Turbine wheel

Abstract

To provide a turbine wheel in a charging device capable of further improving efficiency of the charging device in being operated in an internal combustion engine, in particular, to be used in an internal combustion engine.SOLUTION: A turbine wheel 10 includes a plurality of blades 12 on a hub 16 forming a rear wall 14, the adjacent blades 12 have an inlet surface 18 having two front edges 20 and two rear edges 24, and form an outlet surface 22 substantially positioned at an axial inner side, a surface 26 of the blade 12 can be constituted on the basis of angles and lengths of a plurality of curved portions positioned in adjacent to each other between the front edge 20 and the rear edge 24, and in each of the curved portions, the angle of the front edge 20 is increased first or kept constant, and then gradually decreased in accordance with increase of the length to have a maximum value.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] Cross - reference to related applications The present invention relates to a turbine wheel, particularly for use in an internal combustion engine Turbocharger and to a turbine wheel in the context thereof.

Background Art

[0002] It is known in a broader prior art that a turbine wheel drives a compressor wheel of a compressor. The turbine and compressor wheels are arranged on a common rotor rotatably supported within a bearing housing. The turbine wheel is driven by the flow of exhaust gas. The compressor is arranged within the intake manifold of an internal combustion engine. The exhaust gas turbocharger is

[0003] In this type of Turbocharger Turbocharger wherein the compressor wheel is driven by the turbine wheel, in this case, the design of the turbine wheel, particularly with respect to the geometric shape of the blade wheel, can influence the output of

[0004] An example of a turbine wheel is known from EP 1 828 543A1. The turbine wheel described therein includes a hub, a plurality of blades, and a back plate. Some of the blades include an exducer portion having a trailing edge and an inducer portion having a leading edge. The inducer has a positive local blade angle along the leading edge (with respect to the intended direction of rotation of the turbine wheel), and the angle increases from a point on the leading edge near the shroud end to a point on the trailing edge near the back plate end.

[0005] ​JP-H 11 190 201 A discloses that engine exhaust gas in the turbine housing flows into the turbine wheel through the volute. At the design point, the relative inflow angle of the exhaust gas matches the inlet blade angle with respect to the wheel, and as a result, the exhaust gas flows uniformly along the wheel blades. Away from the design point, there is a difference between the relative inflow angle and the inlet blade angle. When the flow at the leading edge of the wheel moves at a large incidence angle, the eddy originating from the exposed part with a backswept angle is a helical vertical eddy moving parallel to the flow, and in this case, the central axis is positioned parallel to the flow.

Summary of the Invention

Problems to be Solved by the Invention

[0006] Based on this prior art, the object of the present invention is to be able to further improve the Turbocharger efficiency when operating in an internal combustion engine, and in particular, to provide a Turbocharger turbine wheel for use in an internal combustion engine.

[0007] This object is achieved by the independent claims. Further preferred embodiments of the present invention are the subject matter of the dependent claims. These claims can be combined with each other in a technically useful way. The detailed description, particularly within the context of the drawings, further characterizes and clearly states the present invention.

Means for Solving the Problems

[0008] According to the present invention, a turbine wheel, in particular, one used in an internal combustion engine TurbochargerA turbine wheel, wherein the turbine wheel includes a plurality of blades on a hub forming a rear wall, adjacent blades have an inlet surface with two leading edges and an outlet surface with two trailing edges located substantially axially inward, and the surface of the blade can be configured by the angles and lengths of a plurality of curvatures positioned adjacent to each other between the leading edge and the trailing edge. In each curvature, a turbine wheel is provided in which the angle of the leading edge first increases or remains constant and then decreases to form a maximum as the length increases.

[0009] Accordingly, according to the present invention, a turbine wheel is embodied in which the blade surface is constituted by a plurality of curvatures positioned adjacent to each other. In this context, the curvatures are described in a coordinate system constituted by an angle and a length based on the wheel, and what is characteristic is the formation of a maximum value. In this case, the length follows the path between the inlet surface and the outlet surface in order to achieve acceleration during the operation of the turbine wheel by such blades formed, for example, in a turbocharger of an internal combustion engine. This acceleration is shifted closer towards the outlet surface compared to the prior art. This geometric shape of the turbine wheel according to the present invention causes a reduction in its moment of inertia and enables faster acceleration at the start of the internal combustion engine. Furthermore, this way, the level of the thermodynamic efficiency of the turbine wheel according to the present invention, which can be achieved especially during the interaction with additional components in an arrangement having a variable turbine geometry, is improved.

[0010] According to an embodiment of the present invention, the angle is formed as a polar angle and the length is formed along the rotation axis around the rotation direction.

