Supercharging device

Abstract

To provide a supercharging device capable of suppressing increase in the sizes of a thrust bearing and a supercharger while enabling both of improvement of efficiency of the supercharger and reliability of the thrust bearing.SOLUTION: A supercharging device includes a supercharger. The supercharger includes: a compressor impeller including a compressor disk; a turbine disk; a rotating shaft coupling the compressor impeller and the turbine disk to each other; and a thrust bearing regulating axial movement of the rotating shaft. The supercharging device includes: a compressed air supply line configured to supply compressed air to a back surface of the compressor disk or a back surface of the turbine disk; a valve provided in the compressed air supply line; and a control device configured to control an opening of the valve on the basis of thrust load from the rotating shaft to the thrust bearing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a supercharging device. [Background technology]

[0002] In a turbocharger, if the thrust load on the thrust bearing increases due to the pressure of exhaust gas supplied from the engine, this will lead to a decrease in the efficiency of the turbocharger due to increased mechanical loss in the thrust bearing, and a decrease in the reliability of the thrust bearing (increased risk of damage to the thrust bearing).

[0003] Patent Document 1 describes that the thrust load is reduced by supplying compressed air from a compressor of a supercharger to the back side of a turbine.

[0004] Patent Document 2 describes that in a turbocharger, a thrust load is calculated based on the inlet pressure and outlet pressure of a turbine and the inlet pressure and outlet pressure of a compressor, and the thrust load is reduced by controlling the value of a current applied to an electromagnet in accordance with the thrust load. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-117753 [Patent Document 2] JP 2018-159300 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the configuration described in Patent Document 1, the amount of compressed air supplied to the back of the turbine is determined by the specifications at the time of designing the turbocharger, and it is not possible to appropriately reduce the thrust load when the thrust load increases or decreases due to engine load fluctuations. Therefore, there is room for improvement in terms of turbocharger efficiency and thrust bearing reliability.

[0007] In the configuration described in Patent Document 2, the thrust load can be reduced by controlling the value of the current applied to the electromagnet even when the engine load fluctuates. However, the electromagnet and the installation space therefor must be provided inside the turbocharger, which tends to increase the size of the turbocharger and the associated weight.

[0008] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a turbocharging device that can improve the efficiency of the turbocharger and the reliability of the thrust bearing while suppressing increases in the size of the thrust bearing and the turbocharger. [Means for solving the problem]

[0009] In order to achieve the above object, a supercharging device according to at least one embodiment of the present disclosure includes: A supercharging device including a supercharger, The turbocharger is a compressor impeller including a compressor disc; A turbine disc, a rotating shaft connecting the compressor impeller and the turbine disk; a thrust bearing that restricts axial movement of the rotating shaft; Including, The supercharging device is a compressed air supply line configured to supply compressed air to the rear surface of the compressor disk or the rear surface of the turbine disk; a valve provided in the compressed air supply line; a control device configured to control an opening degree of the valve based on a thrust load from the rotating shaft to the thrust bearing; Equipped with. [Effects of the Invention]

[0010] According to at least one embodiment of the present disclosure, a turbocharger is provided that can improve the efficiency of the turbocharger and the reliability of the thrust bearing while suppressing increases in the size of the thrust bearing and the turbocharger. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic configuration diagram of a supercharger 2 according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a hardware configuration of a control device 34. [Figure 3] FIG. 3 is a block diagram showing an example of the functional configuration of a control device 34. [Figure 4] 4 is a flow chart showing an example of control of the opening degree of the motor-operated valve 32 using the control device 34 shown in FIG. [Figure 5] FIG. 10 is a diagram showing an example of thrust load correlation information R1. [Figure 6] FIG. 10 is a diagram showing another example of the thrust load correlation information R1. [Figure 7] FIG. 10 is a diagram for explaining a method for setting a threshold value Lth. [Figure 8] FIG. 10 is a diagram showing an example of back pressure correlation information R2. [Figure 9] FIG. 4 is a schematic configuration diagram of a supercharger 2 according to another embodiment. [Figure 10] FIG. 10 is a schematic diagram of a supercharger 02 according to a comparative example. [Figure 11] 11 is a diagram showing a comparison of thrust load and the like according to operating conditions of the supercharger between the embodiment shown in FIG. 9 and the comparative embodiment shown in FIG. [Figure 12] 12 is a diagram for explaining the two operating conditions shown in FIG. 11. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the invention. For example, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement exactly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. On the other hand, the expressions "comprise," "include," "have," "includes," or "have" of one element are not exclusive expressions that exclude the presence of other elements.

[0013] FIG. 1 is a schematic diagram of a supercharger 2 according to one embodiment. As shown in Fig. 1, the turbocharger 2 includes a turbocharger 3. The turbocharger 3 includes a compressor 4, a turbine 5, a rotating shaft 6 connecting the compressor 4 and the turbine 5, and a bearing device 7 supporting the rotating shaft 6. In the example shown in the figure, the compressor 4 is a centrifugal compressor, and the turbine 5 is an axial turbine. Hereinafter, the radial direction of the rotating shaft 6 will be simply referred to as the "radial direction," the axial direction of the rotating shaft 6 will be simply referred to as the "axial direction," and the circumferential direction of the rotating shaft 6 will be simply referred to as the "circumferential direction."

[0014] The compressor 4 includes a compressor impeller 8, which includes a compressor disk 10 having a generally truncated cone shape and a plurality of compressor blades 12 provided at intervals in the circumferential direction on the outer peripheral surface of the compressor disk 10.

