Turbines and turbochargers

Abstract

A turbine according to at least one embodiment includes a turbine wheel having a plurality of blades, a turbine casing that forms a turbine wheel housing space that houses the turbine wheel inside, and a waste gas bypass valve that controls a flow rate of waste gas that flows through a waste gas bypass valve flow path formed inside the turbine casing. The waste gas bypass valve flow path is configured to connect a scroll flow path formed inside the turbine casing and a region in the turbine wheel housing space that is upstream of trailing edges of the plurality of blades.

Description

Technical Field

[0001] This disclosure relates to turbines and turbochargers. Background Technology

[0002] In turbochargers, there are cases where an exhaust gas bypass valve is installed to suppress excessive boost. The exhaust gas bypass valve regulates the amount of exhaust gas flowing into the turbine by opening and closing the bypass passage that bypasses the turbine of the turbocharger (see, for example, Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-127989 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In the exhaust gas bypass valve flow path described in Patent Document 1, the exhaust gas is configured to flow downstream of the turbine to bypass the turbine impeller blades. Therefore, when the exhaust gas in the exhaust gas bypass valve flow path is allowed to flow in order to divert exhaust gas exceeding the turbine throughput, the exhaust gas flowing through the exhaust gas bypass valve flow path cannot contribute to increasing the turbine output.

[0008] In view of the above, the object of at least one embodiment of the present disclosure is to improve the turbine output when exhaust gas is diverted to the exhaust gas bypass valve flow path.

[0009] Technical solutions for solving the problem

[0010] (1) At least one embodiment of the present disclosure provides a turbine comprising:

[0011] A turbine impeller, which has multiple blades;

[0012] The turbine housing forms a turbine impeller housing space within it to accommodate the turbine impeller;

[0013] An exhaust gas bypass valve is used to control the exhaust gas flow rate through an exhaust gas bypass valve path formed inside the turbine housing, wherein...

[0014] The exhaust gas bypass valve flow path is configured to connect the vortex flow path formed inside the turbine housing with the region in the turbine impeller housing that is upstream of the trailing edge of the plurality of blades.

[0015] (2) At least one embodiment of the present disclosure provides a turbocharger having a turbine with the structure of (1).

[0016] Invention Effects

[0017] According to at least one embodiment of this disclosure, the turbine output can be improved when exhaust gas is diverted to the exhaust gas bypass valve path. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view illustrating one example of a turbocharger with several implementations.

[0019] Figure 2 This is a perspective view of the appearance of a turbine impeller in several implementations.

[0020] Figure 3 This is a schematic diagram showing a partial cross-section of a turbine in several embodiments.

[0021] Figure 4 This is a schematic diagram showing a partial cross-section of a turbine according to another embodiment.

[0022] Figure 5A It is a schematic representation. Figure 3 An example of a V-V view section in the diagram.

[0023] Figure 5B It is a schematic representation. Figure 3 Another example of a V-V view section in the diagram.

[0024] Figure 5C It is a schematic representation. Figure 3 Another example of a V-V view section in the diagram.

[0025] Figure 5D It is a schematic representation. Figure 3 Another example of a V-V view section in the diagram.

[0026] Figure 5E It is a schematic representation. Figure 3 Another example of a V-V view section in the diagram.

[0027] Figure 5F It is a schematic representation. Figure 3 Another example of a V-V view section in the diagram.

[0028] Figure 6 This is a schematic cross-sectional view of a turbine according to another embodiment.

[0029] Figure 7 This is a schematic cross-sectional view of a turbine according to another embodiment.

[0030] Figure 8A This is a schematic cross-sectional view of a turbine according to another embodiment.

[0031] Figure 8BThis is a schematic cross-sectional view of a turbine according to another embodiment.

[0032] Figure 8C This is a schematic cross-sectional view of a turbine according to another embodiment.

[0033] Figure 9A This is a schematic cross-sectional view of a turbine according to another embodiment.

[0034] Figure 9B This is a schematic cross-sectional view of a turbine according to another embodiment.

[0035] Figure 9C This is a schematic cross-sectional view of a turbine according to another embodiment. Detailed Implementation

[0036] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative arrangements of the structural parts described in the embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, but are merely illustrative examples.

[0037] For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" indicate relative or absolute configurations. They not only strictly indicate such configurations, but also indicate the state of relative displacement by angle or distance with tolerances or with a degree of ability to achieve the same function.

[0038] For example, expressions such as "same," "equal," and "homogeneous" that indicate that things are in an equal state not only indicate a state of strict equality, but also indicate a state of having a tolerance or a difference in the degree to which they can achieve the same function.

[0039] For example, the descriptions of shapes such as quadrilaterals and cylindrical shapes not only refer to quadrilaterals and cylindrical shapes in the strict sense of geometry, but also to shapes that include concave and convex parts, chamfered parts, etc., within the range that can achieve the same effect.

[0040] On the other hand, the expression "having," "containing," "possessing," "including," or "having" a constituent element is not an exclusive expression that excludes the existence of other constituent elements.

[0041] (Overall structure of turbocharger 1)

[0042] Figure 1 This is a cross-sectional view showing one example of a turbocharger 1 with several implementations.

[0043] The turbocharger 1 in several embodiments is, for example, an exhaust turbocharger used to boost the intake air of an engine mounted in a vehicle such as an automobile.

[0044] The turbocharger 1 includes a turbine impeller 3 and a compressor impeller 4 connected to a rotor shaft 2 as a rotation axis, a housing (turbine casing) 5 that rotatably houses the turbine impeller 3, and a housing (compressor casing) 6 that rotatably houses the compressor impeller 4. Furthermore, the turbine casing 5 includes a vortex section 7 having an internal vortex flow path 7a. The compressor casing 6 includes a vortex section 8 having an internal vortex flow path 8a.

[0045] Several embodiments of the turbine 30 include a turbine impeller 3 and a housing 5. Several embodiments of the compressor 40 include a compressor impeller 4 and a housing 6.

[0046] (Turbine impeller 3)

[0047] Figure 2 This is a perspective view of the appearance of the turbine impeller 3 in several embodiments.

[0048] Figure 3 This is a schematic cross-section of a turbine 30 according to several embodiments.

