Double scroll turbine housing, double scroll turbine and turbocharger

Abstract

This twin-scroll turbine housing has formed therein a confluence passage in which a first branch passage branching from a first scroll passage and a second branch passage branching from a second scroll passage merge, and which communicates with an exhaust passage via an exhaust passage-side communication port. This twin-scroll turbine housing is provided with a scroll connection valve comprising a valve element that includes: a seat part comprising a seat surface that can be brought into and out of contact with the exhaust passage-side communication port; and a protruding part that protrudes out from the seat part toward the confluence passage to divide up the first branched passage and the second branched passage in the confluence passage. When a passage cross-section orthogonal to a direction parallel to a valve stem at a connected position of connection between the first branched passage and / or the second branched passage and the confluence passage has been subdivided into four predetermined regions, a fourth region has a smaller passage surface area than the other regions.

Description

[Technical field]

[0001] The present disclosure relates to a double scroll turbine housing, a double scroll turbine including the double scroll turbine housing, and a supercharger including the double scroll turbine. [Background technology]

[0002] Some double scroll turbine housings are formed with a first branch passage branching from a first scroll passage, a second branch passage branching from a second scroll passage, and a junction passage where the first branch passage and the second branch passage join and communicate with an exhaust passage through which exhaust gas that has passed through a turbine wheel flows (see Patent Document 1). The double scroll turbine housing described in Patent Document 1 discloses a valve that is capable of closing a communication port provided between the junction passage and the exhaust passage and has a valve body that is capable of separating the first branch passage and the second branch passage in the junction passage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2018-537615 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 describes that the flow rate characteristics when the valve is open can be made to approach ideal linear characteristics. However, with the double scroll turbine housing and valve shape described in Patent Document 1, there is a risk that the rate of increase in the open flow path area at the connection position between the first branch flow path and the junction flow path and between the second branch flow path and the junction flow path increases rapidly when the valve is open.

[0005] In view of the above circumstances, at least one embodiment of the present invention aims to provide a double scroll turbine housing, a double scroll turbine, and a turbocharger that can improve the flow characteristics when the scroll connection valve is open. [Means for solving the problem]

[0006] A double scroll turbine housing according to at least one embodiment of the present invention comprises: A double scroll turbine housing having two scroll passages formed therein, the two scroll passages include a first scroll passage and a second scroll passage formed in the same region as the first scroll passage in the axial direction of the turbine, The double scroll turbine housing comprises: a connection passage forming portion that forms a connection passage including a first branch passage branching from the first scroll passage, a second branch passage branching from the second scroll passage, and a junction passage where the first branch passage and the second branch passage join together and that communicates with an exhaust passage through which exhaust gas that has passed through the turbine flows, via an exhaust passage side communication port; a valve body having a seat portion including a seat surface that can be brought into contact with and separated from the exhaust flow path side communication port and that can open and close the exhaust flow path side communication port, and a protrusion that protrudes from the seat portion toward the junction flow path and that can separate each of the first branch flow path and the second branch flow path in the junction flow path, and a valve rod for rotating the valve body about a valve axis, A direction perpendicular to the seat surface of the valve body and away from the seat surface is defined as a height direction, A direction perpendicular to the height direction and a direction parallel to the valve axis is defined as a width direction, When a first flow passage cross section, which is a flow passage cross section perpendicular to a direction parallel to the valve axis at a connection position between at least one of the first branch flow passage and the second branch flow passage and the junction flow passage, is divided into four regions by a first reference line extending in the height direction and passing through a centroid of the first flow passage cross section and a second reference line extending in the width direction and passing through the centroid, Among the four regions, the side closer to the seat surface in the height direction than the centroid and farther from the valve axis in the width direction is defined as a first region, the side closer to the seat surface in the height direction than the centroid and farther from the valve axis in the width direction is defined as a second region, the side closer to the seat surface in the height direction than the centroid and farther from the valve axis in the width direction is defined as a third region, and the side closer to the seat surface in the height direction than the centroid and farther from the valve axis in the width direction is defined as a fourth region, The fourth region has a flow path area smaller than the first region, the second region, and the third region.

[0007] A double scroll turbine according to at least one embodiment of the present invention comprises: The double scroll turbine housing; a turbine wheel rotatably housed in the double scroll turbine housing.

[0008] A turbocharger according to at least one embodiment of the present invention includes: The double scroll turbine is driven by exhaust gas discharged from an engine; and a compressor that is coaxially connected to the double scroll turbine and that supplies compressed air to the engine as the turbine rotates. Effect of the Invention

[0009] According to at least one embodiment of the present invention, there are provided a double scroll turbine housing, a double scroll turbine, and a turbocharger capable of improving flow characteristics when a scroll connection valve is open. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a cross section perpendicular to an axis of a turbine wheel of a double scroll turbine according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing a cross section along an axis of a scroll connection valve of a double scroll turbine housing according to one embodiment. [Diagram 3] FIG. 1 is a schematic diagram showing a state in which a scroll connection valve of a double scroll turbine housing of one embodiment is fully closed, and shows a state in which the double scroll turbine housing is viewed from one side in the extension direction of the valve stem of the valve rod. [Figure 4] FIG. 1 is a schematic cross-sectional view of a double scroll turbine housing according to one embodiment, showing a flow passage cross section perpendicular to a direction parallel to a valve axis in a confluence flow passage, and a cross section perpendicular to a direction parallel to the valve axis of a valve body inserted into the confluence flow passage. [Diagram 5] 1 is a schematic diagram of a passage cross section perpendicular to a direction parallel to a valve axis at a connection position between a first branch passage and a second branch passage and a junction passage of a double scroll turbine housing according to one embodiment. FIG. [Figure 6] 1 is a schematic diagram of a passage cross section perpendicular to a direction parallel to a valve axis at a connection position between a first branch passage and a second branch passage and a junction passage of a double scroll turbine housing according to one embodiment. FIG. [Figure 7] FIG. 2 is an explanatory diagram for explaining flow rate characteristics of an SCV flow when a scroll connection valve of a double scroll turbine housing according to an embodiment is opened. [Figure 8] FIG. 10 is an explanatory diagram for explaining flow rate characteristics of a bypass flow when a scroll connection valve of a double scroll turbine housing according to an embodiment is opened. [Figure 9] FIG. 1 is a schematic cross-sectional view of a double scroll turbine housing according to one embodiment, showing a flow passage cross section perpendicular to a direction parallel to a valve axis in a confluence flow passage, and a cross section perpendicular to a direction parallel to the valve axis of a valve body inserted into the confluence flow passage. [Figure 10]FIG. 1 is a schematic cross-sectional view of a double scroll turbine housing according to one embodiment, showing a flow passage cross section perpendicular to a direction parallel to a valve axis in a confluence flow passage, and a cross section perpendicular to a direction parallel to the valve axis of a valve body inserted into the confluence flow passage. [Figure 11] FIG. 1 is a schematic configuration diagram illustrating a configuration of a turbocharger according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as the embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0012] (Double scroll turbine, double scroll turbine housing) Fig. 1 is a schematic cross-sectional view showing a cross section perpendicular to an axis LA of a turbine wheel 3 of a double scroll turbine 1 according to one embodiment. Fig. 2 is a schematic cross-sectional view showing a cross section along an axis LB of a scroll connection valve 4 of a double scroll turbine housing 2 according to one embodiment. Hereinafter, the direction in which the axis LA of the turbine wheel 3 extends when the turbine wheel 3 is housed in the double scroll turbine housing 2 is defined as the axial direction of the turbine wheel 3 (turbine 1).

