WO2016156310A1

WO2016156310A1 - Wastegate valve system, exhaust-gas turbocharger, internal combustion engine, and motor vehicle

Info

Publication number: WO2016156310A1
Application number: PCT/EP2016/056790
Authority: WO
Inventors: Matthias TOMECKI
Original assignee: Volkswagen Aktiengesellschaft
Priority date: 2015-04-01
Filing date: 2016-03-29
Publication date: 2016-10-06
Also published as: DE102015205966A1

Abstract

The invention relates to a wastegate valve system for an exhaust-gas turbocharger comprising a housing (30), which forms a valve seat, a valve body (28), and an actuating device, by means of which the valve body (28) can be pressed onto the valve seat or lifted from the valve seat as required, wherein the valve body (28) acts on a first end segment of a valve shaft (48) by means of a first lever (44) and a control device (56) of the actuating device acts on a second end segment of the valve shaft (48) by means of a second lever (52), wherein the valve shaft (48) is rotatably supported in a region between the first end segment (46) and the second end segment (50). According to the invention, such a wastegate valve (26) is characterized in that the force exerted on the second lever (52) by the control device (56) in order to press the valve body (28) onto the valve seat and the reaction force exerted on the valve body (28) by the valve seat as a result of this pressing are oriented at an angle of less than 90° to each other.

Description

description

Wastegateventilsystem, exhaust gas turbocharger, internal combustion engine and motor vehicle

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 are 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, too 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 usually 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 under

Considering the elasticity of the components: linear contact), which is opposite to a line-shaped (or areal) contacting with a locally significantly increased wear.

To overcome this problem, it is provided in DE 10 2009 048 125 A1 that the valve body of a wastegate valve is fixed between two bearing points on the valve shaft such that the forces exerted by the actuator on the valve shaft on the one hand and the valve body due to the exhaust pressure On the other hand, the forces exerted on the valve shaft are oppositely directed in the bearing points, which is intended to reduce the friction in the bearing points. 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 well-known from DE 10 2009 048 125 A1 storage for the shaft of a wastegate valve is relatively complex and thus expensive and sometimes difficult or under use of a relatively large space in the housing of an exhaust gas turbocharger integrated.

In DE 10 201 1 051 560 A1, a wastegate valve system is shown in which the forces which are exerted on the one hand by an adjusting 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 As a result of this pressing of a valve seat on the valve body and exerted by this 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, from DE 10 201 1 105 997 A1 a wastegate valve system is known in which the forces exerted on the one hand by an actuator for pressing a valve body on a valve seat on a first end of a first lever and on the other hand as reaction force due to this Andrückens from a valve seat on the valve body and exerted by this on a first end of a second lever, 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 case of the regularly occurring design of wastegates with the outlet side of the bypass and in the flow direction of the bypass Exhaust gas flow opening wastegate valve 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 a

Slanting of the shaft within the bearing shell and thus a locally increased wear can be avoided or at least greatly reduced if these forces are no longer opposite but as possible rectified, i. 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 adjusting device of

Actuator via a second lever at a second end portion of the

Valve shaft attacks, wherein the valve shaft (preferably exclusively) is rotatably mounted in a region between the first end portion and the second end portion, according to the invention characterized in that the force exerted by the adjusting device on the second lever for pressing the valve body on the valve seat on the one hand and the by this pressing of the valve seat on the valve body exerted reaction force on the other hand at an angle less than 180 °, preferably less than 90 ° and further advantageous less than 45 ° are aligned. The most advantageous storage of the valve shaft is obtained when these forces are as possible rectified, ie pointing in the same direction and aligned 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, provided that these lines of effect do not intersect, this applies to the projection of the lines of action into the corresponding plane.

