Vehicle heat management device

Abstract

The present invention relates to a heat management device for a vehicle, which, when switching from a first mode in which there is a heating request from an air conditioner and there is a cooling request from a battery to a second mode in which there is a heating request from the air conditioner and there is no cooling request from the battery, reduces the degree of opening of an electric expansion valve of a refrigerant circuit for a predetermined period of time. After the predetermined period has elapsed, the first mode is switched to the second mode.

Description

Technical Field

[0001] The present disclosure relates to a thermal management device for a vehicle. Background Art

[0002] Japanese Patent Application Laid-Open No. 2020-165604 discloses a refrigerant circuit device for an air conditioning device of a battery electric vehicle. In the refrigerant circuit device, the heat of the battery (storage battery) and the outside air absorbed by a cooler arranged in the refrigerant circuit (heat pump cycle) is used for heating the interior of the vehicle. The heat of the battery and the outside air is absorbed in the cooler by the low-temperature side heat medium circuit. Summary of the invention

[0003] The refrigerant circuit device of Japanese Patent Laid-Open No. 2020-165604 has a heating mode and a cooling and heating mode. The heating mode heats the vehicle interior without cooling the battery. In the cooling and heating mode, the heat absorbed when the battery is cooled is used to heat the vehicle interior. Therefore, when switching from the cooling and heating mode to the heating mode, heat is no longer absorbed from the battery. The temperature of the low-temperature side heat medium flowing into the cooler drops. The refrigerant flowing into the compressor of the refrigerant circuit becomes a liquid phase or a gas-liquid mixed phase state. A malfunction occurs in the compressor. In Japanese Patent Laid-Open No. 2020-165604, when the low-temperature side heat medium circuit (low-temperature side circuit) stops cooling the battery, the speed of the compressor is reduced, or the opening of the expansion valve that decompresses the refrigerant flowing into the cooler is reduced. As a result, the flow rate of the refrigerant flowing into the cooler is reduced, and the occurrence of liquid reflux of the liquid-phase refrigerant flowing into the compressor is suppressed.

[0004] When the opening degree of the expansion valve is reduced, a response delay may occur. In this case, the flow rate of the refrigerant flowing into the cooler becomes too large temporarily, and there is a concern that the occurrence of liquid backflow of the liquid-phase refrigerant flowing into the compressor cannot be suppressed.

[0005] An object of the present disclosure is to suppress the refrigerant flowing into a compressor of a refrigerant circuit from becoming a liquid phase or a gas-liquid mixed phase state even when a response delay of an expansion valve occurs.

[0006] The thermal management device of a vehicle according to the present disclosure comprises:

[0007] A refrigerant circuit includes a compressor for compressing and ejecting the refrigerant flowing out of the cooler, a condenser for releasing heat of the refrigerant ejected from the compressor, and an expansion valve for decompressing the refrigerant flowing out of the condenser, wherein the cooler exchanges heat between the refrigerant decompressed by the expansion valve and a low-temperature side heat medium;

[0008] The low temperature side circuit has a heat exchange device that allows the low temperature side heat medium to absorb heat from the battery, heat from the vehicle drive device, and heat from the outside air;

[0009] Air conditioning units that use the heat released by the condenser to provide heating; and

[0010] Control device.

[0011] The control device consists of:

[0012] In a first state where there is a heating request and a battery cooling request, the opening of the expansion valve is controlled to a predetermined opening, and the battery is cooled and heated by heat exchange between the refrigerant and the low-temperature side heat medium that has absorbed the heat of the battery in the cooler.

[0013] When switching from the first state to the second state in which heating is requested but cooling is not requested, the opening of the expansion valve is made smaller than a predetermined opening within a predetermined period of time, and then the first state is switched to the second state.

[0014] In the second state, the low-temperature side heat medium does not flow toward the heat exchanger of the battery.

[0015] According to this structure, the refrigerant in the refrigerant circuit absorbs heat from the low-temperature side heat medium that absorbs heat from the battery, the vehicle drive device, and the outside air in the cooler, and releases the heat in the condenser to be used for heating. Thus, the heat from the battery, the vehicle drive device, and the outside air are used for heating.