[0015] The turbine 5 includes a substantially circular turbine disk 18 and a plurality of turbine blades 20 provided at intervals in the circumferential direction on the outer peripheral surface of the turbine disk 18. The compressor impeller 8 and the turbine disk 18 are connected by a rotary shaft 6 and arranged coaxially.

[0016] The bearing device 7 includes a pair of journal bearings 22 that rotatably support the rotating shaft 6, and a thrust bearing 24 that restricts axial movement of the rotating shaft 6. The pair of journal bearings 22 and the thrust bearing 24 are supported by a casing (stationary wall) (not shown) of the turbocharger 3.

[0017] The pair of journal bearings 22 are arranged with a gap between them in the axial direction. In the illustrated exemplary embodiment, the thrust bearing 24 is configured to receive an axial thrust load L from the rotating shaft 6 via an annular thrust collar 26 fixed to the outer circumferential surface of the rotating shaft 6, and includes a pair of stationary disks 28 (thrust bearings) arranged to sandwich the thrust collar 26. One of the pair of stationary disks 28 is arranged on one side of the thrust collar 26 in the axial direction, and the other of the pair of stationary disks 28 is arranged on the other side of the thrust collar 26 in the axial direction.

[0018] 1 , the turbocharger 2 includes a compressed air supply line 30 configured to supply compressed air to the back surface 18a of the turbine disk 18, an electric valve 32 provided in the compressed air supply line 30, and a control device 34 configured to control the opening degree of the electric valve 32 based on the thrust load L from the rotating shaft 6 to the thrust bearing 24. In the illustrated exemplary embodiment, the turbocharger 2 includes a compressed air supply source 36 provided outside the turbocharger 3, and the compressed air supply line 30 includes an external compressed air supply path 30A extending from the compressed air supply source 36 to the back surface 18a of the turbine disk 18 so as to supply compressed air from the compressed air supply source 36 to the back surface 18a of the turbine disk 18. In this case, a part of the external compressed air supply path 30A may be configured as a pipe provided outside a casing (not shown) of the turbocharger 3, and the remaining part of the external compressed air supply path 30A may be configured as an internal flow path formed inside the casing of the turbocharger 3. In the illustrated example, the motorized valve 32 is provided in the external compressed air supply path 30A, and a check valve 33 for preventing backflow is provided in the external compressed air supply path 30A downstream of the motorized valve 32. The motorized valve 32 is configured to be able to adjust the flow rate of compressed air supplied from the compressed air supply line 30 to the back surface 18a of the turbine disk 18, and may be, for example, a flow control valve.

[0019] 1, the turbocharger 2 is equipped with a first measuring device 35 that measures a first parameter A1 related to the thrust load L that the thrust bearing 24 receives from the rotating shaft 6, and a second measuring device 37 that measures a second parameter A2 related to the back pressure Pb0 of the turbine disk 18. Hereinafter, the term "thrust load" refers to the thrust load from the rotating shaft 6 to the thrust bearing 24 (the thrust load that the thrust bearing 24 receives from the rotating shaft 6), and the "back pressure" of the turbine disk 18 refers to the pressure of gas acting on the back surface 18a of the turbine disk 18 (the end surface of the turbine disk 18 that faces the compressor 4).

[0020] The first parameter A1 may be, for example, the temperature of the thrust bearing 24, or the temperature difference between the lubricant inlet temperature of the turbocharger 3 (the temperature of the lubricant supplied to the thrust bearing 24 at the inlet of the turbocharger 3) and the lubricant outlet temperature of the turbocharger 3 (the temperature of the lubricant supplied to the thrust bearing 24 at the outlet of the turbocharger 3), i.e., the value obtained by subtracting the lubricant inlet temperature of the turbocharger 3 from the lubricant outlet temperature of the turbocharger 3. When the first parameter A1 is the bearing temperature of the thrust bearing 24, the first measuring device 35 may be a temperature sensor that measures the temperature of the thrust bearing 24. When the first parameter A1 is the temperature difference between the lubricant inlet temperature and the lubricant outlet temperature of the turbocharger 3, the first measuring device 35 may be a temperature sensor (for example, a thermocouple) that measures the temperature difference.

[0021] The second parameter A2 may be, for example, the turbine inlet pressure (the pressure at the exhaust gas inlet of the turbine 5) in the turbocharger 3. In this case, the second measuring device 37 may be a pressure sensor that measures the turbine inlet pressure.

[0022] Next, a method for controlling the motor-operated valve 32 by the control device 34 will be described. Fig. 2 is a diagram showing an example of the hardware configuration of the control device 34. Fig. 3 is a block diagram showing an example of the functional configuration of the control device 34. Fig. 4 is a flow diagram showing an example of the opening control of the motor-operated valve 32 using the control device 34 shown in Fig. 3.

[0023] 2, the control device 34 is configured using a computer that includes, for example, a processor 72, a RAM (Random Access Memory) 74, a ROM (Read Only Memory) 76, a HDD (Hard Disk Drive) 78, an input I / F 80, and an output I / F 82, all of which are connected to one another via a bus 84. The hardware configuration of the control device 34 is not limited to the above, and may be configured using a combination of a control circuit and a storage device. The control device 34 is also configured by a computer executing a program that realizes each function of the control device 34. The functions of each part of the control device 34 described below are realized, for example, by loading a program stored in the ROM 76 into the RAM 74 and executing it with the processor 72, as well as by reading and writing data from and to the RAM 74 and ROM 76.

