Turbocharger turbine wheel

Abstract

A turbocharger turbine wheel includes a hub; and blades extending outward from the hub, wherein each of the blades includes a shroud edge, a leading edge, a trailing edge, a pressure side, and a suction side, wherein the shroud edge includes a minimum axial coordinate position where the shroud edge intersects the leading edge, and a maximum axial coordinate position where the shroud edge intersects the trailing edge, and wherein between the minimum axial coordinate position and the maximum axial coordinate position, each of the blades includes a first inclination angle at a first axial coordinate position defined about a first radial line; a second inclination angle at a second axial coordinate position defined about a second radial line; and an inclination angle recurved region at a recurved axial coordinate position between the first axial coordinate position and the second axial coordinate position.

Description

Technical Field

[0001] The subject matter disclosed herein generally relates to turbocharger turbine wheels for internal combustion engines. Background Art

[0002] A turbocharger may include a rotating group including a turbine wheel and a compressor wheel connected to each other by a shaft. For example, the turbine wheel may be welded or otherwise connected to the shaft to form a shaft and wheel assembly (SWA), and the compressor wheel may be assembled to the free end of the shaft. As an example, a shaft attached to one or more bladed wheels may be supported by one or more bearings disposed in a bearing housing, which may form a center housing rotating assembly (CHRA). During operation of the turbocharger, the SWA may be expected to rotate at speeds in excess of 200,000 rpm, depending on factors such as the size of the various components. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] A more complete understanding of the various methods, apparatus, components, systems, arrangements, etc. described herein, and their equivalents, may be had by reference to the following detailed description when taken in conjunction with the examples illustrated in the accompanying drawings, in which:

[0004] Figure 1 is a diagram of a turbocharger and an internal combustion engine together with a controller;

[0005] Figure 2 is a cross-sectional view of an example of a turbocharger assembly and an end view and a cross-sectional view of an example of a journal bearing;

[0006] Figure 3 is a side view of an example of a turbocharger;

[0007] Figure 4 are perspective and enlarged views of examples of shaft and wheel assemblies (SWAs);

[0008] Figure 5 is a cross-sectional view of an example of a turbine impeller;

[0009] Figure 6 are projection views of examples of blades of a turbine impeller having a radial inflow leading edge and projection views of examples of blades of a turbine impeller having a mixed flow inflow leading edge;

[0010] Figure 7 is a series of perspective views of examples of turbine impellers;

[0011] Figure 8 yes Figure 7 a series of views of the blades of a turbine wheel;

[0012] Fig. 9is a series of views of portions of an example of a turbine wheel;

[0013] Fig.10 is a series of graphs illustrating examples of turbine wheel blade characteristics;

[0014] Fig.11 yes Figure 7 A series of perspective cutaway views of a turbine impeller;

[0015] Fig.12 yes Figure 7 A series of plan cross-sectional views of a turbine impeller;

[0016] Fig.13 is a series of perspective views of examples of turbine impellers;

[0017] Fig.14 yes Fig.13 A series of plan cross-sectional views of a turbine impeller;

[0018] Fig.15 is an example of a graph that defines the tilt angle as positive or negative relative to a radial line;

[0019] Fig.16 are examples of graphs of normalized efficiency versus corrected flow rate for two different turbocharger turbine wheels;

[0020] Fig.17 are examples of graphs of normalized efficiency versus expansion ratio for two different turbocharger turbine wheels at two different rotating turbine wheel speeds; and

[0021] Fig.18 are examples of plots of normalized blade pressure versus corrected flow rate for two different turbocharger turbine wheels. DETAILED DESCRIPTION

[0022] Hereinafter, an example of a turbocharged engine system is described, followed by various examples of components, assemblies, methods, and the like.

[0023] Turbochargers are often used to increase the output of internal combustion engines. Figure 1 As an example, the system 100 may include an internal combustion engine 110 and a turbocharger 120. Figure 1 As shown, system 100 may be part of a vehicle 101, where system 100 is disposed in an engine compartment and connected to an exhaust duct 103 that directs exhaust gas to an exhaust outlet 109, for example, located behind a passenger compartment 105. Figure 1 In the example of , a processing unit 107 may be provided to process the exhaust gas (eg, to reduce emissions via catalytic conversion of molecules, etc.).

[0024] like Figure 1 As shown, the internal combustion engine 110 includes an engine block 118 housing one or more combustion chambers that operably drive a shaft 112 (e.g., via pistons), as well as an intake port 114 that provides a flow path for air to flow to the engine block 118 and an exhaust port 116 that provides a flow path for exhaust gas from the engine block 118.

[0025] The turbocharger 120 may function to extract energy from the exhaust gas and provide energy to the intake air, which may be combined with fuel to form combustion gases. Figure 1 As shown, the turbocharger 120 includes an air inlet 134, a shaft 122, a compressor housing assembly 124 for a compressor wheel 125, a turbine housing assembly 126 for a turbine wheel 127, another housing assembly 128, and an exhaust outlet 136. The housing assembly 128 may be referred to as a center housing assembly because it is disposed between the compressor housing assembly 124 and the turbine housing assembly 126.

[0026] exist Figure 1 12, the shaft 122 may be a shaft assembly including various components (e.g., consider a shaft and wheel assembly (SWA) in which the turbine wheel 127 is welded to the shaft 122, etc.). As an example, the shaft 122 may be rotatably supported by a bearing system (e.g., journal bearing(s), rolling element bearing(s), etc.) disposed in a housing assembly 128 (e.g., in a bore defined by one or more bore walls) such that rotation of the turbine wheel 127 causes rotation of the compressor wheel 125 (e.g., as rotatably coupled via the shaft 122). As an example, a center housing rotating assembly (CHRA) may include the compressor wheel 125, the turbine wheel 127, the shaft 122, the housing assembly 128, and various other components (e.g., a compressor side plate disposed at an axial position between the compressor wheel 125 and the housing assembly 128).

[0027] exist Figure 1 In the example of FIG. 1 , a variable geometry assembly 129 is shown as being partially disposed between the housing assembly 128 and the housing assembly 126. Such a variable geometry assembly may include vanes or other components to change the geometry of a passage to a turbine wheel space in the turbine housing assembly 126. As an example, a variable geometry compressor assembly may be provided.

[0028] exist Figure 1In the example of , a wastegate valve (or simply wastegate) 135 is positioned near the exhaust inlet of the turbine housing assembly 126. The wastegate valve 135 can be controlled to allow at least some exhaust gas from the exhaust port 116 to bypass the turbine impeller 127. Various wastegates, wastegate components, etc. can be applied to conventional fixed nozzle turbines, fixed vane nozzle turbines, variable nozzle turbines, twin scroll turbochargers, etc. As an example, the wastegate can be an internal wastegate (e.g., at least partially inside the turbine housing). As an example, the wastegate can be an external wastegate (e.g., operably coupled to a conduit in fluid communication with the turbine housing).

[0029] exist Figure 1 In the example of FIG. 1 , an exhaust gas recirculation (EGR) conduit 115 is also shown, which may optionally be provided with one or more valves 117 , for example to allow exhaust gas to flow to a location upstream of the compressor impeller 125 .

