Adjustment mechanism for a turbocharger flow section

Abstract

The invention relates to an adjustment mechanism for a flow section of a turbocharger for adjusting a variable flow cross-section for an air flow in the turbocharger. The adjustment mechanism has a plurality of guide vanes which define the flow cross-section by their arrangement and are arranged in such a movable manner that a blade movement of the guide vanes causes a variation in the flow cross-section, an adjustment element (1) which is movably arranged and mechanically coupled to the plurality of guide vanes in such a way that an adjustment movement of the adjustment element (1) causes the blade movement of the guide vanes, an actuator (2) for generating the adjustment movement of the adjustment element (1) and thereby generating the blade movement of the guide blades to vary the flow cross-section, and a brush seal (3) which is arranged between the adjustment element (1) and the actuator (2) in such a way as to protect the actuator from contamination.

Description

[0001] Aty Docket: GAR GOO 1463 IA

[0002] ADJUSTMENT MECHANISM FOR TURBOCHARGERS

[0003] Description:

[0004] The invention relates to an adjustment mechanism for a flow section of a turbocharger for adjusting a variable flow cross-section for an air flow in the turbocharger.

[0005] Turbochargers are used in internal combustion engines to increase engine power by increasing the air pressure in the intake tract, resulting in improved fuel efficiency and higher power output. Variable inlet compressors are an essential component for the efficient operation of a turbocharger, as they enable dynamic adjustment of the air flow into the compressor depending on the operating conditions of the engine. This dynamic control optimizes engine performance across a wide range of speeds and loads.

[0006] In modem turbochargers, air intake variability is typically achieved by a series of guide vanes arranged in a ring shape within the compressor. These guide vanes are adjustable and allow precise regulation of the airflow to match the desired operating parameters of the engine. The blade angles are adjusted by means of an adjustment element, usually via an adjustment ring mechanism that coordinates the simultaneous movement of several blades. The adjustment ring itself is driven by a mechanical or electrical actuator that generates a rotational movement of the adjustment ring via an actuating element. The rotational movement of the adjustment ring leads to a synchronized change in the blade angles, thereby regulating the air flow into the compressor accordingly. Such an adjustment mechanism is disclosed, for example, in EP 3 647 601 Bl.

[0007] To ensure the long-term functionality of this adjustment mechanism, especially in the demanding environment of a turbocharger, it is crucial to protect the actuator and other critical components. In existing designs, two main seals are typically used to protect the actuator and the actuating element. First, an O-ring is placed immediately in front of the actuator to protect it from contaminants such as dirt and oil. This seal ensures that no foreign objects can enter the actuator and interfere with its operation. Second, a slide seal, in this case an X-ring seal, is Aty Docket: GAR GOO 1463 IA placed around the actuating element, which connects the actuator to the adjustment ring. The slide seal prevents dirt and oil from leaving the actuating element area toward the actuator.

[0008] Although this arrangement is widely used in turbocharger systems, it has several fundamental weaknesses, particularly with regard to the sliding seal. The sliding seal around the actuating element must allow the translational movement of the actuating element, as this translational movement causes the rotational movement of the adjustment ring. However, since the actuator is constantly moving, lubrication is required to minimize friction between the slide seal and the bore or cavity in which the actuator moves and to reduce wear. Although lubrication of the slide seal is effective initially, it tends to lose its effectiveness over time due to heat and contact with contaminants. This causes the slide seal to wear and impairs its sealing function, which can ultimately lead to failure of the entire turbocharger system.

[0009] In addition, the movement of the slide seal within the bore causes additional abrasion. This abrasive interaction between the slide seal and the bore accelerates wear on the slide seal over time and impairs its sealing function. Once the sliding seal is worn out, dirt, oil, and other contaminants, especially abrasive material, can enter the actuator mechanism, which can lead to failure of the entire adjustment mechanism. Another disadvantage of the sliding seal is that it creates a hermetic seal, which can lead to air compression when the actuator moves. The actuator must work against this air compression, which leads to faster wear of the actuator.

