DE102015011146A1 - Turbine for an exhaust gas turbocharger - Google Patents

Abstract

The invention relates to a turbine for an exhaust gas turbocharger, comprising a turbine housing (12) through which at least two fluidically separated fluid passages (14, 16) and at least one overflow opening (18) can flow which the fluids (14, 16) are fluidically connectable to each other, with a in the turbine housing (12) rotatably received and driven by the exhaust turbine wheel, with at least one bypass passage through which the turbine wheel at least to avoid a part of the exhaust gas, and with a valve element (10) rotatable about an axis of rotation (22) relative to the turbine housing (12), having a valve body (24) by means of which a first quantity of the exhaust gas flowing through the bypass channel and a second quantity flowing through the bypass opening (18) Exhaust gases are adjustable, wherein the valve body (24) as Ringseg formed, whose center lies on the axis of rotation (22).

Description

The invention relates to a turbine for an exhaust gas turbocharger.

From the general state of the art and in particular from mass-produced vehicles, it is known to equip internal combustion engines for driving motor vehicles with exhaust gas turbochargers in order to realize efficient operation of the respective internal combustion engine. Such an exhaust gas turbocharger comprises a turbine drivable by exhaust gas of the internal combustion engine and a compressor drivable by the turbine for compressing air. The compressed by means of the compressor air can be supplied to the internal combustion engine. Since the compressor of the turbine and the turbine of the exhaust gas of the internal combustion engine is drivable, energy contained in the exhaust gas can be used to compress the air.

Typically, such a turbine has a turbine housing and a turbine wheel rotatably received in the turbine housing and a bypass passage, via which at least a portion of the exhaust gas can bypass the turbine wheel. This means that the exhaust gas flowing through the bypass channel does not flow against the turbine wheel and consequently does not drive. The bypass channel is also referred to as wastegate or bypass and is used in particular to adjust the boost pressure of the exhaust gas turbocharger.

Object of the present invention is to provide a turbine for an exhaust gas turbocharger, with a particularly advantageous operation of the turbine can be realized.

This object is achieved by a turbine having the features of patent claim 1. Advantageous embodiments with expedient developments of the invention are specified in the remaining claims.

The turbine according to the invention for an exhaust gas turbocharger, in particular an internal combustion engine for driving a motor vehicle, has a turbine housing through which exhaust gas of the internal combustion engine can flow with at least two at least partially fluidically separated from each other and flowed through by the exhaust floods. The turbine housing thus has the floods and at least one overflow opening, via which the floods can be fluidly connected to one another. The turbine further comprises a turbine wheel rotatably received in the turbine housing and driven by the exhaust gas turbine. Furthermore, the turbine has at least one bypass channel over which the turbine wheel is to bypass at least part of the exhaust gas. The exhaust gas flowing through the bypass passage bypasses the turbine wheel and does not flow to the turbine wheel, and accordingly, the turbine wheel is not driven by the exhaust gas flowing through the bypass passage.

In addition, the turbine comprises a rotatable about an axis of rotation relative to the turbine housing valve member having a valve body, by means of which a bypass passage flowing through the first amount of the exhaust gas and the overflow opening flowing through a second amount of the exhaust gas can be adjusted. For example, the bypass channel and / or the overflow opening can be fluidly blocked by means of the valve body, so that no exhaust gas can flow through the bypass channel or the overflow opening. The valve body is designed as a ring segment, the center of which lies on the axis of rotation.

The process of passing exhaust gas through the bypass passage is also referred to as exhaust because the exhaust gas flowing through the bypass passage does not drive the turbine wheel, so that energy contained in exhaust gas flowing through the bypass passage is not used to drive the turbine wheel. Since by means of the valve element, the first amount of the exhaust gas flowing through the bypass channel is adjustable, the blow-off, which is also referred to as blow-off, can be adjusted by means of the valve element. Furthermore, the valve element is used to adjust the second amount and thus the connection of the floods. The valve element thus has a dual function, since it is used on the one hand to set the first quantity and on the other hand to adjust the second quantity. Because of this dual function, the number of parts and thus the weight and the space requirement of the turbine can be kept low, so that a particularly advantageous and efficient operation of the turbine can be realized.

