Failure detection device for flow passage switching system

Abstract

To provide a failure detection device for a flow passage switching system that can detect a failure of the flow passage switching system in which, for example, a hole is made in a movable wall, and fluid leaks from the movable wall.SOLUTION: A failure detection device 101 for a flow passage switching system 1 according to an embodiment of the present disclosure is provided. The flow passage switching system 1 comprises a first communication passage 41 for establishing communication between a back pressure chamber 31 and a pump upstream flow passage 71, a second communication passage 42 for establishing communication between the back pressure chamber 31 and a pump downstream flow passage 72, and a pilot valve 51 for switching between communication states of the first communication passage 41 and a second communication passage 42. The first communication passage 41 and the second communication passage 42 comprise a pressure transmission passage 60 formed between the back pressure chamber 31 and the pilot valve 51 as a common passage. At least one of a temperature sensor 111 and a differential pressure sensor 113 is provided in the pressure transmission passage 60. A failure of the flow passage switching system 1 is detected on the basis of a detection value of at least one of the temperature sensor 111 and the differential pressure sensor 113.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a fault detection device for a flow path switching system that switches a flow path of a fluid (for example, cooling water). [Background technology]

[0002] Patent Document 1 discloses a flow path switching system (flow path structure) in which an on-off valve is switched between an open state and a closed state by elastic deformation of a diaphragm disposed between a valve storage chamber and a back pressure chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-82950 A Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 does not disclose anything about detecting a fault in the flow path switching system (for example, an abnormality in which a fluid (heat medium) leaks from a movable wall (diaphragm)).

[0005] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a fault detection device for a flow path switching system that can detect faults in the flow path switching system, such as a hole being formed in the movable wall causing fluid to leak from the movable wall. [Means for solving the problem]

[0006] One aspect of the present disclosure made to solve the above problems includes a flow path switching valve unit and a pump that sends a fluid to the flow path switching valve unit, the flow path switching valve unit including an inlet flow path that introduces the fluid sent by the pump, a first outlet flow path and a second outlet flow path that branch off from the inlet flow path and discharge the fluid, a movable wall chamber, a movable wall disposed within the movable wall chamber, a back pressure chamber partitioned by the movable wall within the movable wall chamber, a drive shaft connected to the movable wall, and a valve body provided on the drive shaft, and by changing the volume of the back pressure chamber to move the movable wall and drive the drive shaft, the first outlet flow path and the second outlet flow path are opened and closed by the valve body to switch the flow paths. the flow path switching system includes a first communication passage that communicates the back pressure chamber with an upstream flow path of the pump, a second communication passage that communicates the back pressure chamber with a downstream flow path of the pump, and a communication state switching valve that switches a communication state between the first communication passage and the second communication passage, the first communication passage and the second communication passage include a pressure transmission passage that is formed as a common passage between the back pressure chamber and the communication state switching valve, at least one of a temperature sensor and a differential pressure sensor is provided in the pressure transmission passage, and a failure of the flow path switching system is detected based on a detection value of at least one of the temperature sensor and the differential pressure sensor.

[0007] According to this aspect, if a failure occurs in the flow path switching system, the failure can be detected based on at least one of the detected values ​​of the temperature and the differential pressure in the pressure transmission passage. Here, if a failure in the flow path switching system occurs such that a hole is formed in the movable wall and fluid leaks from the movable wall, the temperature and the differential pressure in the pressure transmission passage will change compared to when the abnormality does not occur. Therefore, the abnormality can be detected based on at least one of the detected values ​​of the temperature and the differential pressure in the pressure transmission passage.

[0008] In the above aspect, it is preferable to have a fault diagnosis unit that diagnoses whether or not a leakage abnormality has occurred in which the fluid leaks from the movable wall due to communication between the back pressure chamber and the first outlet flow path via the movable wall, based on a detection value of at least one of the temperature sensor and the differential pressure sensor.

[0009] According to this aspect, even if an abnormality occurs in which an extremely small hole is formed in the movable wall causing a minute amount of fluid to leak from the movable wall, this abnormality can be detected based on the detection value of at least one of the temperature sensor and the differential pressure sensor.

[0010] In the above aspect, it is preferable that the failure diagnosis unit diagnoses whether or not the leakage abnormality has occurred based on a change in the detection value of the temperature sensor before and after a switching operation of the communication state switching valve.

[0011] According to this aspect, there is no need to perform dedicated control to diagnose whether or not a leakage abnormality has occurred, and the presence or absence of a leakage abnormality can be diagnosed when performing the switching operation of the communication state switching valve during the normal flow path switching control required by the flow path switching system.

[0012] In the above aspect, it is preferable that the fault diagnosis unit compares the differential pressure in the pressure transmission passage, which is assumed depending on the switching state of the flow path, with the detection value of the differential pressure sensor, to diagnose whether or not the leakage abnormality has occurred.

[0013] According to this aspect, there is no need to perform dedicated control to diagnose whether or not a leakage abnormality has occurred, and the presence or absence of a leakage abnormality can be diagnosed based on the differential pressure in the pressure transmission passage detected while performing the normal flow path switching control required by the flow path switching system.

[0014] In the above aspect, it is preferable that a throttle portion for restricting a passage area is provided at a detection site of the differential pressure sensor in the pressure transmission passage.

[0015] According to this aspect, by narrowing the passage area of ​​the pressure transmission passage with the throttle portion, even a minute differential pressure can be more reliably detected by the differential pressure sensor, thereby improving the accuracy of detecting a leakage anomaly.

[0016] In the above aspect, it is preferable that the fault detection device of the flow path switching system is mounted in a flow path of cooling water for the electric vehicle.

