turbine

Abstract

This turbine T includes an impeller 2 and a housing 5 that houses the impeller 2. The housing 5 includes an inlet that is in fluid communication with an exhaust port of an engine, a first space S1 that houses the impeller 2, a second space S2 that is positioned downstream of the first space S1 along the direction in which exhaust gas flows from the engine, a first flow passage 51 that connects the inlet and the first space S1, and a second flow passage 52 that directly connects the inlet and the second space S2 without connecting the inlet and the first space S1.

Description

[Technical Field]

[0001] This application claims the benefit of priority from Japanese Patent Application No. 2022-142055, filed on September 7, 2022, the contents of which are incorporated herein by reference. [Background technology]

[0002] A turbine may be located in the exhaust path of an engine. The turbine's impeller is rotated by the exhaust gases from the engine, and the rotational force of the impeller is used by another device, such as a compressor to pressurize the engine's intake air.

[0003] A catalyst may also be provided in the exhaust flow path to purify the exhaust gas. When the engine is started, the catalyst is at room temperature. The catalyst will not function properly unless it is heated above a certain temperature. Therefore, the turbine may include a bypass flow path so that some of the exhaust gas bypasses the impeller. When the engine is started, a valve in the bypass flow path is opened so that some of the exhaust gas flows into the catalyst without passing through the impeller. With this configuration, the temperature of the exhaust gas bypassing the impeller does not decrease, allowing the catalyst to heat up quickly.

[0004] Patent Document 1 discloses a turbine including such a bypass passage. The turbine includes two scroll passages. Each of the two scroll passages is in fluid communication with a turbine wheel. One of the two scroll passages is connected to a bypass passage. The bypass passage connects the corresponding scroll passage to a space downstream of the turbine wheel. With this configuration, a portion of the exhaust gas flows into the space downstream of the turbine wheel without passing through the turbine wheel. A slide valve for opening and closing the bypass passage is provided in this space. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2017-141704 Summary of the Invention [Problem to be solved by the invention]

[0006] In the turbine of Patent Document 1, the valve in the bypass flow path may obstruct the flow of the main and bypass flows through the impeller, and therefore the exhaust gas may not be efficiently directed to the catalyst.

[0007] An object of the present disclosure is to provide a turbine that can smoothly guide exhaust gases. [Means for solving the problem]

[0008] In order to solve the above problems, a turbine according to one aspect of the present disclosure includes an impeller; and a housing that accommodates the impeller, the housing 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 a 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. The outlet of the second flow path is defined by an inner circumferential surface extending parallel to the axial direction of the impeller and continuous in the circumferential direction of the impeller, and an outer circumferential surface extending parallel to the axial direction and continuous in the circumferential direction of the impeller. .

[0009] The turbine may include a valve located upstream of the first space for opening and closing the second flow path.

[0010] The volume of the second flow path may be smaller than the volume of the first flow path.

[0011] The second flow path may have a spiral shape.

[0012] The turbine may include an exhaust port located downstream of the second space in the flow of the exhaust gas, the second flow path comprising: ,shaft The air intake port may be configured to face the exhaust port in a direction opposite to the exhaust port. [Effects of the Invention]

[0013] According to the present disclosure, exhaust gas can be smoothly guided. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view of a turbocharger including a turbine according to an embodiment. [Figure 2] FIG. 2 is a schematic front view of the supercharger as seen in the direction indicated by arrow II in FIG. [Figure 3] FIG. 3 is a partial perspective view showing the portion surrounded by the dashed line in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for ease of understanding and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation. Elements not directly related to the present disclosure are not shown.

[0016] 1 is a schematic cross-sectional view of a turbocharger TC including a turbine T according to an embodiment. In this embodiment, the turbine T is incorporated into the turbocharger TC. In other embodiments, the turbine T may be incorporated into a device other than the turbocharger TC, or may be a standalone device.

[0017] The turbocharger TC includes a shaft 1, a turbine impeller (impeller) 2, and a compressor impeller 3. As will be 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 may be simply referred to as the "axial direction," the "radial direction," and the "circumferential direction," respectively.

[0018] The turbocharger TC includes a bearing housing 4, a turbine housing (housing) 5, and a compressor housing 6. The turbine housing 5 is connected to a first end face of the bearing housing 4 in the axial direction, which is the left end face in FIG. 1. The compressor housing 6 is connected to a second end face of the bearing housing 4 in the axial direction, which is the right end face in FIG. 1.