[0011] According to this approach, the wheel-based coordinate system is formed from the polar angle and length along the axis of rotation around the direction of rotation of the turbine wheel in a manner commonly used in this field. This type of representation is common in the field of turbine wheels, enabling a direct comparison with turbine wheels from the prior art.

[0012] The zero point of the angle can be selected to increase along the leading edge in the direction of rotation. Additionally, the length can be normalized along the axis of rotation.

[0013] The latter approach is also related to measurements commonly used in this field. As a result, comparisons for characteristic features are possible for blades with various shapes. In particular, in that context, for example, the relevant angle always starts at the zero point regardless of the actual starting point of the curvature. Since the path along the curvature between the inlet and outlet surfaces generally has a varying length, it is useful to normalize the length. Furthermore, an alternative representation can be calculated from the relevant metal angle, which is calculated as the difference value between the angle and the meridian locus defined above.

[0014] According to a further embodiment of the present invention, a plurality of curvatures start at the transition between the blade and the hub and are formed to continue to the outer edge of the blade. In this case, the plurality of curvatures can be selected to be equidistantly spaced. Additionally, the plurality of curvatures can be arranged at the center of the blade.

[0015] Accordingly, a group of curved portions is generated, each of which is composed of a plurality of curved portions starting from the leading edge and reaching the trailing edge, to form the surface of the blade. Since the region related to the thermodynamic characteristics of the turbine wheel is arranged between the leading edge and the trailing edge, it is sufficient to characterize the blade surface between these points. By making it possible to be spaced at equal intervals, each curved portion starts, for example, at values of 0%, 25%, 50%, 75%, and 100% of the length of the leading edge as starting points and ends at the corresponding points on the trailing edge. The curved portion located at 0% of the leading edge is often called the hub section in this context, while the curved portion starting at 100% of the leading edge is called the outer section. In this case, the curved portion is arranged in the center of the blade between the suction side and the pressure side.

[0016] According to a further embodiment of the present invention, the angle of the relevant curved portion first increases at the transition portion between the blade and the hub, reaches its maximum value in the region of 40% - 50% of the length, and then decreases.

[0017] The so-called hub section is more specifically characterized in this embodiment. In this case, one of the features of the embodiment according to the present invention is composed of the relevant curved portion having a maximum value (with respect to the angle) in the region of 40% - 50% of the length between the inlet surface and the outlet surface. The turbine wheel according to the prior art typically does not have a maximum value or continuously decrease over the entire length of the region with respect to the angle.

[0018] According to a further embodiment of the present invention, the angle of the curved portion located between the curved portion at the transition portion and the curved portion at the outer edge has a maximum value that is not so prominent compared to the maximum value. In this case, the angle of the relevant curved portion can have its respective maximum value in the region of 20% - 40% of the length. The maximum values of adjacent curved portions can transition to a plateau in the direction of the outer edge.

[0019] This embodiment is based on the relevant curvature between the hub section and the outer section, i.e., the curvature that is located as a starting or ending point in a region of, for example, 25% to 75% of the length of the leading edge or trailing edge. Compared with the curvature of the hub section, a maximum value is also formed in this case, but it is shown that it is not so prominent, i.e., the maximum angle of the maximum value has a lower value. Further, the maximum value is also shifted towards a smaller length value or, in the case of a more outwardly located curvature (e.g., when a starting point is given for a curvature at 75% of the leading edge), gradually transitions to a plateau.

[0020] In another variant, the angle of the curvature located between the curvature at the transition and the curvature at the outer edge can each have a maximum value in the form of a plateau.

[0021] Instead of the embodiment with the maximum value described above, the curvature between the hub section and the outer section can also be formed without distinguishable extreme values, so that in each case, the maximum value is in the form of a plateau.

[0022] According to a further embodiment of the present invention, the angle of the relevant curvature is maintained constant or approximately constant along the outer edge of the blade in a region up to 20% of the length, and then decreases to form a maximum value in the shape of a plateau.

[0023] The so-called outer section, i.e., the curvature in the region of the outer edge of the blade, is described in more detail in this embodiment. Usually, instead of the embodiment with extreme values, the maximum value in this case is designed to be a plateau up to about 20% of the length and then decrease.

[0024] In this case, the angle of the relevant curvature along the outer edge of the blade can have a maximum value in a region of less than 5% of the length.

[0025] However, in other variations, embodiments are contemplated where the angle along the outer wheel has an extreme value that typically forms a maximum value at a very short length of a few percent of the length. However, this maximum value typically measures only a few degrees.