[0024] As shown in FIG. 3, the control device 34 includes a thrust load estimation unit 40, a thrust load reduction amount calculation unit 42, a back pressure estimation unit 44, a target back pressure calculation unit 46, a supply air amount calculation unit 48, a valve opening control unit 50, and a memory unit 52.

[0025] As shown in FIG. 4, in S101, the thrust load estimation unit 40 estimates the thrust load L based on the measurement value of the first parameter A1 measured by the first measuring device 35 and thrust load correlation information R1 (see FIGS. 5 and 6) indicating the correlation between the first parameter A1 and the thrust load L. The thrust load correlation information R1 is stored in the storage unit 52, and is read out from the storage unit 52 and referenced when estimating the thrust load L in S101. In the example shown in FIG. 5, when the first parameter A1 is the temperature of the thrust bearing 24, the thrust load correlation information R1 indicates the correlation between the temperature of the thrust bearing 24 and the thrust load L, and there is a positive correlation between the temperature of the thrust bearing 24 and the thrust load L. In the example shown in Figure 6, the thrust load correlation information R1 indicates the correlation between the temperature difference and the thrust load L when the first parameter A1 is the temperature difference between the lubricant inlet temperature and the lubricant outlet temperature of the turbocharger 3, and the temperature difference and the thrust load L have a positive correlation.

[0026] In S102, the thrust load reduction amount calculation unit 42 calculates a thrust load reduction amount ΔL, which is a target value for the amount of reduction of the thrust load L, based on the thrust load L estimated by the thrust load estimation unit 40. For example, when the thrust load L estimated by the thrust load estimation unit 40 exceeds a predetermined threshold Lth, the thrust load reduction amount calculation unit 42 calculates the thrust load reduction amount ΔL by subtracting the thrust load threshold Lth from the thrust load L estimated by the thrust load estimation unit 40 (calculating ΔL = L - Lth). Here, the threshold Lth is preset to a value that causes the temperature of the thrust bearing 24 to be equal to or lower than the allowable temperature TL of the thrust bearing 24. For example, as shown in FIG. 7, the efficiency of the turbocharger 3 increases as the thrust load L decreases, and the temperature of the thrust bearing 24 decreases as the thrust load L decreases. Therefore, the thrust load corresponding to the reference temperature Tth, which is set with a margin taken into consideration with respect to the allowable temperature TL, may be set as the threshold value Lth so that the temperature of the thrust bearing 24 is below the allowable temperature TL that is acceptable from the standpoint of the reliability of the thrust bearing 24 (from the standpoint of the risk of damage to the thrust bearing 24).

[0027] In S103, the back pressure estimation unit 44 estimates the back pressure Pb0 of the turbine disk 18 based on the measurement value of the second parameter A2 measured by the second measuring device 37 and back pressure correlation information R2 (see FIG. 8 ) indicating the correlation between the second parameter A2 and the back pressure Pb0 of the turbine disk 18. The back pressure correlation information R2 is stored in the storage unit 52, and is read out from the storage unit 52 and referenced when estimating the back pressure Pb0 of the turbine disk 18 in S103. In the example shown in FIG. 8 , the back pressure correlation information R2 indicates the correlation between the turbine inlet pressure and the back pressure Pb0 of the turbine disk 18 when the second parameter A2 is the turbine inlet pressure, and the turbine inlet pressure and the back pressure Pb0 of the turbine disk 18 have a positive correlation. Note that in the back pressure correlation information R2 shown in FIG. 8 , the ratio of the turbine back pressure to the turbine inlet pressure may be used instead of the turbine back pressure on the vertical axis.

[0028] In S104, the target back pressure calculation unit 46 calculates a target back pressure Pb1, which is a target value of the back pressure of the turbine disk 18 for realizing the thrust load reduction amount ΔL, based on the thrust load reduction amount ΔL calculated by the thrust load reduction amount calculation unit 42 and the back pressure Pb0 of the turbine disk 18 estimated by the back pressure estimation unit 44.

[0029] In S105, the supply air amount calculation unit 48 calculates a supply air amount Q, which is the flow rate of compressed air supplied from the compressed air supply line 30 to the back surface 18a of the turbine disk 18 (the flow rate of the compressed air supply line 30), based on the pressure difference (Pb1-Pb0) between the target back surface pressure Pb1 calculated by the target back surface pressure calculation unit 46 and the back surface pressure Pb0 of the turbine disk 18 estimated by the back surface pressure estimation unit 44. The supply air amount Q calculated here may be a value proportional to the pressure difference (Pb1-Pb0). Then, the valve opening control unit 50 controls the opening of the electric valve 32 so as to realize the supply air amount Q calculated by the supply air amount calculation unit.

[0030] Here, the effects achieved by the supercharger 2 will be described. In the above-described turbocharger 2, the opening degree of the electric valve 32 is controlled based on the thrust load from the rotating shaft 6 to the thrust bearing 24, so the flow rate of compressed air supplied from the compressed air supply line 30 to the back surface 18a of the turbine disk 18 can be adjusted in accordance with the thrust load. As a result, the back surface pressure of the turbine disk 18 can be adjusted in accordance with the thrust load, thereby reducing the thrust load, thereby achieving both improved efficiency of the turbocharger 3 and reliability of the thrust bearing 24 (reducing the risk of damage to the thrust bearing 24 or suppressing an increase in the risk of damage). Furthermore, compared to the configuration described in Patent Document 2, there is no need to provide an electromagnet and an installation space therefor inside the turbocharger 3, so it is possible to suppress an increase in the size of the thrust bearing 24 and the turbocharger 3. Furthermore, compared to the configuration described in Patent Document 2, which requires providing a permanent magnet and an electromagnet inside the turbocharger, it is possible to suppress an increase in the complexity of the configuration of the turbocharger 3.

