DE102007009267B4 - turbocharger - Google Patents

Abstract

Turbocharger (1)
with a compressor (2),
with a turbine (4) connected to the compressor (2) via a shaft (3),
• having an exhaust gas inlet (5) and an exhaust gas outlet (7)
- With a bypass line (6),
Bypassing the turbine (4) from the exhaust gas inlet (5) and leading to the exhaust gas outlet (7),
and
• In which a shut-off device (8) is arranged, which is actuated by an actuator (9), wherein
- The actuator is designed as an electromagnetic actuator (9; 22),
characterized,
the actuator (9; 22) comprises a steel housing cylinder (18; 25) and an aluminum cylinder (19; 26) disposed within the steel housing cylinder (18; 25).

Description

The invention relates to a turbocharger according to the preamble of claim 1.

Such a turbocharger is from the DE 197 11 307 A1 known. The turbocharger there has a flow control actuator responsive to the air pressure in the intake air outlet for actuating the flow control member disposed in the exhaust gas bypass passage. The JP S54-1337 513 A relates to a turbocharger with a bypass channel and a bypass valve. The bypass valve of the turbocharger is described either as an electromagnetic valve or designed as a diaphragm-controlled valve.

It is accordingly an object of the present invention to provide a turbocharger of a specified according to the preamble of claim 1, whose actuator is suitable for applications in which the arranged in the bypass line obturator or wastegate in operation against a certain pressure opened or closed must become. It is another object of the invention to provide a turbocharger with a more reliable electromagnetic actuator for a bypass obturator.

The solution of this object is achieved by the features of claim 1.

By including the actuator with a steel shell cylinder, electromagnetic compatibility (i.e., shielding) with the environment can be ensured. This is possible because the steel jacket or steel housing cylinder is impermeable to magnetic field lines. By the aluminum cylinder, which is arranged within the steel housing cylinder, on the one hand, a minimum distance between internal components of the actuator and the steel housing cylinder can be ensured. As a result, a field weakening in the interior of the actuator can be prevented. On the other hand, can be provided by the aluminum cylinder good heat conduction to the outside.

The fact that the actuator is designed as an electromagnetic actuator, it is possible to interpret it in a first case so that it opens the wastegate against a certain pressure gradient, that is, in the case of an actuator failure, the wastegate is not due to the pressure gradient opens by itself. It is possible to perform a design with specification of the required control current given the desired stroke, the desired lifting force, the desired closing force, the desired rest position and the maximum permissible outer dimensions of the actuator, this interpretation is done in dependence of the coil winding number.

In the other above-mentioned second case, the actuator type according to the invention is suitable for applications in which the wastegate must be closed in operation against a certain pressure gradient, d. H. in which, in the case of an actuator failure, this opens on its own due to the pressure gradient.

In this alternative, the design according to the invention, when specifying the desired stroke, the desired maximum closing force and the maximum permissible external dimensions of the actuator, permits a design with specification of the required control current, the coil winding number having to be considered.

The dependent claims have advantageous developments of the invention to the content.

Further details, advantages and features of the invention will become apparent from the following description of exemplary embodiments and the drawing.

• 1 eine schematisch stark vereinfachte Darstellung des erfindungsgemäßen Turboladers,
• 2 eine schematisch stark vereinfachte Darstellung einer ersten Ausführungsform eines Aktuators, der in Zusammenhang mit dem in 1 dargestellten Turbolader verwendet werden kann,
• 3 bis 5 Diagramme zur Erläuterung der Wirkungsweise des Aktuators gemäß 2,
• 6 eine der 2 entsprechende Darstellung einer zweiten Ausführungsform des erfindungsgemäßen Aktuators, der mit dem Turbolader gemäß 1 verwendet werden kann, und
• 7 bis 11 Diagramme zur Erläuterung der Wirkungsweise des Aktuators gemäß 6.

It shows:

• 1 a schematically greatly simplified representation of the turbocharger according to the invention,
• 2 a schematically simplified view of a first embodiment of an actuator, in connection with the in 1 illustrated turbocharger can be used
• 3 to 5 Diagrams for explaining the operation of the actuator according to 2 .
• 6 one of the 2 corresponding representation of a second embodiment of the actuator according to the invention, with the turbocharger according to 1 can be used, and
• 7 to 11 Diagrams for explaining the operation of the actuator according to 6 ,

In 1 is a schematically simplified view of a turbocharger according to the invention 1 shown.

The turbocharger 1 has a compressor 2 on whose compressor wheel via a shaft 3 with a turbine wheel of a turbine 4 communicates.

The turbine 4 has an exhaust inlet 5 on that with an exhaust pipe 13 an internal combustion engine is in communication.

