Heat management system

Abstract

[Problem] To provide a heat management system with which a hot gas heating operation can be stabilized and in which the number of components can be reduced. [Solution] This heat management system 1 comprises a refrigerant circuit 10 that includes a compressor 11, a high temperature-side heat exchanger 12, a first low temperature-side heat exchanger 14 for cooling a heat medium, a second low temperature-side heat exchanger 16 disposed in parallel with the first low temperature-side heat exchanger 14 and for cooling the heat medium, and a pressure reducing device 13a disposed in a path on the upstream side of the first low temperature-side heat exchanger 14, wherein the refrigerant circuit 10 comprises: a refrigerant flow path 10b that is a bypass path that bypasses the high temperature-side heat exchanger 12 and merges with a path on the downstream side of a branch part a2 and on the upstream side of the pressure reducing device 13a the branch part a2 being between a refrigerant flow path 10j, which is the path through which the refrigerant flows to the first low temperature-side heat exchanger 14, and a refrigerant flow path 10h, which is the path through which the refrigerant flows to the second low temperature-side heat exchanger 16.

Description

Thermal Management System

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

[0002] There are known techniques for improving heating performance in air conditioning. For example, Patent Document 1 discloses a refrigerant circuit in which high-temperature gas discharged from a compressor bypasses an external heat exchanger, thereby improving heating performance.

[0003] International Publication No. 2023 / 037897

[0004] An object of the present invention is to provide a heat management system that can stabilize hot gas heating operation and reduce the number of parts.

[0005] According to one aspect of the present invention, a thermal management system is provided with a refrigerant circuit having a compressor, a condenser that heats a heat medium, a first evaporator that cools the heat medium, a second evaporator that is arranged in parallel with the first evaporator and cools the heat medium, and a pressure reducing device that is arranged upstream of the first evaporator, and the refrigerant circuit is provided with a bypass path that bypasses the condenser and joins a path downstream of the branch point between the first evaporator and the second evaporator and a path upstream of the pressure reducing device.

[0006] According to the present invention, a heat management system can be provided that can stabilize hot gas heating operation and reduce the number of parts.

[0007] FIG. 1 is a circuit diagram showing an example of the configuration of a refrigerant circuit provided in a thermal management system.

[0008] [System Configuration] <System Overview> Fig. 1 is an explanatory diagram showing an outline of an example configuration of a thermal management system 1 according to this embodiment. The thermal management system 1 is mounted on 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 electric vehicle (PHEV: Plug-in Hybrid Electric Vehicle), or a fuel cell electric vehicle (FCEV: Fuel Cell Electric Vehicle).

[0009] The thermal management system 1 includes a refrigerant circuit 10 configured to circulate a refrigerant. The refrigerant may be, but is not limited to, a hydrofluoroolefin, for example. The thermal management system 1 also includes a heat medium circuit (not shown) through which a heat medium fluid, such as a coolant liquid, circulates, and a control device (not shown) that controls the operation of the refrigerant circuit 10 and the heat medium circuit.

[0010] <Refrigerant Circuit> The refrigerant circuit 10 is configured to function as a heat pump that circulates refrigerant and repeats compression, condensation, expansion, and evaporation.

[0011] The refrigerant circuit 10 includes a compressor 11, a high-temperature side heat exchanger 12 which is a condenser, pressure reducing devices 13a, 13b, a first low-temperature side heat exchanger 14 which is a first evaporator, and a second low-temperature side heat exchanger 16 which is a second evaporator.

[0012] The compressor 11 compresses the gaseous refrigerant to a high temperature and high pressure, and then discharges the compressed refrigerant.

[0013] 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, for example, pushed by a circulation pump P20 installed in the heat medium circuit and passing through a heater core of the heat medium circuit, passes. The high-temperature side heat exchanger 12 condenses the gaseous refrigerant compressed by the compressor 11 and releases heat, thereby heating the heat medium passing through the heater core. This allows the vehicle interior to be heated.

[0014] The pressure reducing devices 13a and 13b are, for example, expansion valves, which expand the liquid refrigerant to a low pressure.

