Thermal Management Systems for Vehicles

Abstract

To detect a slightly opened state of a selector valve for controlling flows of a plurality of flow passages.SOLUTION: A heat management system includes a selector valve which switches a first mode in which a first flow passage is separated from a second flow passage and a second mode in which the first and second flow passages are partially connected so as to form a third flow passage. A temperature of a heat medium in the second flow passage is higher than a temperature of a heat medium in the first flow passage. In the first mode, a control section acquires measured values of a first temperature of the first flow passage and a second temperature of the second flow passage at a first prescribed time when prescribed time passes from a point of time when at least one of the first temperature and the second temperature starts to rise. The control section acquires estimated values of the first and second temperatures at the first prescribed time when the selector valve is not in a slightly opened state. The control section determines that the selector valve is in the slightly opened state when the measured value of the first temperature exceeds a prescribed threshold to be larger than the estimated value of the first temperature and the measured value of the second temperature falls below the prescribed threshold to be smaller than the estimated value of the second temperature.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] TECHNICAL FIELD The technology disclosed herein relates to thermal management systems for vehicles. [Background technology]

[0002] Patent Document 1 discloses a vehicle thermal management system capable of switching the connection state of a plurality of flow paths. To switch the flow paths, the system is provided with a switching valve that controls the flow of the plurality of flow paths. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-30289 A Summary of the Invention [Problem to be solved by the invention]

[0004] When controlling the flow of multiple flow paths, it is important to detect abnormalities in the switching valve. When the switching valve breaks down and stops operating, the temperature behavior of the heat transfer medium is clearly abnormal, making detection easy. However, there are cases where the valve body stops halfway, causing the heat transfer medium to leak from a gap, resulting in a slightly open state. This slightly open state is more difficult to detect than a breakdown. This specification provides technology that can solve such problems. [Means for solving the problem]

[0005] The thermal management system disclosed in the present specification is used in a vehicle. The thermal management system includes a first flow path through which a heat medium flows, a first pump arranged on the first flow path and circulating the heat medium in the first flow path, and a first temperature sensor arranged on the first flow path and capable of measuring a first temperature of the heat medium. The thermal management system includes a second flow path through which a heat medium flows, a second pump arranged on the second flow path and circulating the heat medium in the second flow path, and a second temperature sensor arranged on the second flow path and capable of measuring a second temperature of the heat medium. The thermal management system includes a switching valve configured to be switchable between a first mode in which the first flow path and the second flow path are separated, and a second mode in which a third flow path is formed by a part of the first flow path and a part of the second flow path being connected. The thermal management system includes a control unit that determines whether the switching valve is in a slightly open state. The temperature of the heat medium in the second flow path is higher than the temperature of the heat medium in the first flow path. In the first mode, the control unit acquires a measurement value of the first temperature from the first temperature sensor and acquires a measurement value of the second temperature from the second temperature sensor at a first predetermined time when a predetermined time has elapsed since at least one of the first temperature and the second temperature started to rise. The control unit acquires an estimate value of the first temperature and an estimate value of the second temperature at the first predetermined time when the switching valve is not in a slightly open state. The control unit determines that the switching valve is in a slightly open state when the measurement value of the first temperature is larger than the estimate value of the first temperature by more than a predetermined threshold and the measurement value of the second temperature is smaller than the estimate value of the second temperature by more than a predetermined threshold.

[0006] When the switching valve is slightly open in the first mode, the heat medium is slightly mixed between the first flow path and the second flow path. Therefore, heat is transferred from the high-temperature heat medium in the second flow path to the low-temperature heat medium in the first flow path. Due to this heat transfer, the temperature of the heat medium in the first flow path becomes higher than the temperature estimated when the switching valve is not in the slightly open state. Also, the temperature of the heat medium in the second flow path becomes lower than the temperature estimated when the switching valve is not in the slightly open state. Therefore, it is possible to detect that the switching valve is in the slightly open state by detecting that the measured value of the first temperature is larger than the estimated value of the first temperature by more than a predetermined threshold and that the measured value of the second temperature is smaller than the estimated value of the second temperature by more than a predetermined threshold. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 illustrates a thermal management system 100. [Diagram 2] FIG. 1 illustrates a thermal management system 100. [Diagram 3] 4 is a temperature graph of the heat transfer medium in the first mode. [Figure 4] 1 is an example of a temperature graph during a fault. [Diagram 5] 4 is a temperature graph of the heat transfer medium in the first mode. [Figure 6] 4 is a temperature graph of the heat transfer medium in the second mode. [Figure 7] FIG. 11 is a flow diagram illustrating a process for correcting a slightly open state. [Figure 8] 4 is a calculation example of a first pressure P1 and a second pressure P2. [Figure 9] FIG. 10 is a diagram showing a modified low-temperature radiator circuit 10a. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] In one embodiment of the present technology, the thermal management system may further include a third temperature sensor arranged on the third flow path and capable of measuring a third temperature of the heat medium. The first temperature sensor may be arranged on the first flow path that does not form the third flow path. The second temperature sensor may be arranged on the second flow path that does not form the third flow path. The temperature of the heat medium in the third flow path may be higher than the temperatures of the heat medium in the first flow path and the second flow path. In the second mode, the control unit may acquire a measurement value of the first temperature from the first temperature sensor, acquire a measurement value of the second temperature from the second temperature sensor, and acquire a measurement value of the third temperature from the third temperature sensor at a second predetermined time when a predetermined time has elapsed from the time when the third temperature starts to increase. The control unit may acquire an estimated value of the first temperature, an estimated value of the second temperature, and an estimated value of the third temperature at the second predetermined time when the switching valve is not in a slightly open state. The control unit may determine that the switching valve is in a slightly open state when the measured value of the first temperature is greater than the estimated value of the first temperature by more than a predetermined threshold, the measured value of the second temperature is greater than the estimated value of the second temperature by more than a predetermined threshold, and the measured value of the third temperature is smaller than the estimated value of the third temperature by more than a predetermined threshold.

