Heat management system

Abstract

[Problem] To provide a heat management system capable of avoiding high-load operation and blowout temperature restriction. [Solution] A heat management system 1 comprises: a refrigerant circuit 10 that has a high-temperature-side heat exchanger 12 as a condenser and a second low-temperature-side heat exchanger 142 as an evaporator; a high-temperature-side heat medium circuit 20 which allows circulation therethrough of a heat medium that exchanges heat with a refrigerant in the high-temperature-side heat exchanger 12; and a low-temperature-side heat medium circuit 30 which allows circulation therethrough of the heat medium that exchanges heat with the refrigerant in the second low-temperature-side heat exchanger 142. At least a portion of the heat medium heated in the high-temperature-side heat exchanger 12 is caused to flow from the high-temperature-side heat medium circuit 20 to the low-temperature-side heat medium circuit 30, and the heat of the heat medium flowing from the high-temperature-side heat medium circuit 20 to the low-temperature-side heat medium circuit 30 is caused to be absorbed by the refrigerant in the second low-temperature-side heat exchanger 142.

Description

Thermal management system

[0001] The present invention relates to a thermal management system.

[0002] Conventionally, a thermal management system that uses a heat medium that has exchanged heat with a refrigerant has been known. For example, Patent Document 1 discloses a thermal management system that heats a battery by flowing a part of the heat medium flowing through a high-temperature side heat medium circuit to a low-temperature side heat medium circuit.

[0003] Japanese Patent No. 6271222

[0004] An object of the present invention is to provide a thermal management system that can avoid restrictions on the blowing temperature and high-load operation.

[0005] According to one aspect of the present invention, a thermal management system includes a refrigerant circuit having a condenser and an evaporator, a high-temperature side heat medium circuit through which a heat medium that exchanges heat with the refrigerant in the condenser circulates, and a low-temperature side heat medium circuit through which a heat medium that exchanges heat with the refrigerant in the evaporator circulates. The thermal management system is configured such that at least a part of the heat medium heated by the condenser flows from the high-temperature side heat medium circuit to the low-temperature side heat medium circuit, and the heat of the heat medium flowing from the high-temperature side heat medium circuit to the low-temperature side heat medium circuit is absorbed by the refrigerant in the evaporator.

[0006] According to the present invention, a thermal management system that can avoid restrictions on the blowing temperature and high-load operation can be provided.

[0007] FIG. 1 is a circuit diagram showing an example of the configuration of a thermal management system. FIG. 2 is a block diagram showing a control device of the thermal management system. FIG. 3 is a flowchart showing an example of the execution process of the water mixing heating mode.

[0008] [System Configuration] <System Overview> Figure 1 is an explanatory diagram showing a schematic of the thermal management system 1. The thermal management system 1 is installed in a vehicle. The vehicle is preferably a vehicle equipped with a battery for driving. The vehicle may be, for example, an electric vehicle (BEV: Battery Electric Vehicle), a hybrid vehicle (HEV: Hybrid Electric Vehicle), a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle), or a fuel cell vehicle (FCEV: Fuel Cell Electric Vehicle).

[0009] The thermal management system 1 includes a refrigerant circuit 10 through which a refrigerant circulates. The refrigerant is not limited to this, but for example, hydrofluoroolefins may be used.

[0010] The thermal management system 1 includes a high-temperature side heat transfer medium circuit 20 and a low-temperature side heat transfer medium circuit 30, through which a fluid heat transfer medium, such as coolant, circulates. Although not shown in the figures, the thermal management system 1 also includes a battery temperature control circuit, a motor temperature control circuit, and an outdoor heat exchange circuit.

[0011] The thermal management system 1 includes an HVAC (Heating, Ventilation, and Air Conditioning) unit 100 as an air conditioning unit.

[0012] <Refrigerant Circuit> The refrigerant circuit 10 includes a compressor 11, a high-temperature side heat exchanger 12 as a condenser, pressure reducing devices 13a and 13b such as expansion valves, a first low-temperature side heat exchanger 141 as an evaporator, and a second low-temperature side heat exchanger 142 as an evaporator.

[0013] The compressor 11 compresses the gaseous refrigerant to a high temperature and pressure before discharging it. The high-temperature heat exchanger 12 condenses the gaseous refrigerant compressed by the compressor 11 to release heat. The pressure reducing devices 13a and 13b expand the liquid refrigerant to a low pressure. The first low-temperature heat exchanger 141 and the second low-temperature heat exchanger 142 evaporate the liquid refrigerant, which has been reduced to a low temperature and low pressure, to absorb heat. The refrigerant circuit 10 functions as a heat pump, circulating the refrigerant and repeatedly compressing, condensing, expanding, and evaporating it.

[0014] The high-temperature side heat exchanger 12 includes a refrigerant passage 12a through which the refrigerant circulating in the refrigerant circuit 10 passes, and a heat medium passage 12b through which the heat medium circulating in the high-temperature side heat medium circuit 20 passes.

[0015] In the high-temperature side heat exchanger 12, heat exchange occurs between the heat transfer medium circulating in the high-temperature side heat transfer medium circuit 20 and the refrigerant. As a result, the heat transfer medium circulating in the high-temperature side heat transfer medium circuit 20 can be heated in the high-temperature side heat exchanger 12.

[0016] The first low-temperature side heat exchanger 141 includes a refrigerant passage 141a through which the refrigerant circulating in the refrigerant circuit 10 passes, and a heat medium passage 141b through which the heat medium circulating in the low-temperature side heat medium circuit 30 passes.