[0015] The first low-temperature side heat exchanger 14 includes a refrigerant passage 14a through which the refrigerant circulating in the refrigerant circuit 10 passes, and a heat medium passage 14b through which the heat medium, which is pushed out by, for example, a circulation pump P40 installed in the heat medium circuit and passes through a battery temperature adjustment unit that adjusts the temperature of the battery, passes. The first low-temperature side heat exchanger 14 cools the heat medium passing through the battery temperature adjustment unit by evaporating and absorbing heat from the liquid refrigerant that has been kept at a low temperature and pressure. This allows the temperature of the battery to be adjusted.

[0016] The second low-temperature side heat exchanger 16 is arranged in parallel with the first low-temperature side heat exchanger 14. The second low-temperature side heat exchanger 16 includes a refrigerant passage 16a through which the refrigerant circulating in the refrigerant circuit 10 passes, and a heat medium passage 16b through which, for example, a heat medium pushed out by a circulation pump P30 installed in the heat medium circuit passes and through which the heat medium passing through the cooler core passes. The second low-temperature side heat exchanger 16 cools the heat medium passing through the cooler core by evaporating and absorbing heat from a low-temperature, low-pressure liquid refrigerant. This allows the vehicle interior to be cooled.

[0017] The elements of the refrigerant circuit 10 are connected by refrigerant flow paths 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h, 10i, and 10j.

[0018] That is, the discharge side of the compressor 11 is connected to the inlet of a refrigerant passage 14a of the first low-temperature side heat exchanger 14 via a refrigerant passage 10a, a branch point a1, a refrigerant passage 10b, a junction point b1, and a downstream refrigerant passage 10c connected thereto. A two-way valve 17, which is a passage opening / closing valve, is installed on the refrigerant passage 10b. A pressure reducing device 13a is installed on the refrigerant passage 10c. That is, the pressure reducing device 13a is installed upstream of the first low-temperature side heat exchanger 14. The outlet of the refrigerant passage 14a of the first low-temperature side heat exchanger 14 is connected to the suction side of the compressor 11 via a refrigerant passage 10d connected thereto, a junction point b2, and a downstream refrigerant passage 10e. An accumulator 15 is installed on the refrigerant passage 10e.

[0019] The discharge side of the compressor 11 is connected to the inlet of a refrigerant passage 12a of the high-temperature side heat exchanger 12 via a refrigerant passage 10a connected thereto, a branch point a1, and a downstream refrigerant passage 10f. The outlet of the refrigerant passage 12a of the high-temperature side heat exchanger 12 is connected to the inlet of a refrigerant passage 16a of the second low-temperature side heat exchanger 16 via a refrigerant passage 10g connected thereto, a branch point a2, and a downstream refrigerant passage 10h. A pressure reducing device 13b is installed on the refrigerant passage 10h. That is, the pressure reducing device 13b is installed upstream of the second low-temperature side heat exchanger 16. The outlet of the refrigerant passage 16a of the second low-temperature side heat exchanger 16 is connected to the suction side of the compressor 11 via a refrigerant passage 10i connected thereto, a junction b2, and a downstream refrigerant passage 10e.

[0020] The outlet of the refrigerant passage 12a of the high-temperature side heat exchanger 12 is connected to the inlet of the refrigerant passage 14a of the first low-temperature side heat exchanger 14 via a refrigerant passage 10g, a branch point a2, a refrigerant passage 10j, a junction point b1, and a downstream refrigerant passage 10c. A check valve 18 is installed in the refrigerant passage 10j to prevent the refrigerant from flowing toward the branch point a2. That is, the check valve 18 is installed downstream of the branch point a2 and upstream of the junction point b1 of the refrigerant passage 10g.

[0021] By configuring the refrigerant flow path as described above, the refrigerant flow path 10b functions as a bypass route that bypasses the high-temperature side heat exchanger 12 and merges with the junction b1 downstream of the branching point a2 of the refrigerant flow path 10j through which the refrigerant flows to the first low-temperature side heat exchanger 14 and the refrigerant flow path 10h through which the refrigerant flows to the second low-temperature side heat exchanger 16, and upstream of the pressure reducing device 13a.

[0022] [System Operation] Next, a specific operation of the refrigerant circuit 10 included in the thermal management system 1 of this embodiment will be described.

[0023] <Execution of Hot Gas Heating Operation> FIG. 1 shows the state of the refrigerant circuit 10 when hot gas heating is performed when the outside air temperature is extremely low (for example, −20° C. to −30° C.).

