Control device of an exhaust gas guide section of an exhaust gas turbocharger

Abstract

The invention relates to a control device (8) of an exhaust gas guide section (1) of an exhaust gas turbocharger (2), wherein the control device (8) has a closure device (9) comprising a closure element (10) and an element lever (11), wherein the closure device (9) can be swivelled about an axis of rotation (19), and wherein the closure element (10) is designed for opening and closing a first flow cross-section (13) of the exhaust gas guide section (1), wherein the first flow cross-section (13) is formed in a separating wall lying between a first spiral channel (4) of the exhaust gas guide section (1) and a second spiral channel (5) of the exhaust gas guide section (1), and wherein the exhaust gas guide section (1) has a second flow cross-section (17) which is assigned a bypass channel (18) formed in the exhaust gas guide section (1), which is designed for bypassing an impingement of a turbine wheel formed in the exhaust gas guide section (1), and wherein the closure element (10) has a first element section (15) for closing the first flow cross-section (13) and a second element section (16), which can be used for closing the second flow cross-section (17), and wherein the element lever (11) has an arm section (21) designed for engaging into a hollow space (20) of the closure element (10), and wherein the hollow space (20) has an inner surface (23) and the arm section (21) has an outer surface (24) formed opposite the inner surface (23). According to the invention, an inner casing surface (44) of the inner surface (23) and a casing surface (31) of the outer surface (24) are identical in shape while having different dimensions, wherein the casing surface (31) has at least two different casing sections (32, 33).

Description

[0001] Control device of an exhaust gas guide section of an exhaust gas turbocharger

[0002] The invention relates to a control device of an exhaust gas guide section of an exhaust gas turbocharger of the type specified in the preamble of patent claim 1.

[0003] Exhaust gas guide sections for exhaust gas turbochargers, which have a control device for controlling a fluid flowing through the exhaust gas guide section, generally exhaust gas, are known. The control device is provided for opening and closing a bypass channel in the flow-through exhaust gas guide section to bypass a turbine wheel of the exhaust gas guide section, which is rotatably arranged in a wheel chamber of the exhaust gas guide section. Furthermore, the control device can open or close a flow opening formed between two spiral channels of the exhaust gas guide section, allowing the exhaust gas to flow from one spiral channel to the other and vice versa.

[0004] With the aid of such a control device, it is possible to completely or partially bypass the turbine wheel at certain operating points of the exhaust gas turbocharger, particularly at operating points involving large flow rates, thus enabling efficient operation of the exhaust gas turbocharger. The efficient operation of the exhaust gas turbocharger depends on a specific opening characteristic of the control device, which must be adapted to the requirements of a drive unit connected to the exhaust gas turbocharger, particularly an internal combustion engine.

[0005] The control device has a plurality of components which are connected to one another, whereby relative movements of individual components to one another are also possible. For example, a closing element of the control device, which is provided for closing the bypass channel and / or the flow opening, has a possible mobility relative to a lever arm of the control device which is designed to move the closing element and which receives the closing element at one end. This possible mobility is necessary so that jamming in the exhaust gas guide section can be avoided, for example when the lever arm is pivoted with the closing element. The relative mobility of the two components to one another causes wear on the control device during operation of the exhaust gas turbocharger, which wear must at least be reduced.

[0006] For example, published patent application DE 10 2017 202 132 A1 discloses a control device for an exhaust gas turbocharger, which has a closing element mounted on a lever arm of the control device. The lever arm is designed to protrude into a cavity of the closing element. To reduce wear, one end of the lever arm, which protrudes into the cavity, is designed in sections to bring about contact with the closing element. For this purpose, the end of the lever arm has guide elements with guide surfaces that can come into contact with the closing element.

[0007] The published patent application DE 10 2015 011 256 A1 also discloses a control device of an exhaust gas turbocharger, which has a closing element and a lever arm projecting into the closing element, wherein the end of the lever arm has a conical and a cylindrical guide element, which are designed to bring about a sliding contact.

[0008] The object of the present invention is to provide an improved control device of an exhaust gas guide section of an exhaust gas turbocharger.

