DE102011115251A1 - Internal combustion engine e.g. Otto engine for passenger car, has check portions that are arranged between spiral channel outlet cross-sections downstream and turbine wheel upstream, to cause shock charge in shock loading position - Google Patents

Abstract

The engine (10) has a turbine (58) having a receiving space in turbine housings. A combustion chamber (12) is fluidly coupled with the spiral channels, for feeding exhaust gas. A positioning device is provided for adjusting the outlet cross-sections of the spiral channels. The check portions are arranged between the downstream of spiral channels outlet cross-sections and upstream of a turbine wheel, for causing a shock charge in causative shock loading position and for adjusting hold-up charge in causative jam loading position.

Description

The invention relates to an internal combustion engine for a motor vehicle specified in the preamble of claim 1. Art.

The ongoing tightening of emission limits, particularly with regard to nitrogen oxides (NO _x ) and soot emissions, also leads to a strong influence on charging devices for the supercharging of internal combustion engines of motor vehicles. The growing demands for providing a desired charge pressure due to high exhaust gas recirculation rates over the medium load range up to the full load lead to geometrically more and more downsizing turbochargers of turbochargers of the superchargers. This means that desired high turbine outputs can be realized by increasing the Aufstaufähigkeit or by reducing the absorption capacity of the turbines in interaction with the associated internal combustion engine.

Further, if necessary, the inlet pressure level of the turbines will continue to be driven up by the back pressure from downstream particulate soot filters, which entails further geometric downsizing of the turbine to meet compressor side power requirements for combustion air delivery.

In addition, there are difficulties in representing a desired exhaust gas recirculation capability in conjunction with the required combustion air of the internal combustion engine to be supplied, particularly in lower to middle operating ranges of the internal combustion engine. In the case of the usual design boundary conditions, which can also be defined from the nominal point of the internal combustion engine from the charge change side, consumption side, the lower engine speed range can not be optimally operated, in particular in the case of an asymmetric, double-flow, solid geometry turbine.

The DE 199 18 232 A1 discloses a multi-cylinder internal combustion engine with an exhaust gas turbocharger and with at least two different cylinders or cylinder groups associated, separate exhaust gas lines to the turbine of the exhaust gas turbocharger, which are fluidly connectable or separable according to the position of an actuator before entering the turbine. The actuator is connected via a control line to a control unit and receives setting commands for the demand-related separation or connection of the exhaust pipes as a function of the operating point of the internal combustion engine. It is provided that the exhaust pipes in the region of the actuator lie approximately in a plane and the actuator is formed as wall sections of the exhaust pipes carrying slide, wherein the movable wall sections in the closed position of the slide for separating the exhaust pipes in coverage with the fixed wall sections can be brought.

Furthermore, from the DE 10 2008 039 085 A1 an internal combustion engine for a motor vehicle, which comprises a turbine arranged in an exhaust tract of the internal combustion engine. The turbine has a turbine housing with a receiving space in which a turbine wheel which is rotatable about an axis of rotation is received at least in regions. The turbine housing has at least two spiral channels, which are fluidically coupled to at least one combustion chamber of the internal combustion engine, for guiding exhaust gas. The spiral channels have respective outlet cross-sections opening into the receiving space, via which the exhaust gas can be fed to the receiving space. In this case, the outlet cross-sections are arranged in the circumferential direction of the turbine wheel about its circumference next to each other, wherein the spiral channels at least a first locking body is associated with a locking device, by means of which the respective outlet cross-section of the associated spiral channel is adjustable.

The invention has for its object to further develop an internal combustion engine for a motor vehicle of the type mentioned in such a way that a more efficient operation of the internal combustion engine is made possible.

This object is achieved by an internal combustion engine for a motor vehicle having the features of patent claim 1. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the remaining claims.

Such an internal combustion engine for a motor vehicle comprises a turbine arranged in an exhaust tract of the internal combustion engine. The turbine has a turbine housing with a receiving space. In the receiving space, a turbine wheel, which can be rotated about an axis of rotation, is accommodated at least in regions. The turbine housing has at least two, each with at least one combustion chamber of the internal combustion engine fluidly coupled spiral channels for guiding exhaust gas. This means that exhaust gas from the correspondingly assigned combustion chambers can flow into the respective spiral channels.

The spiral channels have respective outlet cross-sections opening into the receiving space, via which the exhaust gas can be fed to the receiving space. This means that the respective ones Exhaust gas flowing through the spiral channels can flow out of the respective spiral channels via the respective outlet cross sections and flow into the receiving space.

The outlet cross sections are arranged side by side in the circumferential direction of the turbine wheel over its circumference. This means that a first of the outlet cross sections in the circumferential direction follows the second outlet cross section.

At least one first blocking body of an adjusting device of the turbine is assigned to each of the spiral channels. By means of the respective first blocking body of the respective outlet cross-section of the corresponding associated spiral channel is adjustable.

According to the invention, it is provided that the first blocking bodies between at least one of the spiral channels downstream of the outlet cross-sections and upstream of the turbine wheel fluidly at least substantially separated and a Stoßaufladung the internal combustion engine causing shock loading position and at least one of the spiral channels downstream of the outlet cross-sections and upstream of the turbine fluidly interconnecting and one Jam charging the internal combustion engine causing jam position are adjustable. This means that the spiral channels are fluidly separated from each other in the shock charging position, so that the internal combustion engine is particularly efficiently and effectively charged by means of shock charging.

The turbine of the internal combustion engine according to the invention thus represents a multi-flow or at least double-flow turbine with at least two floods in the form of the spiral channels, wherein the correspondingly arranged spiral channels are also referred to as spiral segments. This Mehrflutige turbine makes it possible to set a desired Aufstauverhalten to display desirable high exhaust gas recirculation rates and necessary or desirable air-fuel ratio and a desired ratio between the exhaust gas recirculation rates and the air-fuel ratio in a particularly large operating range of the internal combustion engine at least substantially optimal to be able to, with the multi-flow and segmented turbine has a particularly pronounced shock charging capability and allows the Stoßaufladung the internal combustion engine.