[0049] Several embodiments of the turbine impeller 3 are impellers connected to the rotor shaft (rotating shaft) 2 and rotating about the rotation axis AXw. Several embodiments of the turbine impeller 3 include: a hub 31 having a hub surface 32 that is inclined relative to the rotation axis AXw in a cross-section along the rotation axis AXw; and a plurality of blades (moving blades) 33 disposed on the hub surface 32. Furthermore, Figure 1 , 2 The turbine impeller 3 shown is a radial flow turbine, but it could also be a mixed flow turbine. Figure 2 In the diagram, arrow R indicates the direction of rotation of turbine impeller 3. Multiple blades 33 are arranged at intervals along the circumference of turbine impeller 3.

[0050] In several embodiments of the turbine impeller 3, a throat 35 (see reference) is formed with the smallest flow path area between two circumferentially adjacent blades 33. Figure 3 It should be noted that in several embodiments of the turbine impeller 3, the throat 35 is formed in the blade body of the blade 33 in the region on the side of the leading edge 36 compared to the trailing edge 37 of the blade.

[0051] It should be noted that the perspective view is omitted, but the compressor impeller 4 in several embodiments also has the same structure as the turbine impeller 3 in several embodiments. That is, the compressor impeller 4 in several embodiments is an impeller connected to the rotor shaft (rotation shaft) 2 and rotating about the rotation axis AXw. The compressor impeller 4 in several embodiments has: a hub 41, which has a hub surface 42 that is inclined relative to the rotation axis AXw in a cross section along the rotation axis AXw; and a plurality of blades (moving blades) 43, which are disposed on the hub surface 42. The blades 43 are arranged at intervals along the circumference of the compressor impeller 4.

[0052] In the following description, the direction of extension of the rotation axis AXw will be referred to as the axial direction, the radial direction centered on the rotation axis AXw will be referred to as the radial direction, and the circumferential direction centered on the rotation axis AXw will be referred to as the circumferential direction.

[0053] In the turbocharger 1 configured in this way, the working fluid of the turbine 30, namely the exhaust gas, flows from the leading edge 36 of the turbine impeller 3 toward the trailing edge 37. As a result, the turbine impeller 3 rotates, and at the same time, the compressor impeller 4 of the compressor 40, which is connected via the rotor shaft 2, rotates. As a result, the intake air flowing in from the inlet 40a of the compressor 40 is compressed by the compressor impeller 4 as it flows from the leading edge 46 to the trailing edge 47.

[0054] (Summary of waste gas bypass valve flow path 110)

[0055] As described above, the turbine 30 in several embodiments includes a turbine impeller 3 and a turbine housing 5 having a turbine impeller housing space 53 internally formed to accommodate the turbine impeller 3. The turbine 30 in several embodiments includes an exhaust gas bypass valve 55 for controlling the flow rate of exhaust gas flowing through an exhaust gas bypass valve flow path 110 formed inside the turbine housing 5. In several embodiments, for example... Figure 3 The following Figure 4 , Figure 6 , Figure 7 and Figures 8A to 8C As shown, the exhaust bypass valve 55 can be constructed as a swing valve, the radially outer position of which is swingably supported on the turbine housing 5. Additionally, as described later... Figures 9A to 9C As shown, the exhaust bypass valve 55A can also be configured to move axially without oscillating, rather than changing its posture relative to the turbine housing 5.

[0056] also, Figure 1 This indicates that the opening 111 of the waste gas bypass valve flow path 110, which is opened and closed by the waste gas bypass valve 55, is closed by the waste gas bypass valve 55. Additionally, Figure 3 This indicates that opening 111 is open.

[0057] Additionally, for example in Figure 1 , Figure 3 The figures shown below illustrate the position of the swing center Cv of the waste gas bypass valve 55, but the position of the swing center Cv is not limited to the position shown in each figure.

[0058] In several embodiments of the turbine 30, such as Figure 1 , Figure 3 As shown in the figures below, the exhaust gas bypass valve flow path 110 is configured to connect the vortex flow path 7a formed inside the turbine housing 5 and the region in the turbine impeller housing 53 upstream of the trailing edge 37 of the plurality of blades 33. More specifically, the exhaust gas bypass valve flow path 110 in several embodiments includes a connecting portion 120, which takes the opening 57 formed on the inner surface 51 of the housing 5 opposite to the leading end (top) 34 of the blades 33 as its downstream end. The connecting portion 120 in several embodiments connects the exhaust gas bypass valve flow path 110 and the turbine impeller housing 53. Furthermore, details of the connecting portion 120 will be described later.

[0059] In a typical turbocharger, the exhaust gas bypass valve path within the turbine is configured to direct exhaust gas flow downstream of the turbine in order to bypass the turbine impeller blades. Therefore, when exhaust gas flows through the bypass valve path to bypass excess exhaust gas exceeding the turbine's throughput, the exhaust gas flowing through the bypass valve path does not contribute to increasing the turbine's output.

[0060] In contrast, according to several embodiments of the turbine 30, the exhaust gas bypass valve flow path 110 is configured to guide the exhaust gas flowing through it to a region in the turbine impeller housing 53 upstream of the trailing edge 37 of the plurality of blades 33. Thus, the exhaust gas within the exhaust gas bypass valve flow path 110 flows towards the plurality of blades 33 of the turbine impeller 3, and therefore, the energy of the exhaust gas can be recovered as the kinetic energy of the turbine impeller 3. Therefore, power recovery from the exhaust gas flowing through the exhaust gas bypass valve flow path 110 is possible, thereby increasing the output of the turbine 30 when the exhaust gas is bypassed to the exhaust gas bypass valve flow path 110.

[0061] In a typical turbine in a turbocharger, there is a gap between the tip 34 of the blade 33 and the inner surface 51 of the housing 5, from which leakage flow (tip leakage) is generated, affecting the flow field and performance in the turbomachinery.

[0062] In the turbine of a turbocharger, the upstream end of the exhaust gas bypass valve flow path is typically located midway through the vortex flow path 7a or upstream of the vortex flow path 7a, in a flow path that is radially outward compared to the turbine impeller 3. Therefore, in several embodiments of the turbine 30, in order to connect the exhaust gas bypass valve flow path 110 to the turbine impeller housing space 53, the downstream end of the exhaust gas bypass valve flow path 110, i.e., the downstream end of the connecting portion 120 in several embodiments, is located on the inner surface 51 of the housing 5 opposite to the tip 34 of the blade 33. Therefore, according to several embodiments of the turbine 30, when the exhaust gas flowing through the exhaust gas bypass valve flow path 110 is guided to the turbine impeller housing space 53, it flows from the inner surface 51 of the housing 5 to the tip 34, thus hindering the aforementioned tip leakage flow and suppressing tip leakage. As a result, the efficiency of the turbine 30 is improved, and therefore, the output of the turbine 30 can be increased.