[0017] In the first low-temperature side heat exchanger 141, heat exchange occurs between the heat transfer medium circulating in the low-temperature side heat transfer medium circuit 30 and the refrigerant. As a result, the heat transfer medium circulating in the low-temperature side heat transfer medium circuit 30 can be heated or cooled in the first low-temperature side heat exchanger 141.

[0018] The second low-temperature side heat exchanger 142 includes a refrigerant passage 142a through which the refrigerant circulating in the refrigerant circuit 10 passes, and a heat medium passage 142b through which the heat medium circulating in the low-temperature side heat medium circuit 30 passes.

[0019] In the second low-temperature heat exchanger 142, heat exchange occurs between the heat transfer medium circulating in the low-temperature heat transfer medium circuit 30 and the refrigerant. As a result, the heat transfer medium circulating in the low-temperature heat transfer medium circuit 30 can be heated or cooled in the second low-temperature heat exchanger 142.

[0020] The discharge side of the compressor 11 is connected to the inlet of the refrigerant passage 12a of the high-temperature heat exchanger 12 via the refrigerant passage 10a. The outlet of the refrigerant passage 12a of the high-temperature heat exchanger 12 is connected to the inlet of the refrigerant passage 141a of the first low-temperature heat exchanger 141 via the refrigerant passage 10b, branch point a, and the downstream refrigerant passage 10c. A pressure reducing device 13a is installed along the path of the refrigerant passage 10c. The outlet of the refrigerant passage 141a of the first low-temperature heat exchanger 141 is connected to the suction side of the compressor 11 via the refrigerant passage 10d, confluence point b, and the downstream refrigerant passage 10e. An accumulator 15 is installed along the path of the refrigerant passage 10e.

[0021] Furthermore, the outlet of the refrigerant passage 12a of the high-temperature heat exchanger 12 is connected to the inlet of the refrigerant passage 142a of the second low-temperature heat exchanger 142 via the refrigerant flow path 10b, branch point a, and the downstream refrigerant flow path 10f. A pressure reducing device 13b is installed along the path of the refrigerant flow path 10f. The outlet of the refrigerant passage 142a of the second low-temperature heat exchanger 142 is connected to the suction side of the compressor 11 via the refrigerant flow path 10g, confluence point b, and the downstream refrigerant flow path 10e.

[0022] <High-Temperature Side Heat Transfer Circuit> The high-temperature side heat transfer circuit 20 includes the heat transfer passage 12b of the high-temperature side heat exchanger 12, a heater core 21 that heats the air supplied to the vehicle interior, and a flow rate adjustment unit V20 such as a three-way valve. The high-temperature side heat transfer circuit 20 is a circuit through which the heat transfer medium that exchanges heat with the refrigerant in the high-temperature side heat exchanger 12 circulates. The high-temperature side heat transfer circuit 20 can be used to heat the vehicle interior by making the heater core 21 function.

[0023] The outlet of the heat transfer medium passage 12b of the high-temperature heat exchanger 12 is connected to the inlet side 21a of the heater core 21 by heat transfer medium passages 20a and 20b via a flow rate adjustment unit V20. That is, the flow rate adjustment unit V20 is located downstream of the high-temperature heat exchanger 12. The outlet side 21b of the heater core 21 is connected to the inlet of the heat transfer medium passage 12b of the high-temperature heat exchanger 12 by a heat transfer medium passage 20c, a confluence point c, and a heat transfer medium passage 20d downstream thereof.

[0024] A circulation pump P20 for circulating the heat transfer medium is installed along the path of the heat transfer medium flow path 20d. The heat transfer medium is pushed out by the circulation pump P20 and circulates through the high-temperature side heat transfer medium circuit 20. The heat transfer medium, which is heated by receiving heat from the refrigerant circuit 10 as it passes through the heat transfer medium passage 12b of the high-temperature side heat exchanger 12, is supplied to the heater core 21 from the inlet side 21a and passes through the heater core 21. At this time, the heater core 21 functions as the heat transfer medium releases heat in the heater core 21. After passing through the heater core 21, the heat transfer medium discharged from the outlet side 21b returns to the heat transfer medium passage 12b of the high-temperature side heat exchanger 12.

[0025] The flow rate adjustment unit V20 is connected to the confluence point d of the low-temperature side heat transfer medium circuit 30 by the heat transfer medium flow path 20e. Therefore, the heat transfer medium that flows from the high-temperature side heat exchanger 12 to the flow rate adjustment unit V20 via the heat transfer medium flow path 20a can be branched into the heat transfer medium flow path 20b and the heat transfer medium flow path 20e, allowing it to flow to the low-temperature side heat transfer medium circuit 30 and the heater core 21. Thus, at least a portion of the heat transfer medium heated in the high-temperature side heat exchanger 12 can flow from the high-temperature side heat transfer medium circuit 20 to the low-temperature side heat transfer medium circuit 30.

[0026] The flow rate adjustment unit V20 adjusts the flow rate of the heat transfer medium flowing to the heater core 21 and the flow rate of the heat transfer medium flowing to the low-temperature heat transfer medium circuit 30. In other words, the flow rate adjustment unit V20 adjusts the amount of heat transfer medium flowing from the high-temperature heat transfer medium circuit 20 to the low-temperature heat transfer medium circuit 30 downstream of the high-temperature heat exchanger 12.