[0009] When the switching valve is in the slightly open state in the second mode, the heat medium is slightly mixed between the first and second flow paths, which do not form the third flow path, and the third flow path. Therefore, heat is transferred from the high-temperature heat medium in the third flow path to the low-temperature heat medium in the first and second flow paths. Due to this heat transfer, the temperature of the heat medium in the third flow path becomes lower than the temperature estimated when the switching valve is not in the slightly open state. Also, the temperatures of the heat medium in the first and second flow paths become higher than the temperature estimated when the switching valve is not in the slightly open state. Therefore, it is possible to detect that the switching valve is in the slightly open state by detecting that the measured value of the third temperature is smaller than the estimated value of the third temperature by more than a predetermined threshold value, and that the measured values ​​of the first and second temperatures are larger than the estimated values ​​of the first and second temperatures by more than a predetermined threshold value.

[0010] In one embodiment of the present technology, the thermal management system may include a heat generation map indicating the amount of heat generated by a heat source in each of the first to third flow paths in various operating states. The estimated first temperature, the estimated second temperature, and the estimated third temperature may be calculated based on the heat generation map. With this configuration, it is possible to accurately estimate the rate of increase of each of the first to third temperatures after the start of the first mode or the second mode.

[0011] In one embodiment of the present technology, when it is determined that the switching valve is in a slightly open state in the first mode, the control unit may execute a flow rate adjustment process to adjust the flow rate of at least one of the first pump and the second pump so that a pressure difference between a first pressure, which is a pressure on the first flow path side of the switching valve, and a second pressure, which is a pressure on the second flow path side of the switching valve, is reduced. The control unit may execute a process to change the switching valve to a state corresponding to a mode other than the first mode and then return the switching valve to a state corresponding to the first mode while executing the flow rate adjustment process. The control unit may execute a process to end the flow rate adjustment process. The switching valve generally includes a mechanism for closing the valve body by a pressing force such as a spring. When closing the valve body, the valve body is subjected to a pressure difference between the first pressure and the second pressure. This pressure difference varies in various ways depending on the operating conditions of the first flow path and the second flow path. Then, depending on the pressure fluctuation conditions, the valve body may not be completely closed and may be in a slightly open state, such as closing while being shifted obliquely. In the present technology, the valve body can be closed again in a state in which the pressure difference between the first pressure and the second pressure is reduced. Since the valve body can be closed when the effect of the pressure difference is small, it is possible to recover from a slightly open state.

[0012] In one embodiment of the present technology, in the flow rate adjustment process, when the first pressure is higher than the second pressure, at least one of a process of decreasing the flow rate of the first pump and a process of increasing the flow rate of the second pump may be executed. In the flow rate adjustment process, when the second pressure is higher than the first pressure, at least one of a process of decreasing the flow rate of the second pump and a process of increasing the flow rate of the first pump may be executed. With such a configuration, it is possible to reduce the pressure difference between the first pressure and the second pressure.

[0013] In one embodiment of the present technology, in the flow rate adjustment process, the first pump and the second pump may be stopped so that the first pressure and the second pressure are substantially balanced. With this configuration, the valve body can be closed again in a state where there is no pressure difference between the first pressure and the second pressure. It becomes possible to reliably recover from the slightly open state.

[0014] In one embodiment of the present technology, the switching valve may include a valve body that contacts the valve seat in the first mode. A first pressure may be applied to one surface of the valve body, and a second pressure may be applied to the other surface of the valve body. In the flow rate adjustment process, the flow rate of at least one of the first pump and the second pump may be adjusted so as to generate a pressure difference in a direction in which the valve body faces the valve seat. With this configuration, the operation of pressing the valve body against the valve seat can be assisted by the pressure difference between the first pressure and the second pressure. It becomes possible to reliably recover from the slightly open state. EXAMPLES

[0015] (Structure of Thermal Management System 100) A thermal management system 100 according to the embodiment will be described with reference to the drawings. The thermal management system 100 according to the embodiment is mounted on an electric vehicle, and heats and cools components provided in the electric vehicle, and air-conditions the interior of the vehicle, by circulating a heat medium such as an antifreeze or a refrigerant. As shown in FIG. 1, the thermal management system 100 includes a low-temperature radiator circuit 10 having a low-temperature radiator 42, a high-temperature radiator circuit 30 having a high-temperature radiator 94, a heat pump circuit 20 thermally interposed between the two radiator circuits 10 and 30, and a control device 98. These circuits 10, 20, and 30 are thermally connected, while the paths through which the heat medium flows are independent of each other. Although not particularly limited, the two radiator circuits 10 and 30 use antifreeze, such as long-life coolant, as the heat medium. On the other hand, the heat pump circuit 20 uses a refrigerant (heat medium for a refrigeration cycle) such as hydrofluorocarbon as the heat medium.

[0016] The low-temperature radiator circuit 10 and the heat pump circuit 20 are thermally connected via a chiller 70. The heat pump circuit 20 and the high-temperature radiator circuit 30 are thermally connected via a condenser 84. The chiller 70 functions as an evaporator in the heat pump circuit 20, and can transfer heat from the heat medium in the low-temperature radiator circuit 10 to the heat medium in the heat pump circuit 20. The condenser 84 functions as an evaporator in the heat pump circuit 20, and can transfer heat from the heat medium in the heat pump circuit 20 to the heat medium in the high-temperature radiator circuit 30.