[0024] When the hot gas heating operation is performed, the pressure reducing devices 13a and 13b are opened and the two-way valve 17 is opened.

[0025] As a result, the refrigerant discharged from the compressor 11 flows into the refrigerant flow paths 10a and 10f and passes through the refrigerant passage 12a of the high-temperature side heat exchanger 12. On the other hand, the heat medium that passes through the heater core in the heat medium circuit passes through the heat medium passage 12b. Then, the heat medium that absorbs heat in the high-temperature side heat exchanger 12 flows into the heater core, thereby heating the vehicle interior.

[0026] The refrigerant that passes through the refrigerant passage 12a of the high-temperature side heat exchanger 12 flows into the refrigerant flow paths 10g and 10h. As a result, the refrigerant that is reduced to a low temperature and low pressure by the pressure reducing device 13b passes through the refrigerant passage 16a of the second low-temperature side heat exchanger 16. When hot gas heating operation is performed, the heat medium that passes through the heat medium passage 16b of the second low-temperature side heat exchanger 16 does not circulate. Therefore, the refrigerant that passes through the refrigerant passage 16a of the second low-temperature side heat exchanger 16 flows into the refrigerant flow paths 10i and 10e without releasing heat and flows into the suction side of the compressor 11. In this way, during hot gas heating operation, the refrigerant flow paths 10a, 10f, 10g, 10h, 10i, and 10e form a circulation path through which the refrigerant discharged from the compressor 11 passes through the high-temperature side heat exchanger 12.

[0027] Furthermore, the refrigerant discharged from the compressor 11 flows through the refrigerant flow paths 10a, 10b, and 10c. As a result, the refrigerant reduced to a medium temperature and low pressure by the pressure reducing device 13a passes through the refrigerant passage 14a of the first low-temperature side heat exchanger 14. When hot gas heating operation is performed, the heat medium passing through the heat medium passage 14b of the first low-temperature side heat exchanger 14 does not circulate. Therefore, the refrigerant passing through the heat medium passage 14b of the first low-temperature side heat exchanger 14 flows into the refrigerant flow paths 10d and 10e without releasing heat and enters the suction side of the compressor 11. In this way, during hot gas heating operation, the refrigerant flow paths 10a, 10b, 10c, 10d, and 10e form a circulation path through which the refrigerant discharged from the compressor 11 bypasses the high-temperature side heat exchanger 12.

[0028] The refrigerant flowing through the bypass path does not actively exchange heat compared to the refrigerant that passes through the high-temperature side heat exchanger 12, and therefore has a higher temperature when it returns to the suction side of the compressor 11. As a result, in hot gas heating operation, the higher temperature of the refrigerant sucked into the compressor 11 makes it possible to increase the temperature of the refrigerant discharged from the compressor 11, thereby improving the heating capacity.

[0029] The refrigerant flowing through the bypass path during the hot gas heating operation can circulate a high-pressure refrigerant, thereby stabilizing the hot gas heating operation. In particular, in this embodiment, heat exchange with the heat medium is not performed between the first low-temperature side heat exchanger 14 and the second low-temperature side heat exchanger 16, so the hot gas heating operation can be more effectively stabilized.

[0030] In addition, when hot gas heating operation is performed, the pressure reducing device 13a used to reduce the pressure of the refrigerant flowing through the bypass route can also be used to reduce the pressure of the refrigerant flowing through the first low-temperature side heat exchanger 14, thereby reducing the number of parts.

[0031] In addition, by providing a check valve 18, it is possible to prevent the high-pressure refrigerant that has bypassed the high-temperature side heat exchanger 12 from flowing to the branch section a2 side instead of to the first low-temperature side heat exchanger 14 side, thereby preventing the refrigerant discharged from the compressor 11 from flowing back in the refrigerant circuit 10.

