WO2017012686A1

WO2017012686A1 - Turbine for a turbocharger of an internal combustion engine

Info

Publication number: WO2017012686A1
Application number: PCT/EP2016/001087
Authority: WO
Inventors: Siegfried Sumser; Thomas Streule; Patrick Nisius; Paul Loeffler
Original assignee: Daimler Ag
Priority date: 2015-07-21
Filing date: 2016-06-25
Publication date: 2017-01-26
Also published as: DE102015009446A1

Abstract

The invention relates to a turbine (38) for a turbocharger of an internal combustion engine (10), comprising a turbine housing that has a receiving area, in which a turbine wheel (40) can be received in a rotatable manner about a rotational axis (24) relative to the turbine housing, and at least two spiral channels (46, 48), which run in the circumferential direction of the receiving area over the circumference thereof, through which exhaust gas of the internal combustion engine (10) can flow, and which open into the receiving area via respective outlet openings (94, 96) that follow one another in the circumferential direction of the receiving area. The turbine also comprises an adjusting device (70) that has a blocking element (90, 92) for each opening (94, 96), said blocking element being movable about the rotational axis (24) relative to the turbine housing and being used to adjust a flow cross-section of the respective outlet opening (94, 96), wherein exhaust gas flows through the flow cross-section. The spiral channels (46, 48) are designed symmetrically to each other and extend over the same wrap-around angle. The blocking elements (90, 92) have the same length or different lengths, which extend in the circumferential direction of the receiving area.

Description

Turbine for an exhaust gas turbocharger of an internal combustion engine

The invention relates to a turbine for an exhaust gas turbocharger according to the preamble of patent claim 1.

Such a turbine is already known, for example, from DE 10 2008 039 085 A1. The turbine includes a turbine housing having a receiving space in which a turbine wheel about a rotational axis relative to the turbine housing is rotatably receivable. The turbine housing further comprises at least two in the circumferential direction of the receiving space extending over the circumference and exhaust gas of the

Internal combustion engine through-flowable spiral channels, which open via respective successive in the circumferential direction of the receiving space outlet openings in the receiving space. As a result, the exhaust gas flowing through the spiral channels is guided by means of the spiral channels to the receiving space, wherein the exhaust gas can flow into the receiving space via the outlet openings. This allows the exhaust gas received in the finished state of the turbine in the turbine housing

Turbine wheel flow and thereby drive.

The turbine further comprises an adjusting device which has an outlet opening which is displaceable about the axis of rotation relative to the turbine housing, by means of which a flow cross-section, through which the exhaust gas can flow, of the respective associated outlet opening is adjustable. In other words, the

Adjusting means on a first locking body, which a first of the

Associated with outlet openings. Furthermore, the adjusting device comprises a second blocking body, which is associated with the second outlet opening. The blocking bodies may, for example, together about the axis of rotation of the turbine wheel relative to the

Turbine housing can be rotated or shifted, whereby a respective, flowed through by exhaust flow cross section of the respectively associated

Outlet opening set, that can be increased or decreased. The Locking bodies are formed for example in the form of tongues, so that the

Adjustment device is also referred to as a tongue slider.

The continuous tightening of emission limit values, in particular with regard to the NO _x and soot emissions, results in a strong influence on the supercharging system of an internal combustion engine. Under such a charging system is a charging device to understand, which comprises at least one exhaust gas turbocharger, by means of which the internal combustion engine can be supplied with compressed air. Due to the growing demands regarding the

Boost pressure provision due to high EGR rates over the medium load range to full load out is usually forced, the turbines of such

Charge systems more and more downsize geometrically. The required high turbine outputs are thus by increasing the Aufstaufähigkeit

or by reducing the absorption capacity of the turbines in the

Realized interaction with the relevant internal combustion engine.

Furthermore, the inlet pressure level of the turbines is further driven upwards by the backpressure of soot filters, whereby the turbines must again be designed to smaller values and thus with lower efficiencies in order to meet the power requirement of the compressor side for the air exhaust gas delivery.

As a core component for the exhaust gas recirculation system has become

Internal combustion engines, especially for commercial vehicles, enforced the twin-flow, asymmetric turbine. A major problem with EGR capability in conjunction with the required combustion air to deliver

Internal combustion engine consists in particular in the lower to middle

Motor operating range and at high load. At the usual design boundary conditions, which also from the nominal point of the internal combustion engine of the

Charge change side and consumption side are defined, so can not be optimally operated in an asymmetrical, double-flow fixed geometry turbine, the lower engine speed range.

In order to be able to optimally set the ratio of the EGR rates to the necessary air-fuel ratio numbers in a larger operating range, a double-flow turbine type would be helpful, which in terms of the impact charging capability at a

Cylinder summary group is more pronounced. Turbines specifically for the Shock charge are designed to have significantly larger flow areas for the recovery of larger usable Exergieschwankungen or

Pressure pulsations. These high pressure pulsations of the internal combustion engine exist and arise at the turbine then, if one of the usually adjusting throttle and friction losses on the exhaust valves and the

Manifold area significantly reduced by a corresponding geometry design into the turbine inside. Reducing the aforementioned throttling and frictional losses upstream of the turbine furthers the achievement of the objective of the desired extreme boost charging, thereby achieving an increase in the average overall efficiency of exhaust energy utilization, despite large temporal variations in turbine efficiency.