[0017] (Configuration of low-temperature radiator circuit 10) The low-temperature radiator circuit 10 has a first circuit 12 that cools a secondary battery for a vehicle (hereinafter simply referred to as a battery) 66, and a second circuit 16 that cools heat-related devices.

[0018] The first circuit 12 is a circulation path that circulates the heat medium between the chiller 70 and the battery 66. The first circuit 12 mainly includes a battery path 13 and a chiller path 14. The battery path 13 includes, from the upstream side, a heater 64, a battery 66, and a first temperature sensor 61. The first temperature sensor 61 is a sensor for detecting the heat medium temperature at the outlet side of the battery 66. The battery 66 supplies power to a motor built into the transaxle 48 via an SPU 56 and a PCU 58, which will be described later. The battery 66 is cooled by heat exchange with the heat medium flowing through the battery path 13. The heater 64 is an electric heater, and can warm the battery 66 by heating the heat medium in the battery path 13 as necessary.

[0019] The chiller path 14 includes, from its upstream side, a first pump 68 that circulates the heat medium, and a chiller 70. The upstream end of the battery path 13 and the downstream end of the chiller path 14 are connected via a switching valve 40. In addition, the downstream end of the battery path 13 and the upstream end of the chiller path 14 are connected via a reservoir tank 69. The reservoir tank 69 includes a heat medium storage section for removing air bubbles from the heat medium.

[0020] The second circuit 16 mainly has a low-temperature radiator path 17 and a heat-related equipment path 18. The upstream end of the low-temperature radiator path 17 and the downstream end of the heat-related equipment path 18 are connected via a switching valve 40. The downstream end of the low-temperature radiator path 17 and the upstream end of the heat-related equipment path 18 are connected via a reservoir tank 69. The low-temperature radiator 42 is shared between the first circuit 12 and the second circuit 16. In this way, the low-temperature radiator circuit 10 can be efficiently configured.

[0021] The low-temperature radiator path 17 includes, from the upstream side, a low-temperature radiator 42 and a third temperature sensor 63 for detecting the heat medium temperature. The heat-related equipment path 18 includes, from the upstream side, an SPU (Smart Power Unit) 56 including a DC-DC converter, a PCU (Power Control Unit) 58 including an inverter, a second pump 60 for circulating the heat medium, a second temperature sensor 62 for detecting the heat medium temperature, and an oil cooler 54. The oil cooler 54 is a type of heat exchanger and is thermally connected to the transaxle 48 via an oil circulation path 50. The transaxle 48 includes a driving motor for driving the wheels, a reducer interposed between the driving motor and the wheels, and the like. The oil circulation path 50 includes an oil pump 52 and circulates oil, which is a heat medium, between the oil cooler 54 and the transaxle 48. As a result, the heat of the transaxle 48 is transferred to the oil cooler 54, and is further transferred from the oil cooler 54 to the heat medium of the second circuit 16.

[0022] The second circuit 16 further includes a bypass path 19. The bypass path 19 bypasses the low-temperature radiator 42. The bypass path 19 branches at a switching valve 40 at a connection portion between the low-temperature radiator path 17 and the heat-related equipment path 18, bypasses the low-temperature radiator 42, and merges with a reservoir tank 69 at the downstream end of the low-temperature radiator path 17.

[0023] The control device 98 is configured as a so-called computer having at least one processor and a memory. The memory stores a slightly open state determination program and a heat generation map. The slightly open state determination program is a program for determining whether the switching valve 40 is in a slightly open state. The processor executes a series of processes for determining the slightly open state of the switching valve 40 by executing the slightly open state determination program. The heat generation map is a map showing the amount of heat generated by the heat sources present in each of the first flow path C1, the second flow path C2, and the third flow path C3 in various operating states. The control device 98 also acquires first to third temperature measurement values ​​T1m to T3m from each of the first to third temperature sensors 61 to 63.

[0024] (Function of the switching valve 40) The switching valve 40 is a five-way flow control valve, and connects the two paths 13, 14 of the first circuit 12 and the three paths 17, 18, and 19 of the second circuit 16. The switching valve 40 is connected to a control device 98, and its operation is controlled by the control device 98. The structure of the switching valve 40 is not particularly limited, and may have various structures.

[0025] The switching valve 40 can switch the flow path between the first mode and the second mode. FIG. 1 shows the first mode. In the first mode, the first flow path C1 and the second flow path C2 are separated. The first flow path C1 and the second flow path C2 can operate independently of each other. The first flow path C1 is a flow path that circulates the heat medium between the chiller 70 and the battery 66 by using the first pump 68. The battery 66 can be cooled by the first flow path C1. The second flow path C2 is a flow path that circulates the heat medium between the low-temperature radiator 42 and some heat-related equipment (oil cooler 54, SPU 56, PCU 58) by using the second pump 60. The heat-related equipment can be cooled by the second flow path C2. The heat-related equipment generates a larger amount of heat than the battery 66. Therefore, the temperature of the heat medium in the second flow path C2 is higher than the temperature of the heat medium in the first flow path C1.

[0026] 2 shows the second mode. In the second mode, a part of the first flow path C1 and a part of the second flow path C2 are connected to form a third flow path C3. The third flow path C3 is a flow path that circulates a heat medium between the low-temperature radiator 42 and the chiller 70 using the first pump 68. The third flow path C3 allows the heat absorbed from the outside air by the low-temperature radiator 42 to be supplied to the chiller 70.

