DE102018221161B4 - Exhaust gas turbine of an exhaust gas turbocharger and an exhaust gas turbocharger with a flow-related disruptive element in the turbine housing - Google Patents

Abstract

Exhaust gas turbine (20) for an exhaust gas turbocharger (1) with a turbine housing (21) having a turbine axis (3) and a turbine impeller (12) with impeller blades (121), the turbine housing (21) having an impeller space (22) in which the turbine impeller (12) is arranged centrically to the turbine axis (3) and rotatable about it, and has at least one exhaust gas feed channel (23a) which tangentially into an exhaust gas annular channel which runs around the impeller space (22) and tapers in a helical shape towards the impeller space (22) (23b), which is connected to the impeller chamber (22) via an open annular gap (25) for guiding an exhaust gas mass flow to the turbine impeller (12), wherein in the area in which the exhaust gas feed channel (23a) enters the exhaust gas annular channel ( 23b) passes over, on the side of the exhaust gas feed channel (23a) facing the annular gap (25) an inlet tongue (60) with a tongue end (61) is formed at a radial tongue distance (RT) from the turbine axis (3) A first fluidic disruptive element (65) is arranged at a first angular distance θ1 ± 10% to the end of the tongue (61), determined with reference to the turbine axis (3), and the inlet tongue (60) is arranged in the region of its tongue tip (61) ) have a tongue thickness (DT) and the first fluidic disruptive element (65) have a mean disruptive element thickness (DSEM), each in the radial direction with respect to the turbine axis (3), characterized in that the angular distance θ1 is determined according to the relationship 1 = 180 ° / EOK and EOK is the critical speed order that specifies a multiplication factor by which a design rotational frequency FR of the exhaust gas turbine (20) is to be multiplied in order to achieve the value of a critical excitation frequency FWK of the turbine runner (12), and that the mean thickness of the disturbing element (DSEM) satisfies the condition 0, 8 DT <DSEM <2 DT fulfilled.

Description

The invention relates to an exhaust gas turbine of an exhaust gas turbocharger and an exhaust gas turbocharger, in particular for an internal combustion engine, with an artificial fluidic disruptive element in the exhaust gas mass flow in the turbine housing.

Exhaust gas turbochargers with exhaust gas turbines and intake air compressors are increasingly being used to increase the performance of internal combustion engines, in particular in motor vehicle internal combustion engines. This is happening more and more often with the aim of reducing the internal combustion engine with the same or even increased performance in size and weight and at the same time reducing consumption and thus the C0 ₂ emissions with regard to increasingly stringent legal requirements in this regard. The operating principle is to use the energy contained in the exhaust gas mass flow in order to increase the pressure in the intake tract of the internal combustion engine or the internal combustion engine and thus bring about a better filling of the combustion chamber with air-oxygen and thus convert more fuel, gasoline or diesel per combustion process to be able to, i.e. to increase the performance of the internal combustion engine.

For this purpose, an exhaust gas turbocharger has an exhaust gas turbine arranged in the exhaust gas tract of the internal combustion engine with a turbine impeller driven by the exhaust gas mass flow and a radial compressor arranged in the intake tract with a compressor impeller that builds up the pressure. The turbine impeller and compressor impeller are attached to the opposite ends of a rotor shaft in a rotationally fixed manner and thus form the so-called turbo rotor, which is rotatably mounted with its rotor shaft in a rotor bearing unit arranged between the exhaust gas turbine and the radial compressor. Thus, the turbine impeller is driven with the help of the exhaust gas mass flow and the compressor impeller is in turn driven via the rotor shaft and the exhaust gas energy is used to build up pressure in the intake tract.

Exhaust gas turbines and centrifugal compressors are fluid flow machines and, due to the laws of physics, have an optimal operating range that depends on the size and type of construction and is characterized by the mass flow rate, the pressure ratio and the speed of the respective impeller. In contrast to this, the operation of an internal combustion engine in a motor vehicle is characterized by dynamic changes in the load and the operating range.

In order to be able to adapt the operating range of the exhaust gas turbocharger to changing operating ranges of the internal combustion engine and thus to ensure the desired response behavior as far as possible without noticeable delays (turbo lag), exhaust gas turbochargers are equipped, for example, with bypass channels that can be opened via valve flaps. In the exhaust gas turbine sector this is known as a wastegate device and in the radial compressor sector as a forced air circulation device. Furthermore, exhaust gas guiding devices with adjustable guide vanes, so-called variable turbine geometries (VTG), are in use.

