Turbocharger heat shield

Abstract

This invention relates to turbocharger thermal shielding. Methods and systems for turbochargers are provided. In one example, the turbocharger includes a turbine rotor mounted on a shaft and supported within a turbocharger housing; an oil seal disposed within the turbocharger housing; and a thermal shield located near the oil seal within the turbocharger housing, the thermal shield having a hole through which the shaft extends, wherein the thermal shield is configured to sufficiently maintain the position of the oil seal in the event of turbocharger failure.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to UK Patent Application No. 1721048.5, filed on December 15, 2017. For all purposes, the entire contents of the above-mentioned application are incorporated herein by reference. Technical Field

[0003] The present invention generally relates to a turbocharger thermal shield that is further configured to prevent oil leakage in response to turbocharger degradation. Background Technology

[0004] Modern internal combustion engines (both gasoline and diesel) use turbochargers to improve performance. A turbocharger consists of a compressor, which is powered by a turbine driven by exhaust gas from the engine. A shaft connects the turbine to the compressor, and engine oil is used to lubricate the bearings that hold the shaft in place.

[0005] The turbine rotor can have a radial shape, where exhaust gas enters the flow channel defined by the turbine rotor at a 90-degree angle (e.g., perpendicular to the axis of the shaft). To improve performance, the turbine inlet can be reconfigured to receive flow with components perpendicular to the axis of the shaft and components parallel to the axis of the shaft. These turbines are called mixed-flow radial / axial turbines. For mixed-flow turbines, the diameters of the turbine rotor at both the inlet and outlet are often smaller than in radial inlet designs where the inlet portion of the turbine can be significantly larger than the outlet portion. Therefore, mixed-flow turbines can be manufactured with smaller outer diameters.

[0006] The radial shape results in the rare occurrence of turbocharger shaft degradation, allowing the turbine rotor to pass through the outlet orifice for exhaust gas to flow out of the turbine housing. If such degradation occurs, the turbine rotor is no longer able to prevent the turbocharger's oil seals from breaking and may leak into the turbine housing. If the oil seals break, this allows oil to leak from the turbocharger bearings out of the turbocharger and into the hot exhaust system. Summary of the Invention

[0007] In one example, the problem described above can be solved by a turbocharger comprising: a turbine rotor mounted on a shaft and supported within a turbocharger housing; an oil seal disposed on the shaft to seal the shaft within a bearing housing; and a heat shield located between the oil seal and the turbine rotor within the turbocharger housing, the heat shield having a bore through which the shaft extends, wherein the shaft includes a groove into which the heat shield extends, and wherein the shaft has a shoulder between the oil seal and the heat shield, the shoulder forming an axial end wall of the groove, the heat shield being sized to engage the shoulder and restrict movement of the shaft and the oil seal. In this manner, the heat shield can prevent the oil seal from relocating from a position that allows sealing of oil in the bearing housing in the event of shaft degradation.

[0008] At least a portion of the heat shield may have a radius smaller than the outer radius of the oil seal. For example, the diameter of the hole may be smaller than the outer diameter of the oil seal. The diameter of the hole may be smaller than the diameter of the shaft at the oil seal.

[0009] The shaft may include a groove, and the heat shield extends into the groove. The groove may include a recessed portion of the shaft having a diameter smaller than, for example, the diameter of an adjacent portion of the shaft where the oil seal is located. The groove may be provided between the oil seal and the turbine rotor. At least a portion of the heat shield may be axially aligned with the groove.

[0010] The axial distance between the heat shield and the axial end wall of the groove closest to the oil seal can be less than the distance between the axial end wall of the groove and the axial surface of the oil seal furthest from the heat shield.

[0011] The axial distance between the heat shield and the axial end wall of the groove closest to the oil seal can be less than the distance between the axial end face of the turbocharger housing and the oil seal.

[0012] The gap between the heat shield and the adjacent end face of the turbocharger housing can be less than the axial thickness of the oil seal.

[0013] The shaft can be supported by at least one bearing arranged on the side of the oil seal opposite to the turbine rotor.

[0014] The oil seal can be arranged between the shaft and the housing, at a position along the shaft between the bearing and the heat shield.

[0015] The turbine may be, for example, a mixed-flow turbine configured such that the inflow to the turbine rotor has components in directions perpendicular to and parallel to the axis of rotation of the turbine rotor.

[0016] According to another aspect of this disclosure, a method for assembling the turbocharger described above is provided, the method comprising: loosely assembling the heat shield to the shaft; coupling the turbine rotor to the shaft; mounting the shaft into the turbocharger housing; and coupling the heat shield to the turbocharger housing or another housing of the turbocharger.

[0017] The step of assembling the heat shield to the shaft can be performed before the turbine rotor is coupled to the shaft.

[0018] To avoid unnecessary repetition and textual overlap in this specification, certain features are described only with respect to one or a few aspects or embodiments of this disclosure. However, it should be understood that features described with respect to any aspect or embodiment of this disclosure may also be used with any other aspect or embodiment of this disclosure, which is technically possible.