Turbines, which are specially designed for boost charging, have particularly large flow cross sections for the utilization of very large, usable energy fluctuations or pressure pulsations. These high pressure pulsations of the internal combustion engine exist and arise at the turbine then, if one keeps the usually adjusting throttle and friction losses on exhaust valves of the internal combustion engine and in a manifold region by a corresponding geometry design into the corresponding turbine into it.

Maintaining throttling and frictional losses upstream of the turbine promotes the achievement of a desired, extreme boost charge, thereby providing a particularly high average efficiency of exhaust exergy utilization despite large variations in turbine efficiency over time. These advantages of the supercharging can be used in the internal combustion engine according to the invention.

It has been shown that the turbine, which represents a so-called segment turbine, enables a particularly advantageous driveability in relatively highly supercharged internal combustion engines in positive internal combustion engine regions of the supercharger. This is particularly advantageous in an internal combustion engine, which is designed according to the so-called downsizing principle. Such an internal combustion engine has a relatively low displacement, but can provide particularly high torques and power.

The turbine has in addition to the described advantages due to the feasibility of the shock charging further has the advantage that by means of the turbine also very large throughput spreads can be displayed. This is particularly advantageous in a trained as gasoline engine internal combustion engine, since an Otto engine has particularly high throughput spreads. Thus, in the internal combustion engine according to the invention, for example, from a mean throughput of exhaust gas from the supercharging in the operation of the jam charging to at least substantially an entire turbine radaustrittsquerschnitt over which the turbine wheel is discharged of exhaust gas to use. In particular, it is possible by means of the adjusting devices to switch at least substantially continuously between the supercharging and the accumulating charge.

Thus, the internal combustion engine according to the invention makes it possible to combine the advantages of accumulation charging with the advantages of supercharging, which leads to particularly efficient operation of the internal combustion engine in at least almost its entire characteristic field. As a result, the internal combustion engine can be operated with only low fuel consumption, which is associated with low CO ₂ emissions.

Another advantage of the internal combustion engine according to the invention is that the fluidic separation or merging of the individual spiral channels at least almost immediately upstream takes place of the turbine wheel. In other words, the exhaust gas is fed into the receiving space in particularly close proximity to the turbine wheel. This leads to a particularly advantageous flow of the turbine wheel from the exhaust gas. In addition, a particularly efficient supercharging of the internal combustion engine is thereby represented in the Stoßaufladestellung what their efficient operation benefits.

In addition, the adjusting device advantageously provides the functionality of being able to variably set the outlet cross-sections, which are also referred to as flow nozzle surfaces, directly in front of the turbine wheel by means of the blocking bodies. In other words, it is possible to increase the outlet cross-sections by moving the locking body relative to the turbine housing and to reduce it in contrast. Thus, the outlet cross sections and thus the turbine can be adapted to a variety of different operating points as well as to a variety of different exhaust gas mass flows of the internal combustion engine efficiently and as needed.

The for the accumulation of the exhaust gas (Strömungsaufstau) co-determining turbine outlet cross section downstream of the turbine, which can temporarily only use portions of the Gesamtturbinenradaustrittsquerschnitts for the incoming pressure pulses in the shock charging operation is also temporary then at least almost completely by the continuous switching or the continuous transition from Stoßaufladebetrieb to accumulation charging operation permeable, whereby the degree of utilization of the turbine wheel outlet cross-section over such an average of the accumulation of charge via the adjusting device upstream of the turbine wheel quasi its full value of at least almost 100% receives.

Thus, not only a so-called Radeintrittsvariabilität is created by the adjusting device upstream of the turbine wheel. Rather, an effective, continuous turbine wheel outlet cross-section variability of the averaging out of the segments via the charge accumulation or pulsation smoothing caused in the turbine wheel inlet region is also achieved in the case of the solid geometry turbine wheel that can not be adjusted geometrically, for example.

In an advantageous embodiment of the invention, a first of the spiral channels with a plurality of first combustion chambers, that is, with at least two first combustion chambers of the internal combustion engine fluidly connected. Thus, exhaust gas from the plurality of first combustion chambers in the first spiral channel and flow through this. The second spiral channel is fluidly connected exclusively to a single second combustion chamber of the internal combustion engine. This means that the first spiral channel is not fluidically connected to the second combustion chamber. It follows that only the exhaust gas from the second combustion chamber in the second spiral channel and this can flow through, while the exhaust gas from the first combustion chambers only in the first spiral channel and this can flow through. As a result, particularly high exhaust gas recirculation rates can be represented. This means that particularly high amounts of exhaust gas can be recirculated from the exhaust gas tract to an intake tract of the internal combustion engine and introduced into the intake tract. The exhaust gas can act as an inert gas in the combustion processes occurring in the combustion chambers and thereby keep the formation of nitrogen oxides (NO _x ) in a very small frame.

In a further advantageous embodiment, the first blocking body between the Stoßaufladestellung and the Staufaufladestellung in the circumferential direction of the turbine wheel over the circumference of the axis of rotation are displaceable. This displaceability in the circumferential direction over the axis of rotation of the turbine wheel represents a very advantageous type of movement of the adjusting device or the first locking body, which keeps the space requirement of the turbine particularly low. This is particularly advantageous in a space-critical area, such as in an engine compartment of the motor vehicle designed, for example, as a passenger car. This can solve and / or avoid package issues.

Alternatively or additionally, it is also possible to provide an axial adjustability of the adjusting device or of the first blocking body. This means that the first blocking bodies can additionally or alternatively also be displaceable at least substantially in the axial direction of the turbine wheel. As a result, a further degree of freedom is created by means of which a particularly high variability and varied adjustability of the adjusting device can be realized.

