Control device for exhaust gas guide part in exhaust gas turbocharger

Abstract

An improved control system for an exhaust gas guide section of an exhaust gas turbocharger is provided. The present invention relates to a control device (8) for an exhaust gas guide part (1) in an exhaust gas turbocharger (2), the control device (8) having a closing device (9) including a closing element (10) and an element lever (11) and rotatable about a rotation axis (19), the closing element (10) being formed to open and close a first flow cross section (13) of the exhaust gas guide part (1), the first flow cross section (13) being formed in a partition wall located between a first spiral channel (4) of the exhaust gas guide part (1) and a second spiral channel (5) of the exhaust gas guide part (1), the exhaust gas guide part (1) being provided with a bypass channel (14) formed in ... The exhaust gas guide part (1) has a second flow cross section (17) assigned to the first channel (18), a bypass channel is designed to divert the flow towards the turbine wheel formed in the exhaust gas guide part (1), the closure element (10) has a first element part (15) for closing the first flow cross section (13) and a second element part (16) which can be used for closing the second flow cross section (17), the element lever (11) has an arm part (21) formed to engage in a hollow space (20) of the closure element (10), the hollow space (20) has an inner surface (23) and the arm part (21) has an outer surface (24) formed opposite the inner surface (23). According to the present invention, the inner peripheral surface (44) of the inner surface (23) and the peripheral surface (31) of the outer surface (24) are designed to have different dimensions but the same shape, and the peripheral surface (31) has at least two different peripheral portions (32, 33).

Description

[Technical field]

[0001] The present invention relates to a control device for an exhaust gas guide in an exhaust gas turbocharger of the type specified in the preamble of claim 1 . [Background technology]

[0002] Known exhaust gas guides in exhaust gas turbochargers are exhaust gas guides with a control device for controlling a fluid, generally exhaust gas, flowing through the exhaust gas guide. The control device is provided for opening and closing a bypass passage in the through-flow exhaust gas guide in order to bypass a turbine wheel of the exhaust gas guide, which is arranged rotatably in a wheel chamber of the exhaust gas guide. Furthermore, a flow opening formed between two helical passages of the exhaust gas guide can be opened and closed by the control device, so that exhaust gas can flow from one helical passage to the other helical passage and vice versa.

[0003] Such a control device makes it possible to completely or partially bypass the turbine wheel at certain operating points of the exhaust gas turbocharger, in particular at operating points with high flow rates, thereby enabling an efficient operation of the exhaust gas turbocharger, which depends on the specific opening characteristics of the control device, which has to be set to suit the requirements of the drive unit, in particular the internal combustion engine, connected to the exhaust gas turbocharger.

[0004] The control device has several parts connected to each other, and a relative movement of the individual parts to each other is also possible. The closing element of the control device, which is provided for closing the bypass passage and / or the flow opening, is therefore mobile with respect to a lever arm of the control device which is designed to move said closing element and which receives it at one end. This mobility is necessary, for example, in order to be able to avoid the lever arm getting caught in the exhaust gas guide when it pivots together with the closing element. The relative mobility of the two parts to each other causes wear of the control device during operation of the exhaust gas turbocharger, which must at least be reduced.

[0005] From DE 101 02 04 13 A1 it is possible to read of a control device for an exhaust gas turbocharger, which has a closing element accommodated in a lever arm of the control device. The lever arm is designed to project into the hollow space of the closing element. In order to reduce wear, one end of the lever arm projecting into the hollow space is designed to partially bring into contact with the closing element. For this purpose, a guide element is provided which has a guide surface, on which the end of the lever arm can come into contact with the closing element.

[0006] A control device for an exhaust gas turbocharger can also be read in the following patent document 2, which has a closing element and a lever arm protruding into the closing element, the end of which has a conically and cylindrically shaped guide element designed to provide a sliding contact. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] German Patent Application Publication No. 10 2017 202 132 A1 [Patent Document 2] DE 10 2015 011 256 A1 Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE DISCLOSURE It is an object of the present invention to provide an improved control of an exhaust gas guide in an exhaust gas turbocharger. [Means for solving the problem]

[0009] The object is achieved according to the invention by a device for controlling an exhaust gas guide in an exhaust gas turbocharger having the features of claim 1. Advantageous embodiments, including expedient and non-obvious developments of the invention, are set out in the dependent claims.