[0019] It should be understood that the above overview is provided to introduce some concepts in a simplified form, which are further described in the detailed embodiments. This is not intended to identify the key or essential features of the claimed subject matter, and the scope of the claimed subject matter is uniquely defined by the claims appended to the detailed embodiments. Furthermore, the claimed subject matter is not limited to embodiments that address any shortcomings mentioned above or in any part of this disclosure. Attached Figure Description

[0020] Figure 1 The illustration shows a schematic side sectional view of a previous example of a turbocharger.

[0021] Figure 2 A schematic side sectional view of a turbocharger arranged according to the present disclosure is shown.

[0022] Figure 3 The illustration shows a schematic side sectional view of the turbocharger after degradation of the turbocharger arrangement according to the present disclosure.

[0023] Figure 2-3 The figures are shown approximate to scale, but other relative dimensions may be used if needed.

[0024] Figure 4 The illustration shows a flowchart of a method for assembling a turbocharger according to the present disclosure.

[0025] Figure 5 The diagram shows what can be included. Figure 2 and Figure 3 A schematic diagram of an engine with a turbocharger, which could be included in a hybrid vehicle. Detailed Implementation

[0026] The following description relates to systems and methods for turbochargers. Figure 1 The previous example of a turbocharger is shown, where the heat shield includes a bore for allowing the shaft to pass through. The turbocharger further includes an oil seal with bores for allowing the shaft to pass through. Both bores may contain the same diameter. Therefore, if the shaft degrades, the heat shield cannot hold the oil seal in place. Furthermore, the turbocharger would require additional components to hold the oil seal in place, increasing package weight and constraints. Figure 2 and Figure 3 An example of a turbocharger incorporating a heat shield with an orifice smaller than that of the oil seal is shown. The orifice of the heat shield can be reduced while avoiding contact with the shaft via a groove arranged in the shaft, wherein the groove is axially aligned with the heat shield. The heat shield can extend into the groove to a position that would otherwise contact the full diameter of the shaft. The full diameter of the shaft can be larger than the diameter of each of the groove and the orifice of the heat shield. The diameter of the orifice of the heat shield can be larger than the diameter of the groove. Therefore, the heat shield can trap the oil seal and prevent it from moving too far from its initial position, so that if the shaft deteriorates, the oil is retained in the bearing housing. Figure 4 The illustration shows a method for assembling a turbocharger that includes a heat shield and grooves. Figure 5 The illustration shows an embodiment of a vehicle with an engine equipped with a turbocharger, which may be similar to... Figure 2 and Figure 3 The turbocharger.

[0027] Figure 1-3 and Figure 5Example configurations with various relative positions of components are shown. In at least one example, if such components are shown to be in direct contact or directly connected to each other, then such components can be referred to as being in direct contact or directly connected, respectively. Similarly, in at least one example, components shown to be adjacent to each other or next to each other can be referred to as being adjacent to each other or next to each other, respectively. As an example, the placement of components in coplanar contact can be referred to as coplanar contact. As another example, in at least one example, components set apart from each other with only space between them and no other components can be referred to as such. As yet another example, components shown to be above / below each other, on opposite sides of each other, or to the left / right of each other can be referred to as such relative to each other. Additionally, as shown in the figures, in at least one example, the topmost component or the apex of a component can be referred to as the “top” of the component, and the bottommost component or the lowest point of a component can be referred to as the “bottom” of the component. As used herein, top / bottom, upper / lower, above / below can be relative to the vertical axis of the figure and are used to describe the positioning of the components of the figure relative to each other. Thus, in one example, a component shown above other components is positioned vertically above the other components. As yet another example, the shape of an element depicted in a figure may be described as having those shapes (e.g., such as circular, straight, flat, curved, rounded, chamfered, angled, etc.). Additionally, in at least one example, elements shown intersecting each other may be described as intersecting elements or intersecting with each other. Furthermore, in one example, an element shown inside or outside another element may be described as such. It should be recognized that one or more parts described as “substantially similar and / or identical” differ from each other in terms of manufacturing tolerances (e.g., within 1-5% deviation).

[0028] Note that Figure X shows arrows indicating where gas flow exists, and the solid lines of the device walls show where flow is blocked, and communication is impossible due to the lack of fluid connectivity created by the device walls spanning from one point to another. The walls create separation between regions, except for openings within the walls that allow for the described fluid connectivity.

[0029] Reference Figure 1 The previous example of the proposed turbocharger 2 includes a turbine 3, which includes a turbine rotor 4 disposed within a turbine housing 8. As depicted, the turbine 3 is a mixed-flow turbine configured such that the inlet flow of exhaust gas to the turbine rotor 4 has components in directions parallel and perpendicular to the axis of rotation of the turbine rotor 4.

[0030] The turbine rotor 4 is mounted on the shaft 6 of the turbocharger 2. The shaft 6 is supported by bearings (not shown) and housed in the bearing housing 14 of the turbocharger 2 to allow the turbine rotor 4 to rotate within the turbine housing 8.

[0031] An oil seal 12 is disposed within the bearing housing 14, between the inner wall 14a of the bearing housing 14 and the shaft 6. The oil seal 12 is configured to prevent oil from leaking from the bearing housing 14 into the turbine housing 8 or into the exhaust system.