[0019] The bearing housing 4 includes a bearing hole 4a. The bearing hole 4a extends axially within 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 be a full-floating bearing or another radial bearing such as a rolling bearing. The bearing 7 rotatably supports the shaft 1.

[0020] The turbine impeller 2 is provided at a first end of the shaft 1 in the axial direction, which is the left end in FIG. 1. The turbine impeller 2 rotates integrally with the shaft 1. The turbine impeller 2 is rotatably accommodated within a turbine housing 5.

[0021] The compressor impeller 3 is provided at a second end of the shaft 1 opposite the first end in the axial direction, that is, at the right end in FIG. 1. The compressor impeller 3 rotates integrally with the shaft 1. The compressor impeller 3 is rotatably housed within a compressor housing 6.

[0022] The compressor housing 6 includes an intake port 6a on the end face opposite the bearing housing 4 in the axial direction. The intake port 6a is connected to an air cleaner (not shown). The bearing housing 4 and the compressor housing 6 define a diffuser passage 60 therebetween. The diffuser passage 60 has an annular shape around the compressor impeller 3. The diffuser passage 60 is in fluid communication with the intake port 6a via the compressor impeller 3.

[0023] The compressor housing 6 includes a scroll passage 61. The scroll passage 61 is located radially outward of the diffuser passage 60. The scroll passage 61 is in fluid communication with the diffuser passage 60. The scroll passage 61 is also in fluid communication with an intake port of the engine (not shown). The scroll passage 61 has a generally spiral shape.

[0024] In the compressor housing 6 described above, when the compressor impeller 3 rotates, air is drawn into the compressor housing 6 through the intake port 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 passage 60 and the scroll passage 61. The compressed air flows out from an outlet (not shown) and is led to the intake port of the engine. In the turbocharger TC, the portion including the compressor impeller 3 and the compressor housing 6 functions as a centrifugal compressor C.

[0025] The turbine housing 5 includes an exhaust port 5a on the end face 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. Typically, the catalyst is at room temperature when the engine starts. When the catalyst is heated above a certain temperature, it effectively purifies the exhaust gas.

[0026] The turbine housing 5 includes a connecting passage 50. The connecting passage 50 has an annular shape around the turbine impeller 2. The connecting passage 50 is in fluid communication with the exhaust port 5a via the turbine impeller 2.

[0027] The turbine housing 5 includes a first scroll passage (first passage) 51. The first scroll passage 51 is located radially outward of the connecting passage 50. The first scroll passage 51 has a generally spiral shape. The first scroll passage 51 communicates with the connecting passage 50.

[0028] FIG. 2 is a schematic front view of the turbocharger TC as viewed in the direction indicated by arrow II in FIG. 1. The turbine housing 5 has an exhaust gas inlet 5b. The inlet 5b is fluidly connected to an exhaust port of the engine (not shown). The inlet 5b receives exhaust gas discharged from the engine. The inlet 5b includes a first inlet 51b and a second inlet 52b. For example, a single exhaust pipe may be connected to both the first inlet 51b and the second inlet 52b. In another embodiment, some of the multiple exhaust manifolds may be connected to the first inlet 51b, and the remaining exhaust manifolds may be connected to the second inlet 52b. The first scroll passage 51 is connected to the first inlet 51b.

[0029] The turbine housing 5 includes a second scroll passage (second passage) 52. The second scroll passage 52 will be described in detail later.

[0030] During normal operation of the engine, exhaust gas is guided from the exhaust port of the engine to the first scroll passage 51 via the first inlet 51b. Further, referring to FIG. 1 , the exhaust gas is guided from the first scroll passage 51 to the exhaust port 5a via the connecting passage 50 and the turbine impeller 2. The exhaust gas rotates the turbine impeller 2 while passing through it. 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, air is taken in from the intake port 6a and is accelerated and pressurized by the compressor impeller 3, as described above. In the turbocharger TC, a portion including the turbine impeller 2 and the turbine housing 5 functions as the turbine T.

[0031] Next, the second scroll passage 52 of the turbine housing 5 will be described.

[0032] The turbine housing 5 includes a first space S1 that houses 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 exhaust gas. Specifically, the second space S2 is located between the first space S1 and the exhaust port 5a.

