JP7706432B2 - Circulating water circuit structure - Google Patents

Description

An embodiment of the present invention relates to a circuit structure for circulating water.

Conventionally, a circulating water circuit structure mounted on an electric vehicle such as a BEV (Battery Electric Vehicle) includes a heater circuit that heats water by a heater and circulates it to heat the vehicle interior under normal conditions, a coolant circuit for cooling the vehicle battery, etc., a four-way valve that connects the heater circuit and the coolant circuit and separates the heater circuit from the coolant circuit, and a reserve tank. When the vehicle environment is low, this type of circulating water circuit structure switches the heater circuit and the coolant circuit to a state where they are directly connected by the four-way valve in order to heat the battery.
In a hybrid electric vehicle (HEV), for example, water is heated by an engine and circulated within the vehicle. In a BEV, the vehicle battery and the like are cooled by a refrigerant instead of water flowing through a circuit. For example, in the invention of a temperature control system disclosed in Patent Document 1, independent cooling paths can be switched between an independent state and a connected state by a four-way valve. In the inventions disclosed in Patent Documents 2 and 3, for example, the flow of water in the circuit is controlled by a three-way valve, and the independent cooling paths are connected via a reserve tank.

JP 2014-218135 A JP 2017-106432 A Japanese Patent Application Publication No. 10-266856

When pouring water into the circuit structure, water is poured in through the upper water inlet of the reserve tank, so the outlet port of the reserve tank, where water first enters the circuit structure, is set at the bottom of the reserve tank, and water enters in the direction of water flow. The water flowing through the circuit structure returns to the inlet port set at the top of the reserve tank, along with the air in the circuit structure. Therefore, when pouring water, water does not enter the inlet port, and air is removed from the circuit structure by the water returning to the inlet port. However, to ensure water pouring, the water inlet side must be set at the top of the reserve tank, and the outlet side where water first enters must be set at the bottom of the reserve tank, which imposes mounting constraints.

In addition, if the heater circuit and the coolant circuit are separated, for example, the pressure in the coolant circuit without a reserve tank will increase, affecting the internal pressure strength of the battery, causing a breakdown. In addition, devices other than the battery must also be kept at an allowable internal pressure, and increased pressure can cause water leakage from hoses used in the circuit. Therefore, in the circuit structure for circulating water installed in electric vehicles, etc., there is a challenge to improve the efficiency of water injection and to be able to absorb pressure increases and decreases within the circuit.

The circuit structure of the circulating water in this embodiment for solving the above problem includes a cooling water circuit for cooling a specific component, a heater circuit in which a heater is disposed, a four-way valve for switching between a state in which the cooling water circuit and the heater circuit are directly connected and a state in which the cooling water circuit and the heater circuit are separated, and a reserve tank having an air reservoir and disposed in the cooling water circuit or the heater circuit, and the cooling water circuit and the heater circuit are connected to each other via a pressure relief path and the reserve tank, and the pressure relief path is connected to the air reservoir of the reserve tank.

The circulating water circuit structure of this embodiment allows air to be properly removed from the cooling water circuit and heater circuit via the pressure relief path to the reserve tank during water injection, improving water injection efficiency. In addition, when the heater circuit and the cooling water circuit are disconnected, the pressure increase or decrease that occurs can be absorbed by the reserve tank via the pressure relief path.

FIG. 1 is an explanatory diagram illustrating a circuit structure of circulating water, an inverter cooling circuit, and a heat pump system according to this embodiment that are mounted on an electric vehicle. FIG. 2 is an explanatory diagram for explaining the height difference between the heater circuit and the coolant circuit within the electric vehicle, and water injection into the circuit structure of the circulating water. FIG. 3 is an explanatory diagram illustrating the flow of heated water in the heater circuit and the flow of cooled water in the coolant circuit when the heater circuit and the coolant circuit are disconnected. FIG. 4 is an explanatory diagram illustrating the flow of water within the circulating water circuit structure in a state in which the heater circuit and the coolant circuit are directly connected.