[0032] The oil seal 12 can extend circumferentially around the shaft 6, such that the inner circumferential surface of the oil seal 12, with a diameter d3, forms a surface parallel to the outer circumference of the shaft 6. As depicted, a radial clearance 7 can exist between the inner circumferential surface of the oil seal 12 and the shaft 6. However, in other arrangements, the radial clearance may be absent; for example, the oil seal 12 can occupy the entire radial space between the shaft and the bearing housing. Alternatively, another seal can be provided in the radial clearance 7 between the oil seal 12 and the shaft 6.

[0033] The oil seal 12 may include a seal of a desired form capable of preventing oil leakage from the bearing housing. For example, the seal may include a lip seal, a brush seal, or a face seal.

[0034] The turbocharger 2 further includes a heat shield 10, which is arranged to reduce heating of the bearing housing 14 and the bearing by hot exhaust gas.

[0035] The heat shield 10 may be rigid or flexible, and may be made of materials such as steel, aluminum or composite materials or fabric materials, and may include a heat barrier coating (such as a ceramic heat barrier coating) provided on one or more surfaces of the heat shield.

[0036] As depicted, a heat shield 10 can be arranged between the turbine rotor 4 and the turbine housing 8 and the bearing housing 14. The heat shield thus forms a barrier between the hot exhaust gas passing through the turbine 3 and the bearing housing 14.

[0037] The heat shield 10 extends generally around the circumference of the axis 6 and includes a hole 10a through which the axis extends.

[0038] During the assembly of the turbocharger 2, the heat shield 10 can be fixed to the bearing housing 14, and the shaft 6 is then inserted through the hole in the heat shield 10.

[0039] In some arrangements, the oil seal 12 is mounted on the shaft 6 before the shaft is inserted through the hole in the heat shield 10. Alternatively, the oil seal 12 may be inserted through the hole 10a in the heat shield and coupled to the bearing housing 14 before the shaft 6 is assembled into the turbocharger 2.

[0040] In any case, it is desirable that the diameter d1 of the hole 10a is equal to or greater than the outer diameter d2 of the oil seal 12, so that the oil seal 12 and the shaft 6 can be assembled through the hole 10a.

[0041] When the turbocharger 2 is assembled, an axial clearance can be provided between the turbine 4 and the heat shield 10, and a radial clearance can be provided between the shaft 6 and the heat shield 10, thereby allowing the shaft 6 to rotate without wear between components.

[0042] Turn now Figure 2 The turbocharger 102 arranged according to this disclosure includes a turbine 103 having a turbine rotor 104 supported within a turbine housing 108. The turbine rotor 104 is mounted on a shaft 106 of the turbocharger. The turbine rotor 104, turbine housing 108, and shaft 106 can be similar to those described above. Figure 1 The turbine rotor 4, turbine housing 8, and shaft 6 are described.

[0043] A heat shield 110 is located between the turbine 103 of the turbocharger 102 and the bearing housing 114. The turbocharger 102 further includes an oil seal 112 disposed within the bearing housing 114. The features described above regarding the oil seal 12 and the heat shield 10 are equally applicable to the oil seal 112 and the heat shield 110, respectively.

[0044] The difference between heat shield 110 and heat shield 10 is that heat shield 110 is further configured to substantially maintain the position of oil seal 112 in the event of turbocharger 102 degradation.

[0045] At least a portion of the heat shield extends inward, such that the inner radius of at least a portion of the heat shield is smaller than the outer radius of the oil seal 112. Figure 2 In the arrangement described in the example, the hole 110a of the heat shield 110 has a diameter d100 smaller than the outer diameter d200 of the oil seal 112. However, in other arrangements, the hole may have a diameter larger than the outer diameter of the oil seal 112, and the portion 110b may include one or more protrusions extending radially inward from the edge of the hole.

[0046] If it has a mixed-flow turbine and conventional heat shield (such as...) Figure 1 The turbocharger with heat shield 10) Figure 3 If the turbine rotor 104 degrades (e.g., breaks) at point 120 on shaft 106 as shown in the diagram, it may be able to escape from turbine housing 108 through the exhaust outlet. Since the oil seal 112 is attached to the portion of turbocharger shaft 106 that is still fixed to turbine 103, it will move with it. Therefore, if the turbine is able to detach from turbine housing 108, the oil seal will travel with it, allowing oil to escape into the hot exhaust system, resulting in further degradation.

[0047] In contrast, Figure 3 In this arrangement, where the heat shield portion 110b has a heat shield 110 with a diameter smaller than the outer diameter of the oil seal 112, the heat shield 110 serves to retain the oil seal 112 within the bearing housing 114, thereby preventing oil leakage from the bearing housing 114 into the turbocharger housing 108. This can occur when the shaft 106 breaks on the side of the bearing housing opposite to the turbine housing (e.g., at point 120). In other words, when shaft degradation occurs at a location between the degradation and the heat shield, the heat shield prevents oil leakage from the bearing housing.