The key to the realization of a weighting of the bumping offers the turbine type segment turbine, which with a variability essential

Flow cross-sections should be provided to even in the upper

Engine speed range to be able to exist. This means that the turbine described above with the in the circumferential direction of the receiving space sequentially

or successively arranged outlet openings such

Segmented turbine is, wherein the spiral channels are also referred to as segments or segment channels. The variability mentioned is represented by the adjusting device or the tongue slide, by means of which the

Flow cross sections can be adjusted as needed.

Usually, such a segment turbine is designed asymmetrically with regard to its spiral channels. This means that the spiral channels usually differ from each other in terms of their geometry and in terms of their wrap angle, over which extend the respective spiral channels in the circumferential direction of the receiving space over its circumference.

Object of the present invention is to develop a turbine of the type mentioned in such a way that the cost of the turbine can be kept particularly low while achieving a particularly high robustness of the turbine.

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. In order to further develop a turbine of the type specified in the preamble of patent claim 1 such that the cost of the turbine can be kept particularly low while realizing a particularly high and in particular mechanical robustness of the turbine, it is inventively provided that the spiral channels are formed symmetrically to each other and extend over the same wrap angle. In this case, the blocking bodies have the same length extending in the circumferential direction of the receiving space or unequal lengths extending in the circumferential direction of the receiving space. In other words, the turbine designed as a segment turbine according to the invention is designed as a symmetrical segment turbine, in which the spiral channels, in particular with respect to their respective exhaust gas permeable cross section, are symmetrical to each other and consequently have the same geometry.

In addition, the spiral channels, which are also referred to as segment channels or segments extend in the circumferential direction of the receiving space over its circumference over the same angle of wrap. For example, if the turbine has exactly two spiral channels, the wrap angle of the respective spiral channel is 180 degrees. In addition, it is inventively provided that the example formed as tongues locking body are the same length or have unequal lengths. This makes it possible to create a turbine, which is particularly well suited for mass production and also allows a particularly high variety of applications, which is also determined by space aspects. In addition, the cost of the turbine according to the invention can be kept particularly low while

Realization of an advantageous mechanical and thermodynamic adaptability.

Although the spiral channels are formed symmetrically to each other and have the same wrap angle, it is possible by means of, for example, as

Tongue slider trained adjusting device to realize asymmetry or asymmetric operation of the turbine. In other words, the adjusting device determines the degree of asymmetry of the turbine, which can be operated symmetrically in the limiting case even with the same length of the locking body. However, it has proven particularly advantageous if the blocking bodies have unequal lengths. This makes it possible, the outlet openings or their

Set flow cross-sections asymmetrical to each other, for example, by the blocking body in the radial direction between fixed walls of the

Turbine housing and the turbine wheel shifted about its axis of rotation

or rotated. The mentioned walls are also called Designated housing tongues, for example, when the turbine housing has exactly two spiral channels, have a pitch of 180 degrees-180 degrees.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing. The features mentioned above in the description and

Feature combinations as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures are not only in the respectively indicated combination but also in others

Combinations or alone, without departing from the scope of the invention.

The drawing shows in:

Fig. 1 is a schematic representation of an internal combustion engine for a

Car, with a turbine designed as a segment turbine, the symmetrical to each other and about the same

Has wrapping angle extending spiral channels;

FIG. 2 shows a detail of a schematic longitudinal sectional view of the turbine; FIG.

3 is a diagram for illustrating respective flow cross sections of the spiral channels;

4 shows a detail of a schematic cross-sectional view of the turbine

according to a first embodiment

5 is a diagram for illustrating the operation of the turbine according to the first embodiment; and

6 shows a detail of a schematic cross-sectional view of the turbine

according to a second embodiment.

In the figures, identical or functionally identical elements are provided with the same reference numerals. Fig. 1 shows a schematic representation of a designated as a whole with 10 internal combustion engine for driving a motor vehicle. The

Internal combustion engine 10 has a cylinder housing 12, through which at least one combustion chamber not recognizable in FIG. 1 is formed, in particular in the form of a cylinder. In the present case, the internal combustion engine 10 has at least one first cylinder and at least one additionally provided second cylinder. In particular, it can be provided that the internal combustion engine 10 has a plurality of first cylinders and a plurality of second cylinders. The first cylinders form a first cylinder group, wherein the second cylinder form a second cylinder group.

In the respective cylinders fuel, especially liquid fuel, and air are introduced. For this purpose, the internal combustion engine 10 comprises an air intake through the ble intake section 14 through which the internal combustion engine 10 sucks the air from the environment during its operation. In the intake tract 14, an air filter 16 for filtering the air is arranged.

The internal combustion engine 10 further comprises an exhaust gas turbocharger 18, which has a compressor 20 arranged in the intake tract 14. The compressor 20 comprises a compressor housing, not visible in FIG. 1, and a compressor wheel 22, which is rotatably arranged in the compressor housing. This means that the compressor wheel 22 is rotatable about an axis of rotation 24 relative to the compressor housing. The sucked by the internal combustion engine 10 and the intake tract 14 by flowing air is by means of the compressor 20, in particular by means of the

Compressor wheel 22, compressed and thereby heated. To a particularly high

To realize the degree of supercharging, a cooling device in the form of a charge air cooler 26 is arranged in the intake tract 14 downstream of the compressor 20, by means of which the compressed and thus heated air is cooled. In addition, an intake module in the form of a charge air distributor 28 is arranged in the intake tract 14. By means of the

Charge air distributor 28, the compressed and also referred to as charge air air is distributed to the respective cylinders, so that the compressed air (charge air) on the

Charge air distributor 28 flows into the cylinder.