[0026] According to the present invention, there is provided a variable turbine geometry for use in an internal combustion engine Turbocharger comprising Turbocharger a bearing housing on a shaft, a compressor wheel, and a turbine wheel driving the compressor wheel in an arrangement having a variable turbine geometry, the turbine wheel including a plurality of blades on a hub forming a rear wall, adjacent blades having an inlet surface with two leading edges and an outlet surface having two trailing edges and being located substantially axially inward, and the surface of the blade being configurable by the angles and lengths of a plurality of curved portions located adjacent to each other between the leading edge and the trailing edge, and in each of the curved portions, the angle of the leading edge first increases or is maintained constant and then decreases to form a maximum value as the length increases Turbocharger is provided.

[0027] The characteristic arrangement of the turbine wheel enables the gas flowing through the turbine wheel within to be accelerated in a relatively delayed manner, Turbocharger by the reduced moment of inertia inside the turbine wheel and by the improvement in the level of thermodynamic efficiency Turbocharger to increase the efficiency of

Brief Description of the Drawings

[0028] Some exemplary embodiments will now be described in more detail with reference to the drawings. Shown are:

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 5C

Figure 5D

Figure 5E

DETAILED DESCRIPTION OF THE INVENTION

[0029] In the drawings, the same or functionally identical components are provided with the same reference numerals.

[0030] First, an embodiment of the turbine wheel according to the present invention can preferably be used Turbocharger 1 is schematically described below with reference to FIG. 1. In this context, FIG. 1 can show the positions of the individual components simply so that Turbocharger 1 shows a schematically sketched cross-sectional view. This type of Turbocharger 1 is known per se from the prior art.

[0031] FIG. 1 shows a cross-section of a partial perspective view of 1 according to the present invention. Turbocharger 1 shows a cross-section of a partial perspective view of 1 according to the present invention. Turbocharger1 includes a turbine housing 2 and a compressor housing 3 connected to the turbine housing 2 via a bearing housing 4. The turbine housing 2, the compressor housing 3, and the bearing housing 4 are arranged along the axis Z. The turbine housing 2 is shown in partial cross-section. In this case, a shaft 5 connects the turbine wheel 10 to the compressor wheel 6. On the turbine side, a variable turbine geometry system is arranged by means of a vane bearing ring 7, which includes a plurality of adjustable vanes 8 having corresponding axes of rotation and distributed along the circumference. Thereby, a nozzle cross-section is formed, which becomes larger or smaller depending on the position of the adjustable vanes 8, and the engine exhaust gas supplied via the supply channel 11 and discharged to the turbine located at the center of the axis Z via the central nozzle is applied to a greater or lesser extent to drive the compressor wheel 6 via the turbine wheel 10. In order to control the movement, or rather the position, of the adjustable vanes 8, operating means or an actuator, which can be designed, for example, as an electric actuator or a pneumatic actuator, is provided. The operating means can set an adjustment ring 9 located behind the vane bearing ring 7 to a slight rotational movement.

[0032] As schematically shown in FIG. 1 Turbocharger 1, for use in an internal combustion engine, obviously includes further components. This type of Turbocharger 1 is called a VTG turbocharger. Turbocharger An embodiment of the turbine wheel 10 according to the invention that can be used in 1 will be described in more detail below.

[0033] A perspective side view of the turbine wheel 10 is shown in FIG. 2. It is clear that the turbine wheel 10 preferably includes blades 12 arranged on a hub 16 that are equidistantly spaced and form a rear wall 14. Between adjacent blades 12, an inlet surface 18 adjacent to two leading edges 20 is formed. In this case, the inlet surface 18 is arranged on the circumferential side of the radially outer side. Also, an outlet surface 22 is provided, which is formed between two trailing edges 24 of adjacent blades 12 and is located substantially axially inward.

[0034] As a result, the gas flows into the turbine wheel 10 from the inlet surface 18 to the outlet surface 22, and the surface 26 of the blade 12 is selected such that the gas can be accelerated between the inlet surface 18 and the outlet surface 22. As a result, the turbine wheel 10 is set in a slight rotational movement called the rotational direction R in FIG. 2. The region of the blade 12 defined by the rear wall 14 that crosses the leading edge 20 and the trailing edge 24 towards the end of the hub 16 is referred to as the outer edge 28 in the following embodiments.

[0035] According to the present invention, the embodiment of the surface 26 of the blade 12 is selected such that further improvements are achieved with respect to the degree of mass inertia and thermodynamic efficiency compared to turbine wheels from the prior art. In this case, the description of the embodiment according to the present invention can be carried out in various ways. On the one hand, an attempt can be made to show the meridional progression between the inlet surface 18 and the outlet surface 22 with respect to the thermodynamically active surface so that the acceleration of the gas can be explained. However, the advantageous effects of the embodiment of the turbine wheel 10 according to the present invention can simply experience difficulties because other thermodynamic conditions can occur depending on the existing pressure conditions or rotational speeds.