[0013] As shown in Fig. 1, a double scroll turbine (hereinafter referred to as turbine) 1 includes a double scroll turbine housing (hereinafter referred to as housing) 2 in which two scroll passages 21, 22 are formed, and a turbine wheel 3 rotatably accommodated in the housing 2. The two scroll passages 21, 22 include a first scroll passage 21 and a second scroll passage 22 formed in the same region in the axial direction of the turbine 1 as the first scroll passage 21. Note that "formed in the same region in the axial direction of the turbine 1" means that the scroll shapes of the first scroll passage 21 and the second scroll passage 22 are displayed together in a cross section perpendicular to the axis LA of the turbine wheel 3 as shown in Fig. 1.

[0014] As shown in FIG. 1, the housing 2 includes a first scroll passage forming section 210 that forms the first scroll passage 21, and a second scroll passage forming section 220 that forms the second scroll passage 22. Each of the first scroll passage 21 and the second scroll passage 22 is a passage for introducing exhaust gas into a nozzle passage 23 of the turbine 1. The nozzle passage 23 is provided downstream of the first scroll passage 21 and the second scroll passage 22 in an exhaust gas passage through which exhaust gas discharged from the engine flows. The nozzle passage 23 is formed of an annular space formed inside the housing 2 and on the outer periphery side of the turbine wheel 3 (outside in the radial direction of the turbine wheel 3). Each of the first scroll passage 21 and the second scroll passage 22 is formed of a spiral passage provided on the outer periphery side of the nozzle passage 23.

[0015] 1, the housing 2 is configured so that a first range CR1 of the nozzle passage 23 into which the exhaust gas flowing through the first scroll passage 21 is introduced and a second range CR2 of the nozzle passage 23 into which the exhaust gas flowing through the second scroll passage 22 is introduced do not overlap in the circumferential direction about the axis line LA of the turbine wheel 3. In the illustrated embodiment, the second scroll passage 22 is provided on the outer circumferential side (outside in the radial direction of the turbine wheel 3) of the first scroll passage 21 in a cross section perpendicular to the axis line LA of the turbine wheel 3, and the first scroll passage 21 and the second scroll passage 22 at least partially overlap in the circumferential direction of the turbine wheel 3. Note that the first scroll passage 21 and the second scroll passage 22 may be configured so as not to overlap in the circumferential direction of the turbine wheel 3.

[0016] Exhaust gas discharged from the engine and introduced into the turbine 1 flows through the first scroll passage 21 and the second scroll passage 22, and is guided to the turbine wheel 3 from the outer periphery of the turbine wheel 3 through the nozzle passage 23. The exhaust gas guided to the turbine wheel 3 is discharged to the outside of the turbine 1 through the exhaust passage 28 (see FIG. 2).

[0017] (Connection flow path forming part) 1 and 2, the housing 2 is formed with a first branch passage 24 branching off from the first scroll passage 21 and a second branch passage 25 branching off from the second scroll passage 22. The first branch passage 24 communicates with the first scroll passage 21 so that exhaust gas can flow therebetween, as a one-end connection port 241 formed at one end of the first branch passage 24 is connected to the first scroll passage 21. The second branch passage 25 communicates with the second scroll passage 22 so that exhaust gas can flow therebetween, as a one-end connection port 251 formed at one end of the second branch passage 25 is connected to the second scroll passage 22.

[0018] 2, the housing 2 further includes a connection passage forming portion 270 that forms a connection passage 27 including the first branch passage 24, the second branch passage 25, and the junction passage 26, and an exhaust passage forming portion 280 that forms an exhaust passage 28 through which exhaust gas that has passed through the turbine 1 (specifically, the turbine wheel 3) flows. The first branch passage 24 and the second branch passage 25 join together in the junction passage 26. The junction passage 26 is connected, via an exhaust passage side communication port 29, to the exhaust passage 28 through which exhaust gas that has passed through the turbine 1 (specifically, the turbine wheel 3) flows.

[0019] The first branch flow path 24 is connected to the junction flow path 26 through an other end connection port 242 formed at the other end of the first branch flow path 24, and the second branch flow path 25, and the exhaust flow path 28 so that exhaust gas can flow therethrough. The second branch flow path 25 is connected to the junction flow path 26 through an other end connection port 252 formed at the other end of the second branch flow path 25, and the exhaust flow path 28 so that exhaust gas can flow therethrough.

[0020] 3 is a schematic diagram showing a state in which the scroll connection valve 4 of the double scroll turbine housing 2 according to one embodiment is fully closed, and showing a state in which the double scroll turbine housing 2 is viewed from one side in the valve axis LC (the extension direction of the valve axis of the valve rod 6). As shown in Figs. 2 and 3, the scroll connection valve (hereinafter referred to as valve) 4 includes a valve body 5 having a seat portion 51 and a protruding portion 53 protruding from the seat portion 51 toward the junction flow passage 26, and a valve rod 6 for rotating the valve body 5 around the valve axis LC. The valve axis LC is the axis of the valve rod 6.

[0021] The seat portion 51 includes a seat surface 52 that is movable toward and away from the exhaust passage side communication port 29. In the illustrated embodiment, the seat portion 51 has an annular plate shape that includes the seat surface 52 extending along a direction perpendicular to the axis LB of the valve body 5 (scroll connection valve 4).

[0022] The protruding portion 53 is configured to be able to separate the first branch flow path 24 and the second branch flow path 25 in the junction flow path 26. In the illustrated embodiment, the protruding portion 53 has a convex shape that protrudes in a direction away from the seat surface 52 in the extension direction of the axis LB of the valve body 5.

[0023] The valve 4 is configured to be able to adjust the aperture of the valve element 5. Specifically, the valve 4 further includes a rotation drive device including an actuator (not shown) for rotating the valve rod 6 about a valve axis LC. The valve 4 is able to adjust the aperture of the valve element 5 to an aperture corresponding to an angular position in the circumferential direction of the valve axis LC by rotating the valve rod 6 and the valve element 5 connected to the valve rod 6 about the valve axis LC. The valve 4 is configured to be able to adjust the aperture of the valve element 5 to a fully open, a fully closed, or at least one intermediate aperture between the fully open and fully closed positions.

