Turbine

Abstract

The turbine (T) includes an impeller (2) and a housing (5) that houses the impeller (2). The housing (5) comprises: an inlet in fluid communication with an exhaust port of the engine; a first space (S1) in which the impeller (2) is housed; a second space (S2) located downstream of the first space (S1) in the flow of exhaust gas from the engine; a first flow path (51) that connects the inlet and the first space (S1); and a second flow path (52) that directly connects the inlet and the second space (S2) without connecting the inlet and the first space (S1).

Description

Technical Field

[0001] The present disclosure relates to a turbine. This application claims the benefit of priority based on Japanese Patent Application No. 2022-142055 filed on September 7, 2022, the contents of which are incorporated herein by reference. Background Art

[0002] Sometimes a turbine is arranged in the exhaust flow path of the engine. The impeller of the turbine is rotated by the exhaust gas from the engine. For example, the rotational force of the impeller is used by other devices such as a compressor that pressurizes the intake air of the engine.

[0003] In addition, a catalyst is sometimes provided in the exhaust flow path in order to purify the exhaust gas. When the engine is started, the catalyst is at room temperature. If the catalyst is not heated to a temperature higher than a certain temperature, it will not function well. Therefore, the turbine sometimes includes a bypass flow path in a manner that a part of the exhaust gas bypasses the impeller. When the engine is started, the valve of the bypass flow path is opened so that a part of the exhaust gas does not pass through the impeller but flows into the catalyst. According to such a structure, the temperature of the exhaust gas bypassing the impeller does not decrease, so the catalyst is quickly heated.

[0004] Patent document 1 discloses a turbine including such a bypass flow path. The turbine includes two vortex flow paths. The two vortex flow paths are respectively connected to the turbine wheel fluid. One of the two vortex flow paths is connected to the bypass passage. The bypass passage connects the corresponding vortex flow path to the space downstream of the turbine wheel. According to such a structure, a part of the exhaust gas does not pass through the turbine wheel but flows into the space downstream of the turbine wheel. A sliding valve for opening and closing the bypass passage is provided in the space.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2017-141704 Summary of the invention

[0008] Problems to be solved by the invention

[0009] In the turbine of Patent Document 1, the valve of the bypass flow path may hinder the flow of the main flow and the bypass flow passing through the impeller. Therefore, there is a possibility that the exhaust gas is not effectively guided to the catalyst.

[0010] An object of the present disclosure is to provide a turbine capable of smoothly guiding exhaust gas.

[0011] Means for solving problems

[0012] In order to solve the above-mentioned problems, a turbine according to one embodiment of the present invention comprises: an impeller; and a casing that accommodates the impeller, the casing including: an inlet that is fluidly connected to an exhaust port of an engine; a first space that accommodates the impeller; a second space that is located downstream of the first space in the flow of exhaust gas from the engine; a first flow path that connects the inlet and the first space; and a second flow path that directly connects the inlet and the second space without connecting the inlet and the first space.

[0013] The turbine may include a valve that opens and closes the second flow path at a position upstream of the first space.

[0014] The volume of the second flow path may be smaller than the volume of the first flow path.

[0015] The second flow path may have a spiral shape.

[0016] The turbine may include an exhaust port located downstream of the second space in the flow of the exhaust gas, and the second flow path may be configured to face the exhaust port in the axial direction of the impeller.

[0017] Effects of the Invention

[0018] According to the present disclosure, exhaust gas can be smoothly guided. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic cross-sectional view of a supercharger including a turbine according to an embodiment.

[0020] Figure 2 is Figure 1 A schematic front view of the supercharger viewed from the direction indicated by arrow II.

[0021] Figure 3 Yes means Figure 2 A partial stereogram of the portion surrounded by the dotted line. DETAILED DESCRIPTION

[0022] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The specific dimensions, materials, and numerical values ​​shown in the embodiments are merely examples for easy understanding and do not limit the present disclosure except for the cases specifically described. In addition, in the present specification and the accompanying drawings, for elements having substantially the same function and structure, repeated descriptions are omitted by marking the same reference numerals. In addition, elements that are not directly related to the present disclosure are omitted from the drawings.

