Turbine

Abstract

A turbomachine includes: a wastegate chamber (28); a turbine housing (12) defining a turbine inlet (14), the turbine housing (12) comprising: a wastegate inlet passage (30) defining a flow path between the turbine inlet (14) and a wastegate chamber (28), where the wastegate inlet passage (30) comprises a turbine port (38) proximate the turbine inlet (14) and a non-circular valve port (36) proximate the wastegate chamber (28), and a raised perimeter (52), the raised periphery surrounds the non-circular valve port (36) and is conformal with the shape of the non-circular valve port (36), wherein the raised periphery comprises a first sealing surface (52); and a valve member (42) comprising a second sealing surface (50) wherein the valve member (42) is movable between a closed position in which the second sealing surface (50) forms a seal with the first sealing surface (54) to prevent fluid flow along the flow path and an open position in which the second sealing surface (50) is spaced from the first sealing surface (54) to allow fluid flow along the flow path.

Description

Technical Field

[0001] The present disclosure relates to turbomachines, such as those in turbochargers or other turbomachinery devices. In particular, the present disclosure relates to turbomachines with wastegates having wastegate inlet passages with non-circular valve ports. Background Art

[0002] A turbine converts the potential energy of a fluid into mechanical work. A conventional turbine includes a turbine housing that defines a turbine inlet, a turbine chamber, and a turbine outlet. A turbine impeller is mounted in the turbine chamber. The turbine inlet typically includes an annular inlet and an inlet volute, the annular inlet being defined between facing radial walls arranged around the turbine chamber, the inlet volute being arranged around the annular inlet. In use, a fluid enters the turbine through the turbine inlet, where the fluid is transferred to a turbine impeller in the turbine chamber. The fluid impacts one or more blades defined by the turbine impeller, thereby applying a force to the turbine impeller to rotate the turbine impeller. Once the fluid has passed through the turbine impeller, the fluid leaves the turbine via the turbine outlet.

[0003] A turbocharger is a well-known turbomechanical device used to supply air to the inlet of an internal combustion engine at a pressure higher than atmospheric pressure (boost pressure). A turbocharger utilizes a turbine and a compressor mounted to a common shaft to increase the pressure of atmospheric air entering the internal combustion engine. Exhaust gas from the outlet manifold of the internal combustion engine is passed through the turbine. The rotation of the turbine impeller causes the rotation of the shaft and thereby the rotation of the compressor impeller. Air is drawn in through the compressor and is compressed to the boost pressure by the compressor impeller. By providing higher pressure air to the internal combustion engine, more oxygen is available within the internal combustion engine to burn the fuel. Thus, the turbocharger allows more fuel to be burned and therefore the internal combustion engine can produce more power.

[0004] It is known to provide a turbine with a bypass device (typically referred to as a wastegate) that allows fluid to flow from the turbine inlet to the turbine outlet without passing through the turbine wheel. Typically, the wastegate is equipped with a wastegate valve (e.g., a poppet valve or a swing valve) configured to allow or prevent flow bypassing the turbine wheel.

[0005] The wastegate includes a wastegate chamber in which a wastegate valve is located. The wastegate chamber is typically at least partially defined by a turbine housing. The wastegate also includes a wastegate inlet passage extending through the turbine housing between the turbine inlet and the wastegate chamber. An end of the wastegate inlet passage near the turbine inlet is referred to herein as a turbine port, and an end of the wastegate inlet passage near the wastegate chamber is referred to herein as a valve port. The wastegate inlet passage provides a fluid flow path between the turbine inlet and the wastegate chamber. The wastegate also includes a wastegate outlet, which provides a fluid flow path between the wastegate chamber and the turbine outlet or the atmosphere.

[0006] The wastegate valve includes a valve member that can move within a wastegate chamber. For example, where the wastegate valve is a swing valve, the valve member can be mounted on an arm that can rotate about a pivot, which is mounted to the wastegate chamber and spaced apart from the wastegate valve. The wastegate is closed by moving the valve member to an advanced position, in which the valve member blocks the valve port of the wastegate inlet passage, thereby preventing gas from entering the wastegate chamber and ensuring that the gas impacts the turbine impeller. The wastegate is opened by moving the valve member away from the valve port of the wastegate inlet passage to a retracted position. This allows gas from the turbine to enter the wastegate chamber through the wastegate inlet passage between the valve member and the wall of the wastegate chamber, thereby bypassing the turbine impeller.

[0007] When a wastegate is used in a turbocharger, when the boost pressure of the fluid at the compressor outlet increases to above a predetermined level, the wastegate is opened to allow the fluid to bypass the turbine wheel. The actuator closes the wastegate by moving the wastegate valve to the forward position and maintaining the wastegate in the forward position. The actuator force required to maintain the valve member in the forward position and thus keep the wastegate closed depends on the force of the fluid in the turbine acting on the valve member at the valve port, which is balanced by the actuator force. The fluid force is proportional to the area over which the fluid acts on the valve member. The area over which the fluid acts on the valve member depends on the position of the seal formed by the valve member around the valve port. If the sealing position between the valve member and the wall of the wastegate chamber is not clearly defined, for example due to large component manufacturing tolerances, the area may be difficult to predict.

[0008] EP2489853A1 relates to a wastegate comprising a wastegate inlet passage having a circular cross section and an axis extending perpendicular to the surface of the wall of the wastegate chamber against which the valve member abuts for sealing, so that the wastegate has a circular valve port. The valve member takes the form of a disc. It discloses that the valve member or the wall of the wastegate chamber surrounding the circular valve port may include a raised annular rim, which defines a sealing surface. The sealing surface is intended to reduce the incidence of fluid leakage from the bypass channel between the valve member and the wall of the wastegate chamber. When the wastegate is closed, fluid leakage from the bypass channel into the wastegate chamber may have an adverse effect on the performance and / or efficiency of the turbine and / or turbocharger. Summary of the invention

[0009] An object of the present disclosure is to provide an improved wastegate having a non-circular valve port, which may, for example, provide greater flexibility in packaging, simpler equipment, improved efficiency, better accuracy in adjustment or operation, etc.

