DE102015205966A1 - Wastegateventilsystem, exhaust gas turbocharger, internal combustion engine and motor vehicle - Google Patents

Abstract

A wastegate valve system for an exhaust gas turbocharger comprises a housing (30) forming a valve seat, a valve body (28), and an actuator by which the valve body (28) can be pushed onto or off the valve seat as needed, the valve body (28) via a valve body first lever (44) on a first end portion of a valve shaft (48) and an actuator (56) of the actuator via a second lever (52) on a second end portion of the valve shaft (48) engages, wherein the valve shaft (48) in an area between the first end portion (46) and the second end portion (50) is rotatably mounted. Such a wastegate valve (26) according to the invention is characterized in that by the adjusting device (56) on the second lever (52) for pressing the valve body (28) on the valve seat force exerted on the one hand and by this pressing of the valve seat on the valve body (28) applied reaction force on the other hand at an angle less than 90 ° to each other.

Description

The invention relates to a wastegate valve system, an exhaust gas turbocharger with such a wastegate valve system, an internal combustion engine with such an exhaust gas turbocharger and a motor vehicle with such an internal combustion engine.

Exhaust gas turbochargers are used to increase the performance of internal combustion engines by fresh gas, the combustion chambers of an internal combustion engine of the internal combustion engine is supplied and is to be burned therein with fuel is compressed. As a result, the mass of the fresh gas which can be introduced into the individual combustion chambers for a combustion process and thereby also the amount of fuel to be reacted with this fresh gas during the combustion can be increased. For the compression of the fresh gas is a compressor which is driven in rotation by a turbine of the exhaust gas turbocharger. For this purpose, the turbine itself is flowed through by the exhaust gas which arises during the combustion of the fuel fresh-gas mixture in the combustion chambers and is driven in rotation.

For boost pressure control and to avoid overloading exhaust gas turbochargers during operation of the internal combustion engine under full load and at high speeds, are integrated into these so-called waste gates. These are controllable bypasses by means of which the respective turbine wheels can be bypassed for the exhaust gas flows. By means of controlled openable wastegate valves, the size of the exhaust gas flows conducted via the bypasses can be regulated in order to limit the amount of admission of the turbine wheels to the exhaust gas streams.

Because of the sometimes very high exhaust gas temperatures, the actuators, by means of which wastegate valves are actuated, outside of the exhaust gas flowed through the interiors of the exhaust gas turbocharger and also usually located in the region of the compressor. An actuation of the wastegate valves then takes place by means of transmission means, which generally comprise a rotatably mounted in a housing opening shaft and two, at opposite ends of the shaft rotatably mounted on this lever, said one lever, spaced from the shaft, carries the valve body of the wastegate valve while the other lever, also spaced from the shaft, is connected to an actuating rod of an actuator. A movement of the actuating rod of the actuator is thus translated into a rotational movement of the shaft, which in turn leads to a movement of the valve body in a part-circular path.

Since exhaust gas turbochargers are operated within a fairly wide temperature range and usually the shaft on the one hand and a bearing shell for the shaft forming housing of the exhaust gas turbocharger on the other hand mostly made of different materials, the bearing of the shaft is dimensioned within this bearing shell regularly with a relatively large game to ensure rotation within the entire temperature range. This leads in known exhaust gas turbochargers to a skewing of the shaft within the bearing shell formed by the housing or integrated into the housing, whereby the shaft and the bearing shell at two points selectively (or taking into account the elasticity of the components: linear contact), which opposite a linear (or areal) contacting with a locally significantly increased wear goes along.

To overcome this problem is in the DE 10 2009 048 125 A1 provided that the valve body of a wastegate valve is fixed between two bearing points on the valve shaft, that the force exerted by the actuator on the valve shaft forces on the one hand and the force exerted by the valve body due to the exhaust gas pressure on the valve shaft forces on the other hand in the bearing points are aligned opposite, whereby the friction in the bearings should be reduced. It is provided to press the valve body by the exercise of a tensile force by means of the adjusting device on the associated valve seat. The forces which are exerted on the one hand by the adjusting device on the corresponding lever and on the other hand by the valve seat as a reaction force on the valve body, are aligned approximately opposite.