[0023] Figure 11 is a schematic cross-sectional view of a supercharger TC equipped with a turbine T according to an embodiment. In the present embodiment, the turbine T is assembled to the supercharger TC. In other embodiments, the turbine T may be assembled to a device other than the supercharger TC, or may be a single unit.

[0024] The supercharger TC includes a shaft 1, a turbine impeller (impeller) 2, and a compressor impeller 3. As described later, the shaft 1, the turbine impeller 2, and the compressor impeller 3 rotate integrally. Therefore, in the present disclosure, the "axial direction", "radial direction", and "circumferential direction" of the shaft 1, the turbine impeller 2, and the compressor impeller 3 can be simply referred to as "axial direction", "radial direction", and "circumferential direction", respectively.

[0025] The supercharger TC includes a bearing housing 4, a turbine housing (housing) 5, and a compressor housing 6. The turbine housing 5 and the first end surface of the bearing housing 4 in the axial direction are connected. Figure 1 The compressor housing 6 is connected to the second end surface of the bearing housing 4 in the axial direction. Figure 1 The middle is the right side end connection.

[0026] The bearing housing 4 includes a bearing hole 4a. The bearing hole 4a extends axially in the bearing housing 4. The bearing hole 4a accommodates a bearing 7. In this embodiment, a semi-floating bearing is shown as an example of the bearing 7. In other embodiments, the bearing 7 may also be a full floating bearing or other radial bearings such as a rolling bearing. The bearing 7 rotatably supports the shaft 1.

[0027] The turbine impeller 2 is disposed at the first end portion of the shaft 1 in the axial direction. Figure 1 The left end is shown in the middle. The turbine impeller 2 rotates integrally with the shaft 1. The turbine impeller 2 is rotatably accommodated in the turbine housing 5.

[0028] The compressor impeller 3 is provided at a second end portion of the shaft 1 on the opposite side to the first end portion in the axial direction. Figure 1 The compressor impeller 3 rotates integrally with the shaft 1. The compressor impeller 3 is rotatably accommodated in the compressor housing 6.

[0029] The compressor housing 6 includes an air inlet 6a at an end surface on the side opposite to the bearing housing 4 in the axial direction. The air inlet 6a is connected to an air filter (not shown). The bearing housing 4 and the compressor housing 6 define a diffusion flow path 60 therebetween. The diffusion flow path 60 has an annular shape around the compressor impeller 3. The diffusion flow path 60 is fluidically connected to the air inlet 6a via the compressor impeller 3.

[0030] The compressor housing 6 includes a scroll flow path 61. The scroll flow path 61 is located radially outward of the diffuser flow path 60. The scroll flow path 61 is in fluid communication with the diffuser flow path 60. The scroll flow path 61 is in fluid communication with an intake port of an engine (not shown). The scroll flow path 61 has a substantially scroll shape.

[0031] In the compressor housing 6 as described above, when the compressor impeller 3 rotates, air is sucked into the compressor housing 6 from the air inlet 6a. The air is accelerated and pressurized by centrifugal force while passing through the compressor impeller 3. The air is further pressurized in the diffuser flow path 60 and the vortex flow path 61. The pressurized air flows out from the outlet not shown in the figure and is guided to the air intake of the engine. In the supercharger TC, the part including the compressor impeller 3 and the compressor housing 6 functions as a centrifugal compressor C.

[0032] The turbine housing 5 includes an exhaust port 5a on the end surface on the side opposite to the bearing housing 4 in the axial direction. The exhaust port 5a is connected to an exhaust gas purification device not shown. For example, the exhaust gas purification device includes a catalyst. Usually, the catalyst is at room temperature when the engine is started. If the catalyst is heated to a temperature higher than a certain temperature, the exhaust gas is purified well.

[0033] The turbine housing 5 includes a connecting flow path 50. The connecting flow path 50 has an annular shape around the turbine impeller 2. The connecting flow path 50 is in fluid communication with the exhaust port 5a via the turbine impeller 2.