[0030] Figure 1 Also shown are an example arrangement 150 for flowing exhaust gas to an exhaust turbine housing assembly 152 and another example arrangement 170 for flowing exhaust gas to an exhaust turbine housing assembly 172. In arrangement 150, cylinder head 154 includes passages 156 disposed internally to direct exhaust gas from the cylinders to turbine housing assembly 152, while in arrangement 170, manifold 176 provides mounting of turbine housing assembly 172, e.g., without requiring any separate intermediate length of exhaust pipe. In example arrangements 150 and 170, turbine housing assemblies 152 and 172 may be configured for use with wastegates, variable geometry assemblies, and the like.

[0031] exist Figure 1In the example of controller 190, one or more processors 192, memory 194 and one or more interfaces 196 are shown. Such a controller may include circuits, such as circuits of an engine control unit (ECU). As described herein, various methods or techniques may be optionally implemented, for example, by combining a controller with control logic. The control logic may depend on one or more engine operating conditions (e.g., turbine rpm (revolutions per minute), engine rpm, temperature, load, lubricant, cooling, etc.). For example, a sensor may transmit information to the controller 190 via one or more interfaces 196. The control logic may rely on such information, and then the controller 190 may output a control signal to control the engine operation. The controller 190 may be configured to control lubricant flow, temperature, a variable geometry component (e.g., a variable geometry compressor or turbine), a wastegate (e.g., via an actuator), an electric motor, or one or more other components associated with an engine, a turbocharger (or multiple turbochargers), and the like. As an example, the turbocharger 120 may include one or more actuators and / or one or more sensors 198, which may be coupled to one or more interfaces 196 of the controller 190, for example. As an example, the wastegate 135 may be controlled by a controller that includes an actuator responsive to an electrical signal, a pressure signal, etc. As an example, the actuator for the wastegate may be a mechanical actuator that may, for example, be operable without a power source (e.g., consider a mechanical actuator configured to respond to a pressure signal supplied via a conduit).

[0032] Figure 2 An example of a turbocharger assembly 200 is shown including a shaft 220 supported by a journal bearing 230 disposed in a center housing 280 between a compressor wheel 240 and a turbine wheel 260; note that a thrust spacer 270 is shown between the compressor wheel 240 and a shoulder of the shaft 220 with respect to a hole in a back plate 290. Figure 2 As shown, the shoulder is formed by a step in the diameter of the shaft 220 from a smaller diameter to a larger diameter, thereby forming an annular axial surface (e.g., the side of the compressor). Figure 2 In the example of FIG. 1 , the thrust spacer 270 abuts the axial face of the shaft 220 on one side and the annular axial face of the compressor impeller 240 on the opposite side. The journal bearing 230 is at least partially located in the through-hole of the center housing 280 via the locating pin 210. The locating pin 210 can be fixed by being screwed into the socket 285 of the housing 280 and can be received by the hole 235 of the journal bearing 230, thereby locating the journal bearing 230 in the through-hole of the center housing 280. As an example, the locating pin 210 can locate the journal bearing 230 axially and azimuthally in the through-hole of the center housing 280.

[0033] As an example, the journal bearing 230 may move radially within the through hole of the center housing 280, for example, the journal bearing 230 may move radially up and down relative to the axis of the locating pin 210 while being restricted axially and azimuthally by the locating pin 210 (for example, the journal bearing 230 may be a semi-floating journal bearing).

[0034] For example, by being in an environment with ambient air or vehicle engine compartment air, Figure 2 The turbocharger assembly 200 can be either oil cooled or air cooled. The turbocharger can be cooled via one or more mechanisms. For example, the turbocharger can be cooled via air, water, oil, or other fluids. As for lubricant cooling (e.g., oil, whether natural, synthetic, etc.), there are some trade-offs. For example, if a carbonaceous lubricant reaches too high a temperature for too long a time (e.g., considering time-temperature correlations), carbonization (e.g., also known as coke formation or "coking") can occur. Coking can exacerbate heat generation and heat retention through any of a variety of mechanisms, and over time, coke deposits can shorten the life of a lubricated bearing system. As an example, coke deposits can result in reduced heat transfer and increased heat generation, which can cause failures in the bearing system.

[0035] To overcome coking, the turbocharger can be configured to improve lubricant flow. For example, a pump can pressurize the lubricant to increase the flow rate to reduce the residence time of the lubricant in the high temperature area. However, the increase in lubricant pressure can exacerbate various types of lubricant leakage problems. For example, an increase in lubricant pressure in the bearing system can cause lubricant to leak into the exhaust turbine, to the air compressor, or both. Escape via the exhaust turbine can cause observable smoke levels, while escape via the air compressor can cause lubricant to enter the intercooler, the combustion chamber (e.g., the combustion cylinder), etc.

[0036] As for the temperatures experienced during operation, they may depend on the temperature of the exhaust gas flowing to the exhaust turbine of the turbocharger, which exhaust gas temperature may depend on whether the internal combustion engine is gasoline-fueled or diesel-fueled; as an example, consider a diesel engine, which may have an exhaust gas temperature of approximately 860 degrees Celsius, and as an example, consider a gasoline engine, which may have an exhaust gas temperature of approximately 1050 degrees Celsius. Thus, a turbocharger in communication with the exhaust gas fluid of a gasoline-fueled internal combustion engine may experience higher temperatures when compared to a diesel-fueled internal combustion engine. In addition, consider Figure 1 The example arrangements 150 and 170 , in which the turbine housing assemblies 152 and 172 are in close proximity to the combustion cylinders, may cause the turbine housing assemblies 152 and 172 to experience higher exhaust temperatures and / or higher ambient temperatures.

[0037] Figure 3An example of a turbocharger 300 is shown including a compressor assembly 340 having a compressor housing for a compressor impeller, a turbine assembly 360 having a turbine housing for a turbine impeller, a center housing 380 for one or more bearings or bearing assemblies to rotatably support a shaft of a shaft and wheel assembly (SWA), and an actuator 350 having a linkage 354 to a control arm assembly 358 for a wastegate of the turbine assembly 360. The turbocharger 300 may include Figure 2 One or more of the components shown. Figure 2 , the exhaust inlet of the turbine assembly 360 is not visible because it is on the opposite side. The general flow direction of the air or exhaust gas is indicated by the arrows. The actuator 350 is shown mounted to the compressor assembly 340, which can help reduce the temperature experienced by the actuator 350 (e.g., compared to mounting the actuator on the turbine housing). The turbocharger 300 can be, for example, Figure 1 As an example, the turbine assembly 360 may be optionally such as in Figure 1 Arranged in one of the example arrangements 150 or 170 .

[0038] Figure 4 A perspective view of a shaft and wheel assembly (SWA) 400 is shown. As shown, the SWA 400 includes a shaft 420, a seal portion 440, and a turbine wheel 460, wherein the turbine wheel 460 includes a nose 470, a rear wheel disk 480, and blades 490. The turbine wheel 460 can be a single unitary material and is referred to as a single component or single piece. A portion of the turbine wheel 460 can be referred to as a hub 465. For example, the rear wheel disk 480 can be a portion of the hub 465 from which the blades 490 extend. The hub 465 can include the rear wheel disk 480 and the nose 470, and extend the length of the turbine wheel as indicated by the axial length ztw measured along the rotational z-axis of the SWA 400.