The turbine housing has one or more annular exhaust gas channels, so-called exhaust gas flows, which encircle the turbine impeller or the impeller chamber and taper in a spiral shape towards the turbine impeller or the impeller chamber. These exhaust gas flows have a respective or common, tangentially outwardly directed exhaust gas feed channel with a manifold connection piece for connection to an exhaust manifold of an internal combustion engine, through which the exhaust gas mass flow flows into the respective exhaust gas flow.

The exhaust gas flows also each have an annular gap running at least over part of the inner circumference, which runs in at least a partial radial direction towards the turbine wheel or the impeller chamber and thus represents a connection between the respective exhaust gas annular channel and the impeller chamber, through which the Exhaust gas mass flow flows onto the turbine impeller. In the area in which the exhaust gas supply channel merges into the respective exhaust gas ring channel, a so-called entry tongue is formed on the side of the exhaust gas supply channel facing the annular gap, which at the same time forms the outgoing end of the exhaust gas ring channel, in the area in which the exhaust gas Annular channel at the end of the cycle around the impeller again meets the exhaust gas feed channel.

The turbine housing also has an exhaust gas discharge duct which runs away from the axial end of the turbine impeller in the direction of the turbocharger axis or the corresponding turbine axis and has an exhaust connection piece for connection to the exhaust system of the internal combustion engine. The exhaust gas mass flow emerging from the turbine impeller is discharged into the exhaust system of the internal combustion engine via this exhaust gas discharge duct.

During operation, the turbine housing and the turbine runner are traversed by the hot exhaust gas mass flow, which drives the turbine runner and thus the turbocharger rotor to over 250,000 revolutions per minute and heats it to over 1000 ° C. This results in very high demands on the material and design of the components, both thermally and mechanically. In the design are also and in particular Vibration-related stresses, in particular on the turbine impeller, must also be taken into account.

The excitation of vibrations, in particular of the impeller blades of the turbine impeller, takes place mainly through the exhaust gas mass flow. The excitation forces come from irregularities in the exhaust gas flow that are caused by upstream geometrical features, for example in the turbine housing. If no changes can be made to these geometric features, the turbine wheel must be designed to be robust enough to withstand the corresponding oscillation frequencies.

The rotational frequency of the turbocharger rotor specified in accordance with the performance-related design of the exhaust gas turbocharger, hereinafter referred to as the design rotational frequency, and the constructively influenceable natural oscillation frequency, also referred to as the resonance frequency, of the impeller blades of the turbine runner are of particular importance.

The critical vibration excitation acting on a respective impeller blade occurs through pressure differences, in particular pressure drop, in the flow wake of the inlet tongue. Whenever the respective impeller blade passes this area, it experiences a pressure fluctuation and thus a vibration excitation. As a rule, that is to say in a single-flow turbine housing, there is only one inlet tongue and a respective impeller blade thus passes the area of the flow trailing of the inlet tongue exactly once per rotation of the impeller. Thus, the vibration excitation of each individual impeller blade takes place with the speed frequency or with its further harmonics, that is, multiples of the speed frequency. In the vibration-related design of an exhaust gas turbine, reference is therefore always made to multiples of the rotational speed frequency at the design rotational speed, that is to say the design rotational frequency of the exhaust gas turbine. In this context, the respective multiplication factor is also referred to as the so-called speed order or engine order (EO). The speed order (EO) thus represents the number of blade vibrations per revolution of the turbine runner.

As a rule, the higher the vibration frequency, i.e. the speed order (EO), the lower the mechanical effects on the impeller blades. The turbine wheel can therefore be made more robust in that the natural oscillation frequencies of the impeller blades are increased by one or more speed orders of the exhaust gas turbocharger. A natural oscillation frequency that is at least 4 times higher than the excitation frequency is customary, so that the turbine runner is designed to be robust against oscillation excitations up to the 4th order of speed.

For example, a design speed of a maximum of 240,000 revolutions per minute results in a speed frequency of a maximum of 4,000 Hz. If the turbine impeller is designed for the 4th order of speed, the natural oscillation frequency of the turbine impeller to be aimed for is 16,000 Hz.

However, since the oscillation excitation exerted by the wake of the entry tongue contains a multitude of oscillation frequencies, in the above example an oscillation excitation can take place through the 5th speed order, which has a harmful effect on the turbine wheel.

In order to increase the natural vibration frequency of the turbine runner, the runner blades have to be designed with greater wall thicknesses, which increases the moment of inertia of the turbine runner, which in turn has a negative effect on the dynamics of the turbocharger in transient operation. It is important to avoid this.

