TURBOCHARGER BEARING HOUSING

Abstract

A turbocharger bearing housing is disclosed. The turbocharger bearing housing comprises a main body that extends radially outward and forms a turbine end. The turbine end is designed with a geometry complementary to a turbine wheel. A passage is designed to extend through the bearing housing to allow fluid communication with the outside of the bearing housing.

Description

CROSS-REFERENCE TO RELATED REGISTRATIONS

[0001] This application claims priority pursuant to 35 USC §119(e) over the preliminary US application No. 63 / 468,973, filed on May 25, 2023; the preliminary US application No. 63 / 522,209, filed on June 21, 2023; and the preliminary US application No. 63 / 649,094, filed on May 17, 2024. Technical field

[0002] The present disclosure relates generally to turbochargers and in particular to bearing components and systems associated with turbochargers. background

[0003] A turbocharger is a device used in internal combustion engines and generators to increase their power output by compressing the incoming air. It functions as a forced intake system, utilizing exhaust gases to drive a turbine, which in turn drives a compressor. Turbochargers harness exhaust energy to force more air into the engine, thus improving its efficiency. The compressor then pressurizes the intake air, allowing more air to enter the engine's cylinders during each intake stroke. By compressing the incoming air, turbochargers enable a higher air-fuel ratio, resulting in increased power output and improved fuel efficiency. Turbochargers are widely used in automotive and industrial applications to enhance engine performance.

[0004] Turbine wheels are used in turbochargers to increase the power and efficiency of internal combustion engines and generators. Mounted on a shaft, turbine wheels rotate at high speed in response to the exhaust flow. The primary function of a turbine wheel is to convert exhaust energy into rotational energy, which is then used to drive the turbocharger's compressor wheel. As exhaust gases move through the turbine housing, they strike the turbine wheel's blades, causing it to spin rapidly. The turbine wheel's rotation drives the compressor wheel at the other end of the shaft, which compresses fresh air and forces it into an engine's intake manifold or a generator's air intake or supply system. This compressed air allows more fuel to be burned, resulting in increased power output.

[0005] Turbine wheels can rotate at speeds on the order of hundreds of thousands of revolutions per minute. Turbine wheels consist of a circular back wall, on one of whose flat surfaces turbine blades are arranged in a uniform circular pattern. To achieve lower inertia and reduced stress along the back wall of the turbine wheel, the back wall can be bulged between the turbine blades. However, conventional shafts lead to efficiency losses in the turbocharger.

[0006] Turbocharger applications present a challenge due to high temperatures and stresses, as turbine wheels are subjected to significant thermal loads. Conventional turbocharger designs incorporate heat shields to minimize heat transfer from the turbine wheel to other components, such as the bearing housing or compressor side. These shields act as thermal barriers between the turbine wheel and other turbocharger parts, reducing heat transfer to sensitive areas like bearings, oil, and cooling systems. By providing a protective layer, heat shields minimize heat transfer, thereby reducing the risk of heat-related damage or deterioration in the performance of surrounding components.

[0007] Others have attempted to provide heat shield solutions between the turbine wheel and the turbocharger, but they have not succeeded in developing a design that allows for simplified assembly and avoids unwanted airflow. For example, US Patent 9,797,409 discloses a turbocharger with a bearing housing integrated into a heat shield. However, this patent reveals a heat shield and bearing housing assembled as separate components, resulting in suboptimal airflow and cooling within the turbocharger. Heat shields present a challenge during assembly and can be cumbersome in the manufacturing process. Because heat shields can be complex and time-consuming to assemble, it would be desirable to find alternatives that offer improved performance and easier installation.

[0008] It is therefore understandable that there is a need for a turbocharger and a bearing housing for engines and generators that ensure sufficient cooling of the engine and generator components, provide improved airflow behavior and are easier to install. Summary of the Revelation

[0009] According to one aspect of the disclosure, a turbocharger bearing housing is disclosed. The turbocharger bearing housing comprises a main body that extends radially outward and forms a turbine end. The turbine end is configured with a geometry complementary to a turbine wheel. A passage is configured to extend through the bearing housing to allow fluid communication with the outside of the bearing housing.

[0010] According to another aspect of the disclosure, a turbocharger system is disclosed. The turbocharger system comprises a bearing housing having a main body extending radially outward and forming a turbine end, the turbine end having a complementary geometry with the turbine wheel; a shaft rotatably mounted in a shaft bore within the bearing housing, the turbine wheel being provided at one end of the shaft near the turbine end; and a passage extending through the bearing housing to allow fluid communication with the outside of the bearing housing.

[0011] According to another aspect of the disclosure, a method for forming a bearing housing for a turbocharger is disclosed. The method comprises casting a bearing housing having a main body with a turbine end extending radially outward toward a turbine wheel, the turbine end having a geometry complementary to the turbine wheel.