[0036] As a result, another approach was selected with reference to FIG. 3. The turbine 10 is associated with a stationary coordinate system, and in this case, a representation similar to the polar coordinate system is selected. In this context, the angle T is selected to increase in the rotational direction R, while various starting values along the leading edge 20 are selected to describe the contour. The angle T is set to zero at each of these starting points along the leading edge 20 in each case. In some applied cases, the metal angle is also derived from the angle T, thus making it possible to determine the contextual relationship with the surface contour of the blade 12 regardless of the actually existing thermodynamic conditions.

[0037] For the sake of completeness, it should also be mentioned that the contour of the blade 12 on the surface 26 is not precisely embodied. It has been proven advantageous to select the blade center as a reference plane. The blade center is also referred to as the center of the suction side and the pressure side.

[0038] The contour line along the blade 12 towards the axis of rotation is hereinafter referred to as direction Z. In each case, since the lengths of the various contour lines can result depending on the starting point on the leading edge 20 or the ending point on the trailing edge 24, this line is normalized. This kind of representation is common in the field of turbine wheels, and in this context, it must be mentioned that the above-mentioned US literature adopts a similar approach.

[0039] Next, FIG. 4 shows a side view of the turbine wheel 10, in which case the various contour lines are shown as curvatures 30, 32, 34, 36, and 38. In this case, the first curvature 30 is selected at the transition between the blade 12 and the hub 16. Thereby, the additional curvatures 32, 34, and 36 are spaced equidistantly, and in this case, the more inwardly located starting and ending points are selected along the leading edge 20 or the trailing edge 24. In this case, the fifth curvature 38 is along the outer edge 28 of the blade 12. The contour of the blade 12 can be described using the shown group of curvatures 30, 32, 34, 36, and 38. It must be mentioned again at this point that the shown curvatures 30 - 38 are typically shown at the center of the blade.

[0040] Next, the progression of the angle T across the normalized Z-direction Z0 is shown in FIGS. 5A - 5E as the curvature for each of the above-described curvatures 30 - 38. The curvature shown using the dashed line corresponds, in this case, to the contour of the surface achieved from the prior art using a turbine wheel. Thus, determining the parameter of the angle T along the direction Z0 is done in the same manner, and a further turbine wheel 10' is shown in FIG. 4 for comparison with the blade shape. The latter is shown (from rear wall to rear wall) so as to be immediately adjacent to the turbine wheel 10 according to the present invention for comparison. Since the comparative example does not have a maximum value for the above-described curvature, it follows the same course as that shown in FIGS. 5A - 5E by the curvature shown using the dashed line. The shape of the leading edge 20' of the turbine wheel 10' according to FIG. 4 is significantly different.

[0041] In the region of the transition between the blade 12 and the hub 16, the angle T of the leading edge 20 first increases as the length Z0 of the curvature 30 increases as shown in FIG. 5A initially, forming a maximum value 40. The degree of the angle T then decreases as the length Z0 subsequently decreases.

[0042] According to the figures shown in FIGS. 5B - 5D, a maximum value 40' is similarly formed for the curvatures 32, 34, and 36 that are further separated from the transition between the blade 12 and the hub 16. In this case, this maximum value is either not as prominent for the curvature located closer to the outer edge 28 or rather is shifted towards a smaller length value Z0.

[0043] For the last curvature 38 shown in FIG. 5E, only a kind of plateau 40″ is formed. As a result, the angle T first remains constant and then decreases as the length Z0 increases. In this description, the term "plateau" is not to be understood as simply meaning an exactly horizontal course for the angle T, since a deviation of several degrees from the angle T can also occur.

[0044] In this case, the maximum value 40 for the first curved portion 30 is formed in a region of 40% to 50% of the length Z0. The maximum values 40' for the curved portions 32, 34, and 36 are typically located in a region of 20% to 40% of the length Z0. However, in other embodiments, the progression with a plateau (as shown in FIG. 5E in connection with the curved portion 38) actually exists for all of the curved portions 32, 34, and 36 as well as not only the curved portion 36 or the curved portions 34 and 36.

