of the wastegate in its closed position, since during normal operation, from which the detection of the hot position value is carried out, the wastegate can be subject to high dynamics. By this gentle closing movement into the closed position, a warm position value is obtained with high accuracy. Preferably, it is provided to act upon the wastegate after being acted upon by the damping closing force with the first closing force.

It is particularly advantageous if the determination of the hot-position value is carried out continuously during the operation of the internal combustion engine is, and always when the wastegate is controlled from an open position to its closed position, so that the wastegate first with the closing force damping closing force, then in the closed position with the first closing force to determine if a changed position value is present as a warm position value and finally is acted upon by the second closing force to monitor in the acted upon by this second closing force state of the wastegate whose deformations. With changed warm position values, therefore, the previous values are successively replaced by the newly detected warm position values in order to ensure a long service life of the wastegate or the wastegate valve arrangement.

Furthermore, according to an embodiment of the invention, it is also advantageous if not only the cold position value of the closed position, but also the open position of the wastegate, for example, to be detected by means of a position sensor as a cold position value of the open position prior to start of operation. With such a value, a diagnostic function regarding the function of the wastegate can be performed.

It also makes sense to act upon opening of the engine, the wastegate to open with a third closing force and thereby to detect the resulting open position of the wastegate as a warm position value of the open position, for example. By means of a position sensor. This further improves the diagnostic function with such a warm position value.

According to one embodiment of the invention, the second closing force is regulated to a closing force set value as a function of a closing force actual value or to a desired value of an operating parameter of the actuating drive determining the closing force as a function of an actual value of this operating parameter. Thus, either the closing force itself as a control variable or instead of the closing force, a closing force determining operating parameters of the actuator, preferably the operating current is used as a controlled variable. Thus, such a regulation of the closing force can be realized simply and inexpensively by means of such an operating parameter of the actuator.

This not only prevents damaging deformation of the wastegate, but at the same time keeps the closing force at the correct value through this control.

Thus, each change in the exhaust gas pressure also leads to a change in the closing force actual value and thus to a renewed adjustment of the closing force to the desired value, so that in the closed state of the wastegate the required tightness over all operating conditions of the internal combustion engine, even when occurring over the service life signs of wear becomes. Due to the ensured tightness over the entire operating range, the torque behavior of the internal combustion engine is improved in the lower speed range. Furthermore, damage to the exhaust-gas turbocharger and the wastegate is largely avoided by the constantly controlled closing force on the wastegate and the monitoring of its deformation.

Preferably, even when the threshold value is exceeded by a position value of the wastegate, the closing force setpoint value or the setpoint value of the operating parameter of the actuating drive is reduced and the closing force is adjusted to the lower value.

Furthermore, according to a development of the invention, it makes sense to determine the closing force actual value by means of a force sensor, whereby a constructively simple to implement solution is given.

A cost-effective solution for providing a closing force actual value is a further development of the invention, in which, in the case of using the operating current of the drive unit as a controlled variable, the closing force actual value from the operating current and the temperature of the actuator is estimated by means of a computer model. A force sensor is therefore not required. It is preferably provided to additionally include the position of the wastegate in the computer model so that the two states "open wastegate" and "closed wastegate" can each be realized with the correct closing force.

To carry out the control, a control deviation is determined from the closing force set value and the determined closing force actual value and supplied to a closing force regulator for generating the control signals for controlling the actuating drive.

When using the operating current as a controlled variable is determined from a closing force setpoint depending on the position of the wastegate and the operating temperature of the actuator by means of a computing model, an operating current setpoint and determined by comparison with an operating current actual value, a control deviation, which a Closing force regulator for generating control signals for controlling the actuator is supplied.

The second-mentioned object is achieved by a device having the features of patent claim 15.

This device for controlling an electric actuator for a wastegate valve assembly of an exhaust gas turbocharger of an internal combustion engine with a arranged in a bypass duct of the exhaust gas turbocharger wastegate, which is closed or opened by means of the actuator for adjusting the bypass channel past the exhaust gas turbocharger exhaust stream, characterized by characterized in that the device is designed to determine at least the closed position of the wastegate as a cold position value after start of operation at a load request of the internal combustion engine to apply a first closing force to the wastegate and to detect the closed position of the wastegate as a hot position value and during the subsequent operation of the internal combustion engine with closed wastegate by means of the warm position value to monitor the position of the wastegate.

Such a device can be easily integrated into an existing electronic engine control of the internal combustion engine in a motor vehicle.