The fuel is injected for example by means of respective injectors directly into the cylinder. From this supply of fuel and air into the respective cylinder results in the respective cylinder, a fuel-air mixture, which is ignited. Ignition occurs, for example, by spark ignition or auto-ignition. The Internal combustion engine 10 is designed for example as a diesel engine. However, the foregoing and following embodiments may be readily applied to other internal combustion engines.

From the combustion of the fuel-air mixture results in the exhaust gas

Internal combustion engine 10. The internal combustion engine 10 in this case comprises an exhaust tract 30 through which the exhaust gas can flow, by means of which the exhaust gas is discharged from the respective cylinders. In the exhaust tract 30, an exhaust manifold 32 is arranged, by means of which the first cylinder to a first flood 34 and the second cylinder are brought together to form a second flood 36 of the exhaust tract 30. The first flow 34 can be traversed by exhaust gas from the first cylinders, but not by exhaust gas from the second cylinders, wherein the second flow 36 of exhaust gas from the second cylinders, but not exhaust gas from the first cylinders can be flowed through. The floods 34 and 36 are at least partially fluidly separated from each other.

The exhaust-gas turbocharger 18 furthermore comprises a turbine 38 arranged in the exhaust-gas tract 30, which has a turbine housing which is not recognizable in FIG. 1 and in which

Turbine housing rotatably mounted turbine wheel 40 includes. The turbine wheel 40 is rotatable about the axis of rotation 24 relative to the turbine housing. The

Turbine housing has a receiving space in which the turbine wheel 40 is received. The compressor wheel 22 and the turbine wheel 40 are components of a generally designated 42 rotor of the exhaust gas turbocharger 18. The rotor 42 includes a shaft 44, with which the compressor wheel 22 and the turbine wheel 40 are rotatably connected. The turbine wheel 40 arranged in the exhaust tract 30 can be driven by the exhaust gas of the internal combustion engine 10, wherein the compressor wheel 22 can be driven by the turbine wheel 40 via the shaft 44. As a result, the air is compressed by means of the compressor wheel 22, so that the energy contained in the exhaust gas for

Compressing the air can be used.

In the present case, the turbine 38 is designed as a double-flow turbine and consequently comprises two at least partially separated flows 46 and 48, wherein the flow 46 is fluidically connected to the flow 34 and the flow 48 is fluidically connected to the flow 36. As a result, the exhaust gas flowing through the tide 34 can flow out of the tide 34 and flow into the tide 46, wherein the exhaust gas flowing through the tide 36 can flow out of the tide 36 and flow into the tide 48. The exhaust gas flowing through the floods 46 and 48 may eventually flow to and drive the turbine wheel 40. The floods 46 and 48 are two in the circumferential direction of the receiving space extending over the circumference and exhaust gas from the internal combustion engine through which flow through the spiral channels, which via respective, in the circumferential direction of the receiving space

successive outlet openings 94 and 96 (FIG. 4) open into the receiving space. The outlet openings are for example also called nozzles.

The turbine 38 further comprises a particularly schematically illustrated in Fig. 1

Adjusting device 70, which is designed here as a tongue slider. The

Adjusting device comprises per outlet 94 and 96 respectively a displaceable about the axis of rotation 24 relative to the turbine housing locking body 90 or 92, by means of which a flow-through of the exhaust gas

Flow cross section of the respectively associated outlet opening 94 and 96 is adjustable. For example, an actuator, not shown in FIG. 1, is provided by means of which the blocking bodies 90 and 92 are movable, that is to say displaceable about the axis of rotation 24, in order thereby to set the flow cross sections of the outlet openings 94 and 96.

In the exhaust system 30 downstream of the turbine 38, in particular of the turbine wheel 40, an exhaust aftertreatment device 50 of the internal combustion engine 10 is arranged. The exhaust gas flowing through the exhaust tract 30 is by means of

Exhaust after-treatment device 50 post-treated before it is discharged, for example, to the environment. The exhaust aftertreatment device 50 comprises, for example, at least one soot filter, by means of which soot particles can be filtered out of the exhaust gas. Alternatively or additionally, the

Exhaust after-treatment device 50 a catalyst, in particular an SCR catalyst (SCR - selective catalytic reduction) include. By means of such an SCR catalyst, the exhaust gas can be denoxed or de-nitrogenized. This means that nitrogen oxides (NO _x ) can be removed from the exhaust gas by means of the SCR catalytic converter. For this purpose, for example, a reducing agent, in particular in the form of an aqueous urea solution in the exhaust system 30, in particular the

Exhaust gas aftertreatment device 50, metered.

In the cylinders, respective pistons are received translationally movable. The pistons are articulated via respective connecting rods with a crankshaft 52 formed as

Output shaft of the internal combustion engine 10 is coupled so that due to the articulated coupling, the translational movements of the piston in a rotary Movement of the crankshaft 52 can be converted. This rotational

Movement of the crankshaft 52 is illustrated in FIG. 1 by a directional arrow 54.