[0016] In a first state where there is a heating request and a battery cooling request, the control device controls the opening of the expansion valve to a predetermined opening, and performs cooling of the battery and heating of the air conditioner by heat exchange between the refrigerant and the low-temperature side heat medium that has absorbed the heat of the battery in the cooler. In a second state where there is a heating request and no cooling request, the low-temperature side heat medium does not flow to the heat exchanger of the battery, so the heat of the battery is not used for heating. When switching from the first state to the second state, the control device makes the opening of the expansion valve smaller than the predetermined opening for a predetermined period of time, and then switches from the first state to the second state.

[0017] In the first state, since the battery is cooled, the heat of the battery is absorbed by the low-temperature side heat medium, but in the second state, since the battery is not cooled, the heat of the battery is not absorbed by the low-temperature side heat medium. Therefore, if the first state is switched to the second state, the temperature of the low-temperature side heat medium flowing into the cooler decreases. At this time, even if the opening of the expansion valve is reduced to reduce the flow rate of the refrigerant flowing into the cooler, the flow rate of the refrigerant will temporarily become too large due to the response delay of the expansion valve opening change, and there is a concern that the liquid refrigerant will flow back into the compressor.

[0018] According to this structure, when switching from the first state to the second state, the opening of the expansion valve is made smaller than the specified opening within a specified period, and then the state is switched from the first state to the second state. During the specified period when the opening of the expansion valve is small, the flow rate of the refrigerant flowing into the cooler is reduced and the dryness (quality) of the refrigerant is increased, so that the occurrence of liquid reflux when switching from the first state to the second state can be suppressed.

[0019] Preferably, in the second state, heating is performed by heat exchange between the refrigerant and the low-temperature side heat medium that has absorbed heat from at least one of the vehicle drive device and the outside air in the cooler.

[0020] According to this configuration, in the second state, the air conditioning device can perform heating using heat from at least one of the vehicle drive device and the outside air.

[0021] Preferably, when the control device switches from the first state to the second state, if it is predicted that the temperature of the low-temperature side heat medium flowing into the cooler will drop by a predetermined temperature or more, the control device makes the opening of the expansion valve smaller than a predetermined opening for a predetermined period.

[0022] When switching from the first state to the second state, if it is predicted that the temperature of the low-temperature side heat medium flowing into the cooler will be lower than the specified temperature, there is a high possibility that liquid reflux will not occur. According to this structure, when switching from the first state to the second state, if it is predicted that the temperature of the low-temperature side heat medium flowing into the cooler will drop by more than the specified temperature, the opening of the expansion valve is made smaller than the specified opening within a specified period. In addition, when there is a high possibility that liquid reflux will not occur, the flow rate of the refrigerant flowing into the cooler is not reduced, so that the decline in heating performance can be reduced.

[0023] Preferably, the control device controls the opening of the expansion valve so that the superheat of the refrigerant flowing out of the cooler reaches a target value, and makes the opening of the expansion valve smaller than a predetermined opening by correcting the target value to increase within a predetermined period.

[0024] According to this structure, the opening of the expansion valve is controlled in such a way that the superheat of the refrigerant flowing out of the cooler becomes a target value. Within a specified period, the target value is increased and corrected. As a result, the opening of the expansion valve is made smaller than the specified opening. Therefore, for example, the superheat of the refrigerant flowing into the compressor can be maintained at 1 or more. Liquid reflux can be suppressed.

[0025] Preferably, in the above configuration, the control device is configured to increase the rotation speed of the compressor within a predetermined period.

[0026] According to this configuration, since the rotation speed of the compressor is increased within a specified period, the superheat of the refrigerant flowing out of the cooler can be made to reach a target value while suppressing the decrease in the refrigerant flow rate, thereby reducing the decrease in heating performance before switching from the first state to the second state.