The first blocking body may be at least substantially tongue-shaped or wing-shaped. The adjusting device is thus designed as a so-called tongue slider whose locking body (tongues) can be displaced in the circumferential direction over the circumference of the turbine wheel about the axis of rotation. The blocking bodies (tongues) are displaced in an annular channel which extends in the circumferential direction of the turbine wheel over its circumference. The fluidic connection of the spiral channels in the accumulation charging position of the blocking body takes place in the annular channel and thus at least almost immediately upstream of the turbine wheel, which benefits its flow from the exhaust gas.

In addition, the tongue slider has a particularly low complexity. This benefits his robustness. This means that the tongue slider can ensure a high functional performance safety even over a long service life and at high exhaust gas temperatures.

In a further advantageous embodiment, the first combustion chambers are fluidically brought together by means of at least one exhaust gas piping element, in particular an exhaust manifold, of the exhaust gas tract, wherein an exhaust gas recirculation device is provided. The exhaust gas recirculation device comprises at least one exhaust gas recirculation line which is fluidically connected at one end to the intake tract of the internal combustion engine at a point of introduction and at the other end at a branching point to the exhaust gas piping element. As a result, exhaust gas can be branched off at the branching point, be recirculated from the exhaust tract to the intake tract and introduced into the intake tract at the point of introduction. By merging the first combustion chambers are particularly high exhaust gas recirculation rates, d. H. particularly high amounts of recirculating exhaust gas can be displayed. In particular, the nitrogen oxide and particle emissions of the internal combustion engine can be kept low.

In an advantageous embodiment of the invention, the first blocking bodies are each assigned at least one second blocking body, which adjoins the associated first blocking body in the axial direction. In other words, in each case at least one second blocking body follows on the first blocking body. It is provided that the first locking body and the second locking body differ from each other in terms of their extent in the circumferential direction of the turbine wheel over its circumference. The adjusting device is adjustable in the axial direction of the turbine wheel between a first position in which the outlet cross sections are adjustable by means of the first locking body, and at least one second position in which the outlet cross sections are adjustable by means of the second locking body. This means that in the first position, the outlet cross-sections of the spiral channels by moving the first locking body in the circumferential direction are variably adjustable. In the second position, the outlet cross sections can be variably adjusted by displacing the second blocking body in the circumferential direction about the axis of rotation of the turbine wheel. For adjusting the adjusting device between the first position and the second position, the locking body are axially displaceable. Characterized a particularly high variability of the adjusting device is shown, wherein the first locking body (first tongues) and the second locking body (second tongues) are formed differently in size.

For example, the first locking body are formed smaller than the second locking body and thus allow a relatively large flow passage or outlet cross-sections of the spiral channels. The second blocking bodies are designed to be larger than the first blocking bodies and accordingly permit a flow passage or exit cross-sections of the spiral channels which is smaller in comparison. As a result, a series connection of differently sized blocking body (tongues) is shown. As a result, the turbine of the internal combustion engine according to the invention can be adapted particularly variably and as needed to different operating points of the internal combustion engine. This benefits the efficient and fuel-efficient operation of the internal combustion engine according to the invention.

In a further advantageous embodiment, the turbine wheel has at least one impeller blade with a wheel edge, the wheel edge having a first longitudinal region extending at least substantially in the axial direction, a second longitudinal region adjoining the first longitudinal region and a third longitudinal region adjoining the second longitudinal region having. In this case, the second length range and the first length range include an angle different from 180 °. Similarly, the second length range and the third length range include an angle different from 180 ° with each other. It is preferably provided that the third longitudinal region extends at least substantially in the radial direction of the turbine wheel. By virtue of this embodiment, particularly advantageous flow conditions are created so that the exhaust gas can flow and flow off the turbine wheel in a particularly efficient manner.

Preferably, an inflow edge is formed by means of at least a portion of the first length region, via which the turbine wheel of the exhaust gas, in particular in the radial direction can be flowed. Furthermore, by means of the second length region and the third longitudinal region, respective outflow edges are preferably formed, via which the turbine wheel can be flowed off the exhaust gas. As a result, particularly advantageous flow conditions are created.

In a further advantageous embodiment of the invention, a further adjusting device is arranged in a turbine wheel outlet region, ie downstream of the turbine wheel, by means of which the turbine wheel outlet cross section is variably adjustable. In this case, the further adjusting device constitutes a wheel outlet variability that is separate from the adjusting device. The turbine of the invention can be produced by means of the wheel inlet variability represented by the adjusting device and the wheel outlet variability represented by the further adjusting device Internal combustion engine particularly efficient, needs-based and flexible adapted to different operating points of the internal combustion engine.

By means of the further adjusting device, it is thus possible to variably set the so-called effective turbine outlet cross section in the accumulation charging mode as well as in the shock charging mode with respect to its flow area, so that the exhaust gas can use a variably adjustable flow area for the outflow of the turbine wheel.

Advantageously, the further adjusting device for adjusting the turbine wheel outlet cross-section in the axial direction is displaceable. As a result, the turbine wheel outlet cross section can be set efficiently and as needed. In addition, the adjusting device thus has a particularly low complexity, which is associated with a high degree of robustness and thus with a very high functional performance reliability.

In a further advantageous embodiment, at least one of the first blocking body and / or at least one of the second blocking body extends in the circumferential direction of the turbine wheel over its circumference over a wrap angle, wherein the wrap angle is in a range of from 35 ° to 55 ° inclusive. On the one hand, the outlet cross sections of the spiral channels can thereby be advantageously set, which benefits the advantageous adaptability of the turbine to different operating points of the internal combustion engine. On the other hand, the spiral channels can thereby be advantageously fluidly connected to one another to represent the accumulation charging operation, so that a particularly efficient accumulation charging operation can also be carried out.

To illustrate the accumulation charging operation, it is provided, for example, that the first or possibly the second blocking bodies are moved into the respective outlet cross sections of the spiral channels so far that interaction of the blocking bodies with walls delimiting the spiral channels, whereby the spiral channels are fluidically separated from each other, is canceled.