The internal combustion engine 10 further includes one in the exhaust tract 30

arranged temperature sensor 56, by means of which a temperature of the exhaust gas or the exhaust gas aftertreatment device 50 can be detected. The

Temperature of the exhaust aftertreatment device 50 is also referred to as the operating temperature and T _AGN .

The internal combustion engine 10 includes in the illustrated in Fig. 1

Embodiment optionally an exhaust gas recirculation device 58, by means of which a

Exhaust gas recirculation (EGR) is feasible. However, the exhaust gas recirculation device 58 may also be omitted, so that the internal combustion engine 10 no

Exhaust gas recirculation device comprises.

The exhaust gas recirculation device 58 comprises at least one exhaust gas recirculation line 60, which is connected to the exhaust tract 30 at a branching point. In the present case, the exhaust gas recirculation line 60 is fluidically connected to the flow at the branching point. The exhaust gas recirculation line 60 is also fluid at a feed point with the

Intake tract 14 connected. As a result, at least part of the exhaust gas flowing through the flow 34 can be branched off at the branching point. The exhaust branched off at the branch point flows into the exhaust gas recirculation line 60 and flows through the exhaust gas recirculation line 60. The exhaust gas flowing through the exhaust gas recirculation line 60 is led to the supply point by means of the exhaust gas recirculation line 60 and can flow into the intake tract 14 at the feed point. The incoming into the intake tract 14,

recirculated exhaust gas is by means of the intake 14 flowing through the air

taken and transported in the cylinder.

The exhaust gas recirculation device 58 includes an exhaust gas recirculation line 60

arranged valve element 62, which is also referred to as EGR valve (exhaust gas recirculation valve). By means of the valve element 62 is an amount of the

Exhaust gas recirculation line 60 by flowing exhaust gas adjustable. Furthermore, the exhaust gas recirculation device 58 comprises a disposed in the exhaust gas recirculation line 60

Cooling device 64, which is also referred to as EGR cooler (exhaust gas recirculation cooler). The cooling device 64 is in the flow direction of the exhaust gas through the

Exhaust gas recirculation line 60 disposed downstream of the valve element 62 and formed for cooling the recirculating exhaust gas. Furthermore, the internal combustion engine 10 includes a computing device 66, which is also referred to as a control unit or engine control unit. By means of

Computing device 66, the internal combustion engine 10 is operated, in particular controlled or regulated. In the present case, the computing device 66 is connected to the valve element 62, so that the valve element 62 can be actuated by the computing device 66. This driving means that the valve element 62 is operated by means of the computing device 66, so that the amount of exhaust gas flowing through the exhaust gas recirculation line 60 can be adjusted by means of the computing device 66 via the valve element 62. Furthermore, the computing device 66 is connected to the temperature sensor 56, so that the temperature sensor 56 a the detected temperature of

Exhaust after-treatment device 50 provides characterizing signal. This signal is transmitted to the computing device 66 and received by the computing device 66. Further, for example, a not visible in Fig. 1 speed sensor is provided by means of which the rotational speed of the crankshaft 52 can be detected

or is recorded. The speed sensor provides a rotational speed signal characterizing the detected rotational speed of the crankshaft 52, which - as the

Speed sensor is coupled to the computing device 66 - transmitted to the computing device 66 and received by the computing device 66. This makes it possible that by means of the computing device 66 components of

Internal combustion engine 10 is controlled in dependence on the temperature detected by the temperature sensor 56 and / or in dependence on the speed detected by the speed sensor and thus operated, that is controlled or controlled, are. In particular, it is provided that the valve element 62 of the

Computing device 66 in dependence on the detected temperature of the

Exhaust gas aftertreatment device 50 and / or controlled in dependence on the detected speed, that is regulated or controlled, is.

The exhaust aftertreatment device 50 has an advantageous temperature range or an advantageous operating temperature, in which or at which the exhaust gas can be aftertreated particularly effectively by means of the exhaust gas aftertreatment device 50. This temperature range is for example several hundred degrees, so that the exhaust aftertreatment device 50, for example, during a cold start or immediately after such a cold start of

Internal combustion engine 10 is not in the advantageous temperature range. To heat the exhaust gas and over this the exhaust aftertreatment device 50 particularly quickly and thus bring in a short time in the temperature range, is the Computing device 66 (engine control unit) designed to cause a heating operation of the internal combustion engine 10. In this heating operation, a higher temperature of the exhaust gas is set by means of the computing device 66 than in a normal operation of the internal combustion engine 10 subsequent to the heating operation.

The internal combustion engine 10 has an engine brake device 68, which comprises at least one constant throttle 78. From Fig. 1 it can be seen that in the present case two constant throttles 78 are provided. A first of the constant throttles 78, for example, associated with exactly one of the first cylinder, the second

Constant throttle 78, for example, is associated with exactly one of the second cylinder. Via the respective constant throttle 78, gas can be supplied to the respective cylinder, in particular in the form of air, as well as gas can be discharged from the respective cylinder. In other words - when the constant throttle 78 is released - gas, in particular air, are pushed out by means of the respective piston from the respective cylinder via the respective constant throttle 78 and sucked into the respective cylinder.