[0048] The heat shield 110 according to this disclosure therefore provides the additional function of preventing oil leakage in the event of turbocharger 102 failure. This prevents turbocharger oil from reaching the hot exhaust system. As mentioned above, at least because the diameter of the heat shield is equal to the diameter of the oil seal, conventional heat shields (such as...) Figure 1 The turbocharger with heat shield 10) does not provide the oil seal retention function. In addition, as mentioned above, heat shield 110 may have a diameter equal to that of oil seal 112; however, protrusions or other surface features may be included in turbocharger 102 such that the effective diameter of heat shield is smaller than that of oil seal 112.

[0049] In some arrangements, the oil seal 112 can be axially held in place by a first axial retainer 116 located between the compressor rotor (not shown) and the oil seal 112 (e.g., on the side of the oil seal opposite to the turbine rotor 4).

[0050] Alternatively or additionally, the oil seal 112 may be axially held in place by a second axial retainer 118 located between the turbine 104 and the oil seal 112 and axially adjacent to the oil seal 112.

[0051] Axial retainers 116, 118 may form part of shaft 106. Alternatively, one or both of axial retainers 116, 118 may be separate components. For example, the first or second axial retainer may be formed by a shoulder provided on shaft 106.

[0052] Return to Figure 2In one arrangement, the shaft 106 may include a recessed portion or groove 107 at a location between the turbine rotor 104 and the oil seal 112. The diameter at the base of the groove 107 may be smaller than the diameter of the second axial retainer 118. The diameter at the base of the groove may be smaller than the diameter of the shaft adjacent to the groove. For example, the diameter at the base of the groove may be smaller than the diameter of the portion of the shaft 106 axially aligned with the oil seal 112 and / or the diameter of the portion of the shaft 106 axially aligned with a bearing (not shown). Therefore, the diameter at the recessed portion 107 of the shaft may be smaller than the inner diameter d100 of the oil seal 112.

[0053] As in Figure 2 As shown, the second axial retainer 118 can form the axial end wall 107a of the groove 107 closest to the oil seal 112. Additionally or alternatively, the turbine rotor 104 can form the opposing axial end wall 107b of the groove 107. In an alternative arrangement, a shoulder formed on the shaft 106 can provide one or more of the axial end walls 107a, 107b of the groove 107. That is, the shaft 106 returns to its original diameter outside the groove 107, such that the portion of the shaft immediately outside the groove forms the end wall of the groove.

[0054] As in Figure 2 As depicted, at least a portion 110 of the heat shield can be axially aligned within the groove 107. The heat shield 110 extends radially inward into the groove. The inner radius of at least this portion 110b of the heat shield is therefore smaller than the inner radius of the oil seal 112 and / or the outer diameter of the shaft 106 at the location of the oil seal 112. Figure 2 In the arrangement shown, the diameter d100 of the heat-shielded hole 110a is smaller than the inner diameter d300 of the oil seal 112.

[0055] The turbocharger 102 is configured such that, in the event of turbocharger shaft 106 degradation, the shaft or a component attached to the shaft (such as the second axial retainer 118) contacts the heat shield 110 before the shaft can continue to move and cause the oil seal 112 to be damaged.

[0056] exist Figure 2In the arrangement depicted, the axial distance between the heat shield 110 and the axial end wall 107a of the recess 107 closest to the oil seal 112 is less than the distance between the axial end face of the turbocharger housing 114b and the oil seal 112. Therefore, in the unlikely event of turbocharger 102 degradation, the heat shield 110 will prevent the second axial retainer 118 from axially moving toward the turbine 103, keeping the oil seal 112 in contact with the inner wall 114a of the bearing housing 114 along its entire axial length. This prevents the formation of an open channel between the bearing housing 114 and the thermal exhaust system through which oil could otherwise flow.

[0057] In other arrangements, the axial distance between the heat shield 110 and the axial end wall 107a of the groove 107 closest to the oil seal 112 can be less than the distance between the axial end wall of the groove 107a and the axial surface of the oil seal 112 furthest from the heat shield 110. In such arrangements, at least a portion of the oil seal 112 remains within the bearing housing 114, for example, in contact with the inner wall 114a, to limit oil leakage.

[0058] In some arrangements, the axial thickness of the oil seal 112 may be greater than the axial clearance between the heat shield 110 and the bearing housing 114, so that the oil seal 112 cannot pass between the heat shield 110 and the bearing housing 114.

[0059] As mentioned above Figure 1 The previously described turbocharger example can be assembled in such a manner that the heat shield 10 is secured to the bearing housing beforehand, and the oil seal 12 and turbine rotor 4 are subsequently assembled onto the shaft 6, before the free end of the shaft 6 is inserted into the bearing housing 14 through the hole 10a in the heat shield 10. However, for the turbocharger according to... Figure 2 For example, in the turbocharger 102, this assembly sequence is not feasible because the heat shield hole 110a has a smaller diameter than the outer diameter d200 of the oil seal 112 and the shaft 106 at the location of the oil seal 112.

[0060] Reference Figure 4 The turbocharger 2 can be assembled using method 400 according to an embodiment of the present disclosure. In a first step 402 of the method, the heat shield 110 is loosely assembled to the shaft 106. In a second step 404, the turbine rotor 104 is coupled to the shaft 106, for example by welding, brazing, or any other desired fixing method. In a third step 406, the shaft 106 is assembled into the bearing housing 114.