[0010] The object of the invention is to provide an adjustment mechanism for a turbocharger that is less prone to failure and therefore more durable.

[0011] According to the invention, the task is solved by an adjustment mechanism with the features of claim 1, by a turbocharger with the features of claim 12, and by a vehicle with the features of claim 13. Advantageous further developments of the invention are listed in the subclaims.

[0012] According to one aspect of the invention, an adjustment mechanism for a flow section of a turbocharger is proposed for adjusting a variable flow cross-section for an air flow in the turbocharger. There are several air flows within a turbocharger. For some of these air flows, it is advantageous to guide them through a variable and controllable flow cross-section in order Aty Docket: GAR GOO 1463 IA to increase the efficiency of the turbocharger. For this purpose, the adjustment mechanism has several guide vanes which define the flow cross-section by their arrangement. In addition, the guide vanes are movably arranged in such a way that a blade movement of the guide vanes causes a variation in the flow cross-section. If a smaller flow cross-section is required, the blade movement moves the guide vanes into a position in which they restrict the flow cross-section accordingly. If a larger flow cross-section is then required, the guide vanes are moved by means of the vane movement into another position which corresponds to the larger flow cross-section.

[0013] In order to effect the blade movement of the guide blades, an adjustment element is provided which is movably arranged and mechanically coupled to the plurality of guide blades in such a way that an adjustment movement of the adjustment element effects the blade movement of the guide blades. For example, the adjustment movement may be a rotating movement, in particular a rotating swivel movement. This is the case, for example, if the adjustment element is an adjustment ring, such as in particular the adjustment ring described at the beginning.

[0014] The adjustment movement of the adjustment element is in turn generated by means of an actuator. The actuator can be electrically or hydraulically driven, for example, or by another suitable type of drive. The actuator acts on the adjustment element in such a way that the adjustment element performs the adjustment movement. The adjustment element in turn acts on the guide vanes in such a way that they perform the blade movement. Due to the blade movement, the guide vanes are moved into a suitable position in order to set a necessary or desired flow cross-section. The position also includes a desired spatial orientation of the guide vanes.

[0015] Instead of a sliding seal separating the adjustment element from the actuator, the invention provides for a brush seal to be arranged between the adjustment element and the actuator. This brush seal serves to protect the actuator from contamination. A brush seal has flexible bristles that are arranged more or less close together. The bristles are attached around an opening located between the adjustment element and the actuator. These bristles can adapt to uneven surfaces and minimize the gap through which dust, dirt, or liquids could penetrate. In the present application , the brush seal adapts to moving elements in the interaction between the actuator and the adjustment element due to the flexible bristles. This means that the bristles Aty Docket: GAR GOO 1463 IA move around the moving elements and maintain the sealing effect of the brush seal, in particular without creating a hermetic seal.

[0016] Preferably, the adjustment mechanism is designed to adjust a variable inlet cross-section for an inlet flow section of a compressor wheel of the turbocharger. In this case, the multiple guide vanes define the inlet cross-section by their arrangement. Furthermore, the blade movement of the guide vanes causes a variation in the inlet cross-section. In this case, the guide vanes are used in particular to vary the inlet cross-section for an axial air flow.

[0017] Alternatively, the adjustment mechanism can be designed to adjust a variable diffuser crosssection for a diffuser of the turbocharger. In this case, the multiple guide vanes define the diffuser cross-section by their arrangement, whereby the blade movement of the guide vanes causes the diffuser cross-section to vary. In this case, the guide vanes are used in particular to vary the cross-section for radial air flow.

[0018] According to a preferred further development, the guide vanes are arranged to be pivotable so that the blade movement is a pivoting movement of the blades. In particular, the guide vanes can each be pivotably suspended at one guide vane end.

[0019] In a practical embodiment, the guide vanes are arranged to define a flow diameter for axial air flow. The flow cross-section defined by the guide vanes is preferably oval or circular. In this case, the guide vanes are arranged in such a way that a blade movement of the guide vanes causes a variation in the flow diameter.