[0024] In the extremely low rotation range and the low rotation range of the engine, the entire amount of exhaust gas discharged from the engine can be guided to the nozzle passage 23 by either the first scroll passage 21 or the second scroll passage 22, so that the opening degree of the valve body 5 is fully closed. As shown in Figs. 2 and 3, when the opening degree of the valve body 5 is fully closed, the protruding portion 53 of the valve body 5 blocks the junction passage 26, and the gap between the protruding portion 53 and the junction passage 26 becomes narrow, so that the SCV flow, that is, the flow from either the first branch passage 24 or the second branch passage 25 to the other, is suppressed. Also, as shown in Fig. 2, when the opening degree of the valve body 5 is fully closed, the seat surface 52 of the valve body 5 abuts against the seat abutment surface 291 of the connection passage forming portion 270. The seat abutment surface 291 is a surface that is connected to the exhaust passage-side communication port 29, extends along a direction perpendicular to the axis LD of the exhaust passage-side communication port 29, and faces the exhaust passage 28. The seat surface 52 and the seat abutment surface 291 contact each other to block the space between the junction passage 26 and the exhaust passage 28, thereby suppressing a bypass flow (WG flow) in which exhaust gas detouring the turbine wheel 3 and being introduced from the junction passage 26 to the exhaust passage 28.

[0025] In the medium rotation range of the engine, the flow rate of exhaust gas discharged from the engine is higher than in the low rotation range, and it becomes difficult to guide the entire amount of exhaust gas discharged from the engine to the nozzle passage 23 using only either the first scroll passage 21 or the second scroll passage 22. For this reason, the opening degree of the valve body 5 is set to a first intermediate opening degree that is larger than the fully closed state, thereby generating the above-mentioned SCV flow, and sending the excess exhaust gas from one of the first scroll passage 21 or the second scroll passage 22 to the other.

[0026] In the high rotation range of the engine, even if the SCV flow is increased, it becomes difficult for the first scroll passage 21 and the second scroll passage 22 to guide all of the exhaust gas discharged from the engine to the nozzle passage 23. For this reason, the opening of the valve element 5 is set to a second intermediate opening degree larger than the first intermediate opening degree or fully opened to increase the above-mentioned bypass flow, and the excess exhaust gas is sent from the first scroll passage 21 and the second scroll passage 22 to the exhaust passage 28. Note that a small amount of bypass flow may be generated when the opening of the valve element 5 is set to the first intermediate opening degree.

[0027] 4 is a schematic cross-sectional view of a double scroll turbine housing according to an embodiment, showing a flow passage cross section perpendicular to the direction parallel to the valve axis in the merging flow passage and a cross section perpendicular to the direction parallel to the valve axis of a valve disc inserted into the merging flow passage. In the illustrated embodiment, the above-mentioned protrusion 53 includes a valve stem proximate end face 54 located on the valve stem LC side of the axis LB of the valve disc 5, a valve stem distal end face 55 located on the side farther from the valve stem LC than the valve stem proximate end face 54 and the axis LB of the valve disc 5, and a bottom surface 56 connecting a tip 541 of the valve stem proximate end face 54 and a tip 551 of the valve stem distal end face 55 in a cross section perpendicular to the direction parallel to the valve axis LC as shown in FIG. Each of the valve stem proximate end face 54 and the valve stem distal end face 55 extends along the extension direction of the axis LB of the valve disc 5. The tip 541 and the tip 551 are ends on the side away from the seat surface 52. The bottom surface 56 extends along a direction intersecting the axis LB of the valve body 5 (in the illustrated example, a direction perpendicular to the axis LB).

[0028] 4, the connection flow passage forming portion 270 includes a stem adjacent side wall surface 271 located on the stem LC side of the axis LD of the exhaust flow passage side communication port 29, a stem distant side wall surface 272 located on the side farther from the stem LC than the stem adjacent side wall surface 271 and the axis LD, and a bottom wall surface 275 connecting a tip 273 of the stem adjacent side wall surface 271 and a tip 274 of the stem distant side wall surface 272. Each of the stem adjacent side wall surface 271, the stem distant side wall surface 272, and the bottom wall surface 275 is a wall surface that defines a part of the junction flow passage 26 and faces the junction flow passage 26.

[0029] The stem-proximate wall surface 271 and the stem-distant wall surface 272 each extend along the extension direction of the axis LD of the exhaust passage-side communication port 29. The tips 273 and 274 are ends opposite to the ends forming the exhaust passage-side communication port 29. The bottom wall surface 275 extends along a direction intersecting the axis LD of the exhaust passage-side communication port 29 (in the illustrated example, a direction perpendicular to the axis LD). When the valve 4 is in a fully closed state, the stem-proximate end surface 54 faces the stem-proximate wall surface 271, the stem-distant end surface 55 faces the stem-distant wall surface 272, and the bottom surface 56 faces the bottom wall surface 275.

[0030] 4, each of the stem-proximal end face 54 and the stem-distal end face 55 has a curved shape in which the distance from the axis LB decreases as the end face moves away from the seat surface 52 in the direction in which the axis LB extends. Each of the stem-proximal wall surface 271 and the stem-distal wall surface 272 has a curved shape in which the distance from the axis LD decreases as the end face moves away from the exhaust passage-side communication port 29 in the direction in which the axis LD extends.

[0031] 5 and 6 are schematic diagrams of a passage cross section perpendicular to a direction parallel to the valve axis LC at a connection position (other-end connection port 242, 252) between the first branch passage 24 and the second branch passage 25 and the junction passage 26 of the double scroll turbine housing 2 according to one embodiment. As shown in Fig. 3, a direction perpendicular to the seat surface 52 of the valve body 5 and away from the seat surface 52 is defined as a height direction HD, and a direction perpendicular to the height direction HD and a direction parallel to the valve axis LC of the valve rod 6 is defined as a width direction WD. 5 and 6, a flow passage cross section (first flow passage cross section) 7 perpendicular to a direction parallel to the valve axis LC at a connection position (other-end connection ports 242, 252) between at least one of the first branch flow passage 24 and the second branch flow passage 25 and the junction flow passage 26 is divided into four regions 71, 72, 73, and 74 by a first reference line RL1 that extends in the height direction HD in the flow passage cross section 7 and passes through the centroid RP of the flow passage cross section 7 and a second reference line RL2 that extends in the width direction WD in the flow passage cross section 7 and passes through the centroid RP. The second reference line RL2 is perpendicular to the first reference line RL1 at the centroid RP of the flow passage cross section 7.

[0032] As shown in Figures 5 and 6, of the four regions 71, 72, 73, 74 obtained by dividing the flow passage cross section 7, the side of the seat surface 52 in the height direction HD from the centroid RP (upper side in Figures 5 and 6) and the side away from the valve axis LC in the width direction WD from the centroid RP (left side in Figures 5 and 6) is defined as a first region 71, the side of the seat surface 52 in the height direction HD from the centroid RP and the side of the valve axis LC in the width direction WD from the centroid RP (right side in Figures 5 and 6) is defined as a second region 72, the side of the seat surface 52 in the height direction HD from the centroid RP (lower side in Figures 5 and 6) and the side of the valve axis LC in the width direction WD from the centroid RP is defined as a third region 73, and the side of the seat surface 52 in the height direction HD from the centroid RP and the side of the valve axis LC in the width direction WD from the centroid RP is defined as a fourth region 74.

[0033] The definitions of the height direction HD, the width direction WD, the centroid RP, and the first region 71 to the fourth region 74 are based on the case where the valve body 5 is fully closed. When defining these, the seat abutment surface 291 may be used instead of the seat surface 52, and the axis LD may be used instead of the axis LB.