[0031] Furthermore, in the turbocharger 2, the back pressure of the turbine disk 18 is adjusted by using compressed air from a compressed air supply source 36 provided outside the turbocharger 3, so there is no need to reduce the amount of compressed air supplied from the compressor 4 to an engine (not shown), and it is possible to achieve both improved efficiency of the turbocharger 3 and reliability of the thrust bearing 24.

[0032] Furthermore, in the above-described turbocharger 2, the turbine 5 of the turbocharger 3 is an axial-flow turbine, and therefore the thrust load acting from the rotating shaft 6 on the thrust bearing 24 is in a direction from the turbine 5 side to the compressor 4 side. Therefore, by supplying compressed air from the compressed air supply line 30 to the back surface 18a of the turbine disk 18 as described above, it is possible to reduce the thrust load acting in a direction from the turbine 5 side to the compressor 4 side.

[0033] Furthermore, in the turbocharger 2, the thrust load can be estimated based on the measurement value of the first parameter A1 related to the thrust load and the thrust load correlation information R1, even if a load sensor for measuring the thrust load is not provided in the turbocharger 3. Therefore, even if the load sensor is not provided in the turbocharger 3, by controlling the opening of the electric valve 32 based on the thrust load estimated by the thrust load estimating unit 40, it is possible to achieve both improved efficiency of the turbocharger 3 and reliability of the thrust bearing 24.

[0034] Furthermore, in the turbocharger 2, as the thrust load increases, the temperature of the thrust bearing 24 increases and the temperature difference between the inlet temperature and the outlet temperature of the lubricating oil increases. Therefore, as described above, by using the temperature of the thrust bearing 24 or the temperature difference between the inlet temperature and the outlet temperature of the lubricating oil supplied to the thrust bearing 24 in the turbocharger 3 as the first parameter A1, it is possible to accurately estimate the thrust load based on the measurement value of the first parameter A1 and the thrust load correlation information R1. Therefore, even if the load sensor is not provided in the turbocharger 3, it is possible to achieve both improved efficiency of the turbocharger 3 and reliability of the thrust bearing 24.

[0035] Furthermore, in the supercharger 2, the threshold value Lth of the thrust load is set so that the temperature of the thrust bearing 24 does not exceed the allowable temperature (the upper limit of the temperature of the thrust bearing 24), thereby ensuring the reliability of the thrust bearing 24.

[0036] Moreover, in the turbocharger 2, the control device 34 controls the aperture of the electric valve 32 based on the thrust load reduction amount ΔL calculated by the thrust load reduction amount calculation unit 42 and the back pressure Pb1 of the turbine disk 18 estimated by the back pressure estimation unit 44. Therefore, the aperture of the electric valve 32 for achieving the thrust load reduction amount ΔL can be set in consideration of the back pressure Pb1 of the turbine disk 18, and therefore it is possible to improve the efficiency of the turbocharger 3 and ensure the reliability of the thrust bearing 24 at the same time.

[0037] Furthermore, in the turbocharger 2, the back pressure of the turbine disk 18 can be estimated based on the measurement value of the second parameter A2 related to the back pressure of the turbine disk 18 and the back pressure correlation information R2, even if the turbocharger 3 does not include a pressure sensor for measuring the back pressure of the turbine disk 18. Therefore, even if the turbocharger does not include a pressure sensor for measuring the back pressure of the turbine disk 18, the opening degree of the motor-operated valve 32 for achieving the thrust load reduction amount ΔL can be set in consideration of the back pressure estimated by the back pressure estimation unit 44, thereby achieving both improved efficiency of the turbocharger 3 and reliability of the thrust bearing 24. Note that if a pressure sensor for directly measuring the back pressure of the turbine disk were to be provided in the turbocharger, it would be necessary to drill a hole in the turbocharger for inserting the pressure sensor, which would be difficult to process. In addition, because the back surface of the turbine disk is a relatively hot location, a sensor that can withstand such high temperatures would be required, which would increase costs. For these reasons, it is not easy to provide a pressure sensor for directly measuring the back pressure of the turbine disk.

[0038] Furthermore, in the turbocharger 2, the back pressure of the turbine disk 18 increases as the turbine inlet pressure increases. Therefore, as described above, by using the turbine inlet pressure as the second parameter A2, the back pressure of the turbine disk 18 can be accurately estimated based on the measurement value of the second parameter A2 and the back pressure correlation information R2. Therefore, even if the pressure sensor is not provided in the turbocharger, it is possible to achieve both improved efficiency of the turbocharger 3 and reliability of the thrust bearing 24.

[0039] Furthermore, in the turbocharger 2, the target back pressure Pb1 for realizing the thrust load reduction amount ΔL is calculated taking into consideration the current back pressure Pb0, and the supply air amount Q can be calculated according to the pressure difference between the target back pressure Pb1 and the current back pressure Pb0. Therefore, by controlling the opening of the electric valve 32 so as to realize the calculated supply air amount Q, the thrust force reduction amount ΔL can be realized, and both improvement in the efficiency of the turbocharger 3 and reliability of the thrust bearing 24 can be achieved.

