DE102015219773B4 - Turbo machine and internal combustion engine - Google Patents

Abstract

Turbomachine (100) with a compressor (110) and a turbine (120), wherein- a turbine wheel (142, 20) of the turbine (120) and a compressor wheel of the compressor (110) are attached to a turbocharger shaft (140), wherein- the turbocharger shaft (140) is rotatably mounted by means of a bearing (130), the bearing (130) having a bearing arrangement which rotatably supports the turbocharger shaft (140) in a bearing housing, and - the turbine wheel (142, 20) in a turbine chamber (10) a turbine housing (30) of the turbine (120) is rotatably arranged, wherein a bearing-side back (21.A, 21.B) of the turbine wheel (20) an inner side (31.A, 31.B) of a turbine housing wall (31) over a The wheel back space (13) in the turbine chamber (10) faces, wherein a gas, namely an exhaust gas, can flow circumferentially around an axial direction (z) in the wheel back space, and - the compressor wheel (141) in a compression chamber of a compressor housing of the compressor ( 110) is rotatably arranged, with a bearing-side The back of the compressor wheel faces an inside of a compressor housing wall via a wheel back space in the compressor chamber, wherein a gas, namely charge air, can circulate around an axial direction (z) in the wheel back space, - the turbine chamber (10) and a bearing cavity of the bearing housing ( 50) and / or the compressor chamber and a bearing cavity of the bearing housing (50) are each separated by a partition wall (40) which runs radially to the turbocharger shaft (140) and which has a turbine housing wall (31) and a bearing housing wall (51) and / or a compressor housing wall and comprises a bearing housing wall, the respective dividing wall (40) being sealed against the turbocharger shaft (140), and the dividing wall (40) being hollow, the dividing wall (40) each having one between the turbine housing wall (31) and the bearing housing wall (51) and / or comprises an annular channel (41) running between the compressor housing wall and the bearing housing wall, and the partition wall (40) and one radially to the turbocharger shaft (140) extending radial part of the turbine housing wall (31) and / or the compressor housing wall is designed entirely or partially as a heat shield, characterized in that a clear width (W) of an annular gap (RS) of the wheel back space (13) in the axial direction (z ), which prevails in a section (13r) of the wheel back space (13) extending in the radial direction (r), by means of at least one flow resistance element (1A, 1B) arranged in the section (13r) to increase a flow resistance of the gas flow along the circulating gas the radial direction (r) is changed, and - an inner side (31.A) of the heat shield carries the at least one flow resistance element (1A), the flow resistance element (1A) being in the form of a contour (KA), and thus the contour ( KA) is attached to the inside (31.A) of the turbine housing wall (31) and / or the compressor housing wall, and - the clear width (W) of the annular gap of the wheel back space (13) in the turbine chamber (10) and / or the clear width of the annular gap of the compressor wheel back space in the compressor chamber is alternately narrowed and widened in the radial direction by means of the at least one flow resistance element (1A, 1B) along the radial direction (r) extending portion (13r), wherein the flow resistance of the gas flow of the circulating gas along the radial direction (r) is formed by means of the flow resistance element (1A, 1B), which extends into the wheel back space (13) in the axial direction (z) in sections Change, namely narrowing or widening, of the annular gap (RS), the contour (KA) being formed as an alternating sequence of grooves (13N) and webs (13S) arranged in the radial direction, so that due to an alternating depth of a surface the inside (31.A) of the turbine housing wall (31) and / or the compressor housing wall generates the flow resistance in the radial direction (r) ar is.

Description

Turbo machine and internal combustion engine

• - ein Turbinenrad der Turbine und ein Verdichterrad des Verdichters an einer Turboladerwelle angebracht sind, wobei
• - die Turboladerwelle mittels einem Lager drehbar gelagert ist, insbesondere wobei das Lager eine die Turboladerwelle drehbar lagernde Lageranordnung in einem Lagergehäuse aufweist, und
• - das Turbinenrad in einer Turbinenkammer eines Turbinengehäuses der Turbine drehbar angeordnet ist, wobei ein lagerseitiger Rücken des Turbinenrades einer Innenseite einer Turbinengehäusewand über einen Radrückenraum in der Turbinenkammer zugewandt ist, wobei in dem Radrückenraum ein Gas, insbesondere Abgas, umlaufend um eine axiale Richtung strömen kann, und
• - das Verdichterrad in einer Verdichterkammer eines Verdichtergehäuses des Verdichters drehbar angeordnet ist, wobei ein lagerseitiger Rücken des Verdichterrades einer Innenseite einer Verdichtergehäusewand über einen Radrückenraum in der Verdichterkammer zugewandt ist, wobei in dem Radrückenraum ein Gas, insbesondere eine Ladeluft, umlaufend um eine axiale Richtung strömen kann.

The invention relates to a turbomachine according to the preamble of claim 1, with a compressor and a turbine, wherein

• - A turbine wheel of the turbine and a compressor wheel of the compressor are attached to a turbocharger shaft, wherein
• the turbocharger shaft is rotatably mounted by means of a bearing, in particular wherein the bearing has a bearing arrangement which rotatably supports the turbocharger shaft in a bearing housing, and
• - The turbine wheel is rotatably arranged in a turbine chamber of a turbine housing of the turbine, a bearing-side back of the turbine wheel facing an inside of a turbine housing wall via a wheel back space in the turbine chamber, wherein a gas, in particular exhaust gas, can circulate in an axial direction in the wheel back space , and
• - The compressor wheel is rotatably arranged in a compressor chamber of a compressor housing of the compressor, a bearing-side back of the compressor wheel facing an inside of a compressor housing wall via a wheel back space in the compressor chamber, a gas, in particular charge air, flowing circumferentially in an axial direction in the wheel back space can.