[0017] According to this aspect, if a failure occurs in the flow path switching system, the flow of cooling water for the electric vehicle can be stably controlled by the flow path switching system by detecting the failure and taking measures, thereby improving the energy efficiency of the electric vehicle and contributing to carbon neutrality. Effect of the Invention

[0018] According to the fault detection device for a flow path switching system of the present disclosure, it is possible to detect faults in the flow path switching system, such as a hole occurring in the movable wall causing fluid to leak from the movable wall. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a configuration diagram of a fault detection device for a flow path switching system in the first embodiment, illustrating the state when the flow path switching system is in an upstream flow holding state. [Diagram 2] FIG. 2 is a front view of the flow path switching system. [Diagram 3] FIG. 2 is a perspective view of the flow path switching system. [Figure 4] FIG. 2 is a cross-sectional view (partial external view) of the flow path switching system. [Diagram 5] FIG. 2 is a configuration diagram of a fault detection device for a flow path switching system in the first embodiment, illustrating the state when the flow path switching system is in a switching state to a downstream flow. [Figure 6] FIG. 2 is a configuration diagram of a fault detection device for the flow path switching system in the first embodiment, illustrating the state when the flow path switching system is in a downstream flow holding state. [Figure 7] FIG. 2 is a configuration diagram of a fault detection device for a flow path switching system in the first embodiment, illustrating the state when the flow path switching system is in a switching state to an upstream flow. [Figure 8]FIG. 11 is a diagram showing a case in which a diaphragm leakage anomaly (that is, an anomaly in which a hole is formed in the diaphragm and cooling water leaks from the diaphragm) does not occur when the flow path switching system is in the upstream flow holding state in the first embodiment. [Figure 9] FIG. 11 is a diagram showing an example of a time chart illustrating the ON / OFF state of the pilot valve and the change over time in the detected temperature of the temperature sensor in the first embodiment, and illustrates a case where (temperature T1)≦(temperature T2). [Figure 10] FIG. 11 is a diagram showing an example of a time chart illustrating the ON / OFF state of the pilot valve and the change over time in the detected temperature of the temperature sensor in the first embodiment, and illustrates a case where (temperature T1)≧(temperature T2). [Figure 11] FIG. 11 is a diagram showing a case in which a diaphragm leakage abnormality occurs when the flow path switching system is in an upstream flow holding state in the first embodiment. [Figure 12] FIG. 11 is a diagram showing a case in which no diaphragm leakage abnormality occurs when the flow path switching system is in a downstream flow holding state in the first embodiment. [Figure 13] FIG. 11 is a diagram showing a case in which a diaphragm leakage anomaly occurs when the flow path switching system is in a downstream flow holding state in the first embodiment. [Figure 14] FIG. 11 is a diagram showing a case in which no diaphragm leakage abnormality occurs when the flow path switching system is in a downstream flow holding state in the second embodiment. [Figure 15] FIG. 11 is a diagram showing a case in which a diaphragm leakage anomaly occurs when the flow path switching system is in a downstream flow holding state in the second embodiment. [Figure 16] FIG. 11 is a diagram showing a case in which a diaphragm leakage abnormality does not occur when the flow path switching system is in a switching state to an upstream flow in the second embodiment. [Figure 17] FIG. 11 is a diagram showing an example of a time chart illustrating ON / OFF of a pilot valve and changes over time in the detected temperature of a temperature sensor in the second embodiment. [Figure 18]FIG. 11 is a diagram showing a case in which a diaphragm leakage abnormality occurs when the flow path switching system is in a switching state to an upstream flow in the second embodiment. [Figure 19] FIG. 13 is a diagram showing a case in which no diaphragm leakage abnormality occurs when the flow path switching system is in the upstream flow holding state in the third embodiment. [Figure 20] FIG. 13 is a diagram showing a case in which a diaphragm leakage abnormality occurs when the flow path switching system is in an upstream flow holding state in the third embodiment. [Figure 21] FIG. 13 is a diagram showing a case in which no diaphragm leakage abnormality occurs when the flow path switching system is in a downstream flow holding state in the third embodiment. [Figure 22] FIG. 13 is a diagram showing a case in which a diaphragm leakage anomaly occurs when the flow path switching system is in a downstream flow holding state in the third embodiment. [Figure 23] FIG. [Figure 24] 6 is a diagram showing the relationship between the throttle diameter of a throttle portion and the differential pressure in a pressure transmission passage. FIG.

[0020] An embodiment of a fault detection device for a flow path switching system according to the present disclosure will be described.

[0021] First Embodiment First, the first embodiment will be described.

[0022] The fault detection device 101 (hereinafter simply referred to as "fault detection device 101") of the flow path switching system 1 of this embodiment is, for example, a device mounted in a coolant flow path of an electric vehicle (not shown) and detects a fault in the flow path switching system 1 that controls the flow rate of the coolant. Note that an "electric vehicle" is, for example, a vehicle that is driven by power from a secondary battery as the driving source of the vehicle, such as an electric vehicle or a hybrid vehicle. Also, the coolant is an example of a "fluid" in the present disclosure.

[0023] As shown in FIG. 1, the fault detection device 101 includes a flow path switching system 1, a temperature sensor 111, and a fault diagnosis unit 112.

[0024] (About the flow path switching system) [Stream switching system configuration] 1 to 4, the flow path switching system 1 has a flow path switching valve unit 11, a pump 12, and a control unit 13, and is formed as a single device (i.e., a flow path switching device) in which the flow path switching valve unit 11, the pump 12, and the control unit 13 are integrally formed. Note that the control unit 13 may be provided separately from the flow path switching system 1. For ease of explanation, the control unit 13 is shown only in FIG. 2 and is omitted in the drawings other than FIG. 2.

[0025] The flow path switching valve unit 11 is a valve unit that switches the flow paths. The flow path switching valve unit 11 includes an inlet flow path 21 that introduces the cooling water fed by the pump 12, and a first outlet flow path 22-1 and a second outlet flow path 22-2 that branch off from the inlet flow path 21 and discharge the cooling water.