[0040] FIG. 9 is a schematic diagram of a supercharger 2 according to another embodiment. In the supercharger 2 shown in FIG. 9, the symbols common to the components of the supercharger 2 described using FIGS. 1 to 8 indicate the same components as the components of the supercharger 2 described using FIGS. 1 to 8 unless otherwise specified, and the description thereof will be omitted.

[0041] The turbocharger 2 shown in Fig. 9 differs from the turbocharger 2 shown in Fig. 1 in that compressed air generated by the compressor 4 (compressed air generated by passing through the compressor impeller 8) is supplied to the back surface 18a of the turbine disk 18, instead of compressed air from the above-mentioned compressed air supply source 36. The compressed air supply line 30 in the turbocharger 2 shown in Fig. 9 includes a compressor compressed air supply path 30B configured to supply compressed air generated by the compressor 4 to the back surface 18a of the turbine disk 18, instead of the above-mentioned external compressed air supply path 30A.

[0042] 9, the compressor compressed air supply passage 30B extends from the scroll passage 19 (vortex chamber) formed on the outer periphery of the compressor impeller 8 of the compressor 4 to the back surface 18a of the turbine disk 18 so as to bleed compressed air from the scroll passage 19 and supply it to the back surface 18a of the turbine disk 18. In this case, the entire compressor compressed air supply passage 30B may be an internal passage formed inside a casing (not shown) of the turbocharger 3, or a part of the compressor compressed air supply passage 30B may be configured by a pipe provided outside the casing of the turbocharger 3, and the remaining part of the compressor compressed air supply passage 30B may be configured by an internal passage formed inside the casing of the turbocharger 3. In the illustrated example, the motor-operated valve 32 is provided in the compressor compressed air supply passage 30B (compressed air supply line 30), and a check valve 33 for preventing backflow is provided in the compressor compressed air supply passage 30B downstream of the motor-operated valve 32.

[0043] In the supercharging device 2 shown in FIG. 9, the method of controlling the electric valve 32 by the control device 34 is the same as the method of controlling the electric valve 32 by the control device 34 in the supercharging device 2 described using FIGS. 1 to 8, and therefore a description thereof will be omitted.

[0044] According to the turbocharger 2 shown in Fig. 9, the back pressure of the turbine disk 18 is adjusted by using compressed air generated by passing through the compressor impeller 8, thereby achieving both improved efficiency of the turbocharger 3 and reliability of the thrust bearing 24. Therefore, compared to the configuration of the turbocharger 2 shown in Fig. 1 etc., the capacity of the compressed air supply source 36 provided outside the turbocharger 3 can be reduced, or the compressed air supply source 36 can be made unnecessary.

[0045] Here, a comparison of thrust loads and the like according to operating conditions of the turbocharger 3 between the embodiment shown in Fig. 9 and the comparative embodiment shown in Fig. 10 is shown in Fig. 11. The turbocharger 02 in the comparative embodiment shown in Fig. 10 differs from the turbocharger 2 shown in Fig. 9 in that it does not include the electric valve 32, the control device 34 for controlling the electric valve 32, and the like.

[0046] 12, Condition 1 and Condition 2 in Fig. 11 indicate different operating points on the operating line of the compressor 4. Condition 1 is a condition with a lower load than Condition 2, the flow rate of the compressor 4 in Condition 1 is smaller than the flow rate of the compressor 4 in Condition 2, and the pressure ratio of the compressor 4 in Condition 1 is smaller than the pressure ratio of the compressor 4 in Condition 2.

[0047] As shown in FIG. 11 , in the comparative example, the thrust load is larger under condition 2 than under condition 1, whereas in the embodiment, by increasing the aperture of the motor-operated valve 32 under condition 2 compared to condition 1, the amount of air supplied Q to the back surface 18a of the turbine disk 18 is relatively larger and the thrust load is relatively lower. In this way, when the load on the turbocharger 3 is low, the aperture of the motor-operated valve 32 is relatively small to reduce the amount of air bleed from the compressor compressed air supply passage 30B, thereby improving the efficiency of the turbocharger 3. Furthermore, when the load on the turbocharger 3 is low, the absolute value of the thrust load is small, so even if the amount of air supplied Q to the back surface 18a of the turbine disk 18 is reduced, the thrust load does not exceed the allowable value and the risk of damage to the thrust bearing 24 is low. On the other hand, when the load on the turbocharger 3 is high, the thrust load is large. Therefore, by increasing the aperture of the motor-operated valve 32 compared to when the load on the turbocharger 3 is low and increasing the amount of air supplied Q, the thrust load can be reduced and the risk of damage to the thrust bearing 24 can be reduced. Therefore, it is possible to achieve both improved efficiency of the turbocharger 3 and reliability of the thrust bearing 24. Furthermore, compared to the configuration described in Patent Document 2, there is no need to provide an electromagnet and an installation space therefor inside the turbocharger 3, so that it is possible to prevent the turbocharger 3 from becoming large.

[0048] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0049] For example, in the above-described embodiment, the compressed air supply line is configured to supply compressed air to the back surface of the turbine disk. However, if the turbine of the supercharger is a radial turbine, a thrust load in the direction from the compressor to the turbine may act on the thrust bearing. Therefore, the compressed air supply line (external compressed air supply path or compressor compressed air supply path) may be configured to supply compressed air to the back surface of the compressor disk. Furthermore, if the turbine of the turbocharger is a radial turbine, a thrust load may act in the direction from the turbine to the compressor. In such a case, the compressed air supply line (external compressed air supply path or compressor compressed air supply path) may be configured to supply compressed air to the back surface of the turbine disk.