[0027] <Low Temperature Heat Transfer Circuit> The low temperature heat transfer circuit 30 includes the heat transfer passage 141b of the first low temperature heat exchanger 141, the heat transfer passage 142b of the second low temperature heat exchanger 142, a cooler core 31 that cools the air supplied to the vehicle interior, and a flow rate adjustment unit V30 such as a three-way valve. The low temperature heat transfer circuit 30 is a circuit through which the heat transfer medium that exchanges heat with the refrigerant in the low temperature heat exchanger 14 circulates. The low temperature heat transfer circuit 30 can be used to activate the cooler core 31 to cool or dehumidify the vehicle interior.

[0028] The outlet of the heat transfer medium passage 141b of the first low-temperature heat exchanger 141 is connected to the inlet side 31a of the cooler core 31 by a heat transfer medium flow path 30a. The outlet side 31b of the cooler core 31 is connected to the inlet of the heat transfer medium passage 141b of the first low-temperature heat exchanger 141 by a heat transfer medium flow path 30b. A circulation pump P30 for circulating the heat transfer medium is installed along the path of the heat transfer medium flow path 30b.

[0029] In the heat transfer fluid passages 30a and 30b, the heat transfer fluid circulates due to the pushing of the heat transfer fluid by the circulation pump P30. As the heat transfer fluid passes through the heat transfer fluid passage 141b of the first low-temperature heat exchanger 141, it is cooled by releasing heat to the refrigerant circuit 10. The cooled heat transfer fluid is supplied to the cooler core 31 from the inlet side 31a and passes through the cooler core 31. At this time, the cooler core 31 functions as the heat transfer fluid absorbs heat in the cooler core 31. After passing through the cooler core 31, the heat transfer fluid discharged from the outlet side 31b heads towards the heat transfer fluid passage 141b of the first low-temperature heat exchanger 141.

[0030] The outlet of the heat transfer medium passage 142b of the second low-temperature heat exchanger 142 is connected to the inlet of the heat transfer medium passage 142b of the second low-temperature heat exchanger 142 via the heat transfer medium passages 30c and 30d, the confluence point d, and the heat transfer medium passage 30e downstream thereof, through the flow rate adjustment unit V30. A circulation pump P31 for circulating the heat transfer medium is installed along the path of the heat transfer medium passage 30e.

[0031] In the heat transfer fluid passages 30c, 30d, and 30e, the heat transfer fluid circulates due to the pushing of the heat transfer fluid by the circulation pump P31. As the heat transfer fluid passes through the heat transfer fluid passage 142b of the second low-temperature heat exchanger 142, it is heated by absorbing heat from the refrigerant circuit 10, or cooled by releasing heat back into the refrigerant circuit 10. Releasing the heat from the heated heat transfer fluid back into the refrigerant circuit 10 enables heat pump operation at extremely low temperatures.

[0032] Furthermore, the flow rate adjustment unit V30 is connected to the confluence point c of the high-temperature side heat transfer medium circuit 20 by the heat transfer medium flow path 30f. Therefore, the heat transfer medium that flows from the second low-temperature side heat exchanger 142 to the flow rate adjustment unit V30 via the heat transfer medium flow path 30c is branched into the heat transfer medium flow path 30d and the heat transfer medium flow path 30f, allowing it to flow to the high-temperature side heat transfer medium circuit 20 and the second low-temperature side heat exchanger 142. Thus, at least a portion of the heat transfer medium cooled in the second low-temperature side heat exchanger 142 can flow from the low-temperature side heat transfer medium circuit 30 to the high-temperature side heat transfer medium circuit 20.

[0033] The flow rate adjustment unit V30 adjusts the flow rate of the heat transfer medium flowing into the second low-temperature heat exchanger 142 and the flow rate of the heat transfer medium flowing into the high-temperature heat transfer medium circuit 20. In other words, the flow rate adjustment unit V30 adjusts the amount of heat transfer medium flowing from the low-temperature heat transfer medium circuit 30 to the high-temperature heat transfer medium circuit 20 downstream of the second low-temperature heat exchanger 142.

[0034] <HVAC Unit> The heater core 21 of the high-temperature side heat transfer medium circuit 20 and the cooler core 31 of the low-temperature side heat transfer medium circuit 30 are housed within the case 110 of the HVAC unit 100. The case 110 forms the outer shell of the HVAC unit 100 and also forms an air passage 120 inside.

[0035] Furthermore, the HVAC unit 100 has an intake unit 130. The intake unit 130 switches the air introduced into the case 110 between outside air (outside air intake) and inside air (inside air circulation) by closing either the outside air intake port for introducing outside air or the inside air intake port for introducing inside air. In addition, the HVAC unit 100 has a blower 140 installed adjacent to the intake unit 130 so that the air introduced into the case 110 is introduced into the air passage 120.

[0036] A cooler core 31 is located upstream of the airflow passage 120, and a heater core 21 is located downstream of the cooler core 31. Therefore, the air introduced into the case 110 passes through the cooler core 31 and then through the heater core 21. Alternatively, a bypass passage for the heater core 21 may be provided, and an air mix damper may be used to adjust the ratio of air that passes through the cooler core 31 and bypasses the heater core 21 to air that passes through the cooler core 31 and then through the heater core 21.

[0037] <Control device 200> Figure 2 is an explanatory diagram showing a schematic example of the configuration of the control device 200 included in the thermal management system 1.

[0038] The control device 200 includes a processor 201, memory 202, storage 203, and interface 204. The processor 201 is, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit). The memory 202 is, for example, RAM (Random Access Memory). The storage 203 is a rewritable non-volatile memory such as an HDD (Hard Disk Drive), SSD (Solid State Drive), or flash memory. The storage 203 stores a system program including an OS (Operating System) and a control program including computer-readable code necessary for control calculations. The processor 201 performs various processes by reading the system program and the control program, loading them into memory 202, and executing them. The interface 204 controls communication between the control device 200 and the components of the thermal management system 1.