In further embodiments, it may be provided:
A device for controlling an electric actuator for a wastegate valve assembly of an exhaust gas turbocharger of an internal combustion engine, comprising means for closing or opening a arranged in a bypass duct of the exhaust gas turbocharger wastegate by means of the actuator for adjusting the bypass channel past the exhaust gas turbocharger exhaust stream, with means for determining at least the closed position of the wastegate as a cold position value before the start of operation of the internal combustion engine, with means for applying the wastegate at a load request of the internal combustion engine after start of operation with a first closing force for closing and means for detecting the thereby effected closed position of the wastegate as a warm position value and means for monitoring the Position of the wastegate with closed wastegate by means of the warm position value during the subsequent operation of the internal combustion engine.

A device with means for determining a threshold value as a function of the hot position value and for reducing the closing force which brings about this position value when this threshold value is exceeded by a position value of the wastegate.

An apparatus comprising means for determining the warm position value and for applying to the wastegate a closing force damping the closing movement using the cold position value so that the wastegate performs a gentle closing movement to the closed position.

A device with means for acting on the wastegate with the first closing force after exposure to the damping closing force.

A device with means for applying the wastegate during operation of the internal combustion engine at each control of the wastegate from an open position in its closed position, first with the closing force damping closing force, then with the first closing force and finally with the second closing force.

A device with means for determining next to the closed position and the open position of the wastegate as a cold position value of the open position before the start of operation of the internal combustion engine.

A device with means for applying the wastegate after the start of operation of the internal combustion engine for opening with a third closing force and for determining the thereby caused open position of the wastegate as a warm position value of the open position.

A device with means for controlling the second closing force to a closing force target value as a function of a closing force actual value or to a target value of the closing force determining operating parameter of the actuator in dependence on an actual value of this operating parameter.

A device with means for reducing the closing force setpoint or the setpoint of the operating parameter of the actuator when the threshold value is exceeded by a position value of the wastegate.

A device with means for determining the closing force actual value by means of a force sensor.

A device having means estimating the closing force actual value from the operating current and the operating temperature of the actuator and preferably from the position of the wastegate determined by means of a position sensor by means of a computer model.

A device with means for determining a control deviation from the closing force target value and the determined closing force actual value and for supplying the determined control deviation to a closing force controller for generating control signals for controlling the actuator.

A device in which as the closing force determining operating parameters of the operating current the actuator is used with means for determining an operating current setpoint from a closing force setpoint value as a function of the position of the wastegate determined by a position sensor and the operating temperature of the actuator by means of a computer model and with means for determining a control deviation by comparison with an operating current actual value, which is supplied to a closing force controller for generating control signals for controlling the actuator.

The invention will be described below in detail by means of embodiments with reference to the accompanying figures. Show it:

1 a schematic representation of an internal combustion engine with an exhaust gas turbocharger according to the invention;

2 a block diagram of an actuator with drive circuit as an embodiment of the method according to the invention;

3 a diagram showing the course of the closing force on a wastegate and the course of the associated position values to explain the method according to the invention;

4 a further diagram for illustrating the course of the closing force on a wastegate and the course of the associated position values for explaining the method according to the invention; and

5 a block diagram of an actuator with drive circuit as a further embodiment of the method according to the invention;

The internal combustion engine 1 to 1 indicates a cylinder with a combustion chamber hinted 3 and an intake and exhaust valve. The exhaust gas flow 4a from the combustion chamber 3 is by means of an exhaust pipe 4 over a turbine 2a an exhaust gas turbocharger 2 passed, which with a compressor wheel 2 B connected via a fresh air duct 5 by means of a fresh air filter 13 filtered fresh air is supplied for compression. The compressed air is from an outlet of the compressor 2 B via a charge air cooler 8th and a throttle 7 the combustion chamber 3 fed. Further, on the compressor side of the exhaust gas turbocharger 2 a recirculation valve 10 arranged, which prevents when closing the throttle 7 compressed air in the compressor housing of the exhaust gas turbocharger 2 recoils and there the compressor wheel 2 B slows down, causing damage to the turbocharger 2 could lead.

Further, between the throttle 7 and the inlet valve of the combustion chamber 3 a boost pressure sensor 6 arranged, the measuring signals is fed to an engine control unit. Likewise, the measuring signals of an air mass sensor 9 fed to this engine control unit.