From the US 2012/0275914 A1 an exhaust gas turbine having the features of the preamble of claim 1 is known. In this case, so-called support columns are provided on a circle surrounding the turbine rotor, which act as disruptive elements in order to improve the vibration behavior of the turbine. The width of these support columns should be minimized in order to achieve the best possible conditions.

the GB 2525305 A describes a turbine in which elements are arranged in an annular region around the circumference of the turbine wheel, which serve to absorb energy in the event of a defect in the turbine wheel by comminuting components of the turbine wheel accordingly after a defect.

The object to be achieved by means of the invention therefore consists in specifying an exhaust gas turbine for an exhaust gas turbocharger or an exhaust gas turbocharger with increased vibration resistance without having to accept the aforementioned disadvantages.

This object is achieved by an exhaust gas turbine and an exhaust gas turbocharger with the features specified in the respective independent claims. Further designs and developments of the invention are the subject of the dependent claims.

Accordingly, an exhaust gas turbine for an exhaust gas turbocharger with a turbine housing having a turbine axis and a Turbine impeller indicated with impeller blades. The turbine housing has an impeller chamber, at least one exhaust gas feed channel and one exhaust gas ring channel. In the impeller space, the turbine impeller is arranged centrically to the turbine axis and rotatable about it. The respective exhaust gas feed channel merges tangentially into the respective annular exhaust gas annular channel, which encircles the impeller space and tapers in a spiral shape towards the impeller space, which in turn is connected to the impeller space via an open annular gap for guiding an exhaust gas mass flow to the turbine impeller. In the area in which the exhaust gas feed channel merges into the exhaust gas ring channel, on the side of the exhaust gas feed channel facing the annular gap, at a radial tongue distance from the turbine axis, an entry tongue with a tongue end is formed, the entry tongue in the area of its tongue tip in _{has a tongue thickness D T in the} radial direction with respect to the turbine axis.

Weiter erfindungsgemäß ist der Winkelabstand ⊖₁ bestimmt nach der Beziehung $${\Theta }_1=180°{\text{/EO}}_{\text{K}},$$

wobei EO_K die kritische Drehzahlordnung (Engine Order) ist, die einen Multiplikationsfaktor angibt, mit dem eine Auslegungs-Drehfrequenz F_R der Abgasturbine zu multiplizieren ist, um den Wert einer kritischen Anregungsfrequenz F_W.K des Turbinenlaufrads zu erreichen. _{The exhaust gas turbine has a first fluidic disruptive element (hereinafter also simply referred to as disruptive element)} in a flow wake of the inlet tongue at a first angular distance ⊖ 1 ± 10% to the tongue end determined with reference to the turbine axis, the disruptive element in the radial direction with reference to the turbine axis has an average disruptive element thickness D _SEM . According to the invention, the mean interfering element thickness D _SEM fulfills the condition $$0.8{\text{D.}}_{\text{T}}<{\text{D.}}_{\text{SEM}}<2{\text{D.}}_{\text{T}}.$$

According to the invention, the angular distance ⊖ _{1 is} determined according to the relationship $${\Theta }_{}$$$${}_1=180°{\text{/ EO}}_{\text{K}},$$

where EO _{K is} the critical speed order (engine order), which specifies a multiplication factor with which a design rotational frequency F _{R of} the exhaust gas turbine is to be multiplied in order to achieve the value of a critical excitation _{frequency F WK of} the turbine runner.

In other words, a first disruptive element is arranged in the fluidic wake of the inlet _{tongue formed in the turbine housing at a certain angular distance, referred to as ⊖ 1} , to the tongue end within a tolerance range of ± 10%. This results in ⊖ ₁ by dividing 180 ° by a critical speed order EO _{K of} the exhaust gas turbine.

The positive effect of the invention is essentially based on the fact that both the inlet tongue and the additionally introduced first disruptive element generate a wake with a reduced pressure level in the flow of the exhaust gas mass flow. With an appropriate arrangement of the interfering element, a damping effect can be realized with a counter pulse, which greatly reduces the vibration excitation of a critical speed order. This is an out-of-phase vibration excitation in the area of the lag of the interfering element. The first disruptive element should therefore generate an excitation force precisely when the passing impeller blade is currently in the counter-oscillation. The phase position and thus the angular spacing of the interfering element is the determining factor for achieving the desired effect.

Thus, the vibration resistance of the turbine impeller and thus of the entire exhaust gas turbine is advantageously increased by at least one speed order without having to make any other structural or design changes. Conversely, when using the invention, a turbine runner can be designed for natural frequencies lower by one order of speed without reducing the fatigue strength of the exhaust gas turbine as a whole. This enables lighter and more efficient turbine runners. A possibly disadvantageous effect for the performance of the turbine, which is to be expected due to the disruption of the flow of the exhaust gas mass flow, can thus be demonstrably overcompensated. However, as described above, it is also possible to improve an exhaust gas turbine, the life of which is insufficient due to vibrations, without adversely adapting the design of the turbine impeller.

