Supercharging system

Abstract

To provide a supercharging system that can early detect surging of a compressor in a supercharger.SOLUTION: A supercharging system comprises: a supercharger including a compressor, and a turbine connected to the compressor via a rotation shaft; a pressure sensor for measuring the inlet pressure of the compressor; and a surging detection unit constituted so as to detect the occurrence of surging of the compressor on the basis of the inlet pressure of the compressor measured by the pressure sensor.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a method for suppressing over-speed of a supercharger, in which the rotation speed of the supercharger is monitored and a wastegate valve is opened when the rotation speed exceeds a threshold value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 62-176442 Summary of the Invention [Problem to be solved by the invention]

[0004] In the method described in Patent Document 1, for example, when compressor surging occurs in a high engine speed range or when surging occurs in one of multiple turbochargers, the speed of the turbocharger increases instantaneously, and control to open the wastegate valve cannot be performed in time, which raises the concern that the turbocharger may overspeed. Therefore, in order to prevent the occurrence of overspeed of the turbocharger, it is necessary to detect the occurrence of compressor surging, which is a sign of overspeed of the turbocharger, at an early stage.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure has an object to provide a supercharging system that can detect the occurrence of compressor surging in a supercharger at an early stage. [Means for solving the problem]

[0006] In order to achieve the above object, a supercharging system according to at least one embodiment of the present disclosure includes: a supercharger including a compressor and a turbine connected to the compressor via a rotary shaft; a pressure sensor for measuring the inlet pressure of the compressor; a surge detection unit configured to detect the occurrence of surging of the compressor based on the inlet pressure of the compressor measured by the pressure sensor; Equipped with. [Effects of the Invention]

[0007] According to at least one embodiment of the present disclosure, a supercharging system capable of detecting the occurrence of compressor surging in a supercharger at an early stage is provided. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram schematically illustrating a configuration of a supercharging system 2 according to an embodiment of the present disclosure. [Figure 2] 1 is a schematic cross-sectional view showing a part of a cross section of a turbocharger 10 taken along an axial direction. [Figure 3] FIG. 2 is a diagram illustrating an example of a hardware configuration of a control device 22. [Figure 4] 2 is a block diagram showing an example of the functional configuration of a control device 22. FIG. [Figure 5] FIG. 3 is a diagram showing an example of a control flow of a control device 22. [Figure 6] 10 is a diagram showing the air flow when surging of the compressor 24 occurs. FIG. [Figure 7] 6 is a diagram showing an example of changes over time in the rotation speed and inlet pressure P of the turbocharger 10 in the case where the control shown in FIG. 5 is not performed in the turbocharging system 2. FIG. [Figure 8] FIG. 8 is a diagram showing the time-dependent changes in the rotation speed of the turbocharger 10 and the inlet pressure change rate dP / dt in the same period as that shown in FIG. 7 when the control shown in FIG. 5 is not performed in the turbocharging system 2. [Figure 9] FIG. 10 is a diagram showing another example of a method for installing the pressure sensor 52, and is a schematic cross-sectional view showing a part of a cross section along the axial direction of the turbocharger 10. [Figure 10]FIG. 10 is a diagram showing yet another example of a method for installing the pressure sensor 52, and is a schematic cross-sectional view showing a part of a cross section along the axial direction of the turbocharger 10. DETAILED DESCRIPTION OF THE INVENTION

[0009] 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.

[0010] FIG. 1 is a diagram schematically illustrating the configuration of a supercharging system 2 according to an embodiment of the present disclosure. As shown in FIG. 1, the turbocharging system 2 includes an engine 4, an air intake line 6, an exhaust line 8, a turbocharger 10, an air bypass line 14, an air bypass valve 16, a wastegate line 18, a wastegate valve 20, and a control device 22.

[0011] The engine 4 burns fuel using air (compressed air) supplied from an air intake line 6, and discharges the generated combustion gas into an exhaust line 8 as exhaust gas.

[0012] The turbocharger 10 includes a compressor 24 provided in the intake line 6, a turbine 26 provided in the exhaust line 8, and a rotary shaft 28 connecting the compressor 24 and the turbine 26.