[0034] As shown in Fig. 2, a housing (double scroll turbine housing) 2 according to some embodiments includes a connection passage forming portion 270 that forms a connection passage 27 including the first branch passage 24, the second branch passage 25, and the junction passage 26 described above, and a scroll connection valve 4 including a valve body 5 having a seat portion 51 and a protruding portion 53 described above, and a valve rod 6. As shown in Fig. 5 and Fig. 6, in the passage cross section 7 perpendicular to the direction parallel to the valve axis LC at the connection position (other end side connection port 242, 252) between at least one of the first branch passage 24 and the second branch passage 25 and the junction passage 26, the passage area of ​​the fourth region 74 is smaller than the passage area of ​​each of the first region 71, the second region 72, and the third region 73.

[0035] 5, the flow passage cross section 7 has a length in the width direction WD that monotonically increases toward the valve axis LC side as it approaches the seat surface 52 side in the height direction HD. Specifically, the second region 72, the third region 73, and the fourth region 74 each include an increased width region 72A, 73A, and 74A whose length in the width direction WD increases toward the valve axis LC side as it approaches the seat surface 52 side in the height direction HD. The first region 71 and the third region 73 each include a constant width region 71B, 73B whose length in the width direction WD is constant. The constant width region 73B is formed closer to the seat surface 52 side in the height direction HD than the increased width region 73A.

[0036] 5, the connection flow-path forming portion 270 includes, in a cross section perpendicular to the direction parallel to the valve axis LC at the above-mentioned connection positions (other-end connection ports 242, 252), a valve axis proximate oblique side portion 75 inclined toward a side away from the valve axis LC in the width direction WD as it approaches a side away from the seat surface 52 in the height direction HD, a valve axis distal side portion 76 located on a side farther from the valve axis LC than the valve axis proximate oblique side portion 75 and extending along the height direction HD, and a bottom portion 77 connecting a base end which is the end of the valve axis proximate oblique side portion 75 on the seat surface 52 side and a base end which is the end of the valve axis distal side portion 76 on the seat surface 52 side. The tip of the valve axis proximate oblique side portion 75 is continuous with the tip of the valve axis distal side portion 76.

[0037] In the embodiment shown in FIG. 6, the length of the flow passage cross section 7 in the width direction WD increases monotonically toward the valve axis LC side as it approaches the seat surface 52 side in the height direction HD, and then becomes constant. Specifically, the third region 73 and the fourth region 74 each include an expanded width region 73A, 74A in which the length of the width direction WD increases toward the valve axis LC side as it approaches the seat surface 52 side in the height direction HD. The first region 71, the second region 72, the third region 73, and the fourth region 74 each include a constant width region 71B, 72B, 73B, 74B in which the length of the width direction WD is constant. The constant width region 73B is formed closer to the seat surface 52 side in the height direction HD than the expanded width region 73A. The constant width region 74B is formed closer to the seat surface 52 side in the height direction HD than the expanded width region 74A. In at least a part of the height direction HD in which the constant width region 71B of the first region 71 is formed, the constant width region 72B of the second region 72 is formed. In at least a part of the height direction HD where the constant width region 73B of the third region 73 is formed, a constant width region 74B of the fourth region 74 is formed.

[0038] 6, the connection flow passage forming portion 270 includes, in a cross section perpendicular to the direction parallel to the valve axis LC at the above-mentioned connection position (the other end side connection port 242, 252), a valve axis nearby side oblique side portion 75 inclined toward the side away from the valve axis LC in the width direction WD as it approaches the side away from the seat surface 52 in the height direction HD, a valve axis far side edge portion 76 located on the side farther from the valve axis LC than the valve axis nearby side oblique side portion 75 and extending along the height direction HD, a valve axis nearby side straight side portion 78 extending along the height direction HD from a base end which is the end of the valve axis nearby side oblique side portion 75 on the seat surface 52 side, and a bottom side portion 77 connecting a base end which is the end of the valve axis nearby side straight side portion 78 on the seat surface 52 side and a base end which is the end of the valve axis far side side portion 76 on the seat surface 52 side. The tip of the valve axis nearby side oblique side portion 75 is continuous with the tip of the valve axis far side side portion 76.

[0039] 4 and 9 and 10 described later, the protrusion 53 when the valve element 5 is in a fully closed state is indicated by a solid line, the protrusion 53 when the valve element 5 is in an intermediate opening state is indicated by a dashed line, the protrusion 53 when the valve element 5 is in a fully open state is indicated by a dashed two-dot line, and the flow passage cross section 7 located on the nearer side or further back side of the drawing plane than the flow passage cross section (second flow passage cross section) 8 perpendicular to the direction parallel to the valve axis LC of the junction flow passage 26 is indicated by a dotted line. Note that the flow passage cross section 8 may be a cross section including the axis LD.

[0040] In the embodiment shown in FIG. 4, when viewed from one side in the extending direction of the stem LC, the flow passage cross section (first flow passage cross section) 7 is closed on the stem LC side and on the side remote from the stem LC in the width direction WD compared to the flow passage cross section (second flow passage cross section) 8. When viewed from one side in the extending direction of the stem LC, the flow passage cross section (first flow passage cross section) 7 is closed on the seat surface 52 side and on the side remote from the seat surface 52 in the height direction HD compared to the flow passage cross section (second flow passage cross section) 8. As shown in FIG. 4, the stem-proximate oblique side portion 75 is provided on the side remote from the stem LC in the width direction WD than the stem-proximate end face 54 and the stem-proximate side wall face 271 in the fully closed state. The stem-distant side portion 76 is provided on the stem LC side in the width direction WD than the stem-distant end face 55 and the stem-distant side wall face 272 in the fully closed state. Further, the valve stem proximate oblique side portion 75 and the valve stem distal side portion 76 are provided closer to the seat surface 52 in the height direction HD than the bottom surface 56 and the bottom wall surface 275 in the fully closed state.

[0041] FIG. 7 is an explanatory diagram for explaining the flow characteristic of the SCV flow when the scroll connection valve of the double scroll turbine housing according to the embodiment is opened. FIG. 8 is an explanatory diagram for explaining the flow characteristic of the bypass flow when the scroll connection valve of the double scroll turbine housing according to the embodiment is opened. Base in FIGS. 7 and 8 is a curve showing the flow characteristic (relationship between the opening degree of the valve 4 and the SCV flow or the bypass flow) in a rectangular flow passage cross section (first flow passage cross section) 7 having a constant width region in which the length in the width direction WD is constant as shown in FIG. 3. Case 1 in FIGS. 7 and 8 is a curve showing the flow characteristic in the flow passage cross section 7 as shown in FIG. 5 or FIG. 6. In Base, when the valve 4 is opened (i.e., when the position of the valve body 5 is changed from the fully closed position to a predetermined open position), the increase rate of the opening flow passage area in the flow passage cross section 7 (the area of ​​the region not blocked by the protrusion 53 in the flow passage cross section 7) increases rapidly, and the flow rate of the exhaust gas passing through the junction flow passage 26 (SCV flow) increases rapidly. In contrast, compared to Base, Case 1 can suppress a sudden increase in the opening flow passage area OA1 (area of ​​the region not blocked by the protrusion 53 in the flow passage cross section 7, see FIG. 4) when the valve 4 is opened. This makes the SCV flow relative to the opening of the valve 4 approach an ideal linear characteristic, improving the controllability of the SCV flow.