[0039] As an example, the sealing portion 440 may be formed partially by the turbine wheel 460 and partially by the shaft 420, may be formed by the shaft 420, or may be formed by the turbine wheel 460. As an example, the sealing portion 440 may be formed at least partially by the shaft 420. The sealing portion 440 may be defined by an outer radius.

[0040] like Figure 4As shown, SWA 400 may include a shoulder or step down from turbine wheel 460 toward shaft 420. For example, the shoulder may step down from the outer surface of shaft joint portion 450 to outer surface 455, which may have a radius equal to or approximately equal to the radius of seal portion 440. Shaft joint portion 450 may include a surface that is an annular axial face, which may form a portion of the shoulder.

[0041] As an example, the shaft joint portion 450 may include a shaft joint surface that may be defined in part by a shaft joint radius. For example, consider a shaft joint surface that may be used to connect a shaft to a turbine wheel (e.g., via welding, etc.). In such an example, the shaft joint surface of the turbine wheel may be a mating surface that mates with a turbine wheel connection surface of the shaft, where the two surfaces may be in close or direct contact and connected (e.g., via welding). As an example, the shaft joint surface may be an annular surface that may be welded to a surface of the shaft to form a SWA (e.g., forming one or more welds).

[0042] SWA 400 may include dimensions, such as, for example, dimensions of a compressor wheel portion zc (which may include one or more guide surfaces, a set of threads, etc.), and a bearing portion zj (which may include one or more journal surfaces (e.g., a compressor side journal surface and a turbine side journal surface, etc.)).

[0043] like Figure 4 As shown, the sealing portion 440 can include one or more annular grooves that can be configured to receive one or more sealing elements (e.g., one or more sealing rings). As shown, the sealing portion 440 can be defined in part by an axial dimension zsp. As an example, the sealing element can be a split ring, such as a piston ring. As mentioned, the SWA can be formed by welding the shaft to the turbine wheel, so that the resulting SWA has a shaft and a turbine wheel arranged and fixed along a common rotation axis.

[0044] Figure 4A portion of SWA 400, and in particular, an enlarged perspective view of a turbine wheel 460, is shown. As an example, a turbine wheel may be defined using a diameter, which may be a circle that inscribes a feature of the turbine wheel. For example, where a turbine wheel includes an odd number of blades, the diameter may not be drawn as a line from the leading edge of one blade to the leading edge of another blade. In such an example, the diameter may be defined via a circle that inscribes the leading edge of the blade, or, for example, mathematically twice the radius. A turbine wheel may be defined by an inlet section diameter (inducer diameter) (e.g., associated with exhaust gas inflow) and an outlet section diameter (exducer diameter) (e.g., associated with exhaust gas outflow). As an example, the inlet section diameter may exceed the outlet section diameter. As an example, the trim of a turbine wheel may be defined using the inlet section diameter of the turbine wheel and its outlet section diameter. Where a diameter is mentioned, it may refer to the diameter of a circle that may be drawn relative to a feature of the turbine wheel. As an example, a turbine wheel may be defined in a cylindrical coordinate system including axial, radial, and azimuthal coordinates (e.g., r, z, and θ).

[0045] As an example, the balancing process may change one or more dimensions of the turbine wheel, such as by removing material. For example, consider removing material from the nose 470 of the turbine wheel 460 of the SWA 400. As shown, the outer diameter of the nose 470 is smaller than the outer diameter of the rear disk 480. Another option may be to remove material from the rear disk 480. As an example, material may be removed from the shaft joint portion 450. In such an example, the material removal may have a minimal effect on the ability of the rear disk 480 to support the blades 490.

[0046] like Figure 4 As shown in the example of , the exhaust turbocharger turbine impeller 460 may include a hub 465, the hub 465 including a nose 470, a rear wheel disk 480, a shaft joint portion 450 (e.g., as part of the rear wheel disk 480) and a rotation axis (z-axis); blades 490 extending from the hub 465 to define an exhaust flow path, wherein each of the blades 490 includes a leading edge, a trailing edge, a hub profile, a shroud profile, a pressure side and a suction side; wherein the rear wheel disk 480 includes an outer peripheral radius measured from the rotation axis of the hub 465 and an intermediate radius at the outer periphery of the shaft joint portion 450 measured from the rotation axis of the hub 465.

[0047] As for the shaft joint portion 450 , it is shown as being generally cylindrical. As an example, the rear wheel disc 480 can be defined as a lower portion of the hub 465 that includes at least a portion of the shaft joint portion 450 and extends outwardly to the maximum periphery of the rear wheel disc 480 .

[0048] As explained, the shaft joint portion 450 can be connected to the sealing portion 440, which can be an integral part of the shaft 420. As an example, the sealing portion 440 can be welded to the shaft joint portion 450 to form a welded joint that will permanently connect the shaft 420 and the turbine wheel 460 to form the shaft and wheel assembly (SWA) 400.

[0049] refer to Figure 2 , the seal portion is shown as part of the shaft 220 and is connected to the turbine wheel 260 to form the SWA. The seal portion may include Figure 2 One or more annular grooves are shown in which one or more corresponding sealing elements (e.g., sealing rings) can be at least partially disposed to form one or more seals between the lubrication area of ​​the center housing 280 and the exhaust area in which the turbine wheel 260 is disposed. As shown, the center housing 280 includes a turbine-side bore in which the sealing portion and the seal are seated. The bore includes a bore wall in which the seal can contact the bore wall (e.g., consider the piston ring as a split ring that can be compressed during installation and then expand once installed to form a seal).

[0050] As an example, the shaft may be made of a material that is the same as the material of the turbine wheel or different from the material of the turbine wheel. In the case where the materials are different, the materials may generally be suitable for welding so that a SWA can be formed. As mentioned, the compressor impeller may be made of a material that has a lower specific gravity than the material of the turbine wheel. In general, the compressor impeller experiences operating temperatures that are lower than the operating temperature of the turbine impeller. As an example, the turbine impeller may be made of a nickel alloy. For example, consider a NiCrFe-based alloy such as HASTALLOY TM Materials, INCONEL TM materials, etc.) or other alloys. In contrast, the compressor impeller can be made of a lighter material, such as, for example, aluminum or an aluminum alloy. The specific gravity of the turbine impeller material can be two or more times that of aluminum (for INCONEL TM 625 material, specific gravity is about 2.7 to about 8.4).

[0051] exist Figure 2 In the embodiment, the rotating assembly may include a shaft 220 and a turbine wheel 260 as a SWA, and a compressor wheel 240 and a nut (e.g., for a compressor wheel having a through hole). As an example, a so-called holeless compressor wheel may be used, wherein the compressor wheel may be connected to the shaft without using an end nut.

[0052] The rotating assembly may have a mass defined by the sum of the masses of the individual components that make up the rotating assembly. As mentioned above, the exhaust gas flow to the exhaust gas turbine disposed in the turbine housing may be the driver for the rotation of the rotating assembly, wherein the mass and other factors may determine how much exhaust gas must flow before rotation begins.

