Heat management system

Abstract

[Problem] To provide a heat management system capable of preventing wasteful energy consumption and damage to individual components. [Solution] A heat management system comprising: a heat medium circuit 60 which has a heat medium heating device 83 as a heating means for heating a heat medium, and in which a heat medium for exchanging heat with a battery serving as a temperature adjustment object circulates; and a control device 200, wherein the control device 200 can execute a freezing prevention operation for preventing the heat medium from freezing by heating the heat medium using the heat medium heating device 83, and can set, on the basis of the concentration of the heat medium, a heat medium temperature threshold value for determining whether to execute the freezing prevention operation.

Description

Thermal Management System

[0001] The present invention relates to thermal management systems.

[0002] There are known technologies for preventing the heat transfer medium from freezing during air conditioning. For example, Patent Document 1 discloses a technology that applies electricity to an electric heating valve when it is determined that the water in a reservoir tank is frozen, thereby thawing the frozen water in the reservoir tank. Also, Patent Document 2 discloses a technology that uses a heating tower to prevent unnecessary heat loss by controlling the dilution amount of antifreeze.

[0003] Japanese Patent Application Laid-open No. 59-223509 Patent No. 2848714

[0004] An object of the present invention is to provide a thermal management system that can prevent wasteful energy consumption and damage to components.

[0005] According to one aspect of the present invention, a thermal management system is provided with a heat medium circuit having a heating means for heating a heat medium and through which the heat medium circulates to exchange heat with a temperature control object, and a control device, wherein the control device is capable of performing anti-freeze operation to prevent the heat medium from freezing by heating the heat medium with the heating means, and is capable of setting a threshold value for determining whether to perform anti-freeze operation based on the concentration of the heat medium.

[0006] According to the present invention, it is possible to provide a thermal management system that can prevent unnecessary energy consumption and damage to components.

[0007] Fig. 1 is a circuit diagram showing an example of the configuration of a vehicle air conditioner 1. Fig. 2 is a block diagram showing an example of the configuration of the vehicle air conditioner 1. Fig. 3 is a diagram showing an example of a flowchart showing the processing procedure when an anti-freeze operation is performed in the vehicle air conditioner 1.

[0008] <Vehicle Air Conditioner 1> Fig. 1 is an explanatory diagram showing an outline of an example configuration of a refrigerant circuit 50 and a heat medium circuit 60 included in a vehicle air conditioner 1 as a thermal management system. The vehicle air conditioner 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 vehicle air conditioner 1 includes a control device 200 (see FIG. 2 ). The control device 200 is an ECU (Electronic Control Unit) for executing various controls of the vehicle air conditioner 1. The control device 200 generates control commands based on sensor values ​​acquired from various sensors included in the vehicle air conditioner 1, user operations, and the like, and outputs the generated control commands to each component of the vehicle air conditioner 1. The vehicle air conditioner 1 is a thermal management system configured to not only regulate the temperature inside the vehicle cabin, but also regulate the temperatures of the motor and battery mounted on the vehicle, and perform anti-freeze operation for the heat medium. Note that the control device 200 may be divided into multiple ECUs for each function.

[0010] The heat medium circuit 60 is a circuit through which a heat medium flows that exchanges heat with the refrigerant circuit 50, and the heat medium transports the heat required for each part of the vehicle. The heat medium circuit 60 is configured to be able to switch between circuits according to various operations and to be in various states. Figure 1 shows one state.

[0011] The refrigerant circuit 50 includes a compressor 51, a high-temperature heat exchanger 52, a pressure reduction device 53, a low-temperature heat exchanger 54, and an accumulator 55, which are arranged to circulate a refrigerant. The refrigerant may be, for example, but is not limited to, a hydrofluoroolefin. The refrigerant circuit 50 is configured to function as a heat pump. That is, the refrigerant circulating through the refrigerant circuit 50 is compressed, condensed, expanded, and evaporated in the compressor 51, the high-temperature heat exchanger 52, the pressure reduction device 53, and the low-temperature heat exchanger 54, respectively, and these processes are repeated.

[0012] In the high-temperature side heat exchanger 52 or the low-temperature side heat exchanger 54 of the refrigerant circuit 50, heat is exchanged between the heat medium in the heat medium circuit 60 and the refrigerant. The heat medium is a fluid such as a coolant liquid. The heat medium circulates through various parts of the vehicle to heat or cool the parts and transport heat from one part to another.