[0020] In an advantageous further development, the adjustment element is designed to be ring-shaped and surrounds the flow cross-section in a ring shape. The adjustment element is in particular an adjustment ring which is mechanically connected to each of the guide vanes. The adjustment movement of the ring-shaped adjustment element is then a rotational movement or a rotating swivel movement which causes the blade movement.

[0021] Preferably, the brush seal is arranged in a flow path between the adjustment element and the actuator. In other words, the brush seal is located within a cavity that extends within the Aty Docket: GAR GOO 1463 IA adjustment mechanism between the adjustment element and the actuator. By being arranged within this cavity, the brush seal can obstruct and collect contamination particles that could penetrate along the flow path to the actuator. Preferably, the brush seal is arranged in the flow path in such a way that the flow path is completely closed by the brush seal, so that media exchange between the adjustment element and the actuator via the flow path can only take place through the brush seal.

[0022] According to an advantageous design, the brush seal is arranged in a frame that surrounds the flow path. The brush seal can be firmly glued into the frame to ensure secure fastening.

[0023] Alternatively, the brush seal can be detachably fastened to a holder arranged in the flow path. This allows the brush seal to be replaced, for example, during device maintenance. Such a detachable fastening is possible, for example, by means of screws or a clamp connection.

[0024] In a preferred embodiment, the actuator acts on an actuating section of the adjustment element to generate the adjustment movement of the adjustment element. In particular, the actuating section may protrude from the adjustment element and penetrate a brush plane along which the bristles of the brush seal are oriented. For example, the actuating section may protrude from the adjustment element in the form of a pin, in particular protruding radially. Preferably, the actuating section is integrally molded onto the adjustment element.

[0025] In a preferred embodiment, the actuating section of the adjustment element is surrounded by the brush seal. The actuating section is preferably the only component surrounded by the bristles of the brush seal.

[0026] In a practical embodiment, the actuator acts on the adjustment element or on the actuating section of the adjustment element by means of an actuating element in order to generate the adjustment movement of the adjustment element. The actuating element may, for example, be a cylindrical element. The actuating element preferably performs a translational movement.

[0027] A major problem with the state-of-the-art sliding seal described in the introduction is that it forms a hermetic seal around the actuating element during the movement of the actuating Aty Docket: GAR GOO 1463 IA element. Air cannot flow from one side of the sliding seal to the other, or can only do so with difficulty. This results in air compression in the cavity. The actuator must then exert additional power to move the actuating element. This places additional strain on the actuator and leads to accelerated wear of the actuator, which significantly shortens its service life.

[0028] According to a preferred further development, it is therefore provided that the actuating element is movably arranged in a cavity which is open in terms of flow. In other words, the cavity, preferably a cavity in a housing of the turbocharger, is not divided into hermetically separated areas. This means that no air compression takes place when the actuating element is moved.

[0029] Preferably, the bristles of the brush seal are made of metal, metal alloys, and / or a polymer. Other suitable materials can also be used, for example, carbon, in other words, carbon bristles.

[0030] In a turbocharger, the adjustment mechanism may be designed in accordance with one of the embodiments described herein to adjust a variable inlet cross-section for an inlet flow section of a compressor wheel of the turbocharger. Alternatively, the adjustment mechanism may be designed to adjust a variable diffuser cross-section for a diffuser of the turbocharger. Alternatively, two such adjustment mechanisms may also be implemented in the same turbocharger, i.e., a first adjustment mechanism for adjusting the variable inlet cross-section for an inlet flow section of a compressor wheel of the turbocharger and a second adjustment mechanism for adjusting a variable diffuser cross-section for the diffuser of the turbocharger. The first and second adjustment mechanisms may be designed individually or both may be designed in accordance with one of the embodiments described above or below.

