Wastegate valve assembly, turbine and turbocharger

Abstract

Wastegate valve device (100) arranged on a bypass channel (110) formed within a turbine housing (5) containing a turbine wheel (3) bypassing a turbine (30) of a turbocharger (1) arranged on an exhaust channel of an engine, comprising: a valve seat surface (113) formed at an outlet (111) of the bypass channel (110); and a wastegate valve body (150) which supports a support arm (120) which is rotatably supported about an axis (AX), and a valve body (130), which is supported by the support arm (120), wherein the valve body (130) is configured to come into and out of contact with the valve seat surface (113) according to a rotation of the support arm (120), wherein the valve seat surface (113) is inclined orthogonal to an axial direction (BPAX) of the bypass channel (110) with respect to a direction of the axis (AX); wherein the bypass channel (110) connects a spiral flow channel (7a) and an exhaust channel (171) for bypassing the turbine wheel (3); and wherein a center of rotation of the valve body (130), as seen from the direction of the axis (AX), is arranged radially outside a center line (Cbp) of the bypass channel (110) and radially outside an outermost end of a spiral flow channel generating section (7) that forms the spiral flow channel (7a).

Description

TECHNICAL AREA

[0001] The present disclosure relates to a wastegate valve device, a turbine and a turbocharger. BACKGROUND

[0002] A turbocharger may be equipped with a wastegate valve to suppress excessive increases in boost pressure. The wastegate valve is configured to regulate the amount of exhaust gas flowing to a turbocharger turbine by opening and closing a wastegate flow channel, which acts as a bypass channel that circumvents the turbine. Citation list of patent literature

[0003] Patent Document 1: JP2018-127989A

[0004] US 2017 / 0152793A1 concerns a wastegate valve for a bypass path for a turbocharger in an internal combustion engine. The wastegate valve comprises a valve seat defining a plane that is not orthogonal to the main flow axis of the gases flowing along the bypass path, and a valve element that can pivot from an open position to a closed position, the valve element being seated on the valve seat in the closed position and positioned slightly open to direct gases exiting the bypass path onto a front surface of a catalyst monolith to heat the monolith.

[0005] US 2015 / 0 016 963 A1 relates to a turbine comprising a turbine casing defining a turbine inlet upstream of a turbine wheel and a turbine outlet downstream of the turbine wheel, a wastegate channel connecting the turbine inlet and outlet, and a wastegate valve comprising a movable valve element. The wastegate valve has an open and a closed state. The valve element is mounted on an actuating element that extends through an actuating line of the turbine casing and is movable such that it moves the wastegate valve between the open and closed states. The turbine further comprises a sealing assembly configured to provide a seal that substantially prevents gas from entering the actuator line from the turbine outlet.

[0006] DE 10 2018 115 380 A1 relates to an exhaust system for an internal combustion engine, which is equipped with an exhaust gas turbine charger (turbocharger) for driving a centrifugal compressor using exhaust gas energy, an exhaust gas purification catalyst arranged on the downstream side of a turbine of the turbocharger, and an exhaust gas sensor arranged between the turbine and the exhaust gas purification catalyst. SUMMARY Technical Problem

[0007] For example, in a turbocharger used in a vehicle, such as an automobile, the control of a wastegate valve's opening degree traditionally primarily involved controlling whether the wastegate valve should be fully open or fully closed, depending on whether a parameter related to turbocharger overspeed, such as compressor outlet pressure, exceeded a preset threshold. However, in recent years, there has been an increasing demand for precise control of boost pressure. Consequently, there is also an increasing demand for precise control of the exhaust gas flow rate bypassing the turbine.

[0008] In light of the foregoing, an object of at least one embodiment of the present disclosure is to improve the control accuracy of the flow rate of the exhaust gas bypassing the turbine. Solution to the problem

[0009] (1) A wastegate valve device according to at least one embodiment of the present disclosure is a wastegate valve device arranged on a bypass channel formed within a turbine housing containing a turbine wheel, which bypasses a turbine of a turbocharger arranged on an exhaust port of an engine. The wastegate valve device comprises: a valve seat surface formed at an outlet of the bypass channel; and a wastegate valve body comprising a support arm rotatably supported about an axis and a valve body supported by the support arm, the valve body being configured to come into and out of contact with the valve seat surface according to a rotation of the support arm. The valve seat surface is inclined in a direction orthogonal to an axial direction of the bypass channel, viewed from a direction of the axis.In particular, the bypass channel connects a spiral flow channel and an exhaust channel to bypass the turbine wheel, wherein a center of rotation of the valve body, viewed from the direction of the axis, is arranged radially outside a center line of the bypass channel and radially outside an outermost end of a spiral flow channel generating section that forms the spiral flow channel.

[0010] (2) A turbine according to at least one embodiment of the present disclosure includes the wastegate valve device with the configuration described above (1).