The internal combustion engine according to the invention also has the advantage that particularly high throughput spreads are possible by the adjustability of the adjusting device, wherein a Umblaseeinrichtung, by means of which the turbine of exhaust gas to bypass and so is not driven, can be omitted or is not provided. Such a blow-off device, which is also referred to as a bypass device, leads if no appropriate countermeasures are taken - to undesirably high losses, since the exhaust gas surrounding the turbine is energetically not used. In the internal combustion engine according to the invention such a blow-off device (bypass device) is not required and not provided, which keeps the losses and thus the energy required to operate the internal combustion engine low. At the same time, high throughput spreads are also possible.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments 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 in the figures alone can be used not only in the respectively indicated combination but also in other combinations or in isolation, without the scope of To leave invention.

The drawing shows in:

1 a schematic diagram of an internal combustion engine for a motor vehicle, with an exhaust gas turbocharger comprising a turbine with a turbine housing;

2a a schematic side view of an embodiment of a turbine housing of the turbine according to 1 ;

2 B a schematic front view of the turbine housing according to 2a ;

2c a further schematic side view of the turbine housing according to the 2a -b;

3 a schematic diagram of another embodiment of the internal combustion engine according to 1 ;

4 a schematic cross-sectional view of a further embodiment of the turbine according to the 1 to 3 ;

5 a schematic plan view of a trained as a tongue slide actuator, which in a turbine wheel inlet region of a turbine wheel of the turbine according to the 1 to 4 to arrange;

6 one with the adjusting device according to 5 Corresponding representation of Spiralflächenverläufen and Ringdüsenflächenverläufen at an adjustment of the adjusting device;

7 a schematic plan view of another embodiment of the adjusting device according to 6 ;

8th one with the adjusting device according to 7 Corresponding representation of Spiralflächenverläufe and Ringdüsenflächenverläufen in an adjustment of the adjusting device according to 7 ;

9 a schematic plan view of another embodiment of the adjusting device according to the 5 and 7 ;

10 one with the adjusting device according to 9 Corresponding representation of Spiralenflächenverläufen and Ringdüsenflächenverläufen in an adjustment of the adjusting device according to 9 ;

11 a schematic longitudinal sectional view of a turbine wheel of the turbine according to the 1 to 10 ;

12 a schematic longitudinal sectional view of another embodiment of the turbine according to 11 ;

13 a schematic plan view of an embodiment of the turbine according to the 11 and 12 ;

14 a schematic longitudinal sectional view of the turbine according to 13 ;

15 a schematic plan view of the turbine according to the 13 and 14 ;

16 a further schematic view of the turbine according to the 13 to 15 ;

17 a schematic perspective view of the turbine according to the 13 to 16 ; and

18 a diagram with two curves of annular nozzle cross sections in the adjustment of an actuator of the turbine according to 1

The 1 shows an internal combustion engine 10 for a motor vehicle, such as a commercial vehicle or a passenger car. The internal combustion engine 10 is designed as a reciprocating internal combustion engine and comprises six cylinders 12 in which during a fired operation of the internal combustion engine 10 Burns occur. In the cylinders 12 a respective piston is translational relative to the associated cylinder 12 movably received. These pistons are connected via respective connecting rods with a crankshaft rotatable about a rotation axis 14 the internal combustion engine 10 articulated coupled. About the articulated coupling of the pistons with the crankshaft 14 can the translational movements of the pistons in the cylinders 12 in a rotational movement of the crankshaft 14 to be converted, which is in the 1 by a directional arrow 16 is indicated.

During operation of the internal combustion engine 10 sucks in this air, which in an intake 18 the internal combustion engine 10 and flows through it. First, the sucked air by means of a in the intake 18 arranged air filter 20 cleaned. Subsequently, the air is through a in the intake 18 arranged compressor 22 an exhaust gas turbocharger 24 the internal combustion engine 10 compressed and thereby heated.

In the intake tract 18 is downstream of the compressor 22 a charge air cooler 26 arranged, which cools the compressed and thereby heated air. In addition, in the intake tract 18 a charge air distributor 28 arranged, which the compressed and by means of the intercooler 26 cooled air on the cylinders 12 distributed.

From the combustion processes in the cylinders 12 emerging exhaust gas flows in exhaust piping 30 an exhaust tract 32 the internal combustion engine 10 one. The exhaust piping 30 include an exhaust manifold 34 , which with three first of the cylinders 12 is fluidically connected and the exhaust gas of the first of the cylinder 12 collects and leads to a first flood 36 merges. With the first flood 36 is an exhaust gas recirculation line 38 an exhaust gas recirculation device 40 at a branch point 42 fluidly connected. The exhaust gas recirculation line 38 is at a discharge point 44 fluidic with the intake tract 18 connected. About the exhaust gas recirculation line 38 can the exhaust gas recirculation device 40 Exhaust gas at the branch point 42 from the exhaust tract 32 branch off to the intake tract 18 return and at the discharge point 44 in the intake tract 18 initiate.

To set a desired amount of exhaust gas to be recirculated, the exhaust gas recirculation device comprises 40 an exhaust gas recirculation valve 46 which at least partially in the exhaust gas recirculation line 38 is arranged. In the flow direction of the recirculated exhaust gas downstream of the exhaust gas recirculation valve 46 and upstream of the discharge point 44 is an exhaust gas recirculation cooler 48 arranged, by means of which the recirculated exhaust gas is to be cooled.

From this it is evident that the first tide 36 is used in particular to represent a desired high Aufstauverhalten to particularly high amounts of exhaust gas to the intake 18 recirculate. Therefore, the first tide 36 also referred to as EGR flood (EGR exhaust gas recirculation).