[0013] The compressor 24 is a centrifugal compressor that compresses air to generate compressed air and supplies the compressed air to the engine 4 via the air intake line 6. Exhaust gas discharged from the engine 4 is supplied to the turbine 26 through the exhaust line 8 to drive the turbine 26, and the rotational energy of the turbine 26 is transmitted to the compressor 24 via the rotary shaft 28, causing the compressor 24 to compress the air.

[0014] The air bypass line 14 branches off from the air intake line 6 and is configured to discharge a portion of the air flowing through the air intake line 6 without supplying it to the engine 4. The air bypass line 14 may also be configured to discharge a portion of the air from the air intake line 6, for example, to the atmosphere. An air bypass valve 16 is provided in the air bypass line 14, and when the air bypass valve 16 is opened, a portion of the air flowing through the air intake line 6 is discharged from the air bypass line 14 without being supplied to the engine 4.

[0015] The wastegate line 18 branches off from the upstream side of the turbine 26 in the exhaust line 8, bypasses the turbine 26, and connects to the downstream side of the turbine 26 in the exhaust line 8. A wastegate valve 20 is provided in the wastegate line 18, and when the wastegate valve 20 is opened, some of the air flowing through the exhaust line 8 passes through the wastegate line 18 (i.e., bypasses the turbine 26) and is supplied to the downstream side of the turbine 26 in the exhaust line 8.

[0016] The control device 22 is configured to control the engine 4 and also to control the valve opening degree of the air bypass valve 16 and the valve opening degree of the wastegate valve 20.

[0017] FIG. 2 is a schematic cross-sectional view showing a part of the cross section of the turbocharger 10 taken along the axial direction. 2, the turbocharger 10 includes a silencer 30 provided at the inlet 24a of the compressor 24. The compressor 24 includes an impeller 32 and a compressor housing 34 that houses the impeller 32. In the illustrated exemplary embodiment, the compressor housing 34 includes a substantially cylindrical air guide cylinder 36 that houses the impeller 32, and a scroll casing 40 that forms a scroll flow passage 38 on the outer circumferential side of the impeller 32, and a flange 31 formed on the silencer 30 and a flange 37 formed on the air guide cylinder 36 are fastened together by a plurality of bolts 41 (a plurality of fastening members).

[0018] In the exemplary form shown in FIG. 2, the silencer 30 includes a disk-shaped first side wall 42 (outer wall of the silencer 30) extending in a direction perpendicular to the rotation axis O of the impeller 32, an annular second side wall 46 provided around the rotation axis O of the impeller 32 between the first side wall 42 and the compressor 24 and forming an outside air introduction space 44 (internal space of the silencer 30) between the first side wall 42 and the second side wall 46 for guiding outside air (air) into the air guide cylinder 36, and an annular flange 31 provided on the second side wall 46.

[0019] 2, the silencer 30 includes at least one silencer element 48 provided in the outside air introduction space 44. In the illustrated example, the silencer 30 includes a silencer element 48 arranged along the inner surface of the first side wall 42, an annular silencer element 48 arranged along the inner surface of the second side wall 46, and a plurality of annular silencer elements 48 arranged at intervals in the direction of the rotation axis O between the first side wall 42 and the second side wall 46. In addition, bolts 90 that penetrate the first side wall 42, each of the silencer elements 48, the second side wall 46, and the flange 31 in the direction of the rotation axis O, and nuts 91 fastened to the bolts 90 are provided at a plurality of locations in the circumferential direction.

[0020] 2, when the impeller 32 of the compressor 24 rotates, outside air is taken into the outside air introduction space 44 from the outer circumferential side of the silencer 30. The flow of outside air taken into the outside air introduction space 44 passes through the silencer element 48, then turns in the direction of the rotation axis O, passes through the inner circumferential side of the annular second side wall 46, and is guided to the air guide cylinder 36.