The following describes an embodiment of the circulating water circuit structure 1 of the present embodiment with reference to the attached drawings. The circulating water circuit structure 1 of the embodiment is mounted on an electric vehicle 9 such as a BEV. The circulating water circuit structure 1 includes, for example, a coolant circuit 3 and a heater circuit 4. The coolant circuit 3 is also called a battery circuit.

The coolant circuit 3 is a circulation path connected by cooling piping 36, and includes, for example, an electric water pump 30 (hereinafter referred to as pump 30), a water temperature sensor 31 that measures the temperature of the water flowing through the coolant circuit 3, a battery 32, an electronic unit 33, a chiller 35, and a four-way valve 34, arranged in the above order. Note that in this embodiment, the specified component that is the target of cooling by the coolant circuit 3 is the battery 32, but the specified component is not limited to the battery 32. Furthermore, the configurations arranged in the coolant circuit 3 are not limited to the above configurations.

The battery 32 is composed of a battery pack and other electronic devices. The electronic unit 33 is a unit that integrates a current sensor that detects the charging and discharging current of the battery 32, as well as the functions of charging, power conversion, and power distribution. The pump 30 is disposed in the cooling pipe 36 between the four-way valve 34 and the battery 32. The pump 30 is a driving source that circulates the cooling water so that the cooling water cooled by the chiller 35 is supplied to the battery 32.

The four-way valve 34 is disposed in the cooling pipe 36 between the chiller 35 and the pump 30. The four-way valve 34 includes, for example, a disk valve 345 in a casing 340. The disk valve 345 can be rotated in the casing 340 by a pulse motor or the like. The rotation angle of the disk valve 345 from the origin position can be recognized by the number of drive pulses supplied to the pulse motor. The casing 340 of the four-way valve 34 is formed with a first port 341, a second port 342, a third port 343, and a fourth port 344, and the first port 341 and the second port 342 are each connected to the cooling pipe 36. In addition, the third port 343 and the fourth port 344 are each connected to the heater pipe 48 of the heater circuit 4.

In the state shown in FIG. 1, the four-way valve 34 communicates the first port 341 and the second port 342, and communicates the third port 343 and the fourth port 344, by using the horizontally oriented disk valve 345 (hereinafter referred to as the disk valve 345 in the disconnection mode), and disconnects the coolant circuit 3 and the heater circuit 4. That is, the four-way valve 34 makes the coolant circuit 3 and the heater circuit 4 independent of each other by using the disk valve 345 in the disconnection mode. When the disk valve 345 of the four-way valve 34 rotates from the horizontally oriented state to the vertically oriented state shown in FIG. 2, the first port 341 and the third port 343 are communicated, and the second port 342 and the fourth port 344 are communicated, and the coolant circuit 3 and the heater circuit 4 are directly connected. The vertically oriented disk valve 345 shown in FIG. 2 is hereinafter referred to as the disk valve 345 in the direct connection mode.

The heater circuit 4 is a circulation path connected by heater piping 48, and includes, for example, an electric water pump 40 (hereinafter referred to as pump 40), a water-cooled condenser 41 that functions as a radiator, a high-voltage water heater 42 (hereinafter referred to as heater 42), a water temperature sensor 43, a heater core 44 that is a heat exchanger that heats air with heated water to heat the vehicle interior, a water temperature sensor 45, a four-way valve 34, and a reserve tank 46, arranged in the above order. Note that the configurations arranged in the heater circuit 4 are not limited to the above configurations.

The pump 40 is provided in the heater pipe 48 between the reserve tank 46 and the water-cooled condenser 41, and is a driving source that circulates the heated water so that the water heated by the heater 42 is supplied to the heater core 44. The water-cooled condenser 41 operates when the temperature of the water flowing in the heater circuit 4 is lowered. The water temperature sensor 43 and the water temperature sensor 45, which are disposed before and after the heater core 44, measure the temperature of the water supplied to the heater core 44 or the temperature of the water that has passed through the heater core 44.