Furthermore, the turbine points 4 an exhaust outlet 7 on.

1 further illustrates a bypass line 6 , which precede the turbine inlet from the exhaust inlet 5 branches off and directly to the exhaust outlet 7 leads, so through this bypass line 6 the turbine 4 is bypassed.

In the bypass line 6 is a shut-off device 8th arranged, which may be formed for example as a so-called "wastegate". The obturator 8th is actuated by an actuator that passes through the block 9 . 22 can be operated according to the following to be described alternative embodiments.

The actuator 9 . 22 is inventively designed as an electromagnetic actuator whose structure is described below with reference to 2 and 6 will be explained in more detail.

1 further clarifies an air inlet to complete 10 in the compressor 2 and an air outlet 11 from the compressor 2 , to the internal combustion engine 12 through the compressor 2 directs compressed air.

The turbocharger 1 according to 1 Of course, all other common parts, but for simplicity in 1 are not shown, since they are not important for the explanation of the invention.

The in 2 illustrated actuator 9 is described below. This actuator 9 has a main coil 14 , a startup coil 15 , one between the main coil 14 , and the start coil 15 arranged annular permanent magnet 16 on. Further, a massive steel cylinder 17 provided, which is arranged in the direction of the longitudinal axis L and movable along the latter and of the main coil 14 , the start coil 15 and the annular permanent magnet 16 is surrounded. A graduated aluminum cylinder 19 surrounds the main coil 14 the starting coil 15 and the permanent magnet 16 , A non-metallic guide sleeve 21 surrounds the steel cylinder 17 and a control rod 20 on the steel cylinder 17 is attached, and in the middle of a steel housing cylinder 18 out leads.

The design can simply be symmetrical or axisymmetric. At the in 2 illustrated first embodiment of the actuator is described an axis L for axis-symmetrical design characterized therein.

The following is the function of the first actuator type 9 described.

When de-energized, the permanent magnet forces 16 the steel cylinder 17 in a neutral position. Depending on whether the startup coil 15 or the main coil 14 The current flows through the steel cylinder 17 deflected up or down. The fact that the force for opening the obturator or wastegate is greater than that required for closing, causes the different coil sizes.

Depending on the current, the number of turns, the position, the dimension and the way the coil is operated 14 can be wound on the steel cylinder 17 acting maximum force of the respective maximum pressure difference corresponding force to the wastegate flap, to be adjusted.

The starting coil 15 is used immediately after and after the start of the internal combustion engine and closes the wastegate. The main coil 14 is now power-free.

Once an exhaust gas turbocharger speed level is reached, from which must be blown off, comes the main coil 14 for use.

By varying the current in the main coil 14 or in the starting coil 15 the wastegate is opened more or less wide.

The with the steel cylinder 17 connected control rod ( 20 ) transmits this movement or force to the lever of the wastegate flap (s. 1 ).

The non-metallic guide sleeve 21 serves as a guide for the steel cylinder 17 in the coil, or in the permanent magnet.

The impermeable for magnetic field lines steel jacket or steel housing cylinder 18 ensures electromagnetic compatibility (ie shielding) with the environment.

The connection between this steel housing cylinder 18 and the internal components is through the aluminum sheath or stepped aluminum cylinder 19 produced.

In the event of a power interruption comes the permanent magnet 16 used and holds the wastegate in an open position. Overspeeding the charger is thus prevented.

Hereinafter, for this embodiment, the operation of the wastegate will be exemplified with reference to FIG 3 described.

The operation of the wastegate via a lever, with a Hebelarmverhältnis of z. 2: 1.

The opening of the wastegate is in the de-energized rest position with z. B. 2 mm prescribed. Due to the lever arm ratio this results in a rest position of 4 mm on the control rod 20 , This condition corresponds, for example, to the situation in which the engine is stationary.

When the engine is started, the wastegate must be closed. The starting coil 15 is activated and moves the control rod 20 by 4 mm in the direction of the start coil 15 , The maximum power available at the control rod 20 is between 25 N (0 mm) and 26 N (4 mm). Taking into account the lever arm ratio, this corresponds to 50 N - 52 N at the wastegate.

If the engine is accelerated and its speed level exceeds the value from which it must be blown off, the wastegate is opened again. The main coil 14 is activated and moves the control rod 20 in the direction of the main coil 14 , The maximum power available at the control rod 20 is z. For example, with the wastegate closed, 67 N. Taking into account the lever arm ratio, this corresponds to 134 N at the wastegate.

This value could theoretically open a wastegate with a bore diameter of 29 mm against a pressure drop of 2 bar.