[0021] In the exemplary embodiment shown in FIG. 2 , the silencer 30 includes a cleaning nozzle 50 for spraying cleaning liquid and a pressure sensor 52 connected to the cleaning nozzle 50 via a cylindrical connector 51 serving as a connecting member. The cleaning nozzle 50 is attached to a through-hole 54 (nozzle insertion hole) formed in the first side wall 42, and a tip 50a of the cleaning nozzle 50 is inserted through the through-hole 54 and disposed in the outside air introduction space 44 (internal space of the silencer 30) of the silencer 30. In the illustrated example, the tip 50a of the cleaning nozzle 50 is disposed on the rotation axis O of the impeller 32 so as to spray cleaning liquid toward the impeller 32. One end of a connector 51 is connected (fitted) to a base end 50b of the cleaning nozzle 50, and a pressure sensor 52 is connected (fitted) to the other end of the connector 51. That is, the pressure sensor 52 is attached to the through-hole 54 via the connector 51 and the cleaning nozzle 50. In this case, the internal space 51s of the connector 51 communicates with the outside air introduction space 44 of the silencer 30 via the internal space 50s of the cleaning nozzle 50 (nozzle flow path of the cleaning nozzle 50), and the pressure sensor 52 faces the internal space 51s of the connector 51. In this case, the pressure sensor 52 measures the pressure in the internal space 51s of the connector 51, i.e., the pressure in the outside air introduction space 44 of the silencer 30, as the inlet pressure P of the compressor 24. Note that the inlet pressure P of the compressor 24 measured by the pressure sensor 52 may be a gauge pressure, which is the differential pressure from atmospheric pressure, or may be an absolute pressure.

[0022] Fig. 3 is a diagram showing an example of the hardware configuration of the control device 22. Fig. 4 is a block diagram showing an example of the functional configuration of the control device 22. Fig. 5 is a diagram showing an example of the control flow of the control device 22.

[0023] 3, the control device 22 is configured using a computer including, for example, a processor 72, a RAM (Random Access Memory) 74, a ROM (Read Only Memory) 76, an HDD (Hard Disk Drive) 78, an input I / F 80, and an output I / F 82, which are connected to one another via a bus 84. The control device 22 is configured by the computer executing a program that realizes each function of the control device 22. The functions of each part of the control device 22 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 the ROM 76. The hardware that makes up the control device 22 may be concentrated in one location or may be distributed across multiple locations.

[0024] 4, the control device 22 includes a surging detection unit 60, an engine control unit 62, an air bypass valve control unit 64, and a wastegate valve control unit 66. The surging detection unit 60 includes an inlet pressure change rate calculation unit 68. The function of each unit of the control device 22 will be described below with reference to FIG. 5.

[0025] 5, in S101, the surging detection unit 60 sequentially acquires the inlet pressure P of the compressor 24, which is measured by the pressure sensor 52 from time to time, from the pressure sensor 52. In S102, the inlet pressure change rate calculation unit 68 sequentially calculates the inlet pressure change rate dP / dt, which is the time change rate of the inlet pressure P. Here, the inlet pressure change rate dP / dt means the amount of change in the inlet pressure P per unit time, i.e., the time derivative value of the inlet pressure P.

[0026] In S103, the surging detection unit 60 compares the inlet pressure change rate dP / dt calculated by the inlet pressure change rate calculation unit 68 with a threshold value Th, and determines whether the inlet pressure change rate dP / dt is below the threshold value Th. If the surging detection unit 60 determines in S103 that the inlet pressure change rate dP / dt calculated by the inlet pressure change rate calculation unit 68 is below the threshold value Th, the surging detection unit 60 detects the occurrence of surging in the compressor 24, which is a sign of overspeed of the turbocharger 10 (i.e., determines that surging in the compressor 24 is occurring), and proceeds to S104.

[0027] In S103, if the surging detection unit 60 determines that the inlet pressure change rate dP / dt calculated by the inlet pressure change rate calculation unit 68 is not below the threshold value Th, the surging detection unit 60 does not detect the occurrence of surging in the compressor 24 (i.e., determines that surging in the compressor 24 is not occurring), and returns to S101.

[0028] In S104, the control device 22 executes control to suppress an increase in the rotation speed of the turbocharger 10. In S104, as control to suppress an increase in the rotation speed of the turbocharger 10, the control device 22 may, for example, reduce the load on the engine 4 using the engine control unit 62, or may stop the operation of the engine 4 using the engine control unit 62. Here, the control to reduce the load on the engine 4 may, for example, be control to reduce the fuel flow rate of the engine 4. In S104, as control to suppress an increase in the rotation speed of the turbocharger 10, the control device 22 may, for example, increase the valve opening degree of the air bypass valve 16 using the air bypass valve control unit 64. In S104, as control to suppress an increase in the rotation speed of the turbocharger 10, the control device 22 may, for example, increase the valve opening degree of the wastegate valve 20 using the wastegate valve control unit 66. In addition, in S104, the control device 22 may execute a combination of any two or more of the following controls to suppress an increase in the rotation speed of the turbocharger 10: control to reduce the load on the engine 4, control to increase the valve opening of the air bypass valve 16, and control to increase the valve opening of the wastegate valve 20.