[0009] This object is achieved according to the invention with a control device for an exhaust gas guide section of an exhaust gas turbocharger having the features of claim 1. Advantageous embodiments with expedient and non-trivial further developments of the invention are specified in the dependent claims. A control device according to the invention for an exhaust gas guide section of an exhaust gas turbocharger has a closing device comprising a closing element and an element lever, wherein the closing device is pivotable about a rotational axis. The closing element is designed to open and close a first flow cross-section of the exhaust gas guide section, wherein the first flow cross-section is formed in a partition wall located between a first spiral channel of the exhaust gas guide section and a second spiral channel of the exhaust gas guide section.The exhaust gas guide section has a second flow cross-section, which is assigned to a bypass channel formed in the exhaust gas guide section, which is designed to bypass the flow of a turbine wheel formed in the exhaust gas guide section. The closing element has a first element section for closing the first flow cross-section and a second element section which can be used to close the second flow cross-section. The element lever is designed to have an arm section designed to engage in a cavity of the closing element. The cavity has an inner surface, and the arm section has an outer surface opposite the inner surface. According to the invention, an inner circumferential surface of the inner surface and a circumferential surface of the outer surface are designed to be identical in shape but have different dimensions, wherein the circumferential surface has at least two different circumferential sections.

[0010] In principle, it is advantageous to implement a relative movement between the closing element and the element lever in order to prevent the closing element from tilting or jamming in the exhaust gas guide section. With the control device according to the invention, wear on the element lever and / or the closing element due to the relative movement is significantly reduced, since contact between the element lever, in particular the arm section, and the closing element can occur at various points on the arm section and the closing element. In other words, this means that, on the one hand, the contact between the arm section and the closing element, which is necessary for the reliable functioning of the control device, is present in every position of the control device, but can be made as large as necessary.Furthermore, noise generation is also reduced due to the size-optimized contact, which leads to size-optimized contact surfaces.

[0011] In one embodiment of the control device according to the invention, a movement gap is formed between the inner surface and the outer surface, which gap is configured depending on the position of the control device. This means that the inner surface and the outer surface can be configured depending on the operating points of a drive unit connected to the exhaust gas turbocharger.

[0012] In a further embodiment, the arm section is designed to be supported axially and / or radially on a cover element of the locking device so that it is securely received in the cavity of the locking element.

[0013] The inner surface and the lateral surface preferably have at least one frustoconical section.

[0014] In a further advantageous embodiment, the arm section is designed to extend along the longitudinal axis from its bottom surface, which is formed opposite a cavity bottom of the closing element, at least up to a closing surface of the second element section, so that a preferred tightness can be realized.

[0015] Particularly advantageous is a first transition section, which is formed between the first casing section and the second casing section, connecting the two casing sections to one another to ensure a continuous course of the casing surface along the longitudinal axis. This allows the arm section to slide unhindered on the closing element, with the first transition section also advantageously being curved. If the cavity floor has a groove at least at its bottom edge, which is formed adjacent to the first casing section, further improved sliding and thus a further reduction in wear can be achieved.

[0016] The arm section can alternatively be secured by means of a pin which is designed to extend from the cavity floor along the longitudinal axis.

[0017] Overall, it can be said that the control device according to the invention is designed to be wear-reduced even at high temperatures, and that heat transfer from the closing element to the element lever is reduced, which leads to lower component temperatures. Likewise, simple and cost-effective production, particularly in a casting process, is possible due to the simple contours of the closing element and the element lever, especially their contacting surfaces.

[0018] The pot-shaped design of the closing element and the arm section results in a weight-reduced control device.

[0019] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention. Identical or functionally equivalent elements are assigned identical reference numerals. They show: Fig. 1, in a perspective view, a section along a sectional plane through an exhaust gas guide section of an exhaust gas turbocharger with a control device according to the prior art,

[0020] Fig. 2 shows a perspective view of a closing device of a control device according to the invention of an exhaust gas turbocharger in a first embodiment,

[0021] Fig. 3 shows a section through the locking device. Fig. 2,

[0022] Fig. 4 shows a further section of the locking device. Fig. 2,

[0023] Fig. 5 shows a plan view of the locking device. Fig. 2,

[0024] Fig. 6 shows in a section the closing device of the control device according to the invention in a second embodiment,

[0025] Fig. 7 in a detailed view VII the locking device like Fig. 6,

[0026] Fig. 8 shows an exploded view of the control device according to the invention according to the second embodiment, and

[0027] Fig. 9 shows the control device according to the invention in a third embodiment.