[0026] The flow path switching valve section 11 also includes a diaphragm chamber 23, a diaphragm 24 arranged in the diaphragm chamber 23, a drive shaft 25 connected to the diaphragm 24, a valve body 26 provided at one end of the drive shaft 25, a first valve seat 27-1, and a second valve seat 27-2.

[0027] The diaphragm chamber 23 includes a back pressure chamber 31 that is partitioned by the diaphragm 24. A spring 32 is provided in the back pressure chamber 31 to bias the diaphragm 24 downward (downward in FIG. 4). In this embodiment, a portion of the diaphragm chamber 23 on the opposite side of the diaphragm 24 from the back pressure chamber 31 is open to the first outlet flow path 22-1. The diaphragm chamber 23 is an example of a "movable wall chamber" in the present disclosure, and the diaphragm 24 is an example of a "movable wall" in the present disclosure.

[0028] The pump 12 is a device that sends cooling water to the flow path switching valve unit 11.

[0029] The control unit 13 is a device that controls the flow path switching system 1. The control unit 13 is a device that has, for example, an arithmetic processing unit such as a CPU, a storage unit such as a ROM that stores a control program and control data processed by the CPU and a RAM that is used as various work areas for control processing, and an input / output interface unit. The control unit 13 performs various controls (for example, control of the pump 12 and a pilot valve 51 described later) and processes of the flow path switching system 1 according to the control program stored in the storage unit.

[0030] In this embodiment, the flow path switching system 1 has a first communication passage 41, a second communication passage 42, and a pilot valve 51, as shown in FIGS.

[0031] The first communication passage 41 is formed by the pressure transmission passage 60 and the first branch passage 61, and is a passage that communicates the back pressure chamber 31 with the pump upstream flow passage 71. The pump upstream flow passage 71 is a flow passage that is provided at a position upstream of the pump 12 in the flow direction of the cooling water, and is an example of the "upstream flow passage of the pump" in the present disclosure.

[0032] The second communication passage 42 is formed by the pressure transmission passage 60 and the second branch passage 62, and is a passage that communicates between the back pressure chamber 31 and the pump downstream flow passage 72. The pump downstream flow passage 72 is a flow passage that is provided at a position downstream of the pump 12 in the flow direction of the cooling water, and is an example of the "pump downstream flow passage" in the present disclosure.

[0033] Further, the first communication passage 41 and the second communication passage 42 are provided with a pressure transmission passage 60 formed between the back pressure chamber 31 and the pilot valve 51 as a common passage.

[0034] The pilot valve 51 is a valve that switches the communication state between the first communication passage 41 and the second communication passage 42. That is, the pilot valve 51 can be switched to either a state in which the pressure transmission passage 60 communicates with the first branch passage 61 or a state in which the pressure transmission passage 60 communicates with the second branch passage 62. The pilot valve 51 is an example of a "communication state switching valve" in the present disclosure.

[0035] [Function of flow path switching system] The flow path switching system 1 configured as above changes the volume of the back pressure chamber 31 to move the diaphragm 24 and drive the drive shaft 25, thereby opening and closing the first outlet flow path 22-1 and the second outlet flow path 22-2 with the valve body 26, thereby switching the flow paths. At this time, the flow path switching system 1 uses the front and rear pressures of the pump 12 to adjust the pressure in the back pressure chamber 31 and operate the diaphragm 24.

[0036] In addition, the pilot valve 51 is switched between a state in which the backpressure chamber 31 communicates with the pump upstream flow path 71 via the first communication passage 41 (i.e., an ON state), and a state in which the backpressure chamber 31 communicates with the pump downstream flow path 72 via the second communication passage 42 (i.e., an OFF state).

[0037] A specific flow path switching will now be described. First, as shown in Fig. 1, the pilot valve 51 is in the OFF state, and the pressure transmission passage 60 and the first branch passage 61 are blocked, while the pressure transmission passage 60 and the second branch passage 62 are connected.

[0038] As a result, the back pressure chamber 31 communicates with the pump downstream side flow path 72 via the second communication passage 42. And, when there is no flow of cooling water in the second communication passage 42, the pressure of the pump downstream side flow path 72 is transmitted to the back pressure chamber 31. Also, the force of the spring 32 acts downward on the diaphragm 24.

[0039] Furthermore, since the valve element 26 is in contact with the second valve seat 27-2 and the valve hole of the first valve seat 27-1 (i.e., a hole provided on the inside of the first valve seat 27-1) is open, a flow path is formed by the inlet flow path 21 and the first outlet flow path 22-1, and the cooling water flows from the inlet flow path 21 to the first outlet flow path 22-1. Then, the pressure of the cooling water flowing from the inlet flow path 21 to the first outlet flow path 22-1 acts on the valve element 26 downward (i.e., in the direction of the second valve seat 27-2). In this way, the flow path switching system 1 is in an upstream flow holding state (i.e., a state in which the upstream flow (flow to the first outlet flow path 22-1) is held).

[0040] 1 and 5 to 7, the arrows indicate the forces acting, and pressure P0 is the pressure in the pump upstream flow path 71, pressure P1 is the pressure in the first outlet flow path 22-1, and pressure P2 is the pressure in the second outlet flow path 22-2. Furthermore, pressure P3 is the pressure in the pump downstream flow path 72 (inlet flow path 21), and pressure Pa is the pressure in the back pressure chamber 31.

[0041] Next, as shown in FIG. 5, when the pilot valve 51 is switched to the ON state, the pressure transmission passage 60 and the first branch passage 61 are communicated with each other, while the pressure transmission passage 60 and the second branch passage 62 are blocked from each other.

[0042] As a result, the back pressure chamber 31 communicates with the pump upstream flow path 71 through the first communication passage 41. At this time, the pressure Pa of the back pressure chamber 31 is higher than the pressure P0 of the pump upstream flow path 71. Therefore, the cooling water in the back pressure chamber 31 is discharged to the pump upstream flow path 71 through the first communication passage 41, so that the pressure Pa of the back pressure chamber 31 decreases and an upward force acts on the diaphragm 24.