[0039] The control device 200 can selectively form one or more circuits through which the heat transfer medium circulates by controlling the operation of the heat management system 1 in accordance with the operation required of the vehicle (for example, air conditioning inside the vehicle).

[0040] Detection information is input to the control device 200 from various sensors included in the thermal management system 1. For example, it includes a blower temperature sensor 210 that detects the temperature of the air blown into the vehicle interior, an outside air temperature sensor 220 that detects the outside air temperature, a refrigerant temperature sensor 230 that detects the temperature of the refrigerant circulating in the refrigerant circuit 10, a refrigerant pressure sensor 240 that detects the pressure of the refrigerant circulating in the refrigerant circuit 10, a vehicle interior temperature sensor 250 that detects the temperature of the vehicle interior, a rotational speed detection sensor 260 that detects the rotational speed of the compressor 51, a high-temperature side heat medium temperature sensor 270 that detects the temperature of the heat medium circulating in the high-temperature side heat medium circuit 20, and a low-temperature side heat medium temperature sensor 280 that detects the temperature of the heat medium circulating in the low-temperature side heat medium circuit 30.

[0041] Based on the detection information from various sensors, the control device 200 controls the rotational speed of the compressor 11, the operations of the decompression devices 13a and 13b, the operations of the flow rate adjustment parts V20 and V30, the operations of the circulation pumps P20, P30, and P31, the operation of the blower 140, etc. Thereby, the water mixing heating mode described later can be executed.

[0042] [Operation of the Thermal Management System 1] The specific operation of the thermal management system 1 will be described.

[0043] When the outside air temperature is extremely low (for example, -20°C to -30°C), it is difficult to utilize the heat of the outside air, so outside air heat absorption heating becomes difficult. In this case, since there is no other heat absorption source, heat pump operation in the refrigerant circuit 10 becomes difficult. Therefore, it is necessary to execute a heating operation that does not rely on outside air heat absorption at extremely low temperatures.

[0044] For this reason, for example, it is conceivable to execute a heating operation using a heat exchange cycle called a hot gas cycle. In the hot gas cycle, the heat medium is heated by exchanging heat in the first low-temperature side heat exchanger 141 without exchanging heat in the high-temperature side heat exchanger 12. Then, the heating operation is executed by flowing the heat medium heated in the first low-temperature side heat exchanger 141 to the cooler core 31.

[0045] However, in a hot gas cycle, the refrigerant is depressurized upstream of the first low-temperature heat exchanger 141 in the refrigerant circuit 10, so the temperature of the heat transfer medium does not rise to the temperature required for heating operation (for example, around 30°C). For this reason, it is necessary to increase the rotational speed of the compressor 11 to increase the pressure and temperature of the refrigerant discharged by the compressor 11. However, raising the temperature of the heat transfer medium to the temperature required for heating operation (for example, around 60°C) would require increasing the rotational speed of the compressor 11 too much, leading to compressor failure. Therefore, in a hot gas cycle, there is a limitation on the outlet temperature of the air blown into the vehicle cabin.

[0046] To solve this problem, it is conceivable to perform heating operation using a heat exchange cycle called a hot gas bypass cycle. The hot gas bypass cycle uses a refrigerant circuit that has a bypass path in which a portion of the refrigerant discharged by the compressor 11 bypasses the high-temperature side heat exchanger 12 and flows to the upstream side of the compressor 11. In the hot gas bypass cycle, a portion of the refrigerant discharged by the compressor 11 flows through the bypass path, while the remaining refrigerant flows to the high-temperature side heat exchanger 12. Then, heating operation is performed by flowing the heat transfer medium heated in the high-temperature side heat exchanger 12 to the heater core 21.

[0047] However, in a hot gas bypass cycle, although the temperature of the heat transfer medium rises to the temperature required for heating operation (for example, around 60°C), the refrigerant circuit becomes larger due to the provision of a bypass path. In particular, when using a flammable refrigerant, it is necessary to make the refrigerant circuit compact to ensure safety. Furthermore, in a hot gas bypass cycle, the refrigerant circulates through the bypass path, which increases the amount of refrigerant circulated and requires high-load operation of the compressor 11.

[0048] Thus, neither the hot gas cycle nor the hot gas bypass cycle is suitable as an alternative means for outdoor air heat absorption heating. Therefore, in this embodiment, heating operation using the operation mode of the heat management system 1 called the water mixing heating mode can be executed as an alternative means for outdoor air heat absorption heating. In the water mixing heating mode, at least a part of the heat medium heated by the high-temperature side heat exchanger 12 flows from the high-temperature side heat medium circuit 20 to the low-temperature side heat medium circuit 30, and the heat of the heat medium flowing from the high-temperature side heat medium circuit 20 to the low-temperature side heat medium circuit 30 is absorbed by the refrigerant by the second low-temperature side heat exchanger 142. Therefore, by heating the heat medium circulating in the low-temperature side heat medium circuit 30 with the heat medium heated by the high-temperature side heat exchanger 12, it becomes possible to use the heat medium in the low-temperature side heat medium circuit 30 as a heat absorption source. Thus, even in a situation where the outdoor air is extremely low temperature and there is no heat absorption source, heat pump operation becomes possible, and it is possible to avoid the limitation of the blowing temperature by the hot gas cycle and the high-load operation by the hot gas bypass cycle.