Figure 2 is an explanatory diagram specifically showing the height difference within the electric vehicle 9 of each of the above-mentioned components constituting the heater circuit 4 of the circulating water circuit structure 1 and each of the above-mentioned components constituting the coolant circuit 3. For convenience, in this specification, the Z-axis direction including the +Z direction and the -Z direction shown in Figure 2 is defined as the height direction of the electric vehicle 9, the +Z direction is defined as approximately the upward direction of the electric vehicle 9, and the height increases toward the +Z direction. Also, the -Z direction is defined as approximately the downward direction of the electric vehicle 9, and the height decreases toward the -Z direction. The coolant circuit 3 is disposed at a relatively lower position within the electric vehicle 9 than the heater circuit 4.

As shown in FIG. 2, the reserve tank 46 disposed in the heater circuit 4 is disposed, for example, at the uppermost position in the electric vehicle 9 among the heater circuit 4 and the coolant circuit 3. In other words, the reserve tank 46 is disposed at a higher position in the electric vehicle 9 than the water-cooled condenser 41, heater core 44, and heater 42, which are located at a relatively high position in the heater circuit 4, as well as the chiller 35 and electronic unit 33 of the coolant circuit 3.

The reserve tank 46 is, for example, a sealed reserve tank. The reserve tank 46 is made of, for example, a hard resin material, and includes a water inlet 461, a water outlet 462 that allows water to flow from the tank interior 460 to the heater piping 48, and a water inlet 463 that is used when water is poured into the tank interior 460 from outside the circuit structure 1 and that includes a pressurized cap or the like. When pouring water into the circulating water circuit structure 1 as shown in FIG. 2, the water inlet 461 allows the poured water to flow into the heater circuit 4.

In this embodiment, for example, the water inlet 461 and the water outlet 462 are formed in the bottom 464 of the reserve tank 46. The water inlet 461 is connected to the third port 343 of the four-way valve 34 via the heater piping 48. The water outlet 462 is connected to the pump 40 via the heater piping 48. The water inlet 463 is formed in, for example, the top wall 466 of the reserve tank 46.

The reserve tank 46 is set with a maximum allowable water level 467. The space above the maximum allowable water level 467 in the tank interior 460 becomes an air reservoir 468 for releasing the increased pressure in the heater circuit 4 and the coolant circuit 3. For example, when the heater circuit 4 and the coolant circuit 3 are independent, the increased pressure in the coolant circuit 3 can be released to the air reservoir 468 through the pressure release path 50. The maximum allowable water level 467 is determined, for example, by a mark (not shown) indicating the maximum allowable water level 467 preset on the side wall 465 of the reserve tank 46. Note that the maximum allowable water level 467 is not limited to the form determined by the mark (not shown) preset on the side wall 465, and may be determined by the internal volume of the reserve tank 46, etc. The water inlet 461 and the water outlet 462 are not limited to being formed on the bottom 464, but may be formed at a position lower than at least the maximum allowable water level 467 on, for example, the side wall 465 of the reserve tank 46.

The cooling water circuit 3 and the heater circuit 4 are connected to each other via the pressure relief path 50 and the reserve tank 46 shown in FIG. 2. One end 501 of the pressure relief path 50 is connected to the air reservoir 468 of the reserve tank 46. The pressure relief path 50 is made of a metal pipe or a rubber hose, and the one end 501 of the pressure relief path 50 is located higher in the height direction of the electric vehicle 9 than the other end 502 of the pressure relief path 50. The pressure relief path 50 also functions as an air bleed path for air present in the circuit structure 1 when water is poured in.

For example, a connection port 469 is formed at a location on the side wall 465 of the reserve tank 46 that is higher than the maximum allowable water level 467. One end 501 of the pressure relief path 50 is connected to the air reservoir 468 via the connection port 469.

The other end 502 of the pressure relief path 50 is connected to a higher location in the height direction of the electric vehicle 9 where the air in the cooling water circuit 3 is likely to escape when water is poured. Specifically, as shown in FIG. 2, the heater circuit 4 is located relatively higher in the height direction in the electric vehicle 9 than the cooling water circuit 3, but the chiller 35 of the cooling water circuit 3 is located higher in the height direction in the electric vehicle 9, similar to the water-cooled condenser 41 and heater core 44 of the heater circuit 4. The cooling pipe 36 connecting the chiller 35 and the first port 341 of the four-way valve 34 includes, for example, a high-position pipe 361 arranged at a high position in the electric vehicle 9, and a low-position pipe 362 connected to the high-position pipe 361, extending downward, and arranged at a low position in the height direction and connected to the four-way valve 34. The other end 502 of the pressure relief path 50 is connected to the high-position pipe 361.