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 can be advantageous in particular with regard to the installation space to be provided for the wastegate valve system

Compared to an embodiment in which, for pressing the valve body on the valve seat, a tensile force is exerted by the adjusting device on 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 which can be driven by the turbine and, furthermore, a bypass as required

Turbine impeller of the turbine provided by-pass, 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, the one or more

Forms combustion chambers, as well as a fresh gas line, via the fresh or the combustion chambers can be supplied fresh gas, and an exhaust system, via the exhaust gas from the or Combustion chambers can be discharged, wherein the compressor of the exhaust gas turbocharger in the fresh gas line 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 ("one", "one", "one" and "one"), in particular in the

Claims and in the claims generally explaining the description are to be understood as such and not as numerical words. Correspondingly thus 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 shows schematically an internal combustion engine according to the invention;

Fig. 2: an exhaust gas turbocharger according to the invention, as it is for example in a

Internal combustion engine according to FIG 1 can be used;

3 shows a detail of a horizontal section through the exhaust-gas turbocharger according to FIG. 2;

Fig. 4: schematically the resulting from the inventive design of a

Wastegateventilsystems resulting benefits for the storage of the valve shaft;

Fig. 5: in comparison, the corresponding storage of a valve shaft of a

generic wastegate valve system; and

Fig. 6: an inventive motor vehicle.

The internal combustion engine shown schematically in FIG. 1 comprises a

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 is supplied via a fresh gas train fresh gas, which is used in combustion chambers, which are bounded by the cylinders 12 in conjunction with the piston guided therein and down and a cylinder head (not shown) for the combustion of directly injected fuel. The resulting during combustion exhaust gas is removed via an exhaust line.

In the exhaust system, a turbine 14 of an exhaust gas turbocharger is integrated. A turbine runner (not shown) of the turbine 14 is rotatably driven by the exhaust gas flow, this rotation via a shaft 16 to a compressor wheel (not shown) of one of the

Fresh gas train integrated compressor 18 of the exhaust gas turbocharger is transmitted. The rotation of the compressor impeller causes a compression of the fresh gas and thus an increase in the mass of convertible into the combustion chambers fresh gas. As a result, the filling of the combustion chambers and thus the achievable performance of the internal combustion engine 10 improves.

In order to prevent that part of the filling improvement realized by the compression is compensated by the temperature increase of the fresh gas associated with the compression, a charge air cooler 20 is provided, which cools the compressed fresh gas.

The exhaust gas turbocharger also has a wastegate 22. This includes a the

Turbine wheel bypass bypass 24 and a wastegate valve system 26 according to the invention with a valve body 28, by means of which the downstream outlet opening of the bypass 24 is more or less closed (see Fig. 3), and a

Actuator allowing controlled movement of the valve body 28.

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

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

Compressor housing part 38 starting from one of an inlet port 40 of the Compressor housing part 38 formed inlet flows through to an outlet formed by an outlet 42 of the compressor housing part 38 outlet.

A bypass 24 integrated into the turbine housing part 34 connects the inlet to the outlet of the turbine, bypassing the turbine runner. The outlet opening of the bypass 24 can be closed by means of a flap-shaped valve body 28 (compare FIG. 3). Of the

Valve body 28 is connected via a first lever 44 with a first end portion 46 a

Valve shaft 48 is connected, wherein the first lever 44 and the valve shaft 48 are integrally formed. At a second end portion 50 of the valve shaft 48, a second lever 52 is rotatably connected. This second lever 52 serves to articulate an actuating rod 54 of an adjusting device 56 through which the valve body 28 is pressed either to close the bypass 24 to a valve seat 66 surrounding the outlet opening of the bypass 24 or more or less lifted from this valve seat 66 to defined Flowing subsets of the exhaust gas flow from the inlet into the outlet of the turbine, bypassing the turbine runner.

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

By exerting tensile or compressive forces by means of the actuating device 56 and the actuating rod 54 to the corresponding articulation point of the second lever 52, a movement of the actuating rod 54 is translated into a rotational movement of the valve shaft 48, which in turn to a movement of the valve body 28 in a part-circular path leads, whereby the valve body 28 can be moved either in the direction of the valve seat 66 or away.