[0033] Fig. 3 is a partial perspective view showing the portion surrounded by the dashed line in Fig. 2. Referring to Figs. 2 and 3, in this embodiment, the second scroll passage 52 has a generally spiral shape. In other embodiments, the second passage may have another shape, such as a circular or linear shape, as long as the second passage directly connects the second inlet 52b and the second space S2 without connecting the second inlet 52b and the first space S1, as will be described later. Referring to Fig. 2, one end of the second scroll passage 52 is connected to the second inlet 52b.

[0034] A valve V is provided at the second inlet 52b. The valve V opens and closes the second scroll passage 52 based on commands from a control device (not shown). Position P1 indicates a closed position where the valve V closes the second scroll passage 52. Position P2 indicates an open position where the valve V opens the second scroll passage 52. The valve V is not limited to that shown in FIG. 2 and may have other configurations. A similar valve may also be provided at the first inlet 51b to open and close the first scroll passage 51.

[0035] Referring to FIG. 3, the other end of the second scroll passage 52 is connected to the second space S2. The second scroll passage 52 includes an outlet 52c that opens into the second space S2. Referring to FIG. 2, in this embodiment, the outlet 52c (the cross-hatched area in FIG. 2) has an annular shape when viewed in the axial direction and is continuous in the circumferential direction. In other embodiments, the outlet 52c does not have to be continuous in the circumferential direction, and may be provided in part of the circumferential direction. Furthermore, for example, the second scroll passage 52 may include a plurality of outlets arranged along the circumferential direction.

[0036] 1, the second scroll passage 52 is not connected to the first space S1. That is, the second scroll passage 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 scroll passage 52 is formed radially outward from the first space S1 across a wall, and includes a portion extending in an annular or cylindrical shape.

[0037] The outlet 52c of the second scroll passage 52 faces the exhaust port 5a in the axial direction. With this configuration, the flow direction of the exhaust gas flowing from the second scroll passage 52 into the second space S2 is directed toward the exhaust port 5a. Specifically, in this embodiment, the inner circumferential surface 52d of the second scroll passage 52 extends parallel to the axial direction in a range including the outlet 52c. Also, in this embodiment, the outer circumferential surface 52e of the second scroll passage 52 extends parallel to the axial direction in a range including the outlet 52c. With these configurations, the flow direction of the exhaust gas flowing from the second scroll passage 52 into the second space S2 is approximately parallel to the axial direction. In other embodiments, at least one of the inner circumferential surface 52d and the outer circumferential surface 52e may be inclined with respect to the axial direction in a range including the outlet 52c.

[0038] Referring to FIG. 3, the volume of the second scroll passage 52 is smaller than the volume of the first scroll passage 51.

[0039] Next, the function of the second scroll passage 52 will be described.

[0040] Referring to FIG. 2, for example, when starting the engine, the valve V is opened. This opens the second scroll passage 52. A portion of the exhaust gas flows into the second scroll passage 52 through the second inlet 52b. Referring to FIG. 1, the exhaust gas flows directly from the second scroll passage 52 into the second space S2 without passing through the turbine impeller 2. Since the temperature of the exhaust gas that bypasses the turbine impeller 2 does not decrease, higher-temperature exhaust gas is supplied to the exhaust gas purification device compared to when the second scroll passage 52 is not used. Therefore, the catalyst can be heated quickly when starting the engine.

[0041] In this embodiment, the second scroll passage 52 is not connected to the first space S1, but is connected only to the second space S2. Therefore, a portion of the exhaust gas can be efficiently guided to the second space S2. Furthermore, no valve for opening and closing the second scroll passage 52 is provided in the second space S2. Therefore, the bypass flow flowing out from the second scroll passage 52 and the main flow passing through the turbine impeller 2 are not obstructed by a valve. Therefore, the exhaust gas can be smoothly guided.

[0042] In this embodiment, the outlet 52c of the second scroll passage 52 faces the exhaust port 5a in the axial direction. With this configuration, the flow direction of the exhaust gas flowing from the second scroll passage 52 into the second space S2 is directed toward the exhaust port 5a. Therefore, the bypass flow smoothly merges with the main flow. This allows the exhaust gas to be guided more smoothly.