[0049] 〈Execution of Water Mixing Heating Mode〉 The following describes the specific process when the control device 200 executes the water mixing heating mode with reference to FIG. 3. In FIG. 3, the temperature of the heat medium in the high-temperature side heat medium circuit 20 is abbreviated as the high-temperature side temperature, and the temperature of the heat medium in the low-temperature side heat medium circuit 30 is abbreviated as the low-temperature side temperature.

[0050] As shown in FIG. 3, the control device 200 determines whether a request for the water mixing heating mode has occurred (S1). The request for the water mixing heating mode occurs when the outdoor air temperature becomes extremely low and it is difficult to execute outdoor air heat absorption heating. The request for the water mixing heating mode can occur at the start of the heat management system 1 (at the start of operation) or during the execution of heating operation other than the water mixing heating mode.

[0051] If the control device 200 determines that the request for the water mixing heating mode has not occurred (S1: NO), the process ends.

[0052] If the control device 200 determines that the request for the water mixing heating mode has occurred (S1: YES), it determines whether the temperature of the heat medium in the low-temperature side heat medium circuit 30 is higher than the temperature of the heat medium during normal control of the water mixing heating mode in step S8 (S2).

[0053] If the temperature of the heat transfer medium in the low-temperature heat transfer medium circuit 30 is lower than the temperature of the heat transfer medium during normal control of the water-mixed heating mode in step S8 (S2: NO), the control device 200 executes the first stage of startup control for the water-mixed heating mode (S3). The first stage of startup control for the water-mixed heating mode heats the heat transfer medium in the low-temperature heat transfer medium circuit 30.

[0054] The first stage of the startup control for the water mixing heating mode functions as a low-temperature side heat exchange heating mode, in which the heat transfer medium circulating in the low-temperature side heat transfer medium circuit 30 is heated by the second low-temperature side heat exchanger 142.

[0055] If the heat transfer medium in the low-temperature heat transfer medium circuit 30 is not sufficiently warmed, it will be difficult for the refrigerant to absorb heat from the heat transfer medium in the second low-temperature heat exchanger 142, which may prevent the refrigeration cycle from functioning. For the refrigeration cycle to function, for example, the temperature of the heat transfer medium in the low-temperature heat transfer medium circuit 30 must be 0°C or higher, and the temperature of the heat transfer medium in the high-temperature heat transfer medium circuit 20 must be equal to the target discharge temperature. Therefore, by executing the first stage of the startup control, the temperature of the heat transfer medium circulating in the low-temperature heat transfer medium circuit 30 is increased by first heating the heat transfer medium in the second low-temperature heat exchanger 142 using a hot gas cycle that does not perform heat exchange in the high-temperature heat exchanger 12 but instead performs heat exchange in the second low-temperature heat exchanger 142. In this case, it is preferable that the temperature of the heat transfer medium passing through the inlet of the heat transfer medium passage 142b of the second low-temperature heat exchanger 142 is higher than the temperature in the normal control after startup of the water-mix heating mode (for example, 10°C or higher).

[0056] In the first stage of the startup control of the water mixing heating mode in step S3, the following controls (1) to (5) are performed.

[0057] (1) Rotation speed of compressor 11: Controls the temperature of the heat medium at the inlet or outlet of the heat medium passage 142b of the second low-temperature heat exchanger 142 to reach the target temperature (e.g., 10°C). (2) Pressure reducing device: Fixes the opening of the pressure reducing device 13b to an arbitrary opening (e.g., fully open). Closes the pressure reducing device 13a completely. (3) Flow rate adjustment units V20, V30: Controls the flow rate so that there is no inflow or outflow of the heat medium between the high-temperature heat medium circuit 20 and the low-temperature heat medium circuit 30. (4) Circulation pump: Controls the circulation pump P31 so that the flow rate of the heat medium passing through the second low-temperature heat exchanger 142 is constant (e.g., 10 L / min). Stops the operation of circulation pumps P20 and P30. (5) Blower 140: Stops.

[0058] Next, the control device 200 performs the second stage of startup control for the water-mixed heating mode (S4). The second stage of startup control for the water-mixed heating mode heats the heat transfer medium in the high-temperature side heat transfer medium circuit 20.

[0059] Furthermore, when the temperature of the heat medium at the inlet or outlet of the heat medium passage 142b of the second low-temperature side heat exchanger 142 reaches or exceeds the target temperature, the system transitions from the first stage to the second stage of the startup control. In other words, when the temperature of the heat medium circulating in the low-temperature side heat medium circuit 30 reaches or exceeds a predetermined threshold target temperature, the system switches to the second stage of the startup control, which is the high-temperature side heat medium absorption mode. Thus, the heat medium circulating in the low-temperature side heat medium circuit 30 can store the heat source necessary for heat pump operation.

[0060] The second stage of the startup control for the water-mixed heating mode functions as a high-temperature heat transfer medium heat absorption mode, in which at least a portion of the heat transfer medium heated in the high-temperature heat exchanger 12 is transferred from the high-temperature heat transfer medium circuit 20 to the low-temperature heat transfer medium circuit 30, and the heat from the heat transfer medium that has flowed from the high-temperature heat transfer medium circuit 20 to the low-temperature heat transfer medium circuit 30 is absorbed by the refrigerant in the second low-temperature heat exchanger 142.

[0061] In the second stage of the startup control of the water mixing heating mode in step S4, the following controls (1) to (5) are performed.