The maximum way of the control rod 20 is in the present case z. B. 14 mm, ie, the wastegate can be opened up to 7 mm wide.

Of course, the maximum force of the actuator can be 9 in one or the other direction by varying the dimensions of the individual components such as coil, cylinder, and permanent magnet influence.

3 shows the force on the steel cylinder 17 with a diameter of z. B. 48 mm depending on the axial position of the steel cylinder 17 ,

Special features of the design:

It should be noted that the magnetic flux density does not exceed the magnetic saturation value applicable to the cylinder material. For steel, this value is about 1.9 Tesla.

4 illustrates how this value comes about. The diagram shows that the magnetic flux density [B] as a function of the magnetic field strength [H] for steel has a non-linear characteristic, which means that from a certain value (about 1.9 Tesla) an increase in field strength is no longer in results in a significant increase in Kraftflussdichte.

5 shows the result of a numerical simulation of the magnetic flux density, which is necessary for the opening of a closed wastegate flap force at the control station 20 equivalent.

The representation is axially symmetric according to the calculation approach.

It provides insight into how far the magnetic flux density is away from the magnetic saturation value for the cylinder material, and how well the shielding of the magnetic field outwardly through the steel shell cylinder 18 succeed.

Finally, with respect to the enclosure, note that there is a minimum radial distance between the steel shell cylinder 18 and to ensure the internal components is to weaken the field inside the actuator 9 submissions. This minimum distance is through the aluminum jacket or aluminum cylinder 19 guaranteed, which has no ferromagnetic property, but ensures the heat conduction to the outside.

In the axial direction, such a minimum distance is not necessary.

The in 6 illustrated second actuator type 22 is described below according to a second embodiment of the invention. This actuator 22 has a coil 23 , a massive steel cylinder 24 which is arranged in the direction of the longitudinal axis L and movable along this and an aluminum cylinder 26 that's the coil 23 surrounds. The steel cylinder 24 is from a non-metallic guide sleeve 28 surround. A control rod 27 is on the steel cylinder 24 attached and centered from the steel housing cylinder 25 led out.

The following is the function of the actuator type 22 described.

Depending on whether the coil 23 is supplied with electricity, arises in the steel cylinder 24 one on the control rod 27 related tensile force. The direction of this tensile force corresponds to the closing direction of the wastegate.

Depending on the current, the number of turns, the position, the dimension and the way the coil is operated 23 can be wound on the cylinder 24 acting maximum force of the respective maximum pressure difference corresponding tensile force can be adapted to the wastegate flap.

The with the cylinder 24 connected control rod 27 transfers this tensile force to the lever of the wastegate flap.

When starting the coil 23 supplied with power and the wastegate closed.

Once an exhaust gas turbocharger speed level is reached, from which it is necessary to blow off, the current is reduced until the wastegate opens.

By varying the current in the coil 23 the wastegate is opened more or less wide.

The non-metallic guide sleeve 28 serves as a guide for the cylinder 24 in the coil 23 ,

The impermeable for magnetic field lines steel jacket or steel housing cylinder 25 ensures electromagnetic compatibility (ie shielding) with the environment.

The connection between this steel shell and the inner components is through the aluminum shell or aluminum cylinder 26 produced.

In the event of a power interruption, the steel cylinder is force-free and allows the pressure difference between turbine and exhaust tract to open the wastegate. Overspeeding the charger is thus prevented.

Hereinafter, for the second embodiment, the operation of the wastegate will be described by way of example with reference to FIG 6 described.

The operation of the wastegate via a lever, with a Hebelarmverhältnis of z. 2: 1.

The actuator 22 must be positioned so that the highest possible tensile force coincides with the position in which the wastegate is closed, in 6 this corresponds to 10 mm in the pulling direction.

When the engine is started, the wastegate must be closed. The sink 23 is activated. The required closing force is still low.

If the engine is accelerated and its speed level exceeds the value from which it must be blown off, the wastegate is opened again. The current in the coil 23 is reduced accordingly.

The greatest closing force is required when the blow-off process is ended. The maximum power available at the control rod 27 in the present case is about 83 N. Taking into account the lever arm ratio, this corresponds to 166 N at the wastegate.

With this value, theoretically, a wastegate with a bore diameter of 32.5 mm could be closed against a pressure drop of 2 bar.

The maximum way of the control rod 27 in the present case is 12.5 mm, ie the wastegate can be opened up to 6.25 mm due to the lever ratio.

The outer dimensions of the actuator 22 amount in the present case z. B. 114 mm in diameter at a height of 100 mm.

7 shows the force on the cylinder 24 with a diameter of 40 mm depending on the axial position of the cylinder 24 for a coil with 3000 Amperewindungen.