[0012] These and other aspects and features of the present disclosure will become more apparent when reading the following detailed description in conjunction with the accompanying drawings. Brief description of the drawings Fig. Figure 1 is a perspective view of a turbocharger according to one embodiment of the disclosure. Fig. 2 is a cross-section of a turbocharger made of Fig. 1 along line 2-2 according to one embodiment of the disclosure. Fig. 3 is a cross-section of the turbocharger made of Fig. 2 in an area around a turbine wheel according to an embodiment of the disclosure. Fig. 4 is a cross-section of the turbocharger made of Fig. 2 in an area around a turbine wheel according to a further embodiment of the disclosure. Fig. 5 is a cross-section of a turbocharger made of Fig. 1 along line 2-2 according to a further embodiment of the disclosure. Fig. 6 is a close-up of a heat shield made of Fig. 5 according to a further embodiment of the disclosure. Fig. Figure 7 is a perspective view of a turbine wheel according to an embodiment of the disclosure. Fig. Figure 8 is a front view of a turbine wheel according to one embodiment of the disclosure. Fig. Figure 9 is a flowchart of a method for forming a bearing housing for a turbocharger according to an embodiment of the disclosure. Fig. Figure 10 is a perspective sectional view of a turbocharger according to an embodiment of the present disclosure. Fig. Figure 11 is a front view of a turbine wheel according to an embodiment of the present disclosure. Fig. Figure 12 is a cross-sectional view of a turbine wheel along line 12-12 in Fig. 11, which is constructed according to the present revelation. Fig. 13 is an enlarged view of Fig. 11, which shows in more detail the turbine wheel constructed according to the present disclosure. Fig. Figure 14 is an enlarged cross-sectional view of Fig. 12, which shows in more detail the turbine wheel constructed according to the present disclosure. Fig. Figure 15 is an enlarged cross-sectional view of Fig. 12, which shows in more detail an alternative embodiment of the turbine wheel constructed according to the present disclosure. Fig. Figure 16 is an enlarged cross-sectional view of Fig. 12, which shows in more detail an alternative embodiment of the turbine wheel constructed according to the present disclosure. Fig. Figure 17 is an enlarged cross-sectional view of Fig. 12, which shows in more detail an alternative embodiment of the turbine wheel constructed according to the present disclosure. Fig. Figure 18 is a perspective view of the turbine wheel constructed according to the present disclosure. Fig. Figure 19 is a cross-sectional view of the turbocharger. Fig. 10 along line 19-19, which is constructed according to the present disclosure. Fig. Figure 20 is a cross-sectional view of the turbocharger. Fig. 19 in an area around a turbine wheel constructed according to the present disclosure. Fig. Figure 21 is a flowchart that represents an example sequence of steps that can be carried out according to a method for manufacturing a turbocharger of the present disclosure. Fig. 22 is a cross-section of a turbocharger made of Fig. 1 according to a further embodiment of the disclosure.

[0013] The figures show one embodiment of the invention presented and serve only for illustration. A person skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated here can be used without deviating from the principles described herein. Detailed description

[0014] Now, referring to the drawings and in particular to the one in Fig. Figure 1 shows a turbocharger 100 for a generator. While the following detailed description describes one exemplary aspect in connection with the turbocharger, it should be noted that the description applies equally to the use of the present disclosure in other applications, including, but not limited to, gasoline-powered generators, diesel-powered generators, charge-air-cooled generators and energy recovery generators, rotary engines, gasoline internal combustion engines and / or diesel engines used in various automobiles, passenger cars, trucks, SUVs, CSUVs, sports cars, racing cars and other similar power generators and vehicles.

[0015] The turbocharger 100 includes a turbine wheel 102, a compressor 104, and a shaft 106 for rotatingly coupling the turbine wheel 102 and the compressor 104. The shaft 106 extends through a bearing housing 108. The turbine wheel 102 can be located within a turbine housing, and the compressor 104 can be located in a compressor cover, as is generally known in the art. The compressor 104 can be a compressor wheel, as is generally known in the art. The shaft 106 can be provided in a shaft bore 110 in the bearing housing 108.

[0016] The turbine wheel 102 can be driven by the exhaust gas exiting the turbocharger 100. The rotation of the turbine wheel 102 is transmitted to the compressor 104 via the shaft 106. The compressor 104 can be used to increase the pressure of intake air before it mixes with fuel for combustion in an engine or generator. The rotation of the turbine wheel 102 creates a forced vortex in which the particle velocity and pressure change proportionally to the radius of rotation.

[0017] Now, referring to the Fig. 2 to 4 is a cross-section of the turbocharger 100 made of Fig. 1 along line 2-2 according to one embodiment of the disclosure. As in Fig. As shown in Figure 2, the shaft 106 can extend through the bearing housing 108 and be rotatably mounted within the bearing housing 108 in the shaft bore 110. The shaft 106 can have a plurality of bearings 112 mounted around it. The plurality of bearings 112 can include plain bearings and / or ball bearings, as are commonly known in engineering. The shaft 106, the turbine wheel 102, and the compressor 104 can rotate at very high speeds, for example, more than 250,000 rpm. To support these high speeds, the plurality of bearings 112 used to support the shaft 106 can be lubricated with oil.

[0018] As in the Fig. As shown in Figures 3-4 in a region around the turbine wheel 102, the bearing housing 108 has a main body 114 extending radially to the turbine wheel 102, with a turbine end 116 having a geometry complementary to that of the turbine wheel 102. The turbine end 116 can be formed in any suitable manner when forming the bearing housing 108, for example by casting, machining, shot peening, and the like. The turbine end 116 extends in a generally radially outward direction relative to an axis of rotation of the shaft 106 taken along line 2-2. The turbine end 116 faces the turbine wheel 102 and is formed according to the geometry of a compressor end 118 of the turbine wheel 102, which faces the compressor 104.

[0019] The components within the bearing housing 108, such as the set of bearings 112, are protected from unwanted heat energy transfer from the exhaust gas to the turbine wheel 102, since the turbine end 116 prevents the conductive and radiative heat flow from the exhaust gas through the bearing housing 108 back to the compressor end 118. By casting the turbine end 116 according to the geometry of the turbine wheel 102, adverse effects from temperature increases within the turbocharger 100 are avoided by preventing heat from reaching the compressor 104 and affecting components within the turbocharger 100. The turbine end 116 also impedes heat flow from the exhaust gas to the sealing rings, piston rings, and the multiple bearings 112. The turbine end 116 of the bearing housing 108 is a heat shield that is formed integrally with the bearing housing 108.

[0020] The turbine end 116 can have various configurations required to be complementary to the geometry of the turbine wheel 102. For example, the bearing housing 108 can have a generally disc-shaped, unflanged structure. When the turbine end 116 is complementary to the turbine wheel 102, the complementary geometry allows for a uniform tolerance sum, thereby eliminating undesirable air gaps that lead to unwanted air circulation and air accumulation within the turbocharger 100. The turbine end 116 can be designed with a complementary geometry to form an outlet air gap 200 from the tolerance sum formed after assembly between the turbine end 116 and the turbine wheel 102, in order to promote an exhaust airflow that cools the turbine wheel 102 and exits the turbocharger 100.The outlet air gap 200 allows the active supply of cooling air between the turbine wheel 102 and the turbine end 116, thus eliminating the need for a separate heat shield attached to the bearing housing 108. The turbine end 116 is machined or cast, with its complementary geometry controlled to manage the tolerance and the gap between the turbine end 116 and the turbine wheel 102. By controlling the tolerance clearance between the turbine end 116 and the turbine wheel 102, cooling air is allowed in the outlet air gap 200, eliminating the need to couple a separate heat shield to the bearing housing 108. The cooling air actively present in the outlet air gap 200 acts as a heat shield, improving the cooling of the turbine wheel 102 and further eliminating the need for a separate heat shield to be coupled to the bearing housing 108.