On the turbine side of the exhaust gas turbocharger 2 indicates the exhaust pipe 4 a bypass channel 11 on, by means of a wastegate 21 having bypass valve assembly 20 can be opened or closed, so that in the open state of the wastegate 21 a part of the exhaust gas flow 4a at the turbine 2a can be bypassed to get through with the turbine 2a directed exhaust gas stream to reunite before the entire exhaust stream 4a through a catalyst 12 is directed.

The bypass valve assembly 20 is from an actuator 30 operated, in turn, from a control unit 40 is controlled.

The method of controlling the bypass valve arrangement 20 will be described below on the basis of 2 . 3 and 4 explained.

According to 2 includes the actuator 30 an electric motor 31 acting as a linear drive via a push rod 32 the wastegate 21 the bypass valve assembly 21 pressed, so from a bypass channel 11 closing closed state in a bypass channel 11 released open state and vice versa. Furthermore, this actuator has 30 one the position of the wastegate 21 detecting position sensor 33 and a force sensor 34 on which, for example, by means of a strain gauge on the push rod 32 by the torque of the electric motor 31 generated, on the wastegate 21 measures acting closing force.

The measured values of the position sensor 33 and the force sensor 34 are in a double diagram according to 3 with the position values Pos _{act of} the wastegate plotted over the time t 21 and at the wastegate 21 acting closing force values F _act , wherein the position values Pos _act of the position sensor 33 and the closing force values F _act of the force sensor 34 be generated.

The electric motor 31 of the actuator 30 is from a driver circuit 41 the control unit 40 according to 2 controlled by a PWM signal U _PWM , which is the motor voltage of the electric motor 31 represents. This is the driver circuit 41 constructed by means of semiconductor switches in H-bridge circuit. The measuring signal of the position sensor 33 , the open or closed state of the wastegate 21 is displayed to a positioner 42 fed. The current closing force F _act indicating Measuring signal of the force sensor 34 uses a closing force regulator 45 the control unit 40 , Finally, the control unit points 40 another diagnostic unit 43 on.

The driver circuit 41 is powered by a battery voltage U _{Batt of} a vehicle electrical system.

The closing force regulator 45 is part of a control loop for regulating the closing force F of the wastegate 21 as a control variable, this control loop includes as controller this closing force regulator 45 , as actuator, the driver circuit 41 together with the electric motor 31 and as a controlled system, the bypass valve assembly 20 with the wastegate 21 and as feedback of the current closing force F _act as the closing force actual value to the closing force controller 45 the force sensor 34 , The control of the control unit 40 done by an engine control unit 60 ,

Before the start of the internal combustion engine 1 when, for example, the ignition key of an ignition switch is operated, the wastegate 21 according to the in 3 Phase A represented by corresponding parameter specifications of the engine control unit 60 to the control unit 40 controlled.

In this phase A becomes the wastegate 21 initially in its open position and then controlled in its closed position and the means of the position sensor 33 detected position values Pos _co and Pos _cc as cold position values in the engine control unit 60 stored, the position value Pos _co as a cold position value for the open position and the position value Pos _cc as a cold position value for the closed position of the wastegate 21 ,

To carry out this phase A, a sequence of different closing force values of the closing force F is generated, so that a progression of the closing force F _act corresponding to the curve K _{F_c in} accordance with _FIG 3 results. After that, first with a closing force value F _c1 the wastegate 21 moved in its open position, then the closing force is increased in stages over the value of zero to the closing force value F _c2 , whereby the wastegate 21 is pressed in its closed position. The movement of the wastegate 21 In this phase A takes place linearly as a function of the force values, since the internal combustion engine 1 not yet started and therefore no exhaust gas flow to the wastegate 21 acts.

After starting the engine goes 1 in their normal operation, according to the diagram 3 is represented as phase B, which with a possible course of motion of the wastegate 21 is shown as curve K _{pos_w} . The interaction of the exhaust pressure of the exhaust stream 4a with the acted upon by a closing force wastegate 21 no longer leads to a linear behavior of the position values POS _{act of} the wastegate 21 ,

Lies to the engine control unit 60 a load request, which is a control of the wastegate 21 required in the closed position, generates the engine control unit 60 initially control parameters for the control unit 40 for controlling the wastegate 21 according to a phase C after 3 ,

In this phase C, a profile of the closing force F is generated, so that the wastegate 21 a soft closing movement (soff landing) in the closed position of the cold position value Pos _cc performs. According to the curve K _{F_w of} the closing force F _act , the phase C starts with a closing force value F _w0 , which linearly changes to the value zero, before it is increased substantially abruptly to a first closing force _value F _w1 . The Kure K _{pos_w of} the position _values shows in this phase C that the position values gradually approach the cold position value Pos _cc .

