JP2023149803A - Heat management system for vehicle - Google Patents

Abstract

To provide a technology which can defrost efficiently by using a heat medium.SOLUTION: In a heat management system, a heating operation may be switched to a defrosting operation when it is specified that a heat medium circulating between a heat related device path and a bypass path has a predetermined temperature or a higher temperature in the heating operation.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The technology disclosed herein relates to a thermal management system for a vehicle.

Patent Document 1 discloses a heat pump system mounted on a vehicle. In the heat pump system, when it is determined that frost has formed on the outdoor heat exchanger, the outdoor heat exchanger is defrosted using the heat medium of the heat pump system.

Japanese Patent Application Publication No. 2017-133823

If the heat medium used for defrosting does not have sufficient heat storage, defrosting may not be performed efficiently. This specification provides a technique that can efficiently defrost using a heat medium.

The thermal management system disclosed herein is used in a vehicle. The thermal management system is a thermal circuit in which a heat medium circulates, and includes a heat exchanger path, a radiator path communicating with the heat exchanger path, and a heat-related equipment path communicating with the radiator path. a bypass path that bypasses the radiator path and communicates with the heat-related equipment path; a heat exchanger that cools the heat medium in the heat exchanger path by heat exchange; a radiator for exchanging heat between the heat medium in the radiator path and outside air; a control valve for changing the flow path of the heat medium in the heat circuit; and a control valve for changing the flow path of the heat medium in the heat circuit; a first pump capable of delivering the heat medium in the thermal circuit from the heat-related equipment route to the radiator route, and a first pump capable of delivering the heat medium in the thermal circuit from the heat-related equipment route to the radiator route, and from the heat-related equipment route to the bypass route; a second pump capable of pumping, and a control device, the control device controlling the control valve and the first pump so that the heat medium circulates between the heat exchanger path and the radiator path. and controlling the control valve and the second pump so that the heat medium circulates between the heat-related equipment path and the bypass path, the heating operation comprising controlling the heating medium by the radiator in the radiator path. heating the heating medium in the heat-related equipment path and heating the heating medium in the heat-related equipment path by the heat-related equipment on the heat-related equipment path; performing a defrosting operation of controlling the control valve and the second pump so that the heating medium circulates between them, and cooling the heating medium in the radiator path by the radiator. In the heating operation, when it is specified that the heat medium circulating between the heat-related equipment path and the bypass path is at a predetermined temperature or higher, the control device changes the defrosting from the heating operation. You may switch to action.

During heating operation, the heat medium absorbs heat in the radiator, so frost is likely to form on the radiator. When frost forms on the radiator, the heating medium is heated in the heat-related equipment and sent to the radiator path. If heating by heat-related equipment is not sufficient, even if heated heat medium is sent to the radiator path, defrosting the radiator takes time and is not efficient. According to the above configuration, the defrosting operation can be performed when it is determined that heat is sufficiently stored in the heat medium circulating between the heat-related equipment path and the bypass path. That is, the defrosting operation can be performed when sufficient heat is stored in the heating medium. Thereby, defrosting can be efficiently performed using the heat medium.

FIG. 1 is a diagram showing a thermal management system 100 that performs a heating operation. FIG. 1 is a diagram showing a thermal management system 100 that performs a defrosting operation. It is a flowchart of defrosting processing.

Technical elements of the thermal management device disclosed in this specification are listed below. Note that each of the following technical elements is independently useful.

In one example of the thermal management system disclosed in this specification, the control device may specify the temperature of the heat medium circulating between the heat-related equipment path and the bypass path depending on the driving state of the vehicle.

According to this configuration, it is not necessary to provide a sensor that detects the temperature of the heat medium circulating between the heat-related equipment path and the bypass path.

In one example of the thermal management system disclosed herein, the control device may switch from the heating operation to the defrosting operation when it is further determined that frost is attached to the radiator during the heating operation.