[0010] According to a first aspect, a turbine is provided, the turbine comprising a wastegate chamber. The turbine further comprises a turbine housing. The turbine housing defines a turbine inlet. The turbine housing comprises a wastegate inlet passage. The wastegate inlet passage defines a flow path between the turbine inlet and the wastegate chamber. The wastegate inlet passage comprises a turbine port proximate the turbine inlet and a non-circular valve port proximate the wastegate chamber. The turbine housing further comprises a raised periphery, the raised periphery surrounding the non-circular valve port and conforming to the shape of the non-circular valve port. The raised periphery comprises a first sealing surface. The turbine further comprises a valve member. The valve member comprises a second sealing surface. The valve member is movable between a closed position and an open position, in which the second sealing surface forms a seal with the first sealing surface to prevent fluid from flowing along the flow path, and in which the second sealing surface is spaced apart from the first sealing surface to allow fluid to flow along the flow path.

[0011] Non-circular valve ports may allow for greater flexibility in packaging of the wastegate and packaging of the turbine, thereby broadening machining options.

[0012] Beneficially, the first sealing surface of the raised periphery can provide a controlled sealing position between the valve member and the turbine housing. This can allow the area of ​​the valve member to be accurately predicted when the valve member is in the closed position by the fluid pressure from the valve port, so that the actuator controlling the wastegate can be adjusted more accurately to move the valve member between the closed position and the open position at the appropriate time. In addition, having a controlled contact area between the valve member and the housing via the raised periphery can provide an improved seal. When the valve member is in the closed position, the improved seal will result in improved turbine efficiency.

[0013] The non-circular valve port may have a major dimension defined by a maximum distance between opposing points on the valve port. The second sealing surface may have a minor dimension defined by a minimum distance between opposing points on an outer edge of the second sealing surface. The minor dimension of the second sealing surface may be greater than the major dimension of the non-circular valve port.

[0014] The small size of the second sealing surface is larger than the large size of the non-circular valve port, so that the second sealing surface on the valve member forms a seal with the first sealing surface on the raised periphery, which can allow the valve member to be manufactured with a larger tolerance without affecting the function of the wastegate or the efficiency of the turbine. As long as the small size of the second sealing surface is larger than the large size of the non-circular valve port, the second sealing surface can form a seal with the first sealing surface regardless of how large the small size of the second sealing surface is compared to the small size of the non-circular valve port. In addition, the relative size of the valve port and the valve member can allow a simple wastegate device without the need for an anti-rotation feature to prevent the valve member from rotating relative to the raised periphery. When the first sealing surface contacts the second sealing surface, a seal can be formed regardless of the orientation of the valve member relative to the raised periphery. The second sealing surface can define a valve axis passing through the center of the second sealing surface, and the valve member can rotate freely around the valve axis. Allowing the valve member to rotate freely can reduce uneven wear on the sealing surface of the valve member.

[0015] The non-circular valve port may define a plane.The wastegate inlet passage may extend along a passage axis that is at an oblique angle to the plane of the non-circular valve port.

[0016] Advantageously, a favorable angle of the flow path through the wastegate inlet passage relative to the turbine inlet can be achieved, thereby improving the emission coefficient of the wastegate and the operation of the turbine and / or turbocharger. In addition, the oblique angle of the wastegate inlet passage relative to the valve port allows greater flexibility in the packaging of the wastegate and turbine, thereby widening the machining options.

[0017] The major dimension of the non-circular valve port may be at least 15 mm. The major dimension of the non-circular valve port may be up to 40 mm.

[0018] The wastegate inlet passage may have a non-circular axial cross-section, ie an oval, teardrop, pear, square or irregular shape. Alternatively, the wastegate inlet passage may have a circular axial cross-section.

[0019] The shape of the non-circular valve port may be the same shape as the axial cross-section of the wastegate inlet passage, wherein the passage axis is perpendicular to the plane of the valve port. Alternatively, the shape of the non-circular valve port may be different from the shape of the axial cross-section of the wastegate inlet passage, wherein the passage axis is at an oblique angle to the plane of the valve port.

[0020] The non-circular valve port may be oval, teardrop, pear, square or irregular in shape. The shape of the valve port may be configured to optimize gas flow through the valve port when the valve member is in the open position. The shape of the valve port may be configured to allow for alternative packaging arrangements of the wastegate.

[0021] When the valve port has an elliptical shape, the elliptical valve port may be defined by a major diameter and a minor diameter. The major dimension of the elliptical valve port may be the major diameter. The first sealing surface may have an elliptical ring form.

[0022] The first sealing surface may have a constant width. The major dimension of the first sealing surface may be equal to the major dimension of the valve port plus twice the width of the first sealing surface. The width of the sealing surface may be between 1 mm and 5 mm. Beneficially, the sealing surface is made to be an optimal width that is large enough to adequately withstand the environment within the turbine and the hot gases that may pass through the wastegate, and that is small enough to provide an accurate sealing position so that the gas force acting on the valve member in the closed position can be accurately estimated and the wastegate actuator can be accurately adjusted. In addition, minimizing the width of the ground reduces the amount of free space around the valve port that is required to provide sight and access during machining.

[0023] The second sealing surface may be circular.The minor dimension of the second sealing surface may be the diameter of the second sealing surface.

[0024] Advantageously, a standard valve can be used. In addition, the valve member can be manufactured with greater tolerances without affecting the function of the wastegate or the efficiency of the turbine.

[0025] The first sealing surface may have a major dimension defined by a maximum distance between opposing points on an outer edge of the first sealing surface.The minor dimension of the second sealing surface may be greater than the major dimension of the first sealing surface.

[0026] When the valve port is elliptical, the raised periphery may be in the form of an elliptical ring, and the outer edge of the ellipse of the first sealing surface may be defined by a major diameter and a minor diameter. The major dimension of the outer edge of the ellipse of the first sealing surface may be its major diameter. In the case where the first sealing surface has a constant width, the major dimension of the first sealing surface may be equal to the major dimension of the valve port plus twice the width of the first sealing surface.