[0011] (3) A turbocharger according to at least one embodiment of the present disclosure includes the turbine with the aforementioned configuration (2). Beneficial effects

[0012] According to at least one embodiment of the present disclosure, it is possible to improve the control accuracy of a flow rate of an exhaust gas that bypasses a turbine. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a cross-sectional view showing an example of a turbocharger according to some embodiments. Fig. Figure 2 is a perspective view showing the appearance of a turbine wheel according to some embodiments. Fig. Figure 3 is a view that schematically shows the partial cross-section of a turbine according to one embodiment. Fig. 4 is a partially enlarged view of Fig. 3. Fig. Figure 5 is a view that schematically shows the partial cross-section of the turbine according to another embodiment. Fig. Figure 6 is a diagram showing an example of flow rate characteristics in a wastegate valve device according to some embodiments. DETAILED DESCRIPTION

[0013] Embodiments of the present disclosure are described below with reference to the accompanying drawings. However, unless specifically identified, dimensions, materials, shapes, relative positions, and the like of components described or shown in the drawings as embodiments are intended to be interpreted as illustrative only and not to limit the scope of the present disclosure. For example, an expression of a relative or absolute arrangement, such as "in one direction," "along one direction," "parallel," "orthogonal," "centered," "concentric," and "coaxial," is not to be interpreted as indicating only the arrangement in a strict literal sense, but also as encompassing a state in which the arrangement is displaced by a tolerance or by an angle or distance, thereby making it possible to achieve the same function.For example, an expression of an equal state, such as "equal," "identical," and "uniform," should not be interpreted as indicating only the state in which the feature is strictly equal, but should also include a state in which there is a tolerance or a difference that can still achieve the same function. Furthermore, for example, an expression of a shape, such as a rectangular shape or a tubular shape, should not be interpreted as referring only to the geometrically strict form, but should also include a shape with irregularities or chamfered corners within the range in which the same effect can be achieved. On the other hand, the expressions "comprising," "including," "exhibiting," "containing," and "representing a constituent component" are not exclusive expressions that exclude the presence of other constituent components. (Overall configuration of turbocharger 1)

[0014] Fig. Figure 1 is a cross-sectional view showing an example of a turbocharger 1 according to some embodiments. The turbocharger 1 according to some embodiments is an exhaust gas turbocharger for charging the intake air of an engine, which is mounted on a vehicle, such as an automobile, and is arranged on an exhaust port of the engine (not shown). The turbocharger 1 comprises a turbine wheel 3 and a compressor wheel 4, which are coupled to each other by a rotor shaft 2 as a rotating shaft, a housing (turbine housing) 5 for rotatably receiving the turbine wheel 3, and a housing (compressor housing) 6 for rotatably receiving the compressor wheel 4. The turbine housing 5 comprises a spiral flow channel generation section 7, which has an internal spiral flow channel 7a, a turbine wheel housing section 53 for receiving the turbine wheels 3, and an exhaust channel formation section 55 for forming an exhaust channel 171, which is formed downstream of the turbine wheels 3.The compressor housing 6 contains a spiral part 8 which has a spiral flow channel 8a inside.

[0015] A turbine 30 according to some embodiments includes the turbine wheel 3 and the housing 5. A compressor 40 according to some embodiments includes the compressor wheel 4 and the housing 6. (Turbine wheel 3)

[0016] Fig. Figure 2 is a perspective view showing the appearance of the turbine wheel 3 according to some embodiments. Fig. Figure 3 is a view that schematically shows the partial cross-section of the turbine 30 according to one embodiment.

[0017] Fig. 4 is a partially enlarged view of Fig. 3. Fig. Figure 5 is a view that schematically shows the partial cross-section of turbine 30 according to another embodiment. Fig. 3 and Fig. Figure 4 shows a case in which a wastegate valve device 100, which is described later, has a range in which the valve opening degree is relatively small. Furthermore, it shows Fig. 5 a case in which the wastegate valve device 100 is completely closed.

[0018] The turbine wheel 3 according to some embodiments is an impeller coupled to the rotor shaft 2 and rotated about an axis of rotation AXW. The turbine wheel 3 according to some embodiments includes a hub 31 with a hub surface 32 inclined with respect to the axis of rotation AXW, and a plurality of blades (rotor blades) 33 arranged on the hub surface 32 in a cross-section along the axis of rotation AXW. The [unclear text] Fig. 1 to Fig. 3 and Fig. Turbine wheel 3 shown in Figure 5 is a radial turbine, but it can also be a mixed-flow turbine. Fig. An arrow R indicates the direction of rotation of the turbine wheel 3. The majority of blades 33 are arranged at intervals in the circumferential direction of the turbine wheel 3.

[0019] Although the perspective view illustration has been omitted, the compressor wheel 4, according to some embodiments, also has the same configuration as the turbine wheel 3, according to some embodiments. That is, the compressor wheel 4, according to some embodiments, is an impeller coupled to the rotor shaft 2 and rotated about the axis of rotation AXW. The compressor wheel 4, according to some embodiments, includes a hub 41 with a hub surface 42 inclined with respect to the axis of rotation AXW, and a plurality of blades (rotor blades) 43 arranged on the hub surface 42 in a cross-section along the axis of rotation AXW. The plurality of blades 43 are arranged at intervals in the circumferential direction of the compressor wheel 4.In the following description, the extension direction of the axis of rotation AXW can simply be referred to as the axial direction, the radial direction centered on the axis of rotation AXW can simply be referred to as the radial direction, and the circumferential direction centered on the axis of rotation AXW can simply be referred to as the circumferential direction.