In this embodiment, for example, the pipe diameter of the pressure relief path 50 is smaller than the pipe diameter of the cooling pipe 36 of the cooling water circuit 3 and the pipe diameter of the heater pipe 48 of the heater circuit 4.

As shown in FIG. 1, the electric vehicle 9 includes, in addition to the circuit structure 1 for circulating water, an inverter cooling circuit 2 and a heat pump system 7. The inverter cooling circuit 2, which is arranged, for example, on the more external side of the electric vehicle 9 than the coolant circuit 3, the heater circuit 4, and the heat pump system 7, is a circulation path connected by piping 25. The inverter cooling circuit 2 includes a radiator 20 that dissipates heat from the water flowing through the inverter cooling circuit 2 through heat exchange with the outside air, and a reserve tank 21 connected to the radiator 20. The inverter cooling circuit 2 also includes, for example, a pump 22, an inverter 24 to which the coolant is sent as the pump 22 rotates, and a water temperature sensor 23 that measures the temperature of the water flowing through the inverter cooling circuit 2. The inverter 24 converts DC current to AC current and supplies it to a driving motor (not shown).

For example, a heat pump system 7 for a car air conditioner is a circulation path connected by piping 70. The heat pump system 7 is equipped with an air-cooled condenser 71 that exchanges heat between the atmosphere and the refrigerant, an electric compressor 72 that is a driving source that compresses and circulates the refrigerant flowing through the heat pump system 7, an evaporator 73, an accumulator (pressure tank) 74, a chiller 75, a water-cooled condenser 76, electric expansion valves 772 and solenoid valves 773 that are arranged at various points on the piping 70.

For example, in a conventional circulating water circuit structure, there is a type in which one reserve tank is provided for each of the heater circuit and the cooling water circuit. In this circulating water circuit structure with two reserve tanks, when the heater circuit and the cooling water circuit are disconnected, the reserve tanks can release pressure for each circuit. However, the need for two reserve tanks increases costs. Also, when pouring water into an empty circuit structure, there are strict restrictions on the installation of inlets and outlets for each reserve tank in order to ensure that water can be poured in. Also, because there are two reserve tanks, it is difficult to manage the liquid level at the maximum allowable water level in each reserve tank.

For example, some conventional circulating water circuit structures connect the heater circuit and the coolant circuit with a three-way valve. In this case, regardless of whether the three-way valve is open or closed, the heater circuit and the coolant circuit are connected in one direction, and even if one reserve tank is provided only in the heater circuit, pressure between the heater circuit and the coolant circuit can be relieved with just this one reserve tank. However, this increases the cost of piping such as three-way joints and water hoses. Also, when pouring water into an empty circuit structure, there are strict restrictions on the installation of inlets and outlets for each reserve tank in order to ensure water injection. Furthermore, there is no escape route for the air present in the circuit when pouring water, which increases the number of water injections and the time it takes to pour water.

For example, in a conventional circulating water circuit structure, a four-way valve connects the heater circuit and the coolant circuit, and the heater piping of the heater circuit is directly connected to the coolant piping of the coolant circuit through a pressure relief path. In this case, regardless of whether the four-way valve is open or closed, the heater circuit and the coolant circuit are connected in one direction, and even if a single reserve tank is provided only in the heater circuit, pressure between the heater circuit and the coolant circuit can be relieved with just this one reserve tank. However, when pouring water into an empty circuit structure, there are strict restrictions on the number of inlets and outlets that can be installed in the reserve tank to ensure that water can be poured. Furthermore, water is poured in one direction within the circuit when pouring water, so it takes time to pour water.