The exhaust piping 30 also form a second tide 50 a third flood 52 and a fourth flood 54 , each with a second of the cylinder 12 are fluidically connected. Thus, the second tide 50 only from exhaust from a second of the cylinders 12 flows through. Likewise, the floods 52 . 54 in each case only of exhaust gas from a second of the cylinders 12 flows through. The floods 50 . 52 . 54 are used in particular to set a desired air-fuel ratio, which is also referred to from combustion air ratio λ, so as to set a desired torque and a desired power of the internal combustion engine 10 to realize. Therefore, the floods 50 . 52 . 54 also called λ-floods.

In the exhaust tract 32 is also a turbine 56 the exhaust gas turbocharger 24 arranged. The turbine 56 includes a turbine wheel 58 that of exhaust from the cylinders 12 is drivable. The turbine wheel 58 is about a rotation axis 60 rotatable and with a shaft 62 the exhaust gas turbocharger 24 rotatably connected, so that the turbine wheel 58 with the wave 62 around the axis of rotation 60 can turn. With the wave 62 is also a compressor wheel 64 of the compressor 22 rotatably connected, so that the turbine wheel 58 due to the application of the exhaust gas via the shaft 62 the compressor wheel 64 can drive. This is by a directional arrow 66 shown.

After driving the turbine wheel 58 the exhaust gas flows further through the exhaust tract 32 to a downstream of the turbine wheel 58 arranged exhaust aftertreatment device 68 by which the exhaust gas is purified before it is released to the environment.

As in synopsis with the rest 2a to 17 can be seen, includes the turbine 56 a turbine housing 70 which is a recording room 72 having. In the recording room 72 is the turbine wheel 58 at least partially around the axis of rotation 60 relative to the turbine housing 70 rotatably received.

The turbine housing 70 also has a first spiral channel 74 on, which has a flange 76 of the turbine housing 70 with the first flood 36 (EGR flood) to be fluidly connected. This allows the exhaust gas from the first flood 36 in the first spiral channel 74 flow. Therefore, the first spiral channel becomes 74 also referred to as EGR spiral channel.

In addition, the turbine housing points 70 a second spiral channel 78 , a third spiral channel 80 and a fourth spiral channel 82 on. About the flange 76 becomes the second spiral channel 78 fluidly with the second tide 50 connected. The third spiral channel 80 is over the flange 76 with the third flood 52 connected while the fourth spiral channel 82 over the flange 76 with the fourth tide 54 is connected. Thus, the spiral channels become 78 . 80 . 82 referred to as λ-spiral channels.

The spiral channels 74 . 78 . 80 . 82 have respective outlet cross sections 84 on, which are also referred to as spiral surfaces or spiral cross-sections. About the outlet cross sections 84 Can this be the spiral channels 74 . 78 . 80 . 82 flowing exhaust gas into the receiving space 72 one and the turbine wheel 58 Provide flow. In the 4 In this case, a maximum EGR spiral cross-section A _{AGR, 0 is} shown, which of immovable, the first spiral channel 74 delimiting walls of the turbine housing 70 is limited.

In addition, in the 4 respective maximum λ-spiral cross-sections A _{λ, 0} shown, which of the spiral channels 78 . 80 . 82 limited walls of the turbine housing 70 are limited and which are smaller than the maximum EGR spiral cross-section A _{AGR, 0} .

Again 5 it can also be seen, are the outlet cross-sections 84 in the circumferential direction of the turbine wheel 58 over its circumference consecutively, ie arranged side by side. The individual spiral channels 74 . 78 . 80 . 82 thus represent segments over which the turbine wheel 58 in segments of the exhaust gas is to be applied. The first spiral channel 74 represents a so-called EGR segment, while the spiral channels 78 . 80 . 82 represent so-called λ segments.

The turbine 56 includes a first actuator 86 with blocking bodies in the form of wing-shaped tongues 88 , which in the circumferential direction of the turbine wheel 58 about its circumference about the axis of rotation 60 are displaceable. Here are the spiral channels 74 . 78 . 80 . 82 one each of the tongues 88 assigned.

The tongues 88 are between at least one of the spiral channels 74 . 78 . 80 . 82 downstream of the outlet cross sections 84 and upstream of the turbine wheel 58 fluidly at least substantially separated from each other, a Stoßaufladung the internal combustion engine 10 effecting and in the 4 illustrated Stoßaufladestellung and at least one of the spiral channels 74 . 78 . 80 . 82 downstream of the outlet cross sections 84 and upstream of the turbine wheel 58 fluidly interconnecting and a congestion charging the internal combustion engine 10 causing accumulation charging position adjustable. in the jam charging position for effecting the jam charging are the tongues 88 each so far in each nozzle cross-sections 90 the spiral channels 74 . 78 . 80 . 82 turned that they are no longer with the the spiral channels 74 . 78 . 80 . 82 bounding walls for fluidically separating the spiral channels 74 . 78 . 80 . 82 interact, but the fluidic connection of the spiral channels 74 . 79 . 80 . 82 allow or effect.

The tongues 88 are doing, for example, with a about the axis of rotation 60 rotatable ring connected so that by turning one ring the tongues 88 at the same time around the axis of rotation 60 can be moved. The ring and thus the tongues 88 are in an adjustment range Δφ, in particular in an angular range, about the axis of rotation 60 rotatable. In the 4 In this case, φ denotes a running variable which is the rotational position or the angular position or the displacement angle of the tongues 88 around the axis of rotation 60 characterized. The value 0 ° for φ is a starting position of the tongues 88 , Overall, the tongues 88 adjustable by absolutely 60 °, which is expressed by Δφ = 60 °. In other words, the running variable φ denotes the attitude angle of the tongues 88 , Starting from the initial position at φ = 0 °, the accumulation of charge is effected when -15 ° ≤ φ ≤ 0 ° and is set, ie when the tongues 88 are set in their initial position or in the negative region of the adjustment range marked with a minus sign.