[0020] In the turbocharger 1 configured in this way, an exhaust gas, serving as a working fluid for the turbine 30, flows from a leading edge 36 to a trailing edge 37 of the turbine wheel 3. Consequently, the turbine wheel 3 is rotated, and the compressor wheel 4 of the compressor 40, which is coupled via the rotor shaft 2, is also rotated. Consequently, intake air flowing in from an inlet section 40a of the compressor 40 is compressed by the compressor wheel 4 as it flows from a leading edge 46 to a trailing edge 47 of the compressor wheel 4. (Wastegate valve device 100)

[0021] As in the Fig. 3 to Fig. As shown in Figure 5, according to some embodiments, the turbine 30 includes the wastegate valve device 100, which is arranged on a bypass channel 110 that bypasses the turbine 30. As shown in the Fig. 3 to Fig. As shown in Figure 5, the wastegate valve device 100, according to some embodiments, comprises a valve seat surface 113 formed at an outlet 111 of the bypass channel 110, and a wastegate valve body 150. The wastegate valve body 150, according to some embodiments, includes a support arm 120 and a valve body 130. In the wastegate valve body 150, according to some embodiments, the support arm 120 is rotatably supported about an axis AX. The support arm 120 may be mounted on a rotary shaft 121 configured to rotate about the axis AX. In the wastegate valve body 150, according to some embodiments, the valve body 130 is supported by the support arm 120 and is configured to come into and out of contact with the valve seat surface 113 according to the rotation of the support arm 120. In some embodiments, the valve body 130 is a swivel valve configured to be pivotable according to the rotation of the support arm 120.

[0022] As in the Fig. 3 to Fig. As shown in Figure 5, in the wastegate valve device 100 according to some embodiments, the valve seat surface 113 is inclined in a direction orthogonal to an axial direction BPAX ​​of the bypass channel 110, as viewed from a direction of the axis AX described above. The axial direction BPAX ​​of the bypass channel 110 is a direction of extension of a centerline Cbp of the bypass channel 110. In the following description, the direction orthogonal to the axial direction BPAX ​​of the bypass channel 110 can simply be referred to as an orthogonal direction BPORTH.

[0023] As in the Fig. 3 to Fig. As shown in Figure 5, the wastegate valve device 100 is arranged in some embodiments in a region radially outside the turbine wheel 3 relative to the leading edge 36 of the turbine wheel 3. Furthermore, as shown in the Fig. 3 to Fig. As shown in Figure 5, in the wastegate valve device 100, according to some embodiments, the axis of rotation AXW and the centerline Cbp of the bypass channel 110 are parallel. As shown in the Fig. 3 to Fig. As shown in Figure 5, in the wastegate valve device 100 according to some embodiments, the axis AX, which is a center of rotation of the rotary shaft 121 and the support arm 120, is arranged radially outside the turbine wheel 3 relative to the center line Cbp of the bypass channel 110.

[0024] In the wastegate valve device 100 according to some embodiments, when a swivel angle θv (see Fig. 5) As the angle of rotation of the valve body 130, centered on the axis AX described above, which is the center of rotation of the support arm 120, increases, the size of the gap between the valve body 130 and the valve seat surface 113, that is, the distance between the valve body 130 and the valve seat surface 113, also increases. Here, the pivot angle θv of the valve body 130 increases when the valve body 130 and the valve seat surface 113 are separated from each other, with the angle of the valve body 130 when the valve body 130 and the valve seat surface 113 are in contact, that is, when the wastegate valve device 100 is fully closed, being a reference (0 degrees). Furthermore, in the following description, the pivot angle θv of the valve body 130 can be referred to as the valve opening degree θv.

[0025] Fig. Figure 6 is a diagram showing an example of flow rate characteristics in the wastegate valve device 100 according to some embodiments. In the diagram of Fig. Figure 6 shows the horizontal axis representing the valve opening degree θv and the vertical axis representing the ratio of the amount of exhaust gas flowing through the bypass channel 110 to the amount of exhaust gas flowing through the bypass channel 110 when the wastegate valve device 100 is fully open (throughflow rate / throughflow rate when fully open). In the diagram of Fig. Figure 6 is a flow rate property A, indicated by a thick solid line, an example of a flow rate property in the wastegate valve device 100 according to some embodiments. In the diagram of Fig. 6 is a flow rate property B, indicated by a thin solid line, an example of an ideal flow rate property. In the diagram of Fig. 6 is a flow rate property C, indicated by a dashed line, an example of a flow rate property in a conventional wastegate valve device.

