WO2011067259A1

WO2011067259A1 - Turbocharger

Info

Publication number: WO2011067259A1
Application number: PCT/EP2010/068554
Authority: WO
Inventors: Holger Fäth; Ralf Böning
Original assignee: Continental Automotive Gmbh
Priority date: 2009-12-02
Filing date: 2010-11-30
Publication date: 2011-06-09
Also published as: DE102009056632A1

Abstract

The invention relates to a turbocharger (1), comprising a radial-axial impeller (12), which is disposed in an impeller housing (10) of the turbocharger, and wherein the impeller housing comprises a guide element (24), which forms at least a part of the rear wall (26) of an inclined or oblique spiral (16) of the impeller housing.

Description

description

Turbocharger The invention relates to a turbocharger having a radial-axial impeller, in particular a radial-axial turbine impeller.

Turbochargers generally have a turbine which is arranged in an exhaust gas flow and is connected via a shaft to a compressor in the intake tract. On the shaft, a turbine wheel and a compressor wheel are usually arranged on ^¬ . The turbine wheel of the turbine is driven by the exhaust ^¬ stream of a connected engine and in this case in turn drives the compressor of the compressor. Here ^¬ by the compressor increases the pressure in the intake manifold of the engine, so that a larger amount of air enters the cylinder during the intake stroke. This has the consequence that more oxygen is available and a correspondingly larger amount of fuel can be burned.

Turbines for a turbocharger generally differentiate between axial turbines and radial turbines. In axial turbines in this case the turbine wheel flows through only axially. In radial turbines, in turn, the flow is centripetal, i. in the radial direction from outside to inside and the outflow in the axial direction.

In addition, a radial-axial turbine can be provided with a radial-axial turbine. In this case, the exhaust gas flows in obliquely and axially out again.

To wrestlers the moment of inertia of a turbocharger rotor to ver ^¬ can a smaller diameter turbine verwen- be. When using a smaller turbine wheel, however, the mass flow rate also decreases. Thus, the diameter of the turbine wheel normally has a minimum to still generate enough drive power for the compressor. This means that the mass moment of inertia can just ^¬ if smaller, which in turn improves the run-up of the turbocharger improved.

It is known to replace the radial wheel of the turbine with a radial-axial turbine wheel (mix-flow). By this Radi ^¬ al-axial turbine wheel, the exhaust no longer flows radially hi ^¬ no and axially out or is deflected by 90 °, but the exhaust gas flows obliquely into and axially out again. The Nei ^¬ supply angle of the perpendicular / radial inflow direction is significantly greater than 0 °. The radial-axial turbine wheel can enforce more mass flow with smaller wheel diameters than the radial wheel. Thus, in the radial-axial turbine tends to be a smaller wheel can be with a lower mass moment of inertia ^¬ used as in the radial turbine. The mass moment of inertia of the radial-axial turbine wheel is additionally smaller due to the inclined leading edge and the smaller wheel back.

The problem with the exhaust gas turbocharger, especially with small sizes, is that one can constructively realize a shallow inflow angle into the wheel by tilting the spiral towards the bearing housing only when one either dispenses with the water core or the rotor, i. the support shaft and the overhang of the turbine, extended. However, the inclination of the spiral is limited by the exhaust gas temperature.

The extension of the power tool is again severely limited by the rotor dynamics or the package. A combination of a turbine housing with an almost ra ^¬ dialen inflow, with only a very small angle of inclination is given, and a radial-axial turbine can be ^¬ sets. A tongue or a tongue element of the spiral sits in such a radial-axial turbine very far away from the leading edge of the turbine wheel. However, the spacing of the tongue element has a significant influence on the thermodynamic efficiency.

The tongue element is connected to the turbine housing on both sides. The tongue element in this case has no inclination, and it also has no parallelism to A ^¬ occurs edge of the turbine on. The flow guidance of the exhaust gas flow takes place through a web of Turbinengehäu ^¬ ses of the turbine.

Accordingly, it is the object of the present invention to provide an improved turbocharger with a radial-axial impeller, in particular a radial-axial turbine impeller. This object is achieved by a turbocharger having the features of patent claim 1.

Accordingly, according to the invention, a turbocharger is provided, which has a radial-axial impeller, which is arranged in an impeller housing of the turbocharger and wherein the

Impeller housing has a guide element for guiding the flow in the impeller housing, which forms part of an inclined or obliquely formed spiral of the impeller housing. The turbocharger has the advantage that the spiral itself does not have to be inclined, but the separate guide element as part of the spiral as a flow guide element an inclined inflow of the exhaust gas in the spiral made ^¬ light. The guide element furthermore enables a compact Re construction in the axial direction, since the axial space around once the wall thickness of the impeller housing can be made smaller, as will be explained in more detail below. Furthermore, the object is achieved by a turbocharger having the features of patent claim 2.