[0043] Then, the volume of the back pressure chamber 31 decreases, the diaphragm 24 moves upward, and the drive shaft 25 moves upward, so that the valve body 26 moves away from the second valve seat 27-2. In this way, the flow path switching system 1 is in a switching state to the downstream flow (i.e., a switching state from the upstream flow to the downstream flow).

[0044] Next, as shown in FIG. 6, when the pilot valve 51 is maintained in the ON state, the valve body 26 abuts against the first valve seat 27-1. As a result, the valve hole of the second valve seat 27-2 (i.e., a hole provided on the inside of the second valve seat 27-2) is opened, so that a flow path is formed by the inlet flow path 21 and the second outlet flow path 22-2, and the cooling water flows from the inlet flow path 21 to the second outlet flow path 22-2. Then, the pressure of the cooling water flowing from the inlet flow path 21 to the second outlet flow path 22-2 acts on the valve body 26 upward (i.e., in the direction of the first valve seat 27-1). In this way, the flow path switching system 1 is in a downstream flow holding state (i.e., a state in which the downstream flow (flow to the second outlet flow path 22-2) is held). At this time, the operation of the diaphragm 24 and the drive shaft 25 is stopped.

[0045] Next, as shown in FIG. 7, when the pilot valve 51 is switched to the OFF state, the pressure transmission passage 60 and the first branch passage 61 are blocked, while the pressure transmission passage 60 and the second branch passage 62 are communicated.

[0046] As a result, the back pressure chamber 31 communicates with the pump downstream flow path 72 through the second communication passage 42. At this time, the pressure Pa of the back pressure chamber 31 is lower than the pressure P3 of the pump downstream flow path 72. Therefore, the cooling water in the pump downstream flow path 72 flows into the back pressure chamber 31 through the second communication passage 42, so that the pressure Pa of the back pressure chamber 31 increases and a downward force acts on the diaphragm 24.

[0047] Then, the volume of the back pressure chamber 31 increases, the diaphragm 24 moves downward, and the drive shaft 25 moves downward, so that the valve body 26 moves away from the first valve seat 27-1. In this way, the flow path switching system 1 enters an upstream flow switching state (i.e., a state in which the flow path switching system 1 switches from downstream flow to upstream flow).

[0048] Thereafter, when the pilot valve 51 is maintained in the OFF state, the flow path switching system 1 again goes into the upstream flow holding state as shown in FIG.

[0049] (Temperature sensor and fault diagnosis section) As shown in FIG. 1, the temperature sensor 111 is provided in the pressure transmission passage 60 and detects the temperature of the cooling water in the pressure transmission passage 60 .

[0050] The fault diagnosis unit 112 includes, for example, an arithmetic processing unit such as a CPU, a storage unit such as a ROM or a RAM, and an input / output interface unit. The fault diagnosis unit 112 is connected to the temperature sensor 111 via the input / output interface unit, and can receive information on the detected temperature TS, which is the detected value, from the temperature sensor 111.

[0051] The fault diagnosis unit 112 detects a fault in the flow path switching system 1 based on the detected temperature TS of the temperature sensor 111. Specifically, the fault diagnosis unit 112 diagnoses, as a fault in the flow path switching system 1, whether or not an abnormality has occurred in which cooling water leaks from the diaphragm 24 (hereinafter referred to as a "diaphragm leakage abnormality") due to, for example, a hole HO being formed in the diaphragm 24 and the back pressure chamber 31 and the first outlet flow path 22-1 communicating with each other via the diaphragm 24.

[0052] (Method of detecting diaphragm leakage abnormalities using a fault detection device) Next, a description will be given of a method for detecting a diaphragm leakage abnormality by the failure detection device 101. Note that a diaphragm leakage abnormality is an example of a "leak abnormality" in the present disclosure.

[0053] For example, as shown in FIG. 8, in the upstream flow holding state, when no diaphragm leakage abnormality occurs (that is, during normal operation), the flow of cooling water in the pressure transmission passage 60 stops.

[0054] 9 and 10, when the pilot valve 51 is OFF, there is a temperature difference ΔT (i.e., a temperature difference of a predetermined temperature or more) between the temperature TS detected by the temperature sensor 111 and the temperature T1 of the first outlet flow path 22-1 (i.e., the temperature of the cooling water in the first outlet flow path 22-1, the temperature shown by the thin solid line in FIG. 9 and 10). In addition, there is a temperature difference ΔT between the temperature TS detected by the temperature sensor 111 and the temperature T2 of the pump downstream flow path 72 (i.e., the temperature of the cooling water in the pump downstream flow path 72, the temperature shown by the thin dashed line in FIG. 9 and 10).

[0055] That is, the detected temperature TS of the temperature sensor 111 does not follow the temperature T1 of the first outlet flow path 22-1 or the temperature T2 of the pump downstream flow path 72. Note that Fig. 9 shows the case where (temperature T1) ≦ (temperature T2), and Fig. 10 shows the case where (temperature T1) ≧ (temperature T2).

[0056] Therefore, in this embodiment, when the upstream flow is maintained, if a temperature difference ΔT occurs between the detected temperature TS of the temperature sensor 111 and the temperature T1 of the first outlet flow path 22-1 or between the temperature T2 of the pump downstream flow path 72, the fault diagnosis unit 112 diaphragm leakage abnormality is not detected.

[0057] Incidentally, immediately after the pilot valve 51 is switched from ON to OFF, even if no diaphragm leakage abnormality occurs, the flow of cooling water stops when the change in the volume of the backpressure chamber 31 stops after the cooling water flows from the pump downstream side flow path 72 via the second communication passage 42 (including the pressure transmission passage 60) to the backpressure chamber 31. Therefore, as shown by the thick solid lines in Figures 9 and 10, the detected temperature TS of the temperature sensor 111 fluctuates immediately after the pilot valve 51 is switched from ON to OFF (time γ in the figures).