Furthermore, the thickness of the respective interfering element in relation to the thickness of the entry tongue has an influence on the strength and geometry of the wake and thus on the vibration excitation or vibration damping of the impeller blades, that is to say of the turbine impeller. Thus, by choosing the average interfering element thickness D _SEM within the stated limits in relation to the tongue thickness D _{T of} the entry tab, the vibration-damping effect of the interfering elements can be positively influenced.

In an advantageous embodiment of the exhaust gas turbine, the turbine runner is designed in such a way that the critical excitation _{frequency F WK of} the turbine runner, within a tolerance range of ± 15%, is an integral multiple N greater than the design rotational frequency F _{R of} the exhaust gas turbine according to F _WK = (F _R * N) is ± 15%. The critical excitation _{frequency F WK of} the turbine wheel thus advantageously coincides with the oscillation frequency of the respective speed order EO _N = N corresponding to the multiple N.

In a further refinement of the aforementioned embodiment of the exhaust gas turbine, the critical value is The excitation _{frequency F WK of} the turbine runner is four times, five times or six times the design rotational frequency F _{R of} the exhaust gas turbine. As a result, the critical excitation _{frequency F WK of} the turbine wheel is raised to a level at which the vibration excitation is advantageously reduced.

For the example one on the 4th speed order E04 designed, ie "EO4-resistant" turbine impeller, which is usually in the 5th speed order E05 is most excited, i.e. the 5th speed order E05 corresponds to the critical speed order EOK (EOK = E05), the ideal angular distance ⊖1 of the first fluidic disruptive element is 180 ° / 5 = 36 ° ± 10%, i.e. approximately between 32.5 ° and 39.5 °. The aim is to lower the excitation forces acting in the 5th order of speed EO ₅ below the damaging level of the next critical, usually the 6th order of speed, EO ₆ . As a result, the turbine impeller achieves a service life determined by the fatigue strength (HCF, high cycle fatigue), which otherwise could only be achieved by means of impeller blades that are designed to be stiffer by one order of speed and thus thicker or shortened.

An exhaust gas turbocharger according to the invention for an internal combustion engine has a radial compressor for compressing the intake air of the internal combustion engine, a rotor bearing unit for rotating the turbocharger rotor and an exhaust gas turbine for driving by the exhaust gas mass flow of the internal combustion engine. The exhaust gas turbine is designed in accordance with one of the explanations set out above and below.

A selection of further exemplary embodiments and developments of the invention as well as various possible combinations of features of different designs are explained in more detail below with reference to the representations in the drawing.

• 1 eine vereinfachte dreidimensionale Darstellung eines erfindungsgemäßen Abgasturboladers mit im Viertelschnitt entlang der Turboladerachse aufgeschnittenem Gehäuse;
• 2 und 3 jeweils eine vereinfachte Darstellung eines Turbinengehäuses einer Ausführung einer erfindungsgemäßen Abgasturbine geschnitten in einer Ebene quer zur Turbinenachse;
• 4 verschiedene vereinfachte Schnitt-Darstellungen, a) , b) , c), von unterschiedlichen Ausführungen einer erfindungsgemäßen Abgasturbine;
• 5 Darstellungen, i) bis vi) , verschiedener Ausführungen von strömungstechnischen Störelementen, im Längsschnitt geschnitten längs ihrer jeweiligen Störelementachse;
• 6 Darstellungen, I) bis V) , verschiedener Ausführungen von strömungstechnischen Störelementen, im Querschnitt geschnitten quer zu ihrer jeweiligen Störelementachse und
• 7 eine vergrößert hervorgehobene Darstellung der Anordnung von Eintrittszunge und strömungstechnischem Störelement, in Schnittdarstellung quer zur Turbinenachse.

Show it:

• 1 a simplified three-dimensional representation of an exhaust gas turbocharger according to the invention with a housing cut open in quarter section along the turbocharger axis;
• 2 and 3 each a simplified representation of a turbine housing of an embodiment of an exhaust gas turbine according to the invention cut in a plane transverse to the turbine axis;
• 4th various simplified sectional representations, a), b), c), of different designs of an exhaust gas turbine according to the invention;
• 5 Representations, i) to vi), of various designs of fluidic disruptive elements, in a longitudinal section along their respective disruptive element axis;
• 6th Representations, I) to V), different versions of fluidic disruptive elements, in cross-section cut transversely to their respective disruptive element axis and
• 7th an enlarged, highlighted representation of the arrangement of the inlet tongue and fluidic disruptive element, in a sectional view transversely to the turbine axis.