Due to the design of the valve body as a ring segment whose center or center is located on the axis of rotation, also a particularly advantageous and efficient operation of the turbine can be realized because the inflow through the first channel first amount can be kept low, while the floods are particularly strongly interconnected and consequently a high second amount can be set. In other words, by configuring the valve body as a ring segment, it is possible to more strongly balance the connection of the floods than the release of the bypass passage when the valve element and thus the valve body are rotated about the rotation axis. The invention is based on the finding that a particularly efficient operation of the turbine can be realized if the overflow opening is released particularly widely and thus the floods are particularly strongly interconnected, while at the same time blowing is kept as low as possible. By fluidically connecting the floods, for example, a congestion charging of the turbine can be set.

It is conceivable that in at least one closed position of the valve element and thus of the valve body, the overflow opening is fluidly blocked by means of the valve body, so that the floods are separated from each other in the region of the overflow. As a result, for example, an impact charging of the turbine can be set. By the mentioned and by the corresponding design of the valve body as a ring segment realizable, different weighting of the blow-off and connecting the floods, wherein the connecting the floods is emphasized or weighted more than the blow-off, it is possible to demand between the shock charging and the accumulation charge to switch, while the bypass passage flowing through the first amount, that is, the blow-off, can be kept particularly low. Thus, the problem can be avoided or at least minimized that with increasing flood connection also takes an excessive, increasing release of the bypass channel.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination but also in other combinations or in isolation, without the scope of To leave invention.

The drawing shows in:

1a -D respective schematic representations of a valve element for a turbine of an exhaust gas turbocharger in different positions of the valve element;

2 a schematic perspective view of the valve element;

3 a schematic front view of the valve element; and

4 a schematic and perspective side view of the valve element and a part of a turbine housing of the turbine.

In the figures, the same or functionally identical elements are provided with the same reference numerals.

1a shows on the left in a schematic side view and on the right in a schematic sectional view along a section line A as a whole 10 designated valve element for a turbine of an exhaust gas turbocharger. In this case, an internal combustion engine of a motor vehicle, in particular a passenger car, equipped with the exhaust gas turbocharger, the exhaust gas turbocharger comprising the turbine and a compressor. The turbine is arranged in an exhaust tract of the internal combustion engine, wherein the exhaust gas tract of exhaust gas of the internal combustion engine can be flowed through. The compressor is arranged in an intake tract of the internal combustion engine, wherein the intake tract of air, which is sucked by the internal combustion engine, can be flowed through. The air flowing through the intake tract is compressed by means of the compressor, so that a particularly efficient operation of the internal combustion engine can be realized. As will be explained in more detail below, the compressor of the turbine and the turbine of the exhaust gas of the internal combustion engine is driven, so that energy contained in the exhaust gas can be used to compress the air.

The turbine has an in 1 partially recognizable turbine housing 12 on which of the exhaust gas can flow. In synopsis with 3 it can be seen that the turbine housing 12 at least two floods 14 and 16 has, which are traversed by the exhaust gas. The floods 14 and 16 are at least partially fluidly separated from each other and open into a receiving space of the turbine housing 12 , In the fully manufactured state of the turbine, a turbine wheel is rotatably received in the receiving space, so that the floods 14 and 16 flowing exhaust gas by means of the floods 14 and 16 is guided to the turbine wheel. Thus, the exhaust gas flowing into the receiving space can flow to the turbine wheel and thereby drive.

The turbine wheel is part of a rotor of the exhaust gas turbocharger, wherein the rotor also comprises a shaft and a compressor wheel of the compressor. In this case, the compressor comprises a compressor housing in which the compressor wheel is rotatably received. The turbine wheel and the compressor wheel are non-rotatably connected to the shaft so that the compressor wheel can be driven by the turbine wheel via the shaft.

Especially good 1b -D can be seen that the turbine housing 12 at least one overflow opening 18 over which the floods 14 and 16 fluidly connected to each other. In addition, the turbine, in particular the turbine housing 12 , At least one in the Fig. Not recognizable bypass channel over which the turbine wheel is at least to bypass a part of the exhaust gas. This means that the turbine housing 12 For example, has an inflow opening, via which the bypass channel, the exhaust gas from the floods 14 and 16 can be fed. The exhaust gas flowing into the bypass channel via the inlet opening-when it is released-can flow through the bypass channel and thus bypass the turbine wheel, whereby the exhaust gas flowing through the bypass channel does not flow against the turbine wheel and consequently does not drive. This bypassing of the turbine wheel is also referred to as blow-off or blow-off, since energy contained in the exhaust gas flowing through the bypass duct is not used to drive the turbine wheel.