[0029] Here, the relationship between the surging of the compressor 24 in the turbocharger 10, the inlet pressure P, and the inlet pressure change rate dP / dt will be described with reference to FIGS. Fig. 6 is a diagram showing the air flow when surging occurs in the compressor 24. As shown in Fig. 6, when surging occurs in the compressor 24, compressed air flows back from the downstream side of the compressor 24 in the air supply line 6 toward the suction side of the silencer 30.

[0030] Fig. 7 is a diagram showing an example of changes over time in the rotation speed of the turbocharger 10 and the inlet pressure P when the control shown in Fig. 5 is not performed in the turbocharging system 2. Fig. 8 is a diagram showing changes over time in the rotation speed of the turbocharger 10 and the inlet pressure change rate dP / dt during the same period as that shown in Fig. 7 when the control shown in Fig. 5 is not performed in the turbocharging system 2.

[0031] 7 and 8, surging occurs in the compressor 24 of the turbocharger 10 at time t1, and immediately after the occurrence of surging, compressed air flowing back to the outlet side of the impeller 32 of the compressor 24 acts to inhibit the rotation of the impeller 32, so the rotation speed of the turbocharger 10 temporarily decreases as shown by arrow a1, but during the period thereafter when the air flow returns from reverse flow to forward flow, the compression work of the impeller 32 decreases, so the rotation speed of the turbocharger 10 suddenly increases as shown by arrow a2. Meanwhile, it can be confirmed that the inlet pressure P and the inlet pressure change rate dP / dt change significantly in the negative direction immediately after the occurrence of surging.

[0032] Therefore, as in the above-described turbocharging system 2, by providing a surging detection unit 60 configured to detect the occurrence of surging of the compressor 24 based on the inlet pressure P of the compressor 24, it is possible to detect surging of the compressor 24 in the turbocharger 10 at an early stage. Furthermore, although the inlet pressure P changes depending on the rotation speed of the turbocharger 10, the surging detection unit 60 detects the occurrence of surging of the compressor 24 when the inlet pressure change rate dP / dt falls below the threshold value Th. Therefore, even if the inlet pressure P changes due to the rotation speed of the turbocharger 10, it is possible to accurately detect the occurrence of surging of the compressor 24 at an early stage and to suppress erroneous detection of the occurrence of surging. In addition, when the surging detection unit 60 detects the occurrence of surging in the compressor 24, control is performed to suppress an increase in the rotation speed of the turbocharger 10 (control to reduce the load on the engine 4 or stop the engine 4, control to increase the opening of the air bypass valve 16, or control to increase the opening of the wastegate valve 20), thereby making it possible to suppress over-rotation of the turbocharger 10.

[0033] Fig. 9 is a diagram showing another example of a method for installing the pressure sensor 52, and is a schematic cross-sectional view showing a part of a cross section along the axial direction of the turbocharger 10. In the embodiment shown in Fig. 9, reference numerals common to the respective components of the embodiment shown in Fig. 2 etc. indicate the same components as those of the embodiment shown in Fig. 2 etc. unless otherwise specified, and description thereof will be omitted.

[0034] 9 , one end of a tube 53 serving as a connecting member is connected (fitted) to the base end 50b of the cleaning nozzle 50, and a pressure sensor 52 is connected (fitted) to the other end of the tube 53. That is, the pressure sensor 52 is attached to a through-hole 54 in the first side wall 42 of the silencer 30 via the tube 53 and the cleaning nozzle 50. In this case, the internal space 53s of the tube 53 communicates with the outside air introduction space 44 of the silencer 30 via the internal space 50s of the cleaning nozzle 50 (nozzle flow path of the cleaning nozzle 50), and the pressure sensor 52 faces the internal space 53s of the tube 53. In this case, the pressure sensor 52 measures the pressure in the internal space 53s of the tube 53, i.e., the pressure in the outside air introduction space 44 of the silencer 30, as the inlet pressure P of the compressor 24.