The following describes how water is poured into the circulating water circuit structure 1 of this embodiment, which can solve the problems that existed in the conventional circulating water circuit structure described above, to make the circuit structure 1 usable. When pouring water, as shown in FIG. 2, the heater circuit 4 and the cooling water circuit 3 are set in a state where they are directly connected by the four-way valve 34. Then, the pressurized cap of the water inlet 463 of the reserve tank 46 is removed, and an operator pours water into the reserve tank 46 through the water inlet 463.

In parallel with the water being poured into the reserve tank 46, water flows from the water outlet 462 formed on the bottom 464 of the reserve tank 46 through the pump 40 of the heater circuit 4, the water-cooled condenser 41, the heater 42, the heater core 44, the fourth port 344 of the four-way valve 34, the second port 342, the cooling pipe 36 of the coolant circuit 3, the pump 30, the battery 32, the electronic unit 33, and the chiller 35 in that order. Along with the water flowing in this way, the air in the heater circuit 4 and the coolant circuit 3 that was present in the above flow path also flows to the chiller 35. Furthermore, the air moves from the water and air that flowed from the chiller 35 to the high-position pipe 361 to the air reservoir 468 of the reserve tank 46 via the pressure relief path 50 connected to the high-position pipe 361, so that the air is bled.

When pouring water, water also flows from the water inlet 461 formed on the bottom 464 of the reserve tank 46 through the third port 343 of the four-way valve 34, the first port 341, and the low-position pipe 362 of the cooling water circuit 3 in that order. Along with the water flowing in this way, the air in the heater circuit 4 and the cooling water circuit 3 that was present in the above flow path also flows to the low-position pipe 362. Furthermore, the water in the low-position pipe 362 merges with the water flowing from the water outlet 462 side in the high-position pipe 361. In addition, air moves from the water and air that flow from the low-position pipe 362 to the high-position pipe 361 to the air reservoir 468 of the reserve tank 46 via the pressure relief path 50 connected to the high-position pipe 361, so that air is bled. Therefore, the air that was present in the heater circuit 4 and the cooling water circuit 3 at the time of pouring water is properly bled.

In this way, when pouring water, air can be appropriately removed from the cooling water circuit 3 and the heater circuit 4 through the pressure relief path 50 in the reserve tank 46, thereby reducing the number of water pours and the time required for pouring water, improving the efficiency of pouring water. Note that, as in this embodiment, by forming a water inlet 461 and a water outlet 462 in the bottom 464 of the reserve tank 46, the water pouring rate into the circuit structure 1 in one pour can be increased. As a result, unlike conventional circulating water circuit structures, the circulating water circuit structure 1 of this embodiment can complete the water pouring and air bleeding operations fewer times until the water pouring is completed, shortening the water pouring time.

In addition, in the conventional circuit structure for circulating water, if the inlet position is too high, the water that flows through the circuit structure and returns falls on the liquid surface in the reserve tank, and air is drawn into the water in the reserve tank. If air gets mixed into the circuit structure, the specific heat of the water and the specific heat of the air are different, and the cooling performance and temperature control performance decrease. On the other hand, if the inlet position of the reserve tank is too low, water flows back from the inlet of the reserve tank when pouring water, and water also enters the circuit structure in the opposite direction to the flow direction of the water, blocking the air bleeding path, and air cannot be bled from anywhere in the circuit structure. Therefore, it is necessary to repeat the air bleeding operation by turning the pump after pouring water many times, and the number of times that the water pouring and air bleeding operations are performed increases. In this way, the conventional circuit structure for circulating water had mounting restrictions, but as in this embodiment, for example, the water inlet 461 and the water outlet 462 are both formed at the bottom 464 of the tank interior 460, so that the mounting restrictions on the water inlet and outlet can be relaxed compared to the conventional circuit structure for circulating water.

Next, we will explain the water flow in the heater circuit 4 and the coolant circuit 3 under normal conditions after water injection has been completed. As shown in FIG. 3, under normal conditions, the four-way valve 34 sets the disk valve 345 to the disconnection mode, and sets the heater circuit 4 and the coolant circuit 3 to a disconnected state.

When the pump 40 of the heater circuit 4 is operated, water flows through the water-cooled condenser 41, the heater 42, the heater core 44, the fourth port 344 of the four-way valve 34, the third port 343 of the four-way valve 34, and the reserve tank 46 in that order, and the heated water circulates through the heater circuit 4. Then, the heater core 44 functions to heat the interior of the electric vehicle 9.