[0043] As described above, the turbine T according to this embodiment includes the turbine impeller 2 and the turbine housing 5 that accommodates the turbine impeller 2. The turbine housing 5 includes an inlet 5b that is fluidly connected to an 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 scroll passage 51 that connects the inlet 5b to the first space S1, and a second scroll passage 52 that directly connects the inlet 5b to the second space S2 without connecting the inlet 5b to the first space S1. With this configuration, the second scroll passage 52 is not connected to the first space S1 but is connected only to the second space S2. Therefore, a portion of the exhaust gas can be efficiently guided to the second space S2. Furthermore, no valve for opening or closing the second scroll passage 52 is provided in the second space S2. Therefore, the bypass flow and the main flow passing through the turbine impeller 2 are not obstructed by the valve. Therefore, the exhaust gas can be smoothly guided.

[0044] Furthermore, in the above embodiment, the turbine T includes a valve V located upstream of the first space S1, which opens and closes the second scroll passage 52. With this configuration, the valve V needs to be located at least at the inlet 5b or upstream of the inlet 5b. Therefore, when the valve V is closed during normal operation of the engine, exhaust gas does not accumulate in the second scroll passage 52. Therefore, exhaust gas can be smoothly guided during normal operation.

[0045] In the above embodiment, the volume of the second scroll passage 52 is smaller than the volume of the first scroll passage 51. When the engine is started, the engine speed is low. Therefore, the amount of exhaust gas introduced into the second scroll passage 52 when the engine is started may be small. Therefore, with the above configuration, the volume of the first scroll passage 51 can be maximized.

[0046] In the above embodiment, the second scroll passage 52 has a spiral shape. Current turbines may have two scroll passages, each of which is in fluid communication with a turbine impeller (a so-called twin-scroll turbine). In this case, the design of the current turbine can be easily changed to that of the present disclosure by simply modifying the design of one of the scroll passages.

[0047] In the above embodiment, the turbine T includes an exhaust port 5a located downstream of the second space S2 in the flow of exhaust gas, and the second scroll passage 52 is configured to face the exhaust port 5a in the axial direction. With this configuration, the flow direction of the exhaust gas flowing from the second scroll passage 52 into the second space S2 is directed toward the exhaust port 5a. Therefore, the bypass flow smoothly merges with the main flow. This allows the exhaust gas to be guided more smoothly.

[0048] Although the embodiments of the present disclosure have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to such embodiments. It is clear that a person skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present disclosure.

[0049] For example, in the above 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 location external to the turbine T, such as an exhaust manifold that connects the engine and the second inlet 52b. [Explanation of symbols]

[0050] 2 Turbine impeller (impeller) 5 Turbine housing (housing) 5a Exhaust port 5b Entrance 51 First scroll passage (first passage) 52 Second scroll passage (second passage) S1 1st space S2 2nd space T Turbine V-valve

Claims

1. The impeller and A housing that accommodates the impeller, an inlet in fluid communication with an exhaust of the engine; a first space that accommodates the impeller; a second space located downstream of the first space in the flow of exhaust gas from the engine; a first flow path connecting the inlet and the first space; a second flow path that directly connects the inlet and the second space without connecting the inlet and the first space; a housing including: Equipped with an outlet of the second flow path is defined by an inner circumferential surface extending parallel to the axial direction of the impeller and continuous in the circumferential direction of the impeller, and an outer circumferential surface extending parallel to the axial direction and continuous in the circumferential direction; Turbine.

2. The turbine according to claim 1 , further comprising a valve located upstream of the first space for opening and closing the second flow path.

3. The turbine of claim 1 or 2, wherein the volume of the second flow path is smaller than the volume of the first flow path.

4. The turbine of claim 1 or 2, wherein the second flow path has a spiral shape.

5. The turbine of claim 3 , wherein the second flow path has a spiral shape.

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

7. the turbine includes an exhaust port located downstream of the second space in the flow of the exhaust gas; The turbine according to claim 3 , wherein the second flow passage is configured to face the exhaust port in the axial direction.

8. the turbine includes an exhaust port located downstream of the second space in the flow of the exhaust gas; The turbine according to claim 4 , wherein the second flow passage is configured to face the exhaust port in the axial direction.

9. the turbine includes an exhaust port located downstream of the second space in the flow of the exhaust gas; The turbine according to claim 5 , wherein the second flow passage is configured to face the exhaust port in the axial direction.

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