[0027] As shown in Fig. 1, the first pump 68 is disposed on the first flow path C1, and the second pump 60 is disposed on the second flow path C2. As shown in Fig. 2, the first temperature sensor 61 is disposed on the first flow path C1 that does not form the third flow path C3. The second temperature sensor 62 is disposed on the second flow path C2 that does not form the third flow path C3. The third temperature sensor 63 is disposed on the third flow path C3.

[0028] (Configuration of heat pump circuit 20) The heat pump circuit 20 mainly includes a main circuit 22 and a cooling path 24. The main circuit 22 is a circulation path that circulates a heat medium (refrigerant) between the chiller 70 and a condenser 84. The main circuit 22 further includes an expansion valve 72 and a compressor 82, and constitutes a so-called refrigeration cycle. In the main circuit 22, the heat medium circulates counterclockwise in FIG. 1. The main circuit 22 transfers heat from the low-temperature radiator circuit 10 connected to the chiller 70 to the high-temperature radiator circuit 30 connected to the condenser 84.

[0029] The cooling path 24 is provided in parallel to the chiller 70 and bypasses the chiller 70. The cooling path 24 is provided with an expansion valve 78, a cooling evaporator 76, and an EPR 74 (evaporator pressure regulator). A switching valve 80 is provided at the upstream end of the cooling path 24. The cooling evaporator 76 absorbs heat from the air inside the vehicle (including air introduced from the outside) into the heat medium of the heat pump circuit 20, thereby cooling the vehicle interior. The heat absorbed by the evaporator 76 is transferred from a condenser 84 to the high-temperature radiator circuit 30.

[0030] (Configuration of high temperature radiator circuit 30) The high-temperature radiator circuit 30 mainly includes a main circuit 32 and a heating path 34. The main circuit 32 of the high-temperature radiator circuit 30 is a circulation path that circulates a heat medium between a condenser 84 and a high-temperature radiator 94. The main circuit 32 is provided with a third pump 88 for circulating the heat medium. The main circuit 32 circulates the heat medium, thereby dissipating the heat transferred from the heat pump circuit 20 from the high-temperature radiator 94 to the outside air. The main circuit 32 is further provided with a heater 86.

[0031] The heating path 34 is provided in parallel to the high-temperature radiator 94, and bypasses the high-temperature radiator 94. A heater core 92 is provided in the heating path 34. A switching valve 90 is provided at the upstream end of the heating path 34. In the heater core 92, heat is dissipated from the heat medium flowing through the heating path 34 to the air inside the vehicle, thereby heating the vehicle interior.

[0032] (Determination process of slightly open state in first mode (first example)) The processing contents of the slightly open state determination program in the first mode when the switching valve 40 is in a slightly open state will be described. As a first example, a case in which the heat medium circulates in both the first flow path C1 and the second flow path C2 will be described with reference to FIG. 3. The horizontal axis of FIG. 3 is time, and the vertical axis is the temperature of the heat medium. The first temperature T1 is the measurement value of the first temperature sensor 61. The second temperature T2 is the measurement value of the second temperature sensor 62.

[0033] At time tt0, the switching valve 40 is switched so that the first flow path C1 and the second flow path C2 are separated (see FIG. 1). At time tt1, the first pump 68 and the second pump 60 start operating, causing the first temperature T1 and the second temperature T2 to start rising.

[0034] At time tt2, a predetermined time Pt ​​after time tt1, a first temperature measurement value T1m is acquired from the first temperature sensor 61, and a second temperature measurement value T2m is acquired from the second temperature sensor 62. The predetermined time Pt ​​is any time that can be determined in advance.

[0035] Further, the first temperature estimate T1e and the second temperature estimate T2e are acquired. The first temperature estimate T1e is an estimated temperature of the first temperature T1 at time tt2 when the switching valve 40 is not in a slightly open state. The second temperature estimate T2e is an estimated temperature of the second temperature T2 at time tt2 when the switching valve 40 is not in a slightly open state. The first temperature estimate T1e and the second temperature estimate T2e can be obtained based on the above-mentioned heat generation map and the presence or absence of the operation of the first pump 68 and the second pump 60. The first temperature estimate T1e and the second temperature estimate T2e may be obtained in various ways. In this embodiment, as shown by the dotted lines in FIG. 3, the estimated graphs G1 and G2 are obtained. The estimated graphs G1 and G2 are estimated values ​​of the rising slopes of the first temperature T1 and the second temperature T2 when the switching valve 40 is not in a slightly open state. Then, a first temperature estimate T1e and a second temperature estimate T2e at time tt2 are obtained based on the estimated graphs G1 and G2.

[0036] Next, it is determined whether the first temperature measurement value T1m is greater than the first temperature estimation value T1e by more than a predetermined threshold value TH1. Specifically, it is determined whether the first temperature measurement value T1m is greater than the first temperature estimation value T1e, and whether the difference value DV1 between the first temperature measurement value T1m and the first temperature estimation value T1e is greater than a predetermined threshold value TH1. It is also determined whether the second temperature measurement value T2m is smaller than the second temperature estimation value T2e by more than a predetermined threshold value TH2. Specifically, it is determined whether the second temperature measurement value T2m is smaller than the second temperature estimation value T2e, and whether the difference value DV2 between the second temperature measurement value T2m and the second temperature estimation value T2e is greater than a predetermined threshold value TH2. When the first temperature measurement T1m is greater than the first temperature estimate T1e by more than a predetermined threshold TH1, and the second temperature measurement T2m is smaller than the second temperature estimate T2e by more than a predetermined threshold TH2, it can be determined that the valve is in a slightly open state.