[0053] Figure 5 An example turbine wheel 460 is shown in cross-sectional view. Figure 5 A shaft joint portion 450 is shown having a shoulder 452 and surfaces 453, 455, and 457. As shown, surface 457 may be a surface that serves as a mating surface for the shaft joint portion 450 for connecting the shaft to a turbine wheel 460. As mentioned, the outer diameter of the shaft joint portion 450 at surface 455 may be substantially the same as the outer diameter of the seal portion (e.g., see seal portion 440).

[0054] like Figure 5 As shown in the example of , turbine wheel 460 includes various blade features, such as leading edge 491 (or inlet segment edge), trailing edge 499 (or outlet segment edge), rear wheel point 492 of leading edge 491, tip point 493 of leading edge 491, hub point 494 of trailing edge 499, and tip point 495 of trailing edge 499. As shown, turbine wheel 460 has a blade outer diameter at tip point 493 of leading edge 491 (e.g., inlet segment edge); another blade outer diameter at tip point 495 of trailing edge 499 (e.g., outlet segment edge); and a blade diameter at hub point 494 at trailing edge 499 (e.g., outlet segment edge).

[0055] As mentioned, a circle may inscribe the blade feature to define a diameter. Figure 5 In FIG. 1 , the diameters Dle (diameter leading edge) and Dte (diameter trailing edge) are not shown as corresponding to circles, but rather to specific cross-sections, where the diameter of one circle will be slightly larger than Dle and the diameter of the other circle will be slightly larger than Dte.

[0056] like Figure 5 As shown in the example of FIG. 4 , the dashed line represents a hub profile 496 of the blade 490 - 5 , while the solid line 498 represents at least a portion of the shroud profile of the blade 490 - 5 .

[0057] Figure 6 A plan view of an example of a blade 490 is shown, and Figure 5 Describes the various points and contours. Figure 6 Also shown is an arrow indicating the intended flow direction of the exhaust gas from the leading edge 491 to the trailing edge 499, where two adjacent vanes define a flow path (e.g., an exhaust flow path) for the exhaust gas. As mentioned, one side of the vane can be defined as the pressure side, while the opposite side of the vane can be defined as the suction side. Figure 6 The plan view of is a projection view, so that the concave and convex shapes of the blade 490 cannot be seen. Figure 6 , blades 490 may be defined with respect to radial and axial coordinates. As an example, a polar angle plot may be used to provide additional information defining blades 490. For example, consider a plot of the wrap angle along the mid-camber line. As an example, blades 490 may be defined using one or more equations, parameters, etc. of an airfoil or impeller.

[0058] As an example, the turbine wheel may be a radial flow turbine wheel (eg, radial incoming flow), or may be a mixed flow turbine wheel (eg, mixed incoming flow), where an angle may define at least a portion of a leading edge such that the incoming exhaust gas has both a radial component and an axial component. Figure 6 An example of a mixed flow turbine impeller blade 4090 is shown where the leading edge 4091 is at an angle other than 90 degrees relative to the r-axis and at an angle other than 0 degrees relative to the z-axis (e.g., about 1 degree to about 89 degrees). As an example, the turbine impeller blades may be radially stacked or not radially stacked (e.g., non-radially stacked).

[0059] Figure 7 Two perspective views of an example turbine wheel 760 are shown, where the example turbine wheel 760 includes eleven blades, one of which is labeled blade 790; note that the turbine wheel may include a plurality of blades, for example, in the range of from about 5 blades to about 30 blades. Figure 7 In the example of FIG. 7 , turbine wheel 760 may be a radial flow turbine wheel.

[0060] Figure 8 An enlarged side view of turbine wheel 760 is shown along with a meshed view of one blade, such as blade 790, and a projected view of one blade, such as blade 790, and the general direction of airflow. In the projected view (lower right), the dashed line represents a meridian extending from the leading edge (LE) to the trailing edge (TE) between the hub profile and the shroud profile. As an example, one or more features of the blade may be described relative to a meridian, meridian coordinates, and the like. For example, consider a normalized meridian coordinate system having zero at the leading edge and unity (1) at the trailing edge. In Figure 8 For reference Figure 5 and Figure 6 Points 492, 493, 494 and 495 are used to understand the various points 792, 793, 794 and 795. Figure 4 , Figure 5 and Figure 6 Various other features described may be used to describe Figure 7 Various features of turbine impeller 760.

[0061] Fig. 9An example of a blade 990 as a section of a turbine wheel including a plurality of blades is shown. As shown, blade 990 includes various points 992, 993, 994, and 995, which may be defined in a cylindrical coordinate system. Fig. 9 In the example blade 990, three radial lines are shown, labeled r1, r2, and r3, which have corresponding axial coordinates z1, z2, and z3, where each of the three radial lines can be referred to as a radial fiber. Fig. 9 In FIG. 1 , the cross-sectional area and shape of the hub and blades 990 are shown at three different r,θ planes z1, z2 and z3. As an example, the blades can be defined in part by thickness, which can be shown as thickness Th at a specific axial dimension and a specific radial dimension. B (z, r). The blade thickness may be the distance between the pressure surface (eg, pressure side) and the suction surface (eg, suction side) of the blade. Fig. 9 In the example of , the blades 990 may have different thicknesses in different areas. As an example, the blades may be thinner at the shroud edge (e.g., along the shroud contour) and thicker at the hub edge (e.g., along the hub contour). Fig. 9 As shown, the radius of the hub may vary, wherein the hub may have a smaller radius near the nose and a larger radius near the base (eg, where the blades 990 connect to the rear disc).

[0062] As shown, blades 990 are radially stacked (RS) because a radial line can be drawn from the hub to the leading edge at z1, r1, from the hub to the shroud edge at z2, r2, and from the hub to the shroud edge at z3, r3. Fig. 9 , the radial lines have an origin along the z-axis, which is the axis of rotation of the turbine wheel including blades 990. Radial stacking may be beneficial with respect to turbine wheel stresses because radial stacking helps reduce blade stresses that are excessive at high rotational speeds (e.g., rotational speeds exceeding 10,000 rpm, 100,000 rpm, or more).

[0063] exist Fig. 9 In , the radial lines of blade 990 are also center lines because each of the radial lines is centered between the suction side and the pressure side of blade 990. Another type of line that can be used to describe a blade is the camber line (or camberline), which is the center line of the blade profile that extends from the leading edge to the trailing edge, midway between the pressure side (pressure surface) and the suction side (suction surface). Fig. 9In the example blade 990 of FIG. 1 , one or more camber lines may form a camber sheet or camber surface extending from the leading edge to the trailing edge of the blade 990, wherein at each axial position, radial lines extend from the hub profile of the camber surface to the shroud profile. For example, the portions of radial lines r1, r2, and r3 between the hub profile and the leading edge, shroud edge, and trailing edge are all in the camber surface of the blade 990. For a given blade, where the radial lines at the axial position between the hub profile and the leading edge, shroud profile, or trailing edge do not coincide with the camber surface, that is, the blades are not radially stacked.

[0064] Fig. 9 Also shown are two examples of non-radially stacked (¬RS) blades that may be defined by a tilt angle. As shown, the tilt angle may be defined relative to a radial line, where the tilt angle may be toward the suction side or toward the pressure side. As an example, the tilt angle may be defined as negative when it is toward the suction side and positive when it is toward the pressure side. As shown, for radially stacked blades, the tilt angle is zero. As an example, a blade may be non-radially stacked and include a tilt angle that is negative in some regions and positive in some regions.