For example, if φ is 0 °, the tongues 88 are in the starting position, so there is a full flow around the wing-shaped tongues 88 in the nozzle cross sections 90 instead, with the separation of the segments upstream of the turbine wheel 58 at least largely canceled and at least almost reaches the limit position of congestion charging. You turn the tongues 88 starting from the initial position such that φ is in a range of 0 ° <φ ≤ 30 °, so are the spiral channels 74 . 78 . 80 . 82 open to congestion charge, while in a range in which 30 ° <φ ≤ 45 °, results in a closing. It can be seen that the adjustment range Δφ of -15 ° to 45 ° and thus absolute 60 °. In the 4 is marked with a plus sign a positive range of the adjustment Δφ.

According to 4 are the tongues 88 while in a rotational position, in which φ is 30 °. Again 4 it can also be seen that φ refers to a positive direction of rotation of the tongues 88 rear edge 92 the tongues 88 , The tongues 88 represent a profiled blading.

In the 4 is also by broken lines an annular channel 94 hinted, in soft tongues 88 around the axis of rotation 60 be moved. The fluidic separation for the representation of the shock charge and the fluidic connection for the representation of the charge accumulation takes place at least substantially in the annular channel 94 almost immediately upstream of the turbine wheel 58 ,

In the 5 Furthermore, another variable is shown, which is the so-called segment angle of the spiral channels 74 . 78 . 80 . 82 (Segments). The segment angle refers to the extension of the nozzle cross sections 90 in the circumferential direction of the turbine wheel 58 over its circumference and thus can also be referred to as spiral angle. A base segment angle ε _{0 of} the spiral channels, also referred to as spiral base angle 74 . 78 . 80 . 82 ie when the tongues 88 not in the nozzle cross sections 90 protrude, is in each case 90 °.

Rise the tongues 88 in the respective nozzle cross sections 90 into it, so are the outlet cross sections 84 (Spiral cross sections) no longer exclusively through the spiral channels 74 . 78 . 80 . 82 limiting walls, but on the one hand by one of the walls and on the other hand by the respective tongues 88 limited, ie tapped. In addition, by moving the tongues 88 the nozzle cross sections 90 be set variably.

As based on the 13 to 17 is apparent in the bumping with respect to the circumferential direction of the turbine wheel 58 over its circumference, a quarter-segment pulsation of the turbine wheel 58 over the present four spiral channels 74 . 78 . 80 . 82 (Segments). This quarter-segment pulsation impingement in the surge charging operation takes place in that both the λ segments and the EGR segment represent respective, with respect to the circumferential direction of the turbine wheel over its circumference of quarter segments, via which the exhaust gas to the turbine wheel 58 is supplied.

When transitioning from the bumping charge to congestion charging by adjusting the tongues 88 , which are also referred to as a tongue slider together with the ring, in the averaging a full application of the turbine wheel 58 take place in the circumferential direction over its circumference.

The same applies to a turbine wheel outlet cross-section A2, via which the turbine wheel 58 is discharged from the exhaust gas. When switching the mode or mode of operation of the shock to accumulate charging, it is also possible to complete the Turbinenradaustrittsquerschnitt A2 from a segment sub-application for at least substantially full application, which means a high degree of utilization of the turbine wheel outlet A2.

However, certain designs may require a further enlargement, in particular a now geometric cross-sectional enlargement of the turbine wheel outlet cross section A2, to be performed in order to maximize the flow through the turbine 56 with desired high efficiencies, so allow low leakage losses.

The 3 shows a possibility for realizing such a geometric cross-sectional enlargement. The turbine 56 according to 3 includes a second actuator 96 which is at least substantially displaceable in the axial direction. By the second adjusting device 96 is a wheel outlet variability downstream of the turbine wheel 58 created, by which the turbine wheel outlet cross section A2 can be set variably, that can be increased or decreased. This is the turbine 56 designed as a full-variate turbine, both by the adjusting device 86 formed wheel inlet variability and the wheel outlet variability. The second adjusting device 96 For example, a contour element arranged in the turbine wheel outlet region, in particular a contour cone, comprises by means of which flow edges 98 ( 11 ) respective vanes 99 of the turbine wheel 58 at least in a partial area can be covered and released.

Turning, for example, starting from the rotational position of the tongues 88 according to 4 , causing the shock charge, the tongues 88 in the picture plane the 4 clockwise, that's how the tongues get 88 in a free nozzle area of the spiral channels 74 . 78 . 80 . 82 or the nozzle cross sections 90 so that the fluidic isolation or obstruction of the four segments upstream of the turbine wheel 58 lifted and the bump charge is effected.

The 1 and 3 can also be seen a control device 97 , by means of which the internal combustion engine 10 as well as the adjusting device 86 and optionally the further adjusting device 96 to be regulated or controlled.

The 5 . 7 and 9 show a respective embodiment of the tongue slider with the tongues 88 , which are in their respective length or in their respective angle of wrap in the circumferential direction of the turbine wheel 58 different from each other across its scope. The tongues 88 of the tongue slider according to 5 have a wrap angle of at least substantially 35 °, while the tongues 88 of the tongue slider according to 7 a wrapping angle, which is also referred to as wrap angle, of at least substantially 45 °. The tongues 88 of the tongue slider according to 9 have a wrap angle of at least substantially 55 °.

The 6 shows one with the tongue slider according to 5 corresponding diagram 100 while the 8th one with the tongue slider according to 7 corresponding diagram 100 shows. Accordingly, the shows 10 one with the tongue slider according to 9 corresponding diagram 100 , In the diagrams 100 are each a first course 102 , a second course 104 , a third course 106 and a fourth course 108 entered. On the abscissa 109 the diagrams 100 is the spiral angle (running variable ε) plotted while on the ordinate 110 a surface measure is plotted. This characterizes the first course 102 the behavior of the spiral cross sections of the. λ segments in the adjustment of the tongue slider in its adjustment over Δφ = 60 ° away. Accordingly, the second course characterizes 104 the behavior of the spiral cross-section of the EGR segment. The third course 106 characterizes the behavior of the nozzle cross sections 90 the λ segments when adjusting the tongue slider, during the fourth course 108 the behavior of the nozzle cross-section 90 characterized in terms of its cross-sectional area of the EGR segment and the AGR spiral.