[0063] According to several embodiments of the turbocharger 1, the turbocharger 1 of several embodiments includes a turbine 30 of several embodiments, thus enabling the turbocharger 1 to improve the partial load performance of the turbine 30.

[0064] In several embodiments of the turbine 30, for example, Figure 3 As shown, the exhaust bypass valve flow path 110 can also be configured to connect the vortex flow path 7a and the region in the turbine impeller housing space 53 that is upstream of the trailing edge 37 of the plurality of blades 33 and downstream of the throat 35.

[0065] Typically, the turbine's throughput is determined based on the flow path area of ​​the throat. Therefore, when the exhaust gas bypass valve flow path 110 is connected to a region upstream of the throat 35, the throughput in the turbine 30 may be reduced due to the influence of exhaust gas flowing into the region upstream of the throat 35 via the exhaust gas bypass valve flow path 110.

[0066] Therefore, as with the turbine 30 in several embodiments, by connecting the exhaust gas bypass valve flow path 110 to the downstream region of the throat 35, even if the exhaust gas flowing through the exhaust gas bypass valve flow path 110 flows into the turbine impeller housing 53, the impact on the throughput of the turbine 30 can be suppressed. Furthermore, by connecting the exhaust gas bypass valve flow path 110 to the downstream region of the throat 35, compared to connecting the exhaust gas bypass valve flow path 110 to the upstream region of the throat 35, the exhaust gas can be effectively discharged to the downstream side of the turbine 30 via the exhaust gas bypass valve flow path 110.

[0067] (The case where turbine impeller 3 has short blades 133)

[0068] Figure 4 This is a schematic cross-section of a turbine 30 in another embodiment.

[0069] In several embodiments of the turbine 30, for example, Figure 4 As shown, the turbine impeller 3 may also have a plurality of short blades 133 disposed between the plurality of blades 33, wherein the trailing edge 137 of each of the plurality of short blades 133 is located on the side closer to the leading edge 36 than the trailing edge 37 of each of the plurality of blades 33. Moreover, in several embodiments of the turbine 30, the exhaust gas bypass valve flow path 110 may also be configured to connect the vortex flow path 7a and the region in the turbine impeller housing space 53 that is upstream of the trailing edge 37 of the plurality of blades 33 and downstream of the trailing edge 137 of the short blades 133.

[0070] If a throat 35 exists in the region containing the short blade 133 within the flow path formed between two circumferentially adjacent blades 33, the waste gas bypass valve flow path 110 is connected to a region in the turbine impeller housing 53 that is upstream of the trailing edge 37 of the plurality of blades 33 and downstream of the trailing edge 137 of the short blade 133, thereby connecting the waste gas bypass valve flow path 110 to the region downstream of the throat 35. Therefore, even if waste gas flowing through the waste gas bypass valve flow path 110 flows into the turbine impeller housing 53, the impact on the throughput of the turbine 30 can be suppressed. Furthermore, by connecting the waste gas bypass valve flow path 110 to the region downstream of the trailing edge 137 of the short blade 133, compared to connecting the waste gas bypass valve flow path 110 to the region upstream of the trailing edge 137 of the short blade 133, the waste gas can be effectively discharged to the downstream side of the turbine 30 via the waste gas bypass valve flow path 110. In addition, because the turbine impeller 3 has multiple short blades 133, the performance of the turbine 30 can be improved even when the exhaust gas does not flow into the exhaust gas bypass valve flow path 110.

[0071] (Connecting portion 120 in several embodiments)

[0072] Figure 5A It is a schematic representation. Figure 3 An example of a V-V view section in the diagram.

[0073] Figure 5B It is a schematic representation. Figure 3 Another example of a V-V view section in the diagram.

[0074] Figure 5C It is a schematic representation. Figure 3 Another example of a V-V view section in the diagram.

[0075] Figure 5D It is a schematic representation. Figure 3 Another example of a V-V view section in the diagram.

[0076] Figure 5E It is a schematic representation. Figure 3 Another example of a V-V view section in the diagram.

[0077] Figure 5F It is a schematic representation. Figure 3 Another example of a V-V view section in the diagram.

[0078] It should be noted that, in Figures 5A to 5F The description of turbine impeller 3 is omitted in the text.

[0079] In several implementations, such as Figure 5A and Figure 5B As shown, the connecting portion 120 may also include a plurality of connecting holes 121, 122 arranged circumferentially spaced apart.

[0080] Therefore, the exhaust gas in the exhaust gas bypass valve flow path 110 can flow from multiple connecting holes 121, 122 to multiple blades 33 of the turbine impeller 3, and the flow rate of the exhaust gas blown out from the multiple connecting holes 121, 122 can be ensured.

[0081] Figure 5A and Figure 5B Each of the plurality of connecting holes 121, 122 shown can also be inclined radially in a manner that, as it moves toward the radially inward side, it moves toward the downstream side of the rotation direction R of the turbine impeller 3.

[0082] For example, for Figure 5A For each of the plurality of connecting holes 121 shown, the cross-sectional area of ​​the flow path from the upstream end 121a to the downstream end 121b is constant.

[0083] For example, for Figure 5B For each of the plurality of connecting holes 122 shown, the flow path cross-sectional area gradually increases from the upstream end 122a toward the downstream end 122b.

[0084] In addition, Figure 5A and Figure 5B Among the multiple connecting holes 121 and 122 shown, the shape of the flow path cross-section when viewed from the upstream end 121a and 122a toward the downstream end 121b and 122b can be rectangular, circular, or a polygon other than a rectangle. Alternatively, the shape of the flow path cross-section can also be an ellipse with a major axis extending circumferentially.

[0085] Figure 5A and Figure 5B The circumferential spacing of the multiple connecting holes 121, 122 shown can be equal or unequal. Furthermore, Figure 5A and Figure 5BThe circumferential spacing and number of the multiple connecting holes 121, 122 shown can also be set in a way that will not cause the blade 33 to vibrate due to the exhaust gas blown out from the connecting holes 121, 122.