In the finished state of the turbine is the valve element 10 with a wave 20 coupled, the shaft 20 around a rotation axis 22 relative to the turbine housing 12 is rotatable. As the bypass channel also called wastegate and the valve element 10 as wastegate valve is called, the shaft 20 also referred to as Wastegate wave. The valve element 10 is thus about the axis of rotation 22 relative to the turbine housing 12 pivotable or rotatable, wherein the valve element 10 for example, between at least one in 1a illustrated closed position and at least one in 1d illustrated open position relative to the turbine housing 12 is movable. In order to keep the number of parts and thus the weight, the space requirement and the cost of the turbine particularly low, comes the valve element 10 a double function too.

For this purpose, the valve element 10 a valve body 24 on, by means of which a bypass channel flowing through the first amount of the exhaust gas and the overflow opening 18 flowing through the second amount of the exhaust gas are adjustable. in particular, by means of the valve body 24 a first flow cross section through which the exhaust gas can flow through said inlet opening and a second flow cross section of the overflow opening through which the exhaust gas can flow 18 adjustable. This means that both amounts of the exhaust gas by means of a valve element 10 , in particular of the valve body 24 , are adjustable, so not about respective, separate from each other setting elements must be provided for adjusting the amounts.

In order to realize a particularly efficient or advantageous operation of the turbine, the valve body is 24 - how very good 1a and 1c is recognizable - designed as a ring segment whose center on the axis of rotation 22 lies. In the present case, this ring segment has an at least substantially circular cross-section. In other words, the valve element 10 one on the axis of rotation 22 lying pivot point relative to the turbine housing 12 rotatable and thus movable between the open position and the closed position. Here is the valve body 24 formed as a ring portion whose center is located in said pivot point. The pivot point is the point around which the valve element 10 and thus the valve body 24 rotate. The valve element 10 also has one of the valve body 24 projecting pins 26 on, over which the valve element 10 with the wave 20 connected is.

Due to the design of the valve body 24 As a ring segment, it is possible to use the valve element 10 and thus the valve body 24 from the closed position successively to move in the direction of or in the open position, while the overflow 18 continue to release and thus the floods 14 and 16 continue to connect, while the inflow opening or the second flow cross-section can be kept particularly low and in particular not or only slightly further increases. The flow cross-section of the bypass channel or the inflow opening is also referred to as Abblasefläche, since the exhaust flow through this Abblasefläche in the bypass channel and thus can bypass the turbine wheel. In other words, it is due to the described embodiment of the valve body 24 possible to connect the floods more and more with each other by the overflow opening 18 is released further, while at the same time an increase, in particular an excessive increase, the Abblasefläche is omitted.

The Abblasefläche, which can be traversed by the exhaust gas and through which the exhaust gas can flow into the bypass channel, for example, a gap between an in 1a designated B first surface and one in 1a crosshatched second area C. In the in 1a shown closed position is the inlet opening fluidly blocked, so that the bypass channel is completely closed. In the closed position not only the inflow or the bypass channel is thus fluidly blocked, but in the closed position are also the floods 14 and 16 fluidly separated from each other.

1b and 1c show intermediate positions of the valve element 10 between the closed position and the open position, wherein the second flow cross section is substantially larger than the first flow cross section. This means that the floods 14 and 16 Although fluidly interconnected, but the gap between the surfaces B and C and thus the Abblasefläche are particularly low. In the closed position and in the intermediate positions is - how very good 4 recognizable - the valve body 24 at least partially received in the inflow opening, which through at least one wall 28 of the turbine housing 12 is limited. As a result, the Abblasefläche in the intermediate positions by the valve body 24 , in particular an outer peripheral side surface 30 of the valve body 24 , and the wall 28 limited.