Parts with the same function and names are identified throughout the figures with the same reference symbols.

In 1 is an embodiment of an exhaust gas turbocharger according to the invention 1 shown, consisting of exhaust gas turbine 20th , Centrifugal compressor 30th and the rotor bearing unit arranged axially therebetween 40 . To make the fluidic disruptive element according to the invention visible 65 is along the turbocharger axis 11 continuous an upper quarter of the turbine housing 21 of the compressor housing 31 and the bearing housing 41 cut out. The sectional view allows an insight into the structure and the arrangement of the essential components of the exhaust gas turbocharger 1 .

These are the turbine housings that can be arranged in the exhaust gas tract of the internal combustion engine 21 , the compressor housing that can be arranged in the intake tract of the internal combustion engine 31 and between turbine housing 21 and compressor housing 31 the bearing housing 41 the rotor bearing unit 40 on a common turbocharger axis 11 arranged one behind the other and connected to one another in terms of assembly technology.

The so-called turbocharger runner 10 of the exhaust gas turbocharger 1 consists of the turbine runner 12th with impeller blades 121 , the compressor impeller 13th as well as the rotor shaft 14th . The turbine runner 12th and the compressor impeller 13th are on the opposite ends of the common rotor shaft 14th arranged and rotatably connected to these. The rotor shaft 14th extends in the direction of the turbocharger axis 11 axially through the rotor bearing unit 40 and is rotatably mounted in this by means of radial bearings and an axial bearing axially and radially around its longitudinal axis, the rotor axis of rotation, the rotor axis of rotation in the turbocharger axis 11 lies, so coincides with this. The turbocharger runner 10 rotates around the rotor axis of rotation of the rotor shaft during operation 14th . The rotor axis of rotation and at the same time the turbocharger axis 11 are shown by the drawn center line and identify the axial alignment of the exhaust gas turbocharger 1 .

In the compressor housing 31 is the compressor impeller 13th arranged centrally, the compressor housing 31 a compressor ring channel arranged around the compressor impeller 32 to discharge the compressed air mass flow.

In the turbine housing 21 is the turbine runner 12th centric to the turbine axis 3 that are also with the turbocharger axle 11 coincides in the impeller room 22nd arranged, the turbine housing 21 an exhaust gas supply duct 23a and one around the turbine runner 12th and the impeller room 22nd arranged exhaust gas ring channel 23b having. The exhaust gas feed channel goes here 23a tangentially into the ring around the impeller space 22nd revolving, spiral to the impeller space 22nd tapering exhaust gas ring channel 23b above. The exhaust ring duct 23b is with the impeller room 22nd via an open annular gap 25th for guiding one through the exhaust gas feed duct into the turbine housing 21 entering exhaust gas mass flow M _EX on the turbine runner 12th tied together.

It is in the area in which the exhaust gas feed channel 23a into the exhaust gas ring channel 23b passes over (cut out in the illustration to make the entry tongue visible 60 ), on the annular gap 25th facing inside of the exhaust gas feed channel 23a , at a radial tongue distance to the turbine axis 3 an entry tongue 60 with a tongue end 61 educated.

How to continue in 1 recognizable, is in the flow wake of the inlet tongue 60 in one with reference to the turbine axis 3 determined first angular distance ⊖ ₁ ± 10% to the tongue end 61 a first fluidic disruptive element 65 in the radial transition area between the exhaust gas ring duct 23b and annular gap 25th arranged.

The arrangement of the first interfering element at an angular distance ⊖ ₁ ± 10% to the end of the tongue 61 is easily recognizable in 2 shown. In the cross section of the turbine housing 21 is the exhaust gas feed duct 23a , which merges tangentially into the ring around the impeller space 22nd revolving, spiral to the impeller space 22nd tapering exhaust gas ring channel 23b , good to see.