[0027] According to the present disclosure, even when a response delay of the expansion valve occurs, it is possible to suppress the refrigerant flowing into the compressor of the refrigerant circuit from being in a liquid phase or a gas-liquid mixed phase state. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Features, advantages and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like numerals represent like elements, and in which:

[0029] Figure 1 is a diagram showing a schematic structure of a thermal management device for a vehicle according to an embodiment of the present disclosure;

[0030] Figure 2A 2 is a diagram showing the flow of heat during heating of the air conditioning device 2;

[0031] Figure 2B 2 is a diagram showing the flow of heat during heating of the air conditioning device 2;

[0032] Figure 3A 1 is a diagram showing the transition of various parameters when switching from the first mode (loop A) to the second mode (loop B);

[0033] Figure 3B 1 is a diagram showing the transition of various parameters when switching from the first mode (loop A) to the second mode (loop B);

[0034] Figure 4 This is a flowchart showing an example of the circuit switching control process executed by the ECU. DETAILED DESCRIPTION

[0035] Regarding the embodiments of the present disclosure, Figure 1 In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their description will not be repeated.

[0036] Figure 1 2 is a diagram showing a schematic structure of a thermal management device for a vehicle according to this embodiment. Figure 1 As shown, the vehicle 1 is an electric vehicle (xEV) equipped with the thermal management device 10 according to this embodiment. The vehicle 1 is a BEV (battery electric vehicle). However, the vehicle 1 may be an industrial vehicle or another electric vehicle such as a plug-in hybrid vehicle.

[0037] The heat management device 10 includes a heat management circuit 100 and an ECU (Electronic Control Unit) 500. The ECU 500 includes a processor 501 and a memory 502. The processor 501 executes a program stored in the memory 502 to perform various heat management controls in the ECU 500. The ECU 500 corresponds to an example of a "control device" in the present disclosure.

[0038] The thermal management device 10 is configured to perform thermal management of the vehicle 1 using the heat medium of the thermal management circuit 100. The thermal management circuit 100 includes a first circuit 110, a second circuit 120, and a third circuit 130. In addition, the thermal management circuit 100 includes a condenser 140, a refrigerant circuit 150, a cooler 160, a five-way valve 310, and a liquid storage tank (R / T) 320. The five-way valve 310 and the liquid storage tank 320 are shared by the second circuit 120 and the third circuit 130. In addition, the condenser 140, the refrigerant circuit 150, and the cooler 160 are arranged between the first circuit 110 and the second circuit 120. The second circuit 120, the third circuit 130, and the flow path 170a described later are equivalent to an example of the "low temperature side circuit" involved in the present disclosure, and are hereinafter also referred to as the low temperature side circuit.

[0039] The first circuit 110 includes a first flow path for the high-temperature side heat medium to flow. The first circuit 110 includes a pump 111, an electric heating heater 112, a three-way valve 113, a heater core 114, a liquid storage tank (R / T) 115 and a high-temperature radiator 118. The three-way valve 113 switches the path of the high-temperature side heat medium. The pump 111 circulates the high-temperature side heat medium to the first circuit 110. The high-temperature side heat medium exchanges heat with each device when passing through. The heater core 114 is used as a heating source (heat source) of the air conditioning device 2.

[0040] The five-way valve 310 switches the path of the low-temperature side heat medium. The five-way valve 310 has five orifices P1 to P5. The ECU 500 controls the five-way valve 310 in a manner that becomes any one of the first to fifth connection modes. Hereinafter, the orifices P1, P2, P3, P4, and P5 are sometimes abbreviated as "P1", "P2", "P3", "P4", and "P5", respectively.

[0041] In the first connection mode, P1 and P2 are connected, and P3 and P4 are connected, and P5 becomes a non-connected state. In the second connection mode, P1 and P2 are connected, and P4 and P5 are connected, and P3 becomes a non-connected state. In the third connection mode, P1 and P5 are connected, and P3 and P4 are connected, and P2 becomes a non-connected state. In the fourth connection mode, P2 and P4 are connected, and P1 and P3 are connected, and P5 becomes a non-connected state. In the fifth connection mode, P2 and P4 are connected, and P1 and P5 are connected, and P3 becomes a non-connected state.