[0062] (1) Rotation speed of compressor 11: Controlled so that the temperature of the heat medium in the high-temperature side heat medium circuit 20 (for example, the temperature of the heat medium passing through the outlet of the heat medium passage 12b of the high-temperature side heat exchanger 12) is equal to (i.e., the same or approximately the same as) the target blow-off temperature. (2) Pressure reducing device: The opening of the pressure reducing device 13b is fixed to an arbitrary opening (for example, fully open). The pressure reducing device 13a is fully closed. (3) Flow rate adjustment units V20, V30: Control the inflow and outflow of the heat medium in the high-temperature side heat medium circuit 20 and the low-temperature side heat medium circuit 30 so that the temperature of the heat medium in the low-temperature side heat medium circuit 30 (for example, the temperature of the heat medium passing through the inlet of the heat medium passage 141b of the first low-temperature side heat exchanger 141) is the target temperature (for example, 0°C). (4) Circulation pumps: Circulation pumps P20 and P31 are controlled so that the flow rate of the heat transfer medium passing through the high-temperature heat exchanger 12 and the second low-temperature heat exchanger 142 remains constant (for example, 10 L / min). The operation of circulation pump P30 is stopped. (5) Blower 140: Stops.

[0063] In the control described in (3) above, the control device 200 controls the opening of the flow rate adjustment unit V20 so that the amount of heat transfer medium flowing from the high-temperature heat transfer medium circuit 20 to the low-temperature heat transfer medium circuit 30 increases according to the temperature of the heat transfer medium circulating in the low-temperature heat transfer medium circuit 30. This makes it possible to increase the amount of heat stored in the heat transfer medium circulating in the low-temperature heat transfer medium circuit 30, thereby extending the period during which the heat pump can be operated.

[0064] Furthermore, in the control described in (3) above, the control device 200 controls the opening of the flow rate adjustment unit V30 according to the flow rate of the heat transfer medium flowing in from the high-temperature side heat transfer medium circuit 20, thereby adjusting the flow rate of the heat transfer medium flowing to the second low-temperature side heat exchanger 142 and the flow rate of the heat transfer medium flowing to the high-temperature side heat transfer medium circuit 20. In this way, by having the flow rate adjustment unit V20 and the flow rate adjustment unit V30 work together, the amount of heat transfer medium circulating in the high-temperature side heat transfer medium circuit 20 and the low-temperature side heat transfer medium circuit 30 can be kept constant.

[0065] Furthermore, since the temperature of the heat transfer medium in the low-temperature heat transfer medium circuit 30 is increased in the first stage, the amount of heat transfer medium entering and leaving the circuit does not increase rapidly.

[0066] Next, the control device 200 determines whether the temperature of the heat transfer medium in the low-temperature heat transfer medium circuit 30 is equal to or above the target temperature (S5). If the temperature of the heat transfer medium in the low-temperature heat transfer medium circuit 30 is not equal to or above the target temperature (S5: NO), the control device 200 returns to step S3. In other words, it returns to step S3 if the heat transfer medium in the low-temperature heat transfer medium circuit 30 has cooled down.

[0067] If the temperature of the heat transfer medium in the low-temperature heat transfer medium circuit 30 is equal to or above the target temperature (S5: YES), the control device 200 determines whether the temperature of the heat transfer medium in the high-temperature heat transfer medium circuit 20 is equal to the target discharge temperature (S6). The target discharge temperature is calculated based on, for example, the in-cabin set temperature, which is the temperature set by the occupants, the actual temperature inside the vehicle, the outside temperature, the amount of sunlight, etc.

[0068] If the temperature of the heat transfer medium in the high-temperature heat transfer medium circuit 20 is not equal to the target discharge temperature (S6: NO), the control device 200 returns to step S4.

[0069] The control device 200 performs normal control of the water-mixed heating mode (S8) if the temperature of the heat transfer medium in the high-temperature side heat transfer medium circuit 20 is equal to the target discharge temperature (S6: YES). Normal control of the water-mixed heating mode performs heating operation by blowing air heated by the heater core 21 into the vehicle cabin.

[0070] The normal control of the water-mixed heating mode is a high-temperature heat transfer medium heat absorption mode in which at least a portion of the heat transfer medium heated in the high-temperature heat exchanger 12 is passed from the high-temperature heat transfer medium circuit 20 to the low-temperature heat transfer medium circuit 30, and the heat from the heat transfer medium that has passed from the high-temperature heat transfer medium circuit 20 to the low-temperature heat transfer medium circuit 30 is absorbed by the refrigerant in the second low-temperature heat exchanger 142.

[0071] In the normal control of the water mixing heating mode in step S8, the following controls (1) to (5) are performed.

[0072] (1) Rotation speed of compressor 11: Controls the air blown into the vehicle cabin to reach the target blown temperature (e.g., 60°C). (2) Pressure reducing device: Fixes the opening of pressure reducing device 13b to an arbitrary opening (e.g., fully open). Pressure reducing device 13a is fully closed. (3) Flow rate adjustment units V20, V30: Controls the inflow and outflow of heat transfer medium in the high-temperature side heat transfer medium circuit 20 and the low-temperature side heat transfer medium circuit 30 so that the temperature of the heat transfer medium in the low-temperature side heat transfer medium circuit 30 (e.g., the temperature of the heat transfer medium passing through the inlet of the heat transfer medium passage 142b of the second low-temperature side heat exchanger 142) reaches the target temperature (e.g., 0°C). (4) Circulation pump: Controls the circulation pump P20 and circulation pump P31 so that the flow rate of the heat transfer medium passing through the high-temperature side heat exchanger 12 and the second low-temperature side heat exchanger 142 is constant (e.g., 10 L / min). The operation of circulation pump P30 is stopped. (5) Blower 140: The airflow rate is controlled to be below the target airflow rate and below the upper limit of the airflow rate. The upper limit is determined according to the temperature of the heat transfer medium in the high-temperature heat transfer medium circuit 20. When the temperature of the heat transfer medium in the high-temperature heat transfer medium circuit 20 decreases, the upper limit of the airflow rate decreases.