Also the entry tongue 60 with the end of her tongue 61 that is in the area in which the exhaust gas feed duct 23a into the exhaust gas ring channel 23b passes, on the the annular gap 25th facing radial inside of the exhaust gas feed channel 23a in a radial tongue distance R _T , in particular the tongue end 61 , to the turbine axis 3 is formed is clearly recognizable. The one through the exhaust gas feed duct 23a entering exhaust gas mass flow M _EX is marked with an arrow.

wobei EO_K die kritische Drehzahlordnung ist, die einen Multiplikationsfaktor angibt, mit dem eine Auslegungs-Drehfrequenz F_R der Abgasturbine 20 zu multiplizieren ist, um den Wert einer kritischen Anregungsfrequenz F_WK des Turbinenlaufrads (12) zu erreichen. Mit anderen Worten ist EO_K die Drehzahlordnung, bei der eine kritische Schwingungsanregung des Turbinenlaufrads zu erwarten ist, die also die Eigenfrequenz des Turbinenlaufrads mit guter Näherung trifft.At the same radial distance from the turbine axis 3 like the end of the tongue 61 is the first disruptive element 65 at an angular distance ⊖ ₁ ± 10% from the end of the tongue 61 arranged. The angular distance ⊖ ₁ is determined according to the relationship $${\Theta }_1=180°{\text{/ EO}}_{\text{K}},$$

where EO _{K is} the critical speed order which specifies a multiplication factor with which a design rotational frequency F _{R of} the exhaust gas turbine 20th must be multiplied in order to obtain the value of a critical excitation frequency F _{WK of} the turbine runner ( 12th ) to reach. In other words, EO _{K is} the speed order at which a critical vibration excitation of the turbine runner is to be expected, which therefore approximates the natural frequency of the turbine runner.

In 3 is in largely with 2 A further previously not mentioned embodiment of an exhaust gas turbine according to the invention is shown in a corresponding representation. This embodiment is characterized in that in the flow wake of the first flow-related disruptive element 65 at a certain angular distance θ ₂ ± 10% to the end of the tongue 61 another fluidic disruptive element 66 is arranged, wherein the angular distance θ _{2 is} determined according to the relationship θ ₂ = θ ₁ + (180 ° / EO _K ), where EO _{K is} selected as described above. The other disruptive element 66 is therefore located in a with respect to the natural oscillation of the turbine wheel 12th such a selected distance from the tongue end 61 that the wake of the second disruptive element in turn excites vibrations in phase opposition to the impeller blades 121 brings and thus advantageous for further damping of the natural vibrations of the turbine runner 12th contributes.

erfüllt, wobei R_{SE 1,2} der radiale Abstand des jeweiligen ersten oder zweiten strömungstechnischen Störelements (65, 66) zur Turbinenachse (3) ist. Dies ermöglicht vorteilhaft die Optimierung der Position der Störelemente im Hinblick auf die schwingungsdämpfende Wirkung.Furthermore, in 3 indicated that both the first and the further interfering element 65 , 66 at a respective radial distance R _SE1 , R _SE2 with respect to the turbine axis 3 is arranged with the radial distance, in particular the tongue end 61 , the entry tongue 60 , so with the radial tongue spacing R _T , coincides. It has been found, however, that the respective radial position R _SE1 , R _{SE2 of} the first and the further interfering element 65 , 66 , with regard to the optimization of the respective fluidic wake and thus its vibration-damping effect, _{can lie in a range with reference to the radial tongue spacing R T} , which the condition $$0.5{\text{R.}}_{\text{T}}<{\text{R.}}_{\text{SE}1.2}<2{\text{R.}}_{\text{T}}$$

fulfilled, where R _{SE 1,2 is} the radial distance of the respective first or second fluidic disruptive element ( 65 , 66 ) to the turbine axis ( 3 ) is. this advantageously enables the position of the interfering elements to be optimized with regard to the vibration-damping effect.

Further embodiments of the exhaust gas turbine according to the invention not mentioned so far 20th are represented by the representations a), b) and c) in the 4th made clear. The embodiments shown are characterized in that the first and / or the further flow-related disruptive element 65, 66 are in each case predominantly transverse to the direction of flow of the exhaust gas mass flow M _EX along a respective interfering element axis 67 extend. The respective interfering element can be different depending on its respective radial distance from the turbine axis 3 Over an entire clear width or only part of a clear width of the exhaust gas ring duct 23b or the annular gap 25th of the turbine housing 21 extend. To make this clear, in 4th in illustration a) an exhaust gas turbine 20th in cross section in analogy to the 2 and 3 shown with cutting planes XX and YY. In the representations b) and c) there are then sections according to section plane XX, which intersects the first interfering element in longitudinal section, through two different versions of the exhaust gas turbine 20th shown. In both representations b) and c) it can be seen that the cut interfering element 65 transverse to the direction of flow of the exhaust gas mass flow M _EX , along a respective interfering element axis 67 extends.