[0042] The flow paths 120a and 120b are connected to the ports P1 and P2 of the five-way valve 310, respectively. The flow path 120a is a flow path connecting the port P1 and the liquid storage tank 320. The flow path 120b is a flow path connecting the port P2 and the liquid storage tank 320. The second circuit 120 including the flow paths 120a and 120b is formed by connecting P1 and P2 of the five-way valve 310 (for example, the first and second connection modes).

[0043] A pump 121 and a cooler 160 are disposed in the flow path 120a. A battery 200 and an electric battery heater 220 are disposed in the flow path 120b. The pump 121 circulates the low-temperature side heat medium to the second circuit 120. The low-temperature side heat medium exchanges heat with each device when passing through. Therefore, each device has a heat exchanger (or has the function of a heat exchanger). The battery 200 is equivalent to an example of a "battery" in the present disclosure.

[0044] The flow paths 130b and 130a are connected to the ports P3 and P4 of the five-way valve 310, respectively. The flow paths 130b and 130a are flow paths that connect the ports P3 and P4 and the liquid storage tank 320, respectively. The third circuit 130 including the flow paths 130a and 130b is formed by connecting P3 and P4 of the five-way valve 310 (for example, the first and third connection modes).

[0045] The high temperature side heat medium may be a known heat medium for heating, and the low temperature side heat medium may be insulating oil or antifreeze. In addition, in the refrigerant circuit 150 described later, a refrigerant such as hydrofluorocarbon (HFC), ammonia, carbon dioxide, etc. may be used.

[0046] A pump 131, an SPU (Signal Processing Unit) 132, a PCU (Power Control Unit) 133 for electric motors, and an oil cooler (O / C) 135 are arranged in the flow path 130a. The oil cooler 135 cools the transmission axle of the vehicle 1. The pump 131 circulates the low-temperature side heat medium to the third circuit 130. The low-temperature side heat medium exchanges heat with each device when passing through. Therefore, each device is equipped with a heat exchanger (or has the function of a heat exchanger). The PCU 133 for electric motors and the oil cooler 135 are equivalent to an example of the "vehicle drive device" of the present disclosure.

[0047] The flow path 170a is connected to the port P5 of the five-way valve 310. The flow path 170a is a flow path connecting the port P5 and the liquid storage tank 320. The low-temperature radiator 170 is provided in the flow path 170a. The low-temperature radiator 170 functions as a heat exchanger. Through the low-temperature radiator 170, the low-temperature side heat medium flowing in the flow path 170a and the external air perform heat exchange.

[0048] The refrigerant circulates in the refrigerant circuit 150. The refrigerant circuit 150 includes a compressor 151, an electric expansion valve 152, an evaporator 153, an evaporative pressure regulating valve (EPR: Evaporative Pressure Regulator) 154, and an electric expansion valve 155. The compressor 151 compresses and discharges the refrigerant flowing out of the cooler 160. The refrigerant circuit 150 is a refrigeration cycle or a heat pump cycle. The electric expansion valve 155 is equivalent to the "expansion valve" of the present disclosure.

[0049] The evaporator 153 is used as a cooling source of the air conditioning device 2. The condenser 140 is connected to both the first circuit 110 and the refrigerant circuit 150, and functions as a heat exchanger. Through the condenser 140, the high-temperature side heat medium flowing in the first circuit 110 and the refrigerant circulating in the refrigerant circuit 150 perform heat exchange. The cooler 160 is connected to both the refrigerant circuit 150 and the flow path 120a, and functions as a heat exchanger. Through the cooler 160, the refrigerant circulating in the refrigerant circuit 150 and the low-temperature side heat medium flowing in the second circuit 120 perform heat exchange. In this way, the condenser 140, the refrigerant circuit 150 and the cooler 160 are configured to perform heat transfer between the high-temperature side heat medium flowing in the first circuit 110 and the low-temperature side heat medium flowing in the second circuit 120.