[0065] As an example, a blade may be defined by an average tilt angle at a specific z-axis position. For example, in the case of blade bending, the tilt angle may vary relative to the radial position. In such an example, the tilt angle may increase and / or decrease relative to the radial position. As an example, the blade may be tilted toward the pressure side in a region extending inward from the outer edge of the blade, and then tilted toward the suction side. In such an example, the blade may have a positive tilt angle over the radial length, and then may have a negative tilt angle over the radial length. As an example, the blade may tilt and then return to the radial line. For example, consider a blade that tilts toward the pressure side and then approaches the outer edge along a radial line. In such an example, the blade may have a positive tilt angle relative to the radial position and a zero tilt angle relative to one or more radial positions. As for the average tilt angle, in such an example, a series of angles may be used for corresponding radial positions where the average tilt angle is positive. As mentioned, the blade may be characterized by a tilt angle, which may be negative, zero or positive, wherein the tilt angle may be an average tilt angle or, for example, a local tilt angle at a radial position that deviates from the radial line.

[0066] Fig.10 Graphs 1010 and 1030 corresponding to example blade 790 are shown. Graph 1010 shows a meridian (M) along a normalized plane of the projected axial and radial axes of blade 790, wherein the hub profile and shroud profile are shown along with the leading edge (LE) and the trailing edge (TE). As shown, the shroud profile may be represented by a shroud edge (SE).

[0067] Graph 1030 illustrates the hub profile, meridian (e.g., meridian profile), and shroud profile relative to θ and normalized z-axis coordinate position. As shown in graph 1030, blade 790 includes a non-radial stack portion tilted toward the suction side (SS) and a non-radial stack portion tilted toward the pressure side (PS). Graph 1030 also illustrates an approximate inflection point (IP), where blade 790 may include an approximately radially stacked region as a transition region where, moving along the z-axis, blade 790 transitions from tilting in one direction to tilting in another opposite direction (e.g., suction side tilt to pressure side tilt, negative tilt angle to positive tilt angle, etc.).

[0068] In the graph 1030, the axial height of the leading edge (LE) and the axial range of the inflection point or recurved region can be defined. For example, the blade 790 can include a transition point or transition region that is within the axial range from the point 793 where the leading edge intersects the shroud edge to the point 795 where the shroud edge intersects the trailing edge. As an example, the recurve can refer to the sign of the inclination angle changing from positive to negative or from negative to positive. As an example, the inflection point can be a point where the inclination angle is zero (e.g., neither positive nor negative).

[0069] Fig.11 The turbine wheel 760 is shown in a series of cross-sectional cutaway views at different axial positions (Z1, Z2, Z3, Z4, Z5, Z6, Z7 and Z8) along the z-axis, which is the axis of rotation of the turbine wheel 760. In each of the views, radial lines can be drawn to determine whether the blades are radially stacked, non-radially stacked, tilted or non-tilted, where the tilt can be defined by one or more tilt angles including at least one non-zero tilt angle at at least one radial position. As shown, axial position Z1 is near the rear disk and axial position Z8 is near the nose. In each of the cutaway views, the blade thickness can be seen, which can vary relative to the axial and radial dimensions. In each of the cutaway views, a flat planar surface formed by a portion of the hub and a portion of the blade can be seen. As shown with respect to Fig. 9 As mentioned, the hub can be represented in part by a radius (e.g., or diameter), where the radius can decrease in a direction from the rear disk to the nose (e.g., from Z1 to Z8). In various cross-sectional views, the length of the blade from the hub appears to increase (e.g., as the hub radius becomes smaller); note that the transition may occur at the end of the leading edge (e.g., the tip of the leading edge) where it intersects the shroud edge. As an example, for a mixed flow turbine impeller, the leading edge of the blade may extend beyond the rear disk such that at least a portion of the leading edge may have a radius greater than the radius of the rear disk. For example, considering the cross-sectional view at Z4, for a mixed flow turbine impeller, the leading edge may extend to a radius greater than the radius of the rear disk.

[0070] Fig.12 Two cross-sectional views of a turbine wheel 760 viewed from the rear disk side are shown, wherein the blades have a negative tilt angle at the rear disk at a z-axis position near the ZLSS, and wherein the blades have a positive tilt angle at the nose at a z-axis position near the ZLPS. In such a turbine wheel, the blades transition from negative tilt to positive tilt when moving axially from the rear disk to the nose of the turbine wheel, wherein the transition occurs within an axial range defined by a shroud profile (e.g., a shroud edge, SE), which range is bounded by a leading edge at a lower axial position (e.g., a minimum axial position of the shroud profile) and a trailing edge at a higher axial position (e.g., a maximum axial position of the shroud profile) (see also, e.g., Fig.10 1010 and 1030 showing the leading edge and shroud profiles). Fig.12 In an example of the embodiment of the present invention, at the axial position ZLSS, the tilt angle may be in the range of about negative 10 degrees to about negative 20 degrees, and at the axial position ZLPS, the tilt angle may be in the range of about greater than 0 degrees to about positive 10 degrees. In such an example, the tilt angle may be measured relative to a point at the hub of the blade (e.g., the hub profile) and a point at the shroud edge of the blade, wherein the point at the hub of the blade is along a radial line, wherein the point at the shroud edge of the blade does not fall on the radial line (e.g., such that the tilt angle is not zero). As for the values ​​of the axial positions ZLSS and ZLPS, for example, by matching the shape and / or size (e.g., radius, etc.) of the blade, refer to Fig.11 to determine the view.

[0071] Fig.13 Two perspective views of an example of a turbine impeller 1360 are shown, wherein the example turbine impeller 1360 includes eleven blades, wherein one of the blades is labeled as blade 1390; note that the turbine impeller may include a plurality of blades, for example, in a range from about 5 blades to about 30 blades. The example turbine impeller 1360 includes blades, wherein the leading edge of each blade at least partially extends a distance beyond the rear wheel disk. The example turbine impeller 1360 may, for example, be a mixed flow turbine impeller, wherein the leading edge of the blade may be partially defined by a cone angle. The leading edge of the blade of the mixed flow turbine impeller may be straight, curved, straight and curved, etc., and may define a line that is not parallel to the axis of rotation of the mixed flow turbine impeller (e.g., at an angle to the axis of rotation). As an example, the turbine impeller may be a radial flow turbine impeller or a mixed flow turbine impeller, wherein the mixed flow turbine impeller includes radial flow and axial flow at the leading edge of the blade. As an example, radial flow turbine wheels and / or mixed flow turbine wheels may be non-radially stacked, for example at least in part due to tilting.