[0028] A flow-through exhaust gas guide section 1 of an exhaust gas turbocharger 2 according to the invention, designed as shown in Fig. 1, comprises an inlet channel 3 for the entry of a fluid flow into the exhaust gas guide section 1, generally exhaust gas from an internal combustion engine 7, a first spiral channel 4 and a second spiral channel 5 downstream of the inlet channel 3 for conditioning the flow, and an outlet channel (not shown in detail) downstream of the spiral channels 4, 5, through which the exhaust gas can escape from the exhaust gas guide section 1 in a targeted manner. Between the spiral channels 4, 5 and the outlet channel, a wheel chamber (not shown in detail) is formed, in which a turbine wheel (not shown in detail) is rotatably received.

[0029] In the present exemplary embodiment, the exhaust gas guide section 1 is connected to an exhaust manifold 6 of the internal combustion engine 7, so that the exhaust gas of the internal combustion engine 7 can enter the spiral channels 4, 5 via the inlet channel 3 in order to act on the turbine wheel.

[0030] To adapt the operating behavior of the exhaust gas turbocharger 2 to the fluid flow of the internal combustion engine 7, and thus to the internal combustion engine 7, a control device 8 for separating and connecting the first spiral channel 4 and the second spiral channel 5 is arranged in the exhaust gas guide section 1. The control device 8 has a closing device 9 comprising a closing element 10 and an element lever 11, wherein the element lever 11 is designed to pivot the closing element 10 by a pivot angle.

[0031] In order to separate and connect the two spiral channels 4, 5, the closing element 10 is arranged in a flow opening 12, which is designed so that the two spiral channels 4, 5 can flow through one another.

[0032] In a first position, the closed position of the closing element 10, as shown in Fig. 1, the two spiral channels 4, 5 can be flowed through completely separately from one another, with the flow opening 12 being completely closed by the closing element 10. The exhaust gas of the internal combustion engine 7 flows through the two spiral channels 4, 5, with a first part of the exhaust gas flowing through the first spiral channel 4 and a second part of the exhaust gas flowing through the second spiral channel 5.

[0033] In a second position of the closing element 10, which is not shown in detail, the flow opening 12 is fully open, and exhaust gas can flow from the first spiral channel 4 into the second spiral channel 5 and vice versa. This means that exhaust gas can flow from one spiral channel 4; 5 into the other spiral channel 5; 4 via the flow opening 12, which has a first flow cross-section 13.

[0034] The closing element 10 is to be positioned in further intermediate positions between the first position and the second position, so that the first flow cross-section 13 can be adapted to a corresponding need in order to achieve the best possible efficiency of the exhaust gas turbocharger 2 in accordance with the exhaust gas quantity flowing through.

[0035] In order to bring about a preferential opening of the first flow cross-section 13, the closing element 10 is designed to have a pot-shaped outer contour 14.

[0036] The closing element 10 has a first element section 15 for closing the first flow cross-section 13 and a second element section 16, which can be used to close a second flow cross-section 17 formed in the exhaust gas guide section 1.

[0037] The second flow cross-section 17 is provided for the flow around the turbine wheel. In other words, this means that the exhaust gas flowing through the second flow cross-section 17 is guided past the turbine wheel, and the turbine wheel is not impacted by the exhaust gas flowing through the second flow cross-section 17. The second flow cross-section 17 is formed in a bypass channel 18, which is also commonly referred to as a so-called wastegate channel. The closing device 9 is designed to be pivotable about a rotational axis 19.