[0027] The first sealing surface may be coplanar with the valve port.

[0028] The first sealing surface may be tapered away from the valve port. The first sealing surface may be inclined or angled relative to the plane of the valve port. The first sealing surface may be inclined or angled away from the valve port. The first sealing surface may take the form of a shallow truncated cone. When the valve member is in the closed position, a portion of the first sealing surface near the inner edge of the first sealing surface may be sealingly engaged with the second sealing surface. When the valve member is in the closed position, the inner edge of the first sealing surface may be embedded in the second sealing surface. Beneficially, the tapered sealing surface controls the sealing position (near the inner edge of the first sealing surface) formed between the first sealing surface and the second sealing surface. Controlling the sealing position allows the area of ​​the valve member to be accurately calculated by the valve port fluid pressure, so that the wastegate actuator can be accurately adjusted to improve the efficiency of the wastegate and / or prevent leakage through the wastegate that may reduce the efficiency of the turbine.

[0029] The first sealing surface may be flat or concave.

[0030] The raised rim may be formed in the turbine housing by interpolation milling. The wastegate inlet passage may be formed in the turbine housing by interpolation milling.

[0031] Advantageously, manufacturing by interpolation milling allows the valve port and the raised rim to have close tolerances. The close tolerance valve port and raised rim allow accurate calculation of the area on the valve member to which the valve port fluid pressure is applied, so that the wastegate actuator can be accurately adjusted to improve the efficiency of the wastegate and / or prevent leakage through the wastegate that may reduce turbine efficiency.

[0032] The wastegate inlet passage may be formed in the turbine housing by 5-axis milling. The raised rim may be formed in the turbine housing by 5-axis milling. Beneficially, manufacturing by 5-axis milling allows the first sealing surface to be formed as a shallow frustoconical shape and / or the wastegate inlet passage to be formed along an axis that is not coaxial with the raised rim.

[0033] According to a second aspect, there is provided a turbocharger comprising the turbine of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

[0035] Figure 1 is a schematic cross-sectional view of a turbine and a wastegate according to an embodiment of the present invention;

[0036] Figure 2 yes Figure 1 A schematic cross-sectional view of a wastegate inlet passage and valve member of a wastegate;

[0037] Figure 3 yes Figure 1 A plan view of a wastegate inlet passage and a valve member of a wastegate;

[0038] Figure 4a yes Figure 1 A perspective cutaway view of a turbine and a wastegate valve of FIG. 1 , wherein the wastegate valve is in a closed configuration;

[0039] Figure 4b yes Figure 1 a perspective cutaway view of a wastegate inlet passage and valve member of a wastegate, wherein the wastegate valve is in an open configuration;

[0040] Figure 5 is a cutaway perspective view of a turbocharger including a wastegate according to the present invention;

[0041] Figure 6 is a schematic cross-sectional view of an actuator for controlling a wastegate according to the present invention;

[0042] Figure 7a is a cross-sectional view of a turbine and a wastegate according to another embodiment of the present invention;

[0043] Figure 7b yes Figure 7a A front view of a wastegate inlet passage;

[0044] Figure 7c yes Figure 7a Detailed view of the raised periphery of the;

[0045] Figure 8a is a cross-sectional view of a turbine and a wastegate according to another embodiment of the present invention;

[0046] Figure 8b yes Figure 8a A front view of a wastegate inlet passage;

[0047] Figure 8c yes Figure 8a Detailed view of the raised periphery of the;

[0048] Figure 9a is a cross-sectional view of a turbine and a wastegate according to another embodiment of the present invention;

[0049] Figure 9b yes Figure 9a A front view of a wastegate inlet passage; and

[0050] Fig.9c yes Figure 9a Detailed view of the raised perimeter of the . DETAILED DESCRIPTION

[0051] refer to Figure 1 The turbine 10 includes a turbine housing 12 defining a turbine inlet 14, a turbine chamber 16, and a turbine outlet 18. The turbine also includes a turbine impeller 20 disposed in the turbine chamber 16 and capable of rotating about a turbine axis a on a shaft 24. t In use, a conventional flow path A is provided through the turbine. The fluid flows into the turbine 10 via the turbine inlet 14 and impacts the turbine wheel 20, causing the turbine wheel 20 to rotate about the turbine axis a t The fluid is redirected by the turbine wheel 20 to exit the turbine 10 via the turbine outlet 18 .

[0052] In order to regulate the volume of fluid impinging on the turbine wheel 20 , and thereby control the rotational speed of the turbine wheel 20 , the turbine is provided with a wastegate 26 which defines a bypass flow path B. The wastegate 26 provides a method of controlling the speed of the turbine wheel 20 by selectively diverting an amount of exhaust gas away from the turbine wheel 20 .

[0053] The wastegate 26 includes a wastegate chamber 28 having a chamber inlet 30 and a chamber outlet 32. The chamber inlet 30 provides a flow path between the turbine inlet 14 and the wastegate chamber 28. The chamber outlet 32 ​​provides a flow path between the wastegate chamber 28 and the turbine outlet 18. Fluid flowing along the bypass flow path B flows from the turbine inlet 14, through the chamber inlet 30 to the wastegate chamber, and through the chamber outlet 32 ​​to the turbine outlet 18. In other embodiments, the chamber outlet may provide a flow path between the wastegate chamber and the atmosphere, and the bypass flow path may terminate at the atmosphere rather than at the turbine outlet.

[0054] The wastegate 26 also includes a wastegate valve 34. The wastegate valve 34 includes a shaft 40 and an arm 44 (see Figure 2 ) is connected to a valve member 42 of the shaft 40. The valve member 42 is mounted to the arm via a pin 46. The wastegate valve 34 has a valve axis a v , the valve axis a v The valve member 42 extends through the center of the pin 46. The valve member 42 can freely move about the valve axis a vRotation. Enabling the valve member 42 to rotate freely may reduce uneven wear on the valve member 42.