For pressing the valve body 28 onto the valve seat 66, the exertion of a compressive force 60 (see Fig. 2) on the second lever 52 by means of the adjusting device 56 and the actuating rod 54 is required. The force with which the valve body 28 is pressed onto the valve seat 66 causes an oppositely directed reaction force which acts on the valve body 28 from the valve seat 66. As a result of the configuration of the wastegate valve system with valve body 28 opening in the direction of flow of the exhaust gas stream, a pressure force, whose level results from the pressure, is added to the reaction force when the valve body 28 rests on the valve seat 66 of the exhaust gas in the region of the inlet as well as the area of the valve body 28 covering the outlet opening. The corresponding total force 62 is also shown in FIG. 2. When partially or completely lifted from the valve seat 66 valve body 28, the force on the valve body 28 results from the pressure and the flow velocity of the exhaust gas in combination with the applied surface of the valve body 28. In Fig. 2 it can also be seen that the the actuator 56 on the second lever 52 pressure exerted force 60 on the one hand and acting on the valve body total force 62 on the other hand, the same 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 (about 20 °). This results in the advantages shown in FIG. 4 in terms of the storage of the valve shaft 48 in the bearing sleeve 58. It is shown between the outside of the valve shaft 48 and the inside of the bearing sleeve 58, a relatively large game, as in many cases for the Storage of wastegate valve systems must be provided in order to achieve a rotatability of the valve shaft 48 in the bearing sleeve 58 over the wide temperature range within which exhaust gas turbochargers are operated.

FIG. 4 shows that substantially rectified forces 60, 62 (of FIG

Actuator 56 exerted pressure force on the one hand and on the valve body 28 acting total force on the other hand) a linear (extending in the longitudinal direction of the valve shaft 48) or large-area contact of the valve shaft 48 with a portion 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 within the bearing bush 58 and thereby a double-point or double-small contact setting (see Fig. 5), the associated with a locally significantly increased wear.

FIG. 6 also shows a motor vehicle according to the invention with an internal combustion engine 64, which is provided for providing the traction drive power, for which purpose mechanical power generated by the internal combustion engine 10 is indirectly transmitted (with the interposition of a transmission) to driven wheels of the motor vehicle. Alternatively (not shown), the mechanical power of the internal combustion engine 10 can also be 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 the driven wheels of the motor vehicle can drive. The internal combustion engine 64 of the motor vehicle can be designed, for example, according to FIG. 1.

LIST OF REFERENCE NUMBERS

internal combustion engine

cylinder

turbine

wave

compressor

Intercooler

wastegate

bypass

Wastegate valve system

valve body

casing

Inlet of the turbine housing part

Turbine casing

Outlet nozzle of the turbine housing part

Compressor housing part

Inlet socket of the compressor housing part Outlet socket of the compressor housing part of the first lever

first end portion of the valve shaft

valve shaft

second end portion of the valve shaft

second lever

actuating rod

locking device

bearing sleeve

thrust

total power

Internal combustion engine

valve seat

Claims

claims

A wastegate valve system (26) for an exhaust gas turbocharger having a valve seat (66) forming a housing (30), a valve body (28) and an actuator by which the valve body (28) as needed on the valve seat (66) can be pressed or lifted from this is, wherein the valve body (28) via a first lever (44) at a first end portion (46) of a valve shaft (48) and an adjusting device (56) of

Actuator via a second lever (52) on a second end portion (50) of the valve shaft (48) engages, wherein the valve shaft (48) is rotatably mounted in a region between the first end portion (46) and the second end portion (50), characterized characterized in that the force exerted by the adjusting device (56) on the second lever (52) for pressing the valve body (28) on the valve seat on the one hand and the reaction force exerted by this pressing of the valve seat (66) on the valve body (28) on the other hand are aligned at an angle smaller than 90 ° to each other.

2. Wastegateventilsystem (26) according to claim 1, characterized in that the forces are oriented at an angle less than 45 ° to each other.

3. Wastegateventilsystem (26) according to claim 1 or 2, characterized in that the forces are rectified.

4. Wastegateventilsystem (26) according to any 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 compressive force on the second lever (52) is exercised.

5. Wastegateventilsystem (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) is rotatably mounted in a bearing opening of the housing (30)

6. Exhaust gas turbocharger with an intended bypassing of a turbine runner provided by-pass (24) and a wastegate valve system (26) according to one of the preceding claims for controlling the quantity of an exhaust gas flow through the bypass (24).

7. Internal combustion engine (64) with an exhaust gas turbocharger according to claim 6.

8. Motor vehicle with an internal combustion engine (64) according to claim 7.