In this case, a turbocharger is provided, which has a radial-axial impeller, which is arranged in an impeller housing of the turbocharger and wherein in the impeller housing, a tongue element is formed which the same or ei ^¬ NEN almost the same angle to the Radeintrittskante of Rad ^¬ al -Axial impeller has. The turbocharger has it he can ^¬ höht the advantage that by the paralle ^¬ le or nearly parallel array of blade angle and wheel ^¬ entering edge of the radial-axial impeller efficiency. Advantageous embodiments and modifications of the invention will become apparent from the dependent claims and the description with reference to the drawings.

The invention will be explained in more detail with reference to the exemplary embodiments shown in the schematic figures of the drawings. Show it:

1 is a partial sectional view through a turbocharger having a radial-axial turbine according to an embodiment of the invention; and

Fig. 2 is a sectional view through a turbocharger having a radial-axial turbine, according to another embodiment of the invention. In all figures, identical or functionally identical elements and devices - unless otherwise indicated - have been designated by the same reference numerals.

In Fig. 1 is now a partial sectional view through a radial-axial turbine of a turbocharger 1 according to an embodiment of the invention. The axial-radial turbine in this case has a turbine housing 10, in which an axial-radial turbine wheel 12, arranged on an impeller hub 13 impeller blades 11, is arranged. The turbine runner 12 is provided on a Wel ^¬ le, which is mounted in a bearing housing 20 of the turbocharger DERS. 1 The turbine housing 10 has a Spira ^¬ le 16 or a spiral section over which an exhaust gas stream of a connected internal combustion engine flows obliquely into and then axially out again. A tongue element (not shown) of the turbine spiral 16 is connected according to the invention not on both sides but only on one side to the turbine housing 10 or attached thereto, for example in one piece or as a separate part. Furthermore, according to the invention, the flow guidance of the exhaust gas flow in the spiral 16 is realized not only by the webs 22 in the turbine housing 10, but the bearing housing side by at least one guide element 24, which here also serves as a heat shield. The guide element 24 is formed from ^¬ so that it forms a portion of the rear wall 26 or as shown here, a complete rear wall 26 of the Spiralgehäu ^¬ ses 16 so the spiral of the turbine housing 10. The guide element 24 in this case has at least one section 28 with a predetermined slope or with a predetermined inclination, in order to angle the exhaust gas flow or with a predetermined inclination. th angle of inclination in the direction of the turbine impeller 12 to lei ^¬ th. The inclination angle 1 extends from a radial so the turbine impeller axis 15 perpendicular inflow direction of a radial turbine and the turbine rotor axis 15 as viewed to the bearing housing side as in Fig. plotted is to allow the exhaust stream with a predetermined slope to flow into the turbine housing 10, wherein the exhaust stream then flows out axially via the radial-axial turbine wheel 12 from the turbine housing 10 again. In other words, the inflow direction of the radial-axial turbine is inclined by the inclination angle in the direction of the bearing housing side of the Turbola ^¬ DERS 1 in comparison with the radial or perpendicular to a radial inflow turbine, as shown in Fig. 1.

Furthermore, preferably the tongue element 14, as will be described in more detail in the following with reference to FIG. 2, pulled very close to or as close as possible to the leading edge 18 of the turbine wheel 12 ^¬. In other words, the smallest possible distance is provided between the tongue element 14 and the leading edge 18 of the turbine runner 12, as shown in FIG. 2. In addition, the tongue element 14 is preferably inclined, wherein the tongue member 14 has as ^¬ at preferably the same angle as the Radeintrittskante 18 of the turbine wheel 12, or so nearly in Wesent ^¬ union the same angle as the Radeintrittskante 18 of the turbine runner 12 has.