[0061] In the fourth step 408, the heat shield 110 is attached to components of the turbocharger 102, such as the bearing housing 114 and / or the turbine housing 108. The heat shield 110 may be attached to the housing of the turbocharger 102 by means including, but not limited to, clamping with stainless steel clips or bonding with high-temperature tape or adhesive.

[0062] Figure 5 An engine system 1000 for a vehicle is depicted. The vehicle may be a road vehicle with drive wheels in contact with the road surface. The engine system 1000 includes an engine 1010, which contains a plurality of cylinders. Figure 5 A cylinder or combustion chamber is described in detail. Various components of the engine 1010 can be controlled by the electronic engine controller 1012.

[0063] Engine 1010 includes a cylinder block 1014 and a cylinder head 1016, the cylinder block 1014 including at least one cylinder bore, and the cylinder head 1016 including an intake valve 1152 and an exhaust valve 1154. In other examples, where engine 1010 is configured as a two-stroke engine, cylinder head 1016 may include one or more intake ports and / or exhaust ports. Cylinder block 1014 includes cylinder walls 1032, in which a piston 1036 is disposed and connected to a crankshaft 1040. Thus, when coupled together, cylinder head 1016 and cylinder block 1014 may form one or more combustion chambers. Therefore, the volume of combustion chamber 1030 is adjusted based on the oscillation of piston 1036. Combustion chamber 1030 may also be referred to herein as cylinder 1030. Combustion chamber 1030 is shown communicating with intake manifold 1144 and exhaust manifold 1148 via corresponding intake valve 1152 and exhaust valve 1154. Each intake and exhaust valve can be operated by intake cam 1051 and exhaust cam 1053. Alternatively, one or more of the intake and exhaust valves can be operated by electromechanically controlled valve coils and armature assemblies. The position of intake cam 1051 can be determined by intake cam sensor 1055. The position of exhaust cam 1053 can be determined by exhaust cam sensor 1057. Thus, when valves 1152 and 1154 are closed, combustion chamber 1030 and cylinder bores can be fluidly sealed, preventing gases from entering or leaving combustion chamber 1030.

[0064] Combustion chamber 1030 may be formed by cylinder walls 1032, piston 1036, and cylinder head 1016 of cylinder block 1014. Cylinder block 1014 may include cylinder walls 1032, piston 1036, crankshaft 1040, etc. Cylinder head 1016 may include one or more fuel injectors (such as fuel injector 1066), one or more intake valves 1152, and one or more exhaust valves (such as exhaust valve 1154). Cylinder head 1016 may be connected to cylinder block 1014 via fasteners (such as bolts and / or screws). Specifically, when coupled, the cylinder block 1014 and cylinder head 1016 can be in sealing contact with each other via gaskets, and thus the cylinder block 1014 and cylinder head 1016 can seal the combustion chamber 1030 such that when the intake valve 1152 is opened, gas can only flow into the combustion chamber 1030 via the intake manifold 1144, and / or when the exhaust valve 1154 is opened, gas can only flow out of the combustion chamber 1030 via the exhaust manifold 1148. In some examples, only one intake valve and one exhaust valve may be included for each combustion chamber 1030. However, in other examples, each combustion chamber 1030 of the engine 1010 may include more than one intake valve and / or more than one exhaust valve.

[0065] In some examples, each cylinder of engine 1010 may include a spark plug 1192 for initiating combustion. In a selected operating mode, in response to a spark advance signal SA from controller 1012, ignition system 1190 is able to provide an ignition spark to cylinder 1014 via spark plug 1192. However, in some embodiments, spark plug 1192 may be omitted, such as in cases where engine 1010 can initiate combustion via automatic ignition or fuel injection, as is the case with some diesel engines.

[0066] Fuel injector 1066 can be configured to inject fuel directly into combustion chamber 1030, a technique known to those skilled in the art as direct injection. Fuel injector 1066 delivers liquid fuel in proportion to the pulse width of the signal FPW from controller 1012. Fuel is delivered to fuel injector 1066 via a fuel system (not shown) including a fuel tank, fuel pump, and fuel rail (not shown). A driver 1068, in response to controller 1012, supplies operating current to fuel injector 1066. In some examples, engine 1010 may be a gasoline engine, and the fuel tank may include gasoline, which can be injected into combustion chamber 1030 via injector 1066. However, in other examples, engine 1010 may be a diesel engine, and the fuel tank may include diesel fuel, which can be injected into combustion chamber 1030 via injector 1066. Additionally, in such examples where engine 1010 is configured as a diesel engine, engine 1010 may include glow plugs to initiate combustion in combustion chamber 1030.

[0067] Intake manifold 1144 is shown communicating with throttle valve 1062, which adjusts the position of throttle plate 1064 to control airflow to engine cylinder 1030. This may include controlling the airflow of boosted air from intake boost chamber 1146. In some embodiments, throttle valve 1062 may be omitted, and airflow to the engine may be controlled via a single air intake system throttle valve (AIS throttle valve) 1082, which is coupled to air intake passage 42 and disposed upstream of intake boost chamber 1146. In a further example, AIS throttle valve 1082 may be omitted, and airflow to the engine may be controlled using throttle valve 1062.