The invention further relates to an internal combustion engine, in particular for a watercraft or a land vehicle, preferably a utility vehicle such as a dump truck or the like.

Out WO 01/73278 A1 a radial turbine of an exhaust gas turbocharger is known. To clean and avoid harmful deposits in the radial turbine, such a radial turbine has at least one passage opening in the upstream region of the dividing wall, which connects the flow channel to the dividing gap via the cavity. In this case, a partial flow with a first pressure is branched off from a main flow of the working medium of the radial turbine acting on the flow channel. The partial flow is introduced into the separating gap formed between the dividing wall and the turbine wheel and then released into an area of the flow channel equipped with a second pressure, the first pressure being greater than the second pressure.

A turbomachine with a compressor and a turbine is regularly integrated as a turbocharger in the periphery of an internal combustion engine in order to suck in air to be supplied to the engine via the compressor of the turbomachine and to supply it to the engine as compressed charge air. The compressor is regularly driven by the turbine, which is driven by the exhaust gas emitted by the engine. An internal combustion engine can also include an air filter on the charge air side and exhaust gas aftertreatment or exhaust gas recirculation on the exhaust gas side. Furthermore, the periphery of the internal combustion engine can include suitable heat exchangers for cooling the compressed charge air and / or the exhaust gas. A turbo machine of the type mentioned at the outset can also be designed in multiple stages with a first stage and a second stage of a turbocharger; thus with a first compressor of a low pressure stage and a second compressor of a high pressure stage and with a first turbine of a high pressure stage and with a second turbine of a low pressure stage.

A turbo machine is used regularly to increase the power of the engine. As explained above, the turbocharger shaft is rotatably mounted by means of a bearing. The bearing can have a radial and / or a thrust bearing, as well as a suitable lubrication system which is filled with a lubricating fluid such as oil or the like, in order to mount the turbocharger shaft in the bearing arrangement of the bearing in a rotatable manner and with as little friction as possible.

The lubricating fluid regularly comes into contact with the turbocharger shaft and is in particular in a bearing cavity of the bearing housing. Penetration of the lubricating fluid into a turbine chamber and / or compression chamber should be prevented. Penetration of the lubricating fluid into the turbine chamber and / or compressor chamber can not only impair the exhaust gas values, but also lead to coking in the turbine or the compressor due to the increased temperature in the turbine chamber and / or the compressor chamber. Basically, this danger exists in the turbine and, albeit to a lesser extent, also in the compressor.

For example, the document discloses WO 2014/074433 A1 a turbocharger with an air cooling system for cooling an electric motor within the turbocharger.

In DE 198 45 375 A1 describes a device for cooling the flow in radial gaps formed between rotors and stators of turbomachines. This is achieved in that water is used as the cooling fluid for the stator part adjacent to the radial gap. For this purpose, at least one recess is formed either in the interior of the stator part adjacent to the radial gap or at least one cavity is arranged on the stator part.

A turbo machine mentioned at the beginning is for example in DE 11 2008 002 729 T5 disclosed. To avoid an oil leak, it is proposed there, in addition to a seal, to increase a pressure within a so-called heat shield cavity between the turbine housing wall and the bearing housing wall. For this purpose, pressure is applied to a suitable cavity between the turbine housing and the bearing housing, namely a cavity channel between the said heat shield and the bearing housing. A similar solution is in the one mentioned there US 7,086,842 B2 suggested. Such a concept, which is suitable per se, however, requires additional measures for the aforementioned housing parts and, moreover, can still be improved.

An additional problem arises from the fact that the oil tightness on the turbocharger shaft is impaired insofar as that in the turbine and / or compressor housing, i. H. An absolute pressure is generated in a wheel back space of the turbine chamber and / or in a wheel back space of the compressor chamber, so that oil can be sucked in via the seal.

In addition, it is shown, as recognized here, that axial thrusts in the turbine and the compressor can be different, so that an axial thrust resulting therefrom in one or the other direction of the bearing can initially impair the seal on the turbocharger shaft. In particular, it has been shown that an axial thrust of the turbine is comparatively large compared to the compressor, so that bearing damage can occur primarily on a counter-thrust surface.

An electrically driven turbocharger group with a streamlined back of a turbine and compressor wheel or a streamlined inside of a housing wall is shown in US 2010/0175377 A1 disclosed. Basically, it is known that geometries that are favorable to the flow are selected in order to ensure a flow resistance of a turbine wheel and / or compressor wheel in a turbine housing or compressor housing with little flow resistance.

However, the aforementioned problem is not taken into account in known turbo machines. It is desirable to take into account the oil tightness and / or the axial thrust problem in a bearing for the turbocharger shaft with an improved device, in particular an improved turbomachine and internal combustion engine.

This is where the invention begins, the object of which is to specify an improved turbo machine and an improved internal combustion engine which addresses the aforementioned problem. In particular, the turbo machine and the internal combustion engine should be designed to ensure oil tightness and / or reduced susceptibility to axial thrust, preferably both, i.e. to ensure both oil tightness and reduced susceptibility to axial thrust. In particular, a pressure in the turbine housing or compressor housing is to be increased and / or an axial thrust in the bearing is to be reduced.