The rear wall 26 of the spiral 16 of the turbine housing 10 is, as described above, inclined in the direction of the bearing housing 20. For this purpose, the guide element 24, which is also provided here as a heat shield, with a corresponding predetermined slope so formed inclined at the inclination angle to an inclination of the rear wall 26 of the spiral 16th to provide here in the direction of the bearing housing 20. As shown in Fig. 1, the guide element 24 may be formed so that it forms the complete rear wall 26 of the spiral 16 of the turbine housing 10, wherein the rear wall 26 is formed at least in a portion 28 with the inclination angle or inclination. Furthermore, the return ^¬ wall 26 is formed such that the spiral 16 and the rear ^¬ wall, which is formed by the guide element 24, 26 mög ^¬ lichst merge seamlessly into one another in order to achieve an optimal flow conduction and flow losses, for example as a result of counteract sharp transitions. In other words, the rear wall 26 of the spiral 16, which is formed by the guide element 24, adapts to the contour of the coil 16 to, as indicated by the dashed line 25 in Fig. 1, and at least further includes a ge ^¬ tended or oblique portion 28, said Ab ^¬ section 28 is inclined in the direction of the bearing housing 20 with the inclination ^¬ angle. The section 28 may be as in ^¬ as shown in Fig. 1 is shown, forming excluded in the form of a straight line to be necessary for the angle to a perpendicular

Turbinenlaufradachse 15 is inclined, or also be curved or rounded, as indicated in Fig. 2.

In Fig. 2 is a sectional view through the turbine of a turbocharger 1 according to the invention is shown. It is the

Flow direction, ie the inflow direction and the outflow ^¬ direction in Fig. 2 each schematically and greatly simplified with an arrow. The turbine also includes a turbine housing 10 having a scroll 16, and a radial-axial turbine runner 12 having an impeller hub 13 and impeller blades 11 disposed thereon. The radial-axial turbine runner 12 is disposed on a shaft 30 that is housed in a bearing housing 20 stored is. Furthermore, a guide member 24 is provided, which is formed so that it forms a rear wall 26 or part of the rear wall 26 of the spiral 16, wherein the part of the rear wall 26 or the rear wall 26 is inclined at a predetermined inclination angle in the direction of the bearing housing 20 , The portion of the guide element 24, which is arranged as the rear wall 26 or part of the rear wall 26 of the spiral 16 so the Turbi ^¬ nengehäuses 10 forms with the spiral 16 so the turbine housing 10 is a substantially seamless transition, as by the dashed line 25 is indicated. WUR as already described above with reference to FIG. 1 ^¬ de, the guide element 24 is formed so that it is possible, without transition, or continuously in the turbine housing wall above ^¬ so that the flow guide is not or as little as possible affected.

Furthermore, the guide element 24 is formed such that the rear wall section 26 merges into the turbine wheel 12, as indicated in FIGS. 1 and 2 with a dashed line 25, preferably no step or step or substantially no step or step between the rear wall section 26 and the contour of the turbine runner hub 13 is provided.

The rear wall portion 26 of the guide element 24 may be formed once as a straight surface, which is formed by the inclination ^¬ angle preferably in the direction of the bearing housing 20 ge ^¬ tended, as shown in Fig. 1. The return ^¬ wall portion 26 of the guide member 24 but can also be formed at ^¬ game as arcuate or rounded or have at least one arcuate or rounded portion 28 as shown in Fig. 2 is shown. The arcuate or rounded portion 28 may be formed inclined at an inclination angle, as indicated in Fig. 2, preferably before ^¬ in the direction of the bearing housing 20th Likewise, the rear wall portion 26 of the guide element 24 we ^¬ least have an arcuate or rounded portion 28 and a straight portion 28, wherein the rear wall section 26 at least in one of these sections inclined ^¬ formed, preferably inclined to the inclination angle to the bearing ^¬ housing side be educated.

The guide element 24, which forms the rear wall 26 or a part of the rear wall of the spiral 16, and has been described ^above with reference to the ^embodiments from ^¬ in FIGS. 2 and 3, for example, be formed as a sheet metal part and optionally take additional additional functions, such as a heat shield. In this case, the sheet metal part may be shaped or bent, that it as shown in FIGS. 1 and 2, between the bearing housing 20 and the turbine housing 10 at one or both ends attached, for example, can be clamped. In this case, the guide element 24 can also be pushed or plugged with at least one end 32, as shown in FIGS. 1 and 2, on a shoulder 34, for example, a circumferential, rotationally symmetrical shoulder of the turbocharger housing 10. Likewise, the guide element 24 can be secured to the housing 10 Turboladerge ^¬ alternatively or additionally by means of screwing and / or pinning. Also, the guiding element 24 may be made instead of sheet metal from each other for the Turbi ^¬ nengehäuse 10 suitable material or combination of materials.