[0055] The wastegate valve 34 has an open configuration and a closed configuration to control the flow of fluid along the bypass flow path B. The wastegate valve 34 can be moved between the open configuration and the closed configuration by an actuator 35. A shaft 40 is connected to the actuator 35, and the actuator 35 controls the wastegate valve 34 between the open configuration and the closed configuration through the shaft. In particular, the shaft 40 can be rotated by the actuator 35 to move the valve member 42 in the closed position (see Figure 4a ) and the open position (see Figure 4b ), in which the valve member 42 blocks the chamber inlet 30 to prevent the fluid from flowing along the bypass flow path B, and in which the valve member 42 is spaced apart from the chamber inlet to allow the fluid to flow along the bypass flow path B.

[0056] Figure 2 The chamber inlet 30 and the wastegate valve 34 are shown in more detail. The chamber inlet 30 is a passage formed in the turbine housing 12 and is referred to herein as a wastegate inlet passage. The wastegate inlet passage 30 has a passage axis a p The wastegate inlet passage is along the channel axis a p Extending through the turbine housing between the valve port 36 near the wastegate chamber 28 and the turbine port 38 near the turbine inlet 14. The turbine housing 12 includes a raised rim 52 surrounding the valve port 36. The raised rim 52 and the wastegate inlet passage 30 are formed in the turbine housing 12 by interpolation milling (other types of machining may be used to form the raised rim). The raised rim 52 is conformal to the valve port 36. Thus, the inner surface of the raised rim 52 provides a small extension of the wastegate inlet passage 30. The raised rim 52 defines a sealing surface 54, which is the first sealing surface of the wastegate 26. The sealing surface 54 of the raised rim 52 is flat. The sealing surface 54 of the raised rim 52 is coplanar with the valve port 36. The sealing surface 54 is defined between an outer edge 56 and an inner edge 58. The inner edge 58 corresponds to the valve port 36. The valve member 50 also includes a sealing surface 50, which is a second sealing surface of the wastegate 26. The sealing surface 50 of the valve member 50 is flat. Figure 4a and Figure 4b Described in more detail, the sealing surface 50 of the valve member 42 can sealingly engage with the sealing surface 54 of the raised peripheral edge 52 to block the flow of fluid along the bypass flow path B.

[0057] Continue to refer Figure 2The sealing surface 54 of the raised rim 52, the valve port 36 and the turbine port 38 define parallel planes. p Angled with respect to the plane of the sealing surface 54, the plane of the valve port 36, and the plane of the turbine port 38. Angling or canting the wastegate inlet passage 30 allows for flexibility in the packaging arrangement of the turbine 10 and the wastegate 26. Angling or canting the wastegate inlet passage 30 relative to the plane of the turbine port 38 can also provide a preferential flow angle for fluid flowing from the turbine inlet 14 along the bypass flow path B.

[0058] The wastegate inlet passage 30 is transverse to the channel axis a. p When cut, it has a circular cross section. Figure 3 As can be seen, the valve port 36 is elliptical in shape because the wastegate inlet passage 30 has a circular axial cross-section and extends along an axis that is obliquely angled relative to the plane of the valve port 36. The valve port 36 is defined by a major dimension, which in the depicted example is a major port diameter d of the elliptical valve port 36, and a minor dimension. p1 , the minor dimension being the minor port diameter d of the oval valve port 36 in the depicted example. p2 The sealing surface 54 of the raised rim 52 has an elliptical annular form. The outer edge 56 and the inner edge 58 are elliptical. The sealing surface 54 of the raised rim is defined by a width W between the inner edge 58 and the outer edge 56. The width W of the sealing surface 54 is constant. The width W of the sealing surface 54 is relative to the large port diameter d p1 and small port diameter d p2 Smaller. The width W of the sealing surface 54 can be between 1 mm and 5 mm. Preferably, for example in the present embodiment, the width W of the sealing surface 54 is between 1 mm and 3 mm. The preferred width W of the sealing surface 54 provides an optimal width that is large enough to adequately withstand the environment within the turbine and the hot gases that may pass through the wastegate, and small enough to provide an accurate sealing position, as will be discussed in more detail below. In addition, minimizing the width of the ground reduces the amount of free space around the valve port, which is required to provide sight and access during machining. The outer edge 56 of the sealing surface 54 is defined by a major dimension and a minor dimension, the major dimension being the major diameter d of the elliptical outer edge 56 in the depicted example. s1 , which in the depicted example is the minor diameter d of the outer edge 56 of the ellipse. s2 , where d s1 = d p1 +2W, and d s2 = d p2 +2W.

[0059] Combined with reference Figure 2 and Figure 3 , the valve member 42 is in the form of a disc and has a circular sealing surface 50. In other embodiments, the sealing surface of the valve member may be non-circular. In other embodiments, the sealing surface of the valve member may have the same shape as the valve port. In the case where the sealing surface of the valve member is non-circular, rotation of the valve member about the valve axis may be prevented by an anti-rotation feature (e.g., an anti-rotation pin, etc.), thereby ensuring that the non-circular sealing surface of the valve member maintains the correct orientation relative to the non-circular valve port. The valve sealing surface 50 is defined by a minor dimension, which in the depicted example is the diameter D of the circular sealing surface. The diameter D is equal to or greater than the major diameter d of the valve port. p1 Preferably, as in the present embodiment, the diameter D is also equal to or greater than the major diameter d of the outer edge 56 of the sealing surface 54 defined by the raised periphery 52. s1 In other embodiments, the valve member may have a non-circular sealing surface, in which case the minor dimension is the minimum distance between opposing points on the outer edge of the sealing surface. The minor dimension is equal to or greater than the major dimension of the valve port. Preferably, the minor dimension is also equal to or greater than the major dimension of the outer edge of the sealing surface defined by the raised periphery. The relative dimensions of the sealing surface 50 of the valve member 42 and at least the valve port 36 ensure that the valve member 42 is able to fully cover the valve port 36 regardless of the position of the valve member 42 about the valve axis a. v This is true regardless of the rotational position of the valve member 52 and even though the valve port 36 has a planar shape that is different from the shape of the sealing surface 50 of the valve member 52.