[0068] In some embodiments, engine 1010 is configured to provide exhaust gas recirculation (EGR) or EGR. When EGR is included, it can be provided as high-pressure EGR and / or low-pressure EGR. In an example where engine 1010 includes low-pressure EGR, low-pressure EGR can be provided to the engine intake system from a location in the exhaust system downstream of turbine 1164 at a location downstream of air intake system (AIS) throttle 1082 and upstream of compressor 1162 via EGR passage 1135 and EGR valve 1138. EGR can be drawn from the exhaust system into the air intake system when a pressure differential of the drive airflow is present. The pressure differential can be generated by partially closing AIS throttle 1082. Throttle 1084 controls the pressure at the inlet of compressor 1162. AIS can be electrically controlled and its position can be adjusted based on optional position sensor 1088.

[0069] Ambient air is drawn into the combustion chamber 1030 via an intake passage 1042 including an air filter 1156. Therefore, air first enters the intake passage 1042 through the air filter 1156. The compressor 1162 then draws in air from the intake passage 1042, so that it passes through the compressor outlet pipe ( Figure 5 Compressed air is supplied to the booster chamber 1146 (not shown). In some examples, the air intake passage 1042 may include an air chamber (not shown) with a filter. In one example, the compressor 1162 may be a turbocharger, wherein power is drawn to the compressor 1162 from the exhaust flow through the turbine 1164. Specifically, the exhaust can rotate the turbine 1164, which is coupled to the compressor 1162 via a shaft 1161. The shaft 1161 may be similar to... Figure 2 The shaft 106. The wastegate 1072 allows exhaust gas to bypass the turbine 1164, enabling control of the boost pressure under varying operating conditions. In response to increased boost demand (such as during operator accelerator pedal operation), the wastegate 1072 can be closed (or the wastegate opening can be reduced). Closing the wastegate increases the exhaust pressure upstream of the turbine, thereby increasing turbine speed and peak power output. This allows for increased boost pressure. Furthermore, when the compressor recirculation valve is partially open, the wastegate can be moved toward the closed position to maintain the desired boost pressure. In another example, in response to decreased boost demand (such as during operator accelerator pedal release), the wastegate 1072 can be opened (or the wastegate opening can be increased). Opening the wastegate reduces the exhaust pressure, thereby reducing turbine speed and turbine power. This allows for reduced boost pressure.

[0070] However, in an alternative embodiment, compressor 1162 may be a mechanical supercharger, wherein power is drawn from crankshaft 1040 to compressor 1162. Therefore, compressor 1162 may be coupled to crankshaft 1040 via a mechanical linkage such as a belt. Thus, a portion of the rotational energy output from crankshaft 1040 may be transferred to compressor 1162 to power compressor 1162.

[0071] A compressor recirculation valve (CRV) 1158 can be provided in a compressor recirculation path 1159 surrounding compressor 1162, such that air can move from compressor outlet to compressor inlet to reduce the pressure that can form across compressor 1162. A boost air cooler 1157 can be located in a boost chamber 1146 downstream of compressor 1162 for cooling the boost air supplied to the engine intake system. However, in situations such as... Figure 1In some other examples shown, the boost air cooler 1157 may be located in the intake manifold 1144 downstream of the electronic throttle valve 1062. In some examples, the boost air cooler 1157 may be an air-to-air boost air cooler. However, in other examples, the boost air cooler 1157 may be a liquid-to-air cooler.

[0072] In the depicted example, compressor recirculation path 1159 is configured to recirculate cooled compressed air from upstream of booster air cooler 1157 to the compressor inlet. In an alternative example, compressor recirculation path 1159 may be configured to recirculate compressed air from downstream of the compressor and downstream of booster air cooler 1157 to the compressor inlet. CRV 1158 can be opened and closed by an electrical signal from controller 1012. CRV 1158 may be configured as a three-state valve with a default half-open position, capable of moving from the half-open position to the fully open or fully closed position.

[0073] A universal exhaust oxygen (UEGO) sensor 1126 is shown coupled to the exhaust manifold 1148 upstream of the emission control unit 1070. Alternatively, a dual-state exhaust oxygen sensor may replace the UEGO sensor 1126. In one example, the emission control unit 1070 may include multiple catalyst blocks. In another example, multiple emission control units, each having multiple blocks, can be used. Although the described example shows the UEGO sensor 1126 upstream of the turbine 1164, it should be recognized that in alternative embodiments, the UEGO sensor may be located downstream of the turbine 1164 and upstream of the emission control unit 1070 in the exhaust manifold. Additionally or alternatively, the emission control unit 1070 may include a diesel oxidation catalyst (DOC) and / or a diesel cold start catalyst, a particulate filter, a three-way catalytic converter, a NOx trap, a selective catalytic reduction device, and combinations thereof. In some examples, a sensor may be arranged upstream or downstream of the emission control unit 1070, wherein the sensor may be configured to diagnose the condition of the emission control unit 1070.