[0026] In a conventional wastegate valve device, the magnitude of the change in the amount of exhaust gas flowing through the wastegate valve per unit valve opening degree is greater in a range where the valve opening degree θv is relatively small than in a range where the valve opening degree θv is relatively large. Therefore, the control accuracy of the exhaust gas flow in the range where the valve opening degree θv is relatively small tends to be lower than in the range where the valve opening degree θv is relatively large. Therefore, in the range where the valve opening degree θv is relatively small, it is desirable for the magnitude of the change in the amount of exhaust gas flowing through the wastegate valve device per unit valve opening degree to be smaller than that of the conventional wastegate valve device.

[0027] With the wastegate valve device 100 according to some embodiments described in the Fig. 3 to Fig. As shown in Figure 5, in the region where the valve opening degree θv is relatively small, even with the same valve opening degree θv, the distance between the valve body 130 and the valve seat surface 113 decreases compared to a case where the valve seat surface 113 is not inclined with respect to the orthogonal direction BPORTH. Therefore, in the region where the valve opening degree θv is relatively small, even with the same valve opening degree θv, a neck region Ss between the valve body 130 and the valve seat surface 113 decreases.

[0028] The throat area Ss between the valve body 130 and the valve seat surface 113 is an opening through which exhaust gas flows between the valve body 130 and the valve seat surface 113. More precisely, this is as follows. A surface of the valve body 130 that blocks the outlet 111 of the bypass channel 110 when the wastegate valve device 100 is fully closed is referred to as a closing surface 131. The throat area Ss described above is a value obtained by integrating a distance Lv from an inner circumferential edge 115 of the bypass channel 110 at the outlet 111 of the bypass channel 110 to the closing surface 131 along the inner circumferential edge 115.

[0029] Therefore, with the wastegate valve device 100 according to some embodiments, which are in the Fig. 3 to Fig. As shown in Figure 5, in the region where the valve opening degree θv is relatively small, it is possible to reduce the amount of change in the throat area Ss per unit valve opening degree compared to the case where the valve seat surface 113 is not inclined with respect to the orthogonal direction BPORTH. Therefore, with the wastegate valve device 100 according to some embodiments shown in the Fig. 3 to Fig. As shown in Figure 5, in the range where the valve opening degree θv is relatively small, it is possible to reduce the amount of change in the quantity of exhaust gas flowing through the wastegate valve device 100 (bypass channel 110) per unit valve opening degree compared to the case where the valve seat surface 113 is not inclined with respect to the orthogonal direction BPORTH. Accordingly, it is possible to improve the control accuracy of the exhaust gas quantity in the range where the valve opening degree θv is relatively small. (Regarding the inclination direction of the valve seat surface 113)

[0030] For example, in the wastegate valve device 100, which is in the Fig. 3 and Fig. As shown in section 4, the valve seat surface 113 faces a downstream side (the right side in the Fig. 3 and Fig. 4) of the bypass channel 110 inclined radially inwards of the turbine wheel 3 (a direction which is parallel to the axis of rotation AXW in the Fig. 3 and Fig. 4 approaches).

[0031] That is, in the wastegate valve device 100 according to some embodiments, for example as in the Fig. 3 and Fig. As shown in Figure 4, a region 113a of the valve seat surface 113 is arranged on one side across the centerline Cbp of the bypass channel 110, preferably upstream of the bypass channel 110 relative to a region 113b arranged on the other side, as viewed from the direction of the axis AX. The axis AX, which is the center of rotation of the valve body 130, is preferably arranged on the one side across the centerline Cbp as described above, as viewed from the direction of the axis AX. The one side described above is the radially outer side of the turbine wheel 3 relative to the centerline Cbp. The other side described above is the radially inner side of the turbine wheel 3 relative to the centerline Cbp.

[0032] For example, in the wastegate valve device 100, which is in the Fig. 3 and Fig. As shown in Figure 4, the valve seat surface 113 is inclined with respect to the orthogonal direction BPORTH such that the area 113a, which is arranged on the one side described above above above the center line Cbp of the bypass channel 110, is arranged upstream of the bypass channel 110 relative to the area 113b, which is arranged on the other side described above.Therefore, in the state in which the valve body 130 and the valve seat surface 113 are in contact with each other (when the wastegate valve device 100 is completely closed) and at least in the region in which the valve opening degree θv is relatively small, as with the valve seat surface 113, the closing surface 131 is inclined with respect to the orthogonal direction BPORTH such that a region located on the one side described above above above the center line Cbp of the bypass channel 110 is located upstream of the bypass channel 110 relative to a region located on the other side described above.Therefore, at least in the area where the valve opening degree θv is relatively small, the exhaust gas flowing through the bypass channel 110 and being expelled from the outlet 111 of the bypass channel 110 is guided from the one side described above across the center line Cbp of the bypass channel 110 to the other side described above along the closing surface 131 described above, as indicated by an arrow a in . Fig. 3 indicated.