[0010] The control device of an exhaust gas guide part in an exhaust gas turbocharger according to the invention has a closing device including a closing element and an element lever, the closing device being pivotable about a rotation axis. The closing element is designed to open and close a first flow cross section of the exhaust gas guide part, the first flow cross section being formed in a partition located between a first spiral passage of the exhaust gas guide part and a second spiral passage of the exhaust gas guide part. The exhaust gas guide part has a second flow cross section assigned to a bypass passage formed in the exhaust gas guide part, the bypass passage being designed to divert the flow towards a turbine wheel formed in the exhaust gas guide part. The closing element has a first element part for closing the first flow cross section and a second element part which is available for closing the second flow cross section. The element lever is designed with an arm part which is formed to engage in a hollow space of the closing element. The hollow space has an inner surface and the arm part has an outer surface formed opposite the inner surface. According to the present invention, the inner peripheral surface of the inner surface and the peripheral surface (outer peripheral surface) of the outer surface are designed to have different dimensions and the same shape, and the peripheral surface (outer peripheral surface) has at least two different peripheries.

[0011] In principle, it is advantageous to realize a relative movement between the closing element and the element lever, so that tilting or jamming of the closing element in the exhaust gas guide can be prevented. With the control device according to the invention, the contact between the element lever, in particular the arm part and the closing element, can occur at various points of the arm part and the closing element, so that the wear of the element lever and / or the closing element due to the relative movement is significantly reduced. In other words, this means that on the one hand the contact between the arm part 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 formed with the required size. Furthermore, the optimal formation of the size of the contact leads to an optimal formation of the size of the contact surface due to this contact, which also reduces the noise generation.

[0012] In one embodiment of the control device according to the invention, a dynamic gap is formed between the inner surface and the outer surface, which dynamic gap is formed as a function of the position of the control device, which means that the inner surface and the outer surface can be formed as a function of the operating point of the drive unit connected to the exhaust gas turbocharger.

[0013] In another embodiment, the arm portion is configured to be supported axially and / or radially on the cover element of the closure device so that the arm portion is fixedly accommodated in the hollow space of the closure element.

[0014] The inner and outer circumferential surfaces preferably have at least one frusto-conical portion.

[0015] In another advantageous embodiment, in order to achieve a favorable sealing performance, the arm portion is formed so as to extend along the longitudinal axis from a bottom surface of the arm portion formed opposite the bottom of the hollow space of the closure element to at least the closure surface of the second element portion.

[0016] Particularly preferably, the first transition between the first and second periphery is designed to connect the two periphery to one another in order to provide a constant contour of the periphery along the longitudinal axis, so that an unhindered sliding movement of the arms on the closure element can be achieved, whereby it is furthermore advantageous if the first transition is designed to be curved.

[0017] Further improved sliding and therefore further reduced wear can be achieved if the hollow space bottom has a groove at least on its bottom edge formed adjacent to the first periphery.

[0018] Alternatively, the arm portion can be secured by a pin extending from the bottom of the hollow space along the longitudinal axis.

[0019] Overall, it can be said that the control device according to the invention is designed in such a way that it has reduced wear even at high temperatures and that the heat transfer from the closing element to the lever element is reduced, which leads to a lower component temperature. The simple design of the contours of the closing element and the lever element, in particular of their mutual contact surfaces, also allows for a simple and inexpensive production, in particular by casting methods.

[0020] The weight of the control device is reduced by forming the closure element and the arm in a pot shape.