[0034] The turbine housing 5 includes a first scroll flow path (first flow path) 51. The first scroll flow path 51 is located radially outward of the connecting flow path 50. The first scroll flow path 51 has a substantially scroll shape. The first scroll flow path 51 communicates with the connecting flow path 50.

[0035] Figure 2 is along Figure 1 A schematic front view of the supercharger TC observed in the direction indicated by the arrow II in FIG. The turbine housing 5 has an exhaust gas inlet 5b. The inlet 5b is fluidly connected to the exhaust port of the engine, not shown. The inlet 5b receives the exhaust gas discharged from the engine. The inlet 5b includes a first inlet 51b and a second inlet 52b. For example, one exhaust pipe may be connected to both the first inlet 51b and the second inlet 52b. In addition, in other embodiments, a portion of the plurality of exhaust manifolds may also be connected to the first inlet 51b, and the remaining exhaust manifolds may also be connected to the second inlet 52b. The first vortex flow path 51 is connected to the first inlet 51b.

[0036] The turbine housing 5 includes a second scroll flow path (second flow path) 52. The second scroll flow path 52 will be described in detail later.

[0037] During normal operation of the engine, the exhaust gas is guided from the exhaust port of the engine to the first scroll flow path 51 through the first inlet 51b. Figure 1 , the exhaust gas is guided from the first vortex flow path 51 to the exhaust port 5a via the connecting flow path 50 and the turbine impeller 2. The exhaust gas rotates the turbine impeller 2 while passing through the turbine impeller 2. The rotational force of the turbine impeller 2 is transmitted to the compressor impeller 3 via the shaft 1. When the compressor impeller 3 rotates, as described above, air is sucked in from the intake port 6a, and is accelerated and pressurized by the compressor impeller 3. In the supercharger TC, the portion including the turbine impeller 2 and the turbine housing 5 functions as a turbine T.

[0038] Next, the second scroll flow path 52 of the turbine housing 5 will be described.

[0039] The turbine housing 5 includes a first space S1 that accommodates the turbine impeller 2. The turbine housing 5 also includes a second space S2 that is located downstream of the first space S1 in the flow of the exhaust gas. Specifically, the second space S2 is located between the first space S1 and the exhaust port 5a.

[0040] Figure 3 Yes means Figure 2 A partial stereogram of the portion surrounded by the dotted line in FIG. Figure 2 as well as Figure 3 In this embodiment, the second vortex flow path 52 has a substantially vortex shape. In other embodiments, as described later, the second flow path may have other shapes such as a circular ring shape or a straight line shape as long as the second inlet 52b is directly connected to the second space S2 instead of connecting the second inlet 52b to the first space S1. Figure 2 One end of the second scroll flow path 52 is connected to the second inlet 52b.

[0041] A valve V is provided at the second inlet 52b. The valve V opens and closes the second scroll flow path 52 based on a command from a control device (not shown). Position P1 indicates a closed position of the valve V closing the second scroll flow path 52. Position P2 indicates an open position of the valve V opening the second scroll flow path 52. The valve V is not limited to Figure 2 The structure shown may also be other structures. In addition, in order to open and close the first scroll flow path 51, a similar valve may be provided at the first inlet 51b.

[0042] Reference Figure 3 The other end of the second vortex flow path 52 is connected to the second space S2. The second vortex flow path 52 includes an outlet 52c that opens to the second space S2. Figure 2 In this embodiment, the outlet 52c (at Figure 2In the figure, the area with cross hatching has a circular ring shape when viewed in the axial direction and is continuous in the circumferential direction. In other embodiments, the outlet 52c may not be continuous in the circumferential direction, and may be provided in a part of the circumferential direction. In addition, for example, the second vortex flow path 52 may also include a plurality of outlets arranged in the circumferential direction.