According to this configuration, when it is determined that frost is attached to the radiator, the defrosting operation can be performed.

In an example thermal management system disclosed herein, the control device may use the temperature of the heat medium heated by the radiator to identify that frost is attached to the radiator.

According to this configuration, it is possible to easily identify frost formation on the radiator using the temperature of the heating medium.

(First example)
(Structure of thermal management system 100)
A thermal management system 100 according to an embodiment will be described with reference to the drawings. The thermal management system 100 of this embodiment is mounted on an electric vehicle, and by circulating a heat medium such as antifreeze or refrigerant, heats and cools components provided in the electric vehicle, and performs air conditioning inside the vehicle. As shown in FIG. 1, the thermal management system 100 includes a low temperature radiator circuit 10 having a low temperature radiator 42, a high temperature radiator circuit 30 having a high temperature radiator 94, and thermally intervening between the two radiator circuits 10, 30. The heat pump circuit 20 inserted therein and a control device 98 are provided. These circuits 10, 20, and 30 are thermally connected, but the paths through which the heat medium flows are independent from each other. Although not particularly limited, the two radiator circuits 10 and 30 employ an antifreeze liquid such as a long-life coolant as a heat medium. On the other hand, the heat pump circuit 20 uses a refrigerant (heat medium for refrigeration cycle) such as hydrofluorocarbon as a heat medium.

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

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

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

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

The second circuit 16 mainly includes a low temperature radiator path 17, a heat-related equipment path 18, and a bypass path 19. The upstream end of the low-temperature radiator path 17 and the downstream end of the heat-related equipment path 18 are connected via a switching valve 40. The downstream end of the low temperature radiator path 17 and the upstream end of the heat-related equipment path 18 are connected via a reservoir tank 69. The low temperature radiator 42 is shared between the first circuit 12 and the second circuit 16. By doing so, the low temperature radiator circuit 10 can be configured efficiently.

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

Bypass path 19 bypasses low temperature radiator 42 . The bypass path 19 branches at a switching valve 40 at the connection point between the low temperature radiator path 17 and the heat-related equipment path 18, bypasses the low temperature radiator 42, and joins the reservoir tank 69 at the downstream end of the low temperature radiator path 17. ing.

The control device 98 is configured as a so-called computer including at least one processor and a memory. A computer program for controlling the thermal management system 100 and information necessary for controlling the thermal management system 100 are stored in the memory. The processor controls thermal management system 100 based on computer programs and information stored in memory.

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

The control device 98 can switch the flow path between heating operation and defrosting operation using the switching valve 40. Figure 1 shows the heating operation. In the heating operation, the first flow path C1 and the second flow path C2 are separated. The heat medium flows through the first flow path C1 and the second flow path C2 independently of each other. The first flow path C1 is a flow path in which a heat medium is circulated between the low temperature radiator 42 and the chiller 70 using the first pump 68. The heat absorbed from the outside air by the low-temperature radiator 42 can be supplied to the chiller 70 through the first flow path C1. The second flow path C2 uses a second pump 60 to distribute the heat medium between the heat-related equipment path 18 and the bypass path 19 in order to cool a plurality of heat-related equipment (i.e., oil cooler 54, SPU 56, and PCU 58). This is a flow path for circulation. By circulating the heat medium through the second flow path C2 without going through the low-temperature radiator 42, the heat-related devices 54, 56, and 58 can be cooled. The heat-related devices 54, 56, and 58 generate more heat than the battery 66. According to this configuration, the heat-related devices 54, 56, and 58 can be cooled without using the low-temperature radiator 42 in a situation where the heat medium cannot radiate heat in the low-temperature radiator 42 due to heating.