[0031] The invention is explained below with reference to the figures using embodiments. Here,

[0032] Fig. la schematic cross-sectional view of an adjustment mechanism for adjusting a variable flow cross-section for an air flow in a turbocharger according to the prior art;

[0033] Fig. 2a schematic cross-sectional view of an adjustment mechanism for adjusting a variable flow cross-section for an air flow in a turbocharger according to a preferred embodiment; Aty Docket: GAR GOO 1463 IA

[0034] Fig. 3a further cross-sectional view of the adjustment mechanism shown in Fig. 2 along a second sectional plane; and

[0035] Fig. 4shows another cross-sectional view of the adjustment mechanism shown in Fig. 2 along a third sectional plane.

[0036] Fig. 1 shows a schematic cross-sectional view of an adjustment mechanism according to the prior art. In particular, this is the adjustment mechanism for an inlet flow section for a compressor wheel. Only the adjustment element 1, the actuating element 4, and the actuator 2 of the adjustment mechanism are shown in Fig. 1. The guide vanes, which define the flow cross-section, are not shown in the figures. They are mechanically connected to the adjustment element 1, distributed along its radius, in such a way that an adjustment movement of the adjustment element 1 causes a blade movement of the guide vanes, thereby varying the flow cross-section.

[0037] The adjustment movement is a rotational movement or a rotating swivel movement of the adjustment element 1, which is designed as an adjustment ring. A pin-shaped actuating section 12 is integrally molded onto the adjustment element 1, which engages with the actuating element 4. The actuating element 4, in turn, is moved by means of the actuator 2. The movement of the actuating element 4 leads to the rocking movement of the adjustment element 1 via the coupling with the actuating section 12. The actuating element 4 is arranged in a cavity of a housing 5 of the turbocharger. In order to protect the actuator 2 from contamination arising in the area of the inlet flow or the adjusting element 1, a sliding seal 43 is provided, which is usually designed as an X-ring seal. The sliding seal 43 divides the cavity into a first cavity 52 and a second cavity 53, whereby the sliding seal 43 provides a hermetic separation between the two cavities 52, 53. Finally, a further seal is provided to protect the actuator 2, namely an actuator seal 23, which is arranged statically between the actuator 2 and the housing 5 and may consist, for example, of an O-ring.

[0038] In the design of the adjustment mechanism according to the invention, which is shown in Figs. 2-4, a brush seal 3 is used instead of the sliding seal 43 to protect the actuator 2 from contamination. The brush seal 3 is arranged in a passage area of the housing 5, which forms a passage for the actuating section 12 of the adjustment element 1. Fig. 3 shows this design Aty Docket: GAR GOO 1463 IA according to the invention in the same view as the prior art in Fig. 1. The brush seal 3 surrounds the actuating section 12 of the adjustment element 1 and can thus prevent contamination from entering the cavity 51. Due to the elimination of the sliding seal 43, the cavity 51 is not divided into hermetically sealed parts. Instead, the cavity 51, in which the actuating element 4 moves back and forth, is open in terms of flow, so that no air compression occurs there due to the movement, which the actuator would have to counteract.

[0039] As shown in the further cross-sectional view in Fig. 3, the brush seal 3 may be formed from an upper brush row 31 and a lower brush row 32, which surround the actuating section 12 from two sides. The actuating section 12 can move with low friction between these brush rows 31, 32. The bristles of the brush seal 3 slide around the actuating section 12 to fill areas exposed during movement. Another cross-sectional view, this time as a sectional view through the actuating section 12 and the actuating element 4, is shown in Fig. 4. Here it can be seen that the actuating section 12 of the adjustment element 1 protrudes through the two brush rows 31, 32 and engages in a recess of the actuating element 4, which moves in the cavity 51.

[0040] As shown schematically in Figs. 3 and 4, the brush seal consisting of the brush rows 31, 32 is arranged in a frame 35 or in a holder 35. The frame 35 or holder surrounds or encloses a flow path in the housing 5 that opens into the cavity 51. For example, the brush rows 31, 32 can be screwed into the holder to form a detachable connection.