[0021] The turbine end 116 can be at least partially covered with a heat-insulating material, for example, ceramic fibers, heat-resistant fabrics, metal foils, composites, and thermal barrier coatings (TBCs). The heat-insulating material can include, for example, metal matrix composites such as aluminum matrix composites, titanium diboride, aluminum oxide, aluminum oxide-silicon dioxide, boron nitride, silicon carbide, vitrified silica, YSZ (yttrium-stabilized zirconia), gadolinium zirconate, MCrAY coatings, plasma-sprayed TBCs, TBCs with electron beam physical vapor deposition (EB-PVD), and zirconia.

[0022] The oil used to lubricate the numerous bearings 112 can also be susceptible to decomposition and coking if the operating temperatures inside the turbocharger 100 become too extreme. The turbocharger 100 can utilize the bearing housing 108 to prevent heat from the exhaust gas from flowing within the bearing housing 108 from the turbine wheel 102 to the compressor 104. The exhaust gas temperature in an engine or generator can range between 740 °C and 1050 °C, depending on the fuel used, such as gasoline, diesel, ethanol, and the like.

[0023] With reference to Fig. Figure 4 illustrates an airflow 202 exiting the bearing housing 108, according to one embodiment of the disclosure. By extending the bearing housing 108 to the turbine end 116 and adapting the turbine end 116 to the geometry of the turbine wheel 102, suboptimal airflows are prevented and avoided, since the tolerance sum resulting after assembly between the bearing housing 108 and the turbine wheel 102 causes fewer air gaps and / or air accumulations. By extending the bearing housing 108 to the turbine end 116 and shaping the turbine end 116 to the geometry of the turbine wheel 102, the airflow 202 can exit the turbocharger 100 with a more uniform flow, which can provide improved cooling of the turbine wheel 102.The airflow 202 can be high-pressure air, acting as a sealant that prevents oil from escaping from the bearing housing 108, while simultaneously providing cooling air for the turbine wheel 102 and the turbine end 116. The cooling air from the airflow 202 in the outlet air gap 200 acts as a heat shield.

[0024] The airflow 202 in the bearing housing 108 of the turbocharger 100 is generated by a combination of natural and forced convection. Natural convection occurs when heated air rises and creates a flow within at least one passage 204 in the bearing housing 108. The at least one passage 204 can be provided in the bearing housing 108 to allow fluid to connect with the outlet air gap 200 for exiting the turbocharger 100. The at least one passage 204 serves as the outlet path from the bearing housing 108 to the outlet air gap 200.

[0025] In one embodiment, the at least one passage 204 can be distributed in any suitable manner, for example, as evenly or unevenly spaced circumferential slots. The at least one passage 204 can extend through the turbine end 116 or through a section of the bearing housing 108. The at least one passage 204 can have various orientations, parallel, perpendicular, or at any suitable angle relative to the axis of the shaft 106, shown by line 2-2. The at least one passage 204 can be optimized in several radial positions to achieve ideal pressure conditions. The at least one passage 204 can be formed by casting and / or machining.

[0026] The airflow 202, directed to the turbine wheel 102 through at least one passage 204, can be recirculated in a chamber 206 within the bearing housing 108. The chamber 206 can be formed during the casting or machining of the bearing housing 108. The exhaust gas flow 202 can enter the chamber 206 and flow towards at least one passage 204 and / or the outlet air gap 200, where it exits the chamber 206. The recirculation of the exhaust gas within the chamber 206 can facilitate the airflow, the eddy current, and / or the pressure within the bearing housing 108, resulting in an increased outlet flow. The pressure increase can facilitate the airflow between the turbine end 116 and the turbine wheel 102, thereby cooling the turbine wheel 102.

[0027] Now, referring to Fig. Figure 5 illustrates a cross-sectional view of the turbocharger 100 according to a further embodiment of the disclosure. Fig. Figure 5 shows the turbine wheel 102 as in Fig. Figure 2 shows, but with design modifications according to a further embodiment of the disclosure. This embodiment illustrates a modified cooling system in which one transverse bore of each supply path is omitted. A heat shield 500 is arranged on the main body 114 of the bearing housing 108 by means of a fastening means, for example, a screw 502. The main function of the heat shield 500 is to block the outlets of the axial supply path and thereby pressurize the area behind the heat shield 500. This configuration directs the cooling airflow around the inner tip 506 of the heat shield 500, thus ensuring a uniform distribution of the cooling air over the rear wall of the turbine wheel 102, originating from the outer diameter of the shaft 106.

[0028] The heat shield 500 acts as a barrier to protect against direct heat transfer and as a conduit to effectively direct cooling air around its circumference. Design considerations for the heat shield 500 include its material composition, which can withstand high thermal loads, and its geometric alignment with the turbine wheel 102 to facilitate optimal airflow.

[0029] The screw 502, used to secure the heat shield 500 to the bearing housing 108, is designed for robust mounting and ensures the stability of the heat shield 500 during operation. The choice of material for the screw 502 and the design of its thread are crucial for maintaining the structural integrity of the assembly under high torque and thermal expansion.

[0030] With reference to the Fig. 5 and Fig. 22 A labyrinth seal 510 and / or a ring seal 512 are provided to improve the sealing effect between the shaft and the bore near the first end of the bearing housing. The labyrinth seal 510, positioned between the shaft and the bore, incorporates several profiles arranged in a series of stages to create a winding path for the air. This design minimizes air loss and improves the sealing effect. The labyrinth seal 510 is strategically placed in the high-pressure stage of the turbine, where it effectively regulates the pressure differential between the first volume 514 and the second volume 516. By employing multiple profiles, the labyrinth seal 510 ensures that any air attempting to bypass the seal is throttled and distributed across each stage, thereby significantly reducing overall leakage.