The object relating to a turbo machine is achieved by the invention with a turbo machine of claim 1.

• - ein Turbinenrad der Turbine und ein Verdichterrad des Verdichters an einer Turboladerwelle angebracht sind, wobei
• - die Turboladerwelle mittels eines Lagers drehbar gelagert ist, wobei das Lager eine die Turboladerwelle drehbar lagernde Lageranordnung in einem Lagergehäuse aufweist, und
• - das Turbinenrad in einer Turbinenkammer eines Turbinengehäuses der Turbine drehbar angeordnet ist, wobei ein lagerseitiger Rücken des Turbinenrades einer Innenseite einer Turbinengehäusewand über einen Radrückenraum in der Turbinenkammer zugewandt ist, wobei in dem Radrückenraum ein Gas, nämlich ein Abgas, umlaufend um eine axiale Richtung strömen kann, und
• - das Verdichterrad in einer Verdichterkammer eines Verdichtergehäuses des Verdichters drehbar angeordnet ist, wobei ein lagerseitiger Rücken des Verdichterrades einer Innenseite einer

The invention is based on a turbo machine mentioned at the beginning with a compressor and a turbine, wherein

• - A turbine wheel of the turbine and a compressor wheel of the compressor are attached to a turbocharger shaft, wherein
• the turbocharger shaft is rotatably supported by means of a bearing, the bearing having a bearing arrangement which rotatably supports the turbocharger shaft in a bearing housing, and
• The turbine wheel is rotatably arranged in a turbine chamber of a turbine housing of the turbine, a bearing-side back of the turbine wheel facing an inside of a turbine housing wall via a wheel back space in the turbine chamber, a gas, namely an exhaust gas, flowing circumferentially in an axial direction in the wheel back space can, and
• - The compressor wheel is rotatably arranged in a compressor chamber of a compressor housing of the compressor, with a bearing-side back of the compressor wheel on an inside

Compressor housing wall faces over a wheel back space in the compressor chamber, wherein a gas, namely a charge air, can flow circumferentially around an axial direction in the wheel back space.

• - die Turbinenkammer und ein Lagerhohlraum des Lagergehäuses und/oder die Verdichterkammer und ein Lagerhohlraum des Lagergehäuses durch jeweils eine radial zur Turboladerwelle verlaufende Trennwand getrennt sind, welche eine Turbinengehäusewand und eine Lagergehäusewand und/oder eine Verdichtergehäusewand und eine Lagergehäusewand umfasst, wobei die jeweilige Trennwand gegen die Turboladerwelle abgedichtet ist, und
• - die Trennwand hohl ist, wobei die Trennwand jeweils einen zwischen Turbinengehäusewand und Lagergehäusewand und/oder einen zwischen Verdichtergehäusewand und Lagergehäusewand verlaufenden Ringkanal umfasst, und
• - die Trennwand und ein radial zur Turboladerwelle verlaufender Radialteil der Turbinengehäusewand und/oder der Verdichtergehäusewand ganz oder teilweise als ein Hitzeschild ausgebildet ist.

It is further provided according to the preamble of claim 1 that

• the turbine chamber and a bearing cavity of the bearing housing and / or the compressor chamber and a bearing cavity of the bearing housing are each separated by a partition wall running radially to the turbocharger shaft, which comprises a turbine housing wall and a bearing housing wall and / or a compressor housing wall and a bearing housing wall, wherein the respective partition is sealed against the turbocharger shaft, and
• the partition wall is hollow, the partition wall each comprising an annular channel running between the turbine housing wall and the bearing housing wall and / or between the compressor housing wall and the bearing housing wall, and
• the partition and a radial part of the turbine housing wall and / or the compressor housing wall that extends radially to the turbocharger shaft is designed entirely or partially as a heat shield.

According to the invention, it is provided in this turbomachine that a clear width of an annular gap of the wheel back space in the axial direction, which prevails in a section of the wheel back space extending in the radial direction, by means of at least one flow resistance element arranged in the section to increase a flow resistance along the gas flow of the circulating gas the radial direction is changed and an inside of the heat shield carries the at least one flow resistance element, wherein the flow resistance element is formed in the form of a contour, and thus the contour is attached to the inside of a turbine housing wall and / or compressor housing wall.

According to the invention, it is further provided in the turbomachine that the clear width of the annular gap of the wheel back space in the turbine chamber and / or the clear width of the annular gap of the compressor wheel back space in the compressor chamber is alternately narrowed and widened along the radial direction by means of the at least one flow resistance element in the section extending in the radial direction, wherein the flow resistance of the gas flow of the circulating gas along the radial direction is formed by means of the flow resistance element, which extends into the wheel back space in the axial direction for changing sections, namely narrowing or widening, of the annular gap, the Contour is formed as an alternating sequence of grooves and webs arranged in the radial direction, so that, due to an alternating depth of a surface on the inside of the turbine housing wall and / or compressor housing wall, the flow impedes tand can be generated in the radial direction.

The invention also leads within the scope of the object to an internal combustion engine of claim 11. The internal combustion engine has an engine and a turbo machine according to the invention, a charge air duct of the motor being connected to the compressor and an exhaust duct of the motor being connected to the turbine. The internal combustion engine is particularly suitable for a watercraft or a land vehicle, preferably a utility vehicle such as a tipper or the like.