[0041] Aty Docket: GAR GOO 1463 IA

[0042] List of reference symbols:

[0043] 1 Adjustment element, adjustment ring

[0044] 12 Actuating section

[0045] 2 Actuator

[0046] 23 Static actuator seal

[0047] 3 Brush seal

[0048] 31 Upper brush row

[0049] 32 Lower row of brushes

[0050] 35 Frame, bracket

[0051] 4 Actuating element

[0052] 43 Sliding seal

[0053] 5 Housing

[0054] 51 Cavity

[0055] 52 First cavity

[0056] 53 Second cavity

Claims

Aty Docket: GAR GOO 1463 IAClaims:

1. Adjustment mechanism for a flow section of a turbocharger for adjusting a variable flow cross-section for an air flow in the turbocharger, comprising: a plurality of guide vanes which define the flow cross-section by their arrangement and are arranged in such a way that movement of the guide vanes causes the flow cross-section to vary; an adjustment element (1) which is movably arranged and mechanically coupled to the plurality of guide vanes in such a way that an adjustment movement of the adjustment element(1) causes the blade movement of the guide vanes; and an actuator (2) for generating the adjustment movement of the adjustment element (1) and thereby generating the blade movement of the guide blades to vary the flow cross-section, characterized by a brush seal (3) arranged between the adjustment element (1) and the actuator(2) in such a way as to protect the actuator from contamination.

2. Adjustment mechanism according to claim 1, characterized in that the brush seal (3) is arranged in a flow path between the adjustment element (1) and the actuator (2).

3. Adjustment mechanism according to claim 2, characterized in that the brush seal (3) is arranged in a frame which surrounds the flow path.

4. Adjustment mechanism according to claim 2 or 3, characterized in that the brush seal (3) is detachably fastened to a holder arranged in the flow path.

5. Adjustment mechanism according to one of the preceding claims, characterized in that the actuator (2) acts on an actuating section (12) of the adjustment element (1) in order to generate the adjustment movement of the adjustment element (1).

6. Adjustment mechanism according to claim 5, characterized in that the actuating section (12) protrudes from the adjustment element and penetrates a brush plane along which the bristles of the brush seal are oriented.Aty Docket: GAR GOO 1463 IA7. Adjustment mechanism according to claim 5 or 6, characterized in that the actuating section (12) of the adjustment element (1) is surrounded by the brush seal.

8. Adjustment mechanism according to one of the preceding claims, characterized in that the actuator (2) acts on the adjustment element (1) or on the actuating section () of the adjustment element (1) by means of an actuating element (4) in order to generate the adjustment movement of the adjustment element (1).

9. Adjustment mechanism according to one of the preceding claims, characterized in that the actuating element (4) is movably arranged in a cavity (51) which is open in terms of flow.

10. Adjustment mechanism according to one of the preceding claims, characterized in that the bristles of the brush seal (3) are made of metal, a metal alloy, a polymer, and / or carbon bristles.

11. Adjustment mechanism according to one of the preceding claims, designed to adjust a variable inlet cross-section for an inlet flow section of a compressor wheel of the turbocharger, wherein the plurality of guide vanes define the inlet cross-section by their arrangement and the blade movement of the guide vanes causes a variation in the inlet crosssection, or a variable diffuser cross-section for a diffuser of the turbocharger, wherein the plurality of guide vanes define the diffuser cross-section by their arrangement and the blade movement of the guide vanes causes the diffuser cross-section to vary.

12. Adjustment mechanism according to one of the preceding claims, characterized in that the guide vanes are arranged to be pivotable so that the blade movement is a pivoting movement of the blades.

13. Adjustment mechanism according to one of the preceding claims, characterized in that the guide vanes define a flow diameter for an axial air flow by their arrangement and are arranged to be movable in such a way that a blade movement of the guide vanes causes a variation in the flow diameter.Aty Docket: GAR GOO 1463 IA14. Adjustment mechanism according to one of the preceding claims, characterized in that the adjustment element (1) is designed to be ring-shaped and surrounds the flow cross-section in a ring shape.

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