This shows the favorable characteristic of the actuator 22 , The closer one gets to the closure position of the wastegate (-10 mm), the greater the required closing force, but at the same time the maximum possible pulling force available. Of course, the maximum tensile force of the actuator can be 22 by varying the dimensions of the individual components such as coil 23 and cylinders 24 influence. Thus, the smallest possible actuator size for the respective application can be determined.

8th shows how the highest possible pulling force of the actuator 22 depending on the diameter of the cylinder 24 for a coil with 3000 Ampere turns changes.

shows, for example, how the highest possible tensile force of the actuator 22 depending on the current through the coil 23 as well as depending on the number of turns z. B. for a cylinder diameter of 40 mm changes.

Special features of the design:

It should be noted that the magnetic flux density does not exceed the magnetic saturation value applicable to the cylinder material. For steel, this value is about 1.9 Tesla.

10 illustrates how this value comes about. The diagram shows that the magnetic flux density [B] as a function of the magnetic field strength [H] for steel has a non-linear characteristic, which means that from a certain value (about 1.9 Tesla) an increase in field strength is no longer in results in a significant increase in Kraftflussdichte.

11 shows the result of a numerical simulation of the magnetic flux density, the closing of a wastegate valve z. B. with a force of 83 N at the control station 20 equivalent.

The representation is axially symmetric according to the calculation approach.

It provides insight into how far the magnetic flux density is away from the magnetic saturation value for the cylinder material, and how well the shielding of the magnetic field outwardly through the steel shell cylinder 25 succeed.

Finally, with respect to the enclosure, note that there is a minimum radial distance between the steel shell cylinder 25 and to ensure the internal components is to weaken the field inside the actuator 22 submissions. This minimum distance is through the aluminum jacket or aluminum cylinder 26 guaranteed, which has no ferromagnetic property, but ensures the heat conduction to the outside.

In the axial direction, such a minimum distance is not necessary.

LIST OF REFERENCE NUMBERS

1

Turbocharger / turbocharger

2

compressor

3

wave

4

turbine

5

exhaust inlet

6

bypass

7

Abgassauslass

8th

shutoff

9

actuator

10

Air intake in 2

11

Air outlet from 2

12

Motor / engine

13

exhaust pipe

14

main coil

15

starting coil

16

annular permanent magnet

17

massive steel cylinder

18

Steel housing cylinder with longitudinal axis L

19

stepped aluminum cylinder

20

control rod

21

non-metallic guide sleeve

22

actuator

23

Kitchen sink

24

massive steel cylinder

25

Steel housing cylinder

26

aluminum cylinder

27

control rod

28

non-metallic guide sleeve

Claims (5)

Turbocharger (1) - with a compressor (2), - with a with the compressor (2) via a shaft (3) connected turbine (4), • having an exhaust gas inlet (5) and an exhaust gas outlet (7) - with a Bypass line (6), • which bypasses the turbine (4) branches off from the exhaust gas inlet (5) and leads to the exhaust gas outlet (7), and • in which a shut-off device (8) is arranged, which is actuated by an actuator (9), wherein the actuator is formed as an electromagnetic actuator (9; 22), characterized in that the actuator (9; 22) comprises a steel housing cylinder (18; 25) and an aluminum cylinder (19; 26) disposed within the steel housing cylinder (18; 25) is arranged. Turbocharger (1) according to Claim 1 characterized in that the actuator (9) comprises: - a main coil (14), - a starting coil (15) - an annular permanent magnet (16) disposed between the main coil (14) and the starting coil (15), - A solid steel cylinder (17) which is arranged centrally in the steel housing cylinder (18) within the main coil (14), the starting coil (15) and the permanent magnet (16), - wherein the aluminum cylinder (19) is stepped and outside the main coil (14) surrounding the start coil (15) and the permanent magnet (16), and - a control rod (20) fixed to the steel cylinder (17) and led out centrally from the steel shell cylinder (18). Turbocharger according to Claim 2 , characterized in that the steel cylinder (17) is surrounded by a non-metallic guide sleeve (21). Turbocharger according to Claim 1 characterized in that the actuator (22) comprises: - a spool (23), - a solid steel cylinder (24) located centrally in the steel housing cylinder (25) inside the spool (23), - the aluminum cylinder (23) 26) surrounds the coil (23) on the outside, and - a control rod (27) which is connected to the solid steel cylinder (24) and is led out centrally from the steel cylinder housing (25). Turbocharger (1) according to Claim 4 , characterized in that the solid steel cylinder (24) is surrounded by a non-metallic guide sleeve (28).

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