Like the diagrams 100 can be seen, is achieved at an upper Verstellwinkelbereich or adjustment Δφ of 60 ° of the tongue slider of the spiral cross section of a first value (output value) to the maximum spiral cross section A _{AGR, 0} or A _{λ, 0} at an adjustment angle φ. For example, in the λ segments, the first value is 560 mm ² , while the first value in the EGR segment is 210 mm ² , for example. The maximum EGR spiral cross section A _{AGR, 0 of} the EGR spiral is, for example 560 mm ² , while the maximum λ spiral cross section A _{λ, 0 of} the λ segments, for example, 1500 mm ² in a tongue slide according to 5 is. The remaining adjustment range of Δφ of 25 ° thereby influences the degree of congestion charging by the position of the blade profiles representing tongues 88 to the immovable, the spiral channels 74 . 78 . 80 . 82 delimiting walls of the turbine housing 70 ,

The tongue slider according to 7 and according to 9 grip in the so-called 0-position, that is at a maximum φ or minimum cross-sections substantially small spiral cross-sections or spiral cross-sectional areas. Thus, the initial value of the λ segments of the tongue slider is according to 7 376 mm ² , while the output value of the AGR segment of the tongue slider according to 7 140 mm ² . The output value of the λ segments of the tongue slider according to 9 is 233 mm ² , while the output value of the AGR segment of the tongue slider according to 9 89 mm ² . The maximum spiral cross sections A _{AGR, 0} and A _{λ, 0} are in the tongue slides according to the 5 . 7 and 9 equal. So very high throughput spread ratios can be effected up to 6.5. The spread of the spiral surfaces or the spiral cross sections, which by means of the tongue slider according to 5 can be represented, ie the ratio of a maximum spiral surface or the maximum spiral cross-section As, max to a minimum spiral surface or the minimum Spiral cross-section As, min is 2.68. Accordingly, the means of the tongue slider according to 7 representable spreading 3.99, while the means of the tongue slider according to 9 representable spread is 6.44.

By simply replacing the tongue slider, a noticeable change in turbine behavior can be produced, with both burst charging and accumulation charging feasible. With this relatively simple measure optimal adjustments of turbines can be made by exhaust gas turbochargers to associated internal combustion engines of different performance, whereby the equipment of performance variants of the internal combustion engines with the same base turbine and accordingly adapted tongue slides can be done very cheaply.

The 11 to 18 illustrate embodiments of the turbine wheel 58 , The 18 shows another diagram 112 , on whose further abscissa 114 the ε and on its further ordinate 116 a surface measure is plotted. From the further diagram 112 can be determined for a selected Turbinenradaustrittsquerschnitt A2 the at least almost optimal position of the tongue slider with an at least almost optimal degree of reaction in the range of 0.5 for the Stoßaufladebetrieb as well as for the Staufaufladebetrieb. The 11 shows an embodiment of the turbine wheel 58 , in which the Turbinenradaustrittsquerschnitt A2 has a value of 1809 mm ² , which in the Stauaufladebetrieb, ie with temporary Vollbeaufschlagung, a maximum efficiency nozzle cross-section upstream of the turbine wheel 58 of about A_Düse = 1/2 × A2 = 905 mm ² requires.

Again 11 can be seen, the flow edge 98 the paddle wheel 99 a first length range 118 , an adjoining second length range 120 and an adjoining third length range 122 on. This closes the second length range 120 with the first length range 118 and with the third length range 122 a respective angle, which is smaller than 180 °. The paddle wheel 99 is doing in a partial area of the first length range 118 Exhaust gas flowed, so the first length range 118 Also referred to as the leading edge. The paddle wheel 99 is about the length ranges 120 . 122 from the exhaust gas flow, so the length ranges 120 . 122 also be referred to as trailing edges.

In the diagram 112 is a first area of congestion charging operation with 134 while a second area of the surge charging operation with 136 is designated. In the further diagram 112 are a fifth course 124 and a sixth course 126 entered. The fifth course 124 characterizes the nozzle cross sections 90 the λ segments with respect to their respective areas or areas. Accordingly, the sixth course characterizes 126 the nozzle cross-section 90 of the AGR segment in terms of its area or area. Further, in the further diagram 112 a first position 128 , a second position 130 and a third position 132 entered the tongue slider, the first position 128 an ε of 18 °, the second position 130 an ε of 31 ° and the third position 132 corresponds to an ε of 55 °. At the first position 128 (ε = 18 °) would be set at obstructed EGR segment, the at least substantially optimal nozzle cross section 90 ° of A_Düse the λ segments in combination with the turbine wheel outlet cross section A2. In the real case, however, is the sum of the nozzle cross-sections in the Stauaufladebetrieb 90 , which are also referred to as nozzle segments, the AGR and the λ segments prevailing, which is why the optimal efficiency position of the tongue slider is set at about ε = 28 to 29 °.

In the shock charging mode, on the other hand, apart from the nozzle segments in the absolute system, the complete separation of the segments of the turbine wheel also results 58 in the rotating relative system, which is why each nozzle segment faces only ¼ of the turbine wheel outlet cross section A2. In the present example, for each segment, with an optimum degree of reaction of 0.5, the following applies: A_Segment = A2_Segment / 2 = A2 / (2 × 4).

As with the other diagram 112 can be seen, thus results in the shock charging operation in the λ segments in the third position of the tongue slider for the nozzle segments of the λ segments at ε = 55 ° and the nozzle segment of the EGR segment in the second position of the tongue slider at ε = 31 ° the optimum efficiency position of the segments of the turbine 56 ,

In other words, the optimal nozzle cross-section results in the congestion charging operation 90 from A_ nozzle to the half of the turbine wheel outlet section A2. When Stoßaufladebetrieb results in the optimal nozzle cross-section 90 from A_ nozzle to the half of the turbine exit section A2 divided by the number of segments (here four).