[0050] The air conditioning device 2 uses the heat released by the condenser 140 to heat the vehicle interior. When the air conditioning device 2 is heating, the orifices Pa and Pb of the three-way valve 113 are connected, and the high-temperature side heat medium that has absorbed heat in the condenser 140 releases heat in the heater core 114, thereby heating. When heating, the five-way valve 310 is set to, for example, the second connection mode (P1 and P2 are connected, P4 and P5 are connected), and when the battery 200 is being cooled in the low-temperature side circuit, the heat (waste heat) of the battery 200 absorbed by the low-temperature side heat medium is absorbed by the refrigerant in the refrigerant circuit 150 in the cooler 160. The heat of the battery 200 is absorbed by the high-temperature side heat medium in the condenser 140. The heat (waste heat) of the battery 200 is used for heating. This mode of performing heating and cooling of the battery 200 at the same time is called the first mode. The first mode is equivalent to an example of the "first state" of the present disclosure.

[0051] When the air conditioner 2 is heating, if there is no longer a cooling request for the battery 200, the cooling of the battery 200 is stopped. Therefore, if the low temperature side circuit is switched, for example, the five-way valve 310 is set to the third connection mode (P1 and P5 are connected, P3 and P4 are connected), the low temperature side heat medium cannot exchange heat with the battery 200. Therefore, the heat (waste heat) of the battery 200 cannot be used for heating. In this case, when the temperature of the low temperature side heat medium is lower than that of the outside air, the low temperature side heat medium absorbs the heat of the outside air in the low temperature radiator 170. In addition, the low temperature side heat medium absorbs the heat of the motor PCU 133 and the oil cooler 135. This heat is absorbed by the refrigerant of the refrigerant circuit 150 in the cooler 160. In this way, the heat of the outside air, the motor PCU 133 and the oil cooler 135 is used for heating. This mode of heating without cooling the battery 200 is called the second mode. The second mode is equivalent to an example of the "second state" of the present disclosure.

[0052] Figure 2A and Figure 2B It is a diagram showing the flow of heat during heating by the air-conditioning device 2 . Figure 2A The flow of heat during heating in the first mode is shown. In the present embodiment, the state of the heat management circuit 100 is also referred to as circuit A. Figure 2B FIG. 1 shows the heat flow during heating in the second mode. In this embodiment, the state of the heat management circuit 100 is also referred to as circuit B. In the first mode, as Figure 2A As shown in FIG. 1 , the heat (waste heat) of the battery 200 absorbed by the low-temperature side heat medium is absorbed by the refrigerant of the refrigerant circuit 150 in the cooler 160. The heat of the battery 200 is absorbed by the high-temperature side heat medium in the condenser 140 and released from the heater core 114. In this way, the heat (waste heat) of the battery 200 is used for heating. In the second mode, as shown in FIG. Figure 2B As shown, heat from outside air, motor PCU 133 , and oil cooler 135 is released from heater core 114 and utilized for heating.

[0053] When the battery 200 is cooled, the amount of heat generated by the battery 200 is large (the temperature of the battery 200 is high), so in the first mode (loop A), the amount of heat absorbed by the low-temperature side heat medium flowing into the cooler 160 is large. In the second mode (loop B), the amount of heat absorbed by the low-temperature side heat medium from the outside air, the motor PCU 133, and the oil cooler 135 is smaller than in the first mode.

[0054] Figure 3A and Figure 3B It is a diagram showing the transition of various parameters when switching from the first mode (loop A) to the second mode (loop B). Figure 3A The changes of various parameters in the comparative example are shown. Figure 3B FIG. 2 shows the changes of various parameters in this embodiment. Figure 3A and Figure 3B In the figure, from the upper part, the inlet temperature of the low-temperature side heat medium of the cooler 160 (cooler inlet temperature Ti), the superheat target value (SH target value) of the refrigerant (refrigerant circuit 150) after the cooler 160, the opening degree of the electric expansion valve 155 (expansion valve opening degree K), the dryness (quality) of the refrigerant after the cooler 160, the rotation speed of the compressor 151, the heating performance of the air-conditioning device 2, and the refrigerant flow rate Q flowing into the cooler 160 are shown.