[0035] Fig. 10 is a diagram showing yet another example of a method for installing the pressure sensor 52, and is a schematic cross-sectional view showing a part of a cross section along the axial direction of the turbocharger 10. In the embodiment shown in Fig. 10, reference numerals common to the respective components of the embodiment shown in Fig. 2 etc. indicate the same components as those of the embodiment shown in Fig. 2 etc. unless otherwise specified, and description thereof will be omitted.

[0036] 10 , the pressure sensor 52 may be attached directly to the through-hole 54 in the first side wall 42 of the silencer 30. For example, if a cleaning nozzle 50 (see FIG. 2) is attached to the through-hole 54 (cleaning nozzle insertion hole), the pressure sensor 52 may be attached to the through-hole 54 after the cleaning nozzle 50 is removed from the through-hole 54. In the embodiment shown in FIG. 10 , the pressure sensor 52 is located upstream of the inlet 24 a of the air guide cylinder 36 in the air flow direction, faces the outside air introduction space 44 of the silencer 30, and measures the pressure in the outside air introduction space 44 of the silencer 30 as the inlet pressure P of the compressor 24.

[0037] 9 and the embodiment shown in FIG. 10 also include a surging detection unit 60 configured to detect the occurrence of surging of the compressor 24 based on the inlet pressure P of the compressor 24, thereby enabling early detection of surging of the compressor 24 in the turbocharger 10. Furthermore, by detecting the occurrence of surging of the compressor 24 when the inlet pressure change rate dP / dt falls below the threshold value Th, it is possible to early and accurately detect the occurrence of surging of the compressor 24, and suppress erroneous detection of the occurrence of surging. Furthermore, when the surging detection unit 60 detects the occurrence of surging of the compressor 24, it is possible to suppress the occurrence of overspeed of the turbocharger 10 by performing control to suppress an increase in the rotation speed of the turbocharger 10 (control to reduce the load on the engine 4 or stop the engine 4, control to increase the opening of the air bypass valve 16, or control to increase the opening of the wastegate valve 20).

[0038] 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.

[0039] For example, in some embodiments, the surge detection unit 60 may detect the occurrence of surging when the inlet pressure P of the compressor 24 falls below a threshold value. In this case, the threshold value may be changed depending on the rotation speed of the turbocharger 10.

[0040] Furthermore, in the above-described embodiment, the turbocharger 10 including the silencer 30 has been exemplified, but the turbocharger of the present disclosure does not have to include a silencer. In this case, the pressure sensor 52 may be provided at the inlet of the air guide cylinder 36 of the compressor 24, or, if there is a pipe upstream of the air guide cylinder 36 of the compressor 24, the pressure sensor 52 may be provided in that pipe.

[0041] The contents described in each of the above embodiments can be understood, for example, as follows.

[0042] [1] A supercharging system according to at least one embodiment of the present disclosure (e.g., the supercharging system 2 described above) includes: A turbocharger (for example, the above-mentioned turbocharger 10) including a compressor (for example, the above-mentioned compressor 24) and a turbine (for example, the above-mentioned turbine 26) connected to the compressor via a rotary shaft; a pressure sensor (e.g., the pressure sensor 52 described above) for measuring the inlet pressure of the compressor (e.g., the inlet pressure P described above); a surge detection unit (for example, the above-mentioned surge detection unit 60) configured to detect the occurrence of surging of the compressor based on the inlet pressure of the compressor (for example, the above-mentioned inlet pressure P) measured by the pressure sensor; Equipped with.

[0043] According to the supercharging system described in [1] above, when compressor surging, which is a sign of overspeed of the supercharger, occurs, the occurrence of the surging can be detected early based on the inlet pressure of the compressor. Therefore, when the occurrence of the surging is detected, for example, by performing control to suppress an increase in the rotation speed of the supercharger, the occurrence of overspeed of the supercharger can be suppressed.

