Supercharging system

Abstract

The present invention comprises: 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; and a surging detection unit configured to detect the occurrence of surging in the compressor on the basis of the inlet pressure of the compressor measured by the pressure sensor.

Description

Supercharging system

[0001] This application claims priority to Japanese Patent Application No. 2024-060416, filed with the Japan Patent Office on April 3, 2024, the contents of which are incorporated herein by reference.

[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.

[0003] Japanese Utility Model Application Publication No. 62-176442

[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 rotation 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.

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

[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.

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

[0009] Several embodiments of the present disclosure will be described below 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 arrangements, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," not only strictly express such arrangements, but also express relative displacements with a tolerance or angle or distance to the extent that the same function is achieved. For example, expressions expressing the equality of things, such as "same," "equal," and "homogeneous," not only express strict equality, but also express tolerance or differences to the extent that the same function is achieved. For example, expressions expressing shapes such as a square or cylindrical shape not only express shapes such as a square or cylindrical shape in the strict geometric sense, but also express shapes including concave and convex portions, chamfered portions, etc., to the extent that the same effect is achieved. 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] 1 is a diagram schematically illustrating a configuration of a turbocharging 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 as exhaust gas into an exhaust line 8.

[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 rotating 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 exhaust line 8 on the upstream side of the turbine 26, bypasses the turbine 26, and connects to the exhaust line 8 on the downstream side of the turbine 26. 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 exhaust line 8 on the downstream side of the turbine 26.

[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 portion of a cross section taken along the axial direction of the turbocharger 10. As shown in Fig. 2, the turbocharger 10 includes a silencer 30 provided at an inlet 24a of a 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 that is provided around the rotation axis O of the impeller 32 between the first side wall 42 and the compressor 24 and forms an outside air introduction space 44 (internal space of the silencer 30) between the first side wall 42 and the second side wall 46 to introduce outside air (air) into the air guide tube 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 pass through 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 end 50 a 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 end 50 a 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 50 b 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 a 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] As shown in FIG. 3 , the control device 22 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 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] As shown in Fig. 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 measured by the pressure sensor 52 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 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 Figures 6 to 8. Figure 6 is a diagram showing the air flow when surging of the compressor 24 occurs. As shown in Figure 6, when surging of the compressor 24 occurs, compressed air flows back from the downstream side of the compressor 24 in the air intake line 6 toward the suction side of the silencer 30.

[0030] Fig. 7 is a diagram showing an example of the time-dependent changes 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 the time-dependent changes 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 that are common to the respective components of the embodiment shown in Fig. 2 etc. indicate the same components as the respective components 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 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 detect the occurrence of surging of the compressor 24 early and accurately, and to 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 turbocharging system according to at least one embodiment of the present disclosure (for example, the above-described turbocharging system 2) includes: a turbocharger (for example, the above-described turbocharger 10) including a compressor (for example, the above-described compressor 24) and a turbine (for example, the above-described turbine 26) connected to the compressor via a rotating shaft; a pressure sensor (for example, the above-described pressure sensor 52) for measuring an inlet pressure of the compressor (for example, the above-described inlet pressure P); and a surging detection unit (for example, the above-described surging 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-described inlet pressure P) measured by the pressure sensor.

[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 (e.g., the above-mentioned inlet pressure change rate calculation unit 68) configured to calculate an inlet pressure change rate that is a time change rate of the inlet pressure (e.g., the above-mentioned inlet pressure change rate dP / dt), and 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 (e.g., 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, the supercharging system described in [1] or [2] above further comprises a silencer (e.g., the silencer 30 described above) attached to the inlet of the compressor, and the pressure sensor is arranged facing an internal space of the silencer (e.g., the external air introduction space 44 described above) or a space communicating with the internal space of the silencer (e.g., the internal space 51s of the connector 51 or the internal space 53s of the tube 53 described above).

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

[0048] [4] In some embodiments, in the supercharging system described in [3] above, a through hole (e.g., the above-mentioned through hole 54) is formed in the outer wall of the silencer, and 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 a decrease in compressor efficiency can be suppressed.