[0042] According to the above configuration, by making the flow path area of ​​the fourth region 74 smaller than the flow path areas of the other regions (the first region 71, the second region 72, and the third region 73), it is possible to suppress a sudden increase in the rate of increase of the opening flow path area OA1 in the flow path cross section 7 when the valve 4 is opened, and to suppress a sudden increase in the flow rate of the exhaust gas passing through the junction flow path 26. As a result, the SCV flow with respect to the opening degree of the valve 4 approaches a linear characteristic, thereby improving the controllability of the SCV flow. Therefore, according to the above configuration, it is possible to improve the flow rate characteristics when the valve 4 is open.

[0043] In some embodiments, as shown in Figures 5 and 6, each of the third region 73 and the fourth region 74 described above includes at least an expanded region 73A, 74A whose length in the width direction WD increases toward the valve axis LC as it approaches the seat surface 52 in the height direction HD.

[0044] According to the above configuration, since the third region 73 and the fourth region 74 each include the widened regions 73A and 74A, a rapid increase in the opening flow passage area OA1 in the flow passage cross section 7 when the valve 4 is open can be suppressed, and the SCV flow can be made closer to a linear characteristic with respect to the opening degree of the valve 4. This improves the controllability of the SCV flow when the valve 4 is open.

[0045] 5, the third region 73 and the fourth region 74 each include a widening region 73A, 74A. The second region 72 includes a widening region 72A whose length in the width direction WD increases toward the valve shaft LC as it approaches the seat surface 52 in the height direction HD.

[0046] According to the above configuration, since the second region 72 includes the widened region 72A, it is possible to suppress a sudden increase in the opening flow passage area OA1 in the flow passage cross section 7 when the valve 4 is open, and it is possible to make the SCV flow closer to a linear characteristic with respect to the opening degree of the valve 4. This improves the controllability of the SCV flow when the valve 4 is open.

[0047] 6, the third region 73 and the fourth region 74 each include a widened region 73A, 74A. The first region 71 and the second region 72 each include a constant width region 71B, 72B whose length in the width direction WD is constant. The constant width region 72B of the second region 72 is formed in at least a part of the height direction HD where the constant width region 71B of the first region 71 is formed.

[0048] According to the above configuration, since the first region 71 and the second region 72 include the constant width regions 71B, 72B, it is possible to suppress a sudden increase in the rate of increase in the opening flow path area OA1 in the flow path cross section 7 when the valve 4 is open, and it is possible to make the SCV flow closer to a linear characteristic with respect to the opening degree of the valve 4. This improves the controllability of the SCV flow when the valve 4 is open.

[0049] Furthermore, with the above configuration, the flow path width of the flow path cross section 7 is large in the range in the height direction HD where both the constant width region 71B and the constant width region 72B are formed. This makes it possible to increase the SCV flow when the valve 4 is in the large opening position. By changing the range in the height direction HD where both the constant width region 71B and the constant width region 72B are formed, it is possible to adjust the flow rate of the SCV flow relative to the opening of the valve 4.

[0050] In some embodiments, as shown in FIG. 4, the above-mentioned flow path cross section (first flow path cross section) 7 is blocked on the side away from the valve axis LC in the width direction WD and on the side away from the seat surface 52 in the height direction HD, compared to the flow path cross section 8 perpendicular to the direction parallel to the valve axis LC of the merging flow path 26.

[0051] According to the above configuration, the flow path cross section 7 at the connection positions 242, 252 is closed on the side away from the valve axis LC in the width direction WD and on the side away from the seat surface 52 in the height direction HD, compared to the flow path cross section 8 perpendicular to the direction parallel to the valve axis LC of the junction flow path 26. In this case, it becomes easy to separate the first branch flow path 24 and the second branch flow path 25 by the valve 4, and therefore it is possible to improve the sealing performance when the valve 4 is fully closed.

[0052] 9 is a schematic cross-sectional view of a double scroll turbine housing 2 according to one embodiment, showing a flow passage cross section 8 perpendicular to a direction parallel to the valve axis LC in the junction flow passage 26, and a cross section perpendicular to a direction parallel to the valve axis LC of the valve body 5 inserted into the junction flow passage 26. In some embodiments, the above-mentioned protrusion 53 includes, in a cross section perpendicular to a direction parallel to the valve axis LC, the above-mentioned valve axis proximate end face 54 located on the valve axis LC side, the above-mentioned valve axis distal end face 55 located on a side farther from the valve axis LC than the valve axis proximate end face 54, and the above-mentioned bottom face 56 connecting a tip 541 of the valve axis proximate end face 54 and a tip 551 of the valve axis distal end face 55, as shown in FIG.

[0053] The bottom surface 56 (56A) is inclined such that the distance from the seat surface 52 becomes shorter from the tip 551 of the stem-rear end surface 55 toward the stem LC side. As shown in FIG. 9, the tip 541 of the stem-proximal end surface 54 is located closer to the seat surface 52 than the tip 551 of the stem-rear end surface 55 in the height direction. The gap between the bottom surface 56A and the bottom wall surface 275 is larger on the stem LC side in the width direction WD than on the side away from the stem LC in the width direction WD. Therefore, the housing 2 according to the embodiment shown in FIG. 9 has improved exhaust gas flowability in the junction flow passage 26 compared to the housing 2 according to the embodiment shown in FIG. 4.

[0054] 7 and 8 is a curve showing the flow rate characteristics in the housing 2 as shown in Fig. 9. In Case 2, the flow rate of the SCV flow relative to the opening degree of the valve 4 can be increased compared to Case 1.

[0055] According to the above configuration, by inclining the bottom surface 56A of the protrusion 53 so that the distance from the seat surface 52 decreases from the tip 551 of the stem-rear end surface 55 toward the stem LC side, it is possible to increase the flow rate in the SCV flow direction (communication direction) when the valve 4 is open while suppressing an increase in the opening flow path area OA1 in the SCV flow direction (communication direction) and the opening flow path area OA2 in the bypass flow direction (area of ​​the region not blocked by the protrusion 53 in the exhaust flow path side communication port 29, see FIG. 9 ) when the valve 4 is open. By changing the inclined shape of the bottom surface 56A, it is possible to adjust the flow rate of the SCV flow relative to the opening of the valve 4.