The respective cylinder gas exchange valves in the form of intake valves and exhaust valves are also assigned. By means of these gas exchange valves, the so-called gas exchange of the respective cylinder is controlled. By this is meant that the air can flow into the respective cylinder, for example, when the inlet valves are opened. If the exhaust valves are open, then the respective piston can push out the respective exhaust gas from the respective cylinder via exhaust ducts.

The respective constant throttle 78 is in addition to the respective

Gas exchange valves provided and facing the intake ports and

Outlet channels a much lower, can be traversed by the gas

Flow cross section, so that through the respective constant throttle 78 a

Engine brake in the form of a decompression brake can be displayed. By means of the

Constant throttles 78 comprehensive engine braking device 68 is an engine braking operation or an engine brake feasible. In the engine braking operation, the respective constant throttle 78 with a particularly small cross section is parallel to the

For example, exhaust valves are opened not only at the end of the compression stroke but during the entire engine braking operation. This results in a

Decompression of the compressed by the respective piston gas continuously, but due to the small cross-section of the respective constant throttle 78 at high back pressure. Also in the following expansion phase is a high engine braking effect present, since the gas flows against the resistance of the respective constant throttle 78 in the respective cylinder or is sucked.

For example, the motor brake device 68 also includes the tongue slide (adjusting device 70), so that the tongue slide for effecting the

Engine brake can be used. In this case, the engine brake device 68th

for example, also referred to as turbo bolter.

It has been found that the turbobrake has a particularly high potential for generating high amounts of air and negative charge changes, ie high

Motor back pressure has, whereby a particularly rapid heating or warming of the exhaust tract 30 and thus the exhaust aftertreatment device 50 can be realized. In addition, the turbo bolte has a particularly high robustness against high exhaust gas mass flows and high heat transfer coefficients.

In order to carry out the described heating phase in a particularly efficient and effective manner, that is to say the exhaust gas tract 30 or the exhaust gas and over this the

Exhaust gas aftertreatment device 50 with a low fuel cost and to heat up quickly in a short time, the computing device 66 is adapted to cause the Aufheizbetriebs the motor brake device 68, that is the respective constant throttle 78 and the actuator or the adjusting device 70 to control. In other words, it is intended to use the turbo engine for a

Co-use heating method of the exhaust tract 30. The turbobrake thus has a dual function, since it is used on the one hand for effecting the engine braking operation and on the other hand for effecting the heating operation. The heating process or the heating operation can thus take place even at relatively low engine loads, whereby high absolute amounts of heat can be generated, the good due to the increased amounts of exhaust gas and flow rates

Heat transfer coefficients for the overflow surfaces of the components to be heated of the exhaust tract 30 and the exhaust aftertreatment device 50 are caused.

At least the constant throttles 78 acting as engine brake valves serve to influence the engine efficiency and the turbocharger efficiency. Due to the robustness of the turbine 38 with the turbine wheel 40 embodied, for example, as a customized Dickschaufler turbine wheel, the turbine 38 also tolerates inlet pressures of more than 10 bar without mechanical problems a desired high heating potential, the usual turbines with variable turbine geometry already due to the mechanical functionalities for controlling the relevant pressure pulsation and the gas force effects is far from available.

The heating operation is for example by a special heating control

accomplished, which is carried out by means of the computing device 66, which activates or deactivates the corresponding actuators or the respective components. Depending on the motor operating points of the heating phases to be traveled, there are manifold possible combinations of the components in the form of the constant throttles 78, of fuel injection times, the adjusting device 70 and / or the

Regulating device with respect to their positions, since the adjusting device can be moved, for example stepped or continuously in different positions. Of the

Control algorithm is compared to the setpoints of the characteristic

Temperatures T _AGN in the exhaust aftertreatment device 50 and the absolute heat quantities H _{AGN of} the exhaust gas in the exhaust system 30 on the fuel injection quantities for the achievement of time-dominated optimization goals control. Here, according to the task given by nature unterschieoev ^ whether the denoxification by rapid heating or the soot filter burning with still high

Oxygen quantities should be optimally served.

The constant chokes 78 are coupled to the computing device 66 and thus can be controlled by the computing device 66. The constant throttles 78 can thus be opened and closed by means of the computing device 66. In the open state, the constant throttle 78 can be traversed by the described gas, wherein the gas in the closed state of the constant throttle 78 can not flow through it.

The turbine 38 of the exhaust gas turbocharger 18 is as a segment turbine or

Multi-segment turbine formed. The turbine housing in this case has exactly two in the circumferential direction of the receiving space over its circumference at least in the present case

Substantially spirally running and exhaust gas from the internal combustion engine through-flowable spiral channels in the form of the floods 46 and 48 which, via the respective, in the circumferential direction of the receiving space consecutive

or successively arranged outlet openings 94 and 96 open into the receiving space. The exhaust gas flowing through the spiral channels can the

Outlet openings 94 and 96 flow through and thus flow out of the spiral channels and flow into the receiving space. As a result, the exhaust gas flowing out of the spiral channels can flow against the turbine wheel 40 and thereby drive it. The outlet openings 94 and 96 are also referred to as nozzles, wherein in Fig. 2 schematically in Fig. 2 with 80 designated nozzle of the first spiral channel (flood 46) is shown. The respective nozzle is also referred to as a tongue slide nozzle.