[0086] In several implementations, such as Figures 5C to 5E As shown, the connecting portion 120 may also include a groove 125 extending circumferentially.

[0087] Therefore, by allowing the exhaust gas in the exhaust gas bypass valve flow path 110 to flow from the circumferentially extending groove 125 to the multiple blades 33 of the turbine impeller 3, the vibration of the blades 33 can be suppressed, thereby improving the reliability of the turbine 30.

[0088] It should be noted that the slot 125 in several embodiments can be, for example, as follows: Figure 5C The groove 125 shown can be divided into multiple sections along the circumference, or it can be a single groove continuously arranged throughout the entire circumference.

[0089] In several implementations, such as Figure 5D and Figure 5E As shown, a plurality of nozzle components 131, 132 may also be provided in the groove 125 at circumferential intervals. These nozzle components 131, 132 are used to guide the exhaust gas through the groove 125 so that the exhaust gas flows towards the downstream side of the rotation direction R of the turbine impeller 3 in a radially inward direction.

[0090] Therefore, by using multiple nozzle components 131, 132 to guide the exhaust gas as described above, the exhaust gas can be effectively directed into the turbine impeller housing space 53. This further improves the output of the turbine 30 when the exhaust gas is bypassed to the exhaust gas bypass valve flow path 110.

[0091] For example, Figure 5D The plurality of nozzle components 131 shown may each be axial, for example. Figure 5D The nozzle component 131 is a plate-shaped part whose thickness direction is the same as the paper depth direction. As a result, the manufacturing cost of the nozzle component 131 can be reduced.

[0092] In addition, for example, Figure 5E Each of the multiple nozzle components 132 shown can, for example, be a component with a blade-like shape. This allows exhaust gas to flow effectively into the turbine impeller housing 53.

[0093] In several implementations, such as Figure 5F As shown, the connecting portion 120 can also have a shape that is narrow at the front and wide at the back. That is, in several embodiments, such as Figure 5F As shown, the connecting portion 120 may also have a nozzle portion 140, which has a shape that is narrow at the front and wide at the back.

[0094] Typically, when the waste gas bypass valves 55 and 55A are open and waste gas flows into the waste gas bypass valve flow path 110, the pressure ratio of the turbine 30 is usually high. Therefore, the flow velocity of the waste gas passing through the connecting portion 120 is very fast. Thus, as described above, by making the connecting portion 120 a shape with a narrow front and wide rear, similar to a Laval nozzle, the energy of the waste gas blown out of the connecting portion 120 can be effectively converted into the kinetic energy of the turbine impeller 3. This further improves the output of the turbine 30 when waste gas is bypassed to the waste gas bypass valve flow path 110. Furthermore, it is relatively easy to machine the connecting portion 120 into a shape with a narrow front and wide rear, thus reducing manufacturing costs.

[0095] In addition, such as Figures 5C-5E As shown, when the connecting portion 120 includes a groove 125 extending in the circumferential direction, the width of the groove 125 along the axial direction can be changed according to the radial position so that the groove 125 has a shape that is narrow at the front and wide at the end when viewed in the circumferential direction.

[0096] Figure 6 This is a schematic cross-sectional view of a turbine 30 according to another embodiment.

[0097] In several implementations, for example, Figure 6 As shown, the exhaust bypass valve flow path 110 may also include a vortex section 150 configured such that its cross-sectional area decreases towards the downstream side of the rotation direction R of the turbine impeller 3, and the vortex section 150 is connected to the turbine impeller receiving space 53 via the aforementioned groove 125.

[0098] Therefore, by utilizing the vortex portion 150 of the exhaust gas bypass valve flow path 110 to guide the exhaust gas circumferentially, the difference in circumferential position of the exhaust gas flow rate flowing into the turbine impeller housing space 53 via the aforementioned groove 125 can be suppressed. As a result, the output of the turbine 30 when the exhaust gas is bypassed to the exhaust gas bypass valve flow path 110 can be further improved.

[0099] (In the case of having bypass section 160)

[0100] Figure 7 This is a schematic cross-sectional view of a turbine 30 according to another embodiment. Figure 7 This indicates that opening 111 is open.

[0101] Figures 8A to 8C This is a schematic cross-sectional view of a turbine 30 according to another embodiment.

[0102] Figure 8A This indicates that opening 111 is closed by the waste gas bypass valve 55.

[0103] Figure 8B This indicates a small opening degree for the waste gas bypass valve 55.

[0104] Figure 8C This indicates that the opening degree of the waste gas bypass valve 55 is relatively large.

[0105] Figures 9A to 9C This is a schematic cross-sectional view of a turbine 30 according to another embodiment.

[0106] Figure 9A This indicates that opening 111 is closed by the waste gas bypass valve 55A.

[0107] Figure 9B This indicates a situation where the opening degree of the waste gas bypass valve 55A is relatively small.

[0108] Figure 9C This indicates that the opening degree of the waste gas bypass valve 55A is relatively large.

[0109] like Figure 7 , Figures 8A to 8C and Figures 9A to 9C As shown, in several embodiments of the turbine 30, a bypass section 160 may also be provided, which is configured to connect the exhaust gas bypass valve flow path 110 and the discharge flow path 171 formed on the downstream side of the turbine impeller 3.

[0110] This increases the flow rate of exhaust gas passing through the exhaust gas bypass valve flow path 110. Furthermore, even if the amount of exhaust gas supplied exceeds the turbine power required to drive the compressor 40, the excess exhaust gas can be bypassed outside the turbine 30. Therefore, the output of the turbine 30 when exhaust gas is bypassed to the exhaust gas bypass valve flow path 110 can be improved, and over-rotation of the turbine 30 can be suppressed, thereby improving the reliability of the turbine 30.

[0111] More specifically, in Figure 7 In the turbine 30 shown, the upstream end 161 of the bypass section 160 is connected to a region downstream of the opening 111 in the exhaust bypass valve flow path 110. The downstream end 163 of this bypass section 160 is connected to an exhaust flow path 171 formed on the turbine impeller 3, downstream of the trailing edge 37 of the plurality of blades 33. Figure 7 In the turbine 30 shown, when the exhaust bypass valve 55 opens the opening 111, the exhaust gas flowing out of the opening 111 flows into the connecting part 120 and the bypass part 160.