The invention has recognized that a flow resistance in the wheel back space can be changed with a change in the clear width prevailing in the axial direction of an annular gap in the wheel back space. Such a flow resistance in a section extending in the radial direction can in particular be generated via a narrowing and / or widening of the clear width of the annular gap prevailing in the axial direction. For this purpose, at least one flow resistance element can be arranged in the radial section. This measure applies in principle to a turbine wheel back space and, additionally or alternatively, to a compressor wheel back space.

The concept of the invention is suitable for increasing an absolute pressure in the wheel back space at an inner radius of a region of the turbocharger shaft near the shaft in the wheel back space and thus promotes the oil tightness of a seal on a turbocharger shaft. An absolute pressure in a wheel back space is usually lower at an inner radius of a region of the turbocharger shaft close to the shaft without a flow resistance element.

In addition, the flow resistance element in the wheel back space - by increasing the absolute pressure prevailing in the wheel back space - depending on load points on the exhaust gas turbocharger, reduces or compensates for existing axial thrusts. In particular, axial thrusts in the compressor wheel back space and / or the turbine wheel back space are reduced or adjusted. This prevents axial bearing damage on a counter thrust surface.

• - jeweils mittels dem wenigstens einen Strömungswiderstandselement entlang der radialen Richtung verengt oder aufgeweitet oder abwechselnd verengt und aufgeweitet ist in dem sich in radialer Richtung erstreckenden Abschnitt. Auf diese Weise ist besonders vorteilhaft die lichte Weite mittels dem Strömungswiderstandselement zur Erhöhung eines Strömungswiderstands der Gasströmung verändert.

According to the invention it is thus provided that the clear width of the annular gap of the turbine wheel back space in the turbine chamber and / or the clear width of the annular gap of the compressor wheel back space in the compressor chamber,

• is narrowed or widened or alternately narrowed and widened by means of the at least one flow resistance element along the radial direction in the section extending in the radial direction. In this way, the clear width is changed in a particularly advantageous manner by means of the flow resistance element in order to increase a flow resistance of the gas flow.

According to the invention, the flow resistance of the gas flow of the circulating gas is thus formed along the radial direction by means of the flow resistance element, which is located in the The wheel back space extends in the axial direction for changing sections, in particular narrowing and / or widening, of the annular gap. The flow resistance element thus acts comparatively effectively.

In the context of the invention, the flow resistance of the gas flow of the circulating gas along the radial direction is thus formed by means of a flow resistance element in the form of a contour. A contour can be adapted particularly well to the flow conditions and can be attached comparatively easily.

Advantageous further developments of the invention can be found in the subclaims and indicate in detail advantageous possibilities for realizing the concept explained above within the scope of the task and with regard to further advantages.

In the context of a particularly preferred first variant, the contour can be attached, in particular applied or introduced, on the back of the turbine wheel and / or compressor wheel. In the context of a particularly preferred second variant, the contour can - additionally or alternatively - be attached, in particular applied or introduced, on the inside of a turbine housing wall and / or compressor housing wall. Both the measures of the first variant and the second variant have proven to be advantageous, alone or in combination, to narrow and / or widen the clear width of an annular gap in the wheel back space by means of at least one flow resistance element in a section extending in the radial direction.

A flow rate of the gas flow of the circulating gas along the radial direction of the wheel back space, in particular the charge air and / or the exhaust gas, is preferably given in the radial direction of the wheel back space and the flow resistance element is preferably designed such that the flow speed is in the radial direction and / or circumferential direction of the wheel back space is increased sublinearly. A particularly preferred exemplary explanation is given in detail in FIG 4 (A) shown.

In particular, there is an amount of pressure gradient in the wheel back space from an inner radius of a region of the turbocharger shaft near the shaft to an outer radius of a region of the turbocharger shaft remote from the shaft. The flow resistance element is preferably designed in such a way that the amount of the pressure gradient is less than in the case of a linear increase in the flow velocity. A particularly preferred exemplary explanation is given in detail in FIG 4 (B) shown. A relationship between flow velocity and pressure gradient results in principle according to the stream filament theory as it is described, for example, in Zierep "Fundamentals of Fluid Mechanics", 5th edition, Springer textbook on pages 45 to 56. Further details can be found in the drawing using 4th to 6th explained. The flow resistance element is preferably designed in such a way that an absolute pressure in the wheel back space at an inner radius of a region of the turbocharger shaft near the shaft has a higher magnitude than an absolute pressure in a wheel back space at an inner radius of a shaft near region of the turbocharger shaft without a flow resistance element.

According to the invention, the turbine chamber and a bearing cavity of the bearing housing and / or the compressor chamber and a bearing cavity of the bearing housing are separated by a partition wall running radially to the turbocharger shaft, which comprises a turbine housing wall and a bearing housing wall and / or a compressor housing wall and a bearing housing wall, the partition wall against the Turbocharger shaft is sealed, in particular by a sealing hub, shaft seal or the like. The concept of the invention can be implemented particularly advantageously with such a partition.

According to the invention, the partition is hollow, the partition comprising in each case an annular channel running between the turbine housing wall and the bearing housing wall and / or between the compressor housing wall and the bearing housing wall. A cavity in the partition can also be used advantageously for the concept of the invention, in particular by applying pressure to it.

According to the invention, the partition wall and / or a radial part of the turbine housing wall and / or the compressor housing wall extending radially to the turbocharger shaft is designed entirely or partially as a heat shield. As a result, a heat transfer into the bearing can advantageously be reduced or avoided. An inside of the heat shield preferably bears the flow resistance element, in particular the flow resistance element is in the form of a contour.