[0050] In addition, in some embodiments, the compressed air supply line for supplying compressed air to the back surface of the turbine disk may include both the external compressed air supply passage described using FIG. 1 and the compressor compressed air supply passage 30B described using FIG. 9.

[0051] In addition, in the above-described embodiment, the electric valve is configured as a flow control valve (variable valve) that can adjust the flow rate of compressed air supplied from the compressed air supply line to the back surface of the turbine disk, but the electric valve may also be an on / off valve.

[0052] In addition, in the embodiment shown in FIG. 9, a compressor compressed air supply passage is exemplified in which compressed air is extracted from the scroll flow passage (vortex chamber) and supplied to the back surface of the turbine disk. However, the compressor compressed air supply passage may be configured to extract compressed air from downstream of the scroll flow passage (for example, between the scroll flow passage and an air cooler (not shown), or between the air cooler and an engine (not shown)) and supply it to the back surface of the turbine disk.

[0053] The contents described in each of the above embodiments can be understood, for example, as follows.

[0054] (1) A supercharger according to at least one embodiment of the present disclosure, A supercharging device (for example, the above-mentioned supercharger 2) including a supercharger (for example, the above-mentioned supercharger 3), The turbocharger is a compressor impeller (e.g., compressor impeller 8 described above) including a compressor disk (e.g., compressor disk 10 described above); a turbine disk (e.g., turbine disk 18 described above); a rotating shaft (for example, the above-mentioned rotating shaft 6) that connects the compressor impeller and the turbine disk; a thrust bearing (for example, the above-mentioned thrust bearing 24) that restricts the axial movement of the rotary shaft; Including, The supercharging device is a compressed air supply line (e.g., compressed air supply line 30 described above) configured to supply compressed air to the back surface of the compressor disk or the back surface of the turbine disk; a valve (such as the valve 32 described above) provided in the compressed air supply line; a control device (for example, the above-described control device 34) configured to control the opening degree of the valve based on a thrust load from the rotating shaft to the thrust bearing; Equipped with.

[0055] According to the turbocharger described in (1) above, the valve opening is controlled based on the thrust load from the rotating shaft to the thrust bearing, so the flow rate of compressed air supplied from the compressed air supply line to the back surface of the turbine disk can be adjusted according to the thrust load. This allows the back surface pressure of the turbine disk to be adjusted according to the thrust load, thereby reducing the thrust load, thereby achieving both improved turbocharger efficiency and increased thrust bearing reliability. Furthermore, compared to the configuration described in Patent Document 2, there is no need to provide an electromagnet and its installation space inside the turbocharger, so the thrust bearing and turbocharger can be kept large. Furthermore, compared to the configuration described in Patent Document 2, which requires the provision of a permanent magnet and an electromagnet inside the turbocharger, the turbocharger can be kept from becoming too complicated in configuration.

[0056] (2) In some embodiments, in the supercharging device described in (1) above, The compressed air supply line includes an external compressed air supply passage (for example, the above-described external compressed air supply passage 30A) configured to supply compressed air from a compressed air supply source provided outside the turbocharger to the back surface of the compressor disk or the back surface of the turbine disk.

[0057] According to the turbocharging device described in (2) above, the back pressure of the compressor disk or the back pressure of the turbine disk is adjusted by using compressed air from a compressed air supply source provided outside the turbocharger, so that the amount of compressed air supplied from the compressor to the engine does not need to be reduced, as compared to the configuration described in (3) below.

[0058] (3) In some embodiments, in the supercharger according to (1) or (2), The compressed air supply line includes a compressor compressed air supply passage (e.g., the above-mentioned compressor compressed air supply passage 30B) configured to supply compressed air generated by passing through the compressor impeller to the back surface of the compressor disk or the back surface of the turbine disk.

[0059] According to the turbocharger described in (3) above, the back pressure of the compressor disk or the back pressure of the turbine disk is adjusted by utilizing compressed air generated by passing through the compressor impeller. Therefore, compared to the configuration in (2) above, the capacity of the compressed air supply source provided outside the turbocharger can be reduced or the supply source can be made unnecessary.

[0060] (4) In some embodiments, in the supercharger device according to any one of (1) to (3), the turbine of the turbocharger (for example, the turbine 5 described above) is an axial flow turbine; The compressed air supply line is configured to supply compressed air to a rear surface of the turbine disk.

[0061] In the turbocharger described in (4) above, the turbine of the turbocharger is an axial-flow turbine, so the thrust force acting from the rotating shaft to the thrust bearing is in the direction from the turbine side to the compressor side. Therefore, by supplying compressed air from the compressed air supply line to the back surface of the turbine disk as described in (4) above, it is possible to reduce the thrust load in the direction from the turbine side to the compressor side.

[0062] (5) In some embodiments, in the supercharger described in (4) above, The control device includes a thrust load estimation unit (e.g., the above-mentioned thrust load estimation unit 40) configured to estimate the thrust load (e.g., the above-mentioned thrust load L) based on a measured value of a first parameter related to the thrust load (e.g., the above-mentioned first parameter A1) and thrust load correlation information (e.g., the above-mentioned thrust load correlation information R1) indicating the correlation between the first parameter and the thrust load, and is configured to control the opening of the valve based on the thrust load estimated by the thrust load estimation unit.

[0063] According to the turbocharger described in (5) above, even if a load sensor for measuring the thrust load is not provided in the turbocharger, the thrust load can be estimated based on the measurement value of the first parameter related to the thrust load and the thrust load correlation information. Therefore, even if the load sensor is not provided in the turbocharger, by controlling the valve opening based on the thrust load estimated by the thrust load estimating unit, it is possible to achieve both improved turbocharger efficiency and reliability of the thrust bearing.