The closing force increased in the subsequent phase D to the first closing force _value F _w1 serves for a possible change in the position of the wastegate 21 due to the heat effect of the exhaust gas flow 4a to detect. Such a new position is called warm position value Pos _wc the closed position of the wastegate 21 detected and in the engine control unit 60 stored. In the subsequent to the phase D phase E is the internal combustion engine 1 operated with the corresponding parameters present in their usual way, with the closing force is increased to a normal operating second closing force _value F _w2 of about 250 N. The upstream phases C and D do not adversely affect the performance of the internal combustion engine 1 because these phases C and D are executed only when there are conditions conducive to control of the wastegate 21 lead in its closed position.

In phase E, the deformations due to temperature, force or wear are monitored by detecting the position values Pos _act . For this purpose, depending on the hot position value Pos _wc, a threshold Pos _{s is} determined, with which the current position value Pos _{act is} constantly compared. In the diagram after 3 In this phase D, the curve K _{F_w runs} the position _values Pos _{1 of} the wastegate 21 below this threshold Pos _s , so that the example occurring at time t ₁ deformation P1 is acceptable.

The threshold Pos _s is determined experimentally as a function of the warm position value Pos _wc and as a map in the engine control unit 60 stored.

The closing force F generated in this phase E with the second closing force _value F _w2 is adjusted to a desired value by means of the control circuit explained above.

For this purpose, the closing force setpoint is the closing force F at the wastegate 21 from the engine control unit 60 a second clamping force value F generated _w2 corresponding closing force command value F _req and the closing force controller 45 fed. This closing force setpoint F _req is dependent on the measured value of the air mass sensor 1 (see. 1 ) and possibly in dependence of the speed of the internal combustion engine 1 by means of one in the control unit 60 determined map determined. From this closing force setpoint F _req and the closing force actual value F _act is by means of the closing force regulator 45 formed a control deviation and from this a control signal S _F generated, which with one of the positioner 42 generated control signal S _Pos rounded (sum element 44 ) and the driver circuit 41 is supplied, which therefrom a voltage signal, that is, the PWM signal U _PWM as a control variable for the electric motor 31 generates, so that the corresponding torque a closing force F with the second closing force _value F _w2 on the wastegate 21 causes.

With this regulation of the closing force F of the wastegate 21 to a predetermined closing force setpoint F _req the closing force F is continuously monitored and possibly readjusted, not only when the operating conditions change, but in particular by the exhaust gas flow 4a caused pressure conditions on the wastegate 21 to change.

As explained above in connection with the description of phase E, there remains the deformation of the wastegate 21 in the frame given by the threshold Pos _s . The diagram after 4 shows a phase E, in which at a time t _2, the position values Pos _act of Wastegate 21 exceed the threshold Pos _s with a maximum position value Pos ₂ and there a deformation P2 of the wastegate 21 show that is no longer acceptable. To damage the wastegate 21 to reduce P2 by such a deformation, the second closing force with the closing force _value F _{w2 is lowered} to a closing force _value F _w22 of, for example, 200 N. As a result, the position values Pos _{act of} the wastegate fall 21 with a position value Pos ₃ again below the threshold pose.

Also in this embodiment according to 4 Before phase E, phases C and D are carried out as described in connection with 3 were explained.

These phases C and D are during operation of the internal combustion engine 1 always done when the wastegate 21 is controlled from an open position to its closed position. This constantly changes the current mechanical state of the wastegate 21 Imaging hot position Pos _wc determined so that temperature and wear induced deformations during phase E over the life of the system exhaust gas turbocharger 2 and wastegate valve assembly 20 can be detected and damage to this system can be avoided, whereby a long life or service life of the components involved is achieved.

According to the 3 and 4 can for the wastegate 21 Also, a hot position value Pos _where for its open position in the phases C and D are determined with appropriately adjusted closing force values, which for diagnostic purposes with regard to the function of the wastegate 21 can be used.

The 5 shows a further embodiment, which is opposite to that after 2 in it different that the actuator 30 instead of a force sensor, a temperature sensor detecting the operating temperature T _act 35 and the control unit 40 additionally a closing force estimation unit 46 having. With this closing force estimation unit 46 is based on the operating parameters operating current l _act and operating temperature T _{act of} the actuator 30 , so the electric motor 31 the actual closing force F _{act_est_ is estimated} as an actual value by means of a mathematical model.