The from the DE 10 2009 048 125 A1 known storage for the shaft of a wastegate valve is relatively complex and therefore expensive and sometimes only with difficulty or using a relatively large space in the housing of an exhaust gas turbocharger integrated.

In the DE 10 2011 051 560 A1 a wastegate valve system is shown in which the forces, on the one hand from an adjusting device for pressing a valve body on a valve seat to a first end of a on the other hand, as reaction force due to this pressing from a valve seat to the valve body and exerted therefrom on a first end of a second lever are aligned at an angle of 90 °. The respective second ends of the levers are interconnected in the region of a pivot bearing.

And finally is out of the DE 10 2011 105 997 A1 a wastegate valve system known in which the forces exerted on the one hand by a setting device for pressing a valve body on a valve seat on a first end of a first lever and on the other hand as a reaction force due to this pressing from a valve seat on the valve body and from there to a first End of a second lever are exercised, approximately the same, ie pointing in the same direction and parallel to each other, are aligned. The respective second ends of the levers are connected to each other via a pivot pin.

Based on this prior art, the present invention seeks to provide a low-wear and at the same time easily trained storage for the shaft of a wastegate valve system.

This object is achieved by means of a wastegate valve system according to the patent claim 1. An exhaust gas turbocharger having such a wastegate valve system is the subject matter of patent claim 6 and an internal combustion engine comprising such an exhaust gas turbocharger is the subject of claim 7. Advantageous embodiments of the wastegate valve system according to the invention and thus of the exhaust gas turbocharger according to the invention and the internal combustion engine according to the invention are objects of the further claims and will become apparent from the following description the invention.

The invention is based on the finding that the increased wear caused skew the valve shaft in a arranged between the two levers bearing shell is due to the fact that the forces on the one hand from the operating rod to the associated lever and from this into the corresponding end of the shaft are introduced to press the valve body on the associated valve seat, and on the other hand arise as reaction forces from this pressing of the valve body and act on the other end of the valve shaft, are generally aligned opposite, whereby the shaft with a torque about a radial axis (perpendicular to the longitudinal axis axis) is loaded, which leads to the skewing of the shaft within the bearing shell. In addition to these reaction forces in the regularly encountered embodiment of waste gates with arranged on the outlet side of the bypass and in the flow direction of the exhaust gas flow Wastegateventil still resulting from the pressure of the exhaust gas on the valve body forces.

A basic idea of the invention resulting from this recognition is that skewing of the shaft within the bearing shell and thus locally increased wear can be avoided or at least substantially reduced if these forces are no longer opposing but are as far as possible directed, ie. pointing in the same direction and aligned in parallel are.

In particular, the space available for the integration of the wastegate valve system in an exhaust gas turbocharger may under certain circumstances prevent such an alignment of these forces, which is as rectilinear as possible. However, the advantage according to the invention always arises when the forces considered here, which are introduced into the shaft at two spaced apart locations, are not aligned exactly opposite one another. Particularly pronounced is the advantage of the invention, if these forces have at least equal components and thus - with the same basic orientation - an angle smaller than 90 ° is formed between their reference lines. The smaller this angle, the lower the torque exerted by the forces on the valve shaft, so that increasingly a linear or (taking into account elasticities of the components involved) over a large area and over a maximum, ideally the entire length of storage extending contacting the valve shaft with the bearing shell instead of the known from generic wastegate valve systems double punctual or double small area contacting.

Following this basic idea is a generic wastegate valve system for an exhaust gas turbocharger, which has at least one valve seat forming a housing, a valve body and an actuating device by which the valve body can be pressed or lifted onto the valve seat as required, wherein the valve body via a first lever a first end portion of a valve shaft and an actuating device of the actuating device via a second lever at a second end portion of the valve shaft engages, wherein the valve shaft (preferably exclusively) in a region between the first end portion and the second end portion is rotatably mounted, according to the invention characterized in that the force exerted by the adjusting device on the second lever for pressing the valve body against the valve seat, on the one hand, and the reaction force exerted on the valve body by this pressing of the valve seat on the other its at an angle less than 180 °, preferably less than 90 ° and further advantageously less than 45 ° are aligned. The most advantageous storage of the valve shaft results when these forces are as nearly as possible, i. pointing in the same direction and aligned in parallel, are.