[0038] The closing element 10 of the control device 8 according to the invention, shown in Figures 2 to 7 according to a first and a second exemplary embodiment, also has an approximately pot-shaped outer contour 14, wherein an arm portion 21 of the element lever 11, which is designed to face the closing element 10, is arranged to engage in a cavity 20 of the closing element 10. The closing device 9 designed according to the first exemplary embodiment also has the arm portion 21 in a pot-shaped or cup-shaped manner. The arm portion 21 can be inserted into the closing element 10 to form a movement gap 22, wherein the movement gap 22 is formed between an inner surface 23 of the cavity 20 and an outer surface 24 of the arm portion 21.

[0039] The inner surface 23 and the outer surface 24 contact one another in sections depending on the position of the locking device 9. In other words, this means that in one position of the locking device 9, a part of the outer surface 24 contacts a part of the inner surface 23, thus the movement gap 22 between these parts is designed to be zero, and between the remaining parts of the inner surface 23 and the outer surface 24 is designed to be correspondingly large. Which parts of the inner surface 23 contact which parts of the outer surface 24 and what size they and the movement gap 22 are designed to be varies from position to position of the locking device 9. The movement gap 22 lying between the inner surface 23 and the outer surface 24 is thus designed depending on the position of the control device 8.

[0040] This further means that the inner surface 23 is approximately, but not completely, complementary to the outer surface 24. In other words, the inner surface 23 and the outer surface 24 are identical in shape, although they have different dimensions.

[0041] The closing element 10 has its second element section 16, which has a closing surface 25 for closing the second flow cross-section 17, which is designed to face away from a cover surface 26 of the second element section 16.

[0042] The arm portion 21, which is cup-shaped, is configured to extend from a cavity base 28 of the closing element 10 along a longitudinal axis 27 of the closing element 10 at least as far as the closing surface 25. Advantageously, it is configured to extend over the closing surface 25.

[0043] For axially securing the arm section 21 in the cavity 20, a cover element 29, which in this embodiment is annular, is formed, which, being fastened to the inner surface 23 on the closing element 10, is supported thereon, and at least partially encompasses, or in other words covers, a section surface 30 of the arm section 21 in the radial direction.

[0044] In this first exemplary embodiment, a lateral surface 31 of the outer surface 24 has two differently designed lateral sections: a first lateral section 32 and a second lateral section 33. The two lateral sections 32, 33 are designed like the lateral surfaces of truncated cones, the cover surfaces of which, thus the surfaces of smaller diameter, are arranged facing the cavity floor 28. This results in an expansion of the lateral surface 31 starting from the cavity floor 28. A floor surface 34 of the outer surface 24, which is arranged opposite the cavity floor 28, is flat according to the first exemplary embodiment. Thus, an inner lateral surface 44 of the inner surface 23 and the lateral surface 31 of the outer surface 24 are designed to be identical in shape but have different dimensions, with the lateral surface 31 having at least two different sections: the first lateral section 32 and the second lateral section 33.

[0045] Fig. 5 shows a plan view of the locking device 9 according to the first exemplary embodiment. When the element lever 11 is rotated in the direction of the arrow, the movement gap 22 between the cavity floor 28 and the floor surface 34 is enlarged until the section surface 30 abuts the cover element 29, whereby the arm section 21 is supported axially and radially on the cover element 29. Due to an asymmetrical force application to the arm section 21, the arm section 21 executes a tilting movement in the cavity 20 in the direction of the movement arrow shown in Fig. 3. The tilting movement, which can also be referred to as a coordinated tilting movement, is limited due to the corresponding design of at least the inner surface 23 and the outer surface 24 and preferably the floor surface 34 and / or the cavity floor 28.In other words, this means that a relative movement can be realized between the arm section 21 and the closing element 10, which is low in wear and noise.

[0046] The maximum tilt of the closing element 10 relative to the arm section 21 should preferably not exceed 1.35°. To ensure that this maximum tilt can be maintained, in addition to the axial securing of the arm section 21 by means of the cover element 29, a first angle a is formed between the casing sections 32, 33, which, relative to a virtual plane E, which forms a line parallel to the base surface 34, preferably has a value in a range between 91° and 120°, and preferably 95°.