[0037] The principle of determining the slightly open state will be described. When the switching valve 40 is in the slightly open state, the heat medium is slightly mixed between the first flow path C1 and the second flow path C2. Therefore, heat is transferred from the high-temperature heat medium in the second flow path C2 to the low-temperature heat medium in the first flow path C1. Due to this heat transfer, the actually measured rising slope of the heat medium temperature in the second flow path C2 (the slope of the second temperature T2) is smaller than the rising slope estimated when the switching valve 40 is normal (the slope of the estimated graph G2). On the other hand, the actually measured rising slope of the heat medium temperature in the first flow path C1 (the slope of the first temperature T1) is larger than the rising slope estimated when the switching valve 40 is normal (the slope of the estimated graph G1).

[0038] That is, by detecting a combination of gradient changes in which the rate of increase of the second temperature T2 becomes smaller than normal and the rate of increase of the first temperature T1 becomes larger than normal, it is possible to detect the occurrence of a transfer of heat from the second flow path C2 to the first flow path C1. Then, by detecting that the decrease in the rate of increase of the second temperature T2 exceeds a predetermined threshold value TH2 and that the increase in the rate of increase of the first temperature T1 exceeds a predetermined threshold value TH1, it is possible to detect the occurrence of a non-negligible transfer of heat. As a result, it is possible to determine that the switching valve 40 is in a slightly open state.

[0039] The predetermined thresholds TH1 and TH2 may be determined in advance based on the heat capacity of the first flow path C1 and the second flow path C2. For example, an allowable heat amount is calculated, which is the maximum amount of heat allowed to move from the second flow path C2 to the first flow path C1 during a predetermined time Pt. Then, the amount of temperature rise of the heat medium when the allowable heat amount is provided to the first flow path C1 is calculated from the heat capacity of the first flow path C1, and the amount of temperature drop of the heat medium when the allowable heat amount is taken from the second flow path C2 is calculated from the heat capacity of the second flow path C2. This amount of temperature rise may be set as the predetermined threshold TH1, and the amount of temperature drop may be set as the predetermined threshold TH2.

[0040] Also, when the switching valve 40 is broken and the first flow path C1 and the second flow path C2 are conductive, this can be easily distinguished from the slightly open state. An example of a temperature graph at the time of a failure is shown in FIG. 4. At time tt1, when the first pump 68 and the second pump 60 start to operate, the high-temperature heat medium in the second flow path C2 and the low-temperature heat medium in the first flow path C1 mix, causing the second temperature T2 to drop instantaneously (see region R1). Then, at time tt3, the first temperature T1 and the second temperature T2 become equal and are saturated. By detecting such a characteristic temperature change, a failure of the switching valve 40 can be determined.

[0041] (Determination process for slightly open state in first mode (second example)) As a second example in the first mode, the process of the slightly open state determination program in the case where the first flow path C1 is stopped and the heat medium circulates only through the second flow path C2 will be described.

[0042] At time tt1 in FIG. 5, the second pump 60 starts to operate. At time tt2, as shown by the dotted lines, the estimated graphs G1 and G2 are obtained. The estimated graph G2 rises due to heat recovery because the second pump 60 is operating. On the other hand, the estimated graph G1 remains at the initial temperature because the first pump 68 is stopped. It is a constant value. However, since the switching valve 40 is in a slightly open state, the actually measured rising slope of the heat medium temperature in the second flow path C2 (the slope of the second temperature T2) is smaller than the rising slope (the slope of the estimated graph G2) estimated when the switching valve 40 is normal. On the other hand, the actually measured rising slope of the heat medium temperature in the first flow path C1 (the slope of the first temperature T1) is larger than the rising slope (the slope of the estimated graph G1) estimated when the switching valve 40 is normal. It is then determined that the first measured temperature value T1m is larger than the first estimated temperature value T1e by more than the predetermined threshold value TH1, and the second measured temperature value T2m is smaller than the second estimated temperature value T2e by more than the predetermined threshold value TH2.

[0043] From the above, it can be seen that even when either the first flow path C1 or the second flow path C2 is stopped, in the slightly open state, it is possible to detect a combination of gradient changes in which the rate of increase of the second temperature T2 is smaller than normal and the rate of increase of the first temperature T1 is larger than normal. Therefore, it is possible to determine that the switching valve 40 is in the slightly open state.

[0044] (Determination process of slightly open state in second mode) The processing contents of the slightly open state determination program in the case where the switching valve 40 is in the slightly open state in the second mode will be described. As an example, a case where the third temperature T3 measured by the third temperature sensor 63 is sufficiently higher than the first temperature T1 and the second temperature T2 will be described. In addition, a case where the heat medium does not circulate in the first flow path C1 and the second flow path C2 that do not form the third flow path C3 will be described.

[0045] At time tt0 in Fig. 6, the switching valve 40 is switched so that the third flow path C3 (see Fig. 2) is formed. At time tt11, the first pump 68 operates to start circulating the heat medium through the third flow path C3, and the third temperature T3 starts to rise.

[0046] At time tt12, as shown by the dotted line, estimated graphs G1 to G3 are obtained. The estimated graphs G1 to G3 are estimated values ​​of the rising gradients of the first temperature T1 to the third temperature T3 when the switching valve 40 is normal. Since the heat medium circulates through the third flow path C3, the estimated graph G3 rises. On the other hand, since the heat medium does not circulate through the first flow path C1 and the second flow path C2, the estimated graphs G1 and G2 remain constant at the initial temperature. In addition, the first temperature measurement value T1m to the third temperature measurement value T3m and the first temperature estimation value T1e to the third temperature estimation value T3e are obtained. The method of obtaining these values ​​is the same as that described above, so a description thereof will be omitted.