[0055] In the comparative example, Figure 3A As shown, at time t1, the first mode (loop A) is switched to the second mode (loop B). If the loop A is switched to the loop B, the cooler inlet temperature Ti drops sharply. The superheat target value (SH target value) after the cooler 160 remains unchanged. Therefore, in order to make the superheat of the refrigerant become the SH target value, the expansion valve opening K is reduced. At this time, due to the responsiveness of the opening change of the electric expansion valve 155, the refrigerant flow rate Q temporarily becomes too large relative to the drop in the cooler inlet temperature Ti (refer to the area circled with a single dot). As a result, the refrigerant cannot fully absorb heat, and the refrigerant flowing into the compressor 151 becomes a liquid phase or a gas-liquid mixed phase state, resulting in liquid reflux.

[0056] exist Figure 3B In the present embodiment shown, from time t0, which is a time before the switching time t1 from circuit A to circuit B by a predetermined time ts, the SH target value is corrected to increase, so that the SH target value increases. The predetermined time ts is equivalent to the "prescribed period" of the present disclosure. At time t0, if the increase of the SH target value begins, the expansion valve opening K decreases. As a result, the refrigerant flow rate Q decreases, and the dryness (quality) of the refrigerant increases. When switching from circuit A to circuit B at time t1, the increase correction of the SH target value is stopped, and the SH target value is restored to the normal value. As a result, the cooler inlet temperature Ti drops sharply and the expansion valve opening K decreases. The refrigerant flow rate Q decreases and the dryness of the refrigerant increases. Therefore, at time t1, even if the cooler inlet temperature Ti drops sharply and the expansion valve opening K decreases, the refrigerant does not become a liquid phase or a gas-liquid mixed phase state. The occurrence of liquid reflux can be suppressed.

[0057] In this embodiment, at time t0, the speed of the compressor 151 is increased, and at time t1, the speed of the compressor 151 is restored to a normal value. If the expansion valve opening K is reduced at time t0, then Figure 3BAs shown by the single-dot chain line, when the refrigerant flow rate Q decreases, the heating performance deteriorates. By increasing the rotational speed of the compressor 151 at time t0, as shown by the solid line, it is possible to suppress the decrease in the refrigerant flow rate Q and also suppress the deterioration of the heating performance.

[0058] Figure 4 FIG. 4 is a flowchart showing an example of the process of the circuit switching control executed by the ECU 500. This flowchart is repeatedly executed at regular intervals when the power switch (ignition switch) of the vehicle 1 is in the ON state. In step (hereinafter, steps will be abbreviated as "S") 10, it is determined whether there is a switching request from the first mode (circuit A) to the second mode (circuit B). The first mode is a mode in which there is a heating requirement for the air conditioner 2 and a cooling requirement for the battery 200. For example, when the five-way valve 310 is set to the second connection mode, heating in the vehicle interior and cooling of the battery 200 are performed. And, when the battery 200 is cooled (the temperature of the battery 200 decreases) and the cooling requirement no longer exists while the heating requirement continues, a switching request is generated to switch from the first mode to the second mode. The second mode is a mode in which there is a heating requirement for the air conditioner 2 and no cooling requirement for the battery 200. For example, the five-way valve 310 is set to the third connection mode, and cooling of the battery 200 is not performed. Heat from the outside air, the motor PCU 133, and the oil cooler 135 is used for heating.

[0059] When there is no switching request from the first mode (circuit A) to the second mode (circuit B), the determination in S10 is negative, and this routine is ended. When there is a switching request from the first mode (circuit A) to the second mode (circuit B), the determination is positive, and the process proceeds to S11.