According to this embodiment 5 is also by means of a control loop, the closing force F at the wastegate 21 regulated to a desired value, in contrast to the embodiment according to 2 the feedback of the controlled variable via the temperature sensor 35 and the closing force estimation unit 46 on the closing force regulator 45 he follows.

Also in this embodiment according to 5 the phases A to E are carried out. Instead of using the force sensor 34 detected size F _act occurs in the diagram according to the 3 and 4 the estimated size F _{act_est} . According to another embodiment, not shown, instead of the closing force F as a controlled variable of the operating _current I _{act of} the electric motor 31 governed by a closing force setpoint F _req in response to the means of the position _sensor 33 certain position Pos _act of Wastegate 21 and by means of a temperature sensor 35 determined operating temperature T _{act of} the actuator 30 by means of a calculation model, an operating current target value I _req is determined and by comparison with the current operating current l _act as the operating current actual value I _is a control deviation is determined, which also a closing force controller 45 for generating control signals S _F for controlling the actuator 30 is supplied. In such an embodiment, the different closing force values become effective the phases A to E via the operating _current I _{act of} the electric motor 31 set.

Finally, it is also possible, the operating temperature of the electric motor 31 indirectly, not by means of a temperature sensor 35 to determine, but, for example, by means of the operating parameters motor voltage U _PMW , the battery voltage U _B and the operating _current I _{act of} the electric motor 31 with the help of a mathematical model.

LIST OF REFERENCE NUMBERS

1

Internal combustion engine

2

Exhaust gas turbocharger of the internal combustion engine 1

2a

Turbine of the exhaust gas turbocharger 2

2 B

Compressor of the exhaust gas turbocharger 2

3

Combustion chamber of the internal combustion engine 1

4

Exhaust pipe of the internal combustion engine 1

4a

Exhaust gas flow of the internal combustion engine 1

5

Fresh air duct of the internal combustion engine 1

6

Boost pressure sensor

7

throttle

8th

Intercooler

9

Air mass sensor

10

air valve

11

Bypass channel

12

catalyst

20

Bypass valve assembly

21

Wastegate of the bypass valve assembly 20

30

actuator

31

Engine, electric motor

32

pushrod

33

position sensor

34

force sensor

35

temperature sensor

40

control unit

41

driver circuit

42

positioner

43

diagnostic unit

44

summing element

45

Closing force regulator

46

Closing force estimating unit

60

Engine control unit

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008051818 A1 [0003, 0006]
• DE 102009028117 A1 [0007]

Claims (15)