[0021] Further advantages, features and details of the invention emerge from the following description of preferred exemplary embodiments and on the basis of the drawings. The features and combinations of features mentioned above in the description and those mentioned below in the description of the figures and / or shown only in the figures can be used not only in the respective described combinations but also in other combinations or alone without departing from the scope of the invention. Identical or functionally identical elements are assigned the same reference signs. [Brief description of the drawings]

[0022] [Figure 1]FIG. 1 is a perspective view in cross section along a cut surface of an exhaust gas guide part of an exhaust gas turbocharger with a control device according to the prior art; [Diagram 2] 1 is a perspective view of a closing device of a control device according to the invention for an exhaust gas turbocharger according to a first exemplary embodiment; [Diagram 3] FIG. 3 is a cross-sectional view of the closure device of FIG. 2. [Figure 4] 3 is another cross-sectional view of the closure device of FIG. 2. [Diagram 5] FIG. 3 is a plan view of the closure device of FIG. 2. [Figure 6] 4 is a cross-sectional view of a closure device of a control device according to the present invention according to a second exemplary embodiment. [Figure 7] FIG. 7 is a detailed view of the closure device of FIG. 6. [Figure 8] FIG. 2 is an exploded perspective view of a control device according to the present invention according to a second exemplary embodiment. [Figure 9] FIG. 13 is a cross-sectional view of a control device according to the present invention according to a third exemplary embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The inventive through-flow exhaust gas guide part 1 of an exhaust gas turbocharger 2 configured as shown in Figure 1 comprises an inlet passage 3 through which a fluid flow, generally the exhaust gas of an internal combustion engine 7, can enter the exhaust gas guide part 1, a first spiral passage 4 and a second spiral passage 5 downstream of the inlet passage 3 for regulating the flow, and an outlet passage (not shown in more detail) downstream of the spiral passages 4, 5, through which the exhaust gases from the exhaust gas guide part 1 can be precisely released. A wheel chamber (not shown in more detail) is formed between the spiral passages 4, 5 and the outlet passage, in which a turbine wheel (not shown in more detail) is rotatably accommodated.

[0024] In this exemplary embodiment, the exhaust gas guide part 1 is connected to an exhaust manifold 6 of an internal combustion engine 7, so that the exhaust gases of the internal combustion engine 7 can enter the spiral passages 4, 5 via the inlet passage 3 and act on the turbine wheel.

[0025] In order 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 is arranged in the exhaust gas guiding part 1 for separating and connecting the first helical passage 4 and the second helical passage 5. The control device 8 has a closing device 9 which comprises a closing element 10 and an element lever 11 which is designed to pivot the closing element 10 through a pivot angle.

[0026] To separate and connect the two helical passages 4, 5, a closure element 10 is arranged in a flow opening 12 which is formed to allow the two helical passages 4, 5 to flow through one another.

[0027] 1, in the first position, i.e. the closed position of the closure element 10, the two helical passages 4, 5 can be flowed through completely separately and the flow opening 12 is completely closed by means of the closure element 10. The exhaust gases of the internal combustion engine 7 flow through the two helical passages 4, 5, with a first portion of the exhaust gases flowing through the first helical passage 4 and a second portion of the exhaust gases flowing through the second helical passage 5.

[0028] In the second position of the closure element 10, which is not shown in detail, the flow openings 12 are fully open and the exhaust gases can pass from the first helical passage 4 to the second helical passage 5 and vice versa. This means that the exhaust gases can pass from one helical passage 4, 5 to the other helical passage 5, 4 via the flow openings 12 with the first flow cross-section 13.

[0029] The closing element 10 can be positioned in further intermediate positions between the first and second positions, whereby the first flow cross section 13 can be adapted to the corresponding requirements in order to achieve the highest possible efficiency of the exhaust gas turbocharger 2 depending on the exhaust gas flow rate.

[0030] In order to provide a preferred opening of the first flow cross section 13, the closure element 10 is designed with a pot-shaped outer contour 14.

[0031] The closing element 10 has a first element part 15 for closing the first flow cross section 13 and a second element part 16 which can be used to close a second flow cross section 17 formed in the exhaust gas guide part 1.

[0032] The second flow cross section 17 is provided for the flow around the turbine wheel. In other words, this means that the exhaust gases flowing through the second flow cross section 17 are guided past the turbine wheel, so that they do not act on the turbine wheel. The second flow cross section 17 is usually formed in a bypass passage 18, also known as a wastegate passage. The closing device 9 is designed to be pivotable about a rotation axis 19.