[0060] In S11, it is determined whether the cooler inlet temperature Ti will drop by a specified temperature S or more when switching from circuit A to circuit B. A temperature sensor 12 provided at the inlet of the cooler 160 of the second circuit 120 detects the temperature of the low-temperature side heat medium (cooler inlet temperature Ti). A temperature sensor 13 provided at the outlet of the oil cooler 135 in the flow path 130a detects the low-temperature side heat medium temperature To. For example, when the first mode (circuit A) is set (the state before switching from circuit A to circuit B), the estimated drop temperature ΔTi (ΔTi = Ti - To) is calculated by subtracting the low-temperature side heat medium temperature To from the cooler inlet temperature Ti. And, when the estimated drop temperature ΔTi is equal to or more than the specified temperature S (ΔTi ≥ S), it is determined that the cooler inlet temperature Ti will drop by the specified temperature S or more, and the process proceeds to S12. When the estimated drop temperature ΔTi is less than the specified temperature S (ΔTi < S), the determination is negative, and the process proceeds to S17. After switching from circuit A to circuit B, this routine is ended.

[0061] In S12, the target SH (target value of superheat of the refrigerant after the cooler 160) is increased. The increase in the target SH can be corrected in a way that the target SH gradually increases, or the target SH can be increased step by step. If the target SH increases, the expansion valve opening K of the electric expansion valve 155 decreases. As a result, the refrigerant flow rate Q flowing into the cooler 160 decreases, and the dryness (quality) of the refrigerant after the cooler 160 increases. Therefore, when switching from circuit A to circuit B in S15 described later, even if the cooler inlet temperature Ti drops sharply and the expansion valve opening K decreases, the refrigerant does not become a liquid phase or a gas-liquid mixed phase state, and the generation of liquid reflux can be suppressed.

[0062] In the next S13, the rotation speed of the compressor 151 is increased. For example, the target rotation speed is corrected to increase gradually. This can suppress the decrease in the refrigerant flow rate Q and suppress the decrease in heating performance.

[0063] In S14, it is determined whether a predetermined time ts has passed since a request for switching from loop A to loop B was generated. The process of S14 is repeated until the predetermined time ts has passed, and if the predetermined time ts has passed, the process proceeds to S15.

[0064] In S15, after switching from loop A to loop B, enter S16. In S16, after returning the target SH and the target speed of the compressor 151 to the values ​​of normal control, the routine ends. The values ​​of the target SH and the target speed of the compressor 151 of normal control are set according to the degree of heating and cooling requirements of the air-conditioning device 2, the degree of temperature increase and cooling requirements of the battery 200, etc. It should be noted that the specified temperature S, the specified time ts, the increase correction amount of the target SH, the increase correction amount of the target speed, etc. are determined in advance by experiments, etc., and stored in the memory 502.

[0065] According to the present embodiment, ECU500 controls the expansion valve opening K of the electric expansion valve 155 to a prescribed opening when there is a heating request and a cooling request for the battery 200 in the first mode (loop A). ​​The refrigerant exchanges heat with the low-temperature side heat medium that has absorbed the heat of the battery 200 in the cooler 160. Thus, the battery 200 is cooled and the vehicle interior is heated. In the second mode (loop B) when there is a heating request and no cooling request, the low-temperature side heat medium does not flow to the heat exchanger of the battery 200, so the heat of the battery 200 is not used for heating. When switching from the first mode to the second mode, ECU500 makes the expansion valve opening K of the electric expansion valve 155 smaller than the prescribed opening within the prescribed time ts, and then switches from the first mode to the second mode. Thus, within the specified time ts, the refrigerant flow rate Q decreases and the quality of the refrigerant increases. Therefore, even if there is a response delay in the opening change of the electric expansion valve 155, the occurrence of liquid reflux when switching from the first mode to the second mode can be suppressed.

[0066] According to the present embodiment, in the second mode (loop B), the refrigerant exchanges heat with the low temperature side heat medium that has absorbed heat from at least one of the motor PCU 133, the oil cooler 135, and the outside air in the cooler 160. Thus, heating is performed. Therefore, the air conditioning device 2 can be heated by using the heat from at least one of the motor PCU 133, the oil cooler 135, and the outside air.