Method for controlling an electric actuator ( 30 ) for a wastegate valve arrangement ( 20 ) of an exhaust gas turbocharger ( 2 ) an internal combustion engine ( 1 ), in which one in a bypass channel ( 11 ) of the exhaust gas turbocharger ( 2 ) disposed wastegate ( 21 ) by means of the actuator ( 30 ) for adjusting the via the bypass channel ( 11 ) on the exhaust gas turbocharger ( 2 ) bypassed exhaust gas stream ( 4a ) is closed or opened, wherein before the start of operation of the internal combustion engine ( 1 ) at least the closed position of the wastegate ( 21 ) is determined as a cold position value (Pos _cc ), after the start of operation at a load request of the internal combustion engine ( 1 ) the wastegate is acted upon by closing with a first closing force (F _w1 ) and thereby causing the closed position of the wastegate ( 21 ) is detected as a warm position value (Pos _wc ) and during the subsequent operation of the internal combustion engine ( 1 ) with closed wastegate ( 21 ) by means of the warm position value (pos _wc ) the position of the wastegate ( 21 ) is monitored. Method according to Claim 1, characterized in that a threshold value (Pos _s ) is determined as a function of the hot position value (Pos) and when this threshold value (Pos _s ) is exceeded by a position value (Pos _act ) of the wastegate ( 21 ) the closing force which brings about this position value (Pos _act ) is reduced. A method according to claim 1 or 2, characterized in that for determining the warm position value (pos _wc ) of the wastegate ( 21 ) used first closing force (F _w1 ) is lower than that for applying the wastegate ( 21 ) during operation of the internal combustion engine ( 1 ) generated second closing force (F _w2 , F _w22 ). Method according to one of the preceding claims, characterized in that for determining the warm position value (Pos _wc ) the wastegate ( 21 ) is applied using the cold position value (Pos _cc ) in such a way with a closing force damping the closing movement (F _act0 ) that the wastegate ( 21 ) performs a gentle closing movement in the closed position. Method according to claim 4, characterized in that the wastegate ( 21 ) is acted upon by the first closing force (F _w1 ) _{after being} acted upon by the damping closing force (F _act0 ). Method according to claim 5 , characterized in that during operation of the internal combustion engine ( 1 ) with each control of the wastegate ( 21 ) from an open position in its closed position the wastegate ( 21 ) is _{acted upon} first with the closing force damping closing force (F _act0 ), then with the first closing force (F _w1 ) and finally with the second closing force (F _w2 ). Method according to one of the preceding claims, characterized in that before the start of operation of the internal combustion engine ( 1 ) in addition to the closed position, the open position of Wastegate ( 21 ) is determined as the cold position value (Pos _co ) of the open position. Method according to one of the preceding claims, characterized in that after the start of operation of the internal combustion engine ( 1 ) the wastegate ( 21 ) is acted upon for opening with a third closing force and thereby causing the open position of the wastegate ( 21 ) as the warm position value (Pos _where ) of the open position is determined. Method according to one of the preceding claims, characterized in that the second closing force (F _w2 ) to a closing force setpoint value (F _req ) in dependence on a closing force actual value (F _act , F _{act_est} ) or to a desired value of the closing force determining operating parameter ( l _act ) of the actuator ( 30 ) as a function of an actual value (I _ist ) of this operating parameter (I _act ) is controlled. Method according to Claim 9, characterized in that when the threshold value (Pos _s ) is exceeded by a position value (Pos _act ) of the wastegate ( 21 ) the closing force setpoint or the setpoint of the operating parameter of the actuator ( 30 ) is reduced. A method according to claim 9 or 10, characterized in that the closing force actual value (F _act ) by means of a force sensor ( 34 ) is determined. Method according to claim 9 or 10 , characterized in that the closing force actual value (F _{act_est} ) from the operating _current (I _act ) and the operating temperature (T _act ) of the actuator ( 30 ) and preferably by means of a position sensor ( 33 ) certain position (Pos _act ) of the Wastegate ( 21 ) is estimated by means of a calculation model. Method according to one of Claims 9 to 12, characterized in that a control deviation is determined from the closing force setpoint value (F _req ) and the determined closing force actual value (F _act , F _{act_est} ) and a closing force _controller ( 50 ) for generating control signals (S _F , U _PWM ) for controlling the actuator ( 30 ) is supplied. Method according to Claim 9 or 10, characterized in that the operating current (I _act ) of the actuator (I _act ) of the actuator (10) determines the operating parameter determining the closing force (F). 30 ) is used, wherein a closing force setpoint (Freq) as a function of the position sensor ( 33 ) certain position (Pos _act ) of the Wastegate ( 21 ) and the operating temperature (T _act ) of the actuator ( 3 ) is determined by means of a computing model, an operating current setpoint (I _req ) and by comparison with an operating current actual value (I _ist ) a control deviation is determined which a closing force regulator ( 50 ) for generating control signals (S _F , U _PWM ) for controlling the actuator ( 30 ) is supplied. Device for carrying out the method according to one of the preceding claims, in particular for controlling an electric actuator ( 30 ) for a wastegate valve arrangement ( 20 ) of an exhaust gas turbocharger ( 2 ) an internal combustion engine ( 1 ) with one in a bypass channel ( 11 ) of the exhaust gas turbocharger ( 2 ) arranged wastegate ( 21 ), which by means of the actuator ( 30 ) for adjusting the via the bypass channel ( 11 ) on the exhaust gas turbocharger ( 2 ) bypassed exhaust gas stream ( 4a ) is closed or opened, wherein the device is formed before the start of operation of the internal combustion engine ( 1 ) at least the closed position of the wastegate ( 21 ) as a cold position value (Pos _cc ), after the start of operation at a load request of the internal combustion engine ( 1 ) the wastegate ( 21 ) to _act upon closing with a first closing force (F _w1 ) and thereby causing the closed position of the wastegate ( 21 ) as a warm position value (Pos _wc ) and during the subsequent operation of the internal combustion engine ( 1 ) with closed wastegate ( 21 ) by means of the warm position value (pos _wc ) the position of the wastegate ( 21 ).

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