[0058] 11, when a diaphragm leakage abnormality occurs in the upstream flow holding state (i.e., during an abnormality), the cooling water leaks from the back pressure chamber 31 to the first outlet flow path 22-1 through the hole HO of the diaphragm 24. Therefore, in the pressure transmission passage 60, the flow of the cooling water continues from the pump downstream side flow path 72 side toward the back pressure chamber 31 side.

[0059] 9 and 10 (i.e., the line labeled "abnormal"), when the pilot valve 51 is OFF (more specifically, at time α in FIGS. 9 and 10), the temperature TS detected by the temperature sensor 111 becomes equal to the temperature T2 of the pump downstream flow path 72. In other words, the temperature TS detected by the temperature sensor 111 follows the temperature T2 of the pump downstream flow path 72.

[0060] At this time, the pump downstream flow path 72 and the first outlet flow path 22-1 communicate with each other via the introduction flow path 21, and the temperature T2 of the pump downstream flow path 72 and the temperature T1 of the first outlet flow path 22-1 are equal, so that the detected temperature TS of the temperature sensor 111 is also equal to the temperature T1 of the first outlet flow path 22-1. That is, the detected temperature TS of the temperature sensor 111 also follows the temperature T1 of the first outlet flow path 22-1.

[0061] Therefore, in this embodiment, when the upstream flow is maintained in the upstream flow holding state, the fault diagnosis unit 112 diagnoses that a diaphragm leakage abnormality has occurred when the detected temperature TS of the temperature sensor 111 becomes equal (or approximately equal) to the temperature T2 of the pump downstream flow path 72 (and the temperature T1 of the first outlet flow path 22-1).

[0062] 12, for example, in the downstream flow holding state, when no diaphragm leakage abnormality occurs, the flow of cooling water stops in the pressure transmission passage 60. Therefore, as shown by the thick solid lines in Fig. 9 and 10, when the pilot valve 51 is ON, a temperature difference ΔT occurs between the temperature TS detected by the temperature sensor 111 and the temperature T1 of the first outlet flow passage 22-1 or the temperature T2 of the pump downstream flow passage 72. In other words, the temperature TS detected by the temperature sensor 111 does not follow the temperature T1 of the first outlet flow passage 22-1 or the temperature T2 of the pump downstream flow passage 72.

[0063] Therefore, in this embodiment, when a temperature difference ΔT occurs between the detected temperature TS of the temperature sensor 111 and the temperature T1 of the first outlet flow path 22-1 or between the detected temperature TS of the temperature sensor 111 and the temperature T2 of the pump downstream flow path 72 in the downstream flow path holding state, the fault diagnosis unit 112 diaphragm leakage abnormality is diagnosed as not occurring.

[0064] On the other hand, for example, as shown in Fig. 13, in the downstream flow holding state, when a diaphragm leakage abnormality occurs, cooling water leaks from the first outlet flow passage 22-1 to the back pressure chamber 31 through the hole HO of the diaphragm 24. Therefore, in the pressure transmission passage 60, the flow of cooling water continues from the back pressure chamber 31 side toward the pump downstream side flow passage 72 side (more specifically, the pump upstream side flow passage 71 side). Therefore, as shown by the thick dashed line in Fig. 9 and Fig. 10, when the pilot valve 51 is ON, the detected temperature TS of the temperature sensor 111 becomes equal to the temperature T1 of the pump downstream side flow passage 72. That is, the detected temperature TS of the temperature sensor 111 follows the temperature T1 of the first outlet flow passage 22-1.

[0065] Therefore, in this embodiment, when the detection temperature TS of the temperature sensor 111 becomes equal (or approximately equal) to the temperature T1 of the first outlet flow path 22-1 in the downstream flow holding state, the fault diagnosis unit 112 diagnoses that a diaphragm leakage abnormality has occurred.

[0066] 13, the direction of the cooling water flow in the pressure transmission passage 60 changes from the upstream flow holding state shown in Fig. 11 to the downstream flow holding state shown in Fig. 13, and the cooling water flow changes from the flow from the pump downstream flow path 72 side to the back pressure chamber 31 side to the flow from the back pressure chamber 31 side to the pump downstream flow path 72 side (more specifically, the pump upstream flow path 71 side). Therefore, the detected temperature TS of the temperature sensor 111 changes.

[0067] Specifically, when the temperature T1 of the first outlet flow path 22-1 is low and the temperature T2 of the pump downstream flow path 72 is high (i.e., (temperature T1)<(temperature T2)), the detected temperature TS of the temperature sensor 111 changes from high to low. On the other hand, when the temperature T1 of the first outlet flow path 22-1 is high and the temperature T2 of the pump downstream flow path 72 is low (i.e., (temperature T1)>(temperature T2)), the detected temperature TS of the temperature sensor 111 changes from low to high.

[0068] Therefore, in this embodiment, when the pilot valve 51 switches from the upstream flow holding state to the downstream flow holding state due to a switching operation (i.e., switching operation from OFF to ON) the fault diagnosis unit 112 diagnoses that a diaphragm leakage abnormality has occurred if the detected temperature TS of the temperature sensor 111 changes (see time β in Figures 9 and 10, i.e., changes by more than a predetermined temperature).

[0069] On the other hand, if the detected temperature TS of the temperature sensor 111 does not change when the pilot valve 51 switches from the upstream flow hold state to the downstream flow hold state due to the switching operation, the fault diagnosis unit 112 diaphragm leakage abnormality is not generated.

[0070] In this manner, in this embodiment, the failure diagnosis unit 112 diagnoses whether or not a diaphragm leakage abnormality has occurred based on the change in the detected temperature TS of the temperature sensor 111 before and after the switching operation of the pilot valve 51.

[0071] (Effects of this embodiment) According to this embodiment, the temperature sensor 111 is provided in the pressure transmission passage 60, and a failure in the flow path switching system 1 is detected based on the detected temperature TS of the temperature sensor 111.