[0033] The closure element 10 of the control device 8 according to the present invention shown in Figures 2 to 7 according to the first and second exemplary embodiments also has an approximately pot-shaped outer contour 14, in which the arm part 21 of the element lever 11 formed towards the closure element 10 is engaged and arranged in the hollow space 20 of the closure element 10.

[0034] The closure device 9 formed according to the first exemplary embodiment also has a pot-shaped or pot-shaped designed arm 21 which can be inserted into the closure element 10 forming a movement gap 22, which is formed between an inner surface 23 of the hollow space 20 and an outer surface 24 of the arm 21.

[0035] The inner surface 23 and the outer surface 24 are partially in contact with each other depending on the position of the closing device 9. In other words, this means that in the position of the closing device 9, a part of the outer surface 24 is in contact with a part of the inner surface 23, so that the movement gap 22 between these parts is formed to be approximately zero, and between the remaining parts of the inner surface 23 and the outer surface 24, it is formed to be of a corresponding size. In that case, which part of the inner surface 23 is in contact with which part of the outer surface 24 and how large the movement gap 22 is formed therebetween depend on the position of the closing device 9. Thus, the movement gap 22 located between the inner surface 23 and the outer surface 24 is formed depending on the position of the control device 8.

[0036] This further means that the inner surface 23 is approximately, but not perfectly, complementary to the outer surface 24. In other words, the inner surface 23 and the outer surface 24 are designed to be the same shape but have different dimensions.

[0037] The closure element 10 has a second element part 16 having a closure surface 25 formed on the side opposite to the cover surface 26 of the second element part 16 to bring about closure of the second flow cross section 17.

[0038] The pot-shaped designed arm 21 is formed so as to extend from the hollow space bottom 28 of the closure element 10 along the longitudinal axis 27 of the closure element 10 at least up to the closure surface 25. Advantageously, the arm 21 is designed so as to extend beyond the closure surface 25.

[0039] For axial fixing of the arm portion 21 in the hollow space 20, in this exemplary embodiment an annular cover element 29 is formed which is attached to the inner surface 23 of the closure element 10, is supported on this inner surface 23 and at least partially surrounds, or in other words covers, the partial surface 30 of the arm portion 21 in the radial direction.

[0040] In this first exemplary embodiment, the circumferential surface (outer peripheral surface) 31 of the outer surface 24 has two differently formed circumferential parts, namely a first circumferential part 32 and a second circumferential part 33. The two circumferential parts 32, 33 are formed according to the circumferential surface of a truncated cone, the cover surface of the two circumferential parts, and therefore the surface with the smaller diameter, being arranged towards the hollow space bottom 28. This results in an expansion of the circumferential surface 31 from the hollow space bottom 28. The bottom surface 34 of the outer surface 24, which is arranged opposite the hollow space bottom 28, is formed flat according to the first exemplary embodiment. The inner circumferential surface 44 of the inner surface 23 and the circumferential surface 31 of the outer surface 24 are thus designed to be identical with different dimensions, the circumferential surface 31 having at least two different parts, the first circumferential part 32 and the second circumferential part 33.

[0041] In Fig. 5 the closing device 9 according to the first exemplary embodiment is shown in a plan view. When the lever element 11 is rotated in the direction of the arrow, the movement gap 22 between the hollow space bottom 28 and the bottom surface 34 is enlarged until a maximum abutment of the part surface 30 on the cover element 29, which supports the arm part 21 axially and radially on the cover element 29, is achieved, whereby due to the asymmetrical force action on the arm part 21, the arm part 21 performs a tilting movement in the hollow space 20 in the direction of the movement arrow shown in Fig. 3.

[0042] This tilting can also be called regulated tilting, since a limit is provided to the tilting by a corresponding design of at least the inner surface 23 and the outer surface 24, and preferably the bottom surface 34 and / or the hollow space bottom 28. In other words, this means that a low-wear and low-noise relative movement between the arm part 21 and the closure element 10 can be achieved.

[0043] The maximum inclination of the closure element 10 relative to the arm 21 should preferably not exceed 1.35°. In order to be able to comply with this maximum inclination, in addition to the axial fixing of the arm 21 by the cover element 29, a first angle α is formed between the circumferential parts 32, 33 with respect to an imaginary plane E parallel to the bottom surface 34, the first angle α preferably having a value in the range of 91° to 120°, more preferably 95°.