[0033] Among the areas outside the bypass channel 110, in the area on the side described above, across the centerline Cbp of the bypass channel 110, there exists the support arm 120, the pivot shaft 121, or the like. Therefore, among the areas outside the bypass channel 110, in the area on the other side described above, across the centerline Cbp of the bypass channel 110, it is more likely than in the area on the side described above that the number of elements, etc., decreases, which can impair the flow of the exhaust gas expelled from the outlet 111 of the bypass channel 110. Therefore, for example, with the in the Fig. 3 and Fig. 4 wastegate valve device 100 shown, since the exhaust gas flowing through the bypass channel 110 and being expelled from the outlet 111 of the bypass channel 110 is guided from the one side described above over the center line Cbp of the bypass channel 110 to the other side described above, the flow of the exhaust gas after it has been expelled from the outlet 111 of the bypass channel 110 is smooth, which makes it possible to suppress a pressure loss. (Regarding the position of the AX axis)

[0034] For example, there exists in the in the Fig. 3 and Fig. 4 Wastegate valve device 100 shown, as in Fig. As shown in Figure 4, the axis AX, which is the center of rotation of the valve body 130, is preferably located further away from the center line Cbp described above relative to a normal N to the valve seat surface 113, which passes through an end section 135 of the valve body 130. This end section 135 is located on one side of the valve seat surface 113 and on the other side described above across the center line Cbp, as viewed from the direction of the axis AX. Consequently, as the valve opening degree θv increases from the state in which the valve body 130 and the valve seat surface 113 are in contact with each other, i.e., the state in which the wastegate valve device 100 is completely closed, the end section 135 described above moves away from the valve seat surface 113. Therefore, it is possible to avoid interference between the end section 135 described above and the valve seat surface 113 when the valve body 130 pivots.An arc drawn by a single-point catenary line lying on the axis AX in . Fig. 4 is centered, is a location Lo of the end section 135 described above when the valve body 130 pivots. (Regarding another embodiment of the inclination direction of the valve seat surface 113)

[0035] For example, in the wastegate valve device 100, which is in Fig. As shown in section 5, the valve seat surface 113 faces an upstream side (the left side in Fig. 5) of the bypass channel 110 inclined radially inwards of the turbine wheel 3 (a direction which is parallel to the axis of rotation AXW in Fig. 5 approaches). That is, in the wastegate valve device 100 according to another embodiment, for example as in Fig. As shown in Figure 5, in the valve seat surface 113, the area 113b of the valve seat surface 113, which is located on the other side across the centerline Cbp of the bypass channel 110, can be arranged upstream of the bypass channel 110 relative to the area 113a, which is located on one side, as viewed from the direction of the axis AX. The axis AX, which is the center of rotation of the valve body 130, can be arranged on one side across the centerline Cbp as described above, as viewed from the direction of the axis AX.

[0036] For example, in the wastegate valve device 100, which is in Fig. As shown in Figure 5, the valve seat surface is inclined in the direction orthogonal to the axial direction of the bypass channel such that the region 113b, which is located on the other side described above above, above the center line Cbp of the bypass channel 110, is located upstream of the bypass channel relative to the region 113a, which is located on the other side.Therefore, in the state in which the valve body 130 and the valve seat surface 113 are in contact with each other (when the wastegate valve device 100 is completely closed) and at least in the region in which the valve opening degree θv is relatively small, as with the valve seat surface 113, the closing surface 131 is inclined with respect to the orthogonal direction BPORTH such that the region which is arranged on the other side described above above across the center line Cbp of the bypass channel 110 is arranged upstream of the bypass channel relative to the region which is arranged on the one side described above.Therefore, at least in the area where the valve opening degree θv is relatively small, the exhaust gas flowing through the bypass channel 110 and being expelled from the outlet 111 of the bypass channel 110 is guided from the other side described above across the center line Cbp of the bypass channel 110 to the one side described above along the closing surface 131 described above, as indicated by an arrow b in . Fig. 5 is indicated.

[0037] Among the areas outside the bypass channel 110, in the area on one side across the centerline Cbp of the bypass channel 110, there exists an element, such as the support arm 120 or the rotating shaft 121, which can impede the flow of the exhaust gas expelled from the outlet 111 of the bypass channel 110. However, due to design constraints or the like, it is also conceivable that there may be a case in which it is better to direct the exhaust gas expelled from the outlet 111 of the bypass channel 110 more towards the area on the one side described above across the centerline Cbp of the bypass channel 110 than towards the area on the other side described above. Even in such a case, for example, with the Fig. 5 wastegate valve device 100 shown, since the exhaust gas flowing through the bypass channel 110 and being expelled from the outlet 111 of the bypass channel 110 is guided from the other side over the center line Cbp of the bypass channel 110 to one side, an impairment of the flow of the exhaust gas after it has been expelled from the outlet 111 of the bypass channel 110 is suppressed, which makes it possible to suppress the pressure loss.