The partition is advantageously formed as an annular part that is separate from the bearing housing and / or from the turbine housing and / or as an annular part that is connected to the compressor housing. In particular, the heat shield is designed as a jet disk and the inside of the jet disk carries a flow resistance element in the form of a contour. The concept of the invention can thus advantageously be implemented in the context of the heat shield and the jet disk.

Embodiments of the invention will now be described below with reference to the drawing. This should not necessarily represent the embodiments to scale; rather, the drawing, where useful for explanation, is in a schematic and / or slightly distorted form. With regard to additions to the teachings that can be seen directly from the drawing, reference is made to the relevant prior art. It must be taken into account that various modifications and changes relating to the shape and detail of an embodiment can be made without deviating from the general idea of the invention. The features of the invention disclosed in the description, in the drawing and in the claims can be essential for the development of the invention both individually and in any combination. In addition, all combinations of at least two of the features disclosed in the description, the drawing and / or the claims fall within the scope of the invention. The general idea of the invention is not restricted to the exact form or the detail of the preferred embodiment shown and described below or restricted to an object which would be restricted in comparison to the object claimed in the claims. In the case of the specified measurement ranges, values lying within the stated limits should also be disclosed as limit values and be able to be used and claimed as required. For the sake of simplicity, the same reference symbols are used below for identical or similar parts or parts with an identical or similar function.

• 1 eine schematische Darstellung einer Brennkraftmaschine mit einem Motor und einer Turbomaschine gemäß einer bevorzugten Ausführungsform;
• 2 ein Detail einer Turbomaschine gemäß dem Stand der Technik, bei der ein Radrückenraum in einer Turbinenkammer eine in axialer Richtung im Wesentlichen gleichbleibende vorherrschende lichte Weite eines Ringspalts --und somit mit entsprechend hohem radialen Druckgradienten (p2'-p1')-- hat;
• 3A eine zur Erfindung gehörende erste besonders bevorzugte Ausführungsform einer Turbomaschine, bei welcher --beispielhaft bei der Turbine-- die in axialer Richtung vorherrschende lichte Weite eines Ringspalts des Radrückenraumes entlang der radialen Richtung (r) wiederholt aufgeweitet ist, wobei ein entsprechendes Strömungswiderstandselement an der Innenseite einer Turbinengehäusewand angeordnet ist;
• 3B eine nicht zur Erfindung gehörende Ausführungsform, wobei im Unterschied zu 3A ein entsprechendes Strömungswiderstandselement am Rücken des Turbinenrades anstatt an der Innenseite einer Turbinengehäusewand angeordnet ist;
• 4A, 4B eine schematische Darstellung eines Geschwindigkeitsverlaufs (A) und Druckverlaufs (B) entlang des Radius eines Starrkörperwirbels in einem Radrückenraum bei einer Ausführungsform der Erfindung im Vergleich zum Stand der Technik;
• 5 eine schematische Darstellung der Dichtigkeitsproblematik im Stand der Technik aufgrund der in 4A, 4B gestrichelt dargestellten Geschwindigkeits- und Druckverläufe;
• 6A, 6B eine schematische Prinzipskizze entsprechend der speziellen Ausführungsform der 3A, 3B welche den in 4A und 4B dargestellten durchgezogenen Geschwindigkeits- und Druckverläufen zugeordnet sind;
• 7A, 7B Details der 3A und 3B in Bezug auf eine Trennwand der Turbomaschine.

Further advantages, features and details of the invention emerge from the following description of the preferred embodiments and with reference to the drawing; this shows in:

• 1 a schematic representation of an internal combustion engine with a motor and a turbo machine according to a preferred embodiment;
• 2 a detail of a turbomachine according to the prior art, in which a wheel back space in a turbine chamber has a predominant clear width of an annular gap that is essentially constant in the axial direction - and thus with a correspondingly high radial pressure gradient (p2'-p1 ');
• 3A a first particularly preferred embodiment of a turbomachine belonging to the invention, in which - for example in the case of the turbine - the clear width of an annular gap of the wheel back space prevailing in the axial direction along the radial direction ( r ) is repeatedly expanded, a corresponding flow resistance element being arranged on the inside of a turbine housing wall;
• 3B an embodiment not belonging to the invention, wherein in contrast to 3A a corresponding flow resistance element is arranged on the back of the turbine wheel instead of on the inside of a turbine housing wall;
• 4A , 4B a schematic representation of a speed curve (A) and pressure curve (B) along the radius of a rigid body vortex in a wheel back space in an embodiment of the invention compared to the prior art;
• 5 a schematic representation of the leakage problem in the prior art due to the in 4A , 4B speed and pressure curves shown in dashed lines;
• 6A , 6B a schematic outline diagram corresponding to the special embodiment of FIG 3A , 3B which the in 4A and 4B solid speed and pressure curves shown are assigned;
• 7A , 7B Details of the 3A and 3B with respect to a partition wall of the turbo-machine.