According to the invention, the term "angle" is understood to be the smallest angle included in the lines of action of the forces. Unless these lines of action intersect, this applies to the Projection of the lines of influence into the corresponding level.

Such a wastegate valve system according to the invention can be implemented in a constructively advantageous manner if it is provided that a pressure force is to be exerted on the second lever by the adjusting device for pressing the valve body onto the valve seat. This may, in particular with regard to the space to be provided for the wastegate valve system advantageous in comparison to a configuration in which for pressing the valve body on the valve seat to exert a tensile force by the actuator to the second lever, effect.

A structurally simple and thus cost-effective storage for the valve shaft can be achieved in that it is rotatably mounted between the first end portion and the second end portion in a bearing opening of the housing. It can also be provided that the bearing opening of the housing is formed by a bearing sleeve, which may be formed with respect to a base housing made of a different material that may be selected in particular with regard to the storage function. In this case, the bearing sleeve can be detachably or non-detachably integrated into the basic housing.

An exhaust gas turbocharger according to the invention comprises at least one turbine, a compressor drivable by the turbine and further provided for bypassing a turbine runner of the turbine bypass, wherein the bypass is controllable by means of a wastegate valve system according to the invention with respect to the leading to the bypass subset of the available exhaust gas flow. The housing of the wastegate valve system according to the invention can preferably be integrated in a housing of the exhaust gas turbocharger.

Such an exhaust gas turbocharger also characterizes an internal combustion engine according to the invention. This further comprises at least one internal combustion engine, which forms one or more combustion chambers, as well as a fresh gas train via which fresh gas can be supplied to the combustion chamber (s) and an exhaust system via which exhaust gas can be discharged from the combustion chamber (s), the compressor of the exhaust gas turbocharger being introduced into the combustion chamber Fresh gas train and the turbine of the exhaust gas turbocharger are integrated into the exhaust system.

The invention also relates to a motor vehicle, in particular a wheel-based motor vehicle (preferably a car or truck), with an internal combustion engine according to the invention. In this case, the internal combustion engine can be provided in particular for (direct or indirect) provision of the traction drive power for the motor vehicle.

The indefinite articles ("a", "an", "an" and "an"), in particular in the patent claims and in the description generally describing the claims, are to be understood as such and not as numerical words. Corresponding to this concretized components are thus to be understood that they are present at least once and may be present more than once.

The present invention will be explained in more detail with reference to embodiments shown in the drawings. In the drawings shows:

1 schematically an internal combustion engine according to the invention;

2 : An exhaust gas turbocharger according to the invention, as used, for example, in an internal combustion engine according to the 1 can be used;

3 a section of a horizontal section through the exhaust gas turbocharger according to the 2 ;

4 schematically shows the resulting from the inventive design of a wastegate valve system advantages for the storage of the valve shaft;

5 in comparison, the corresponding mounting of a valve shaft of a generic wastegate valve system; and

6 : a motor vehicle according to the invention.

The in the 1 schematically illustrated internal combustion engine comprises an internal combustion engine 10 , This is designed for example as four-cylinder, operated according to the diesel or petrol principle reciprocating internal combustion engine. The internal combustion engine 10 Fresh gas is supplied via a fresh gas train into combustion chambers, which are discharged from the cylinders 12 in connection with the piston guided therein and down and a cylinder head (not shown) are limited, is used for the combustion of directly injected fuel. The resulting during combustion exhaust gas is removed via an exhaust line.

In the exhaust system is a turbine 14 an exhaust gas turbocharger integrated. A turbine runner (not shown) of the turbine 14 is driven in rotation by the exhaust gas flow, this rotation being via a shaft 16 to a compressor impeller (not shown) of a compressor integrated into the fresh gas train 18 the exhaust gas turbocharger is transmitted. The Rotation of the compressor wheel causes a compression of the fresh gas and thus an increase in the mass of convertible into the combustion chambers fresh gas. This improves the filling of the combustion chambers and thus the achievable performance of the internal combustion engine 10 ,

In order to prevent part of the filling improvement realized by the compression from being compensated by the temperature increase of the fresh gas which accompanies the compression, there is a charge-air cooler 20 provided, which cools the compressed fresh gas.