[0112] exist Figure 7 In the turbine 30 shown, as described above, the exhaust gas flowing into the connecting part 120 flows from the connecting part 120 into the turbine impeller receiving space 53 and flows to the multiple blades 33 of the turbine impeller 3.

[0113] exist Figure 7In the turbine 30 shown, the exhaust gas flowing into the bypass section 160 does not flow into the turbine impeller housing space 53 from the bypass section 160, but flows directly into the discharge flow path 171.

[0114] like Figure 7 , Figures 8A to 8C and Figures 9A to 9C As shown, in several embodiments of the turbine 30, the connecting portion 120, which connects the exhaust gas bypass valve flow path 110 and the turbine impeller receiving space 53, can be located upstream of the opening 111 in the axial direction. The bypass portion 160 can be located downstream of the opening 111 in the axial direction.

[0115] For example, when the opening degree of the waste gas bypass valves 55 and 55A is small, and the axial position of the gap between the waste gas bypass valves 55 and 55A and the opening 111 is located upstream of the upstream end 161 of the bypass section 160, the waste gas flowing out of the opening 111 is blocked from flowing to the bypass section 160 by the waste gas bypass valves 55 and 55A. Therefore, the waste gas flowing out of the opening 111 flows towards the connecting section 120. That is, when the opening degree of the waste gas bypass valves 55 and 55A is small, the waste gas flowing out of the opening 111 mainly flows through the connecting section 120.

[0116] When the opening degree of the waste gas bypass valves 55 and 55A is large, the waste gas flowing out of the opening 111 is less likely to be obstructed by the waste gas bypass valves 55 and 55A and flows to the bypass section 160 side, thus easily flowing to the bypass section 160 side. That is, for example, when the opening degree of the waste gas bypass valves 55 and 55A is large, for example, Figure 7 , Figures 8A to 8C and Figures 9A to 9C When the upstream end 161 of the bypass section 160 is located within the axial position range of the gap between the waste gas bypass valves 55, 55A and the opening 111, the waste gas flowing out of the opening 111 flows not only to the connecting section 120, but also to the bypass section 160.

[0117] Therefore, the distribution ratio of exhaust gas flowing through the connecting section 120 and the bypass section 160 can be adjusted according to the opening degree of the exhaust gas bypass valves 55 and 55A. As a result, the output of the turbine 30 when the exhaust gas is bypassed to the exhaust gas bypass valve flow path 110 can be further improved, and the over-rotation of the turbine 30 can be suppressed to improve the reliability of the turbine 30.

[0118] In addition, for example, Figures 8A to 8C As shown, the waste gas bypass valve 55, which can be oscillatingly supported, may also have a front end 56 located at the position furthest from the oscillation center Cv of the waste gas bypass valve 55. For example Figures 8A to 8C The turbine 30 shown may also have an opposing portion 115, which is opposed to the front end 56 of the exhaust bypass valve 55 within the exhaust bypass valve flow path 110 via a small gap. For example, in Figures 8A to 8CIn the turbine 30 shown, the upstream end 161 of the bypass section 160 may also be located on the axial downstream side of the opposing section 115.

[0119] exist Figures 8A to 8C In the turbine 30 shown, in Figure 8A When the exhaust bypass valve 55 is closed at opening 111 as shown, the exhaust gas will not flow to the exhaust bypass valve flow path 110 which is downstream of opening 111.

[0120] exist Figures 8A to 8C In the turbine 30 shown, considering Figure 8B As shown, the exhaust bypass valve 55 has a small opening, and at least a portion of the front end 56 of the exhaust bypass valve 55 and the opposing portion 115 are in a position that repeats along the axial direction, that is, at least a portion of the front end 56 is located axially upstream of the upstream end 161 of the bypass portion 160. In this case, at least a portion of the front end 56 of the exhaust bypass valve 55 repeats along the axial direction with the opposing portion 115, so exhaust gas can hardly flow through the gap between the front end 56 of the exhaust bypass valve 55 and the opposing portion 115. Therefore, the exhaust gas flowing out of the opening 111 flows into the connecting portion 120, except for a very small amount that flows through the gap.

[0121] exist Figures 8A to 8C In the turbine 30 shown, considering Figure 8C As shown, the exhaust bypass valve 55 has a large opening, and the front end 56 of the exhaust bypass valve 55 is located downstream of the opposing portion 115 along the axial direction. That is, at least a portion of the upstream end 161 of the bypass portion 160 is located axially upstream of the front end 56 of the exhaust bypass valve 55. In this case, the exhaust gas flowing out of the opening 111 flows into the connecting portion 120 and the bypass portion 160.

[0122] In addition, for example, Figures 9A to 9C As shown, the exhaust bypass valve 55A is configured to move axially without oscillating, but without changing its posture relative to the turbine housing 5. It can also be configured to close or open the opening 111 by moving axially. Figures 9A to 9C The waste gas bypass valve 55A shown may also have a front end 56A located radially inside the waste gas bypass valve 55A. For example Figures 9A to 9C The turbine 30 shown may also have an opposing portion 115A that is positioned within the exhaust bypass valve flow path 110 and faces the front end 56A of the exhaust bypass valve 55A via a small gap. For example, in Figures 9A to 9C In the turbine 30 shown, the upstream end 161 of the bypass section 160 may also be located on the axial downstream side of the opposing section 115A.

[0123] exist Figures 9A to 9C In the turbine 30 shown, in Figure 9AWhen the exhaust bypass valve 55A closes the opening 111 as shown, exhaust gas will not flow into the exhaust bypass valve flow path 110, which is downstream of the opening 111.

[0124] exist Figures 9A to 9C In the turbine 30 shown, considering Figure 9B As shown, the waste gas bypass valve 55A has a small opening, and at least a portion of the front end 56A of the waste gas bypass valve 55A and the opposing portion 115A are in a position that repeats along the axial direction, that is, at least a portion of the front end 56A is located axially upstream of the upstream end 161 of the bypass portion 160. In this case, at least a portion of the front end 56A of the waste gas bypass valve 55A repeats along the axial direction with the opposing portion 115, so the waste gas can hardly flow through the gap between the front end 56A and the opposing portion 115A of the waste gas bypass valve 55A. Therefore, the waste gas flowing out of the opening 111 flows into the connecting portion 120, except for a very small amount that flows through the gap.