[0060] Figure 4a and Figure 4b The wastegate valve 34 is shown in a closed configuration and an open configuration, respectively. When the wastegate valve 34 is in the closed configuration, as shown in FIG. Figure 4a As shown, the valve member 42 is in the closed position. The valve member 42 abuts the raised peripheral edge 52 in its closed position. The center of the sealing surface 50 of the valve member 42 is substantially aligned with the center of the valve port 36, that is, the valve axis a is aligned with the valve port 36. v The point of intersection with the sealing surface 50 of the valve member 42 and the channel axis a p The sealing surfaces 50, 54 are sealingly engaged to prevent fluid from flowing through the valve port 36, so that fluid cannot flow from the wastegate inlet passage 30 to the wastegate chamber 28, and the bypass flow path B of the fluid is blocked. When the wastegate valve 34 is in the open configuration, as shown in FIG. Figure 4b4, the valve member 42 is shown in the open position. When the valve member 42 is in the open position, the sealing surface 50 of the valve member 42 is spaced apart from the sealing surface 54 of the raised rim 52. Fluid flow from the wastegate inlet passage 30 through the valve port 36 to the wastegate chamber 28 is not impeded. Instead, fluid flow from the wastegate inlet passage 30 to the wastegate chamber 28 is permitted between the raised rim 52 and the valve member 42. Thus, fluid flow along the bypass flow path of the fluid is permitted.

[0061] The actuation axis a of the shaft 40 passes through the center of the shaft 40. a The wastegate valve 34 moves from the closed configuration to the open configuration and the valve member moves from the closed position to the open position. The pivoting of the shaft 40 causes the arm 44 to move about the actuation axis a a Rotation, and therefore also the valve member 42, about the actuation axis a a Rotation. The valve member 42 moves through a rotation angle sufficient to provide clearance between the sealing surface 50 of the valve member 42 and the sealing surface 54 of the raised rim 52. This type of valve is known as a swing valve. In other embodiments, other types of valves, such as a poppet valve, may be used.

[0062] Figure 5 The wastegate 26 implemented in the turbocharger 60 is shown. The turbocharger 60 includes a turbine 100, which substantially corresponds to the previously described turbine 10, except that the turbine inlet 114 includes a double volute 115. In other embodiments, the turbocharger may include the turbine 10. The double volute 115 includes a first passage 115a and a second passage 115b, both of which are in fluid communication with the turbine impeller 120. The bypass flow path B extends from the first passage 115a of the double volute to the turbine outlet 118. The turbocharger 60 also includes a compressor 62 and a bearing arrangement 64. The compressor 62 includes a compressor housing 66, which defines a compressor inlet 68, a compressor chamber 70, a compressor volute 78, and a compressor outlet 72. Within the compressor chamber 70 is a compressor impeller 74. The compressor impeller 74 is mounted on a shaft 124, and the turbine impeller 120 is also mounted on the shaft 124, so that the compressor impeller 74 and the turbine impeller 120 rotate together. The bearing arrangement 64 includes a bearing 76 located in a bearing housing 77. The bearing 76 supports the shaft 124 between the compressor impeller 74 and the turbine impeller 20. The bearing housing 77 is coupled between the turbine housing 112 and the compressor housing 66.

[0063] Exhaust gas from an internal combustion engine (not shown) is delivered to the turbine 100. The exhaust gas enters a turbine inlet 114 defined by a turbine housing 112. The exhaust gas strikes a turbine wheel 120, which causes the turbine wheel 120 to rotate about a turbine axis a. t Rotation. Rotation of the turbine wheel 120 drives rotation of the shaft 124 and, therefore, the compressor wheel 74 .

[0064] The rotation of the compressor impeller 74 causes air from the atmosphere to be drawn into the compressor inlet 68. The air passes over the compressor impeller 74 and enters a compressor volute 78 defined by the compressor housing 66. Because the compressor impeller 74 imparts kinetic energy to the incoming air, the air in the compressor volute 78 is at a higher pressure than the air entering the compressor inlet 68. The compressed air exits the compressor 62 via the compressor outlet 72 where it is delivered to the intake manifold of an internal combustion engine (not shown).

[0065] The wastegate 26 reduces the amount of exhaust gas that strikes the turbine wheel 20 by providing a bypass flow path B from the turbine inlet 114 to the turbine outlet 118, and thereby regulates the rotation of the turbine wheel 120. When the wastegate 26 is used in the turbocharger 60, control of the rotation of the turbine wheel 20 translates into control of the boost pressure of the compressed air leaving the compressor 62. This provides benefits in preventing adverse flow conditions (e.g., compressor surge) from occurring in the compressor.

[0066] The wastegate according to an embodiment of the present invention can be actuated by various devices, including hydraulic actuators or electric actuators. The turbocharger 60 includes a pneumatic actuator 35. The actuator 35 provides control of the wastegate 26 according to the boost pressure of the compressed air delivered by the compressor 62. The actuator 35 includes a control device 37 and an operating arm 79. The first end of the operating arm 79 is connected to the control device 37 so that the control device 37 can control the bidirectional axial movement of the operating arm 79. The second end of the operating arm 79 is connected to the shaft 40 of the wastegate 26 via a connecting rod 41. The connecting rod 41 converts the axial movement of the operating arm 79 into the rotation of the shaft 40. The axial movement of the operating arm 79 in a first direction causes the rotation of the shaft 40, thereby moving the valve member 42 from the closed position to the open position. The axial movement of the operating arm 79 in a second direction opposite to the first direction causes the rotation of the shaft 40, thereby moving the valve member 42 from the open position to the closed position. Other connecting rod devices and other actuating devices can be used.

[0067] refer to Figure 5 and Figure 6, the control device 37 includes a biasing member 80 (i.e., a spring) and a diaphragm 82, the biasing member 80 biasing the operating arm 79 in the second direction to maintain the valve member 42 in the closed position, the diaphragm 82 being exposed to the boost pressure of the compressed air leaving the compressor 62 through the pressure signal tube 81. When the combination of the boost pressure acting on the diaphragm 82 and the pressure of the exhaust gas in the wastegate inlet passage 30 acting on the valve member 42 in the closed position overcomes the bias of the spring 80, the operating arm 79 moves in the first direction to move the valve member 42 to the open position.