[0073] In the control described in (3) above, the control device 200 controls the opening of the flow rate adjustment unit V20 so that the amount of heat transfer medium flowing from the high-temperature heat transfer medium circuit 20 to the low-temperature heat transfer medium circuit 30 increases according to the temperature of the heat transfer medium circulating in the low-temperature heat transfer medium circuit 30. This makes it possible to increase the amount of heat stored in the heat transfer medium circulating in the low-temperature heat transfer medium circuit 30, thereby extending the period during which the heat pump can be operated.

[0074] Furthermore, in the control described in (3) above, the control device 200 controls the opening of the flow rate adjustment unit V30 according to the flow rate of the heat transfer medium flowing in from the high-temperature side heat transfer medium circuit 20, thereby adjusting the flow rate of the heat transfer medium flowing to the second low-temperature side heat exchanger 142 and the flow rate of the heat transfer medium flowing to the high-temperature side heat transfer medium circuit 20. In this way, by having the flow rate adjustment unit V20 and the flow rate adjustment unit V30 work together, the amount of heat transfer medium circulating in the high-temperature side heat transfer medium circuit 20 and the low-temperature side heat transfer medium circuit 30 can be kept constant.

[0075] When executing the control described in (3) above, the flow rate adjustment unit V20 adjusts the flow rate of the heat transfer medium flowing to the heater core 21 and the flow rate of the heat transfer medium flowing to the low-temperature side heat transfer medium circuit 30. By flowing the heat transfer medium into the low-temperature side heat transfer medium circuit 30, the amount of heat absorbed in the second low-temperature side heat exchanger 142 from the amount of heat released to the heat transfer medium by the high-temperature side heat exchanger 12 is moved to the low-temperature side heat transfer medium circuit 30 and absorbed in the second low-temperature side heat exchanger 142. The amount of heat absorbed in the second low-temperature side heat exchanger 142 is then used for heat release in the high-temperature side heat exchanger 12. Therefore, by generating the amount of heat by the compressor 11 obtained by subtracting the amount of heat absorbed in the second low-temperature side heat exchanger 142 from the amount of heat released to the heat transfer medium by the high-temperature side heat exchanger 12, the amount of heat to be released in the heater core 21 can be generated. As a result, in this embodiment, it becomes possible to perform heating operation with the amount of heat generated by the power of the compressor 11.

[0076] Furthermore, if the control device 200 determines in step S2 that the temperature of the heat transfer medium in the low-temperature heat transfer medium circuit 30 is higher than the temperature of the heat transfer medium during normal control in step S8 (S2: YES), it determines whether the temperature of the heat transfer medium in the high-temperature heat transfer medium circuit 20 is equivalent to the target discharge temperature (S7).

[0077] If the temperature of the heat transfer medium in the high-temperature heat transfer medium circuit 20 is not equal to the target discharge temperature (S7: NO), the control device 200 returns to step S4.

[0078] If the temperature of the heat transfer medium in the high-temperature heat transfer medium circuit 20 is equal to the target discharge temperature (S7: YES), the control device 200 performs normal control of the water-mixed heating mode (S8).

[0079] As described above, in this embodiment, after starting the first stage of startup control as the low-temperature side heat exchange heating mode, the system switches from the first stage of startup control as the low-temperature side heat exchange heating mode to the second stage of startup control as the high-temperature side heat transfer medium heat absorption mode and then to normal control to start the blower 140. Therefore, even when the outside air is extremely cold and there are no other heat absorption sources in the initial stages of startup, the heat pump can be operated by heating the heat transfer medium in the low-temperature side heat transfer medium circuit 30 and storing heat.

[0080] In this embodiment, an example was given in which the heat transfer medium in the low-temperature heat transfer medium circuit 30 is heated by flowing at least a portion of the heat transfer medium heated in the high-temperature heat exchanger 12 from the high-temperature heat transfer medium circuit 20 to the low-temperature heat transfer medium circuit 30. However, the heat transfer medium in the low-temperature heat transfer medium circuit 30 may also be heated by using other heating means in combination, such as exhaust heat from a motor or battery, or heating of the heat transfer medium by a heat transfer medium heating device.

[0081] [Effects of this embodiment] (1) A refrigerant circuit 10 having a high-temperature side heat exchanger 12 as a condenser and a second low-temperature side heat exchanger 142 as an evaporator; a high-temperature side heat transfer medium circuit 20 through which a heat transfer medium that exchanges heat with the refrigerant in the high-temperature side heat exchanger 12 circulates; and a low-temperature side heat transfer medium circuit 30 through which a heat transfer medium that exchanges heat with the refrigerant in the second low-temperature side heat exchanger 142 circulates, wherein at least a portion of the heat transfer medium heated in the high-temperature side heat exchanger 12 flows from the high-temperature side heat transfer medium circuit 20 to the low-temperature side heat transfer medium circuit 30, and the heat of the heat transfer medium that has flowed from the high-temperature side heat transfer medium circuit 20 to the low-temperature side heat transfer medium circuit 30 is absorbed by the refrigerant in the second low-temperature side heat exchanger 142. Therefore, by using the heat transfer medium heated in the high-temperature heat exchanger 12 to heat the heat transfer medium circulating in the low-temperature heat transfer medium circuit 30, it becomes possible to use the heat transfer medium in the low-temperature heat transfer medium circuit 30 as a heat absorption source. This allows the heat pump to operate even when the outside air is extremely cold and there is no heat absorption source, thus avoiding limitations on the discharge temperature due to the execution of the hot gas cycle and high-load operation due to the execution of the hot gas bypass cycle.