[0031] The ring seal 512, often also referred to as a piston ring seal, is used in the low-pressure stage of the turbine. This seal comprises one or two piston rings that form an additional sealing mechanism between the shaft and the bore. The ring seal 512 is designed for lower pressure differentials and complements the function of the labyrinth seal 510 by forming a first barrier against air leakage. Located further downstream in the sealing assembly, the ring seal 512 ensures that any residual air flowing past the labyrinth seal 510 is effectively sealed.

[0032] The combination of labyrinth seal 510 and ring seal 512 forms a robust sealing system for the radial turbine. The high-pressure stage, regulated by the labyrinth seal 510, ensures minimal air leakage by creating multiple barriers that the air must pass through. The downstream ring seal 512 acts as a secondary sealing mechanism, providing additional protection against any air that might bypass the labyrinth seal 510. This dual-seal approach ensures optimal turbine performance by maintaining the required pressure differentials between the first volume 514 and the second volume 516.

[0033] During operation, air from the first volume 514 is diverted around the heat shield and away from the labyrinth seal 510, minimizing the amount of air passing through the seal and ensuring efficient sealing. The bearing housing design with a rounded edge at the first end further contributes to diverting air away from the sealing elements, thus improving the durability and efficiency of both the labyrinth seal 510 and the ring seal 512.

[0034] By employing these advanced sealing technologies, the radial turbine ensures improved operating performance, reduced air leakage and increased service life of the sealing components, contributing to the overall efficiency and reliability of the turbocharger system.

[0035] The main body of the bearing housing 108 is fitted with the heat shield 500, which comprises a section located between the main body of the bearing housing 108 and the turbine wheel 102. The heat shield 500 has an opening that is coaxial with the shaft bore 110, allowing a section of the shaft 106 to pass through it. The heat shield 500 defines a first chamber 514 between the bearing housing 108 and the heat shield 102 and a second chamber 516 between the heat shield 500 and the turbine wheel 102. The first chamber 514 and the second chamber 516 are in fluid communication via a radial gap 124 between a section of the heat shield 500 and the shaft 106. The bearing housing 122 includes at least one cooling channel 508, which acts as at least one air passage connected to the first chamber 514.During operation, air flows from the at least one cooling channel 508 into the first volume 514 and then into the second volume 516. The air passage may have a widened section 128 near the heat shield 500, where the cross-sectional area increases to a maximum.

[0036] A first end of the bearing housing 108 can have a recessed section located radially outside the shaft bore 110 and inside the cooling channel 508. This recessed section has a curved profile, causing the axial dimension of the bearing housing 108 to increase towards the turbine wheel 102 with decreasing radial distances. Additionally, a first section of the bearing housing 108 has a rounded cross-sectional profile at the opening 120. The heat shield 500 includes a first surface facing the first volume 514 and a second surface facing the second volume 516, with the rounded cross-sectional profile of the inner tip 506 defining a semicircular cross-section connecting the first and second surfaces of the heat shield 500. Now, referring to Fig. Figure 22 shows interface 504, the overlapping area where shaft 104 and turbine wheel 102 meet. Interface 504 is designed with a friction fit, ensuring a secure connection. The parts are friction welded, creating a strong, reliable connection that withstands high rotational speeds and significant forces during operation. The friction fit and friction welding ensure that no relative movement occurs between the shaft and turbine wheel, thus maintaining alignment and extending the system's service life.

[0037] Now, referring to Fig. Figure 6 shows a close-up of the inner tip 506 according to a further embodiment of the disclosure. The inner tip 506 of the heat shield 500 is specifically shaped to guide the cooling air with minimal resistance and to promote an efficient flow path around the heat shield 500 and to the cooling channels 508. The shape of the inner tip 506 was designed to ensure a smooth transition of the airflow, thereby reducing turbulence and improving cooling performance.

[0038] The cooling channels 508 are designed to distribute cooling air evenly across the rear wall of the turbine wheel 102. The configuration and orientation of these channels are crucial for achieving a uniform temperature gradient across the turbine wheel 102, thereby mitigating overheating zones and improving the component's service life.

[0039] Now, referring to the Fig. Figures 7-8 illustrate the turbine wheel 102 according to one embodiment of the disclosure. Fig. 7 and Fig. Figure 8 shows the general shape of the turbine wheel 102, illustrating its aerodynamic profile, which is designed to efficiently convert the energy of the exhaust gases into rotational energy. The turbine wheel 102 can include multiple blades, each designed to maximize the conversion of thermal and kinetic energy from the exhaust gases into mechanical energy. The geometric design of the turbine wheel 102, including the curvature and angle of the blades, is optimized for operation under a wide range of operating conditions, ensuring a balanced ratio between efficiency and durability.

[0040] While the following detailed description describes one exemplary aspect in connection with the turbocharger, it should be noted that the description applies equally to the use of the present disclosure in other applications, including, but not limited to, gasoline-powered generators, diesel-powered generators, charge-air-cooled generators and energy recovery generators, rotary engines, gasoline internal combustion engines and / or diesel engines used in various automobiles, passenger cars, trucks, SUVs, CSUVs, sports cars, racing cars and other similar power generators and vehicles.

[0041] In another embodiment, as in Fig. As shown in Figure 10, a turbocharger 1100 includes a turbine wheel 1102, a compressor wheel 1104, and a shaft 1106 for rotatably coupling the turbine wheel 1102 and the compressor wheel 1104. The shaft 1106 extends through a central housing 1108. The turbine wheel 1102 can be located within a turbine housing, and the compressor wheel 1104 can be located within a compressor housing, as is generally known in the art. The shaft 1106 can be provided in a shaft bore 1110 in the central housing 1108.