[0047] Then, when the third temperature measurement value T3m is smaller than the third temperature estimation value T3e by more than a predetermined threshold value TH3, the first temperature measurement value T1m is larger than the first temperature estimation value T1e by more than a predetermined threshold value TH1, and the second temperature measurement value T2m is larger than the second temperature estimation value T2e by more than a predetermined threshold value TH2, it can be determined that the switching valve 40 is in the slightly open state. This is because, when the switching valve 40 is in the slightly open state, heat is transferred from the high-temperature heat medium in the third flow path C3 to the low-temperature heat medium in the first flow path C1 and the second flow path C2. This heat transfer causes a combination of gradient changes in which the rate of increase of the third temperature T3 is smaller than normal, and the rates of increase of the first temperature T1 and the second temperature T2 are larger than normal. By detecting this combination of gradient changes, it can be determined that the switching valve 40 is in the slightly open state. EXAMPLES

[0048] In the second embodiment, a process for correcting the slightly open state will be described. The process for correcting the slightly open state is a process for correcting the slightly open state when it is determined that the switching valve 40 is in the slightly open state in the first embodiment. This process is executed by a slightly open state determination program of the control device 98. As an example, the process when it is determined that the valve is in the slightly open state in the first mode will be described below.

[0049] The processor of the control device 98 starts the flow shown in Fig. 7 when it is determined that the valves are slightly open in the first mode. In step S2, the processor determines whether the first pump 68 and the second pump 60 can be stopped. For example, when the first temperature measurement value T1m and the second temperature measurement value T2m have a sufficient margin with respect to the required heat medium temperature value, it can be determined that the pumps can be stopped. If the pumps cannot be stopped, the process proceeds to step S8.

[0050] In step S8, a pressure calculation process is performed. Specifically, a first pressure P1, which is the pressure on the first flow path C1 side of the switching valve 40, and a second pressure P2, which is the pressure on the second flow path C2 side, are calculated. The first pressure P1 can be calculated using the relationship of "first pressure P1 = (discharge pressure D1 of the first pump 68) - (pressure loss DR1 from the first pump 68 to the switching valve 40)". The pressure loss DR1 is the sum of a component pressure loss due to a component (chiller 70) on the path from the first pump 68 to the switching valve 40 and a piping pressure loss due to the piping (first circuit 12). Similarly, the second pressure P2 can be calculated using the relationship of "second pressure P2 = (discharge pressure D2 of the second pump 60) - (pressure loss DR2 from the second pump 60 to the switching valve 40)". The pressure loss DR2 is the sum of the component pressure loss due to the component (oil cooler 54) on the path from the second pump 60 to the switching valve 40 and the piping pressure loss due to the piping (heat-related equipment path 18). The discharge pressure, component pressure loss, and piping pressure loss are values ​​determined by the duty (flow rate) and the heat medium temperature.

[0051] Fig. 8 shows an example of calculation of the first pressure P1 and the second pressure P2. Fig. 8 shows an example in which the first pressure P1 is higher than the second pressure P2. The difference between the first pressure P1 and the second pressure P2 is the pressure difference PD.

[0052] In steps S10 to S16, a flow rate adjustment process is performed. The flow rate adjustment process is a process for adjusting the flow rate of at least one of the first pump 68 and the second pump 60 so as to reduce the pressure difference PD. There may be various control methods for reducing the pressure difference PD. For example, the pressure difference PD may be controlled so as to be smaller than a predetermined threshold value, the pressure difference PD may be controlled so as to be reduced by a predetermined percentage, or the pressure difference PD may be controlled so as to be almost zero. A specific description will be given below.

[0053] In step S10, it is determined whether the pump with the higher pressure of the first pressure P1 and the second pressure P2 is on full duty. If the determination is negative (S10: NO), the process proceeds to step S14, where the flow rate of the pump with the higher pressure is reduced to reduce the pressure difference PD. In the example of FIG. 8, the flow rate of the first pump 68 is reduced to reduce the first pressure P1, thereby reducing the pressure difference PD. On the other hand, if the determination is positive (S10: YES), it is determined that there is no margin for the heat medium temperature request, and it is difficult to reduce the flow rate of the pump with the higher pressure, and the process proceeds to step S12.

[0054] In step S12, it is determined whether the pump on the lower pressure side is on full duty. If the determination is negative (S12: NO), the process proceeds to step S16, where the flow rate of the pump on the lower pressure side is increased to reduce the pressure difference PD. In the example of FIG. 8, the flow rate of the second pump 60 is increased to raise the second pressure P2, thereby reducing the pressure difference PD. On the other hand, if the determination is positive (S12: YES), it is determined that it is difficult to increase the flow rate of the pump on the lower pressure side, and the process proceeds to step S14. In step S14, the flow rate of the pump on the higher pressure side is reduced to reduce the pressure difference PD. Then, the process proceeds to step S20.

[0055] On the other hand, if it is determined in step S2 that the first pump 68 and the second pump 60 can be stopped, the process proceeds to step S18, where the first pump 68 and the second pump 60 are stopped. As a result, the first pressure P1 and the second pressure P2 are no longer generated, so that the pressure difference PD can be balanced. Then, the process proceeds to step S20.