[0013] The vehicle air conditioning device 1 includes an HVAC (Heating, Ventilation, and Air Conditioning) unit 70. The HVAC unit 70 includes a heater core 71 and a cooler core 72 that constitute a part of a heat medium circuit 60. The heater core 71 of the heat medium circuit 60 is configured to circulate a heat medium heated by the high-temperature side heat exchanger 52. The heater core 71 is configured to heat air to be supplied into the vehicle cabin. The heater core 71 can be used to heat the vehicle cabin. The cooler core 72 of the heat medium circuit 60 is configured to circulate a heat medium cooled by the low-temperature side heat exchanger 54. The cooler core 72 is configured to cool the air to be supplied into the vehicle cabin. The cooler core 72 can be used to cool the vehicle cabin.

[0014] The HVAC unit 70 includes an intake unit 75 that takes in outside air or inside air, and a blower 76 that supplies the air taken in through the intake unit 75 to an air flow passage. A cooler core 72 is installed upstream of the air flow passage. A heater core 71 is installed in a heater core passage 78 downstream of the air flow passage. A bypass passage 79 is formed in parallel with the heater core passage 78 in which the heater core 71 is installed. The flow of air into the heater core passage 78 or the bypass passage 79 is adjusted by an air mix damper 77. With this configuration, the air that passes through the heater core 71 or the cooler core 72 is heated or cooled and then conditioned, and sent into the vehicle cabin.

[0015] The heat medium circuit 60 includes a motor temperature regulator 81, a battery temperature regulator 82, a heat medium heater 83, and an exterior heat exchanger 84. The motor temperature regulator 81 is configured so that the heat medium flowing through the motor temperature regulator 81 can exchange heat with the motor. The motor is heated or cooled by the heat medium flowing through the motor temperature regulator 81. The battery temperature regulator 82 is configured so that the heat medium flowing through the battery temperature regulator 82 can exchange heat with the battery. The battery is heated or cooled by the heat medium flowing through the battery temperature regulator 82. Note that a configuration similar to the battery temperature regulator 82 can also be applied to an in-vehicle device temperature regulator for regulating the temperature of other in-vehicle devices that require temperature regulation, not just the battery. The heat medium heater 83 is configured to generate heat using electric power and heat the heat medium. Heating the heat medium by the heat medium heater 83 can heat a battery, for example, even when there is no other heat source. The outdoor heat exchanger 84 is configured so that the heat medium flowing through the outdoor heat exchanger 84 can exchange heat with the outdoor air. In the outdoor heat exchanger 84, the heat medium can release heat to the outdoor air and absorb heat from the outdoor air.

[0016] Each component, such as the heater core 71, the cooler core 72, the motor temperature regulator 81, the battery temperature regulator 82, the heat medium heater 83, and the exterior heat exchanger 84, is connected to a flow path through which the heat medium flows. These flow paths are connected to an eight-way valve 61, a four-way valve 62, a three-way valve 63, etc. The eight-way valve 61, the four-way valve 62, the three-way valve 63, etc., switch the connections of the flow paths, so that the heat medium circuit 60 can form various circulation circuits. A plurality of pumps 64 are provided in these flow paths. The pumps 64, by their operation, can circulate the heat medium in the formed circulation circuits.

[0017] <Controller 200> FIG. 2 is an explanatory diagram showing an outline of an example of the configuration of the controller 200 included in the vehicle air conditioner 1. As shown in FIG.

[0018] The control device 200 includes a processor 201, a memory 202, a storage 203, and an interface 204. The processor 201 is, for example, a central processing unit (CPU) or a microprocessing unit (MPU). The memory 202 is, for example, a random access memory (RAM). The storage 203 is a rewritable nonvolatile memory such as a hard disk drive (HDD), a solid state drive (SSD), or a flash memory. The storage 203 stores system programs including an operating system (OS) and control programs including computer-readable code required for control calculations. The processor 201 reads the system programs and control programs, expands them into the memory 202, and executes them to perform various processes. The interface 204 controls communication between the control device 200 and components of the vehicle air conditioner 1.

[0019] The control device 200 controls the operation of the vehicle air conditioner 1 in accordance with the operation required of the vehicle (e.g., air conditioning inside the vehicle), thereby selectively forming one or more circuits through which the heat medium circulates in the heat medium circuit 60. Furthermore, the control device 200 controls the operation of the heat medium heating device 83 to control the temperature of the heat medium in the heat medium circuit 60.

[0020] The control device 200 receives detection information from various sensors 210 included in the vehicle air conditioner 1. The sensors 210 include a blown air temperature sensor that detects the temperature of air blown into the vehicle cabin, an outside air temperature sensor that detects the outside air temperature, a refrigerant temperature sensor that detects the temperature of the refrigerant circulating through the refrigerant circuit 50, a refrigerant pressure sensor that detects the pressure of the refrigerant circulating through the refrigerant circuit 50, a vehicle interior temperature sensor that detects the temperature inside the vehicle cabin, a rotation speed detection sensor that detects the rotation speed of the compressor 51, a heat medium temperature sensor that detects the temperature of the heat medium circulating through the heat medium circuit 60, and a sensor that measures the concentration of the heat medium circulating through the heat medium circuit 60.