[0044] The arm portion 21 extends along the longitudinal axis 27 from the imaginary plane E over at least a first length L1 corresponding to the axial distance between the closure surface 25 and the imaginary plane E. The arm portion 21 extends from the bottom surface 34 along the longitudinal axis 27 to the closure surface 25 over a second length L2, whereby the axial extension of the first circumferential portion 32 corresponds to the difference between the second length L2 and the first length L1.

[0045] The cover element 29 is arranged with its underside 41, formed opposite the partial surface 30, at an axial distance of a third length L3 from the closing surface 25, in which case another movement gap 42 is formed between the cover element 29 and the arm part 21, in particular its partial surface 30, in particular when the bottom surface 34 comes into contact with the hollow space bottom 28, but the fourth length L4, along which the arm part 21 extends from the imaginary plane E along the longitudinal axis 27, is greater than the first length L1 and less than the sum of the first length L1 and the third length L3.

[0046] Preferably, the second length L2 is greater than the first length L1, and in a preferred exemplary embodiment is 80% of the second length L2.

[0047] The first peripheral portion 32 is inclined at a second angle β with respect to the bottom surface 34, the second angle basically having a value greater than the value of the first angle α, preferably in the range of 120° to 150°, and more preferably having a value of 135°.

[0048] Between the first peripheral portion 32 and the second peripheral portion 33, a first transition portion 35 is formed, which connects the two peripheral portions 32, 33 to one another, in such a way that a constant contour shape of the peripheral surface 31 is realized along the longitudinal axis 27. In that case, the first transition portion 35 is formed in a curve.

[0049] Similarly, a second transition portion 38 is formed between a first inner surface portion 36 of the inner circumferential surface 44 formed opposite the first circumferential portion 32 and a second inner surface portion 37 of the inner circumferential surface 44 formed opposite the second circumferential portion 33, which is designed to match the first transition portion 35 due to the same shape and different dimensions of the inner surface 23 and the outer surface 24.

[0050] In order to achieve even greater freedom of movement of the closure element 10, the hollow space bottom 28 has at least its bottom edge 39 formed adjacent to the first periphery 32 a groove 40 which in this exemplary embodiment is formed in the form of an annular groove.

[0051] In figures 6 to 8 a control device 8 according to the invention is shown according to a second exemplary embodiment. The arm 21 is fixed by means of a pin 43 formed to extend along the longitudinal axis 27 from the hollow space bottom 28 of the closure element 10. In figure 7 the closure device 9 of the control device 8 according to the invention is shown in a detailed view VII in the region of the transitions 35, 38. Naturally, an imaginary plane E is arranged axially along the longitudinal axis 27 intersecting the first transition 35.

[0052] It should be noted that the peripheral surface 31 should be understood as at least the peripheral surface of the arm portion 21 that is formed to extend from the bottom surface 34 axially along the longitudinal axis 27 over the second length L2. The same applies to the inner peripheral surface 44. In other words, this means that the peripheral surfaces 31, 44 can come into contact with each other at any point over at least the second length L2 in the axial direction.

[0053] In a third exemplary embodiment of the control device 8 according to the invention, the closing surface 25 is formed inclined relative to the longitudinal axis 27, as shown in Fig. 9. In order to achieve a lightweight construction, the second element part 16 can also be formed hollow or at least partially hollow.

[0054] The control device 8 according to the invention comprises a rotationally symmetrical surface formed between the closing element 10 and the arm part 21, which realizes the axial force introduction, the concentric positioning and the radial stop of the closing element 10. The tendency to wear of the closing element 10 and the arm part 21 as a result of pressure pulsations during operation of the exhaust gas turbocharger 2 can be eliminated in simple terms by means of a conical guide. In order to provide a damage-free force introduction, an axial contact surface is further provided which is formed between the hollow space bottom 28 and the bottom surface 34. The radial part located outside the total contact surface between the closing element 10 and the arm part 21 is important in order to provide a reduction in the mobility initiated by the pressure pulsations during operation. Overall, therefore, force pulsations are minimized in the overall kinematics of the control device 8 according to the invention. [Explanation of symbols]