In addition, when the pump 30 of the cooling water circuit 3 is operated, water flows through the battery 32, the electronic unit 33, the chiller 35, the first port 341 of the four-way valve 34, and the second port 342 of the four-way valve 34 in this order, and the cooled water circulates through the cooling water circuit 3 to cool the battery 32. Here, in this embodiment, the pipe diameter of the pressure relief path 50 is formed to be smaller than the pipe diameter of the cooling piping 36 of the cooling water circuit 3. In addition, the pressure relief path 50 is a single path. Therefore, when the pressure in the cooling water circuit 3 is within the allowable range, the cooled water circulating through the cooling water circuit 3 can be prevented from flowing into the heater circuit 4 through the pressure relief path 50. That is, since the thin pressure relief path 50 is filled with water in advance, the water in the pressure relief path 50 plays a role like a wall that blocks heat exchange between the heater circuit 4 and the cooling water circuit 3 whose circuit pressure is within the allowable range. This makes it possible to maintain high operating efficiency of the heater circuit 4 and the coolant circuit 3.

For example, if the cooling water circuit 3 through which water circulates and the heater circuit 4 through which water circulates are separated for a certain period of time, the pressure in the cooling water circuit 3 in which the reserve tank 46 is not provided increases. If the pressure in the cooling water circuit 3 rises to a state that is likely to exceed the allowable range, the water circulating in the cooling water circuit 3 also flows through the pressure relief path 50 and enters the reserve tank 46 of the heater circuit 4, so that the reserve tank 46 absorbs the pressure increase in the cooling water circuit 3. That is, pressure relief is performed so that the pressure in the cooling water circuit 3 falls within the allowable range. Therefore, the increase in the flow path internal pressure of the electronic device of the battery 32 arranged in the cooling water circuit 3 can be mitigated, and the reliability of the battery 32 can be improved. In addition, since the internal pressure fluctuation between the heater circuit 4 and the cooling water circuit 3 is reduced, the spring pressing the seal can ensure sealing performance even if the sealing tension force of the four-way valve 34 is reduced, and the operating efficiency of the heater circuit 4 and the cooling water circuit 3 in a mutually independent state can be maintained high. In other words, it prevents the four-way valve 34 from being unable to seal due to internal pressure fluctuations, causing the water in the heater circuit 4 and the coolant circuit 3 with different temperatures to mix when mixing is not desired. Also, since there is no need to increase the power required to switch the disk valve 345 of the four-way valve 34, electricity consumption is improved. Thus, unlike conventional circulating water circuit structures, the circulating water circuit structure 1 of this embodiment can release pressure in the coolant circuit 3 even with only one reserve tank 46.

Next, when the vehicle environment is low temperature, the four-way valve 34 switches the disk valve 345 to the direct connection mode in order to heat the battery 32 in the coolant circuit 3. This directly connects the coolant circuit 3 and the heater circuit 4 as shown in FIG. 4.

The water circulates through the pump 40 of the heater circuit 4, the water-cooled condenser 41, the heater 42, the heater core 44, the fourth port 344 of the four-way valve 34, the second port 342 of the four-way valve 34, the cooling pipe 36 of the coolant circuit 3, the pump 30, the battery 32, the electronic unit 33, the chiller 35, the first port 341 of the four-way valve 34, the third port 343, and the reserve tank 46 of the heater circuit 4 in that order. Therefore, the battery 32 is warmed by the water heated in the heater circuit 4. Note that the chiller 35 is not operating in the state shown in FIG. 4 in order to warm the battery 32.