[0038] Since, as described above, the turbine 30 according to some embodiments includes the wastegate valve device 100, which has any of the configurations described above, it is possible to improve the control accuracy of the exhaust gas quantity in the range where the valve opening degree is relatively small. (With regard to discharge duct 171)

[0039] In the turbine 30 according to some embodiments, such as in Fig. As shown in Figure 3, the exhaust channel 171 includes an exhaust channel main flow region 173 and a confluence region 175. The exhaust channel main flow region 173 is adjacent to the bypass channel 110 on the other side described above, across the centerline Cbp of the bypass channel 110 (the radially inner side of the turbine wheel 3 relative to the centerline Cbp), as viewed from the direction of the axis AX. The confluence region 175 is a region in which the exhaust gas expelled from the outlet 111 of the bypass channel 110 is concentrated, as indicated by an arrow c in Figure 3. Fig. 3, and combine the exhaust gas flowing through the main flow area of ​​the exhaust duct 173 as indicated by an arrow d.

[0040] Since the in Fig. 3 turbines 30 shown in the Fig. 3 and Fig. As described above, the wastegate valve device 100, shown in Figure 4, includes the following: the exhaust gas flowing through the bypass channel 110 and expelled from the outlet 111 of the bypass channel 110 is guided from one side described above, across the center line Cbp of the bypass channel 110, to the other side described above along the closing surface 131 of the valve body 130, as indicated by arrow a in Figure 4. Fig. 3. Thus, the exhaust gas flowing through the bypass channel 110 and expelled from the outlet 111 of the bypass channel 110 easily merges with the exhaust gas flowing through the main flow area of ​​the exhaust channel 173 in the confluence area 175, and a disturbance of the flow of the exhaust gas flowing through the exhaust channel 171 is suppressed, which makes it possible to suppress the pressure loss of the exhaust gas in the exhaust channel 171.

[0041] In the turbine 30 according to some embodiments, for example as in Fig.As shown in Figure 3, the angle difference Δθ between an extension direction to a downstream side of the exhaust channel main flow area 173 (the extension direction of arrow c) and an extension direction of the valve seat surface 113 from the one side described above across the center line Cbp of the bypass channel 110 to the other side described above on the valve seat surface 113 is preferably less than 90 degrees, as viewed from the direction of the axis AX.

[0042] If the angle difference Δθ described above is less than 90 degrees, the exhaust gas flowing through the bypass channel 110 and expelled from the outlet 111 of the bypass channel 110 merges more easily with the exhaust gas flowing through the main flow area of ​​the exhaust channel 173 in the confluence area 175, and disturbance of the flow of the exhaust gas flowing through the exhaust channel 171 is further suppressed, which makes it possible to further suppress the pressure loss of the exhaust gas in the exhaust channel 171.

[0043] The direction of extension of the valve seat surface 113 from the side described above, across the centerline Cbp of the bypass channel 110, to the other side described above, is preferably directed towards a catalyst (not shown) for treating the exhaust gas, as viewed from the direction of the axis AX. Consequently, the exhaust gas flowing through the bypass channel 110 and expelled from the outlet 111 of the bypass channel 110 flows easily to the catalyst. Thus, the catalyst is easily heated by the exhaust gas flowing through the bypass channel 110 and expelled from the outlet 111 of the bypass channel 110, which makes it possible to shorten the time required to raise the temperature of the catalyst to a temperature suitable for treating the exhaust gas.

[0044] Since the turbocharger 1 includes the turbine 30 described above according to some embodiments, it is possible to improve the control accuracy of the boost pressure.

[0045] The contents described in the above embodiments are to be understood, for example, as follows. (1) The wastegate valve device 100 according to at least one embodiment of the present disclosure is a wastegate valve device arranged on a bypass channel 110, which is formed within a turbine housing 5 containing a turbine wheel 3, bypassing a turbine 30 of a turbocharger 1 arranged on an exhaust port of an engine. The wastegate valve device 100 according to at least one embodiment of the present disclosure comprises a valve seat surface 113 formed at an outlet 111 of the bypass channel 110; and a wastegate valve body 150 comprising a support arm 120 rotatably supported about an axis AX, and a valve body 130 supported by the support arm 120, the valve body 130 being configured to come into and out of contact with the valve seat surface 113 according to the rotation of the support arm 120.In the wastegate valve device 100 according to at least one embodiment of the present disclosure, the valve seat surface 113 is inclined orthogonally with respect to an axial direction BPAX ​​of the bypass channel 110 in a direction (orthogonal direction BPORTH), as viewed from a direction of the axis AX described above. In particular, the bypass channel 110 connects a spiral flow channel 7a and an exhaust channel 171 for bypassing the turbine wheel 3, wherein a center of rotation of the valve body 130, viewed from the direction of the axis AX, is arranged radially outside a center line Cbp of the bypass channel 110 and radially outside an outermost end of a spiral flow channel generating section 7 that forms the spiral flow channel 7a.

[0046] With the above configuration (1), in the range where the valve opening degree θv is relatively small, even with the same valve opening degree θv, the distance between the valve body 130 and the valve seat surface 113 decreases compared to the case where the valve seat surface 113 is not inclined with respect to the orthogonal direction BPORTH. Therefore, with the above configuration (1), in the range where the valve opening degree θv is relatively small, it is possible to reduce the amount of change in the quantity of exhaust gas flowing through the wastegate valve device 100 (bypass channel 110) compared to the case where the valve seat surface 113 is not inclined with respect to the orthogonal direction BPORTH. Accordingly, it is possible to improve the control accuracy of the exhaust gas quantity in the range where the valve opening degree θv is relatively small.