[0056] 10 is a schematic cross-sectional view of a double scroll turbine housing 2 according to an embodiment, showing a flow passage cross section 8 perpendicular to a direction parallel to the valve axis LC in the junction flow passage 26, and a cross section perpendicular to a direction parallel to the valve axis LC of the valve body 5 inserted into the junction flow passage 26. In some embodiments, the above-mentioned protruding portion 53 includes, in a cross section perpendicular to a direction parallel to the valve axis LC, the above-mentioned valve axis proximate end face 54 located on the valve axis LC side, the above-mentioned valve axis distal end face 55 located on a side farther from the valve axis LC than the valve axis proximate end face 54, and the above-mentioned bottom surface 56 connecting the tip 541 of the valve axis proximate end face 54 and the tip 551 of the valve axis distal end face 55, as shown in FIG. 10. The valve axis proximate end face 54 has an inclined surface 54A having a larger inclination angle (an angle formed by a tangent to the end face and the above-mentioned end face) than the valve axis distal end face 55 facing the valve axis LC across the axis LB of the protruding portion 53 (valve body 5). The valve stem adjacent end surface 54 includes an inclined surface 54A and a surface 54B extending in the height direction from a base end 542 (the end on the seat surface 52 side) of the inclined surface 54A.

[0057] The inclined surface 54A is inclined from the base end 542 toward the side away from the valve axis LC in the width direction WD as it moves away from the seat surface 52 in the height direction HD. The tip 541 of the inclined surface 54A is located on the side away from the valve axis LC in the width direction WD than the base end 542. The valve axis proximate end face 54 including the inclined surface 54A has a larger gap between it and the wall surface forming the junction flow passage 26 than the valve axis distal end face 55. That is, the gap between the inclined surface 54A and the valve axis proximate side wall surface 271 is larger than the gap between the valve axis distal end face 55 and the valve axis distal side wall surface 272, which face the inclined surface 54A across the axis LB. Therefore, the housing 2 according to the embodiment shown in FIG. 10 has improved exhaust gas flowability in the junction flow passage 26 compared to the housing 2 according to the embodiment shown in FIG. 4.

[0058] 7 and 8 is a curve showing the flow rate characteristics in the housing 2 as shown in Fig. 10. In Case 3, the flow rate of the SCV flow relative to the opening degree of the valve 4 can be increased compared to Case 1.

[0059] According to the above configuration, the end face 54 near the valve shaft of the protruding portion 53 has the inclined surface 54A, which makes it possible to increase the flow rate in the SCV flow direction (communication direction) when the valve 4 is open, while suppressing an increase in the opening flow path area OA1 in the SCV flow direction (communication direction) and the opening flow path area OA2 in the bypass flow direction when the valve 4 is open. By changing the inclination shape of the inclined surface 54A, it is possible to adjust the flow rate of the SCV flow relative to the opening degree of the valve 4.

[0060] In some embodiments, the above-mentioned scroll connection valve 4 is configured such that, when the valve body 5 is in the fully closed position, a base end 542, which is the end of the inclined surface 54A on the seat surface 52 side, is located inside the junction flow path 26, as shown in FIG. 10, and when the valve body 5 is in the fully open position, the base end 542 of the inclined surface 54A is located inside the exhaust flow path 28.

[0061] In Case 3 in FIG. 8, the flow rate of the bypass flow relative to the opening degree of valve 4 can be increased, compared to Cases 1 and 2.

[0062] According to the above configuration, when the position of the valve element 5 changes from the fully closed position to the fully open position, the base end 542 of the inclined surface 54A moves from inside the junction passage 26 to inside the exhaust passage 28. In this case, the opening flow path area OA2 in the bypass flow direction when the valve 4 is open can be increased compared to a structure in which the base end 542 of the inclined surface 54A is located inside the junction passage 26 when the valve element 5 is in the fully open position.

[0063] 1, a turbine (double scroll turbine) 1 according to some embodiments includes the above-mentioned housing (double scroll turbine housing) 2 and a turbine wheel 3 rotatably accommodated in the housing 2. According to the above-mentioned configuration, the performance of the turbine 1 can be improved by improving the flow characteristics when the valve (scroll connection valve 4) is open.

[0064] Fig. 11 is a schematic diagram showing the configuration of a turbocharger according to one embodiment. As shown in Fig. 11, a turbocharger 10 according to some embodiments includes the above-mentioned double scroll turbine 1 driven by exhaust gas discharged from an engine 11, and a compressor 12 coaxially connected to the double scroll turbine 1 for supplying air compressed with rotation to the engine 11. According to the above configuration, the performance of the turbocharger 10 can be improved by improving the flow rate characteristics when the valve (scroll connection valve 4) is opened.

[0065] In this specification, expressions expressing relative or absolute configuration, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," do not only strictly represent such a configuration, but also represent a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions indicating that things are in an equal state, such as "identical," "equal," and "homogeneous," not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions describing shapes such as a rectangular shape or a cylindrical shape do not only refer to shapes such as a rectangular shape or a cylindrical shape in the strict geometric sense, but also refer to shapes that include uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. In addition, in this specification, the expressions "comprise," "include," or "have" a certain element are not exclusive expressions that exclude the presence of other elements.

[0066] The present disclosure is not limited to the above-described embodiments, and includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0067] The contents described in the above-mentioned embodiments can be understood, for example, as follows.

[0068] 1) A double scroll turbine housing (2) according to at least one embodiment of the present disclosure includes: A double scroll turbine housing (2) having two scroll passages (21, 22) formed therein, the two scroll passages (21, 22) include a first scroll passage (21) and a second scroll passage (22) formed in the same region as the first scroll passage (21) in the axial direction of the turbine (1), The double scroll turbine housing (2) is a connection-flow-path forming section (270) that forms a connection flow path (27) including a first branch flow path (24) branching from the first scroll flow path (21), a second branch flow path (25) branching from the second scroll flow path (22), and a junction flow path (26) where the first branch flow path (24) and the second branch flow path (25) join together and which communicates with an exhaust flow path (28) through which exhaust gas that has passed through the turbine (1) flows, via an exhaust flow-path side communication port (29); a valve element (5) having a seat portion (51) including a seat surface (52) capable of coming into contact with and being separated from the exhaust flow path-side communication port (29), the seat portion (51) being capable of opening and closing the exhaust flow path-side communication port (29), and a protrusion (53) protruding from the seat portion (51) toward the junction flow path (26), the protrusion (53) being capable of separating each of the first branch flow path (24) and the second branch flow path (25) in the junction flow path (26); and a valve rod (6) for rotating the valve element (5) about a valve axis (LC), A direction perpendicular to the seat surface (52) of the valve body (5) and away from the seat surface (52) is defined as a height direction (HD), The direction perpendicular to the height direction (HD) and the direction parallel to the valve axis (LC) is defined as a width direction (WD), In a case where a first flow path cross section (7) which is a flow path cross section perpendicular to a direction parallel to the valve axis (LC) at a connection position (242, 252) between at least one of the first branch flow path (24) and the second branch flow path (25) and the junction flow path (26) is divided into four regions (71, 72, 73, 74) by a first reference line (RL1) which extends in the height direction (HD) and passes through a centroid (RP) of the first flow path cross section (7) and a second reference line (RL2) which extends in the width direction (WD) and passes through the centroid (RP), In the case where, of the four regions (71, 72, 73, 74), a side closer to the seat surface (52) in the height direction (HD) than the centroid (RP) and farther from the valve axis (LC) in the width direction (WD) is defined as a first region (71), a side closer to the seat surface (52) in the height direction (HD) than the centroid (RP) and farther from the valve axis (LC) in the width direction (WD) is defined as a second region (72), a side closer to the seat surface (52) in the height direction (HD) than the centroid (RP) and farther from the valve axis (LC) in the width direction (WD) is defined as a third region (73), and a side closer to the seat surface (52) in the height direction (HD) than the centroid (RP) and farther from the valve axis (LC) in the width direction (WD) is defined as a fourth region (74), The fourth region (74) has a flow path area smaller than the first region (71), the second region (72), and the third region (73).