[0072] Fig.14Two cross-sectional views of a turbine wheel 1360 as viewed from the rear disk side are shown, wherein the blades have a negative tilt angle at the rear disk at a z-axis position near the ZLSS, and wherein the blades have a positive tilt angle at the nose near the ZLPS. In such a turbine wheel, the blades transition from negative tilt to positive tilt as they move axially from the rear disk to the nose of the turbine wheel, wherein the transition occurs within an axial range defined by a shroud profile (e.g., a shroud edge, SE) bounded by a leading edge at a lower axial position (e.g., a minimum axial position of the shroud profile) and a trailing edge at a higher axial position (e.g., a maximum axial position of the shroud profile). Fig.14 In an example of axial position ZLSS, the tilt angle may be in the range of approximately less than 0 degrees to approximately negative 10 degrees, and at axial position ZLPS, the tilt angle may be in the range of approximately greater than 0 degrees to approximately positive 10 degrees. In such an example, the tilt angle may be measured relative to a point at the hub of the blade (e.g., the hub profile) and a point at the shroud edge of the blade, wherein the point at the hub of the blade is along a radial line and wherein the point at the shroud edge of the blade does not fall on the radial line (e.g., such that the tilt angle is not zero). As for the values ​​of axial positions ZLSS and ZLPS, for example, by matching the shape and / or size (e.g., radius, etc.) of the blade with reference to a view of turbine wheel 1360 such as Fig.11 The view is determined by Fig.12 and Fig.14 As shown, a turbine wheel may include blades including a negative pitch angle and a positive pitch angle, wherein a transition between the negative pitch angle and the positive pitch angle occurs relative to an axial dimension defined along an axis of rotation of the turbine wheel.

[0073] As an example, the tilt angle gradient may be in the range from about negative 50 degrees to about positive 50 degrees, in the range from about positive 50 degrees to about negative 50 degrees, in the range from about negative 40 degrees to about positive 40 degrees, in the range from about positive 40 degrees to about negative 40 degrees, in the range from about negative 30 degrees to about positive 30 degrees, in the range from about positive 30 degrees to about negative 30 degrees, in the range from about negative 20 degrees to about positive 20 degrees, in the range from about positive 20 degrees to about negative 20 degrees, in the range from about negative 10 degrees to about positive 10 degrees, in the range from about positive 10 degrees to about negative 10 degrees, in the range from about negative 5 degrees to about positive 5 degrees, in the range from about positive 5 degrees to about negative 5 degrees, etc. As an example, the tilt angle gradient may be symmetric or asymmetric with respect to negative and positive values. For example, consider a tilt angle gradient whose maximum negative tilt angle value (e.g., maximum negative value) has a tilt angle absolute value that is less than the tilt angle absolute value of the maximum positive tilt angle value, or whose maximum positive tilt angle value has a tilt angle absolute value that is less than the tilt angle absolute value of the maximum negative tilt angle value (e.g., maximum negative value). As an example, the tilt angle gradient can be defined using tilt angles measured relative to a point at a hub of the blade (e.g., a hub profile) and a point at a shroud edge of the blade, wherein the point at the hub of the blade is along a radial line, wherein the point at the shroud edge of the blade does not fall on the radial line where the tilt angle is not zero, and wherein the point at the shroud edge of the blade falls on the radial line where the tilt angle is zero, such as the tilt angle that can mark an inflection point (e.g., or a recurved region, etc.).

[0074] As mentioned, it is possible to Figures 1 to 14 One or more of the features shown in the figure may be used to describe a turbine impeller, a shaft and wheel assembly (SWA), a turbine impeller blade, etc. For example, a turbine impeller may include blades, wherein the turbine impeller may include Figures 4 to 14 One or more of the features described in. Figure 7 and Fig.13 The example turbine wheels 760 and 1360 include blades extending outward from a hub, wherein each of the blades includes a shroud edge (e.g., SE), a leading edge (e.g., LE), a trailing edge (e.g., TE), a pressure side (e.g., PS), and a suction side (e.g., SS), wherein the shroud edge includes a minimum axial coordinate position where the shroud edge intersects the leading edge, and a maximum axial coordinate position where the shroud edge intersects the trailing edge, and wherein, between the minimum axial coordinate position and the maximum axial coordinate position, each of the blades includes a first inclination angle at a first axial coordinate position defined about a first radial line, a second inclination angle at a second axial coordinate position defined about a second radial line, and an inclination angle recurved region at a recurved axial coordinate position between the first axial coordinate position and the second axial coordinate position.

[0075] Fig.15 An example of a graph 1500 is shown that can be used to define tilt angles, where the tilt angle toward the suction side is negative and the tilt angle toward the pressure side is positive with respect to a radial line that defines a zero tilt angle (no tilt). The graph 1500 includes dashed lines that indicate that the tilt of the suction side and / or pressure side of the blade can be different from linear with respect to a radial dimension between the hub side and the shroud side of the blade. As an example, the tilt can be linear in one or more portions and / or curved in one or more portions. As an example, the blade can be at least partially defined by a line between the hub side and the shroud side, such that a line can be drawn from a point of the blade on the hub side and a point of the blade on the shroud side, where for stacks other than radial stacks, the line does not coincide with a radial line passing through the axis of rotation of the turbine wheel, the point of the blade on the hub side, and the point of the blade on the shroud side. As an example, a pressure surface (eg, pressure side) and / or a suction surface (eg, suction side) of the blade may be linear along at least a portion of such a line and / or may be curved such that at least a portion of the blade does not fall on such a line.

[0076] As an example, a Fig.15 The graph 1500 of the graph may be used to characterize one or more regions of a blade of a turbine impeller. For example, consider that between a minimum axial coordinate position and a maximum axial coordinate position of the blade, the blade includes a first tilt angle at a first axial coordinate position defined about a first radial line, a second tilt angle at a second axial coordinate position defined about a second radial line, and a tilt angle recurved region at a recurved axial coordinate position between the first axial coordinate position and the second axial coordinate position. In this example, each of the first radial line and the second radial line may be represented as follows: Fig.15 The vertical radial line in the graph 1500 of , which may be a radial line at a specific corresponding axial coordinate position (see also, for example, Fig.12 and Fig.14 As for the example of the first tilt angle and the second tilt angle, one may be positive (e.g., toward the pressure side of the blade) and the other may be negative (e.g., toward the suction side of the blade). In such an example, the tilt angle may provide enhanced performance. For example, consider the enhanced efficiency of an exhaust turbine of a turbocharger including a turbine wheel having such blades (e.g., individual blades having both positive and negative tilt).

[0077] Fig.16An example of a graph 1600 of efficiency versus corrected flow rate (e.g., kg / s) for two different turbine impellers is shown, one having radially stacked blades without tilt, and the other having blades having both positive and negative tilt (e.g., positive tilt angle and negative tilt angle), wherein each of the blades includes a transition region for transitioning from positive tilt to negative tilt or from negative tilt to positive tilt. In the example graph 1600, the turbine impeller is in an assembly that is a variable geometry turbine assembly (e.g., VGT or VNT). As shown in the graph 1600, by using blades having both positive tilt and negative tilt, the maximum efficiency is improved. In addition, the efficiency is improved over a wide range of corrected flow rates, especially at lower corrected flow rates, which can help reduce various types of turbine effects in vehicles utilizing turbocharged internal combustion engines. For example, for a turbocharger including a turbine wheel having blades where each of the blades includes both positive and negative pitch, the turbocharger may experience less turbo lag (e.g., be more responsive to increases in power demand) when compared to a turbine wheel having radially stacked, non-pitched blades.