[0042] The turbine wheel 1102 can be driven by the exhaust gas exiting the turbocharger 1100. The rotation of the turbine wheel 1102 is transmitted via the shaft 1106 to the compressor wheel 1104. The compressor wheel 1104 can be used to increase the pressure of intake air before the air mixes with fuel for combustion in an engine or generator. The rotation of the turbine wheel 1102 creates a forced vortex in which the particle velocity and pressure change proportionally to the radius of rotation.

[0043] An embodiment of the turbine wheel 1102 is shown in Fig. 11 schematically in a front view and in Fig. 12 shown schematically in a sectional view, which follows line 12-12 from Fig. 11 corresponds. The turbine wheel 1102 can be formed by a casting process and attached at one end to the shaft 1106 via a shaft mounting area 1204. The turbine wheel 1102 can form a turbine wheel body 1202 with a back wall 1206 at the end of the turbine wheel body 1202 near the shaft mounting area 1204. As shown in the Fig. As shown in Figures 12-13, the rear wall 1206 of the turbine wheel 1102 is designed as a disk with a rear wall end thickness t1. The turbine wheel 1102 can include a plurality of blades 1208 which interact with the exhaust gases of an engine and drive the rotation of the shaft.

[0044] Fig. Figure 13 illustrates details of the turbine wheel 1102. Each of the plurality of blades 1208 can have a blade width 1210, which represents the spacing between the plurality of blades 1208. The blade width 1210 can be constant, so that the plurality of blades 1208 is evenly distributed over the surface of the back wall 1206, or the blade width 1210 can vary among the plurality of blades 1208. Since the turbine wheel 1102 is cast, the back wall 1206 and the plurality of blades 1208 can have a cast surface 1212 with a cast diameter 1214. The turbine wheel 1102 is located in an area with narrow gaps.The casting tolerances can be high. To create a uniform surface, provide clearance to the turbine wheel 1102, and ensure balance and a surface with minimal air resistance, the cast surface 1212 can be ground to a machined surface 1216 with a constant diameter, represented by a machined diameter 1218. As a result of grinding the multitude of blades 1208, a blade area can be formed on each of the multitude of blades 1208, represented by the machined surface 1216, with a blade diameter corresponding to the machined diameter 1218.

[0045] During the casting process, bulges can be formed in the rear wall 1206 of the turbine wheel 1102, which in Fig. 13 are represented by a bulge area 1220. To provide a smooth transition between the bulge area 1220 and the blade area formed by the machined surface 1216, a transition area 1224 can also be provided by the casting process at each end of the bulge area 1220, where it transitions back into the blades of the plurality of blades 1208. The transition area can include a progressive rounding from the bulge area 1220 into the plurality of blades 1208. The transition area 1224 can further include the casting of a section of the plurality of blades with a transition radius 1226, which is formed tangentially to the bulge area 1220 at the bulge diameter 1222. Fig. Figure 19 shows the fully machined turbine wheel 1102 with the blade area formed by the machined surface 1216, the bulge area 1220 and the transition area 1224, which connects the two.

[0046] The bulge area 1220 can have a constant diameter from the center of the turbine wheel 1102, represented by a bulge diameter 1222. The bulge diameter 1222 can be nominally smaller than the machined diameter 1218, so that the bulge area 1220 forms "mini-bulges" in contrast to conventional bulges.

[0047] For example, the diameter of the bulge 1222 can be between 98% and 99.6% of the machined diameter 1218. Other percentages are certainly possible. In another example, the bulge diameter 1222 can be nominally smaller than the machined diameter 1218 due to predetermined tolerances in the casting process. In this example, the machined diameter 1218 is predetermined, and an upper limit for the casting tolerance is set such that the bulge diameter 1222 is always smaller than the machined diameter.

[0048] The bulge area 1220 can be rounded with various profiles, so that several different embodiments of the turbine wheel 1102 can be formed. In a Fig. In the primary embodiment shown in Figure 14, the bulge area 1220 can be completely rounded, wherein the profile of the bulge area 1220 has a diameter corresponding to that of the back wall end thickness t1. The rounding of the bulge area 1220 can have tangential transitions to both surfaces of the back wall 1206. In a second embodiment, which is further described by Fig. As shown in Figure 15, the bulge area 1220 can have a bulge profile with an elliptical profile that includes tangential transitions to both surfaces of the rear wall 1206. In a third embodiment, which is described by Fig. As shown in Figure 16, the bulge area 1220 can have a three-part bulge profile. The profile of the bulge area 1220 in Fig. 16 can have a flat section at the bulge diameter 1222, located on or near the machined surface 1216, as well as rounded sections at each end of the flat section, which have a radius and form tangential transitions into the flap section and the front and back of the rear wall 1206. Finally, in an alternative embodiment, which is further described by Fig. As shown in Figure 17, the bulge profile is defined by a freestyle curve 1228. Other embodiments of the bulge area 1220 with different bulge profiles can also be implemented.

[0049] Now, referring to the Fig. 19 to 20 is a cross-section of the turbocharger 1100 made of Fig. 10 along line 19-19 according to one embodiment of the disclosure. As illustrated in Fig. As shown in Figure 19, the shaft 1106 can extend through the central housing 1108 and be rotatably mounted within the central housing 1108 in the shaft bore 1110. The shaft 1106 can have a plurality of bearings 1112 mounted around it. The plurality of bearings 1112 can include plain bearings and / or ball bearings, as are commonly known in engineering. The shaft 1106, the turbine wheel 1102, and the compressor wheel 1104 can rotate at very high speeds, for example, more than 250,000 rpm. To support these high speeds, the plurality of bearings 1112 used to support the shaft 1106 can be lubricated with oil.

[0050] As in the Fig. As shown in Figures 12-13 in a region around the turbine wheel 1102, the central casing 1108 has a main body 1114 extending radially to the turbine wheel 1102, with a turbine end 1116 having a geometry complementary to the turbine wheel 1102. The turbine end 1116 can be formed in any suitable way when forming the central casing 1108, for example by casting, machining, shot peening, and the like. The turbine end 1116 extends in a generally radially outward direction relative to an axis of rotation of the shaft 1106 taken along line 20-20. The turbine end 1116 faces the turbine wheel 1102 and is formed according to the geometry of a compressor end 1118 of the turbine wheel 1102, which faces the compressor wheel 1104.