1 shows an internal combustion engine 1000 with an engine 200 , in its charge air and exhaust gas peripherals 300 a turbo machine 100 is involved. The turbo machine 100 has a compressor 110 and a turbine 120 on, being a turbocharger shaft 140 by means of a warehouse 130 is rotatably mounted and a compressor wheel 141 of the compressor 110 and a turbine wheel 142 the turbine 120 on the turbocharger shaft 140 is appropriate. The compressor 110 is to a charge air duct 111 for charge air LL connected, with the compressor air L. is supplied from the environment via an air filter 112 from the compressor 110 is sucked in. The exhaust gas given off by the engine AG in an exhaust system 121 becomes the turbine 120 fed to the exhaust system 121 connected. The exhaust AG is then followed by exhaust gas treatment and / or exhaust gas recirculation 122 passed on. That about the exhaust AG driven turbine wheel 142 the turbine 120 drives in turn via the turbocharger shaft 140 the compressor wheel 141 of the compressor 110 to compress the air L. to charge air LL on.

2 shows a detail of a turbine for the prior art T120 with a schematically shown turbocharger shaft T140 and, on this, a rotatably mounted turbine wheel TR in a turbine chamber TK for compressing exhaust gas AG . Between the back TRR of the turbine wheel TR and an inside TGI a turbine housing wall TG is a wheel back room RR formed, with a Pressure gradient p2'-p1 ' in the radial direction. On an inside radius r1 of a region of the turbocharger shaft close to the shaft T140 there is absolute pressure p1 ' and a flow rate c1 ' a gas flow of a rigid body vortex, where the absolute pressure p1 ' is significantly lower than an absolute pressure p2 ' in an outer radius r2 a region of the turbocharger shaft remote from the shaft T140 ; ie the pressure there p2 ' of the rigid body vortex lies as well as its speed c2 ' well above the pressure p1 ' or speed c1 ' .

Because of these pressure conditions, especially in the area of the inner radius r1 , two major problems arise which have been recognized by the invention. On the one hand, lubricating fluid becomes “oil” in the axial direction z in the wheel back space RR pulled and can there due to the prevailing temperature conditions in the wheel back space RR lead to a risk of coking. The annular gap RS of the rear wheel space RR is comparatively narrow and designed with low flow resistance.

On the other hand, there may be different pressure and speed ratios p1` , c1 ' the gas flow at the turbine T120 - in contrast to the same turbocharger shaft T140 attached compressor V110 - different axial thrusts in one bearing La one, the present only symbolically between turbine T120 and compressor V110 is shown. This can lead to bearings La of the prior art, axial bearing damage occurs on a corresponding counter thrust surface.

3A and 3B show two different variants of a particularly preferred embodiment of a turbo machine. The concept of the invention is based on 3A and 3B exemplary for a turbine 120 explained, the same reference numerals being used here for identical or similar features or features with an identical or similar function for the sake of simplicity. The system of using the turbine 120 The explained invention can equally - additionally or alternatively - be applied to a compressor 110 apply even if this is an afterthought 1 is not shown below.

Shows in detail 3A and 3B a turbine 120 in two different variants of a turbo machine 100 like them in 1 is shown in detail. Both turbines 120 have a turbine wheel 20th that is in a turbine chamber 10 a turbine housing 30th is rotatably arranged. The turbine wheel 20th is present by exhaust gas AG driven radially along a radius r into a diffuser 11 the turbine chamber enters and via an outlet 12th exits axially, ie in the axial direction z , which is indicated along the axis A here. In 3A as well as in 3B can be seen that a back 21.A or. 21.B of the turbine wheel 20th an inside 31.A or. 31.B the turbine housing wall 31 is facing. Between the inside 31.A and the back 21.A the turbine 120 the 3B or between the inside 31.B and the back 21.B the turbine 120 the 3B is a wheel back room 13th in the turbine chamber 10 with an annular gap RS educated.

According to the concept of the invention, the turbine is in both embodiments 120 the 3A and 3B one in the axial direction z prevailing clear width W. a disk-like annular gap RS of the wheel back space 13th in a radial direction r extending section 13r repeatedly expanded; you could also say that is the actual width of the wheel back space 13th in the radial section 13r alternately increased and decreased, that is to say it narrows or widens alternately along the radial direction r . The present is a clear width W. with a flow resistance element 1A , 1B of jetties 13S (i.e. ring-shaped ribs) formed here as a contour KA , KB alternating with the grooves in between 13N (i.e. annular grooves) can be seen - see 7A , 7B in detail. Here is the contour KA present in the embodiment of 3A according to the concept of the invention on the inside 31 . 1A the turbine housing wall 31 appropriate and in contrast to this is the contour KB on the back 21.B of the turbine wheel 20th appropriate.

The flow resistance element 1A , 1B is designed such that a flow velocity c increases sublinearly in the radial direction and / or circumferential direction of the wheel back space, as shown in FIG 4A is shown as a solid line compared to the dashed line of the prior art. The flow resistance element 1A , 1B is also designed such that in the wheel back space 13th an amount of pressure differential p1-p2 from an inner radius r1 of a region of the turbocharger shaft close to the shaft to an outer radius r2 of a region of the turbocharger shaft remote from the shaft is less than in the case of a linear increase in a flow velocity c in the radial direction r and / or circumferential direction of the wheel back space 13th like it 4th is shown.

4A and 4B thus make it clear that - as can be seen by comparing the 5 on the one hand with the 6A (corresponding 3A) and 6B (corresponding 3B) on the other hand immediately results - an absolute pressure p1 in the wheel back room 13th in the radial section 13r at an inner radius r1 of a region of the turbocharger shaft close to the shaft has a higher magnitude compared to an absolute pressure p1 ' in a wheel back space on an inner radius of a region of the turbocharger shaft close to the shaft without a flow resistance element. This has the consequence that the tightness of a seal TD the 5 in relation to a lubricating fluid "oil" (compared to the prior art) is considerably improved.