[0045] The arrangement according to the invention of the blade 12 can reduce the mass inertia of the turbine wheel 10 because its shape is determined by a relatively delayed acceleration of the gas flow in relation to the meridian trajectory of said flow. Turbocharger The use of the turbine wheel 10 according to the invention in 1 results in a faster acceleration during the start-up of the internal combustion engine because it reduces the mass inertia of the latter. As a result, Turbocharger The level of the thermodynamic efficiency of the turbine wheel 10 according to the invention in 1 is also improved and can be improved, in particular, during the interaction with additional components in an arrangement having a variable turbine geometry.

[0046] Not only the features defined above and in the claims, but also the features that can be gathered from the drawings can be embodied in an advantageous manner both individually and in various combinations. The invention is not limited to the described embodiments, but rather can be modified in many ways within the scope of the expertise of those skilled in the art.

[0047] Explanation of reference signs 1 Turbocharger 2 Turbine housing 3 Compressor housing 4 Bearing housing 5 Shaft 6 Compressor wheel 7 Vane bearing ring 8 Adjustable vane 9 Adjusting ring 10, 10' Turbine wheel 11 Supply channel 12 Blade 14 Rear wall 16 Hub 18 Inlet surface 20, 20' Leading edge 22 Outlet surface 24 Trailing edge 26 Surface 28 Outer edge 30 - 38 Curved portion 40 Maximum value 40' Maximum value 40'' Maximum value

Claims

1. A turbine wheel (10) for a turbocharger for use in an internal combustion engine, including a plurality of blades (12) on a hub (16) forming a rear wall (14), wherein adjacent blades among the plurality of blades have an inlet surface (18) between two leading edges (20) on the radially outer side of the turbine wheel and an outlet surface (22) between two trailing edges (24) and located axially outward of the turbine wheel relative to the inlet surface, the shape of the surface (26) of the blade is constituted by a plurality of curved portions (30,..., 38) formed adjacent to each other between the leading edge and the trailing edge, and the angle (T) and length (Z0) in the rotational direction of the turbine wheel of each of the plurality of curved portions, each curved portion being a contour line of the blade surface starting from the leading edge and ending at the trailing edge, and the shape of the blade surface being defined by a plurality of the contour lines, the angle (T) is formed as a polar angle, the angle of each curved portion is set to a zero point at the starting point, and the angle increases from the zero point when the angle is directed in the rotational direction with respect to the starting point, in each of the curved portions (30,..., 38), as the length (Z0) of each curved portion increases from the starting point to the ending point, the angle (T) first increases with respect to the zero point and then decreases or is maintained constant and then decreases, and a maximum value (40, 40', 40") is determined, the turbine wheel.

2. The turbine wheel according to claim 1, wherein each of the plurality of curved portions (30,..., 38) is set in order from the transition portion between the blade (12) and the hub (16) to the outer edge (28) between the leading edge and the trailing edge in the blade.

3. The turbine wheel according to claim 2, wherein the contour lines forming each of the plurality of curved portions (30,..., 38) are set to be equidistant from each other.

4. The turbine wheel according to claim 2, wherein the angle (T) of the first curved portion (30) on the transition portion side among the plurality of curved portions first increases as the length (Z0) increases and has a maximum value (40) of the angle in a region of 40% to 50% of the total length of the length, and then decreases as the length (Z0) further increases.

5. Among the plurality of curved portions, the angle (T) of the third curved portion (32, 34, 36) located between the first curved portion (30) and the second curved portion (38) on the outer edge side has a maximum value (40') smaller than the maximum value (40). The turbine wheel according to claim 4.

6. The angle (T) of the third curved portion (32, 34, 36) has its respective maximum value (40') in a region of 20% to 50% of the length (Z0). The turbine wheel according to claim 5.

7. Each of the third curved portions (32, 34, 36) is configured such that after showing the maximum value (40'), the angle with respect to the length is substantially constant along the outer edge (28). The turbine wheel according to claim 5 or 6.

8. The angle (T) of each of the third curved portions (32, 34, 36) has a maximum value in a form that is substantially constant. The turbine wheel according to claim 5 or 6.

9. The angle (T) of the second curved portion (38) forms a maximum value (40'') that is maintained constant or substantially constant along the outer edge (28) of the blade (12) in a region up to 20% of the length (Z0), and then decreases. The turbine wheel according to claim 5.

10. The angle (T) of the second curved portion (38) along the outer edge (28) of the blade (12) has a maximum value (40'') in a region less than 5% of the length (Z0). The turbine wheel according to claim 9.

11. A turbocharger having a variable turbine geometry for use in an internal combustion engine, including a bearing housing (4) on a shaft (5), a compressor wheel (6), and an array having a variable turbine shape, driving the compressor wheel (6). The turbocharger includes the turbine wheel (10) according to any one of claims 1 to 10.

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