[0072] As a result, when a failure occurs in the flow path switching system 1, the failure can be detected based on the detected temperature TS of the temperature sensor 111. Here, when a diaphragm leakage abnormality occurs as a failure in the flow path switching system 1, a change occurs in the temperature of the pressure transmission passage 60 compared to when a diaphragm leakage abnormality does not occur. Therefore, the diaphragm leakage abnormality can be detected based on the detected temperature TS of the temperature sensor 111.

[0073] In this embodiment, the failure diagnosis unit 112 diagnoses whether or not a diaphragm leakage abnormality has occurred based on the detected temperature TS of the temperature sensor 111.

[0074] As a result, even if an extremely small hole is formed in the diaphragm 24 and a diaphragm leakage abnormality occurs such that a minute amount of cooling leaks from the diaphragm 24, the diaphragm leakage abnormality can be detected based on the detected temperature TS of the temperature sensor 111.

[0075] Furthermore, the passage area of ​​the pressure transmission passage 60 is small and is almost constant along the length of the pressure transmission passage 60. Therefore, no matter where the temperature sensor 111 is provided in the pressure transmission passage 60, the detected temperature TS of the temperature sensor 111 can be detected stably. Even if the temperature of the pressure transmission passage 60 changes slightly, this slight temperature change can be detected by the temperature sensor 111. Therefore, the fault diagnosis unit 112 can stably diagnose the presence or absence of a diaphragm leakage abnormality based on the detected temperature TS of the temperature sensor 111. Note that the passage area of ​​the pressure transmission passage 60 refers to the cross-sectional area of ​​the pressure transmission passage 60 when viewed from the flow direction of the cooling water.

[0076] Furthermore, the failure diagnosis unit 112 diagnoses whether or not a diaphragm leakage abnormality has occurred based on the change in the detection value of the temperature sensor 111 before and after the switching operation of the pilot valve 51 .

[0077] This eliminates the need for dedicated control to diagnose whether or not a diaphragm leakage abnormality has occurred, and enables diagnosis of whether or not a diaphragm leakage abnormality has occurred when the pilot valve 51 is switched during normal flow path switching control required by the flow path switching system 1. Therefore, if a diaphragm leakage abnormality occurs, it is possible to immediately detect the occurrence of the diaphragm leakage abnormality and take action.

[0078] Moreover, the fault detection device 101 is mounted in a flow path of cooling water of the electric vehicle.

[0079] Therefore, if a failure occurs in the flow path switching system 1, it can be detected and dealt with, thereby stably controlling the flow of cooling water for the electric vehicle by the flow path switching system 1. This can improve the energy efficiency of the electric vehicle and contribute to carbon neutrality.

[0080] <Second embodiment> Next, the second embodiment will be described. The differences from the first embodiment will be described, and a description of the points in common with the first embodiment will be omitted.

[0081] In this embodiment, it is assumed that the ambient temperature of the temperature sensor 111 is lower than the temperature T2 of the pump downstream flow path 72 (for example, the ambient temperature of the temperature sensor 111 is the outside air temperature, and the temperature T2 of the pump downstream flow path 72 is higher than the outside air temperature).

[0082] 14, in the downstream flow holding state, when no diaphragm leakage abnormality occurs, the flow of cooling water stops in the pressure transmission passage 60. Here, the ambient temperature of the temperature sensor 111 is lower than the temperature T2 of the pump downstream flow passage 72. Therefore, when the pilot valve 51 is ON, the detected temperature TS of the temperature sensor 111 is lower than the temperature T2 of the pump downstream flow passage 72.

[0083] Therefore, in this embodiment, when the downstream flow is held, if the detected temperature TS of the temperature sensor 111 is lower than the temperature T2 of the pump downstream flow path 72 (e.g., lower by a predetermined temperature or more), the fault diagnosis unit 112 diaphragm leakage abnormality is diagnosed as not occurring.

[0084] On the other hand, for example, as shown in Fig. 15, in the downstream flow holding state, when a diaphragm leakage abnormality occurs, cooling water leaks from the first outlet flow passage 22-1 to the back pressure chamber 31 through the hole HO of the diaphragm 24. Therefore, in the pressure transmission passage 60, the flow of cooling water continues from the back pressure chamber 31 side toward the pump downstream side flow passage 72 side (more specifically, the pump upstream side flow passage 71 side). Therefore, when the pilot valve 51 is ON, the detected temperature TS of the temperature sensor 111 becomes equal to the temperature T1 of the first outlet flow passage 22-1. That is, the detected temperature TS of the temperature sensor 111 follows the temperature T1 of the first outlet flow passage 22-1.

[0085] Therefore, in this embodiment, when the detection temperature TS of the temperature sensor 111 becomes equal (or approximately equal) to the temperature T1 of the first outlet flow path 22-1 in the downstream flow holding state, the fault diagnosis unit 112 diagnoses that a diaphragm leakage abnormality has occurred.

[0086] 16, in the state switched to the upstream flow, if no diaphragm leakage abnormality occurs, the cooling water (at temperature T2) flows from the pump downstream flow path 72 to the back pressure chamber 31 in the pressure transmission passage 60, and the detected temperature TS of the temperature sensor 111 rises once. Then, when the change in the volume of the back pressure chamber 31 thereafter stops and the flow of the cooling water stops, the ambient temperature of the temperature sensor 111 is lower than the temperature T2 of the pump downstream flow path 72, so the detected temperature TS of the temperature sensor 111 drops.

[0087] 17, when the pilot valve 51 is switched from ON to OFF, the detected temperature TS of the temperature sensor 111 rises once and then falls. Then, the detected temperature TS of the temperature sensor 111 becomes lower than the temperature T2 of the pump downstream flow path 72.

[0088] Therefore, in this embodiment, when the flow is switched to the upstream flow state, if the detected temperature TS of the temperature sensor 111 rises once and then drops to become lower than the temperature T2 of the pump downstream flow path 72, the fault diagnosis unit 112 diaphragm leakage abnormality is diagnosed as not occurring.