In other words, by increasing the absolute pressure p1 according to the embodiments of 3A , 3B (respectively 6A , 6B) versus prior art pressure p1 ' the absolute pressure in the area of the turbocharger shaft close to the shaft increases - so the suction forces acting on the lubricating fluid are in the wheel back space 13th in the radial section 13r , but especially in the area of the first radius close to the wave r1 , decreases as well as the axial thrust decreases in a synergistic manner.

$$p\left(r\right)=p_1+\frac{\rho }{2}\frac{c_1^2}{r_1^2}\left(r^2-r_1^2\right),r\le r1$$

The corresponding basic formulas result from considering a rigid body vortex in the wheel back space 13th from the explanations by Zierep “Fundamentals of Fluid Mechanics” (5th edition, Springer textbook) on the streamline theory of hydro- and aerodynamics on pages 43 to 77 of chapter 3.1.3. The associated differential equation (4.16 there) and its solution (exemplary for a density p of the gas assumed to be constant; 4.27 there) is listed below as an equation. $$\frac{c^2}{r}=\frac{1}{\rho }\frac{dp}{dr}$$

$$p\left(r\right)=p_1+\frac{\rho }{2}\frac{c_1^2}{r_1^2}\left(r^2-r_1^2\right),r\le r1$$

7A and 7B show a detail of the already in 3A and 3B illustrated turbo machine 100 regarding the design of the wheel back space 13th with a section-wise narrowing and / or widening through the contour KA , KB , ie here a repeated widening of the width W. of the annular gap RS along the radial direction r as with 3A and 3B described.

In detail it can be seen there that the turbine chamber 10 and an unspecified bearing cavity of the bearing 130 with the bearing housing 50 through a radial to the turbocharger shaft 140 Hollow partition (along axis A) 40 are separated. The partition 40 each includes one between the turbine housing wall 31 and the bearing housing wall 51 extending annular channel 41 and is formed as a whole as a heat shield. The heat shield is in particular in the turbine chamber 10 facing wall of the partition 40 , including the inside 31.A , 31.B the turbine housing wall 31 , designed as a jet disk. In the embodiment of 7A is this jet disc with the aforementioned contour KA to represent a flow resistance element 1A Mistake. In the embodiment of 7B is the jet disc on its inside to the turbine chamber 10 designed flat; instead, the back carries 21.B of the turbine wheel 20th the aforementioned contour KB to form a flow resistance element 1B .

The contour KA , KB is present as an alternating sequence of grooves arranged in the radial direction 13N and bars 13S educated. The grooves 13N have an essentially semicircular base, which is not specified in more detail. The bridges 13S are essentially rectangular on their upper side. Due to the alternating depth of the surface on the inside 31.A or on the back 21.B in the radial direction r a flow resistance is generated in such a way that in the radial direction r and / or in the circumferential direction, the flow velocity c of the rigid body vortex at the rear of the turbine wheel 20th in the back of the wheel 13th is decreased and a pressure gradient p2-p1 in the radial direction r - as explained above - is also reduced. Overall, this leads to the fact that below the partition 40 a suction of oil in the bearing cavity through the seal TD no longer exists or only exists to a reduced extent. There are also axial thrusts on the bearing 130 decreased.

List of reference symbols

1A, 1B

Flow resistance element

TK, 10

Turbine chamber

11

Diffuser

12th

Outlet

13th

Rear wheel space

13r

radial section

13S

web

13N

Groove

20th

Turbine wheel

21.A, 21.B

Back of the turbine wheel of the turbine

30th

Turbine housing

31

Turbine housing wall

31.A, 31.B

Inside of the turbine housing wall

40

partition wall

50

Bearing housing

51

Bearing housing wall

1000

Internal combustion engine

100

Turbo engine

V110, 110

compressor

111

Charge air duct

112

Air filter

T120, 120

turbine

121

Exhaust gas routing

122

Exhaust gas recirculation

130

warehouse

T140, 140

Turbocharger shaft

141

Compressor wheel

142

Turbine wheel

200

engine

300

Exhaust peripherals

AG

Exhaust gas

L.

air

LL

Charge air

La

warehouse

TR, 20

Turbine wheel

TRR

Back of the turbine wheel

TG

Turbine housing wall

TGI

Inside of the turbine housing wall

TD

poetry

RR

Rear wheel space

RS

Annular gap

TGI

Turbine housing inner wall

p1, p2, p1 ', p2'

print

c1, c2, c1 ', c2'

Flow velocity

r1

Inner radius

r2

Outer radius

W.

clear width

z

axial direction

r

radial direction

KA, KB

contour

Claims (11)