[0044] [2] In some embodiments, in the supercharging system described in [1] above, the surging detection unit includes an inlet pressure change rate calculation unit (for example, the above-mentioned inlet pressure change rate calculation unit 68) configured to calculate an inlet pressure change rate (for example, the above-mentioned inlet pressure change rate dP / dt) which is a time change rate of the inlet pressure, The surging detection unit is configured to detect the occurrence of the surging of the compressor when the inlet pressure change rate calculated by the inlet pressure change rate calculation unit falls below a threshold value (for example, the above-mentioned threshold value Th).

[0045] The inlet pressure of the compressor changes depending on the rotation speed of the turbocharger. However, according to the turbocharging system described in [2] above, even if the inlet pressure changes due to the rotation speed of the turbocharger, the occurrence of compressor surging can be detected early and accurately, and false detection of the occurrence of surging can be suppressed.

[0046] [3] In some embodiments, in the supercharging system described in [1] or [2] above, a silencer (e.g., silencer 30 described above) attached to the inlet of the compressor; The pressure sensor is positioned facing the internal space of the silencer (for example, the above-mentioned external air intake space 44) or a space communicating with the internal space of the silencer (for example, the internal space 51s of the above-mentioned connector 51 or the internal space 53s of the tube 53).

[0047] According to the supercharging system described in [3] above, the influence on the air flow inside the compressor can be reduced compared to, for example, a case where a pressure sensor is provided in the compressor, and a decrease in compressor efficiency can be suppressed.

[0048] [4] In some embodiments, in the supercharging system described in [3] above, A through hole (for example, the above-mentioned through hole 54) is formed in the outer wall of the silencer, The pressure sensor is attached to the through hole in the outer wall of the silencer.

[0049] According to the supercharging system described in [4] above, the influence on the air flow inside the compressor can be reduced compared to when a pressure sensor is provided in the compressor, and the decrease in compressor efficiency can be suppressed.

[0050] [5] In some embodiments, in the supercharging system described in [4] above, The through-hole is a nozzle insertion hole for inserting a cleaning nozzle (for example, the above-mentioned cleaning nozzle 50) that sprays cleaning liquid.

[0051] According to the supercharging system described in [5] above, in addition to the effect described in [4] above, the pressure sensor can be attached to the outer wall of the silencer by utilizing the nozzle insertion hole.

[0052] [6] In some embodiments, in the supercharging system described in [3] above, Further provided is a cleaning nozzle (for example, the above-mentioned cleaning nozzle 50) for injecting a cleaning liquid into the inside of the compressor; a through-hole (for example, the above-mentioned through-hole 54) is formed in an outer wall (for example, the above-mentioned first side wall 42) of the silencer, the cleaning nozzle is inserted into the through-hole in the outer wall of the silencer, The pressure sensor is connected to the cleaning nozzle.

[0053] According to the supercharging system described in [6] above, the pressure sensor described in [3] above can be provided without removing the cleaning nozzle.

[0054] [7] In some embodiments, in the supercharging system according to any one of [1] to [6] above, An engine control unit (for example, the above-mentioned engine control unit 62) for controlling an engine connected to the supercharger is further provided, When the surging detection unit detects the occurrence of the surging of the compressor, the engine control unit is configured to reduce the load on the engine or stop the engine.

[0055] According to the supercharging system described in [7] above, when compressor surging, which is a sign of supercharger overspeed, occurs, the surging can be detected early and the engine load can be reduced or the engine can be stopped, thereby preventing the occurrence of supercharger overspeed.

[0056] [8] In some embodiments, in the supercharging system according to any one of [1] to [7] above, an intake line (for example, the intake line 6) that supplies air discharged from the compressor to the engine; an air bypass valve (e.g., the air bypass valve 16 described above) for venting a portion of the air from the air intake line without supplying it to the engine; an air bypass valve control unit (for example, the above-described air bypass valve control unit 64) configured to increase the valve opening of the air bypass valve when the surging detection unit detects the occurrence of the surging of the compressor; Further provided with:

[0057] According to the supercharging system described in [8] above, when compressor surging, which is a sign of overspeed of the supercharger, occurs, the surging can be detected early and some of the air can be released without being supplied to the engine, thereby preventing overspeed of the supercharger.