The 12 shows an alternative embodiment of the turbine wheel 58 , whose turbine wheel outlet A2 is 1520 mm ² . At the turbine wheels 58 These are radial turbine wheels, with the turbine wheel 58 according to 11 a roller wheel and the according to 12 a contoured radial turbine wheel with respect to the Turbinenradaustrittsquerschnitt A2 of the turbine wheel 58 according to 11 reduced Radaustrittsfläche (Turbinenradaustrittsquerschnitt A2) is.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 19918232 A1 [0005]
• DE 102008039085 A1 [0006]

Claims (10)

Internal combustion engine ( 10 ) for a motor vehicle, with one in an exhaust tract ( 32 ) of the internal combustion engine ( 10 ) arranged turbine ( 58 ) with a receiving space ( 72 ) turbine housing ( 70 ), in its reception room ( 72 ) about a rotation axis ( 60 ) rotatable turbine wheel ( 58 ) is received at least in some areas and the at least two, each with at least one combustion chamber ( 12 ) of the internal combustion engine ( 10 ) fluidically coupled spiral channels ( 74 . 76 . 78 . 80 . 82 ) for carrying exhaust gas, the respective in the receiving space ( 72 ) outlet cross sections ( 84 ) about which the receiving space ( 72 ) the exhaust gas is supplied, in the circumferential direction of the turbine wheel ( 58 ) are arranged side by side over its circumference, wherein the spiral channels ( 74 . 76 . 78 . 80 . 82 ) in each case at least one first blocking body ( 88 ) an actuating device ( 86 ) is assigned, by means of which the respective outlet cross-section ( 84 ) of the assigned spiral channel ( 74 . 76 . 78 . 80 . 82 ), characterized in that the first blocking bodies ( 88 ) between at least one of the spiral channels ( 74 . 76 . 78 . 80 . 82 ) downstream of the outlet cross sections ( 84 ) and upstream of the turbine wheel ( 58 ) fluidly at least substantially separated from each other and a supercharging of the internal combustion engine ( 10 ) causing impact charging position and at least one of the spiral channels ( 74 . 76 . 78 . 80 . 82 ) downstream of the outlet cross sections ( 84 ) and upstream of the turbine wheel ( 58 ) fluidly interconnecting and a Staufaufladung the internal combustion engine ( 10 ) causing accumulation charging position are adjustable. Internal combustion engine ( 10 ) according to claim 1, characterized in that a first of the spiral channels ( 74 . 76 . 78 . 80 . 82 ) with a plurality of first combustion chambers ( 12 ) of the internal combustion engine ( 10 ) and the second spiral channel ( 74 . 76 . 78 . 80 . 82 ) exclusively with a single second combustion chamber ( 12 ) of the internal combustion engine ( 10 ) is fluidly connected. Internal combustion engine ( 10 ) according to one of claims 1 or 2, characterized in that the first combustion chambers ( 12 ) by means of at least one exhaust gas piping element ( 34 ) of the exhaust tract ( 32 ) are fluidically combined, wherein an exhaust gas recirculation device ( 40 ) is provided, the exhaust gas recirculation line ( 38 ) fluidly with the exhaust piping ( 30 ) connected is. Internal combustion engine ( 10 ) according to one of the preceding claims, characterized in that the first blocking bodies ( 88 between the shock charging position and the accumulation charging position in the circumferential direction of the turbine wheel (FIG. 58 ) about its circumference about the axis of rotation ( 60 ) and / or in the axial direction of the turbine wheel ( 58 ) are displaceable. Internal combustion engine ( 10 ) according to one of the preceding claims, characterized in that the first blocking bodies ( 88 ) in each case at least one second locking body is assigned, which in the axial direction of the associated first locking body ( 88 ), wherein the first blocking bodies ( 88 ) and the second locking bodies with respect to their extent in the circumferential direction of the turbine wheel ( 58 ) differ from one another over its circumference and wherein the adjusting device ( 86 ) in the axial direction of the turbine wheel ( 58 ) between a first position, in which the outlet cross sections ( 84 ) by means of the first blocking body ( 88 ) are adjustable, and a second position in which the outlet cross-sections ( 84 ) are adjustable by means of the second locking body, is adjustable. Internal combustion engine ( 10 ) according to one of the preceding claims, characterized in that the turbine wheel ( 58 ) at least one impeller blade ( 99 ) with a wheel edge ( 98 ), wherein the wheel edge ( 98 ) has a first length region extending at least substantially in the axial direction ( 118 ), to the first length range ( 118 ) and with the first length range ( 118 ) includes a second longitudinal region (180) different first angle ( 120 ) and a to the second length range ( 120 ) and with the second length range ( 120 ) includes a third length range including 180 degrees different second angle ( 122 ). Internal combustion engine ( 10 ) according to claim 6, characterized in that by means of at least a portion of the first length range ( 118 ) a leading edge is formed, over which the turbine wheel ( 58 ) is flowed by the exhaust gas, wherein by means of the second length range ( 118 ) and the third length range ( 122 ) respective outflow edges are formed, over which the turbine wheel ( 58 ) can be flowed from the exhaust gas. Internal combustion engine ( 10 ) according to one of the preceding claims, characterized in that in a turbine wheel outlet area a further adjusting device ( 96 ) is arranged, by means of which a Turbinenradaustrittsquerschnitt (A2) is adjustable. Internal combustion engine ( 10 ) according to claim 8, characterized in that the further adjusting device ( 96 ) for adjusting the Turbinenradaustrittsquerschnitts (A2) is displaceable in the axial direction. Internal combustion engine ( 10 ) according to one of the preceding claims, characterized in that at least one of the first blocking bodies ( 88 ) and / or at least one of the second blocking bodies in the circumferential direction of the turbine wheel ( 58 ) extends over its circumference over a wrap angle, which is in a range of including 35 degrees to 55 degrees inclusive.

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