The adjusting device 70 is a tongue slide, which per outlet opening 94 and 96 has a about the axis of rotation 24 relative to the turbine housing rotatable or movable or movable locking body 90 or 92 in the form of a tongue. By means of this blocking body 90 or 92 or by means of this tongue, a flow cross-section through which the exhaust gas can flow is assigned to the respective associated outlet opening 94 or 96. In other words, the tongue slider has a first locking body 90 or a first tongue which is associated with the first outlet opening 94 (nozzles). Further, the tongue slider comprises a second locking body 92 and a second tongue associated with the second outlet opening 96 (nozzle). If the first blocking body 90 is rotated about the axis of rotation 24, then the flow cross section of the first outlet opening 94 is thereby set. If the second locking body 92 is rotated about the axis of rotation 24, so is the

Flow cross-section of the second outlet opening 96 is set. It can be provided that the locking body 90 and 92 are rotatable relative to each other or independently of each other about the axis of rotation 24. Preferably, it is also provided that the locking bodies 90 and 92 are held on a common ring and rotatable about this ring about the rotation axis 24 relative to the turbine housing, in particular by means of the actuator.

In Fig. 2, a turbine blade 82 of the turbine wheel 40 is further recognizable. The

Turbine blade 82 has a leading edge 84, via which the turbine blade 82 is flowed by the exhaust gas during operation of the turbine 38. The particularly well visible in Fig. 2, extending in the axial direction of the turbine 38 extending the

Leading edge 84, which is also referred to as the leading edge, is a so-called inflow width, through which the turbine blade 82 is flown by the exhaust gas. Since the outlet ports 94 and 96 are arranged one behind the other in the circumferential direction, the entire inlet width can be used to supply the exhaust gas to the turbine blade 82.

In order to keep the cost of the turbine 38 is particularly low and to realize a particularly high robustness of the turbine 38, it is provided that the spiral channels are formed symmetrically to each other and over the same Extend wrapping angle. In this case, the blocking bodies 90 and 92 are designed, for example, such that they have the same length extending in the circumferential direction of the receiving space or unequal lengths extending in the circumferential direction of the receiving space. The spiral channels are also referred to as segments or spiral segments. Thus, the turbine 38 is a segmented turbine or

honor segment turbine trained.

Usually, such multi-segment turbines are designed asymmetrically with tongue slides. This means that the spiral segments are formed asymmetrically to each other. The function of this simple turbine is based on the rotary valve principle, in which the respective tongue tips the relevant

Tapping spiral flow cross-section and thus influence the entry spin speed or turbine power weighty. The robust construction with only a small number of moving parts makes this type of turbine particularly suitable for commercial vehicle applications that have high demands on a reliable adjustment function over many 100,000 kilometers. The application of the emerging gasoline engine supercharging, which will evolve towards variable turbine geometries, should also make this design very significant.

From Fig. 1 it can be seen that the exhaust gas recirculation line 60 fluidly connected to the flood 34, but not with the flood 36 / Therefore, the flood 34 is also referred to as EGR flood, so that the flood 46, in which the flood 34 opens , also referred to as EGR segment, EGR channel or EGR line. This means that the flood 34 and the flood 46 are used in particular to provide a sufficiently high amount of recirculating exhaust gas and thus a sufficiently high EGR rate. In contrast, the flood 36 and the flood 48 in particular the task, the

Setting the combustion air ratio λ to desired values, so that the flood 36 is also referred to as lambda flood. Accordingly, the flood 48 is also referred to as lambda spiral channel, lambda segment or lambda line.

The adjusting device 70 designed as a tongue slider is a variability by means of which the turbine 38 can be adapted as needed to different operating points. Therefore, the turbine 38 is also referred to as a Vario-segment turbine. Since the flood 34 is an EGR flood, the first cylinder group is a so-called EGR cylinder group to which the flood 34 is connected. The EGR cylinder group

accomplishes the exhaust gas recirculation via the cooling device 64 to the air side using the Aufstaufähigkeit the relevant turbine segment in the form of the flood 46 or the intake tract 14. The designed as a tongue slide turbine turbine 38 as well as the exhaust gas recirculation valve (valve element 62) are controlled by a scheme with stored and applied electronic data on optimal behavior in terms of consumption and emission.

For a quick response of the exhaust aftertreatment system in the form of

Exhaust gas aftertreatment device 50 may be the control of the designated also as a Vario turbine turbine 38 with the exhaust gas recirculation valve as well as the respective

Constant throttle 78 in the respective cylinder in the context of thermal management are carried out very effectively.

As evidenced by the development activities of a supercharged engine braking system with the turbo bolter, the robust, variable engine is expected to be used

Tongue slider turbine the otorbremssystem very much over the prior art vorteilt be, if the small constant throttle valves (constant throttles 78) mitbefliegen in the cylinders and are opened in the engine braking phases.