[0050] [5] In some embodiments, in the turbocharging 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, the turbocharging system described in [3] above further comprises a cleaning nozzle (e.g., the above-mentioned cleaning nozzle 50) for injecting cleaning liquid into the inside of the compressor, a through-hole (e.g., the above-mentioned through-hole 54) is formed in an outer wall of the silencer (e.g., the above-mentioned first side wall 42), the cleaning nozzle is inserted into the through-hole in the outer wall of the silencer, and 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, the supercharging system according to any one of [1] to [6] above further comprises an engine control unit (for example, the above-mentioned engine control unit 62) for controlling an engine connected to the supercharger, and when the surging detection unit detects the occurrence of 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 overspeed of the supercharger, occurs, the surging can be detected early and the engine load can be reduced or the engine can be stopped, thereby suppressing the occurrence of overspeed of the supercharger.

[0056] [8] In some embodiments, the supercharging system according to any one of [1] to [7] above further comprises: an air intake line (for example, the above-mentioned air intake line 6) that supplies air discharged from the compressor to an engine; an air bypass valve (for example, the above-mentioned air bypass valve 16) that releases part of the air from the air intake line without supplying it to the engine; and an air bypass valve control unit (for example, the above-mentioned air bypass valve control unit 64) that is configured to increase the valve opening of the air bypass valve when the surging detection unit detects the occurrence of surging in the compressor.

[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 suppressing overspeed of the supercharger.

[0058] [9] In some embodiments, the turbocharging system according to any one of [1] to [8] above further includes an exhaust line (for example, the above-mentioned exhaust line 8) that supplies engine exhaust gas to the turbine; a wastegate line (for example, the above-mentioned wastegate line 18) that branches off from the exhaust line upstream of the turbine and connects to the exhaust line downstream of the turbine; a wastegate valve (for example, the above-mentioned wastegate valve 20) that is provided in the wastegate line; and a wastegate valve control unit (for example, the above-mentioned wastegate valve control unit 66) that is configured to increase the valve opening of the wastegate valve when the surging detection unit detects the occurrence of surging in the compressor.

[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.

[0060] 2 Supercharging system 4 Engine 6 Air intake line 8 Exhaust line 10 Supercharger 14 Air bypass line 16 Air bypass valve 18 Wastegate line 20 Wastegate valve 22 Control device 24 Compressor 24a Inlet 26 Turbine 28 Rotating shaft 30 Silencer 31, 37 Flange 32 Impeller 34 Compressor housing 36 Air guide tube 38 Scroll flow path 40 Scroll casing 41 Bolt 42 First side wall 44 Outside air introduction space 46 Second side wall 48 Silencer element 50 Cleaning nozzle 50a Tip portion 50b Base end portion 51 Connector 52 Pressure sensor 53 Tube 54 Through hole 60 Surging detection unit 62 Engine control unit 64 Air bypass valve control unit 66 Wastegate valve control unit 68 Inlet pressure change rate calculation unit 72 Processor 74 RAM 76 ROM 78 HDD 80 Input I / F 82 Output I / F 84 Bus 90 Bolt 91 Nut O Rotation axis P Inlet pressure Th Threshold value a1, a2 Arrows dS / dt Inlet pressure change rate t1 Time

Claims

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

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

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

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

5. A 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. A supercharging system as described in claim 3, further comprising a cleaning nozzle for spraying a cleaning liquid, wherein 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, and the pressure sensor is connected to the cleaning nozzle.

7. A supercharging system as described in claim 1, further comprising an engine control unit for controlling an engine connected to the supercharger, wherein when the surging detection unit detects the occurrence of surging in the compressor, the engine control unit is configured to reduce the load on the engine or stop the engine.

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

9. The supercharging system of claim 1, further comprising: an exhaust line that supplies engine exhaust gas to the turbine; a wastegate line that branches off from the exhaust line upstream of the turbine and connects to the exhaust line downstream of the turbine; a wastegate valve provided in the wastegate line; and a wastegate valve control unit configured to increase the valve opening of the wastegate valve when the surging detection unit detects the occurrence of surging in the compressor.

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