[0055] 1 Exhaust gas guide section 2 Exhaust gas turbocharger 3 Entrance passage 4. First Spiral Passage 5 Second Spiral Passage 6 Exhaust manifold 7. Internal Combustion Engine 8 Control device 9 Closing device 10 Closure elements 11 Element Lever 12 Flow opening 13 First flow section 14 Outer contour 15 First element 16 Second element 17 Second flow section 18 Bypass Passage 19 Rotational Axis 20 Hollow space 21 Arm section 22 Movement gap 23 Inside 24 Exterior 25 Closed surface 26 Cover surface 27 Longitudinal axis 28 Hollow space bottom 29 Cover Elements 30 partial surfaces 31 Peripheral surface 32 First Circumference 33 Second Circumference 34 Bottom 35 First Transition 36 First inner surface 37 Second inner surface 38 Second Transition 39 Bottom edge 40 grooves 41 Bottom surface 42 Another Movement Gap 43 pin 44 Inner surface E Virtual plane L1 First length L2 Second length L3 Third length L4 Fourth length α First angle β Second angle

Claims

1. A control device (8) for an exhaust gas guide part (1) in an exhaust gas turbocharger (2), the control device (8) having a closing device (9) which includes a closing element (10) and an element lever (11) and is pivotable about a rotation axis (19), the closing element (10) being configured to open and close a first flow cross section (13) of the exhaust gas guide part (1), the first flow cross section (13) being configured in a partition located between a first spiral channel (4) of the exhaust gas guide part (1) and a second spiral channel (5) of the exhaust gas guide part (1), the exhaust gas guide part (1) being assigned to a bypass channel (18) formed in the exhaust gas guide part (1), a bypass channel designed to divert a flow towards a turbine wheel formed in the exhaust gas guide part (1), the closing element (10) having a first element part (15) for closing the first flow cross section (13) and a second element part (16) which can be used to close the second flow cross section (17), the element lever (11) having an arm part (21) formed to engage in a hollow space (20) of the closing element (10), the hollow space (20) having an inner surface (23) and the arm part (21) having an outer surface (24) formed opposite the inner surface (23), The inner peripheral surface (44) of the inner surface (23) and the peripheral surface (31) of the outer surface (24) are designed to have different dimensions and the same shape, and the peripheral surface (31) has at least two different peripheral portions (32, 33). A control device comprising:

2. A motion gap (22) is formed between the inner surface (23) and the outer surface (24) according to the position of the control device (8).

2. The control device (8) according to claim 1 .

3. The arm (21) is configured to be supported axially and / or radially on a cover element (29) of the closure device (9).

3. The control device (8) according to claim 1 or 2.

4. The inner circumferential surface (44) and the peripheral surface (31) have at least one frustoconical portion. The control device (8) according to any one of claims 1 to 3.

5. The arm portion (21) is formed so as to extend from a bottom surface (34) of the arm portion formed opposite to the bottom (28) of the hollow space of the closure element (10) along a longitudinal axis (27) to at least the closure surface (25) of the second element portion (16). A control device (8) according to any one of claims 1 to 4.

6. A first transition portion (35) is formed between the first peripheral portion (32) and the second peripheral portion (33), the first transition portion (35) being configured to connect the two peripheral portions (32, 33) to one another in order to provide a constant profile of the peripheral surface (31) along the longitudinal axis (27). A control device (8) according to any one of claims 1 to 5.

7. The first transition portion (35) is formed in a curved shape.

7. The control device (8) according to claim 6.

8. The hollow space bottom (28) has a groove (40) at least on a bottom edge (39) of the hollow space bottom formed adjacent to the first perimeter (32). A control device (8) according to any one of claims 1 to 7.

9. The arm portion (21) is formed in a pot shape. A control device (8) according to any one of the preceding claims.

10. The arm portion (21) is fixed using a pin (43) formed to extend from the bottom (28) of the hollow space along the longitudinal axis (27). A control device (8) according to any one of the preceding claims.

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