[0069] According to the above configuration 1), by making the flow passage area of ​​the fourth region (74) smaller than the flow passage areas of the other regions (the first region 71, the second region 72, and the third region 73), it is possible to suppress a rapid increase in the opening flow passage area in the flow passage cross section (7) when the valve (scroll connection valve 4) is opened (i.e., when the position of the valve element 5 is changed from the fully closed position to a predetermined open position), and it is possible to suppress a rapid increase in the flow rate of the exhaust gas passing through the junction flow passage (26). As a result, the SCV flow with respect to the opening degree of the valve (4) approaches a linear characteristic, and the controllability of the SCV flow can be improved. Therefore, according to the above configuration 1), it is possible to improve the flow rate characteristic when the valve (4) is opened.

[0070] 2) In some embodiments, the double scroll turbine housing (2) described in 1) above, Each of the third region (73) and the fourth region (74) includes at least an expanding region (73A, 74A) whose length in the width direction (WD) increases toward the valve shaft (LC) side as it approaches the seat surface (52) side in the height direction (HD).

[0071] According to the above configuration 2), the third region (73) and the fourth region (74) each include the widened region (73A, 74A), so that a rapid increase in the opening flow passage area in the flow passage cross section (7) when the valve (4) is open can be suppressed, and the SCV flow with respect to the opening degree of the valve (4) can be made closer to a linear characteristic. This improves the controllability of the SCV flow when the valve (4) is open.

[0072] 3) In some embodiments, the double scroll turbine housing (2) described in 2) above, The second region (72) includes at least a widening region (72A) whose length in the width direction (WD) increases toward the valve stem (LC) side as it approaches the seat surface (52) side in the height direction (HD).

[0073] According to the above configuration 3), since the second region (72) includes the widened region (72A), a rapid increase in the opening flow passage area in the flow passage cross section (7) when the valve (4) is open can be suppressed, and the SCV flow with respect to the opening degree of the valve (4) can be made closer to a linear characteristic, thereby improving the controllability of the SCV flow when the valve (4) is open.

[0074] 4) In some embodiments, the double scroll turbine housing (2) described in 2) above, Each of the first region (71) and the second region (72) includes a constant width region (71B, 72B) whose length in the width direction (WD) is constant, The constant width region (72B) of the second region (72) is formed in at least a part of the height direction (HD) where the constant width region (71B) of the first region (71) is formed.

[0075] According to the above configuration 4), since the first region (71) and the second region (72) include the constant width regions (71B, 72B), a rapid increase in the rate of increase in the open flow passage area in the flow passage cross section (7) when the valve (4) is open can be suppressed, and the SCV flow with respect to the opening degree of the valve (4) can be made closer to a linear characteristic. This improves the controllability of the SCV flow when the valve (4) is open.

[0076] According to the above configuration 4), the flow path width of the flow path cross section (7) is large in the range in the height direction (HD) where both the constant width region (71B) of the first region (71) and the constant width region (72B) of the second region (72) are formed. This makes it possible to increase the SCV flow when the valve (4) is in the large opening position. By changing the range in the height direction (HD) where both the constant width region (71B) of the first region (71) and the constant width region (72B) of the second region (72) are formed, it is possible to adjust the flow rate of the SCV flow in relation to the opening of the valve (4).

[0077] 5) In some embodiments, the double scroll turbine housing (2) according to any one of 1) to 4) above, Compared to a second flow path cross-section (8) of the junction flow path (26) perpendicular to a direction parallel to the valve axis (LC), the first flow path cross-section (7) is closed on a side away from the valve axis (LC) in the width direction (WD) and on a side away from the seat surface (52) in the height direction (HD).

[0078] According to the configuration of 5), the flow path cross section (7) at the connection position (242, 252) is closed on the side away from the valve axis (LC) in the width direction (WD) and on the side away from the seat surface (52) in the height direction (HD) as compared with the flow path cross section (8) perpendicular to the direction parallel to the valve axis (LC) of the junction flow path (26). In this case, it becomes easy to separate the first branch flow path (24) and the second branch flow path (25) by the valve (4), thereby improving the sealing performance when the valve (4) is fully closed.

[0079] 6) In some embodiments, the double scroll turbine housing (2) according to any one of 1) to 5) above, The protrusion (53) has, in a cross section perpendicular to a direction parallel to the valve axis (LC), a valve stem adjacent end surface (54) located on the valve stem (LC) side; a stem-distant end surface (55) located farther from the stem (LC) than the stem-proximal end surface (54); a bottom surface (56A) connecting a tip (541) of the valve stem proximal end surface (54) and a tip (551) of the valve stem distal end surface (55), The bottom surface (56A) is inclined such that the distance from the seat surface (52) becomes shorter from the tip (551) of the stem-rear end surface (55) toward the stem (LC).

[0080] According to the above configuration 6), by inclining the bottom surface (56A) of the protrusion (53) so that the distance from the seat surface (52) decreases from the tip (551) of the stem-rear end surface (55) toward the stem (LC), it is possible to increase the flow rate in the SCV flow direction (communication direction) when the valve (4) is open while suppressing an increase in the opening flow path area (OA1) in the SCV flow direction (communication direction) and the opening flow path area (OA2) in the bypass flow direction when the valve (4) is open. By changing the inclined shape of the bottom surface (56A), it is possible to adjust the flow rate of the SCV flow relative to the opening of the valve (4).

[0081] 7) In some embodiments, the double scroll turbine housing (2) according to any one of 1) to 5) above, The protrusion (53) has, in a cross section perpendicular to a direction parallel to the valve axis (LC), a valve stem adjacent end surface (54) located on the valve stem (LC) side; a stem-distant end surface (55) located farther from the stem (LC) than the stem-proximal end surface (54); a bottom surface (56) connecting a tip (541) of the valve stem proximal end surface (54) and a tip (551) of the valve stem distal end surface (55), The stem-proximal end face (54) has an inclined surface (54A) having a larger inclination angle than the stem-distal end face (55) opposed thereto across the axis (LB) of the protrusion (53).

[0082] According to the configuration of 7), the end face (54) of the protruding portion (53) near the valve stem has the inclined surface (54A), which makes it possible to increase the flow rate in the SCV flow direction (communication direction) when the valve (4) is open while suppressing an increase in the opening flow path area (OA1) in the SCV flow direction (communication direction) and the opening flow path area (OA2) in the bypass flow direction when the valve (4) is open. By changing the inclination shape of the inclined surface (54A), it is possible to adjust the flow rate of the SCV flow relative to the opening of the valve (4).

[0083] 8) In some embodiments, the double scroll turbine housing (2) described in 7) above, The scroll connection valve (4) is When the valve body (5) is in a fully closed position, a base end (542) which is an end of the inclined surface (54A) on the seat surface (52) side is configured to be located inside the junction flow path (26), and When the valve body (5) is in a fully open position, the base end (542) of the inclined surface (54A) is configured to be located inside the exhaust flow path (28).