[0056] In step S20, the switching valve 40 is controlled to open and close. Specifically, with the pressure difference PD being reduced, the switching valve 40 is changed to a state corresponding to a mode other than the first mode, and then a process is executed to return the switching valve 40 to a state corresponding to the first mode. This allows the switching valve 40 to be restored from the slightly open state to the normal state. Then, the process proceeds to step S22, where the first pump 68 and the second pump 60 are returned to their specified operating states. This completes the process of correcting the slightly open state.

[0057] The effect of the opening and closing control of step S20 will be described. A switching valve generally has a mechanism for closing the valve body by the pressing force of a spring or the like. The same is true for a rotating structure and a structure with a slit. When closing the valve body, a pressure difference PD between the first pressure P1 and the second pressure P2 is received. This pressure difference PD varies in various ways depending on the operating conditions of the first flow path C1 and the second flow path C2. For example, when both the first pump 68 and the second pump 60 are operating, the pressure of the pump closer to the switching valve 40 is always applied to the switching valve 40. Also, when only one pump is operating, only the pressure from the pump in operation is applied to the switching valve 40. And when the first pump 68 and the second pump 60 perform fine flow rate control, the first pressure P1 and the second pressure P2 vary transiently. Since the valve body must close while receiving the first pressure P1 and the second pressure P2, the operation of the valve body may be transient, and the valve body may close while shifted at an angle, resulting in a slightly open state instead of closing completely. This slightly open state is not a malfunction and can be corrected. Therefore, by performing a process to reduce the pressure difference PD (steps S10 to S18) and then a process to open and close the valve body (step S20), the valve body can be closed again while the influence of the pressure difference PD is small, making it possible to recover from the slightly open state.

[0058] The correction process of the slightly open state in the first mode has been described above, but the correction process of the slightly open state in the second mode is similar. That is, in step S8, the first pressure P1 on the first flow path C1 side where the third flow path C3 is not formed, the second pressure P2 on the second flow path C2 side where the third flow path C3 is not formed, and the third pressure P3 which is the pressure on the third flow path C3 side may be calculated. Then, in steps S10 to S16, the flow rate of the first pump 68 may be controlled so that the pressure difference PD between the first pressure P1 and the third pressure P3 becomes small. Other processing contents are the same as the correction process in the first mode, so the description will be omitted.

[0059] (Modification of the second embodiment) The switching valve 40 may include a valve body that contacts the valve seat in the first mode. A first pressure P1 may be applied to one surface of the valve body, and a second pressure P2 may be applied to the other surface of the valve body. In the flow rate adjustment process, the flow rate of at least one of the first pump 68 and the second pump 60 may be adjusted so as to generate a pressure difference PD in the direction in which the valve body faces the valve seat.

[0060] For example, assume that the direction of the force that the valve body receives from the first pressure P1 is a direction away from the valve seat, and the direction of the force that the valve body receives from the second pressure P2 is a direction toward the valve seat. In this case, if the first pressure P1 is greater than the second pressure P2 as shown in FIG. 8, a force that opens the valve body is generated by the pressure difference PD, so that the valve is likely to be in a slightly open state. Therefore, in the flow rate adjustment process, it is sufficient to control the second pressure P2 to be greater than the first pressure P1. This makes it possible to generate a force that closes the valve body by the pressure difference PD. The operation of pressing the valve body against the valve seat can be assisted by the pressure difference PD, so it is possible to reliably recover from the slightly open state.

[0061] Although the embodiments have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or drawings achieves multiple objectives simultaneously, and achieving one of the objectives itself has technical utility.

[0062] (Modification) In this embodiment, the case where the first and second modes are switched by the switching valve 40, which is a five-way flow control valve, has been described, but the present invention is not limited to this. The number and arrangement of the switching valves can be freely set. For example, as in the low-temperature radiator circuit 10a shown in FIG. 9, the first and second modes may be switched by two switching valves, a first switching valve 221 and a second switching valve 222. The first switching valve 221 and the second switching valve 222 are three-way flow control valves. The first switching valve 221 is provided at the connection portion between the first circuit 12 and the connection circuit 210. The second switching valve 222 is provided at the branch portion of the bypass path 19 of the second circuit 16. Even in the arrangement of the switching valves as shown in FIG. 6, it is possible to apply the process of determining the slightly open state (Example 1) and the process of correcting the slightly open state (Example 2).

[0063] In this embodiment, the structure in which the first circuit 12 and the second circuit 16 are connected via the reservoir tank 69 has been described, but the present invention is not limited to this structure, and various connection structures can be used. For example, instead of the reservoir tank 69, a 3-way pipe may be used for connection.

[0064] The method of acquiring the first to third temperature estimated values ​​T1e to T3e is not limited to the method using the estimation graphs G1 to G3, and various methods can be used. For example, a map of temperature estimated values ​​may be used instead of a graph.

[0065] 7, the flow rate adjustment process is described with respect to a case where the flow rate of one of the first pump 68 and the second pump 60 is adjusted, but the present invention is not limited to this. The flow rates of both the first pump 68 and the second pump 60 may be adjusted.

[0066] The positions of the first temperature sensor 61 to the third temperature sensor 63 in this embodiment are merely an example, and the present invention is not limited to these positions.

[0067] The thermal management system 100 is mounted on an electric vehicle, but is not limited to this. It can also be used as a stationary type thermal management system 100. Also, the thermal management system 100 is equipped with a battery cooling circuit (battery cooling system) that cools the battery 66 as a battery, but it can also be used as a cooling system for other batteries such as fuel cells.