The respective outlet openings 94 and 96 are on a so-called

Inlet diameter arranged on which the exhaust gas flows through the outlet openings 94 and 96 and consequently from the spiral channels (floods 46 and 48) in the

Recording room streams. Fig. 3 shows respective spiral surface courses of the spiral channels present without nozzle cross-sectional area of the here in the center

symmetrical and called segment housing turbine housing, for example, the two-segment turbine with the symmetrical angular distribution 180 degrees-180 degrees. In other words, the first spiral channel (flood 46) has a flow cross-section AS1 through which the exhaust gas can flow, the course of which along the extension of the first spiral channel is illustrated by a profile 86 shown in FIG. Accordingly, the second spiral channel (flood 48) has a flow cross-section through which the exhaust gas flow AS2 whose course along the extension of the second spiral channel in Fig. 3 by a curve 88 is illustrated.

The respective extent or the respective course of the respective

Spiral channels are described using a variable φ, for example. This means that the variable φ is always related to the spiral channel

or can be, to this at any point in the circumferential direction of the receiving space or the turbine wheel 40 over its circumference

to be able to describe. With reference to the second spiral channel, the variable φ is included φ _λ . With reference to the first spiral channel, the variable φ is designated c _A GR.

It is preferably provided that the respective course of the respective

Flow cross-section AS1 or AS2 following law complies:

AS2 = AS20 x (1 -φ _Α / φ ₂ ο) ^Δ ex2 and AS1 = AS10 x (1 - ⁽ PAGR / <Ριο) ^Δ ex1.

In this case, the first spiral channel starts from a so-called inlet cross section of the first spiral channel, wherein the inlet cross section of the first spiral channel is denoted by AS10. The second spiral channel starts from an inlet cross-section of the second

Spiral channels, wherein the inlet cross-section of the second spiral channel is denoted by AS20. Based on the circumferential direction of the receiving space or the turbine wheel 40 is the inlet cross-section of the first spiral channel at the angle> i ₀ , while the inlet cross-section of the second spiral channel is at an angle φ ₂ ο. The angle φ ₂ ο is also referred to as entry angle φ _λι0 . The angle φ ₁₀ is also referred to as entrance angle cp _A GR, o.

In other words, by the above-mentioned law, a respective course, in particular spiral course, of the spiral channels for a respective

Area tap the locking body described. In this case, ex1 is a first exponent which has at least the value 2. Furthermore, ex2 is a second exponent, which

at least 2 or greater. In this case, a natural, positive number can be used as the respective exponent ex1 and ex2, the exponent ex1 and / or the exponent ex2 preferably being 2, 3, 4 or 5. Since in the present case the spiral channels are formed symmetrically to one another, the exponents are ex1 and ex2

or their values the same. In the embodiment illustrated in FIG. 3, the respective exponent is ex1 or ex2 2. The main feature is thus the same surface course with equal absolute values of the two segment spirals which flow upstream into the turbine inlet channel or the floods 34 and 36, which for example also designate manifold lines become.

By equal or unequal lengths of the locking body 90 and 92 thus a symmetrical or asymmetrical behavior of the exhaust gas lines or floods 34, 36 and thus the turbine 38 can be realized in spite of the symmetrical turbine housing. Fig. 4 shows a first embodiment of the turbine 38, wherein the locking bodies are designated 90 and 92. Furthermore, in FIG. 4, the first outlet opening of the first spiral channel designated 94 and associated with the blocking body 90 can be seen. In addition, in FIG. 4, the outlet opening of the second spiral channel assigned 96, the blocking body 92, can be seen. In the first embodiment, the locking bodies 90 and 92 are the same length and extend in each case by 90 degrees in the circumferential direction of the receiving space or the turbine wheel 40 over its circumference. As a result, a symmetrical behavior of the exhaust gas lines or the floods 34 and 36 can be realized.

FIG. 5 shows the surface course diagram of the first embodiment with FIGS

Exponent ex1 = ex2 = 2. The surface course diagram shown in FIG

takes into account the respective designated in Fig. 5 by an area 95, respectively

Nozzle cross-sectional area in the circumferential direction. Since the locking body 90 and 92 are the same length, the tongue slider is designed as a symmetrical rotary valve. Of the

Adjustment of the tongue slider is for example 70 degrees. Thus, each locking body 90 or 92 is rotatable by 70 degrees. In FIG. 4, 98 denotes a respective maximum position, with 100 a respective zero position of the respective tongue tip and 102 a respective minimum position. The maximum position 98 is an open position in which the spiral surface and the nozzle surface of about 1,100

Square millimeters in each spiral segment are tapped simultaneously. In the full closed position of 70 degrees, this area value in each segment is approximately 450 square millimeters. If the three tapping points open, zero and closed position of the two segment spirals are combined, parallel connecting lines 104 of these points are obtained in the area diagram relative to the abscissa in the case of a symmetrical tongue slider. The symmetrical tongue slider would occupy the closed position in the indicated in Fig. 4 with arrows 106 housing tongues.