[0043] Reference Figure 1 The second vortex flow path 52 is not connected to the first space S1. That is, the second vortex flow path 52 does not connect the second inlet 52b to the first space S1 but directly connects the second inlet 52b to the second space S2. The second vortex flow path 52 includes a portion that is formed radially outside the first space S1 through a wall and extends in an annular or cylindrical shape.

[0044] The outlet 52c of the second vortex flow path 52 is axially oriented toward the exhaust port 5a. According to such a structure, the flow direction of the exhaust gas flowing from the second vortex flow path 52 into the second space S2 is oriented toward the exhaust port 5a. Specifically, in the present embodiment, the inner peripheral surface 52d of the second vortex flow path 52 extends parallel to the axial direction within a range including the outlet 52c. In addition, in the present embodiment, the outer peripheral surface 52e of the second vortex flow path 52 extends parallel to the axial direction within a range including the outlet 52c. According to these structures, the flow direction of the exhaust gas flowing from the second vortex flow path 52 into the second space S2 is approximately parallel to the axial direction. In other embodiments, at least one of the inner peripheral surface 52d and the outer peripheral surface 52e may also be inclined relative to the axial direction within a range including the outlet 52c.

[0045] Reference Figure 3 , the volume of the second scroll flow path 52 is smaller than the volume of the first scroll flow path 51 .

[0046] Next, the function of the second scroll flow path 52 will be described.

[0047] Reference Figure 2 For example, when the engine is started, the valve V is opened. As a result, the second scroll flow path 52 is opened. A portion of the exhaust gas flows into the second scroll flow path 52 through the second inlet 52b. Figure 1 , the exhaust gas flows directly from the second vortex flow path 52 to the second space S2 without passing through the turbine impeller 2. Since the temperature of the exhaust gas bypassing the turbine impeller 2 does not drop, a higher temperature exhaust gas is supplied to the exhaust gas purification device compared to the case where the second vortex flow path 52 is not used. Therefore, when the engine is started, the catalyst can be quickly heated.

[0048] In addition, in the present embodiment, the second vortex flow path 52 is not connected to the first space S1, but is only connected to the second space S2. Therefore, a part of the exhaust gas can be efficiently guided to the second space S2. In addition, no valve for opening and closing the second vortex flow path 52 is provided in the second space S2. Therefore, the bypass flow flowing out of the second vortex flow path 52 and the main flow passing through the turbine impeller 2 are not blocked by the valve. Therefore, the exhaust gas can be smoothly guided.

[0049] In addition, in the present embodiment, the outlet 52c of the second vortex flow path 52 is axially oriented toward the exhaust port 5a. According to such a structure, the direction of the flow of the exhaust gas flowing from the second vortex flow path 52 into the second space S2 is oriented toward the exhaust port 5a. Therefore, the bypass flow smoothly merges with the mainstream. Therefore, the exhaust gas can be guided more smoothly.

[0050] As described above, the turbine T according to the present embodiment includes a turbine impeller 2 and a turbine housing 5 that accommodates the turbine impeller 2. The turbine housing 5 includes: an inlet 5b that is fluidly connected to the exhaust port of the engine; a first space S1 that accommodates the turbine impeller 2; a second space S2 that is located downstream of the first space S1 in the flow of exhaust gas from the engine; a first vortex flow path 51 that connects the inlet 5b to the first space S1; and a second vortex flow path 52 that connects the inlet 5b to the first space S1 and directly connects the inlet 5b to the second space S2. According to such a structure, the second vortex flow path 52 is not connected to the first space S1, but is only connected to the second space S2. Therefore, a part of the exhaust gas can be efficiently guided to the second space S2. In addition, a valve for opening and closing the second vortex flow path 52 is not provided in the second space S2. Therefore, the bypass flow and the main flow passing through the turbine impeller 2 are not blocked by the valve. Therefore, the exhaust gas can be smoothly guided.

[0051] In addition, in the above-mentioned embodiment, the turbine T is provided with a valve V for opening and closing the second scroll flow path 52 at a position upstream of the first space S1. According to such a structure, the valve V needs to be provided at least at the inlet 5b or at a position upstream of the inlet 5b. Therefore, when the valve V is closed during normal operation of the engine, the exhaust gas will not accumulate in the second scroll flow path 52. Therefore, during normal operation, the exhaust gas can be smoothly guided.