[0089] 18, when a diaphragm leakage abnormality occurs in the state switched to the upstream flow, the flow of cooling water continues from the pump downstream flow path 72 to the back pressure chamber 31 in the pressure transmission passage 60. Therefore, when the pilot valve 51 switches from ON to OFF, the detected temperature TS of the temperature sensor 111 does not decrease. That is, the detected temperature TS of the temperature sensor 111 follows the temperature T2 of the pump downstream flow path 72.

[0090] In detail, if (temperature T1)<(temperature T2) in the downstream flow holding state, when the pilot valve 51 is switched from ON to OFF, the detected temperature TS of the temperature sensor 111 rises once and then becomes temperature T2 (=temperature T1) without decreasing (see the thin dashed line in Figure 15).

[0091] Furthermore, if (temperature T1) = (temperature T2) in the downstream flow holding state, when the pilot valve 51 is switched from ON to OFF, the detected temperature TS of the temperature sensor 111 remains at temperature T2 (= temperature T1) without rising or falling (see the thin solid line in Figure 15).

[0092] Furthermore, if (temperature T1)>(temperature T2) in the downstream flow holding state, when the pilot valve 51 is switched from ON to OFF, the detected temperature TS of the temperature sensor 111 drops once and then does not drop further, becoming temperature T2 (=temperature T1) (see the thin dotted line in Figure 15).

[0093] Therefore, in this embodiment, when the flow is switched to the upstream flow state, if the detected temperature TS of the temperature sensor 111 eventually becomes equal (or almost equal) to the temperature T2 of the pump downstream flow path 72, even if the detected temperature TS changes once, the fault diagnosis unit 112 diaphragm leakage anomaly is diagnosed as occurring.

[0094] <Third embodiment> Next, a third embodiment will be described. Differences from the first and second embodiments will be described, and descriptions of commonalities with the first and second embodiments will be omitted.

[0095] In this embodiment, instead of the temperature sensor 111, a differential pressure sensor 113 is provided in the pressure transmission passage 60 to detect a differential pressure between two positions in the pressure transmission passage 60.

[0096] In this embodiment, the fault diagnosis unit 112 detects a fault in the flow path switching system 1 based on the detected differential pressure PS, which is the detection value of the differential pressure sensor 113. Specifically, the fault diagnosis unit 112 compares the differential pressure ΔP in the pressure transmission passage 60 assumed according to the switching state of the flow paths (i.e., the differential pressure between two positions in the pressure transmission passage 60) with the detected differential pressure PS of the differential pressure sensor 113, and diagnoses the presence or absence of a diaphragm leakage abnormality as a fault in the flow path switching system 1.

[0097] In this embodiment, as shown in FIG. 23, a restriction 114 for restricting the passage area is provided at the detection site of the differential pressure sensor 113 in the pressure transmission passage 60.

[0098] 19, in the upstream flow holding state, when no diaphragm leakage abnormality occurs, the flow of cooling water stops in the pressure transmission passage 60. Therefore, no pressure difference occurs in the pressure transmission passage 60.

[0099] Therefore, in this embodiment, when the upstream flow is held and the detected differential pressure PS of the temperature sensor 111 is 0, i.e., when no differential pressure is generated in the pressure transmission passage 60, the fault diagnosis unit 112 diaphragm leakage abnormality is not generated.

[0100] 20, when the diaphragm leakage abnormality occurs in the upstream flow holding state, the flow of cooling water continues from the pump downstream flow path 72 side to the back pressure chamber 31 side in the pressure transmission passage 60. Therefore, a pressure difference occurs in the pressure transmission passage 60.

[0101] Therefore, in this embodiment, when the detected differential pressure PS of the differential pressure sensor 113 is equal to or greater than a predetermined pressure, i.e., when a differential pressure occurs in the pressure transmission passage 60, the fault diagnosis unit 112 diagnoses that a diaphragm leakage abnormality has occurred.

[0102] 21, when no diaphragm leakage abnormality occurs in the downstream flow holding state, the flow of cooling water stops in the pressure transmission passage 60. Therefore, no pressure difference occurs in the pressure transmission passage 60.

[0103] Therefore, in this embodiment, when the detected differential pressure PS of the temperature sensor 111 is 0 in the downstream flow holding state, that is, when no differential pressure is generated in the pressure transmission passage 60, the fault diagnosis unit 112 diaphragm leakage abnormality is diagnosed as not occurring.

[0104] 22, when a diaphragm leakage abnormality occurs in the downstream flow holding state, the flow of cooling water continues from the back pressure chamber 31 side to the pump downstream flow path 72 side (more specifically, the pump upstream flow path 71 side) in the pressure transmission passage 60. Therefore, a pressure difference occurs in the pressure transmission passage 60.

[0105] Therefore, in this embodiment, when the detected differential pressure PS of the differential pressure sensor 113 is equal to or greater than a predetermined pressure, i.e., when a differential pressure occurs in the pressure transmission passage 60, the fault diagnosis unit 112 diagnoses that a diaphragm leakage abnormality has occurred.

[0106] According to this embodiment, the fault diagnosis unit 112 compares the differential pressure ΔP in the pressure transmission passage 60, which is assumed depending on the switching state of the flow path, with the differential pressure PS detected by the differential pressure sensor 113, to diagnose whether or not a diaphragm leakage abnormality has occurred.

[0107] As a result, there is no need to perform dedicated control to diagnose whether or not a diaphragm leakage abnormality has occurred, and the presence or absence of a diaphragm leakage abnormality can be diagnosed based on the differential pressure ΔP in the pressure transmission passage 60 detected while performing the normal flow path switching control required by the flow path switching system 1.