[0074] Controller 1012 in Figure 1The computer, shown as a microcomputer, includes: a microprocessor unit (CPU) 1102, an input / output port (I / O) 1104, a read-only memory (ROM) 1106, a random access memory (RAM) 1108, a keep-alive memory (KAM) 1110, and a conventional data bus. The controller 1012 is shown to receive various signals from sensors coupled to the engine 1010, including, in addition to those previously discussed, the following: engine coolant temperature (ECT) from temperature sensor 1172 coupled to cooling sleeve 1174; position sensor 1134 coupled to input device 1131 for sensing input device pedal position (PP) adjusted by vehicle operator 1132; knock sensor (not shown) for determining exhaust ignition; engine manifold pressure (MAP) measurement from pressure sensor 1121 coupled to intake manifold 1144; boost pressure measurement from pressure sensor 1122 coupled to boost chamber 1146; engine position sensor from Hall effect sensor 1118 sensing crankshaft 1040 position; mass of air entering the engine from sensor 1120 (e.g., hot-wire airflow meter); and throttle position measurement from sensor 1058. Atmospheric pressure may also be sensed (sensor not shown) for processing by the controller 1012. In a preferred aspect of the invention, the Hall effect sensor 1118 generates a predetermined number of equally spaced pulses with each rotation of the camshaft, thereby enabling the determination of the engine speed (RPM). The input device 1130 may include an accelerator pedal and / or a brake pedal. Therefore, the output from the position sensor 1134 can be used to determine the position of the accelerator pedal and / or brake pedal of the input device 1130, and thus determine the desired engine torque. Therefore, the desired engine torque, as requested by the vehicle operator 1132, can be estimated based on the pedal position of the input device 1130.

[0075] In some examples, vehicle 1005 may be a hybrid vehicle having multiple torque sources available for one or more wheels 1059. In other examples, vehicle 1005 may be a conventional vehicle with only an engine, or an electric vehicle with only one or more electric motors. In the example shown, vehicle 1005 includes an engine 1010 and an electric motor 1052. Electric motor 1052 may be a motor or a motor / generator (M / G). When one or more clutches 1056 are engaged, the crankshaft 1040 of engine 1010 and electric motor 1052 are connected to wheels 1059 via transmission 1054. In the depicted example, a first clutch 1056 is provided between crankshaft 1040 and electric motor 1052, and a second clutch 1056 is provided between electric motor 1052 and transmission 1054. The controller 1012 can send signals to the actuators of each clutch 1056 to engage or disengage the clutch, thereby connecting or disconnecting the crankshaft 1040 from the motor 1052 and its connected components, and / or connecting or disconnecting the motor 1052 from the transmission 1054 and its connected components. The transmission 1054 can be a gearbox, a planetary gear system, or other type of transmission. The powertrain can be configured in various ways, including as a parallel, series, or series-parallel hybrid vehicle.

[0076] Motor 1052 receives electrical power from traction battery 1061 to provide torque to wheel 1059. Motor 1052 can also operate as a generator, for example, during braking operation, to provide electrical power to recharge battery 1061.

[0077] Controller 1012 from Figure 5 Various sensors receive signals and employ Figure 5 Various actuators are used to adjust engine operation based on received signals and instructions stored in the controller's memory. For example, adjusting the operation of motor 1052 can occur based on feedback from ECT sensor 1112. As will be described in more detail below, engine 1010 and motor 1052 can be adjusted such that their operation can be delayed based on one or more of the powertrain temperature (which can be estimated based on feedback from ECT sensor 1112) and the distance between the expected destination and the range of electric operation only.

[0078] Therefore, in one embodiment, the turbocharger can be improved by extending a heat shield disposed between the turbine impeller and the oil seal assembly into a recess disposed in the shaft. The recess can also be disposed between the turbine impeller and the oil seal assembly. By arranging the recess, the heat shield can be extended without introducing increased wear on the shaft, while also shaping the heat shield to prevent the oil seal assembly from releasing the oil seal in the event of shaft degradation (e.g., cracking). The heat shield still allows the turbine impeller to remain in the turbine housing while holding the oil seal assembly in a position that still prevents oil from flowing into the exhaust passages. To achieve this configuration, the heat shield can be loosely mounted to the turbine shaft before the turbo motor is mounted to the shaft. The heat shield can then be fixedly coupled to one or more of the turbine housing and / or bearing housing, thereby allowing the heat shield to prevent the bearing housing from direct contact with exhaust heat in the event of turbocharger shaft degradation while preventing excessive movement of the oil seal assembly. Excessive movement of the oil seal assembly can include the oil seal moving a certain amount to allow oil to flow through the oil seal and into the exhaust passages. Therefore, if the shaft degrades, the oil seal may move, but due to the heat shield arrangement described above, it will not move enough to allow oil leakage.

[0079] In this manner, a heat shield can be installed within the turbine housing, extending into a recess arranged within the turbocharger shaft. This recess allows the heat shield to extend further radially inward without increasing wear on the turbocharger shaft. The technical effect of this radially inwardly extending heat shield is to prevent the oil seals from rupturing if the turbocharger shaft degrades. The heat shield also prevents the oil seals from escaping with the turbine impeller.