[0052] In addition, in the above-mentioned embodiment, the volume of the second vortex flow path 52 is smaller than the volume of the first vortex flow path 51. When the engine is started, the engine speed is low. Therefore, the amount of exhaust gas guided to the second vortex flow path 52 when the engine is started can be small. Therefore, according to the above-mentioned structure, the volume of the first vortex flow path 51 can be maximized.

[0053] In addition, in the above-mentioned embodiment, the second vortex flow path 52 has a vortex shape. Existing turbines sometimes have two vortex flow paths (so-called twin-vortex turbines) that are respectively connected to the turbine impeller fluid. In this case, the design of the existing turbine can be easily changed to the design of the present disclosure by only modifying the design of one vortex flow path.

[0054] In addition, in the above-mentioned embodiment, the turbine T has an exhaust port 5a located downstream of the second space S2 in the flow of the exhaust gas, and the second vortex flow path 52 is configured to be opposite to the exhaust port 5a in the axial direction. According to such a structure, the flow direction of the exhaust gas flowing from the second vortex flow path 52 into the second space S2 is toward the exhaust port 5a. Therefore, the bypass flow smoothly merges with the mainstream. Therefore, the exhaust gas can be guided more smoothly.

[0055] The embodiments of the present disclosure are described above with reference to the accompanying drawings, but the present disclosure is not limited to the embodiments. It is obvious that a person skilled in the art can think of various changes or modifications within the scope of the claims, and it is understood that they also belong to the technical scope of the present disclosure.

[0056] For example, in the above-described embodiment, the valve V is provided at the second inlet 52b. That is, the valve V is provided at the turbine T. However, in other embodiments, the valve V may be provided at a position outside the turbine T such as an exhaust manifold connecting the engine and the second inlet 52b.

[0057] Explanation of symbols

[0058] 2: Turbine impeller (impeller)

[0059] 5: Turbine housing (housing)

[0060] 5a: Exhaust port

[0061] 5b: Entrance

[0062] 51: First vortex flow path (first flow path)

[0063] 52: Second vortex flow path (second flow path)

[0064] S1: First Space

[0065] S2: Second Space

[0066] T: Turbine

[0067] V: Valve

Claims

1. A turbine, characterized in that: have: impeller; and A casing that accommodates the impeller, the casing comprising: an inlet that is fluidly connected to an exhaust port of an engine; a first space that accommodates the impeller; a second space that is located downstream of the first space in the flow of exhaust gas from the engine; a first flow path that connects the inlet and the first space; and a second flow path that does not connect the inlet and the first space but directly connects the inlet and the second space.

2. The turbine according to claim 1, characterized in that A valve for opening and closing the second flow path is provided at a position upstream of the first space.

3. The turbine according to claim 1 or 2, characterized in that The volume of the second flow path is smaller than the volume of the first flow path.

4. The turbine according to claim 1 or 2, characterized in that The second flow path has a spiral shape.

5. The turbine according to claim 3, characterized in that The second flow path has a spiral shape.

6. The turbine according to claim 1 or 2, characterized in that The turbine includes an exhaust port located downstream of the second space in the flow of the exhaust gas. The second flow path is configured to face the exhaust port in the axial direction of the impeller.

7. The turbine according to claim 3, characterized in that The turbine includes an exhaust port located downstream of the second space in the flow of the exhaust gas. The second flow path is configured to face the exhaust port in the axial direction of the impeller.

8. The turbine according to claim 4, characterized in that The turbine includes an exhaust port located downstream of the second space in the flow of the exhaust gas. The second flow path is configured to face the exhaust port in the axial direction of the impeller.

9. The turbine according to claim 5, characterized in that The turbine includes an exhaust port located downstream of the second space in the flow of the exhaust gas. The second flow path is configured to face the exhaust port in the axial direction of the impeller.

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