Although not clearly recognizable in this view, it can be assumed that the interfering element 65 extends predominantly transversely to the direction of flow. Predominantly transverse to the direction of flow means, in case of doubt, at an angle greater than 45 ° obliquely to the direction of flow up to 90 ° or greater than 90 ° up to less than 135 °, i.e. starting from its respective base against the flow direction of the exhaust gas mass flow M _EX or in the flow direction of the exhaust gas mass flow M _EX inclined, but mostly transverse to the direction of flow.

The is clearly recognizable in illustration b) 4th that the disruptive element 65 at its radial position over the entire clear width of the exhaust gas ring duct 23b of the turbine housing 21 extends. In contrast, in illustration c) the 4th recognizable that the interfering element 65 at its radial position only over part of the clear width of the annular gap 25th of the turbine housing 21 extends.

The representations of the 4th although each show only a first interfering element 65 However, the same applies to any further interfering element that may be present.

5 shows in the representations i) to vi) different geometries of interfering elements of different designs of exhaust gas turbines according to the invention 20th isolated from the turbine housing and in a view according to that shown in illustration a) of 4th Section plane YY shown using the example of the first interfering element 65 .

The resulting versions of the exhaust gas turbine 20th are characterized in that the first or the further fluidic disruptive element 65 , 66 or both disruptive elements 65 , 66 each have a cross section perpendicular to its interfering element axis 67 exhibit. The representations i), ii) and iii) show interfering elements 65 which, starting from a respective base, for example on the turbine housing 21 , over their entire extent along the respective interfering element axis 67 have a constant cross-section. The disruptive element shown in illustration i) runs here 65 transversely, i.e. at an angle of 90 °, to the direction of flow of the indicated exhaust gas mass flow M _EX and the statements according to representations ii) and iii) run predominantly transversely, i.e. at an angle of less than 90 ° and greater than 45 ° (representation i)) or between> 90 ° and <135 ° (representation ii)) to the direction of flow of the indicated exhaust gas mass flow M _EX . In cases ii) and iii), the angular spacing θ ₁ or θ ₂ relates to that with respect to the exhaust gas mass flow M _EX central position of the respective interfering element 65 , 66 .

The further representations iv) to vi) show interfering elements 65 , the cross section of which extends at least over part or the entire extent of the interfering element 65 , 66 along the respective interfering element axis 67 change. Thus, illustration iv) shows a cross-section that decreases starting from the base, illustration v) shows a cross-section that increases starting from the base, and illustration vi) shows an initially decreasing and then increasing cross-section. The different design variants of the disruptive elements 65 , 66 enable optimization of the generated lag and thus the vibration-damping effect.

The representations, I) to V) of the 6th show further different designs of fluidic disruptive elements using the example of the first disruptive element 65 in cross section, cut transversely to their respective interfering element axis 67 . The embodiments shown are characterized in that the first and / or the further fluidic disruptive element 65 , 66 each have a cross section perpendicular to its interfering element axis 67 which has a polygonal geometry as shown in illustration I) or a circular geometry as shown in illustration II) or an oval geometry as shown in illustration III) or a two-flat geometry as shown in illustration IV) or a guide vane geometry as shown in illustration V). These different design variants of the disruptive elements 65 , 66 represent further design options for optimizing the generated lag and thus the vibration-damping effect.

erfüllt. 7th shows an enlarged, highlighted representation of the arrangement of the entry tongue 61 and a fluidic disruptive element 65 , in a sectional view transverse to the turbine axis 3 . A further feature of the exhaust gas turbine should be based on this representation 20th be explained, which is characterized in that the entry tongue 60 in the area of the tip of your tongue 61 a tongue thickness D _T and a respective fluidic disruptive element 65 , 66 a mean interfering element thickness D _{SEM in} each case in the radial direction R with respect to the turbine axis 3 has, wherein the mean impurity element thickness D _SEM the condition $$0.8{\text{D.}}_{\text{T}}<{\text{D.}}_{\text{SEM}}<2{\text{D.}}_{\text{T}}$$

Fulfills.

Here, D _T denotes the tongue thickness of the entry tongue 60 in the outflow area of the exhaust gas mass flow M _EX , i.e. in the area in which the exhaust gas mass flow is M _EX from the end of the tongue 61 the entry tongue 60 replaces. Furthermore, D _SEM indicates the mean thickness of the interfering element of the respective fluidic interfering element ( 65 , 66 ), whereby reference is made to the mean interfering element thickness D _SEM , since, as described above, the cross section of the respective interfering element 65 , 66 transverse to the interfering element axis 67 and thus the interfering element thickness can also change over the axial extent of the interfering element.