[0051] The components within the central housing 1108, such as the numerous bearings 1112, are protected from unwanted heat energy transfer from the exhaust gas to the turbine wheel 1102, since the turbine end 1116 prevents the conductive and radiative heat flow from the exhaust gas through the central housing 1108 back to the compressor end 1118. By casting the turbine end 1116 according to the geometry of the turbine wheel 1102, adverse effects from temperature increases within the turbocharger 1100 are avoided by preventing heat from reaching the compressor 1104 and affecting components within the turbocharger 1100. The turbine end 1116 also impedes the heat flow from the exhaust gas to the sealing rings, piston rings and the multitude of bearings 1112. The turbine end 1116 of the central housing 1108 is a heat shield that is formed integrally with the central housing 1108.

[0052] The turbine end 1116 can have various configurations required to be complementary to the geometry of the turbine wheel 1102. For example, the center casing 1108 can have a generally disc-shaped, flangeless structure. When the turbine end 1116 is complementary to the turbine wheel 1102, the complementary geometry allows for a uniform tolerance sum, thereby eliminating unwanted air gaps that lead to undesirable air circulation and air accumulation within the turbocharger 1100.

[0053] The turbine end 1116 can be at least partially covered with a heat-insulating material, for example, ceramic fibers, heat-resistant fabrics, metal foils, composites, and thermal barrier coatings (TBCs). The heat-insulating material can include, for example, metal matrix composites such as aluminum matrix composites, titanium diboride, aluminum oxide, aluminum oxide-silicon dioxide, boron nitride, silicon carbide, vitrified silica, YSZ (yttrium-stabilized zirconia), gadolinium zirconate, MCrAY coatings, plasma-sprayed TBCs, TBCs with electron beam physical vapor deposition (EB-PVD), and zirconia.

[0054] The oil used to lubricate the numerous bearings 1112 can also be susceptible to decomposition and coking if the operating temperatures inside the turbocharger 1100 become too extreme. The turbocharger 1100 can utilize the center housing 1108 to prevent heat from the exhaust gas from flowing within the center housing 1108 from the turbine wheel 1102 to the compressor wheel 1104. The exhaust gas temperature in an engine or generator can range from 740 °C to 1050 °C, depending on the fuel used, such as gasoline, diesel, ethanol, and the like.

[0055] The turbine end 1116 can be designed with a complementary geometry to form an outlet air gap 1300 (not shown) from the tolerance sum formed after assembly between the turbine end 1116 and the turbine wheel 1102, in order to promote an exhaust air flow that cools the turbine wheel 1102 and exits the turbocharger 1100. The outlet air gap 1300 enables the active supply of cooling air between the turbine wheel 1102 and the turbine end 1116, thus eliminating the need for a separate heat shield attached to the central housing 1108. The turbine end 1116 is machined or cast, with the complementary geometry controlled to manage the tolerance and the gap between the turbine end 1116 and the turbine wheel 1102.By controlling the tolerance gap between the turbine end 1116 and the turbine wheel 1102, cooling air is allowed in the outlet air gap 1300, thus eliminating the need to couple a separate heat shield with the turbocharger 1100. The cooling air actively present in the outlet air gap 1300 acts as a heat shield, improving the cooling of the turbine wheel 1102 and thus also eliminating the need to couple a separate heat shield with the center housing 1108.

[0056] With reference to Fig. Figure 20 illustrates an airflow 1302 exiting the central housing 1108, as described in one embodiment of the disclosure. Extending the central housing 1108 to the turbine end 1116 and adapting the turbine end 1116 to the geometry of the turbine wheel 1102 prevents and avoids suboptimal airflows, since the tolerance sum resulting after assembly between the central housing 1108 and the turbine wheel 1102 causes fewer air gaps and / or air accumulations. Extending the central housing 1108 to the turbine end 1116 and adapting the turbine end 1116 to the geometry of the turbine wheel 1102 allows the airflow 1302 to exit the turbocharger 1100 with a more uniform flow, which can provide improved cooling of the turbine wheel 1102.The airflow 1302 can be high-pressure air acting as a sealant, preventing oil from escaping the central housing 1108, while simultaneously providing cooling air for the turbine wheel 1102 and the turbine end 1116. The cooling air from the airflow 1302 in the outlet air gap 1300 acts as a heat shield.

[0057] The airflow 1302 in the central housing 1108 of the turbocharger 1100 is generated by a combination of natural and forced convection. Natural convection occurs when heated air rises and creates a flow within at least one passage 1304 in the central housing 1108. The at least one passage 1304 can be provided in the central housing 1108 to provide a fluid connection with the outlet air gap 1300 for exiting the turbocharger 1100. The at least one passage 1304 serves as the outlet path from the central housing 1108 to the outlet air gap 1300.

[0058] As in Fig. As shown in Figure 20, the airflow 1302 can be directed behind the turbine wheel 1102 and upwards along a rear side of the back wall 1206. The airflow 1302 can be guided over the rounded profile of the bulge area 1220 between the plurality of blades 1208. The airflow 1302 can then be directed onto the turbine wheel body 1202 of the turbine wheel 1102 and contribute to enhanced cooling of the turbine wheel 1102.

[0059] In one embodiment, the at least one passage 1304 can be distributed in any suitable manner, for example, as evenly or unevenly spaced circumferential slots. The at least one passage 1304 can extend through the turbine end 1116 or through a section of the central casing 1108. The at least one passage 1304 can have various orientations, parallel, perpendicular, or at any suitable angle relative to the axis of the shaft 1106, shown by line 20-20. The at least one passage 1304 can be optimized in several radial positions to achieve ideal pressure conditions. The at least one passage 1304 can be formed by casting and / or machining.