[0125] exist Figures 9A to 9C In the turbine 30 shown, considering Figure 9C As shown, the waste gas bypass valve 55A has a large opening, and its front end 56A is located downstream of the opposing portion 115A along the axial direction. Specifically, at least a portion of the upstream end 161 of the bypass portion 160 is located axially upstream of the front end 56A of the waste gas bypass valve 55A. In this case, waste gas flowing out of the opening 111 flows into the connecting portion 120 and the bypass portion 160.

[0126] In addition, such as Figures 8A to 8C and Figures 9A to 9C As shown, the downstream region 160D of the bypass section 160 can be tilted toward the axial downstream side, and the exhaust gas discharged from the bypass section 160 flows toward the axial downstream side along the flow path wall 172 that forms the discharge flow path 171.

[0127] As mentioned above, typically, when the exhaust bypass valve 55A is open and exhaust gas flows into the exhaust bypass valve flow path 110, the pressure ratio of the turbine 30 is usually high. Therefore, the flow velocity of the exhaust gas flowing through the bypass section 160 is relatively high. Therefore, by configuring the bypass section 160 such that the exhaust gas discharged from the bypass section 160 flows axially downstream along the flow path wall 172, the boundary layer in the turbine diffuser (not shown) connected to the downstream side of the discharge flow path 171 by the exhaust gas discharged from the bypass section 160 can be given a certain amount of motion. As a result, flow stripping in the turbine diffuser can be suppressed.

[0128] This disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0129] For example, the contents described in the above embodiments can be understood as follows.

[0130] (1) The turbine 30 of at least one embodiment of the present disclosure includes: a turbine impeller 3 having a plurality of blades 33; a turbine housing 5 having a turbine impeller housing space 53 formed therein to accommodate the turbine impeller 3; and exhaust gas bypass valves 55 and 55A for controlling the exhaust gas flow rate through an exhaust gas bypass valve flow path 110 formed inside the turbine housing 5. The exhaust gas bypass valve flow path 110 is configured to connect a vortex flow path 7a formed inside the turbine housing 5 and a region in the turbine impeller housing space 53 upstream of the trailing edge 37 of the plurality of blades 33.

[0131] According to the configuration described in (1) above, the exhaust gas bypass valve flow path 110 is configured to guide the exhaust gas flowing through it to a region upstream of the trailing edge 37 of the plurality of blades 33 in the turbine impeller housing space 53. Thus, the exhaust gas in the exhaust gas bypass valve flow path 110 flows towards the plurality of blades 33 of the turbine impeller 3, thereby enabling the recovery of the energy of the exhaust gas as the kinetic energy of the turbine impeller 3. Therefore, since the power from the exhaust gas flowing through the exhaust gas bypass valve flow path 110 can be recovered, the output of the turbine 30 when the exhaust gas is bypassed to the exhaust gas bypass valve flow path 110 can be increased. Furthermore, by guiding the exhaust gas flowing through the exhaust gas bypass valve flow path 110 to the turbine impeller housing space 53, tip leakage of the exhaust gas in the gap between the tips 34 of the plurality of blades 33 and the turbine housing 5 can be suppressed. Therefore, the efficiency of the turbine 30 is improved, and thus, the output of the turbine 30 can be increased.

[0132] (2) In several embodiments, according to the configuration described in (1) above, the exhaust bypass valve flow path 110 may also be configured to connect the vortex flow path 7a and the region in the turbine impeller housing space 53 that is upstream of the trailing edge 37 of the plurality of blades 33 and downstream of the throat 35.

[0133] As mentioned above, the turbine's throughput is typically determined based on the flow path area of ​​the throat. Therefore, when the exhaust gas bypass valve flow path 110 is connected to a region upstream of the throat 35, the turbine 30's throughput may decrease due to the influence of exhaust gas flowing into the region upstream of the throat 35 via the exhaust gas bypass valve flow path 110.

[0134] Therefore, with the configuration described in (2) above, by connecting the exhaust gas bypass valve flow path 110 to the downstream region of the throat 35, even if the exhaust gas flowing through the exhaust gas bypass valve flow path 110 flows into the turbine impeller housing space 53, the impact on the throughput of the turbine 30 can be suppressed. Furthermore, by connecting the exhaust gas bypass valve flow path 110 to the downstream region of the throat 35, compared to connecting the exhaust gas bypass valve flow path 110 to the upstream region of the throat 35, the exhaust gas can be effectively discharged to the downstream side of the turbine 30 via the exhaust gas bypass valve flow path 110.

[0135] (3) In several embodiments, according to the configuration described in (1) or (2) above, the turbine impeller 3 may further have a plurality of short blades 133 disposed between the plurality of blades 33, wherein the plurality of short blades 133 are configured such that the trailing edge 137 of each of the plurality of short blades 133 is located on the side of the leading edge 36 relative to the trailing edge 37 of the plurality of blades 33. The exhaust gas bypass valve flow path 110 may also be configured to connect the vortex flow path 7a and the region in the turbine impeller housing space 53 that is upstream of the trailing edge 37 of the plurality of blades 33 and downstream of the trailing edge 137 of the short blades 133.

[0136] If a throat 35 exists in the region where the short blade 133 is located within the flow path formed between two adjacent blades 33 in the circumferential direction, then by adopting the structure described above (3), the exhaust gas bypass valve flow path 110 is connected to the region downstream of the throat 35. Therefore, even if the exhaust gas flowing through the exhaust gas bypass valve flow path 110 flows into the turbine impeller housing space 53, the influence on the turbine's throughput can be suppressed. In addition, by connecting the exhaust gas bypass valve flow path 110 to the region downstream of the trailing edge 137 of the short blade 133, compared to the case where the exhaust gas bypass valve flow path 110 is connected to the region upstream of the trailing edge 137 of the short blade 133, the exhaust gas can be effectively discharged to the downstream side of the turbine 30 via the exhaust gas bypass valve flow path 110. Furthermore, since the turbine impeller 3 has multiple short blades 133, the performance of the turbine 30 can be improved even when the exhaust gas does not flow to the exhaust gas bypass valve flow path 110.

[0137] (4) In several embodiments, according to any of the configurations in (1) to (3) above, the connecting portion 120 that connects the exhaust gas bypass valve flow path 110 and the turbine impeller receiving space 53 may include a plurality of connecting holes 121, 122 arranged circumferentially spaced apart.