Claims (9)

Exhaust gas turbine (20) for an exhaust gas turbocharger (1) with a turbine housing (21) having a turbine axis (3) and a turbine impeller (12) with impeller blades (121), the turbine housing (21) having an impeller space (22) in which the turbine impeller (12) is arranged centrically to the turbine axis (3) and rotatable about it, and has at least one exhaust gas feed channel (23a), which tangentially into an exhaust gas ring channel that runs around the impeller space (22) and tapers in a helical shape towards the impeller space (22) (23b), which is connected to the impeller space (22) via an open annular gap (25) for guiding an exhaust gas mass flow to the turbine impeller (12), wherein in the area in which the exhaust gas supply channel (23a) enters the exhaust gas annular channel ( 23b) passes, on the side of the exhaust gas feed channel (23a) facing the annular gap (25), an inlet tongue (60) with a tongue end (61) is formed _{at a radial tongue distance (R T) from the turbine axis (3), with a tongue end (61) being formed in a In the wake of the flow of the inlet tongue (60) at a first angular distance θ 1} ± 10% to the tongue end (61), determined with reference to the turbine axis (3), a first fluidic disruptive element (65) is arranged and the inlet tongue (60) in the area of its The tongue tip (61) has a tongue thickness (D _T ) and the first fluidic disruptive element (65) has an average disruptive element thickness (D _SEM ), each in the radial direction with respect to the turbine axis (3), characterized in that the angular distance θ _{1 is} determined is after the relationship $${\Theta }_1=180°{\text{/ EO}}_{\text{K}}$$

and EO _{K is} the critical speed order which specifies a multiplication factor with which a design rotational frequency F _{R of} the exhaust gas turbine (20) is to be multiplied in order to achieve the value of a critical excitation _{frequency F WK of} the turbine rotor (12), and that the mean Interfering element thickness (D _SEM ) the condition $$0.8{\text{D.}}_{\text{T}}<{\text{D.}}_{\text{SEM}}<2{\text{D.}}_{\text{T}}$$

Fulfills. Exhaust gas turbine (20) Claim 1 , characterized in that the turbine runner (12) is designed so that the critical excitation _{frequency F WK of} the turbine runner (12) is within a tolerance range of ± 15% as an integral multiple N greater than the design rotational frequency F _{R of} the exhaust gas turbine (20) is determined according to F _WK = (F _R * N) ± 15%. Exhaust gas turbine (20) Claim 2 , characterized in that the critical excitation _{frequency F WK of} the turbine runner (12) is four times, five times or six times the design rotational frequency F _{R of} the exhaust gas turbine (20). Exhaust gas turbine (20) according to one of the preceding claims, characterized in that a further fluidic interference element (66) is arranged in the flow wake of the first fluidic disruptive element (65) at a certain angular distance θ ₂ ± 10% from the tongue end (61), wherein the angular distance θ _{2 is} determined according to the relationship θ ₂ = θ ₁ + (180 ° / EO _K ). Exhaust gas turbine (20) according to one of the preceding claims, characterized in that the first and / or a further flow-related disruptive element (65, 66) in a respective radial The distance to the turbine axis (3) is arranged in the flow wake of the inlet tongue (60) in the turbine housing (21), which fulfills the condition $$0.5{\text{R.}}_{\text{T}}<{\text{R.}}_{\text{SE}1.2}<2{\text{R.}}_{\text{T}}$$

fulfilled, where R _{T is} the radial distance between the tongue of the inlet tongue (60) and R _{SE 1,2 is} the radial distance between the respective fluidic disruptive element (65, 66) and the turbine axis (3). Exhaust gas turbine (20) according to one of the preceding claims, characterized in that the first and / or a further flow-related disruptive element (65,66) each predominantly transversely to the flow direction of the exhaust gas mass flow M _Ex along a respective disruptive element axis (67) each over an entire or extend only part of a clear width of the exhaust gas annular channel (23b) or the annular gap (25) of the turbine housing (21). Exhaust gas turbine (20) Claim 6 , characterized in that the first and / or a further fluidic disruptive element (65,66) each has a cross section perpendicular to its disruptive element axis (67), which extends at least over part or the entire extension of the disruptive element (65, 66) along the respective interfering element axis (67) changes. Exhaust turbine (20) according to one of the Claims 6 or 7th , characterized in that the first and / or the further fluidic disruptive element (65,66) each has a cross section perpendicular to its disruptive element axis (67), which has a polygonal geometry or a circular geometry or an oval geometry or a two-flat geometry or a guide vane geometry. Exhaust gas turbocharger (1) for an internal combustion engine with a radial compressor (30), a rotor bearing unit (40) and an exhaust gas turbine (20), the exhaust gas turbine (20) being designed according to one of the preceding claims.

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