[0047] Starting from the virtual plane E, the arm portion 21 extends along the longitudinal axis 27 at least over a first length L1, which corresponds to an axial distance between the closing surface 25 and the virtual plane E. Starting from the bottom surface 34, the arm portion 21 extends along the longitudinal axis 27 to the closing surface 25 over a second length L2, so that an axial extension of the first casing portion 32 corresponds to a difference between the second length L2 and the first length L1.

[0048] The cover element 29, starting from the closing surface 25, is arranged with its lower surface 41, which is formed opposite the section surface 30, at an axial distance with a third length L3, wherein a further movement gap 42 is formed between the cover element 29 and the arm section 21, in particular its section surface 30, in particular if the bottom surface 34 contacts the cavity floor 28, but wherein a fourth length L4, over which the arm section 21 extends starting from the virtual plane E along the longitudinal axis 27, which is greater than the first length L1 and less than a sum of the first length L1 and the third length L3. Preferably, the second length L2 is greater than the first length L1, which in a preferred embodiment is 80% of the second length L2.

[0049] The first shell section 32 is inclined relative to the bottom surface 34 at a second angle ß, which generally has a value that is greater than the value of the first angle α, and preferably lies in a value range between 120° and 150°, more preferably has a value of 135°.

[0050] A first transition section 35 is formed between the first shell section 32 and the second shell section 33, connecting the two shell sections 32, 33 to one another in such a way that a continuous course of the shell surface 31 along the longitudinal axis 27 is realized. The first transition section 35 is curved.

[0051] Likewise, between a first inner surface section 36 of the inner surface 44 formed opposite the first shell section 32 and a second inner surface section 37 of the inner surface 44 formed opposite the second shell section 33, a second transition section 38 is formed, which is adapted to the first transition section 35 according to the shape identity and the different dimensions of the inner surface 23 and the outer surface 24.

[0052] In order to realize further free mobility of the closing element 10, the cavity floor 28 has, at least on its floor edge 39, which is formed adjacent to the first casing section 32, a groove 40, which in the present embodiment is designed in the form of an annular groove.

[0053] Figures 6 to 8 depict the control device 8 according to the invention in the second exemplary embodiment. The arm section 21 is secured by means of a pin 43, which extends from the cavity floor 28 of the closing element 10 along the longitudinal axis 27. In Fig. 7, a detailed view VII shows the closing device 9 of the control device 8 according to the invention in the region of the transition sections 35, 38. Naturally, the virtual plane E is arranged in the axial direction along the longitudinal axis 27, intersecting the first transition section 35.

[0054] It should be noted that the lateral surface 31 is understood to mean at least the lateral surface of the arm section 21, which extends in the axial direction along the longitudinal axis 27 from the base surface 34 over the second length L2. This also applies to the inner lateral surface 44. In other words, this means that the lateral surfaces 31, 44 can contact each other at any point, at least in the axial direction, over the second length L2.

[0055] In a third embodiment of the control device 8 according to the invention, the closing surface 25 is inclined relative to the longitudinal axis 27, as illustrated in Fig. 9. To realize a lightweight construction, the second element section 16 could also be hollow or at least partially hollow.

[0056] The control device 8 according to the invention now comprises a rotationally symmetrical surface formed between the closing element 10 and the arm section 21, which realizes an axial force introduction, a concentric positioning, and a radial stop of the closing element 10. The tendency of the closing element 10 and the arm section 21 to wear, which occurs as a result of pressure pulsations during operation of the exhaust gas turbocharger 2, can be eliminated by a conical guide, put simply. An axial contact surface formed between the cavity floor 28 and the floor surface 34 is further provided to bring about a damage-free force introduction. An outer radial portion of a total contact surface between the closing element 10 and the arm section 21 is crucial for bringing about reduced mobility initiated by pressure pulsations during operation.Thus, the force pulsation is minimized overall in the overall kinematics of the control device 8 according to the invention. List of reference symbols.