[0067] According to the present embodiment, ECU500 controls the expansion valve opening K of the electric expansion valve 155 in such a manner that the superheat of the refrigerant flowing out of the cooler 160 becomes the SH target value. ECU500 makes the expansion valve opening K smaller than the specified opening by increasing and correcting the SH target value within the specified time ts. ECU500 increases the rotation speed of the compressor 151 within the specified time ts. Since the rotation speed of the compressor is increased within the specified time ts, the superheat of the refrigerant flowing out of the cooler can be increased while suppressing the reduction in the refrigerant flow rate Q, and the decrease in heating performance before switching from the first mode to the second mode can be reduced.

[0068] In the above embodiment, when the ECU 300 switches from the first mode (loop A) to the second mode (loop B), it is predicted that the temperature of the low-temperature side heat medium flowing into the cooler 160 will drop by more than the specified temperature S (affirmative determination in S11). In this case, the ECU 300 makes the expansion valve opening K of the electric expansion valve 155 smaller than the specified opening within the specified time ts. Thus, when switching from loop A to loop B, it is predicted that the temperature of the low-temperature side heat medium flowing into the cooler 160 will be less than the specified temperature S. When there is a high possibility that liquid reflux will not occur, the refrigerant flow rate Q flowing into the cooler is not reduced. This can reduce the decline in heating performance.

[0069] It should be noted that S11 may be omitted and S12 may be executed regardless of the magnitude of the estimated temperature drop ΔTi.

[0070] Furthermore, when a higher heating performance is required from the air conditioner 2, heating may be performed by energizing the heating heater 112 provided in the first circuit 110. It should be noted that the heating heater 112 may not be provided.

[0071] The embodiments disclosed this time should be considered as illustrative in all aspects and not restrictive. The scope of the present disclosure is indicated by the claims rather than the description of the embodiments described above, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A thermal management device for a vehicle, comprising: A refrigerant circuit comprising a compressor for compressing and discharging refrigerant flowing out of a cooler, a condenser for releasing heat of the refrigerant discharged from the compressor, and an expansion valve for decompressing the refrigerant flowing out of the condenser, wherein the cooler exchanges heat between the refrigerant decompressed by the expansion valve and a low-temperature side heat medium; A low temperature side circuit having a heat exchange device that causes the low temperature side heat medium to absorb heat from the battery, heat from the vehicle drive device, and heat from external air; An air conditioning device, utilizing the heat released by the condenser to provide heating; and Control device, The control device is composed of: In a first state in which there is a heating request and a cooling request for the battery, the opening of the expansion valve is controlled to a predetermined opening, and the cooling of the battery and the heating are performed by heat exchange between the refrigerant and the low-temperature side heat medium that has absorbed heat from the battery in the cooler. When switching from the first state to the second state in which the heating request is present and the cooling request is not present, the opening of the expansion valve is made smaller than the predetermined opening for a predetermined period of time, and then the first state is switched to the second state. In the second state, the low-temperature-side heat medium does not flow toward the heat exchanger of the battery.

2. The thermal management device for a vehicle according to claim 1, In the second state, the heating is performed by the refrigerant exchanging heat with the low-temperature-side heat medium that has absorbed heat from at least one of the vehicle drive device and the outside air in the cooler.

3. The thermal management device for a vehicle according to claim 2, When the control device predicts that the temperature of the low-temperature side heat medium flowing into the cooler will drop by a predetermined temperature or more when switching from the first state to the second state, the control device makes the opening of the expansion valve smaller than the predetermined opening for the predetermined period.

4. The thermal management device for a vehicle according to any one of claims 1 to 3, The control device controls the opening degree of the expansion valve so that the superheat degree of the refrigerant flowing out of the cooler reaches a target value. The control device makes the opening degree of the expansion valve smaller than the predetermined opening degree by increasing and correcting the target value during the predetermined period.

5. The thermal management device for a vehicle according to claim 4, The control device is configured to increase the rotation speed of the compressor within the predetermined period.

Images