[0078] As explained, turbine blades are traditionally radially stacked, meaning that at a given meridian location, the tilt angle from the hub to the shroud is constant (represented by straight radial filaments), which is done to minimize stresses in the blades and at the blade root fillet, as well as to facilitate manufacturing. However, as shown in graph 1600, benefits in aerodynamic performance may be gained by using non-radially stacked blades.

[0079] Fig.17 An example of a graph 1700 of normalized efficiency versus expansion ratio and rotating turbine wheel speed (RPM) for two different turbine wheels is shown, one having radially stacked blades without tilt, and the other having blades having both positive and negative tilt (e.g., positive tilt angle and negative tilt angle), wherein each of the blades includes a transition region for transitioning from positive tilt to negative tilt or from negative tilt to positive tilt. In the example graph 1700, the turbine wheel is in an assembly that does not include a variable geometry turbine assembly (e.g., VGT or VNT). As shown in the example graph 1700, the normalized efficiency is improved at RPM 1 (e.g., 110,000 RPM) for a turbine impeller with positive / negative tilted blades over the entire range of expansion ratios (e.g., about 1 to about 5), and the normalized efficiency is improved at RPM 2 (e.g., 170,000 RPM) for a turbine impeller with positive / negative tilted blades over most expansion ratios, particularly in the lower half of the expansion ratio (e.g., about 1 to about 3.5).

[0080] Fig.18An example of a graph 1800 of normalized blade pressure versus normalized cord length for two different turbine wheels is shown, one having radially stacked blades without tilt, and the other having blades having both positive and negative tilt (e.g., positive tilt angle and negative tilt angle), wherein each of the blades includes a transition region for transitioning from positive tilt to negative tilt or from negative tilt to positive tilt. As shown, the turbine wheel with the positive / negative tilt blades has a generally lower normalized blade pressure.

[0081] Example graph 1800 illustrates normalized blade tip pressure distribution relative to normalized line length in a manner that shows that tilting has a substantial effect on reducing blade static pressure, where the reduction is greater on the pressure side (e.g., pressure surface) than on the suction side (e.g., suction surface), which results in a reduced pressure difference between the pressure side and the suction side, which physically means that tip leakage flow / losses are generally lower and flow acceleration is faster on the pressure side, while the thickness of the boundary layer is generally thinner than on the suction side, which physically means that secondary flow losses inside the blade passage (e.g., defined by two adjacent blades) are lower.

[0082] In the example graph 1800, various normalized blade pressure values ​​can be used to characterize the reduction of blade pressure. For example, at the normalized line length value, the value of the normalized blade pressure or the actual blade pressure can be compared. As shown in the figure, at a normalized line length of about 0.90 (see, for example, the vertical dashed line), the pressure side normalized blade pressure is reduced by about 0.08 (e.g., 1.16-1.08), while the suction side normalized blade pressure is reduced by about 0.065 (e.g., 1.045-0.98). As another example, at a normalized line length of about 0.05, the pressure side normalized blade pressure is reduced by about 0.04 (e.g., 1.03-0.98), while the suction side normalized blade pressure is reduced by about 0.03 (e.g., 0.99-0.96). The aforementioned values ​​and / or other values ​​can be expressed as percentages, absolute values, etc., to characterize how blades with positive and negative inclinations can improve the performance of the exhaust turbine of the turbocharger.

[0083] As an example, a turbine wheel may include a blade inlet section region having a non-constant tilt angle from the hub to the shroud. As an example, the tilt in the blade inlet section region may be positive (towards the pressure side) or negative (towards the suction side). As an example, gradually along the meridional direction, the blade may have a decreasing tilt angle variation, which may become zero (e.g., radial stacking) and then start in absolute terms, but increase again in the opposite direction until the blade exit section region. As an example, the blade may include an inflection point or a recurved region, which may be located at a meridional position between the leading edge and the trailing edge. As an example, the inflection point or the recurved region may be within the axial limit defined by the shroud edge of the blade.

[0084] As an example, a turbine wheel may include blades that reduce secondary losses and tip leakage losses within the blade passages, resulting in improved efficiency. For example, consider the data of graph 1600, which shows an increase in efficiency over a corrected flow rate range; the data of graph 1700, which shows an increase in efficiency over a range of expansion ratios; and the data of graph 1800, which shows a reduction in normalized blade pressure.

[0085] As an example, a turbine wheel of a turbocharger may include blades that may be characterized by tilt parameters (eg, the amount, evolution, and direction of tilt, and the location of an inflection point or recurvature region).

[0086] As an example, a turbocharger turbine wheel may include a hub; and blades extending outward from the hub, wherein each of the blades includes a shroud edge, a leading edge, a trailing edge, a pressure side, and a suction side, wherein the shroud edge includes a minimum axial coordinate position where the shroud edge intersects the leading edge, and a maximum axial coordinate position where the shroud edge intersects the trailing edge, and wherein, between the minimum axial coordinate position and the maximum axial coordinate position, each of the blades includes a first inclination angle at a first axial coordinate position defined about a first radial line, a second inclination angle at a second axial coordinate position defined about a second radial line, and an inclination angle recurved region at a recurved axial coordinate position between the first axial coordinate position and the second axial coordinate position.

[0087] As an example, a turbocharger turbine wheel may include a hub including an axis of rotation, a rear wheel disk, and a nose, wherein the axis of rotation defines an axial coordinate (z) in a cylindrical coordinate system including a radial coordinate (r) and an azimuthal coordinate (θ) in an intended direction of rotation about the axis of rotation; and blades extending outward from the hub, wherein each of the blades includes a shroud edge, a leading edge, a trailing edge, a pressure side, and a suction side, wherein the shroud edge includes a minimum axial coordinate position where the shroud edge intersects the leading edge, and a maximum axial coordinate position where the shroud edge intersects the trailing edge, and wherein, between the minimum axial coordinate position and the maximum axial coordinate position, each of the blades includes a first tilt angle at a first axial coordinate position defined about a first radial line, a second tilt angle at a second axial coordinate position defined about a second radial line, and a tilt angle recurved region at a recurved axial coordinate position between the first axial coordinate position and the second axial coordinate position. In this example, the first inclination angle may be in the azimuth direction toward the suction side, and the second inclination angle may be in the azimuth direction toward the pressure side; or the first inclination angle may be in the azimuth direction toward the pressure side, and the second inclination angle may be in the azimuth direction toward the suction side.

[0088] As an example, the tilt angle may be an average tilt angle. For example, a positive tilt angle may be an average tilt angle, and a negative tilt angle may be an average tilt angle. As an example, a tilt angle such as Fig.15 Such an average tilt angle can be calculated by drawing a straight line between the hub point and the shroud point of the blade, as can be determined by: Fig.15 The hub and shroud sizes are represented in graph 1500 .

[0089] As an example, a turbocharger turbine wheel may include a number of blades that may be selected from a range of 3 blades to 30 blades. For example, consider a turbocharger turbine wheel in which the number of blades is eleven (11).

[0090] As an example, a turbocharger turbine wheel may include radial inlet flow blades (e.g., a radial flow turbine wheel) and / or may include mixed inlet flow blades (e.g., a mixed flow turbine wheel). As for the mixed inlet flow blades, each of the mixed inlet flow blades may be defined in part by a cone angle (e.g., at a leading edge).