[0138] According to the above configuration (4), the exhaust gas in the exhaust bypass valve flow path 110 can flow from multiple connecting holes 121, 122 to multiple blades 33 of the turbine impeller 3, and the flow rate of the exhaust gas blown out from the multiple connecting holes 121, 122 can be ensured.

[0139] (5) In several embodiments, according to any of the configurations in (1) to (3) above, the connecting portion 120 that connects the exhaust gas bypass valve flow path and the turbine impeller receiving space 53 of 110 may include a groove 125 extending in the circumferential direction.

[0140] According to the above configuration (5), by causing the exhaust gas in the exhaust gas bypass valve flow path 110 to flow from the circumferentially extending groove 125 to the multiple blades 33 of the turbine impeller 3, the vibration of the blades 33 can be suppressed, thereby improving the reliability of the turbine 30.

[0141] (6) In several embodiments, according to the configuration of (5) above, the exhaust gas bypass valve flow path 110 may include a vortex portion 150 configured such that the cross-sectional area decreases toward the downstream side of the rotation direction R of the turbine impeller 3, the vortex portion 150 being connected to the turbine impeller receiving space 53 via the groove 125.

[0142] According to the configuration described in (6) above, by using the vortex section 150 to guide the exhaust gas circumferentially, the difference in the circumferential position of the exhaust gas flow rate flowing into the turbine impeller housing space 53 via the groove 125 can be suppressed. As a result, the output of the turbine 30 when the exhaust gas is bypassed to the exhaust gas bypass valve flow path 110 can be further improved.

[0143] (7) In several embodiments, according to the configuration of (5) or (6) above, a plurality of nozzle components 131, 132 are arranged circumferentially spaced in the groove 125, the plurality of nozzle components 131, 132 being used to guide the exhaust gas through the groove 125 so that the exhaust gas flows toward the downstream side of the rotation direction R of the turbine impeller 3 toward the radially inward side.

[0144] According to the configuration described in (7), by using multiple nozzle components 131, 132 to guide the exhaust gas as described above, the exhaust gas can be effectively directed into the turbine impeller housing space 53. As a result, the output of the turbine 30 when the exhaust gas is bypassed to the exhaust gas bypass valve flow path 110 can be further improved.

[0145] (8) In several embodiments, according to any of the configurations in (4) to (7) above, the connecting portion 120 may also have a shape that is narrow at the front and wide at the back.

[0146] Normally, when the exhaust bypass valves 55 and 55A are open and exhaust gas flows through the exhaust bypass valve flow path 110, the pressure ratio of the turbine 30 is usually high. Therefore, the flow velocity of the exhaust gas flowing through the connecting part 120 is very fast. Therefore, according to the configuration described above (8), since the connecting part 120 is designed with a narrow front and wide rear, i.e., a Laval nozzle shape, the energy of the exhaust gas blown out of the connecting part 120 can be effectively converted into the kinetic energy of the turbine impeller 3. As a result, the output of the turbine 30 when the exhaust gas is bypassed to the exhaust bypass valve flow path 110 can be further improved. In addition, it is relatively easy to process the connecting part 120 into a narrow front and wide rear shape, so manufacturing costs can be suppressed.

[0147] (9) In several embodiments, according to any of the configurations in (1) to (8) above, a bypass section 160 may be further provided, which is configured to connect the exhaust gas bypass valve flow path 110 and the discharge flow path 171 formed on the downstream side of the turbine impeller 3.

[0148] According to the configuration described in (9) above, the flow rate of exhaust gas flowing through the exhaust gas bypass valve flow path 110 can be increased. Furthermore, even if the amount of exhaust gas supplied exceeds the amount required for the turbine power needed to drive the compressor 40, the remaining exhaust gas can be bypassed outside the turbine 30. Therefore, the output of the turbine 30 when the exhaust gas is bypassed to the exhaust gas bypass valve flow path 110 can be improved, and over-rotation of the turbine 30 can be suppressed, thereby improving the reliability of the turbine 30.

[0149] (10) In several embodiments, according to the configuration described in (9) above, the exhaust gas bypass valve flow path 110 may include an opening 111 that is opened and closed by the exhaust gas bypass valve 55. The exhaust gas bypass valve 55 may be a swing valve, the radially outer position of which is swingably supported on the turbine housing 5. The connecting portion 120 that connects the exhaust gas bypass valve flow path 110 and the turbine impeller receiving space 53 may be located upstream of the opening 111 in the axial direction. The bypass portion 160 may be located downstream of the opening 111 in the axial direction.

[0150] According to the above configuration (10), when the opening degree of the waste gas bypass valve 55 is small, the waste gas flowing out from the opening 111 is blocked by the waste gas bypass valve 55 from flowing to the bypass section 160 side, and therefore flows to the connecting section 120 side. Therefore, when the opening degree of the waste gas bypass valve 55 is small, the waste gas flowing out from the opening 111 mainly flows through the connecting section 120.

[0151] When the exhaust gas bypass valve 55 is open to a large degree, the exhaust gas flowing out of the opening 111 is not easily obstructed by the exhaust gas bypass valve 55 and flows to the bypass section 160 side, so it easily flows to the bypass section 160 side. Therefore, when the exhaust gas bypass valve 55 is open to a large degree, the exhaust gas flowing out of the opening 111 flows not only to the connecting section 120, but also to the bypass section 160.

[0152] Therefore, the distribution ratio of exhaust gas flowing through the connecting section 120 and the bypass section 160 can be adjusted by the opening degree of the exhaust gas bypass valve 55. As a result, the output of the turbine 30 when the exhaust gas is bypassed to the exhaust gas bypass valve flow path 110 can be further improved, and the over-rotation of the turbine can be suppressed to improve the reliability of the turbine 30.

[0153] (11) In several embodiments, according to the configuration described in (9) above, the exhaust gas bypass valve flow path 110 may include an opening 111 that is opened and closed by the exhaust gas bypass valve 55A. The exhaust gas bypass valve 55A may also be configured to be axially movable. The connecting portion 120 that connects the exhaust gas bypass valve flow path 110 and the turbine impeller receiving space 53 may be located upstream of the opening 111 in the axial direction. The bypass portion 160 may be located downstream of the opening 111 in the axial direction.

[0154] According to the configuration described in (11), when the opening degree of the waste gas bypass valve 55A is small, the waste gas flowing out from the opening 111 is blocked from flowing to the bypass section 160 by the waste gas bypass valve 55A, and therefore flows to the connecting section 120. Therefore, when the opening degree of the waste gas bypass valve 55A is small, the waste gas flowing out from the opening 111 mainly flows through the connecting section 120.