[0068] Although the thermal management system 100 includes the heat pump circuit 20 and the high-temperature radiator circuit 30, the system does not necessarily have to include these. Any system having the intention of cooling the battery may be used.

[0069] The control device 98 is an example of a control unit. The time tt2 is an example of a first predetermined time. The time tt12 is an example of a second predetermined time. [Explanation of symbols]

[0070] 10: Low temperature radiator circuit 12: First circuit 16: Second circuit 40: Switching valve 60: Second pump 61: Temperature sensor 62: Second temperature sensor 63: Third temperature sensor 68: First pump 98: Control device 100: Thermal management system C1: First flow path C2: Second flow path C3: Third flow path T1m-T3m: First temperature measurement value-third temperature measurement value T1e-T3e: First temperature estimate value-third temperature estimate value

Claims

1. A thermal management system for a vehicle comprising a chiller, a battery, a radiator, and a PCU, a first circulation path for circulating a heat medium between the chiller and the battery; A first pump is disposed on the first circulation path and circulates the heat medium through the first circulation path; A first temperature sensor is disposed on the first circulation path and is capable of measuring a first temperature of the heat medium on an outlet side of the battery; A second circulation path for circulating the heat transfer medium between the radiator and the PCU; A second pump is disposed on the second circulation path and circulates the heat medium through the second circulation path; A second temperature sensor is disposed on the second circulation path and is capable of measuring a second temperature of the heat medium on an outlet side of the PCU; a switching valve configured to be switchable between a first mode in which the first circulation path and the second circulation path are separated and a second mode in which a third circulation path is formed by a part of the first circulation path and a part of the second circulation path being connected; a control unit that determines whether the switching valve is in a slightly open state in the first mode; Equipped with the third circulation path is a circulation path that circulates the heat medium between the radiator and the chiller, and the battery and the PCU are not disposed on the circulation path; The slightly open state in the first mode is a state in which the heat medium is mixed between the first circulation path and the second circulation path, the second temperature is greater than the first temperature; In the first mode, the control unit: At a first predetermined time when a predetermined time has elapsed since at least one of the first temperature and the second temperature started to rise, a measured value of the first temperature is obtained from the first temperature sensor, and a measured value of the second temperature is obtained from the second temperature sensor; acquiring an estimated value of the first temperature and an estimated value of the second temperature at the first predetermined time in a case where the switching valve is not in a slightly open state in the first mode; when the measured value of the first temperature is greater than the estimated value of the first temperature by exceeding a predetermined threshold value and the measured value of the second temperature is smaller than the estimated value of the second temperature by exceeding the predetermined threshold value, it is determined that the switching valve is in a slightly open state in the first mode. Thermal management system.

2. The thermal management system further includes a third temperature sensor arranged on the third circulation path and capable of measuring a third temperature of the heat medium on an outlet side of the radiator, the first temperature sensor is disposed on the first circulation path that does not form the third circulation path, the second temperature sensor is disposed on the second circulation path that does not form the third circulation path, When the third temperature is higher than the first temperature and the second temperature, the control unit is configured to determine whether or not the switching valve is in a slightly open state in the second mode, The slightly open state in the second mode is a state in which the heat medium is mixed between the first circulation path and the second circulation path, which do not form the third circulation path, and the third circulation path, and In the second mode, the control unit: At a second predetermined time when a predetermined time has elapsed since the third temperature started to rise, a measurement value of the first temperature is obtained from the first temperature sensor, a measurement value of the second temperature is obtained from the second temperature sensor, and a measurement value of the third temperature is obtained from the third temperature sensor; acquiring an estimated value of the first temperature, an estimated value of the second temperature, and an estimated value of the third temperature at the second predetermined time when the switching valve is not in the slightly open state in the second mode; when the measured value of the first temperature is greater than the estimated value of the first temperature by more than the predetermined threshold, the measured value of the second temperature is greater than the estimated value of the second temperature by more than the predetermined threshold, and the measured value of the third temperature is smaller than the estimated value of the third temperature by more than the predetermined threshold, the switching valve is determined to be in a slightly open state in the second mode. The thermal management system of claim 1 .

3. the thermal management system includes a heat generation map indicating heat amounts of heat sources, including the battery and the PCU, present in each of the first and second circulation paths in various operating states, and indicating heat absorbed from outside air by the radiator in the third circulation path; The thermal management system of claim 2 , wherein the estimate of the first temperature, the estimate of the second temperature, and the estimate of the third temperature are determined based on the heat map.

4. When it is determined that the switching valve is in the slightly open state in the first mode, the control unit: executing a flow rate adjustment process for adjusting a flow rate of at least one of the first pump and the second pump so that a pressure difference between a first pressure, which is a pressure on the first circulation path side of the switching valve, and a second pressure, which is a pressure on the second circulation path side of the switching valve, becomes small; While the flow rate adjustment process is being performed, a process is performed in which the switching valve is changed to a state corresponding to a mode other than the first mode, and then the switching valve is returned to a state corresponding to the first mode; The thermal management system according to claim 1 , further comprising a process for terminating the flow rate adjustment process.

5. In the flow rate adjustment process, When the first pressure is higher than the second pressure, at least one of a process of decreasing a flow rate of the first pump and a process of increasing a flow rate of the second pump is executed; The thermal management system of claim 4 , further comprising: when the second pressure is higher than the first pressure, at least one of a process for reducing a flow rate of the second pump and a process for increasing a flow rate of the first pump is executed.

6. The thermal management system according to claim 4 , wherein in the flow rate adjustment process, the first pump and the second pump are stopped so that the first pressure and the second pressure are substantially in equilibrium.

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