For example, if the tongue slider is asymmetrical, the tongues are asymmetrical or of different lengths. The in Fig. 4

illustrated symmetrical tongue slider is referred to as 90-90 tongue slider, for example, since both locking body 90 and 92 extend over 90 degrees. In Fig. 6, the locking body 92 also extends over 90 degrees, wherein the locking body 90, for example, extends over 110 degrees. The tongue slider is thus referred to as a 90-110 tongue slider. For example, if the blocking body 92 extends over 90 degrees, while the blocking body 90 extends over 130 degrees, then the tongue slider would be referred to, for example, as a 90-130 tongue slider. Because despite this Asymmetrical tongues or the tongues of different lengths, the symmetrical turbine housing is maintained, the ends of the respective 90- 10-tongue slide and the 90-130-tongue slide (not shown) in the closed position also as in the symmetrical tongue slide directly below the housing tongue, which respectively is illustrated by the arrow 106. In order to increase the EGR rate, the symmetrical 90-90 reed shifter for an asymmetric scroll accumulation channel will now be looped 20 degrees around the EGR channel side (AGR tongue) to the slider versions 90-110 and 90-130 (not shown) modified.

In the area diagram, the tongue extension of the AGR tongue (blocking body 90) is reflected in the tapping points on the course 86, which have smaller area values than the tapping on the course 88 (not shown). The two asymmetric tongue slides thus influence the connecting lines of the simultaneous

Tongue tap, whereby the slopes of the line reflect the deviations of the AGR tongue in the area diagram (not shown). With this simple concept, a cost-effective variety of variants for influencing the engine behavior in terms of consumption and emission is possible. In order to place the exhaust gas recirculation line with the simplest means on the second cylinder group and not the first cylinder group, for example because of space problems, the concept of symmetrical segment housing with identical turbine housing and for a tongue slider advantages, since then, for example, the tongue slider shown in Fig. 6 only must be installed rotated by 180 degrees. In other words, the tongue slider is rotated only by the segment pitch angle of 180 degrees, assuming that the tongue slider dominates this new installation with the same adjustment. Since we have a symmetrical turbine housing, there is virtually no change in engine performance in terms of EGR capability, with flood 36 now being the EGR flood.

Due to the symmetrical segment spiral housing in combination with a

Symmetrical or asymmetrical tongue slider can be a simplest

Adaptability of the turbine 38 with minimal effort in terms of engine needs for EGR and λ create. Furthermore, there are the following advantages: wide range of use of the unchanged turbine main parts such as housing, wheel and adjusting device, interchanging the behavior of the first cylinder group with the second cylinder group solely by the design of the tongue slider or conversion of the tongue slider, so that no housing replacement is required and gives the advantage in that all base turbine parts as well as the tongue slide can be used; favorable Cost basis of the turbine module concept related to the wide range of applications (essentially the slide exchange); Tongue slider turbine also highly suitable for highly charged engine braking operation (turbo brake).

LIST OF REFERENCE NUMBERS

10 internal combustion engine

12 cylinder housing

14 intake tract

16 air filters

18 turbocharger

20 compressors

22 compressor wheel

24 axis of rotation

26 intercooler

28 Charge air distributor

30 exhaust tract

32 exhaust manifold

34 flood

36 flood

38 turbine

40 turbine wheel

42 rotor

44 wave

46 flood

48 flood

50 exhaust aftertreatment device

52 crankshaft

54 directional arrow

56 temperature sensor

58 exhaust gas recirculation device

60 exhaust gas recirculation line

62 valve element

64 cooling device

66 computing device

68 Motor brake device 70 double arrow

72 diagram

74 ordinates

76 abscissa

78 Constant choke

80 nozzle

82 turbine blade

84 nozzle width

86 History

88 History

90 locking body

92 locking body

94 outlet opening

95 area

96 outlet opening

98 maximum position

100 zero position

102 minimum position

104 connecting line

106 directional arrow

Claims

claims

Turbine (38) for an exhaust gas turbocharger of an internal combustion engine (10), with a turbine housing, which has a receiving space in which

Turbine wheel (40) about a rotational axis (24) relative to the turbine housing is rotatably receivable, and at least two in the circumferential direction of the receiving space extending over its circumference and by exhaust gas of the internal combustion engine (10) flow-through spiral channels (46, 48), which via respective, in

Circumferential direction of the receiving space successive outlet openings (94, 96) open into the receiving space, and with an adjusting device (70), which per outlet opening (94, 96) one about the rotation axis (24) relative to the

Turbine housing slidable locking body (90, 92), by means of which a flow-through of the exhaust flow cross-section of each

associated outlet opening (94, 96) is adjustable,

characterized in that

the spiral channels (46, 48) are symmetrical to each other and extend over the same angle of wrap, wherein the locking bodies (90, 92) have the same length extending in the circumferential direction of the receiving space or unequal lengths extending in the circumferential direction of the receiving space.

Turbine (38) according to claim 1,

characterized in that

the turbine housing exactly two spiral channels (46, 48), each having a wrap angle of 180 degrees.

3. turbine (38) according to claim 1 or 2,

characterized in that

All spiral channels (46, 48) of the turbine housing, the spiral channels (46, 48) are symmetrical to each other and the same

Extend wrapping angle.

4. Turbine (38) according to the preceding claims,

characterized in that

with unchanged position of the spiral channels (46, 48) of the housing of the turbine (38) by simple, rotational re-assembly of 180 ° of the present locking body (90, 92) about the axis of rotation (24), the uneven, in the circumferential direction of the

Lengths a change of fixation of the receiving space

Exhaust gas recirculation pipe (60) from the flood 34 to the flood 36 with almost the same accumulation characteristic results.

5. Exhaust gas turbocharger (18) for an internal combustion engine (10), with a turbine (38) according to one of the preceding claims.