The exhaust gas turbocharger also has a wastegate 22 on. This includes a bypass bypassing the turbine impeller 24 and an inventive wastegate valve system 26 with a valve body 28 , by means of which the downstream outlet opening of the bypass 24 more or less closable (cf. 3 ), as well as an actuator which provides a controlled movement of the valve body 28 allows.

Such an inventive wastegate valve system 26 is more detailed in the 2 and 3 in the composite of an exhaust gas turbocharger according to the invention, as in an internal combustion engine according to the 1 can be used shown.

The in the 2 and 3 exhaust gas turbocharger shown comprises a multi-part housing 30 within which a compressor impeller (not visible), a turbine impeller (not visible) and a shaft connecting the compressor impeller rotatably connected to the turbine wheel (not visible) are rotatably mounted. An inlet flange 32 a turbine housing part 34 of the housing 30 forms an inlet and an outlet flange 36 an outlet for an exhaust gas flow, which in the flow through the turbine housing part 34 flows through the turbine wheel and thereby drives this rotating. This rotation is transmitted by means of the shaft to the compressor impeller, which leads to a compression of a fresh gas flow, which is a compressor housing part 38 starting from one of an inlet port 40 of the compressor housing part 38 trained inlet to one of an outlet 42 of the compressor housing part 38 trained outlet flows through.

An in the turbine housing part 34 integrated bypass 24 bypassing the turbine impeller connects the inlet to the outlet of the turbine. The outlet opening of the bypass 24 is by means of a flap-shaped valve body 28 lockable (cf. 3 ). The valve body 28 is over a first lever 44 with a first end portion 46 a valve shaft 48 connected, with the first lever 44 and the valve shaft 48 are integrally formed. At a second end portion 50 the valve shaft 48 is a second lever 52 rotatably connected. This second lever 52 serves the articulation of an actuating rod 54 an adjusting device 56 through which the valve body 28 either to close the bypass 24 on one the outlet opening of the bypass 24 surrounding valve seat 66 pressed or more or less from this valve seat 66 can be lifted to flow defined subsets of the exhaust gas flow, bypassing the turbine impeller from the inlet to the outlet of the turbine.

In the area between the two end sections 46 . 50 is the valve shaft 48 within a bearing opening of the turbine housing part 34 rotatably mounted. This bearing opening is of a tubular bearing sleeve 58 formed, in turn, in a receiving opening of a base housing of the turbine housing part 34 is stored (see. 3 ). The bearing sleeve 58 serves as a bearing shell within which the valve shaft 48 is rotatably mounted.

By the exercise of tensile or compressive forces by means of the adjusting device 56 and the operating rod 54 to the appropriate pivot point of the second lever 52 becomes a movement of the operating rod 54 in a rotational movement of the valve shaft 48 translated, in turn, to a movement of the valve body 28 on a part-circular path, whereby the valve body 28 either in the direction of the valve seat 66 or can be moved away from it.

For pressing the valve body 28 on the valve seat 66 is the exercise of a compressive force 60 (see. 2 ) on the second lever 52 by means of the adjusting device 56 and the operating rod 54 required. The force with which the valve body 28 on the valve seat 66 is pressed causes an oppositely directed reaction force from the valve seat 66 on the valve body 28 acts. As a result of the configuration of the wastegate valve system with opening in the flow direction of the exhaust gas flow valve body 28 adds up on the valve seat 66 resting valve body 28 to this reaction force nor a compressive force whose height is the pressure of the exhaust gas in the region of the inlet and the outlet opening covering the surface of the valve body 28 results. The corresponding total force 62 is also in the 2 shown. At partially or completely from the valve seat 66 lifted valve body 28 the force on the valve body 28 from the pressure and flow rate of the exhaust gas in combination with the applied area of the valve body 28 , In the 2 It can also be seen that by the adjusting device 56 on the second lever 52 exerted pressure force 60 on the one hand and the total force acting on the valve body 62 on the other hand point the same basic direction and the smallest angle α between the projections of the lines of action of these forces 60 . 62 in the corresponding plane (here approximately the leaf level) is relatively small (in about 20 °). This results in the in the 4 simplified advantages with regard to the storage of the valve shaft 48 in the bearing sleeve 58 , It is between the outside of the valve shaft 48 and the inside of the bearing sleeve 58 shown a relatively large game, as must be provided in many cases for the storage of wastegate valve systems to over the large temperature range within which exhaust gas turbochargers are operated, a rotation of the valve shaft 48 in the bearing sleeve 58 to reach.