[0155] When the exhaust gas bypass valve 55A is open to a large degree, the exhaust gas flowing out of the opening 111 is not easily obstructed by the exhaust gas bypass valve 55A and flows to the bypass section 160 side, so it easily flows to the bypass section 160 side. Therefore, when the exhaust gas bypass valve 55A is open to a large degree, the exhaust gas flowing out of the opening 111 flows not only to the connecting section 120, but also to the bypass section 160.

[0156] Therefore, the distribution ratio of exhaust gas flowing through the connecting section 120 and the bypass section 160 can be adjusted by the opening degree of the exhaust gas bypass valve 55A. As a result, the output of the turbine 30 when the exhaust gas is bypassed to the exhaust gas bypass valve flow path 110 can be further improved, and the over-rotation of the turbine can be suppressed to improve the reliability of the turbine 30.

[0157] (12) The turbocharger 1 of at least one embodiment of the present disclosure includes a turbine 30 configured in any of (1) to (11) above.

[0158] Based on the above (12) configuration, a turbocharger 1 that improves the partial load performance of the turbine 30 can be provided.

[0159] Explanation of reference numerals in the attached figures

[0160] 1 turbocharger

[0161] 3 turbine impellers

[0162] 5. Casing (Turbine Housing)

[0163] 7. Vortex section

[0164] 7a Vortex Flow Path

[0165] 30 Turbo

[0166] 33 blades (moving blades)

[0167] 34. Front end (top)

[0168] 35 Throat

[0169] 36 front edge

[0170] 37 posterior edge

[0171] 53 Turbine impeller housing space

[0172] 55, 55A Exhaust Gas Bypass Valve

[0173] 110 Exhaust Gas Bypass Valve Flow Path

[0174] 111 opening

[0175] 120 connecting parts

[0176] 121 and 122 connecting holes

[0177] 125 slot

[0178] Nozzle components 131 and 132

[0179] 133 short blade

[0180] 137 trailing edge

[0181] 140 Nozzle Section

[0182] 160 bypass section

[0183] 171 discharge flow path

Claims

1. A turbine, comprising: A turbine impeller, which has multiple blades; The turbine housing forms a turbine impeller housing space within it to accommodate the turbine impeller; An exhaust gas bypass valve, used to control the exhaust gas flow rate through an exhaust gas bypass valve path formed inside the turbine housing, is characterized in that... The exhaust gas bypass valve flow path is configured to connect the vortex flow path formed inside the turbine housing and the region in the turbine impeller housing that is upstream of the trailing edge of the plurality of blades. The turbine includes a bypass section configured to connect the exhaust gas bypass valve flow path and a discharge flow path formed on the downstream side of the turbine impeller. The waste gas bypass valve flow path includes an opening that can be opened and closed by the waste gas bypass valve. The exhaust gas bypass valve is configured to adjust the distribution ratio between the flow rate of exhaust gas from the opening into the region upstream of the trailing edge of the plurality of blades in the turbine impeller housing and the flow rate of exhaust gas from the opening flowing into the discharge path via the bypass section.

2. The turbine according to claim 1, wherein, For the aforementioned waste gas bypass valve At an opening less than a specified opening, exhaust gas from the opening is allowed to flow into a region upstream of the trailing edges of the plurality of blades within the turbine impeller housing, while hindering the flow of exhaust gas from the opening into the discharge path via the bypass. At an opening greater than the specified opening degree, exhaust gas from the opening is allowed to flow into a region upstream of the trailing edge of the plurality of blades in the turbine impeller housing, and exhaust gas from the opening is allowed to flow into the discharge path via the bypass.

3. The turbine according to claim 1 or 2, wherein, The exhaust gas bypass valve flow path is configured to connect the vortex flow path and the region upstream of the trailing edge of the plurality of blades in the turbine impeller housing space, which is downstream of the throat.

4. The turbine according to claim 1 or 2, wherein, The turbine impeller also has a plurality of short blades disposed between the plurality of blades, wherein the trailing edge of each of the plurality of short blades is located on the leading edge side compared to the trailing edge of each of the plurality of blades. The exhaust gas bypass valve flow path is configured to connect the vortex flow path and the region in the turbine impeller housing space that is upstream of the trailing edge of the plurality of blades and downstream of the trailing edge of the shorter blade.

5. The turbine according to claim 1 or 2, wherein, The connecting portion that connects the exhaust gas bypass valve flow path and the turbine impeller housing includes a plurality of connecting holes arranged at intervals along the circumference.

6. The turbine according to claim 1 or 2, wherein, The connecting portion that connects the exhaust gas bypass valve flow path and the turbine impeller housing includes a groove extending circumferentially.

7. The turbine according to claim 6, wherein, The exhaust bypass valve flow path includes a vortex portion configured such that its cross-sectional area decreases towards the downstream side of the turbine impeller's rotation direction, and the vortex portion is connected to the turbine impeller receiving space via the slot.

8. The turbine according to claim 6, wherein, It also includes a plurality of nozzle components arranged circumferentially spaced within the groove, which are used to guide the exhaust gas through the groove so that the exhaust gas flows toward the downstream side of the turbine impeller in the direction of rotation as it moves toward the radially inward side.

9. The turbine according to claim 5, wherein, The connecting portion has a shape that is narrow at the front and wide at the back.

10. The turbine according to claim 1 or 2, wherein, The waste gas bypass valve flow path includes an opening that can be opened and closed by the waste gas bypass valve. The exhaust gas bypass valve is composed of a swing valve, which is radially outwardly supported on the turbine housing. The connecting portion that connects the exhaust gas bypass valve flow path and the turbine impeller housing space is located on the upstream side of the axial direction relative to the opening. The bypass portion is located on the downstream side of the axial direction relative to the opening.

11. The turbine according to claim 1 or 2, wherein, The waste gas bypass valve flow path includes an opening that can be opened and closed by the waste gas bypass valve. The waste gas bypass valve is configured to be axially movable. The connecting portion that connects the exhaust gas bypass valve flow path and the turbine impeller housing space is located on the upstream side of the axial direction relative to the opening. The bypass portion is located on the downstream side of the axial direction relative to the opening.

12. A turbocharger comprising the turbine as claimed in claim 1 or 2.

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