[0080] Note that the example control and estimation programs included herein can be used with various engine and / or vehicle system configurations. The control methods and programs disclosed herein can be stored as executable instructions in non-transitory memory and can be executed by a control system including controllers integrated with various sensors, actuators, and other engine hardware. The specific programs described herein can represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, etc. Therefore, the various actions, operations, and / or functions described can be executed in the order shown, in parallel, or in some cases omitted. Similarly, the processing order is not necessarily required to realize the features and advantages of the example embodiments of the invention described herein, but is provided for ease of illustration and explanation. Depending on the specific strategy used, one or more of the shown actions, operations, and / or functions can be repeatedly executed. Furthermore, the described actions, operations, and / or functions can be graphically represented as code encoded in a non-transitory memory of a computer-readable storage medium within an engine control system, wherein the described actions are realized by cooperating with an electronic controller to execute instructions in a system including various engine hardware components.

[0081] It should be recognized that the configurations and procedures disclosed herein are exemplary in nature, and these specific embodiments are not intended to be limiting, as many variations are possible. For example, the above-described techniques can be applied to V-6, I-4, I-6, V-12, opposed 4-cylinder, and other engine types. The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and constructions and other features, functions, and / or properties disclosed herein.

[0082] As used herein, the term “approximate” is interpreted as the average of the range ±5%, unless otherwise specified.

[0083] The following claims specifically point to certain combinations and sub-combinations that are considered novel and non-obvious. These claims may relate to a "one" element or a "first" element or its equivalent. These claims should be understood to include combinations of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and / or characteristics may be claimed by amending existing claims or by filing new claims in this or related applications. These claims, whether broader, narrower, identical, or different from the scope of the original claims, are considered to be included within the subject matter of this disclosure.

Claims

1. A turbocharger, comprising: A turbine rotor, which is mounted on a shaft and supported within a turbocharger housing; An oil seal is disposed on the shaft to seal the shaft within a bearing housing; as well as A heat shield is located between the oil seal and the turbine rotor within the turbocharger housing. The heat shield has a hole through which the shaft extends, wherein the shaft includes a groove, the heat shield extends into the groove, and wherein the shaft has a shoulder between the oil seal and the heat shield, the shoulder forming an axial end wall of the groove. The heat shield is sized to engage the shoulder and restrict movement of the shaft and the oil seal, and the heat shield is fixedly coupled to the bearing housing.

2. The turbocharger of claim 1, wherein at least a portion of the heat shield has a radius smaller than the outer radius of the oil seal.

3. The turbocharger according to claim 1, wherein the diameter of the orifice is smaller than the outer diameter of the oil seal.

4. The turbocharger of claim 1, wherein the diameter of the bore is smaller than the diameter of the shoulder of the shaft at the oil seal, and wherein the diameter of the bore is larger than the diameter of the groove.

5. The turbocharger of claim 1, wherein the axial distance between the heat shield and the axial end wall of the groove closest to the oil seal is less than the distance between the axial end wall of the groove and the axial surface of the oil seal furthest from the heat shield.

6. The turbocharger of claim 5, wherein the axial distance between the heat shield and the axial end wall of the groove closest to the oil seal is less than the distance between the axial end face of the turbocharger housing and the oil seal.

7. The turbocharger according to claim 1, wherein the gap between the heat shield and the adjacent end faces of the turbocharger housing is less than the axial thickness of the oil seal.

8. The turbocharger of claim 1, wherein the shaft is supported by a portion of the bearing housing on the side of the oil seal opposite to the turbine rotor.

9. The turbocharger of claim 1, wherein the oil seal is disposed between the shaft and the bearing housing, at a location along the shaft between the bearing and the thermal shield.

10. The turbocharger of claim 1, wherein the turbine of the turbocharger is a mixed-flow turbine.

11. A turbocharger, comprising: A turbine, which is connected to a shaft, and the turbine and the shaft are housed in a turbine housing; An oil seal is disposed between the shaft and the turbine housing; as well as A heat shield is disposed between the turbine and the oil seal, the heat shield extending radially inward into a groove disposed in the shaft, wherein a heat shield hole and an oil seal hole allow the shaft to extend through them, wherein the diameter of the heat shield hole is smaller than the diameter of the oil seal hole, and wherein the heat shield is secured to the turbine housing. The oil seal is arranged on the shaft to seal the shaft within the bearing housing; and The shaft has a shoulder between the oil seal and the heat shield, the shoulder forming an axial end wall of the groove, and the heat shield is sized to engage the shoulder and restrict movement of the shaft and the oil seal.

12. The turbocharger of claim 11, wherein the oil seal is shaped to prevent oil from flowing from the bearing housing to the exhaust passage, and wherein the heat shield maintains the position of the oil seal during the degradation of the shaft.

13. The turbocharger of claim 12, wherein the degradation of the shaft includes cracking or breakage.

14. The turbocharger of claim 12, wherein the turbine rotor disengages from the turbine housing in response to the degradation of the shaft.

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