The 4 shows that by substantially rectified forces 60 . 62 (from the actuator 56 exerted pressure on the one hand and on the valve body 28 acting total force on the other hand) a line-shaped (in the longitudinal direction of the valve shaft 48 running) or large-area contact of the valve shaft 48 with a partial section of the bearing sleeve 58 can be realized while in conventional exhaust gas turbochargers, in which the forces are aligned approximately opposite, a skewing of the valve shaft 48 inside the bearing bush 58 and thereby sets a double point or double small area contact (see. 5 ), which is accompanied by a locally significantly increased wear.

The 6 shows still another inventive motor vehicle with an internal combustion engine 64 , which is provided for providing the traction drive power, for this purpose indirectly (with the interposition of a transmission) of the internal combustion engine 10 generated mechanical power is transmitted to driven wheels of the motor vehicle. Alternatively (not shown), the mechanical power of the internal combustion engine 10 are also used to drive a generator, whereby electrical energy is generated, which is used directly or indirectly (with the interposition of a battery) for driving an electric motor, wherein the electric motor in turn can drive the driven wheels of the motor vehicle. The internal combustion engine 64 of the motor vehicle, for example, according to the 1 be educated.

LIST OF REFERENCE NUMBERS

10

internal combustion engine

12

cylinder

14

turbine

16

wave

18

compressor

20

Intercooler

22

wastegate

24

bypass

26

Wastegate valve system

28

valve body

30

casing

32

Inlet of the turbine housing part

34

Turbine casing

36

Outlet nozzle of the turbine housing part

38

Compressor housing part

40

Inlet socket of the compressor housing part

42

Outlet nozzle of the compressor housing part

44

first lever

46

first end portion of the valve shaft

48

valve shaft

50

second end portion of the valve shaft

52

second lever

54

actuating rod

56

locking device

58

bearing sleeve

60

thrust

62

total power

64

Internal combustion engine

66

valve seat

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 102009048125 A1 [0006, 0007]
• DE 102011051560 A1 [0008]
• DE 102011105997 A1 [0009]

Claims (8)

Wastegate valve system ( 26 ) for an exhaust gas turbocharger with a valve seat ( 66 ) forming housing ( 30 ), a valve body ( 28 ) and an actuating device, through which the valve body ( 28 ) as needed on the valve seat ( 66 ) can be pressed or lifted from this, wherein the valve body ( 28 ) via a first lever ( 44 ) at a first end portion ( 46 ) a valve shaft ( 48 ) and an adjusting device ( 56 ) of the actuator via a second lever ( 52 ) at a second end portion ( 50 ) of the valve shaft ( 48 ), wherein the valve shaft ( 48 ) in a region between the first end portion ( 46 ) and the second end portion ( 50 ) is rotatably mounted, characterized in that the of the adjusting device ( 56 ) on the second lever ( 52 ) for pressing the valve body ( 28 ) force exerted on the valve seat on the one hand and by this pressing of the valve seat ( 66 ) on the valve body ( 28 ) applied reaction force on the other hand are aligned at an angle less than 90 ° to each other. Wastegate valve system ( 26 ) according to claim 1, characterized in that the forces are aligned at an angle less than 45 ° to each other. Wastegate valve system ( 26 ) according to claim 1 or 2, characterized in that the forces are rectified. Wastegate valve system ( 26 ) according to one of the preceding claims, characterized in that of the adjusting device ( 56 ) for pressing the valve body ( 28 ) on the valve seat ( 66 ) a pressure force on the second lever ( 52 ) is exercised. Wastegate valve system ( 26 ) according to one of the preceding claims, characterized in that the valve shaft ( 48 ) between the first end portion ( 46 ) and the second end portion ( 50 ) in a bearing opening of the housing ( 30 ) is rotatably mounted Exhaust gas turbocharger with a by-pass intended for bypassing a turbine runner ( 24 ) and a wastegate valve system ( 26 ) according to one of the preceding claims for quantity control of a bypass ( 24 ) guided exhaust stream. Internal combustion engine ( 64 ) with an exhaust gas turbocharger according to claim 6. Motor vehicle with an internal combustion engine ( 64 ) according to claim 7.

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