By further moving the valve body 24 from the in 1c and 4 shown intermediate position in the open position, the valve body 24 completely moved out of the inflow opening, so that the valve body 24 is arranged completely outside the inlet opening in the open position. Then the inflow opening or the Abblasefläche is no longer through the wall 28 and the outer peripheral side surface 30 , but only through the wall 28 limited, so that the inflow opening is fully released, for example. To the valve body 24 from the in 1c and 4 shown intermediate position to move in the open position, in particular to turn, the valve element 10 for example, 3 degrees around the axis of rotation 22 turned.

The embodiment of the valve body 24 as a ring segment is particularly good 1a and 1c recognizable. The valve body 24 follows in terms of its course or in terms of its extent a circle 33 or a segment of the circle 33 whose center is on the axis of rotation 22 or on the said pivot point. This makes it - as described above - possible, the release of the overflow 18 and thus connecting the floods 14 and 16 to emphasize against blowing off or connecting the floods 14 and 16 weight more than blowing off. As a result, excessive blow-off can be avoided while the floods 14 and 16 over the overflow opening 18 particularly strong or wide or large area can be connected to each other.

Based on the flow direction of the exhaust gas through the floods 14 and 16 is the overflow opening 18 upstream of the turbine wheel, so when releasing the overflow 18 that is with interconnected floods 14 and 16 Exhaust from the tide 14 into the flood 16 over the overflow opening 18 can flow or vice versa. As a result, a bump charging or a bump charging operation of the turbine can be realized. Is the overflow opening 18 by means of the valve body 24 fluidly obstructed so that the overflow 18 is not released, so for example, a shock charging or a shock charging operation of the turbine is set.

Especially good 1b it can be seen that the valve body 24 at least a first sealing surface 32 for fluidic blocking of the overflow opening 18 and at least one of the first sealing surface 32 spaced, second sealing surface 34 for fluidically blocking the bypass channel. In this case, preferably, the second sealing surface 34 on a larger diameter than the first sealing surface 32 arranged. In the closed position, the sealing surfaces act 32 and 34 with respective, corresponding sealing surfaces of the turbine housing 12 together by the sealing surfaces 32 and 34 for example, on the corresponding, further sealing surfaces of the turbine housing 12 issue.

LIST OF REFERENCE NUMBERS

10

valve element

12

turbine housing

14

flood

16

flood

18

overflow

20

wave

22

axis of rotation

24

valve body

26

spigot

28

wall

30

outer peripheral side surface

32

sealing surface

33

circle

34

sealing surface

A

intersection

Claims (4)

Turbine for an exhaust-gas turbocharger, with a turbine housing through which exhaust gas from an internal combustion engine can flow ( 12 ), which at least two at least partially fluidly separated from each other and by the exhaust gas flowable floods ( 14 . 16 ) and at least one overflow opening ( 18 ) over which the floods ( 14 . 16 ) are fluidically connectable to one another in the turbine housing ( 12 ) rotatably received and driven by the exhaust gas turbine wheel, with at least one bypass channel through which the turbine wheel is at least to avoid a part of the exhaust gas, and with a about an axis of rotation ( 22 ) relative to the turbine housing ( 12 ) rotatable valve element ( 10 ), which has a valve body ( 24 ), by means of which a first amount of the exhaust gas flowing through the bypass channel and an overflow opening ( 18 ) are adjustable by the second amount of the exhaust gas, wherein the valve body ( 24 ) formed as a ring segment whose center on the axis of rotation ( 22 ) lies. Turbine according to claim 1, characterized in that the ring segment has a circular cross-section. Turbine according to claim 1 or 2, characterized in that the valve body ( 24 ) at least one first sealing surface ( 32 ) for fluidic blocking of the overflow opening ( 18 ) and at least one of the first sealing surface ( 32 ) spaced, second sealing surface ( 34 ) for fluidically blocking the bypass channel. Turbine according to one of the preceding claims, characterized in that a through at least one wall ( 28 ) of the turbine housing ( 12 ) is provided via which the exhaust gas from the floods can be fed to the bypass channel, wherein the valve body ( 24 ) in at least a first position, in which the valve body ( 24 ) the overflow opening ( 18 ), at least partially received in the inflow opening and in at least one of the first position different, second position in which the valve body ( 24 ) the overflow opening ( 18 ), is arranged completely outside the inlet opening.

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