[0068] When adjusting the actuator 35 before assembling the actuator 35 with the turbine, air is applied to the diaphragm 82 to move the valve member 42 away from the valve port 36 to the open position, and the pressure of the exhaust gas in the wastegate inlet passage 30 acting on the valve member 42 is assumed based on the nominal geometry of the turbine and the wastegate in order to determine the appropriate spring force required. Therefore, in order to adjust the actuator 35 to open at a predetermined boost pressure acting on the diaphragm 82, the pressure of the exhaust gas in the wastegate inlet passage 30 acting on the valve member 42 should be predicted. The pressure of the exhaust gas in the wastegate inlet passage 30 acting on the valve member 42 directly corresponds to the effective area of ​​the valve member 42 acted by the exhaust gas. The effective area of ​​the valve member 42 acted by the exhaust gas depends on the location where the seal is formed between the sealing surface 50 of the valve member 42 and the sealing surface 54 of the raised peripheral edge 52. The sealing position can be any position between the inner edge 58 and the outer edge 56 of the sealing surface 54 of the raised rim 52 where the sealing surface 50 of the valve member 42 contacts the sealing surface 54 of the raised rim 52. The effective area includes a known portion (which is the area of ​​the valve port 36) plus an unknown portion (which is the undetermined area of ​​the sealing surface 54 of the raised rim 52 that contacts the sealing surface 50 of the valve member 42 depending on the sealing position). The width W of the sealing surface 54 of the raised rim 52 relative to the major diameter d of the valve port 36 is p1 and the minor diameter d p2 The unknown portion of the effective area is smaller than the known portion of the effective area, for example, the unknown portion of the effective area may be 10% of the known portion of the effective area. Therefore, the uncertainty and margin of error in predicting the effective area and thereby the pressure of the exhaust gas in the wastegate inlet passage 30 acting on the valve member 42 may be reduced by controlling the geometry of the port and the sealing surface so that the actuator 35 may be adjusted with greater accuracy. In addition, product-to-product variation is reduced. By accurately adjusting the actuator 35, the risk of the wastegate valve moving between the open and closed configurations at inappropriate times is reduced, and the associated adverse effects on turbocharger performance are mitigated.

[0069] Figure 7a , Figure 7b and Figure 7c An alternative turbine 210 is shown which is provided with a wastegate 226. Apart from the features to be described, the turbine 210 and the wastegate 226 correspond substantially to the turbine 10 and the wastegate 26. Like features are provided with like reference numerals increased by 200.

[0070] The turbine 210 includes a turbine housing 212 defining a turbine inlet 214. In use, a conventional flow path through the turbine is provided. Fluid flows into the turbine 210 via the turbine inlet 214 and impacts the turbine wheel, thereby causing the turbine wheel to rotate. The fluid is redirected by the turbine wheel to flow out of the turbine 210 via the turbine outlet. In order to regulate the volume of fluid impacting the turbine wheel, and thereby control the rotational speed of the turbine wheel, the turbine is provided with a wastegate 226, which defines a bypass flow path and selectively diverts exhaust gas away from the turbine wheel. The wastegate 226 includes a wastegate chamber 228 having a chamber inlet 230 and a chamber outlet. The wastegate 226 also includes a wastegate valve 234 (which has been described herein for clarity). Figure 7b The wastegate valve 234 is removed). The wastegate valve 234 has an open configuration and a closed configuration to control the flow of fluid along the bypass flow path.

[0071] The chamber inlet 230 is a passage formed in the turbine housing 212, referred to herein as a wastegate inlet passage. The wastegate inlet passage 230 extends through the turbine housing 212 between a valve port 236 near the wastegate chamber 228 and a turbine port 238 near the turbine inlet 214. The turbine housing 212 includes a raised rim 252 surrounding the valve port 236. The raised rim 252 conforms to the valve port 236, so that the inner surface of the raised rim 252 provides an extension of the wastegate inlet passage 230. The raised rim 252 defines a sealing surface 254, which is a first sealing surface of the wastegate 226. The sealing surface 254 is defined between an outer edge 256 and an inner edge 258. The inner edge 258 corresponds to the valve port 236.

[0072] The wastegate valve 234 includes a sealing surface 250, which is a second sealing surface of the wastegate 226. The sealing surface 250 of the valve member 242 is flat. The sealing surface 250 of the valve member 242 can be sealingly engaged with the sealing surface 254 of the raised rim 252 to block the flow of fluid along the bypass flow path. The sealing surface 254 of the raised rim 252 is tapered away from the valve port 236, so that a portion of the sealing surface 254 of the raised rim 252 near the inner edge 258 of the sealing surface 254 forms a seal with the sealing surface 250 of the valve member 242. Beneficially, the geometry of the sealing surface 254 of the control raised rim 252 is tapered to provide a seal between the sealing surfaces 250, 254 near the inner edge 258 of the sealing surface 254, increasing the certainty in estimating the seal position and thus reducing the error in estimating the effective area of ​​the valve member 242 loaded by the exhaust gas, thereby allowing for more accurate adjustment of the actuator. The taper angle of the sealing surface 250 relative to the plane of the valve port 236 can be between 1° and 10°. In this embodiment, the taper angle is 5°. In an alternative embodiment, the taper angle can preferably be 2.5°. The preferred taper angle ensures that the raised rim is strong enough to withstand the environment within the wastegate and any hot gases that may pass through the valve port.