[0058] [9] In some embodiments, in the supercharging system according to any one of [1] to [8] above, an exhaust line (e.g., the aforementioned exhaust line 8) supplying engine exhaust gas to the turbine; a wastegate line (for example, the above-mentioned wastegate line 18) that branches off from the upstream side of the turbine in the exhaust line and connects to the downstream side of the turbine in the exhaust line; a wastegate valve (for example, the wastegate valve 20 described above) provided in the wastegate line; a wastegate valve control unit (for example, the above-described wastegate valve control unit 66) configured to increase the valve opening of the wastegate valve when the surging detection unit detects the occurrence of the surging of the compressor; Further provided with:

[0059] According to the supercharging system described in [9] above, when compressor surging, which is a sign of overspeed of the supercharger, occurs, the surging can be detected early and the amount of exhaust gas supplied to the turbine can be reduced, thereby suppressing the occurrence of overspeed of the supercharger. [Explanation of symbols]

[0060] 2. Supercharging system 4 Engine 6 Air supply line 8 Exhaust line 10. Turbocharger 14 Air bypass line 16 Air Bypass Valve 18 Wastegate Line 20 Wastegate valve 22 Control device 24 Compressor 24a Entrance 26 Turbine 28 Rotation axis 30 silencer 31,37 Flange 32 impeller 34 Compressor housing 36 Air guide tube 38 Scroll flow passage 40 Scroll casing 41 volts 42 First side wall 44 Outside air intake space 46 Second side wall 48 Silencer element 50 cleaning nozzle 50a tip 50b Proximal end 51 Connector 52 Pressure Sensor 53 tubes 54 Through hole 60 Surging detection unit 62 Engine control unit 64 Air bypass valve control section 66 Wastegate valve control unit 68 Inlet pressure change rate calculation section 72 processors 74 RAM 76 ROM 78 HDD 80 input I / F 82 Output I / F 84 Bus 90 volts 91 Nut O Rotation axis P inlet pressure Th threshold a1, a2 arrows dS / dt Inlet pressure change rate t1 time

Claims

1. a supercharger including a compressor and a turbine connected to the compressor via a rotary shaft; a pressure sensor for measuring the inlet pressure of the compressor; a surge detection unit configured to detect the occurrence of surging of the compressor based on the inlet pressure of the compressor measured by the pressure sensor; A supercharging system comprising:

2. the surging detection unit includes an inlet pressure change rate calculation unit configured to calculate an inlet pressure change rate that is a time change rate of the inlet pressure, 2. The supercharging system according to claim 1, wherein the surging detection unit is configured to detect the occurrence of the surging of the compressor when the inlet pressure change rate calculated by the inlet pressure change rate calculation unit falls below a threshold value.

3. a silencer attached to the inlet of the compressor; The supercharging system according to claim 1 , wherein the pressure sensor is disposed facing the internal space of the silencer or a space communicating with the internal space of the silencer.

4. a through hole is formed in the outer wall of the silencer, The supercharging system according to claim 3 , wherein the pressure sensor is attached to the through-hole in the outer wall of the silencer.

5. The supercharging system according to claim 4, wherein the through-hole is a nozzle insertion hole for inserting a cleaning nozzle that sprays a cleaning liquid.

6. Further provided with a cleaning nozzle for spraying a cleaning liquid, a through hole is formed in the outer wall of the silencer, the cleaning nozzle is inserted into the through-hole in the outer wall of the silencer, The supercharging system according to claim 3 , wherein the pressure sensor is connected to the cleaning nozzle.

7. An engine control unit for controlling an engine connected to the supercharger is further provided, 2. The supercharging system according to claim 1, wherein when the surging detection unit detects the occurrence of the surging of the compressor, the engine control unit is configured to reduce a load on the engine or stop the engine.

8. an air intake line that supplies air discharged from the compressor to an engine; an air bypass valve for discharging a portion of the air from the air intake line without supplying it to the engine; an air bypass valve control unit configured to increase a valve opening degree of the air bypass valve when the surging detection unit detects the occurrence of the surging of the compressor; The supercharging system of claim 1 further comprising:

9. an exhaust line supplying engine exhaust gas to the turbine; a wastegate line branching from the exhaust line on the upstream side of the turbine and connecting to the exhaust line on the downstream side of the turbine; a wastegate valve provided in the wastegate line; a wastegate valve control unit configured to increase a valve opening degree of the wastegate valve when the surging detection unit detects the occurrence of the surging of the compressor; The supercharging system of claim 1 further comprising:

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