FIG. 2 shows the defrosting operation. In the defrosting operation, the heat-related equipment path 18 and the low-temperature radiator path 17 are connected to form a third flow path C3. The third flow path C3 is a flow path in which a heat medium is circulated between the low temperature radiator 42 and several heat-related devices 54, 56, and 58 using the second pump 60. The second flow path C2 allows the heat medium that has absorbed heat in the heat-related equipment to flow into the low-temperature radiator 42. Thereby, the low temperature radiator 42 can be heated.

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

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

(Configuration of high temperature radiator circuit 30)
The high temperature radiator circuit 30 mainly includes a main circuit 32 and a heating path 34. The main circuit 32 of the high temperature radiator circuit 30 is a circulation path that circulates a heat medium between the capacitor 84 and the high temperature radiator 94. The main circuit 32 is provided with a third pump 88 for circulating the heat medium. The main circuit 32 releases the heat transferred from the heat pump circuit 20 from the high temperature radiator 94 to the outside air by circulating the heat medium. Note that the main circuit 32 is further provided with a heater 86.

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

In the thermal management system 100, the control device 98 rearranges the routes of the low-temperature radiator circuit 10, the heat pump circuit 20, and the high-temperature radiator circuit 30 in accordance with instructions from the vehicle's ECU, thereby controlling heating, cooling, and the temperature of the battery 66 in the vehicle. Thermal management of the vehicle is performed, such as conditioning and cooling of heat-related equipment 54, 56, 58.

(defrosting treatment)
In the thermal management system 100, when the temperature of the low-temperature radiator 42 decreases during heating operation, frost may adhere to the low-temperature radiator 42. If frost adheres to the low-temperature radiator 42, it may become an obstacle to heat exchange of the heat medium in the radiator. In the thermal management system 100, a defrosting process is performed to defrost the frost attached to the low-temperature radiator 42.

The control device 98 starts defrosting processing when the heating operation is started. As shown in FIG. 3, in the defrosting process, the temperature of the heat medium passing through the low-temperature radiator 42 is acquired in S12. Specifically, the control device 98 acquires the heat medium temperature detected by the third temperature sensor 63. Next, in S14, the control device 98 determines whether frost has adhered to the low temperature radiator 42. Specifically, the control device 98 determines that frost is attached to the low-temperature radiator 42 when the temperature of the heat medium passing through the low-temperature radiator 42 obtained in S12 is lower than the first predetermined temperature (S14 (Yes) The control device 98 determines that frost does not adhere to the low-temperature radiator 42 when the temperature of the heat medium passing through the low-temperature radiator 42 obtained in S12 is equal to or higher than the first predetermined temperature (NO in S14).

The first predetermined temperature is the temperature of the heat medium that is estimated to have frost on the low-temperature radiator 42, and is, for example, a temperature that is 5° C. or more lower than the outside temperature. The first predetermined temperature is specified in advance through experiments, simulations, etc., and is stored in the control device 98. If NO in S14, the process advances to S24. In the case of NO in S14, there is a low possibility that frost is attached to the low temperature radiator 42, and there is no need to perform the defrosting operation. In this case, the control device 98 proceeds to S24 without performing the defrosting operation. On the other hand, if YES in S14, the control device 98 acquires the temperature of the heat medium flowing through the second flow path C2 detected by the second temperature sensor 62 in S16. The second temperature sensor 62 detects the temperature of the heat medium on the upstream side of the PCU 62 .

Next, in S18, the control device 98 determines whether the heat medium temperature obtained in S16 is equal to or higher than the second predetermined temperature. The second predetermined temperature is a temperature at which it is determined that the heat medium stores the amount of heat necessary to defrost the frost adhering to the low-temperature radiator 42, and is, for example, 12°C. The process of S18 can be rephrased as the control device 98 determining whether the heat medium flowing through the second flow path C2 stores the amount of heat necessary to defrost the frost adhering to the low-temperature radiator 42. . The second predetermined temperature is appropriately determined depending on the dimensions of the low-temperature radiator 42, the volume of the second flow path C2, and the like. The second predetermined temperature is specified in advance through experiments, simulations, etc., and is stored in the control device 98.