[0032] <Execution of Battery Cooling Operation> When performing an operation other than the hot gas heating operation, such as battery cooling operation, the refrigerant is circulated through the first low-temperature side heat exchanger 14 without circulating through the second low-temperature side heat exchanger 16. In this case, the pressure reducing device 13a is opened, the pressure reducing device 13b is fully closed, and the two-way valve 17 is closed. This forms a circulation path through the refrigerant flow paths 10a, 10f, 10g, 10j, 10c, 10d, and 10e. On the other hand, a circulation path that passes through the refrigerant flow paths 10a, 10f, 10g, 10h, 10i, and 10e and the bypass path through the refrigerant flow paths 10a, 10b, 10c, 10d, and 10e is not formed. As a result, the refrigerant that is cooled to a low pressure by the pressure reducing device 13a after being discharged from the compressor 11 passes through the refrigerant passage 14a of the first low-temperature side heat exchanger 14. On the other hand, the heat medium circulating in the battery temperature adjustment unit in the heat medium circuit passes through the heat medium passage 14b. Then, the heat medium that has dissipated heat in the first low-temperature side heat exchanger 14 flows into the battery temperature adjustment unit, thereby cooling the battery.

[0033] <Cooling Operation> When performing an operation other than the hot gas heating operation, such as cooling the passenger compartment, the refrigerant is not passed through the first low-temperature side heat exchanger 14 but is passed through the second low-temperature side heat exchanger 16. In this case, the pressure reducing device 13a is fully closed, the pressure reducing device 13b is opened, and the two-way valve 17 is closed. This forms a circulation path using the refrigerant flow paths 10a, 10f, 10g, 10h, 10i, and 10e. On the other hand, a circulation path using the refrigerant flow paths 10a, 10f, 10g, 10j, 10c, 10d, and 10e and a bypass path using the refrigerant flow paths 10a, 10b, 10c, 10d, and 10e is not formed. As a result, the refrigerant discharged from the compressor 11 and cooled to a low pressure by the pressure reducing device 13b passes through the refrigerant passage 16a of the second low-temperature side heat exchanger 16. On the other hand, the heat medium circulating through the cooler core in the heat medium circuit passes through the heat medium passage 16b. Then, the heat medium that has dissipated heat in the second low-temperature side heat exchanger 16 flows into the cooler core, thereby cooling the vehicle interior.

[0034] <Performing Cooling Operation and Battery Cooling Operation> When performing an operation other than the hot gas heating operation, such as cooling the vehicle cabin and cooling the battery, the refrigerant flows through the first low-temperature side heat exchanger 14 and the second low-temperature side heat exchanger 16. In this case, the pressure reducing device 13a is opened, the pressure reducing device 13b is opened, and the two-way valve 17 is closed. This forms a circulation path including refrigerant flow paths 10a, 10f, 10g, 10j, 10c, 10d, and 10e, and a circulation path including refrigerant flow paths 10a, 10f, 10g, 10h, 10i, and 10e. On the other hand, a circulation path via the bypass path including refrigerant flow paths 10a, 10b, 10c, 10d, and 10e is not formed. As a result, the refrigerant discharged from the compressor 11 and cooled to a low pressure by the pressure reducing device 13a passes through the refrigerant passage 14a of the first low-temperature side heat exchanger 14. On the other hand, the heat medium that passes through the battery temperature adjustment unit in the heat medium circuit passes through the heat medium passage 14b. Then, the heat medium that has dissipated heat in the first low-temperature side heat exchanger 14 flows into the battery temperature adjustment unit, thereby cooling the battery. Also, the refrigerant that is cooled to a low temperature and pressure in the pressure reducing device 13b after being discharged from the compressor 11 passes through the refrigerant passage 16a of the second low-temperature side heat exchanger 16. On the other hand, the heat medium that passes through the cooler core in the heat medium circuit passes through the heat medium passage 16b. Then, the heat medium that has dissipated heat in the second low-temperature side heat exchanger 16 flows into the cooler core, thereby cooling the vehicle interior.

[0035] As described above, the refrigerant circuit 10 of this embodiment does not require a separate pressure reducing device for reducing the pressure of the refrigerant flowing through the bypass path, thereby reducing the manufacturing costs of the thermal management system 1. Furthermore, if a pressure reducing device is provided in the bypass path, there is a risk that the refrigerant will leak from the high-pressure side to the low-pressure side even if the pressure reducing device is fully closed, but by providing the two-way valve 17 in the bypass path, the refrigerant can be completely blocked, preventing a decrease in performance in operations other than hot gas operation.