[0060] The airflow 1302, directed through the at least one passage 1304 to the turbine wheel 1102, can be recirculated in a chamber 1306 within the central housing 1108. The chamber 1306 can be formed during the casting or machining of the central housing 1108. The exhaust gas flow 1302 can enter the chamber 1306 and flow towards the at least one passage 1304 and / or the outlet air gap 1200, where it exits the chamber 1306. The recirculation of the exhaust gas within the chamber 1306 can facilitate the airflow, the eddy current, and / or the pressure within the central housing 1108, resulting in an increased outlet flow. The pressure increase can facilitate the airflow between the turbine end 1116 and the turbine wheel 1102, thereby cooling the turbine wheel 1102. Industrial applicability

[0061] In practice, the present disclosure can be applied in many industries, including power generation, energy, the automotive industry, and motorsports. In particular, the technology of the present disclosure can be used for power generators and / or internal combustion engines of motor vehicles, including, but not limited to, power generators, gasoline-powered generators, diesel-powered generators, charge-air-cooled generators, energy recovery generators, gasoline engines, diesel engines, rotary engines, motors, and the like.Although the above detailed description specifically relates to generators for internal combustion engines in motor vehicles, it is understood that its teachings can also be applied to other engines and drives, for example in generators, motor vehicles, cars, trucks, SUVs, CSUVs, sports cars, racing cars and other similar vehicles and machines, as well as other machines with air intake or air supply systems that use a turbocharger.

[0062] Now, referring to Fig. Figure 9 illustrates a method for forming a bearing housing 900 for a turbocharger according to an embodiment of the disclosure. In step 902, the bearing housing 108 is cast, having a main body with a turbine end 116 extending radially outward toward the turbine wheel 102. The turbine end 116 has a geometry complementary to the turbine wheel 102.

[0063] In step 904, at least one passage 204 is formed in the bearing housing 108 to allow fluid outside the bearing housing 108, thereby forming the outlet air gap 200 between the turbine end 116 and the turbine wheel 102.

[0064] The Turbocharger 100 can be installed in a power generator that uses two Turbochargers 100 in series with a power turbine stage, which may operate without a compressor 104 or a compressor stage. The power turbine stage can be directly connected to an AC generator or generator for power generation. When installed in a power generator, generator burners can feed exhaust gases directly to the Turbocharger 100. The power generator can be an intercooler with energy recovery, using two Turbochargers 100 in series with the power turbine stage.

[0065] Now, referring to Fig. Figure 21 illustrates a method for manufacturing the turbine wheel 1102 of the present disclosure. In a first step 1402, the turbine wheel 1102 is cast as a turbine wheel body 1202, which has the shaft mounting area 1204, the back wall 1206, and the plurality of blades 1208 extending from the turbine wheel body to the casting surface 1216 with a casting diameter 1214. The casting process forms the bulge area 1220 between each of the plurality of blades 1208 with a profile defined by the Fig.Figures 14-17 show a resulting constant diameter represented by the bulge diameter 1222. The casting process also forms the transition zone 1224 between the bulge zone 1220 and the plurality of blades 1208. The transition zone 1224 is tangential to the bulge diameter 1222 and has a transition radius 1226 into the plurality of blades 1208.

[0066] In a final step 1404, the cast surface 1212 is machined on the plurality of blades 1208 by grinding the plurality of blades 1208 down to the machined surface 1216 with the machined diameter 1218. The plurality of blades 1208 retains the machined diameter 1218 and thus forms a blade area, the machined diameter 1218 being larger than the bulge diameter 1222.

[0067] The turbine wheel 1102 offers several advantages over conventional turbine wheels. The bulge area 1220 of the turbine wheel 1102 allows for lower rotational inertia and reduced stresses in the back wall 1206, and is so small that only minimal to no efficiency losses occur. Furthermore, the rounding of the back wall 1206, including the bulge area 1220, allows for a greater airflow from the rear of the turbine wheel 1102 into the exhaust path, which interacts with the plurality of blades 1208. A cooling airflow directed so that it flows over the rounded areas of the bulge into the spaces between the plurality of blades 1208 and the turbine wheel body 1202 can promote enhanced cooling of the turbine wheel 1102. The turbine wheel 1102, which has a cooling system, enables the turbocharger 1100 to operate at higher exhaust gas temperatures.

[0068] It is evident from the foregoing that the technology disclosed herein is industrially applicable in a wide variety of fields, for example, but not limited to turbochargers and bearing housings for engines and generators, as well as cooling system designs for turbochargers. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 468.973

[0001] US 63 / 522,209

[0001] US 63 / 649,094

[0001] US 9,797,409

[0007]