[0057] 1 exhaust gas section

[0058] 2 exhaust gas turbochargers

[0059] 3 Inlet channel

[0060] 4 First spiral channel

[0061] 5 Second spiral channel

[0062] 6 exhaust manifold

[0063] 7 Internal combustion engine

[0064] 8 Control device

[0065] 9 Locking device

[0066] 10 locking element

[0067] 11 Element lever

[0068] 12 Flow opening

[0069] 13 First flow cross-section

[0070] 14 Outer contour

[0071] 15 First element section

[0072] 16 Second element section

[0073] 17 Second flow cross-section

[0074] 18 Bypass canal

[0075] 19 axis of rotation

[0076] 20 cavity

[0077] 21 arm section

[0078] 22 Movement gap

[0079] 23 inner surface

[0080] 24 exterior area

[0081] 25 locking surface

[0082] 26 deck area

[0083] 27 Longitudinal axis

[0084] 28 hollow floor

[0085] 29 Cover element

[0086] 30 section area

[0087] 31 Shell surface 2 First shell section 3 Second shell section 4 Bottom surface 5 First transition section 6 First inner surface section 7 Second inner surface section 8 Second transition section 9 Bottom edge 0 Groove 1 Bottom surface 2 Further movement gap 3 Pin 4 Inner shell surface

[0088] E Virtual Level

[0089] L1 First Length

[0090] L2 Second Length

[0091] L3 Third Length

[0092] L4 Fourth length a First angle ß Second angle

Claims

Claims: Control device (8) of an exhaust gas routing section (1) of an exhaust gas turbocharger (2), wherein the control device (8) has a closing device (9) comprising a closing element (10) and an element lever (11), wherein the closing device (9) is pivotable about a pivot axis (19), and wherein the closing element (10) is configured for opening and closing a first flow cross-section (13) of the exhaust gas routing section (1), wherein the first flow cross-section (13) is formed in a partition located between a first spiral channel (4) of the exhaust gas routing section (1) and a second spiral channel (5) of the exhaust gas routing section (1), and wherein the exhaust gas routing section (1) has a second flow cross-section (17) which is associated with a bypass channel (18) formed in the exhaust gas routing section (1), which is configured to bypass an inflow to a turbine wheel formed in the exhaust gas routing section (1).and wherein the closing element (10) has a first element section (15) for closing the first flow cross-section (13) and a second element section (16) which can be used to close the second flow cross-section (17), and wherein the element lever (11) has an arm section (21) designed to engage in a cavity (20) of the closing element (10), and wherein the cavity (20) has an inner surface (23) and the arm section (21) has an outer surface (24) opposite the inner surface (23), characterized in that an inner surface (44) of the inner surface (23) and a surface (31) of the outer surface (24) are identical in form but have different dimensions, wherein the surface (31) has at least two different sections (32, 33). Control device (8) according to claim 1, characterized in that a movement gap (22) is formed between the inner surface (23) and the outer surface (24), the position of which depends on the position of the control device (8). Control device (8) according to claim 1 or 2, characterized in that the arm section (21) is designed to be axially and / or radially supported on a cover element (29) of the closing device (9). Control device (8) according to any one of the preceding claims, characterized in that the inner surface (44) and the outer surface (31) have at least one frustoconical section.Control device (8) according to one of the preceding claims, characterized in that the arm section (21) extends along the longitudinal axis (27) from its base surface (34), which is formed opposite a cavity base (28) of the closing element (10), at least to a closing surface (25) of the second element section (16). Control device (8) according to one of the preceding claims, characterized in that a first transition section (35) is formed between the first shell section (32) and the second shell section (33), which connects the two shell sections (32, 33) to each other in order to bring about a continuous course of the shell surface (31) along the longitudinal axis (27). Control device (8) according to claim 6, characterized in that the first transition section (35) is curved. Control device (8) according to any one of the preceding claims, characterized in that the cavity floor (28) has a groove (40) at least at its bottom edge (39), which is adjacent to the first shell section (32). Control device (8) according to any one of the preceding claims, characterized in that the arm section (21) is cup-shaped. Control device (8) according to any one of the preceding claims, characterized in that the arm section (21) is secured by means of a pin (43) extending from the cavity floor (28) along the longitudinal axis (27).

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