[0084] According to the above configuration 8), when the position of the valve disc (5) changes from the fully closed position to the fully open position, the base end (542) of the inclined surface (54A) moves from inside the junction flow path (26) to inside the exhaust flow path (28). In this case, it is possible to increase the opening flow path area (OA2) in the bypass flow direction when the valve (4) is open, as compared with a structure in which the base end (542) of the inclined surface (54A) is located inside the junction flow path (26) when the valve disc (5) is in the fully open position.

[0085] 9) At least one embodiment of the double scroll turbine (1) according to the present disclosure includes: A double scroll turbine housing (2) according to any one of 1) to 8) above; and a turbine wheel (3) rotatably accommodated in the double scroll turbine housing (2).

[0086] According to the above configuration 9), the performance of the double scroll turbine (1) can be improved by improving the flow rate characteristics when the valve (scroll connection valve 4) is opened.

[0087] 10) The turbocharger (10) according to at least one embodiment of the present disclosure is A double scroll turbine (1) driven by exhaust gas discharged from an engine (11), comprising the double scroll turbine (1) described in 10) above; The double scroll turbine (1) is coaxially connected to a compressor (12) for supplying compressed air to the engine (11) as the turbine rotates.

[0088] According to the above configuration 10), the performance of the turbocharger (10) can be improved by improving the flow rate characteristics when the valve (scroll connection valve 4) is opened. [Explanation of symbols]

[0089] 1 Double scroll turbine 2 Double scroll turbine housing 3. Turbine Wheel 4 Scroll Connection Valve 5 Valve body 6 Valve stem 7,8 Flow passage cross section 10. Turbocharger 11 Engine 12 Compressor 21 First scroll passage 22 Second scroll passage 23 Nozzle flow path 24 First branch channel 25 Second branch channel 26 Confluence 27 Connecting Channel 28 Exhaust passage 29 Exhaust passage side communication port 51 Seat section 52 Seat surface 53 Protrusion 54 End face near valve stem 55 Valve stem far side end face 56 Bottom 71 First area 72 Second area 73 Third area 74 4th area 75 Hypotenuse near the valve stem 76 Distal side of valve stem 77 Bottom 78 Right side 210 First scroll passage forming section 220 Second scroll passage forming section 270 Connection flow path forming section CR1 1st range CR2 2nd range HD Height direction LA,LB,LC axis line LC valve stem OA1,OA2 Opening flow path area RL1 First Reference Line RL2 2nd reference line RP centroid WD Width direction

Claims

1. A double scroll turbine housing having two scroll passages formed therein, the two scroll passages include a first scroll passage and a second scroll passage formed in the same region as the first scroll passage in the axial direction of the turbine, The double scroll turbine housing comprises: a connection passage forming section that forms a connection passage including a first branch passage branching from the first scroll passage, a second branch passage branching from the second scroll passage, and a junction passage where the first branch passage and the second branch passage join together and which communicates with an exhaust passage through which exhaust gas that has passed through the turbine flows, via an exhaust passage side communication port; a valve body having a seat portion including a seat surface that can be brought into contact with and separated from the exhaust flow path side communication port and that can open and close the exhaust flow path side communication port, and a protrusion that protrudes from the seat portion toward the junction flow path and that can separate each of the first branch flow path and the second branch flow path in the junction flow path, and a valve rod for rotating the valve body about a valve axis, A direction perpendicular to the seat surface of the valve body and away from the seat surface is defined as a height direction, A direction perpendicular to the height direction and a direction parallel to the valve axis is defined as a width direction, When a first flow passage cross section, which is a flow passage cross section perpendicular to a direction parallel to the valve axis at a connection position between at least one of the first branch flow passage and the second branch flow passage and the junction flow passage, is divided into four regions by a first reference line extending in the height direction and passing through a centroid of the first flow passage cross section and a second reference line extending in the width direction and passing through the centroid, Among the four regions, a side closer to the seat surface in the height direction than the centroid and farther from the valve shaft in the width direction is defined as a first region, a side closer to the seat surface in the height direction than the centroid and farther from the valve shaft in the width direction is defined as a second region, a side closer to the seat surface in the height direction than the centroid and farther from the valve shaft in the width direction is defined as a third region, and a side closer to the seat surface in the height direction than the centroid and farther from the valve shaft in the width direction is defined as a fourth region, The fourth region has a flow path area smaller than those of the first region, the second region, and the third region. Double scroll turbine housing.

2. Each of the third region and the fourth region includes at least a widening region in which the length in the width direction increases toward the valve shaft side as the length in the height direction approaches the seat surface side. The double scroll turbine housing of claim 1 .

3. The second region includes at least a widening region in which the length in the width direction increases toward the valve shaft side as the length in the height direction approaches the seat surface side. The double scroll turbine housing according to claim 2 .

4. Each of the first region and the second region includes a constant width region having a constant length in the width direction, The constant width region of the second region is formed in at least a part of the height direction in which the constant width region of the first region is formed. The double scroll turbine housing according to claim 2 .

5. The first flow path cross section is closed on a side farther from the valve axis in the width direction and on a side farther from the seat surface in the height direction, compared to a second flow path cross section which is a flow path cross section of the merging flow path perpendicular to a direction parallel to the valve axis. A double scroll turbine housing according to any one of claims 1 to 4.

6. The protrusion has a cross section perpendicular to a direction parallel to the valve axis, a valve stem adjacent end surface located on the valve stem side; a stem distal end surface located farther from the stem than the stem proximate end surface; a bottom surface connecting a tip of the valve stem proximal end surface and a tip of the valve stem distal end surface, The bottom surface is inclined such that the distance from the seat surface becomes shorter from the tip of the valve stem distal end surface toward the valve stem. A double scroll turbine housing according to any one of claims 1 to 5.

7. The protrusion has a cross section perpendicular to a direction parallel to the valve axis, a valve stem adjacent end surface located on the valve stem side; a stem distal end surface located farther from the stem than the stem proximate end surface; a bottom surface connecting a tip of the valve stem proximal end surface and a tip of the valve stem distal end surface, the valve stem proximate end surface has an inclined surface having a larger inclination angle than the valve stem distal end surface opposed to the valve stem proximate end surface across the axis of the protrusion; A double scroll turbine housing according to any one of claims 1 to 5.

8. The scroll connection valve is When the valve body is in a fully closed position, a base end of the inclined surface on the seat surface side is positioned inside the junction flow path, and When the valve body is in a fully open position, the base end of the inclined surface is positioned inside the exhaust flow path. A double scroll turbine housing according to claim 7.

9. A double scroll turbine housing according to any one of claims 1 to 8; a turbine wheel rotatably accommodated in the double scroll turbine housing; Double scroll turbine.

10. A double scroll turbine driven by exhaust gas discharged from an engine, comprising: the double scroll turbine according to claim 9; a compressor that is coaxially connected to the double scroll turbine and that supplies compressed air to the engine as the turbine rotates. Supercharger.

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