For example, in this embodiment, as shown in FIG. 4, when the coolant circuit 3 and the heater circuit 4 are directly connected by the four-way valve 34 to warm the battery 32, the pressure relief path 50 is arranged downstream of the battery 32, which is a specified component, and upstream of the four-way valve 34, the reserve tank 46 is arranged downstream of the four-way valve 34, and the heater 42 is arranged upstream of the battery 32. Therefore, the heated water flowing through the heater circuit 4 flows into the battery 32 before the branching of the pressure relief path 50. Therefore, the warming of the battery 32 can be further promoted. In addition, in the circulation of the heated water, a part of the water that has passed through the chiller 35 flows from the pressure relief path 50 connected to the high position piping 361 to the reserve tank 46, and merges with the water that has passed through the four-way valve 34 in the reserve tank 46. Therefore, the amount of water passing through the four-way valve 34 can be reduced by the amount that the pressure relief path 50 functions as a circulation flow path, and the water resistance of the four-way valve 34 can be reduced.

Furthermore, in this embodiment, the pressure relief path 50 is not connected to the cooling pipe 36 connecting the battery 32 to the chiller 35, but is connected to the high-position pipe 361 downstream of the chiller 35 and branches off from the high-position pipe 361. Therefore, when the coolant circuit 3 and the heater circuit 4 are directly connected (when the battery 32 is being heated), the chiller 35 is not operating, but more water flows to the chiller 35 and the electronic unit 33 than when the pressure relief path 50 is configured to branch off from the cooling pipe 36 connecting the electronic unit 33 to the chiller 35 toward the reserve tank 46, or when the pressure relief path 50 is configured to branch off from the cooling pipe 36 connecting the battery 32 to the electronic unit 33 toward the reserve tank 46. That is, if the pressure relief path 50 is configured to branch off from the cooling pipe 36 connecting the electronic unit 33 to the chiller 35 toward the reserve tank 46, the water flowing through the pressure relief path 50 will relatively decrease the amount of water flowing to the electronic unit 33 (water that has lost heat from the battery 32), and the electronic unit 33 operating in the direct connection state may not be sufficiently cooled. In contrast, as shown in FIG. 4, the pressure relief path 50 is connected to the high-position pipe 361 downstream of the chiller 35 and branches off from the high-position pipe 361, so that the amount of water flowing to the electronic unit 33 will not decrease. Therefore, the cooling of the electronic unit 33 operating in the direct connection state between the cooling water circuit 3 and the heater circuit 4 is sufficiently guaranteed.

Although the embodiment of the present invention has been described above, the above-mentioned embodiment is presented as an example and is not intended to limit the scope of the present invention. This new embodiment can be embodied in various other forms. Furthermore, various omissions, substitutions, and modifications can be made without departing from the gist of the invention. Furthermore, this embodiment is included within the scope and gist of the invention, and is included in the scope of the invention and its equivalents described in the claims.

1: Circulating water circuit structure 2: Inverter cooling circuit 3: Cooling water circuit 30: Water pump 32: Battery 33: Electronic unit 34: 4-way valve 35: Chiller 36: Cooling piping 361: High-position piping 4: Heater circuit 40: Water pump 41: Water-cooled condenser 42: Heater 44: Heater core 46: Reserve tank 461: Water inlet 462: Water outlet 468: Air reservoir 48: Heater piping 50: Pressure relief path 7: Heat pump system 9: Electric vehicle

Claims (2)

a cooling water circuit for cooling a predetermined component;
a heater circuit in which a heater is provided;
a four-way valve that switches between a state in which the cooling water circuit and the heater circuit are directly connected and a state in which the cooling water circuit and the heater circuit are disconnected;
a reserve tank having an air reservoir and disposed in the heater circuit ;
In the cooling water circuit, the cooling water circulates through the predetermined component, the chiller, and the four-way valve in that order;
In the heater circuit, the cooling water circulates through the reserve tank, the heater, and the four-way valve in this order;
the cooling water circuit and the heater circuit are in communication with each other via a pressure relief path and the reserve tank;
The pressure relief path is connected to an air reservoir of the reserve tank, forming a circulating water circuit structure. one end of the pressure relief path is disposed between the chiller and the four-way valve when the cooling water circuit and the heater circuit are directly connected by the four-way valve ;
When the cooling water circuit and the heater circuit are directly connected by the four-way valve, the cooling water is circulated in the order of the reserve tank, the heater, the four-way valve, the specified part, the chiller, and the four-way valve .
The circuit structure for circulating water according to claim 1.

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