[0047] (2) In some embodiments, in the above configuration (1), a region 113a of the valve seat surface 113 is arranged on one side across a centerline Cbp of the bypass channel 110, preferably upstream of the bypass channel 110 relative to a region 113b arranged on the other side, as viewed from the direction of the axis AX described above. The axis AX, which is a center of rotation of the valve body 130, is preferably arranged on the one side across the centerline Cbp described above, as viewed from the direction of the axis AX described above.

[0048] With the above configuration (2), since the exhaust gas flowing through the bypass channel 110 and being expelled from the outlet 111 of the bypass channel 110 is guided from the one side described above across the center line Cbp of the bypass channel 110 to the other side described above, the flow of the exhaust gas after it has been expelled from the outlet 111 of the bypass channel 110 becomes smooth, which makes it possible to suppress the pressure loss.

[0049] (3) In some embodiments, in the above configuration (2), the center of rotation (axis AX) described above preferably exists in a region further from the center line Cbp described above relative to a normal N to the valve seat surface 113, which passes through an end section 135 of the valve body 130, which is arranged on one side of the valve seat surface 113 and on the one side described above across the center line Cbp described above, as viewed from the direction of the axis AX described above.

[0050] With the above configuration (3), as the valve opening degree θv increases from the state in which the valve body 130 and the valve seat surface 113 are in contact with each other (when the wastegate valve device 100 is fully closed), the end section 35 described above moves away from the valve seat surface 113. Therefore, it is possible to avoid interference between the end section 135 described above and the valve seat surface 113 when the valve body 130 pivots.

[0051] (4) In some embodiments, in the above configuration (1), a region 113b of the valve seat surface 113, which is located on the other side described above across a centerline Cbp of the bypass channel 110, may be arranged upstream of the bypass channel 110 relative to a region 113a, which is located on the one side described above, as viewed from the direction of the axis AX described above. The axis AX, which is a center of rotation of the valve body 130, may be located on the one side described above across the centerline Cbp described above, as viewed from the direction of the axis AX described above.

[0052] Among the areas outside the bypass channel 110, in the area on the side described above, extending across the centerline Cbp of the bypass channel 110, there exists an element, such as the support arm 120 or the shaft located at the center of rotation (axis AX) of the valve body 130, which can impede the flow of the exhaust gas expelled from the outlet 111 of the bypass channel 110. However, due to design constraints or the like, it is also conceivable that there may be a case in which it is preferable to direct the exhaust gas expelled from the outlet 111 of the bypass channel 110 more towards the area on the side described above, extending across the centerline Cbp of the bypass channel 110, than towards the area on the other side described above.Even in such a case, with the above configuration (4), since the exhaust gas flowing through the bypass channel 110 and being expelled from the outlet 111 of the bypass channel 110 is guided from the other side described above via the center line Cbp of the bypass channel 110 to the one side described above, an impairment of the flow of the exhaust gas after it has been expelled from the outlet 111 of the bypass channel 110 is suppressed, which makes it possible to suppress the pressure loss.

[0053] (5) A turbine 30 according to at least one embodiment of the present disclosure includes the wastegate valve device 100 having any one of the above configurations (1) to (4).

[0054] In the above configuration (5), since the turbine 30 includes the wastegate valve device 100 which has any of the above configurations (1) to (4), it is possible to improve the control accuracy of the exhaust gas quantity in the range where the valve opening degree θv; is relatively small.

[0055] (6) A turbine according to at least one embodiment of the present disclosure comprises: the wastegate valve device 100 having the configuration (2) or (3) above; a turbine wheel 3; and an exhaust channel forming section 55 forming an exhaust channel 171 downstream of the turbine wheel 3. The exhaust channel 171 comprises: an exhaust channel main flow region 173, which is located adjacent to the bypass channel 110 on the other side described above, across the centerline Cbp of the bypass channel 110, as viewed from the direction of the axis AX described above; and a confluence region 175 in which an exhaust gas discharged from the outlet 111 of the bypass channel 110 and an exhaust gas flowing through the exhaust channel main flow region 173 merge.

[0056] With the above configuration (6), the main exhaust channel flow area 173 of the exhaust channel 171 is located adjacent to the bypass channel 110 on the other side described above, across the centerline Cbp of the bypass channel 110, as viewed from the direction of the axis AX described above. With the above configuration (6), since the turbine 30 includes the wastegate valve device 100, which has the above configuration (2) or (3), as described above, the exhaust gas flowing through the bypass channel 110 and being expelled from the outlet 111 of the bypass channel 110 is guided from the one side described above, across the centerline Cbp of the bypass channel 110, to the other side described above along the closing surface 131.Thus, the exhaust gas flowing through the bypass channel 110 and expelled from the outlet 111 of the bypass channel 110 easily merges with the exhaust gas flowing through the main flow area of ​​the exhaust channel 173 in the confluence area 175, and a disturbance of the flow of the exhaust gas flowing through the exhaust channel 171 is suppressed, which makes it possible to suppress the pressure loss of the exhaust gas in the exhaust channel 171.