[0073] The wastegate inlet passage 230 extends along an axis that is oblique to the plane of the valve port 236 and the plane of the turbine port 238. The wastegate inlet passage 230 has a circular cross section when taken transversely to the axis of the passage 230. Since the wastegate inlet passage 230 has a circular axial cross section and extends along an axis that is oblique to the plane of the valve port 236, the valve port 236 is elliptical in shape. The sealing surface 254 of the raised periphery 252 has an elliptical annular form. The outer edge 256 and the inner edge 258 are elliptical. The sealing surface 254 of the raised periphery is defined by the width between the inner edge 258 and the outer edge 256. The width of the sealing surface 254 is constant. The width of the sealing surface 54 can be between 1 mm and 5 mm. Preferably, for example in the present embodiment, the width of the sealing surface 254 is between 3 mm and 5 mm. The preferred width W of the sealing surface 254 provides an optimal width that is large enough to adequately withstand the environment within the turbine and the hot gases that may pass through the wastegate, and small enough to provide an accurate sealing position so that the gas forces acting on the valve member in the closed position can be accurately estimated and the wastegate actuator can be accurately adjusted.

[0074] Figure 8a , Figure 8b and Figure 8cAn alternative turbine 310 is shown which is provided with a wastegate 326. Apart from the features to be described, the turbine 310 and the wastegate 326 correspond substantially to the turbine 10 and the wastegate 26. Like features are provided with like reference numerals increased by 300.

[0075] The turbine 310 includes a turbine housing 312 defining a turbine inlet 314. In use, a conventional flow path through the turbine is provided. The fluid flows into the turbine 310 via the turbine inlet 314 and impacts the turbine wheel, thereby rotating the turbine wheel. The fluid is redirected by the turbine wheel to flow out of the turbine 310 via the turbine outlet. In order to adjust the volume of the fluid impacting the turbine wheel and thereby control the rotational speed of the turbine wheel, the turbine is provided with a wastegate 326, which defines a bypass flow path and selectively diverts exhaust gas away from the turbine wheel. The wastegate 326 includes a wastegate chamber 328 having a chamber inlet 330 and a chamber outlet. The wastegate 326 also includes a wastegate valve 334. The wastegate valve 334 has an open configuration and a closed configuration to control the flow of fluid along the bypass flow path.

[0076] The chamber inlet 330 is a passage formed in the turbine housing 312, referred to herein as a wastegate inlet passage. The wastegate inlet passage 330 extends through the turbine housing 312 between a valve port 336 near the wastegate chamber 328 and a turbine port 338 near the turbine inlet 314. The turbine housing 312 includes a raised rim 352 surrounding the valve port 336. The raised rim 352 conforms to the valve port 336, so that the inner surface of the raised rim 352 provides an extension of the wastegate inlet passage 330. The raised rim 352 defines a sealing surface 354, which is a first sealing surface of the wastegate 326. The sealing surface 354 is defined between an outer edge 356 and an inner edge 358. The inner edge 358 corresponds to the valve port 336.

[0077] The valve port 336 is defined by a major dimension. The wastegate inlet passage 330 extends along an axis that is oblique to the plane of the valve port 336 and the plane of the turbine port 338. The wastegate inlet passage 330 has a non-circular cross-section, so the valve port 336 (and the inner edge 358 of the sealing surface 354) is non-circular and non-elliptical. The major dimension of the valve port 336 is the maximum distance between opposite points on the valve port 336. The outer edge 356 of the sealing surface 354 is circular. The sealing surface 354 of the raised periphery is defined by the width between the inner edge 358 and the outer edge 356. The width of the sealing surface 354 can be between 1 mm and 5 mm. Preferably, for example, in the present embodiment, the width of the sealing surface 354 can be between 3 mm and 5 mm. The outer edge 356 of the sealing surface 354 is defined by a major dimension, which in the depicted example is the diameter of the circular outer edge 356.

[0078] The valve member 342 also includes a sealing surface 350, which is a second sealing surface of the wastegate 326. The valve sealing surface 350 is defined by a minor dimension, which in the depicted example is the diameter of the circular sealing surface 350. This diameter is equal to or greater than the major dimension of the valve port. Preferably, as in the present embodiment, this diameter is also equal to or greater than the major diameter of the outer edge 356 of the sealing surface 354 defined by the raised rim 352. The sealing surface 350 of the valve member 342 is flat. The sealing surface 350 of the valve member 342 and the sealing surface 354 of the raised rim 352 can be sealingly engaged to block the flow of fluid along the bypass flow path. The sealing surface 354 of the raised rim 352 is tapered away from the valve port 336, so that the portion of the sealing surface 354 of the raised rim 352 close to the inner edge 358 of the sealing surface 354 forms a seal with the sealing surface 350 of the valve member 342. The taper angle of the sealing surface 354 relative to the plane of the valve port 336 may be between 1° and 10°. In this embodiment, the taper angle is 5°. In an alternative embodiment, the taper angle may preferably be 2.5°.

[0079] Figure 9a , Figure 9b and Fig.9c An alternative turbine 410 is shown which is provided with a wastegate 426. Apart from the features to be described, the turbine 410 and the wastegate 426 correspond substantially to the turbine 10 and the wastegate 26. Like features are provided with like reference numerals increased by 400.

[0080] The turbine 410 includes a turbine housing 412 defining a turbine inlet 414. In use, a conventional flow path through the turbine is provided. The fluid flows into the turbine 410 via the turbine inlet 414 and impacts the turbine wheel, thereby rotating the turbine wheel. The fluid is redirected by the turbine wheel to flow out of the turbine 410 via the turbine outlet. In order to adjust the volume of the fluid impacting the turbine wheel and thereby control the rotational speed of the turbine wheel, the turbine is provided with a wastegate 426, which defines a bypass flow path and selectively diverts exhaust gas away from the turbine wheel. The wastegate 426 includes a wastegate chamber 428 having a chamber inlet 430 and a chamber outlet. The wastegate 426 also includes a wastegate valve 434. The wastegate valve 434 has an open configuration and a closed configuration to control the flow of fluid along the bypass flow path.