[0064] (6) In some embodiments, in the supercharging device described in (5) above, The first parameter is the temperature of the thrust bearing or the temperature difference between the lubricant inlet temperature and the lubricant outlet temperature of the supercharger.

[0065] As the thrust load increases, the temperature of the thrust bearing increases and the temperature difference between the inlet and outlet temperatures of the lubricating oil increases. Therefore, according to the turbocharger described in (6) above, by using any of these as the first parameter, the thrust load can be accurately estimated based on the measured value of the first parameter and the thrust load correlation information. Therefore, even without providing the load sensor in the turbocharger, it is possible to achieve both improved turbocharger efficiency and reliability of the thrust bearing.

[0066] (7) In some embodiments, in the supercharger according to (5) or (6), The control device is configured to increase the opening of the valve when the thrust load exceeds a threshold value (for example, the above-mentioned threshold value Lth).

[0067] If the temperature of the thrust bearing becomes excessively high, the risk of damage to the thrust bearing increases. Therefore, in the supercharging device described in (7) above, the above threshold value of the thrust load is set so that the temperature of the thrust bearing does not exceed the allowable temperature (upper limit value of the temperature of the thrust bearing), thereby ensuring the reliability of the thrust bearing.

[0068] (8) In some embodiments, in the supercharger according to any one of (5) to (7), The control device includes a thrust load reduction amount calculation unit (e.g., the above-mentioned thrust load reduction amount calculation unit 42) that calculates a thrust load reduction amount (e.g., the above-mentioned thrust load reduction amount ΔL), which is a target value for the amount of thrust load reduction, based on the thrust load, and is configured to control the opening of the valve based on the thrust load reduction amount calculated by the thrust load reduction amount calculation unit and the back pressure of the turbine disk (e.g., the above-mentioned back pressure Pb0).

[0069] According to the turbocharger described in (8) above, the valve opening for realizing the thrust load reduction amount can be set in consideration of the back pressure of the turbine disk, so that it is possible to more effectively achieve both improved turbocharger efficiency and reliability of the thrust bearing.

[0070] (9) In some embodiments, in the supercharging device described above in (8), The thrust load reduction amount calculation unit calculates the thrust load reduction amount so that the temperature of the thrust bearing becomes equal to or lower than an allowable temperature (for example, the above-mentioned allowable temperature TL).

[0071] According to the supercharger described in (9) above, the thrust load reduction amount is determined in consideration of the risk of damage to the thrust bearing so that the temperature of the thrust bearing does not become excessively high, thereby effectively improving the reliability of the thrust bearing.

[0072] (10) In some embodiments, in the supercharger according to (8) or (9), The thrust load reduction amount calculation unit is configured to calculate the thrust load reduction amount by subtracting the threshold value of the thrust load from the thrust load estimated by the thrust load estimation unit when the thrust load exceeds a threshold value (for example, the above-mentioned threshold value Lth).

[0073] According to the supercharger described in (10) above, by setting a threshold value taking into consideration the risk of damage to the thrust bearing, the thrust load reduction amount is determined so that the thrust load does not become excessively large, thereby effectively improving the reliability of the thrust bearing.

[0074] (11) In some embodiments, in the supercharger according to any one of (8) to (10), The control device includes a back pressure estimation unit (e.g., the above-mentioned back pressure estimation unit 44) configured to estimate the back pressure based on a measured value of a second parameter related to the back pressure (e.g., the above-mentioned second parameter A2) and back pressure correlation information (e.g., the above-mentioned back pressure correlation information R2) indicating the correlation between the second parameter and the back pressure, and is configured to control the opening of the valve based on the thrust load reduction amount calculated by the thrust load reduction amount calculation unit and the back pressure estimated by the back pressure estimation unit.

[0075] According to the turbocharger described in (11) above, even if a pressure sensor for measuring the back pressure of the turbine disk is not provided in the turbocharger, the back pressure can be estimated based on the measurement value of the second parameter related to the back pressure and the back pressure correlation information. Therefore, even if a pressure sensor for measuring the back pressure is not provided in the turbocharger, by setting the valve opening for realizing the thrust load reduction amount in consideration of the back pressure estimated by the back pressure estimating unit, it is possible to more effectively achieve both improvement in turbocharger efficiency and reliability of the thrust bearing.

[0076] (12) In some embodiments, in the supercharging device described in (11), The second parameter is a turbine inlet pressure in the supercharger.

[0077] As the turbine inlet pressure increases, the turbine disk back pressure increases. Therefore, by using the turbine inlet pressure as the second parameter as described in (12) above, the turbine disk back pressure can be accurately estimated based on the measurement value of the second parameter and the back pressure correlation information. Therefore, even if the pressure sensor is not provided in the turbocharger, it is possible to achieve both improved turbocharger efficiency and thrust bearing reliability.

[0078] (13) In some embodiments, in the supercharger according to any one of (8) to (12), The control device a target back pressure calculation unit (for example, the above-mentioned target back pressure calculation unit 46) configured to calculate a target back pressure (for example, the above-mentioned target back pressure Pb1) which is a target value of the back pressure for realizing the thrust load reduction amount, based on the thrust load reduction amount calculated by the thrust load reduction amount calculation unit and the back pressure; a supply air amount calculation unit (for example, the above-mentioned supply air amount calculation unit 48) that calculates a supply air amount (for example, the above-mentioned supply air amount Q) that is a flow rate of the compressed air to be supplied from the compressed air supply line to the back surface of the turbine disk based on the target back surface pressure calculated by the target back surface pressure calculation unit; and is configured to control the opening degree of the valve so as to realize the amount of supplied air calculated by the amount of supplied air calculation unit.