When it is determined that the acquired heating medium temperature is equal to or higher than the second predetermined temperature in S16, that is, the amount of heat required for the heating medium flowing through the second flow path C2 to defrost the frost adhering to the low-temperature radiator 42. If it is determined that the temperature is stored (YES in S18), in S20, the control device 98 switches the thermal management system 100 from heating operation to defrosting operation. Specifically, the control device 98 switches the switching valve 40 from a state where the first flow path C1 and the second flow path C2 are separated to a state where the third flow path C3 is formed. The controller 98 further stops the first pump 68. Thereby, the second pump 60 causes the heat medium to flow through the third flow path C3. As a result, the heat medium heated by the plurality of heat-related devices flows toward the low-temperature radiator 42 . Thereby, the low temperature radiator 42 is heated and defrosted. The control device 98 further stops the circulation of the heat medium in the heat pump circuit 20 by stopping the compressor 82 . In the defrosting operation, the path of the heat medium in the high temperature radiator circuit 30 is the same as in the heating operation. Thereby, heating of the interior of the vehicle is continued using the heater core 92.

In S22, the control device 98 monitors that a predetermined period of time has elapsed since the defrosting operation was performed. If the predetermined period has elapsed (YES in S22), the process advances to S23. The predetermined period is a period during which frost adhering to the low temperature radiator 42 is defrosted, and is, for example, 5 minutes. In a modification, the predetermined period may change depending on the heat medium temperature acquired in S16. For example, the predetermined period may be set to be shorter as the heat medium temperature obtained in S16 is higher.

When it is determined that the acquired heating medium temperature is less than the second predetermined temperature in S16, that is, the amount of heat required for the heating medium flowing through the second flow path C2 to defrost the frost adhering to the low-temperature radiator 42. If it is determined that the information is not stored (NO in S18), the process advances to S24. In the case of NO in S18, even if the defrosting operation is executed, the defrosting is difficult to proceed because a sufficient amount of heat is not stored in the heating medium. With the defrosting process, it is not necessary to perform defrosting in such a situation. According to this configuration, defrosting can be efficiently performed using a heat medium. Thereby, it is possible to suppress a decrease in the electricity consumption of the vehicle.

In S23, the control device 98 switches from defrosting operation to heating operation. Next, in S24, the control device 98 determines whether the heating operation should be ended. When the vehicle interior heating should be terminated due to the interior temperature or the passenger's operation, the vehicle ECU transmits a termination signal to the control device 98 indicating that the heating operation is to be terminated. When the end signal is received, the control device 98 determines that the heating operation should be ended (YES in S24), and ends the defrosting process. The control device 98 terminates the heating operation and executes other heat management in accordance with the instructions from the ECU. On the other hand, if the end signal is not received, the control device 98 determines that the heating operation should not be ended (NO in S24), and returns to S12.

In the defrosting process, it is determined whether or not frost is attached to the low-temperature radiator 42 using the temperature of the heat medium flowing through the low-temperature radiator 42 . According to this configuration, it is possible to easily determine whether or not frost has adhered to the low-temperature radiator 42.

(Second example)
The thermal management system 100 of this embodiment does not include the second temperature sensor 62. The rest of the configuration of the thermal management system 100 is the same as that of the thermal management system 100 of the first embodiment.

In the defrosting process, the control device 98 does not execute the process of S16. In S18, the control device 98 determines whether the temperature of the heat medium, which is specified using the running state of the vehicle, is equal to or higher than the second predetermined temperature, that is, whether the heat medium flowing through the second flow path C2 reaches the low-temperature radiator 42. Determine whether the amount of heat necessary to defrost the adhering frost is stored. Specifically, the control device 98 controls the control device 98 when the vehicle is in an idle state, that is, when the electric vehicle is started but not running, and when the load on the motor built in the transaxle 48 is low, such as when there is a traffic jam. In a relatively low state, the control device 98 determines that the temperature of the heat medium is less than the second predetermined temperature (NO in S18). On the other hand, in a state other than a state in which the vehicle is not running or a state in which the load on the motor built in the transaxle 48 is relatively low, such as in a traffic jam, the control device 98 controls the temperature of the heat medium to be equal to or higher than the second predetermined temperature. It is determined that there is one (YES in S18).