[0021] Based on detection information from various sensors 210, the control device 200 controls the operation of the compressor 51 and pressure reducing device 53 in the refrigerant circuit 50, the selection of the path in the heat medium circuit 60, the operation of the pump 64, and the operation of the heat medium heating device 83.

[0022] [Operation of the Vehicle Air Conditioner 1] A specific operation of the vehicle air conditioner 1 will be described.

[0023] <Execution of Anti-Freeze Operation> At extremely low temperatures, the heat medium circulating in the circuit may freeze. Therefore, at extremely low temperatures, it is necessary to operate a heat medium heating means according to the outside air temperature. The heating means, for example, heats the heat medium using a heat medium heating device 83. However, the freezing temperature of the heat medium varies depending on its concentration. Therefore, if the heat medium is heated based on the outside air temperature without considering the freezing temperature of the heat medium, the heat medium may be heated before its temperature reaches the freezing temperature. In this case, the heat medium may be overheated even though the heat medium is circulatable. As a result, unnecessary heating operation to heat the heat medium results in unnecessary energy consumption, and the excessive heating operation may cause overloading of components, potentially resulting in damage to the components.

[0024] Therefore, in the vehicle air conditioning device 1 of this embodiment, in order to solve the problems that arise when heating the heat medium circulating through the heat medium circuit 60 in accordance with the outside air temperature when preventing the heat medium circulating through the heat medium circuit 60 from freezing, the control device 200 is capable of performing anti-freeze operation to prevent the heat medium circulating through the heat medium circuit 60 from freezing by heating the heat medium using the heat medium heating device 83, and is also capable of setting a threshold value for the temperature of the heat medium for determining whether or not to perform anti-freeze operation based on the concentration of the heat medium.

[0025] The specific processing performed by the control device 200 when performing the anti-freeze operation will be described below with reference to FIG.

[0026] As shown in FIG. 3, the control device 200 acquires the concentration information of the heat medium (S1).

[0027] One method for acquiring the concentration information is for a vehicle maintenance worker or user to input a value of the heat medium concentration measured in advance outside the vehicle into the vehicle, and for the control device 200 to acquire the heat medium concentration based on the input value. In this case, for example, the heat medium concentration data can be input in a maintenance information input mode of the navigation system.

[0028] Another method for acquiring the concentration information is to provide a sensor for measuring the concentration of the heat medium in the heat medium circuit 60, and have the control device 200 acquire the concentration of the heat medium based on the value of the sensor.

[0029] Another method for acquiring concentration information is, for example, a method in which the control device 200 acquires the concentration of the heat medium based on the power consumption of the pump 64. That is, when the concentration of the heat medium changes, the viscosity of the heat medium changes, and therefore the power consumption required to circulate the heat medium by the pump 64 changes. This method utilizes this relationship to acquire the concentration of the heat medium based on the power consumption of the pump 64. Specifically, the control device 200 stores data that associates the temperature of the heat medium, the concentration of the heat medium, and the power consumption of the pump 64. The control device 200 then searches the data to acquire the concentration of the heat medium based on the power consumption of the pump 64.

[0030] Next, the control device 200 estimates the freezing temperature of the heat medium based on the concentration of the heat medium acquired in step S1 (S2). Specifically, the control device 200 has data indicating the correspondence relationship between the concentration of the heat medium and the freezing temperature of the heat medium. The control device 200 then searches the data and identifies the freezing temperature of the heat medium corresponding to the concentration of the heat medium acquired in step S1, thereby estimating the freezing temperature of the heat medium.

[0031] Next, the control device 200 sets a threshold value for the temperature of the heat medium for determining whether or not to perform anti-freeze operation (S3). At this time, the control device 200 sets the threshold value to the freezing temperature of the heat medium estimated in step S2.

[0032] Next, the control device 200 determines whether the temperature of the heat medium is equal to or lower than a threshold value (S4). When the control device 200 determines that the temperature of the heat medium is equal to or lower than the threshold value (S4: Yes), the control device 200 determines whether the next trip is scheduled (S5). Whether the next trip is scheduled is determined based on, for example, whether the user has reserved pre-temperature control, whether the vehicle's driving system is activated, and learning data of the vehicle.

[0033] Next, when the control device 200 determines that the next trip is scheduled (S5: Yes), it performs anti-freeze operation (S6). The control device 200 performs anti-freeze operation by heating the heat medium using the heat medium heating device 83. Note that if the target temperature of the heat medium requested by the vehicle air conditioner 1 is below a threshold, the anti-freeze operation is performed with priority. Furthermore, when performing pre-air conditioning or when performing air conditioning at the start of the driving system, the control device 200 performs anti-freeze operation before performing air conditioning. This makes it possible to avoid a situation in which the heat medium freezes and air conditioning becomes impossible.