Turbomachine (100) with a compressor (110) and a turbine (120), wherein - a turbine wheel (142, 20) of the turbine (120) and a compressor wheel of the compressor (110) are attached to a turbocharger shaft (140), wherein - the turbocharger shaft (140) is rotatably mounted by means of a bearing (130), the bearing (130) having a bearing arrangement which rotatably supports the turbocharger shaft (140) in a bearing housing, and - the turbine wheel (142, 20) in a turbine chamber (10) a turbine housing (30) of the turbine (120) is rotatably arranged, wherein a bearing-side back (21.A, 21.B) of the turbine wheel (20) an inner side (31.A, 31.B) of a turbine housing wall (31) over a The wheel back space (13) in the turbine chamber (10) faces, wherein a gas, namely an exhaust gas, can flow circumferentially around an axial direction (z) in the wheel back space, and - the compressor wheel (141) in a compression chamber of a compressor housing of the compressor ( 110) is rotatably arranged, with a bearing side iger back of the compressor wheel faces an inside of a compressor housing wall via a wheel back space in the compressor chamber, wherein a gas, namely charge air, can circulate around an axial direction (z) in the wheel back space - the turbine chamber (10) and a bearing cavity of the bearing housing (50) and / or the compressor chamber and a bearing cavity of the bearing housing (50) are each separated by a partition wall (40) which runs radially to the turbocharger shaft (140) and which has a turbine housing wall (31) and a bearing housing wall (51) and / or a compressor housing wall and a bearing housing wall, wherein the respective partition (40) is sealed against the turbocharger shaft (140), and - the partition (40) is hollow, the partition (40) each between the turbine housing wall (31) and the bearing housing wall (51) and / or comprises an annular channel (41) running between the compressor housing wall and the bearing housing wall, and - the partition wall (40) and one radial to the door The radial part of the turbine housing wall (31) and / or the compressor housing wall running through the bolader shaft (140) is entirely or partially designed as a heat shield, characterized in that a clear width (W) of an annular gap (RS) of the wheel back space (13) in the axial direction (e.g. ), which prevails in a section (13r) of the wheel back space (13) extending in the radial direction (r), by means of at least one flow resistance element (1A, 1B) arranged in the section (13r) to increase a flow resistance of the gas flow along the circulating gas the radial direction (r) is changed, and - an inner side (31.A) of the heat shield carries the at least one flow resistance element (1A), the flow resistance element (1A) is formed in the form of a contour (KA), and thus the contour (KA) is attached to the inside (31.A) of the turbine housing wall (31) and / or the compressor housing wall, and - the clear width (W) of the annular gap of the wheel back space ( 13) in the turbine chamber (10) and / or the clear width of the annular gap of the compressor wheel back space in the compressor chamber is alternately narrowed and widened by means of the at least one flow resistance element (1A, 1B) along the radial direction (r) in which in radial direction extending portion (13r), wherein the flow resistance of the gas flow of the circulating gas along the radial direction (r) is formed by means of the flow resistance element (1A, 1B) which extends into the wheel back space (13) in the axial direction (z) for changing sections, namely narrowing or widening, of the annular gap (RS), where - the contour (KA) as an alternating sequence of grooves (13 N) and webs (13S) is formed so that the flow resistance in the radial direction (r) can be generated due to an alternating depth of a surface on the inside (31.A) of the turbine housing wall (31) and / or compressor housing wall. Turbo machine (100) Claim 1 , characterized in that the flow resistance of the gas flow of the circulating gas along the radial direction (r) is formed by means of a further flow resistance element (1B) in the form of a contour (KB) which is placed on the back (21.B) of the turbine wheel (142, 20) and / or the compressor wheel (141) is attached. Turbo machine (100) Claim 1 , characterized in that the grooves (13N) have a semicircular base and / or the webs (13S) are rectangular on their upper side. Turbo machine (100) Claim 2 , characterized in that the contour (KA, KB) is applied or introduced. Turbo machine (100) according to one of the Claims 1 to 4th , characterized in that the partition (40) is sealed against the turbocharger shaft (140) by a sealing hub, shaft seal or the like seal. Turbo machine (100) according to one of the Claims 1 to 5 , characterized in that a flow rate (c) of the gas flow of the circulating gas, namely the charge air and / or the exhaust gas, is given along the radial direction (r) of the wheel back space and the flow resistance element (1A, 1B) is designed such that the flow velocity (c) in the radial direction (r) of the wheel back space (13) increases sublinearly. Turbo machine (100) Claim 6 , characterized in that in the wheel back space (13) there is an amount of a pressure gradient (p1-p2) from an inner radius (r1) of a region of the turbocharger shaft (140) close to the shaft to an outer radius (r2) of a region of the turbocharger shaft (140) remote from the shaft , and the flow resistance element (1A, 1B) is designed in such a way that the amount of the pressure drop (p1-p2) is less than in the case of a linear increase in the flow velocity (c) in the radial direction (r) of the wheel back space (13). Turbo machine (100) according to one of the Claims 1 to 7th , characterized in that the flow resistance element (1A, 1B) is designed such that an absolute pressure (p1) in the wheel back space (13) at an inner radius (r1) of a region of the turbocharger shaft (140) close to the shaft has a higher magnitude than an absolute one Pressure (p1 ') in a wheel back space (13) at an inner radius (r1) of a region of the turbocharger shaft (140) close to the shaft without a flow resistance element. Turbo machine (100) according to one of the Claims 1 to 8th , characterized in that the partition (40) is formed as a ring part that is separate from the bearing housing (50) and connected to it. Turbo machine (100) according to one of the Claims 1 to 9 , characterized in that the heat shield is designed as a jet disk and the inside of the jet disk carries the flow resistance element (1A) in the form of the contour (KA). Internal combustion engine (1000) with a motor (200) and a turbo machine (100) according to one of the Claims 1 to 10 , characterized in that a charge air duct (111) of the engine is connected to the compressor (110) and an exhaust gas duct (121) of the engine is connected to the turbine (120).

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