[0036] Furthermore, if the check valve 18 is not provided, there is a risk that the refrigerant will not flow from the branch portion a1 to the high-temperature side heat exchanger 12 side, which has a high flow resistance, but by providing the check valve 18, the pressure in the circuit can be adjusted so that the refrigerant also flows from the branch portion a1 to the high-temperature side heat exchanger 12 side. Furthermore, when the two-way valve 17 is open, high-pressure refrigerant flows to the outlet side of the check valve 18, so providing the check valve 18 can prevent the refrigerant that has passed through the high-temperature side heat exchanger 12 from flowing into the first low-temperature side heat exchanger 14.

[0037] Furthermore, by providing the two-way valve 17, the refrigerant can be completely shut off, preventing a decrease in performance in operations other than the hot gas operation.

[0038] In this embodiment, an example has been given in which the first low-temperature side heat exchanger 14 exchanges heat with a heat medium passing through a battery temperature control unit, and the second low-temperature side heat exchanger 16 exchanges heat with a heat medium passing through a cooler core, but the temperature control target of the heat medium exchanged by the first low-temperature side heat exchanger 14 and the second low-temperature side heat exchanger 16 does not have to be limited to this embodiment.

[0039] [Effects of the Present Embodiment] (1) A thermal management system 1 includes a refrigerant circuit 10 having a compressor 11, a high-temperature side heat exchanger 12 as a condenser that heats a heat medium, a first low-temperature side heat exchanger 14 as a first evaporator that cools the heat medium, a second low-temperature side heat exchanger 16 arranged in parallel with the first low-temperature side heat exchanger 14 and serving as a second evaporator that cools the heat medium, and a pressure reducing device 13a arranged in a path upstream of the first low-temperature side heat exchanger 14, wherein the refrigerant circuit 10 includes a refrigerant flow path 10b that bypasses the high-temperature side heat exchanger 12 and is downstream of a branch point a2 between a refrigerant flow path 10j through which a refrigerant flows to the first low-temperature side heat exchanger 14 and a refrigerant flow path 10h through which a refrigerant flows to the second low-temperature side heat exchanger 16, and that joins the path upstream of the pressure reducing device 13a. Therefore, during hot gas heating operation, high-pressure refrigerant can be circulated by the refrigerant flowing through the bypass path, thereby stabilizing hot gas heating operation. In addition, when hot gas heating operation is performed, the pressure reducing device 13a used to reduce the pressure of the refrigerant flowing through the bypass route can also be used to reduce the pressure of the refrigerant flowing through the first low-temperature side heat exchanger 14, thereby reducing the number of parts.

[0040] (2) A check valve 18 is provided downstream of the branch a2 and upstream of the junction b1 of the bypass path to prevent the refrigerant from flowing toward the branch a2. This prevents the high-pressure refrigerant that bypasses the high-temperature side heat exchanger 12 from flowing toward the branch a2 without flowing toward the first low-temperature side heat exchanger 14, thereby preventing the refrigerant discharged from the compressor 11 from flowing back through the refrigerant circuit 10.

[0041] (3) The refrigerant flow path 10g is provided with a two-way valve 17 as a flow path opening / closing valve. By providing the two-way valve 17, the refrigerant can be completely shut off, preventing a decrease in performance in operations other than the hot gas operation.

[0042] The present invention has been described above by showing preferred embodiments, but it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

[0043] 1: Heat management system 10: Refrigerant circuit 13a, 13b: Pressure reducing device 17: Two-way valve 18: Check valve a1, a2: Branching section b1, b2: Confluence section

Claims

1. A thermal management system comprising a refrigerant circuit having a compressor, a condenser that heats a heat medium, a first evaporator that cools the heat medium, a second evaporator that is arranged in parallel with the first evaporator and cools the heat medium, and a pressure reducing device that is arranged in a path upstream of the first evaporator, wherein the refrigerant circuit has a bypass path that bypasses the condenser and is downstream of a branch point between the path through which the refrigerant flows to the first evaporator and the path through which the refrigerant flows to the second evaporator, and that joins the path upstream of the pressure reducing device.

2. A thermal management system as described in claim 1, characterized in that a check valve is provided in the route downstream of the branch and in the route upstream of the confluence of the bypass route to prevent refrigerant from flowing toward the branch.

3. The thermal management system according to claim 1, wherein a flow path opening / closing valve is provided in the bypass path.

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