[0034] Furthermore, the control device 200 sets a target temperature of the heat medium when performing the freeze prevention operation. At this time, if the target temperature of the heat medium is set near the threshold value, the power consumption required for performing the freeze prevention operation can be reduced. On the other hand, if the target temperature of the heat medium is set to a temperature that is higher than the threshold value by a predetermined temperature or more, the battery can be brought closer to an appropriate temperature while reliably preventing the heat medium from freezing.

[0035] In addition, when the control device 200 determines that the temperature of the heat medium will not fall below the threshold value (S4: No), or when it determines that there is no next scheduled trip (S5: No), it ends the processing without performing anti-freeze operation.

[0036] As described above, the control device 200 sets a threshold value in step S3 and then performs anti-freeze operation in step S6, thereby reliably preventing the heat medium from freezing while suppressing the execution of anti-freeze operation of the heat medium at unnecessary times. This prevents the waste of energy caused by extra heating operation to heat the heat medium and the damage to each component that can occur due to overloading of the components caused by extra heating operation.

[0037] Furthermore, the control device 200 performs anti-freeze operation when the temperature of the heat medium falls below a threshold value, thereby reliably preventing the heat medium from freezing while suppressing the execution of anti-freeze operation of the heat medium at unnecessary times. This prevents unnecessary energy consumption due to extra heating operation to heat the heat medium and damage to components that could be caused by overloading them due to extra heating operation.

[0038] In this embodiment, an example is given in which anti-freeze operation is performed when the next trip is scheduled, but it is also possible to constantly monitor whether the temperature of the heat medium falls below a threshold and perform anti-freeze operation even when the next trip is not scheduled.

[0039] [Advantages of the Present Embodiment] (1) The vehicle air conditioner 1 as a thermal management system includes a heat medium circuit 60 having a heat medium heating device 83 as a heating means for heating the heat medium, through which the heat medium circulates to exchange heat with a battery as a temperature control target, and a control device 200, wherein the control device 200 is capable of performing an anti-freeze operation to prevent the heat medium from freezing (S6 in FIG. 3 ) and is also capable of setting a threshold value for the temperature of the heat medium for determining whether to perform the anti-freeze operation based on the concentration of the heat medium (S1 to S3 in FIG. 3 ). Therefore, the control device 200 can reliably prevent the heat medium from freezing while suppressing the execution of the anti-freeze operation of the heat medium at unnecessary times, thereby preventing unnecessary energy consumption due to excessive heating operation to heat the heat medium and damage to components due to overloads caused by excessive heating operation.

[0040] In this embodiment, an example has been given in which a heat medium heating device 83 is used as the heating means, but a means different from that of this embodiment may also be used as the heating means, for example, by using the refrigerant flowing through the hot gas heating circuit as the heating means and performing anti-freeze operation by heat exchange between the refrigerant and the heat medium.

[0041] (2) The control device 200 executes the anti-freeze operation when the temperature of the heat medium falls below a threshold value (S4, S6 in FIG. 3). This ensures that the heat medium is prevented from freezing while suppressing the execution of the anti-freeze operation at unnecessary times. This prevents unnecessary energy consumption due to extra heating operation to heat the heat medium and damage to components that could be caused by overloading the components due to extra heating operation.

[0042] (3) The control device 200 executes the freeze prevention operation to set the target temperature of the heat medium close to the threshold value, thereby reducing the power consumption required to execute the freeze prevention operation.

[0043] (4) The control device 200 executes the freeze prevention operation to set the target temperature of the heat medium to a temperature that is higher than the threshold by a predetermined temperature or more. This allows the battery to be brought closer to an appropriate temperature while reliably preventing the heat medium from freezing.

[0044] 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.

[0045] 1: Vehicle air conditioning device 200: Control device

Claims

1. A thermal management system comprising: a heat medium circuit having a heating means for heating a heat medium, through which the heat medium circulates to exchange heat with a temperature control target; and a control device, wherein the control device is capable of performing anti-freeze operation to prevent the heat medium from freezing by heating the heat medium with the heating means, and is capable of setting a threshold value for the temperature of the heat medium for determining whether or not to perform the anti-freeze operation based on the concentration of the heat medium.

2. The thermal management system according to claim 1, wherein the control device executes anti-freeze operation when the temperature of the heat medium falls below the threshold value.

3. The thermal management system according to claim 2, characterized in that the control device sets the target temperature of the heat medium to near the threshold value by executing anti-freeze operation.

4. The thermal management system according to claim 2, characterized in that the control device sets the target temperature of the heat medium to a temperature that is higher than the threshold by a predetermined temperature or more by performing anti-freeze operation.

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