Claims

[1] Radial turbine, comprising: a radial turbine wheel attached to a shaft; a main body comprising a first end and an opposite second end, wherein the main body includes a bore extending between the first end and the second end, the bore including bearings configured to support the shaft, with at least one section of the shaft being arranged in the bore and wherein the turbine wheel is located near the first end of the main body; a heat shield attached to the main body, wherein the heat shield includes a section arranged between the first end of the main body and the turbine wheel, wherein the heat shield includes an opening coaxial to the bore of the main body such that a section of the shaft is received in the opening, wherein a first volume is defined between the first end of the bearing housing and the section of the heat shield and a second volume is defined between the section of the heat shield and the turbine wheel, and wherein the first volume and the second volume are in fluid communication via a radial gap between the section of the heat shield and the shaft; at least one air passage arranged in the bearing housing, wherein the at least one air passage terminates at the first end of the bearing housing and is connected to the first volume, wherein during operation air flows from the at least one air passage into the first volume and then into the second volume. [2] Radial turbine according to claim 1, wherein a surface of the section of the heat shield facing the second volume has a cross-sectional shape that is complementary to a cross-sectional shape of a rear wall of the turbine wheel. [3] Radial turbine according to claim 1, further comprising a turbine wheel body having a back wall near a shaft, which is designed as a circular disk having a back wall thickness; a plurality of blades formed in the turbine wheel body; a blade area in which each of the plurality of blades extends from the rear wall and which has a blade diameter measured from the center of the turbine wheel body; a bulge area in the back wall, which is formed as a rounded surface in a radially outermost surface of the back wall and has a bulge diameter dimensioned such that the bulge diameter is as close as possible to the blade diameter while lying radially within a grinding or milling tool that defines the blade diameter; and a transition area from the bulge area to the blade area, wherein the transition area is tangential to the bulge diameter and has a transition radius. [4] Radial turbine according to claim 1, wherein the at least one air passage includes a widened section near the first end of the bearing housing, wherein the cross-sectional area of ​​the air passage increases to a maximum cross-sectional area at the first end of the bearing housing. [5] Radial turbine according to claim 1, wherein the first section of the bearing housing includes a rounded cross-sectional profile at the opening. [6] Radial turbine according to claim 5, wherein the section of the heat shield includes a first surface facing the first volume and a second surface facing the second volume, and wherein the rounded cross-sectional profile defines a semicircular cross-sectional profile connecting the first surface and the second surface. [7] Radial turbine according to claim 1, wherein the first end of the bearing housing includes a recessed section which is arranged radially outside the bore and radially inside the at least one air passage, wherein the recessed section includes a curved profile such that an axial dimension of the bearing housing increases in the direction of the turbine wheel with decreasing radial distances. [8] Radial turbine according to claim 7, wherein the first section of the bearing housing includes a rounded cross-sectional profile at the opening, wherein the section of the heat shield includes a first surface facing the first volume and a second surface facing the second volume, and wherein the rounded cross-sectional profile defines a semicircular cross-sectional profile connecting the first surface and the second surface. [9] Radial turbine according to claim 1, further comprising a seal arranged between the shaft and the bore near the first end of the bearing housing. [10] Radial turbine according to claim 9, wherein the seal is at least one selected from the group consisting of a labyrinth seal and a piston ring. [11] Radial turbine according to claim 1, wherein the turbine end is covered with a thermal barrier layer made of a heat-insulating material, wherein the heat-insulating material is selected from a metal matrix composite, an aluminum matrix composite, a titanium diboride, an aluminum oxide, an aluminum oxide-silicon dioxide, a boron nitride, a silicon carbide, a vitrium oxide, a yttrium-stabilized zirconia, a gadolinium zirconate, MCrAlY coatings, a plasma-sprayed thermal barrier layer, a thermal barrier coating by physical vapor deposition with electron beam (EB-PVD) and a zirconia. [12] Turbocharger system, comprising: a bearing housing comprising a radially outward extending main body forming a turbine end, the turbine end having a geometry complementary to a turbine wheel; a shaft which is rotatably mounted in a shaft bore within the bearing housing, wherein the turbine wheel is provided at one end of the shaft near the turbine end; at least one air passage extending through the bearing housing to allow fluid communication with the outside of the bearing housing; and a heat shield attached to the turbine end, wherein the heat shield includes a section arranged between the turbine end and the turbine wheel, and a first volume is defined between the turbine end and the heat shield, and a second volume is defined between the heat shield and the turbine wheel, wherein the first volume and the second volume are in fluid communication via a radial gap between the heat shield and the shaft. [13] Turbocharger system according to claim 12, comprising at least one air passage arranged in the bearing housing, wherein the at least one air passage terminates at the first end of the bearing housing and is connected to the first volume, wherein during operation air flows from the at least one air passage into the first volume and then into the second volume. [14] Turbocharger system according to claim 13, wherein a surface of the section of the heat shield facing the second volume has a cross-sectional shape that is complementary to a cross-sectional shape of a rear wall of the turbine wheel; the at least one air passage includes a widened section near the first end of the bearing housing, with the cross-sectional area of ​​the air passage increasing to a maximum cross-sectional area at the first end of the bearing housing; the first section of the bearing housing includes a rounded cross-sectional profile at the opening and the first end of the bearing housing includes a recessed section that is arranged radially outside the bore and radially inside the at least one air passage, wherein the recessed section includes a curved profile such that an axial dimension of the bearing housing increases in the direction of the turbine wheel with decreasing radial distances. [15] Turbocharger system according to claim 9, wherein the passage is selected from one of the following: The passage is a continuous slot; one passage extends perpendicular to an axis of the shaft in the bearing housing and The passage extends parallel to an axis of the shaft in the bearing housing. [16] Turbocharger system according to claim 12, further comprising a seal arranged between the shaft and the bore near the first end of the bearing housing. [17] Method for forming a bearing housing for a turbocharger, the method comprising: Casting of the bearing housing, which has a main body with a turbine end extending radially outwards in the direction of a turbine wheel, wherein the turbine end has a geometry complementary to the turbine wheel; Attaching a heat shield to the bearing housing, wherein the heat shield includes a section arranged between the turbine end of the bearing housing and the turbine wheel, wherein the heat shield includes an opening that is coaxial with the bore of the bearing housing, such that a section of the shaft is received in the opening; and Forming at least one air passage in the bearing housing, wherein the at least one air passage terminates at the turbine end of the bearing housing and is connected to a first volume defined between the turbine end of the bearing housing and the heat shield, and to a second volume defined between the heat shield and the turbine wheel, and wherein during operation air flows from the at least one air passage into the first volume and then into the second volume. [18] The method of claim 15, which further includes: Formation of the first volume and the second volume in fluid connection via a radial gap between the section of the heat shield and the shaft. [19] The method of claim 15, which further includes: Forming a widened section in at least one air passage near the turbine end of the bearing housing, wherein the cross-sectional area of ​​the air passage increases to a maximum cross-sectional area at the turbine end of the bearing housing; Forming a recessed section in the turbine end of the bearing housing, which is arranged radially outside the bore and radially inside the at least one air passage, wherein the recessed section includes a curved profile such that an axial dimension of the bearing housing increases towards the turbine wheel with decreasing radial distances; and Forming the heat shield with a first surface facing the first volume and a second surface facing the second volume, wherein the first surface has a cross-sectional shape that is complementary to a cross-sectional shape of a rear wall of the turbine wheel. [20] Method according to claim 16, further comprising forming a seal arranged between the shaft and the bore near the turbine end of the bearing housing, wherein the seal is at least a seal selected from the group consisting of a labyrinth seal and a piston ring.

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