[0079] According to the turbocharger described in (13) above, the target back pressure for realizing the thrust load reduction amount is calculated taking into consideration the current back pressure, and the valve opening is controlled so as to realize the amount of supplied air calculated based on the target back pressure, thereby making it possible to effectively reduce the thrust load and to achieve both improved turbocharger efficiency and reliability of the thrust bearing. [Explanation of symbols]

[0080] 2,02 Supercharger 3. Turbocharger 4 Compressor 5 Turbine 6 Rotation Axis 7 Bearing device 8 Compressor impeller 10 Compressor disc 12 Compressor blade 18 Turbine disc 18a back 19 Scroll flow passage 20 Turbine blades 22 Journal bearing 24 Thrust bearing 26 Thrust collar 28 Stationary Disk 30 Compressed air supply line 30A External compressed air supply line 30B Compressor compressed air supply line 32 Electric valve 33 Check valve 34 Control device 35 First Measurement Device 36 Compressed air supply source 37 Second Measurement Device 40 Thrust load estimation section 42 Thrust load reduction calculation section 44 Back pressure estimation section 46 Target back pressure calculation unit 48 Supply air volume calculation section 50 Valve opening control unit 52 Storage section 72 processors 74 RAM 76 ROM 78 HDD 80 input I / F 82 Output I / F 84 Bus A1 First parameter A2 Second parameter L Thrust load Lth threshold Pb0 Back pressure Pb1 Target back pressure Q Air supply volume R1 Thrust load correlation information R2 Back pressure correlation information TL Allowable temperature Tth reference temperature

Claims

1. A supercharging device including a supercharger, The turbocharger is a compressor impeller including a compressor disc; A turbine disc, a rotating shaft connecting the compressor impeller and the turbine disk; a thrust bearing that restricts axial movement of the rotating shaft; Including, The supercharging device is a compressed air supply line configured to supply compressed air to the rear surface of the compressor disk or the rear surface of the turbine disk; a valve provided in the compressed air supply line; a control device configured to control an opening degree of the valve based on a thrust load from the rotating shaft to the thrust bearing; Equipped with the turbine of the turbocharger is an axial flow turbine, the compressed air supply line is configured to supply compressed air to a rear surface of the turbine disk; the control device includes a thrust load estimation unit configured to estimate the thrust load based on a measurement value of a first parameter related to the thrust load and thrust load correlation information indicating a correlation between the first parameter and the thrust load, and is configured to control an opening of the valve based on the thrust load estimated by the thrust load estimation unit, the control device includes a thrust load reduction amount calculation unit that calculates a thrust load reduction amount, which is a target value for an amount of reduction of the thrust load, based on the thrust load, and is configured to control an opening degree of the valve based on the thrust load reduction amount calculated by the thrust load reduction amount calculation unit and a back pressure of the turbine disk, The control device a target back pressure calculation unit configured to calculate a target back pressure, which is a target value of the back pressure for realizing the thrust load reduction amount, based on the thrust load reduction amount calculated by the thrust load reduction amount calculation unit and the back pressure; a supply air amount calculation unit that calculates a supply air amount, which is a flow rate of the compressed air to be supplied from the compressed air supply line to the back surface of the turbine disk, based on the target back surface pressure calculated by the target back surface pressure calculation unit; and configured to control the opening degree of the valve so as to realize the supply air amount calculated by the supply air amount calculation unit. Supercharging device.

2. 2. The turbocharging device according to claim 1, wherein the compressed air supply line includes an external compressed air supply passage configured to supply compressed air from a compressed air supply source provided outside the turbocharger to the back surface of the compressor disk or the back surface of the turbine disk.

3. 2. The supercharging device according to claim 1, wherein the compressed air supply line includes a compressor compressed air supply passage configured to supply compressed air generated by passing through the compressor impeller to a rear surface of the compressor disk or a rear surface of the turbine disk.

4. The supercharging device according to claim 1 , wherein the first parameter is a temperature of the thrust bearing or a temperature difference between a lubricant oil inlet temperature and a lubricant oil outlet temperature of the supercharger.

5. The supercharging device according to claim 1 , wherein the control device is configured to increase the opening of the valve when the thrust load exceeds a threshold value.

6. The supercharger according to claim 1 , wherein the thrust load reduction amount calculation unit calculates the thrust load reduction amount so that the temperature of the thrust bearing is equal to or lower than an allowable temperature.

7. 2. The turbocharger according to claim 1, wherein, when the thrust load exceeds a threshold, the thrust load reduction amount calculation unit calculates the thrust load reduction amount by subtracting the threshold of the thrust load from the thrust load estimated by the thrust load estimation unit.

8. 2. The turbocharging device according to claim 1, wherein the control device includes a back pressure estimating unit configured to estimate the back pressure based on a measured value of a second parameter related to the back pressure and back pressure correlation information indicating a correlation between the second parameter and the back pressure, and is configured to control an aperture of the valve based on the thrust load reduction amount calculated by the thrust load reduction amount calculating unit and the back pressure estimated by the back pressure estimating unit.

9. The supercharging device according to claim 8 , wherein the second parameter is a turbine inlet pressure in the supercharger.

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