[0081] The chamber inlet 430 is a passage formed in the turbine housing 412, referred to herein as a wastegate inlet passage. The wastegate inlet passage 430 extends through the turbine housing 412 between a valve port 436 near the wastegate chamber 428 and a turbine port 438 near the turbine inlet 414. The turbine housing 412 includes a raised rim 452 surrounding the valve port 436. The raised rim 452 conforms to the valve port 436, so that the inner surface of the raised rim 452 provides an extension of the wastegate inlet passage 430. The raised rim 452 defines a sealing surface 454, which is a first sealing surface of the wastegate 426. The sealing surface 454 is defined between an outer edge 456 and an inner edge 458. The inner edge 458 corresponds to the valve port 436.

[0082] The valve port 436 is defined by a major dimension. The wastegate inlet passage 430 extends along an axis that is obliquely angled relative to the plane of the valve port 436 and the plane of the turbine port 438. The wastegate inlet passage 430 has a non-circular cross-section, so the valve port 436 is non-circular and non-elliptical. The major dimension of the valve port 436 is the maximum distance between opposing points on the valve port 436.

[0083] The raised perimeter sealing surface 454 is defined by a width between an inner edge 458 and an outer edge 456. The width of the sealing surface 454 is constant. The outer edge 456 of the sealing surface 454 is defined by a major dimension, which is the maximum distance between opposing points on the sealing surface 454. Since the width of the sealing surface 454 is constant, the major dimension of the sealing surface 454 is the major dimension of the valve port 436 plus two widths.

[0084] The valve member 442 also includes a sealing surface 450, which is a second sealing surface of the wastegate 426. The valve sealing surface 450 is defined by a minor dimension, which in the depicted example is the diameter of the circular sealing surface. This diameter is equal to or greater than the major dimension of the valve port 436. Preferably, as in the present embodiment, this diameter is also equal to or greater than the major diameter of the outer edge 456 of the sealing surface 454 defined by the raised perimeter 452.

[0085] The sealing surface 454 of the raised periphery 452 is rounded or filleted. In particular, the sealing surface 454 of the raised periphery 452 is concave. The concave sealing surface 450 has a radius of 6 mm. The sealing surface 450 of the valve member 442 and the sealing surface 454 of the raised periphery 452 can be sealed to block the fluid from flowing along the bypass flow path. The inner edge 458 of the sealing surface 450 of the raised periphery 452 is closer to the valve member than the outer edge 456, so the inner edge 458 of the sealing surface 454 of the raised periphery 452 forms a seal with the sealing surface 450 of the valve member 442. Beneficially, controlling the geometry of the sealing surface 454 in this way increases the certainty in estimating the sealing position, and therefore reduces the error in estimating the effective area of ​​the valve member 442 of the load applied by the exhaust. The reduced estimation error allows the actuator to be adjusted more accurately.

[0086] The above description is intended to be exemplary only and not restrictive. It should be understood that the features defined above according to any aspect of the present disclosure or any specific embodiment of the present disclosure can be used alone, or in combination with any other defined features in any other aspect or embodiment or for forming other aspects or embodiments of the present disclosure.

Claims

1. A turbine, comprising: wastegate chamber; a turbine housing defining a turbine inlet, the turbine housing comprising: a wastegate inlet passage defining a flow path between the turbine inlet and the wastegate chamber, wherein the wastegate inlet passage includes a turbine port proximate the turbine inlet and a non-circular valve port proximate the wastegate chamber, and a raised rim surrounding the non-circular valve port and conforming to a shape of the non-circular valve port, wherein the raised rim includes a first sealing surface; as well as A valve member comprising a second sealing surface, wherein the valve member is movable between a closed position in which the second sealing surface forms a seal with the first sealing surface to prevent fluid flow along the flow path and an open position in which the second sealing surface is spaced apart from the first sealing surface to allow fluid flow along the flow path.

2. A turbine according to any preceding claim, wherein the non-circular valve port defines a plane, and wherein the wastegate inlet passage extends along an axis which is oblique to the plane of the non-circular valve port.

3. A turbine according to claim 1 or 2, wherein the non-circular valve port has a major dimension defined by a maximum distance between opposing points on the valve port, wherein the second sealing surface has a minor dimension defined by a minimum distance between opposing points on an outer edge of the second sealing surface, and wherein the minor dimension of the second sealing surface is greater than the major dimension of the non-circular valve port. 4 . The turbine of claim 3 , wherein the second sealing surface defines a valve axis passing through a center of the second sealing surface, and wherein the valve member is free to rotate about the valve axis.

5. A turbine according to claim 3 or 4, wherein the non-circular valve port is elliptical, and wherein the elliptical valve port is defined by a major diameter and a minor diameter, and wherein the major dimension of the elliptical valve port is the major diameter of the elliptical valve port. 6 . The turbine of claim 5 , wherein the first sealing surface has an elliptical annular form.

7. A turbine according to any preceding claim, wherein the first sealing surface has a constant width. 8 . The turbine according to claim 7 , wherein the first sealing surface has a width of 5 mm or less.

9. A turbine according to any one of claims 3 to 8, wherein the second sealing surface is circular, and wherein the minor dimension of the second sealing surface is the diameter of the second sealing surface.

10. A turbine according to any one of claims 3 to 9, wherein the first sealing surface has a major dimension defined by a maximum distance between opposing points on an outer edge of the first sealing surface, and wherein the minor dimension of the second sealing surface is greater than the major dimension of the first sealing surface.

11. A turbine according to claim 10 when at least referring to claim 6, wherein the elliptical outer edge of the first sealing surface is defined by a major diameter and a minor diameter, and wherein the major dimension of the elliptical outer edge of the first sealing surface is the major diameter of the elliptical outer edge.

12. A turbine according to any preceding claim, wherein the raised rim and / or the wastegate inlet passage are formed in the turbine housing by interpolation milling.

13. A turbine according to any preceding claim, wherein the first sealing surface and the valve port are co-planar.

14. A turbine according to any one of claims 1 to 12, wherein the first sealing surface tapers away from the valve port, and wherein in the closed position the second sealing surface forms a seal with an inner edge of the first sealing surface.

15. A turbocharger comprising a turbine according to any preceding claim.

16. A method of manufacturing a turbine according to claim 1, the method comprising forming the raised periphery by interpolation milling.

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