[0091] As an example, a turbocharger turbine wheel may include a first tilt angle and a second tilt angle, the first tilt angle and the second tilt angle having opposite signs, as may be defined by radial lines (see, e.g. Fig.15 1500).

[0092] As an example, a turbocharger turbine impeller may include an inclination angle gradient between a first inclination angle and a second inclination angle, wherein the sign of the first inclination angle is opposite to the sign of the second inclination angle. For example, the first inclination angle may be an inclination angle toward one side of the blades of the turbocharger turbine impeller, and the second inclination angle may be an inclination angle toward the opposite side of the blades of the turbocharger turbine impeller. As an example, the inclination angle gradient may pass through a zero inclination angle. As an example, the inclination angle gradient may be defined with respect to the rotation axis of the turbocharger turbine impeller. For example, when moving from the rear wheel disc to the nose along the rotation axis, the inclination angle gradient may change from a negative inclination angle value to a positive inclination angle value, or, for example, from a positive inclination angle value to a negative inclination angle value. As mentioned, the turbocharger turbine impeller may include a non-constant inclination angle of the blades on an axial span in the direction along the rotation axis of the turbocharger turbine impeller. In such an example, the axial span may correspond to an axial distance or a portion of the axial distance from a minimum axial position of the shroud edge to a maximum axial position of the shroud edge.

[0093] As an example, a turbocharger may include a compressor assembly; a center housing assembly operably coupled to the compressor assembly; and a turbine assembly operably coupled to the center housing assembly, wherein the turbine assembly includes a turbine wheel including a hub including an axis of rotation, a rear wheel disk, and a nose, wherein the axis of rotation defines an axial coordinate (z) in a cylindrical coordinate system including a radial coordinate (r) and an azimuthal coordinate (θ) in an intended direction of rotation about the axis of rotation; and blades extending outwardly from the hub, wherein each of the blades includes a shroud edge, a leading edge, a trailing edge, a pressure side, and a suction side, wherein the shroud edge includes a minimum axial coordinate position where the shroud edge intersects the leading edge, and a maximum axial coordinate position where the shroud edge intersects the trailing edge, and wherein, between the minimum axial coordinate position and the maximum axial coordinate position, each of the blades includes a first tilt angle at a first axial coordinate position defined about a first radial line, a second tilt angle at a second axial coordinate position defined about a second radial line, and a tilt angle recurved region at a recurved axial coordinate position between the first axial coordinate position and the second axial coordinate position. In such an example, the tilt angle may provide enhanced performance.For example, consider the enhanced efficiency of an exhaust gas turbine of a turbocharger including a turbine wheel having such blades (eg, individual blades having both positive and negative tilt).

[0094] Although some examples of methods, devices, systems, arrangements, etc. have been shown in the drawings and described in the foregoing detailed description, it should be understood that the disclosed example embodiments are not limiting but are capable of many rearrangements, modifications, and substitutions.

Claims

1. A turbocharger turbine impeller, comprising: a wheel hub comprising an axis of rotation, a rear wheel disc and a nose, wherein the axis of rotation defines an axial coordinate (z) in a cylindrical coordinate system including a radial coordinate (r) and an azimuthal coordinate (θ) in an intended direction of rotation about the axis of rotation; and blades extending outwardly from the hub, wherein each of the blades comprises Shield edge, Front edge, trailing edge, pressure side, and Suction side, The shield edge includes the minimum axial coordinate position where the shroud edge intersects the leading edge, and the maximum axial coordinate position where the shroud edge intersects the trailing edge, and Wherein, between the minimum axial coordinate position and the maximum axial coordinate position, each of the blades includes a first tilt angle defined by a first radial line and a line between a hub edge and a blade shroud edge at a first axial coordinate position, a second tilt angle defined by a second radial line and a line between the hub edge and the blade shroud edge at a second axial coordinate location, and An inclination angle recurved region at a recurved axial coordinate position between the first axial coordinate position and the second axial coordinate position, wherein the first inclination angle and the second inclination angle are in opposite azimuthal directions, wherein the opposite azimuthal directions include an azimuthal direction toward the suction side and an azimuthal direction toward the pressure side.

2. The turbocharger turbine wheel of claim 1, wherein the first inclination angle is in an azimuthal direction toward the suction side, and wherein the second inclination angle is in an azimuthal direction toward the pressure side.

3. The turbocharger turbine wheel of claim 1, wherein the first inclination angle is in an azimuthal direction toward the pressure side, and wherein the second inclination angle is in an azimuthal direction toward the suction side.

4. The turbocharger turbine wheel of claim 1, wherein the first tilt angle is an average tilt angle defined along a line between a hub edge and a blade shroud edge at a first axial coordinate location. 5 . The turbocharger turbine wheel of claim 1 , wherein the second tilt angle is an average tilt angle defined along a line between a hub edge and a blade shroud edge at a second axial coordinate location.

6. The turbocharger turbine wheel of claim 1, wherein the number of blades is selected from the range of 3 blades to 30 blades.

7. The turbocharger turbine wheel of claim 1, wherein the number of blades is eleven.

8. The turbocharger turbine wheel of claim 1, wherein the blades comprise radial inlet flow blades.

9. The turbocharger turbine wheel of claim 1, wherein the blades comprise mixing inlet flow blades.

10. The turbocharger turbine wheel of claim 9, wherein each of said mixing inlet flow vanes includes a cone angle.

11. The turbocharger turbine wheel of claim 1 , wherein the first inclination angle and the second inclination angle comprise opposite signs.

12. The turbocharger turbine wheel of claim 1, wherein the turbocharger turbine wheel comprises an inclination angle gradient between the first inclination angle and the second inclination angle.

13. The turbocharger turbine wheel of claim 12, wherein the pitch angle gradient passes through a zero pitch angle.

14. The turbocharger turbine wheel of claim 12, wherein the tilt angle gradient is defined about the rotation axis.

15. A turbocharger comprising: Compressor components; a center housing assembly operably coupled to the compressor assembly; as well as a turbine assembly operably coupled to the center housing assembly, wherein the turbine assembly includes a turbine wheel including a a wheel hub comprising an axis of rotation, a rear wheel disc and a nose, wherein the axis of rotation defines an axial coordinate (z) in a cylindrical coordinate system comprising a radial coordinate (r) and an azimuthal coordinate (θ) in an intended direction of rotation about the axis of rotation; and blades extending outwardly from the hub, wherein each of the blades comprises Shield edge, Front edge, trailing edge, pressure side, and Suction side, The shield edge includes the minimum axial coordinate position where the shroud edge intersects the leading edge, and the maximum axial coordinate position where the shroud edge intersects the trailing edge, and Wherein, between the minimum axial coordinate position and the maximum axial coordinate position, each of the blades includes a first tilt angle defined by a first radial line and a line between a hub edge and a blade shroud edge at a first axial coordinate position, a second tilt angle defined by a second radial line and a line between the hub edge and the blade shroud edge at a second axial coordinate location, and An inclination angle recurved region at a recurved axial coordinate position between the first axial coordinate position and the second axial coordinate position, wherein the first inclination angle and the second inclination angle are in opposite azimuthal directions, wherein the opposite azimuthal directions include an azimuthal direction toward the suction side and an azimuthal direction toward the pressure side.

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