[0108] Furthermore, the passage area of ​​the pressure transmission passage 60 is small and is approximately constant along the length of the pressure transmission passage 60. Therefore, no matter where the differential pressure sensor 113 is provided in the pressure transmission passage 60, the detected differential pressure PS of the differential pressure sensor 113 can be stably detected. Furthermore, even if the differential pressure ΔP in the pressure transmission passage 60 changes slightly, this slight change in the differential pressure can be detected by the differential pressure sensor 113. Therefore, the failure diagnosis unit 112 can stably diagnose the presence or absence of a diaphragm leakage abnormality based on the detected differential pressure PS of the differential pressure sensor 113.

[0109] Further, a restriction 114 for restricting the passage area is provided at a detection site of the differential pressure sensor 113 in the pressure transmission passage 60 .

[0110] In this way, by narrowing the passage area of ​​the pressure transmission passage 60 by the restrictor 114, the pressure difference can be reliably detected by the differential pressure sensor 113 even when a minute pressure difference occurs in the pressure transmission passage 60. Therefore, the accuracy of detecting a diaphragm leakage abnormality can be improved.

[0111] 24, the smaller the throttling diameter DA (see FIG. 23) of the throttling portion 114 is made, the larger the differential pressure ΔP in the pressure transmission passage 60 becomes, and therefore the change in the detected differential pressure PS of the differential pressure sensor 113 becomes more likely to appear depending on the presence or absence of the diaphragm leakage anomaly. Therefore, the smaller the throttling diameter DA of the throttling portion 114 is made, the more accurate the detection of the presence or absence of the diaphragm leakage anomaly based on the detected differential pressure PS of the differential pressure sensor 113 becomes.

[0112] It should be noted that the above-described embodiments are merely examples and do not limit the present disclosure in any way. Needless to say, various improvements and modifications are possible without departing from the spirit and scope of the present disclosure.

[0113] For example, both the temperature sensor 111 and the differential pressure sensor 113 may be provided in the pressure transmission passage 60. In this case, the fault diagnosis unit 112 may detect a fault in the flow path switching system 1 based on the detection values ​​of both the temperature sensor 111 and the differential pressure sensor 113.

[0114] Furthermore, the fault detection device 101 can also detect faults in the flow path switching system other than diaphragm leakage abnormality, based on the detected value of at least one of the temperature sensor 111 and the differential pressure sensor 113.

[0115] In addition, the above description has given an example of the flow path switching system 1 as a single device (flow path switching device) in which the flow path switching valve unit 11 and the pump 12 are integrally formed, but other examples include systems in which the flow path switching valve unit 11 and the pump 12 are formed separately. [Explanation of symbols]

[0116] 1. Flow path switching system 11 Flow path switching valve 12 Pump 21 Inlet channel 22-1 First outlet flow path 22-2 Second outlet flow path 23 Diaphragm chamber 24 Diaphragm 25 Drive shaft 26 Valve body 31 Back pressure chamber 41 1st communication passage 42 2nd communication passage 51 Pilot valve 60 Pressure transmission passage 71 Pump upstream flow passage 72 Pump downstream flow path 101 (Flow path switching system) fault detection device 111 Temperature Sensor 112 Fault diagnosis section 113 Differential Pressure Sensor 114 Squeezing section TS (Temperature sensor) Detected temperature T1 (First outlet passage) temperature T2 (Pump downstream flow path) temperature PS (Differential pressure sensor) Detected differential pressure

Claims

1. A flow path switching valve unit; a pump for supplying a fluid to the flow path switching valve unit, the flow path switching valve unit includes an inlet flow path for introducing the fluid pumped by the pump, a first outlet flow path and a second outlet flow path branching from the inlet flow path for discharging the fluid, a movable wall chamber, a movable wall disposed within the movable wall chamber, a back pressure chamber partitioned by the movable wall within the movable wall chamber, a drive shaft connected to the movable wall, and a valve body provided on the drive shaft, a flow passage switching system that switches flow passages by opening and closing the first outlet flow passage and the second outlet flow passage using the valve body by changing a volume of the back pressure chamber to move the movable wall and drive the drive shaft, The flow path switching system includes: a first communication passage that communicates the back pressure chamber with an upstream flow passage of the pump; a second communication passage that communicates the back pressure chamber with a downstream flow passage of the pump; a communication state switching valve that switches a communication state between the first communication passage and the second communication passage, the first communication passage and the second communication passage include a pressure transmission passage formed as a common passage between the back pressure chamber and the communication state switching valve, At least one of a temperature sensor and a differential pressure sensor is provided in the pressure transmission passage, detecting a failure in the flow path switching system based on a detection value of at least one of the temperature sensor and the differential pressure sensor; A fault detection device for a flow path switching system comprising:

2. In the fault detection device for a flow path switching system according to claim 1, a fault diagnosis unit that diagnoses whether or not a leakage abnormality has occurred in which the fluid leaks from the movable wall due to communication between the back pressure chamber and the first outlet flow path via the movable wall, based on a detection value of at least one of the temperature sensor and the differential pressure sensor; A fault detection device for a flow path switching system comprising:

3. In the fault detection device for a flow path switching system according to claim 2, the fault diagnosis unit diagnoses whether or not the leakage abnormality has occurred based on a change in the detection value of the temperature sensor before and after a switching operation of the communication state switching valve; A fault detection device for a flow path switching system comprising:

4. In the fault detection device for a flow path switching system according to claim 2, the fault diagnosis unit compares a differential pressure in the pressure transmission passage estimated according to a switching state of the flow passage with a detection value of the differential pressure sensor to diagnose whether or not the leakage abnormality has occurred; A fault detection device for a flow path switching system comprising:

5. 5. The fault detection device for a flow path switching system according to claim 1, a restrictor portion for restricting a passage area is provided at a detection portion of the differential pressure sensor in the pressure transmission passage; A fault detection device for a flow path switching system comprising:

6. 5. The fault detection device for a flow path switching system according to claim 1, The fault detection device of the flow path switching system is mounted in a flow path of cooling water of an electric vehicle; A fault detection device for a flow path switching system comprising:

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