[0082] (2) The system includes a flow rate adjustment unit V20 located downstream of the high-temperature heat exchanger 12, and heat transfer fluid passages 20b and 20e that allow the heat transfer fluid that has flowed from the high-temperature heat exchanger 12 to the flow rate adjustment unit V20 to flow to the low-temperature heat transfer fluid circuit 30 and the heater core 21. The flow rate adjustment unit V20 adjusts the flow rate of the heat transfer fluid flowing to the heater core 21 and the flow rate of the heat transfer fluid flowing to the low-temperature heat transfer fluid circuit. As a result, the amount of heat released by the refrigerant in the high-temperature heat exchanger 12 can be used as the amount of heat absorbed by the refrigerant in the second low-temperature heat exchanger 142, so that the amount of heat used to power the compressor 11 can be used for heating operation.

[0083] (3) A thermal management system 1 comprising: a refrigerant circuit 10 having a high-temperature side heat exchanger 12 as a condenser and a second low-temperature side heat exchanger 142 as an evaporator; a high-temperature side heat transfer medium circuit 20 through which a heat transfer medium that exchanges heat with the refrigerant in the high-temperature side heat exchanger 12 circulates; and a low-temperature side heat transfer medium circuit 30 through which a heat transfer medium that exchanges heat with the refrigerant in the second low-temperature side heat exchanger 142 circulates, wherein the first stage of startup control of a water mixed heating mode is a low-temperature side heat exchange heating mode in which the heat transfer medium circulating in the low-temperature side heat transfer medium circuit 30 is heated in the second low-temperature side heat exchanger 142, The system allows for the execution of both the first stage of startup control and normal control of the water-mixed heating mode, which is a high-temperature heat transfer medium heat absorption mode, in which at least a portion of the heat transfer medium heated in the high-temperature heat exchanger 12 is flowed from the high-temperature heat transfer medium circuit 20 to the low-temperature heat transfer medium circuit 30, and the heat from the heat transfer medium that has flowed from the high-temperature heat transfer medium circuit 20 to the low-temperature heat transfer medium circuit 30 is absorbed by the refrigerant in the second low-temperature heat exchanger 142. After starting the low-temperature heat exchange heating mode, the system switches from the low-temperature heat exchange heating mode to the high-temperature heat transfer medium heat absorption mode and starts the blower 140. Therefore, even when the outside air is extremely cold and there are no other heat absorption sources in the initial stages of startup, the heat pump can be operated by heating and storing heat in the heat transfer medium of the low-temperature heat transfer medium circuit 30.

[0084] (4) When the temperature of the heat medium circulating in the low-temperature heat medium circuit 30 reaches a predetermined threshold target temperature or higher, the system switches to the high-temperature heat medium absorption mode. Thus, the heat medium circulating in the low-temperature heat medium circuit 30 can store the heat source necessary for heat pump operation.

[0085] (5) The high-temperature side heat transfer medium circuit 20 is equipped with a flow rate adjustment unit V20 that adjusts the amount of heat transfer medium flowing from the high-temperature side heat transfer medium circuit 20 to the low-temperature side heat transfer medium circuit 30 downstream of the high-temperature side heat exchanger 12. The flow rate adjustment unit V20 is controlled so that the amount of heat transfer medium flowing from the high-temperature side heat transfer medium circuit 20 to the low-temperature side heat transfer medium circuit 30 increases according to the temperature of the heat transfer medium circulating in the low-temperature side heat transfer medium circuit 30. As a result, it becomes possible to increase the amount of heat stored in the heat transfer medium circulating in the low-temperature side heat transfer medium circuit 30, thereby extending the period during which the heat pump can be operated.

[0086] Although the present invention has been described above with reference to preferred embodiments, it goes without saying that the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the present invention.

[0087] 1: Thermal management system 10: Refrigerant circuit 12: High-temperature heat exchanger 20: High-temperature heat transfer medium circuit 30: Low-temperature heat transfer medium circuit 21: Heater core 31: Cooler core 141: First low-temperature heat exchanger 142: Second low-temperature heat exchanger V20, V30: Flow rate adjustment unit P20, P30, P31: Circulation pump 200: Control device

Claims

1. A thermal management system comprising: a refrigerant circuit having a condenser and an evaporator; a high-temperature side heat transfer medium circuit through which a heat transfer medium that exchanges heat with the refrigerant in the condenser circulates; and a low-temperature side heat transfer medium circuit through which a heat transfer medium that exchanges heat with the refrigerant in the evaporator circulates, characterized in that at least a portion of the heat transfer medium heated in the condenser is flowed from the high-temperature side heat transfer medium circuit to the low-temperature side heat transfer medium circuit, and the heat of the heat transfer medium that has flowed from the high-temperature side heat transfer medium circuit to the low-temperature side heat transfer medium circuit is absorbed by the refrigerant in the evaporator.

2. The thermal management system according to claim 1, comprising a flow rate adjustment unit located downstream of the condenser, and a heat transfer medium flow path that flows the heat transfer medium that has flowed from the condenser to the flow rate adjustment unit to the low-temperature side heat transfer medium circuit and the heater core, wherein the flow rate adjustment unit adjusts the flow rate of the heat transfer medium flowing to the heater core and the flow rate of the heat transfer medium flowing to the low-temperature side heat transfer medium circuit.

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