[0057] (7) In some embodiments, in the above configuration (6), an angular difference Δθ between an extension direction to a downstream side of the discharge channel main flow area 173 and an extension direction of the valve seat surface 113 from the one side described above across the center line Cbp of the bypass channel 110 to the other side described above on the valve seat surface 113 is preferably less than 90 degrees, as viewed from the direction of the axis AX described above.

[0058] With the above configuration (7), the exhaust gas flowing through the bypass channel 110 and expelled from the outlet 111 of the bypass channel 110 merges more easily with the exhaust gas flowing through the main discharge channel flow area 173 in the confluence area 175 when the angle difference Δθ described above is less than 90 degrees, and disturbance of the flow of the exhaust gas flowing through the discharge channel 171 is further suppressed, which makes it possible to further suppress the pressure loss of the exhaust gas in the discharge channel 171.

[0059] (8) A turbocharger 1 according to at least one embodiment of the present disclosure includes the turbine 30 having any one of the above configurations (5) to (7).

[0060] With the above configuration (8) it is possible to improve the control accuracy of the boost pressure in turbocharger 1. Reference symbol list 1 turbocharger 3 Turbine wheel 5 Housings (turbine housings) 7 Scroll section (Scroll flow channel generation section) 30 turbines 55 Ejection channel formation section 100 Wastegate valve device 110 Bypass canal 111 Outlet 113 Valve seat surface 120 support arm 121 Rotary shaft 130 valve bodies 131 Closing area 135 Final section 150 Wastegate valve bodies 171 Ejection channel 173 Exhaust channel main flow area 175 Confluence area

Claims

[1] Wastegate valve device (100) arranged on a bypass channel (110) formed within a turbine housing (5) containing a turbine wheel (3) bypassing a turbine (30) of a turbocharger (1) arranged on an exhaust port of an engine, comprising: a valve seat surface (113) formed at an outlet (111) of the bypass channel (110); and a wastegate valve body (150) which supports a support arm (120) which is rotatably supported about an axis (AX), and a valve body (130), which is supported by the support arm (120), wherein the valve body (130) is configured to come into and out of contact with the valve seat surface (113) according to a rotation of the support arm (120), wherein the valve seat surface (113) is inclined orthogonal to an axial direction (BPAX) of the bypass channel (110) with respect to a direction of the axis (AX); wherein the bypass channel (110) connects a spiral flow channel (7a) and an exhaust channel (171) for bypassing the turbine wheel (3); and wherein a center of rotation of the valve body (130), as seen from the direction of the axis (AX), is arranged radially outside a center line (Cbp) of the bypass channel (110) and radially outside an outermost end of a spiral flow channel generating section (7) that forms the spiral flow channel (7a). [2] Wastegate valve device (100) according to claim 1, wherein in the valve seat surface (113) a region (113a) of the valve seat surface (113) is arranged, which is located on a radially outer side above the center line (Cbp) of the bypass channel (110), upstream of the bypass channel (110) relative to a region (113b) which is located on a radially inner side, as seen from the direction of the axis (AX). [3] Wastegate valve device (100) according to claim 2, wherein the center of rotation is located in a region further from the center line (Cbp) relative to a normal (N) to the valve seat surface (113) passing through an end section (135) of the valve body (130) located on one side of the valve seat surface (113) and on the radially outer side above the center line as seen from the direction of the axis (AX). [4] Wastegate valve device (100) according to claim 1, wherein in the valve seat surface (113) a region of the valve seat surface (113b) is arranged which is located on a radially inner side above the center line (Cbp) of the bypass channel (110), upstream of the bypass channel (110) relative to a region which is located on a side, seen from the direction of the axis (AX). [5] Turbine, encompassing: the wastegate valve device (100) according to claim 1. [6] Turbine, encompassing: the wastegate valve device (100) according to claim 2 or 3; a turbine wheel (3); and an exhaust channel formation section (55) which forms an exhaust channel (171) which is formed downstream of the turbine wheel (3), the ejection channel (171) comprises: an exhaust channel main flow region (173) located adjacent to the bypass channel (110) on the radially inner side above the centerline (Cbp) of the bypass channel (110), as seen from the direction of the axis (AX); and a confluence area (175) where an exhaust gas discharged from the outlet (111) of the bypass channel (110) and an exhaust gas flowing through the main discharge channel flow area (173) merge. [7] Turbine according to claim 6, wherein an angular difference (Δθ) between an extension direction to a downstream side of the main discharge channel flow area (173) and an extension direction of the valve seat surface (113) from one side across the center line (Cbp) of the bypass channel (110) to the other side on the valve seat surface (113), as seen from the direction of the axis (AX), is less than 90 degrees. [8] Turbochargers, including: the turbine according to claim 5.

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