In the modified example, in S18, the control device 98 calculates the integrated value of the current supplied to the motor built in the transaxle 48, the power consumption of the compressor 82 in the heating operation, and the amount of heat medium circulating in the heat pump circuit 20 in the heating operation. At least one of the temperatures may be used to determine whether the temperature of the heat medium is equal to or higher than the second predetermined temperature.

Although the embodiments have been described in detail above, these are merely examples and do not limit the scope of the claims. The techniques described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness singly or in various combinations, and are not limited to the combinations described in the claims as filed. Further, the techniques illustrated in this specification or the drawings simultaneously achieve multiple objectives, and achieving one of the objectives has technical utility in itself.

(Modified example)
In this embodiment, in the defrosting process, the control device 98 determines whether frost is attached to the low temperature radiator 42 (S12 and S14). However, the control device 98 may execute the processing from S16 onward without determining whether frost is attached to the low-temperature radiator 42. For example, the control device 98 may execute the processes from S16 onwards when a predetermined condition such as the heating operation being continued for a predetermined period is satisfied. The predetermined condition may be a condition for frost to adhere to the low temperature radiator 42.

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

10: Low temperature radiator circuit, 20: Heat pump circuit, 30: High temperature radiator circuit, 40: Switching valve, 42: Low temperature radiator, 98: Control device, 100: Thermal management system

Claims (4)

A thermal management system for a vehicle,
A thermal circuit in which a heat medium circulates, the heat exchanger path, a radiator path communicating with the heat exchanger path, a heat-related equipment path communicating with the radiator path, and bypassing the radiator path. and a bypass path communicating with the heat-related equipment path;
a heat exchanger that cools the heat medium in the heat exchanger path by heat exchange;
a radiator that exchanges heat between the heat medium in the radiator path and outside air;
a control valve that changes the flow path of the heating medium in the thermal circuit;
a first pump capable of delivering the heat medium in the thermal circuit from the heat exchanger path to the radiator path;
a second pump capable of delivering the heat medium in the thermal circuit from the heat-related equipment path to the radiator path and from the heat-related equipment path to the bypass path;
comprising a control device;
The control device includes:
The control valve and the first pump are controlled so that the heat medium circulates between the heat exchanger path and the radiator path, and the heat medium is circulated between the heat-related equipment path and the bypass path. heating operation for controlling the control valve and the second pump so that the heating medium is circulated by the radiator, and the heat medium in the radiator path is heated by the heat-related equipment on the heat-related equipment path; the heating operation of heating the heat medium in the heat-related equipment path;
A defrosting operation that controls the control valve and the second pump so that the heat medium circulates between the heat-related equipment path and the radiator path, the defrosting operation controlling the heat medium in the radiator path by the radiator. performing the defrosting operation to cool the
The control device switches the heating operation from the heating operation to the defrosting operation when it is specified that the heat medium circulating between the heat-related equipment path and the bypass path has a predetermined temperature or higher in the heating operation. Switchable thermal management system. The heat management system according to claim 1, wherein the control device specifies the temperature of the heat medium circulating between the heat-related equipment path and the bypass path depending on a running state of the vehicle. The thermal management system according to claim 1 or 2, wherein the control device switches from the heating operation to the defrosting operation when it is further specified that frost is attached to the radiator in the heating operation. . The thermal management system according to claim 3, wherein the control device uses the temperature of the heat medium heated by the radiator to identify that frost is attached to the radiator.

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