As already described above with reference to FIG. 1, the turbine housing has a tongue element 14, which is preferably pulled very close or as close as possible to the leading edge 18 of the turbine wheel 12. That is, there is provided a mög ^¬ lichst small distance a between the tongue member 14 and the leading edge 18 of the turbine impeller 12th Au- In addition, the tongue element 14 is preferably inclined, the tongue element 14 preferably having the same angle as the wheel inlet edge 18 of the turbine runner 12, ie being parallel to it, as indicated in FIG. 2, or almost or substantially the same Angle as the Radeintrittskante 18 of the turbine wheel 12 has.

By the use of the guide member 24 as a flow-leading part of the axial space at once, the wall thickness of the turbine housing 10 may, for example, about 4mm, less out ^¬ leads are. The turbocharger 1 can build very compact axially and thus has significant package- so space advantages. Due to the small or smallest possible distance from the tongue element 14 to the leading edge 18 of the turbine wheel 10 and the parallel or substantially parallel arrangement of tongue angle and Radeintrittskante 18, the efficiency is higher. The inclination of the rear wall 26 of the spiral 16 of the turbine housing ^¬ nengehäuses 10 also allows a continuous in ^¬ flow into the turbine wheel 12th

Although the present invention has been described above with reference to prior ^¬ ferred embodiments, it is not limited, but in many ways modi ^¬ fizierbar.

Claims

Turbocharger (1) which has a radial-axial impeller (12) which is arranged in an impeller housing (10) of the door ^¬ boladers (1) and wherein the impeller housing (10) has a separate guide element (24), which at least one Part of the rear wall (26) of an inclined or obliquely formed spiral (16) of the impeller housing (10) forms.

Turbocharger (1) which has a radial-axial impeller (12) which is arranged in an impeller housing (10) of the door bolster ^¬ (1) and wherein in the Laufradge ^¬ housing (10) is provided a tongue element (14), having the same or an almost equal angle to the Radeintrittskante (18) of the radial-axial impeller (12).

Turbocharger according to claim 2,

characterized ,

that the impeller housing (10) has a separate guide element (24) forming a rear wall or a part ei ^¬ rear plane or an inclined obliquely formed spiral (16) of the impeller housing (10).

Turbocharger according to claim 1 or 3,

characterized ,

that the rear wall (26) or a portion (28) of the rear ^¬ wall (26) by an inclination angle () from a lowering ^¬ right from is inclined, wherein the rear wall (26) or the portion (28) (the rear wall 26 ) is seen inclined from the running ^¬ wheel in the direction of a bearing housing side of the turbocharger housing. Turbocharger according to claim 1 or 3 to 4

characterized ,

that the contour of the rear wall (26) or ei ^¬ NEN section forming (28) the rear wall portion of the guide element (24) and the contour of the Spira ^¬ lenwand in the sense of an optimal flow guide merge seamlessly as possible into each other.

Turbocharger according to claim 1 or 3 to 5

characterized ,

that the contour of the rear wall (26) or ei ^¬ NEN portion (28) forming the rear wall portion of the guide element (24) in the contour of the impeller ^¬ hub (13) in steps substantially or absatzlos passes.

A turbocharger as claimed in any one of claims 1 or 3 to 6, wherein said turbocharger is a turbocharger according to any one of claims 1 or 3 to 6;

in that the rear wall (26) or the section of the rear wall (28) is formed at least in one region as a straight or curved surface.

Turbocharger according to one of claims 2 to 7,

characterized ,

that the tongue element (14) is on one side attached to or formed or attached to the Laufradge ^¬ housing (10).

Turbocharger according to one of claims 2 to 8,

characterized ,

that the distance (a) between the tongue element (14) and the leading edge or wheel entry edge (18) of the radial-axial impeller (12) is as small as possible.

10. A turbocharger as claimed in any one of claims 2 to 9, wherein said turbocharger according to any one of claims 2 to 9, wherein:

that the tongue element (14) is inclined, where ^¬ in the tongue element (14) in particular the same or almost the same angle as the leading edge or Radeintrittskante (18) of the radial-axial impeller (12).

11. Turbocharger according to one of claims 1 or 3 to 10,

characterized ,

the guide element (24) is designed to guide the flow in the impeller housing (10) and also serves as a heat shield.

12. Turbocharger according to at least one of claims 1 or 3 to 11, characterized in that the guide element (24) is a sheet metal part or has on ^¬ .

13. Turbocharger according to at least one of claims 1 to 12, d a d e c e c e s e c e n e c e,

the impeller housing (10) is a turbine housing or a compressor housing and the radial-axial impeller (12) is a turbine wheel or a compressor wheel.