Air conditioning device for vehicle

Abstract

[Problem] To ensure heating capacity while preventing liquid compression in a compressor even when the outside air temperature is particularly low. [Solution] Provided is an air conditioning device for a vehicle, comprising a refrigerant circuit for circulating a refrigerant, the refrigerant circuit having a compressor, a condenser, an expansion unit, an evaporator, and a gas-liquid separation unit connected in this order through refrigerant piping, the refrigerant circuit comprising: a first bypass flow path through which the refrigerant flows; a flow path through which the refrigerant discharged from the compressor flows into the inlet side of the gas-liquid separation unit; and an internal heat exchanger that exchanges heat between the refrigerant flowing from the gas-liquid separation unit to the compressor and the refrigerant flowing out from the condenser.

Description

Technical Field

[0001] The present invention relates to an air conditioning device for a vehicle. Background Art

[0002] As a vehicle air conditioning device, there is a device using a heat pump type refrigerant circuit. Such a vehicle air conditioning device includes a refrigerant circuit, which has a compressor, a condenser for heat dissipation, an expansion mechanism, and an evaporator for heat absorption. The temperature-regulated air is sent to the vehicle interior through direct heat exchange with the refrigerant in the condenser or evaporator or indirect heat exchange via other heat media.

[0003] In a heat pump type refrigerant circuit, when the outside air is extremely low (eg, -10°C), the density of the refrigerant sucked into the compressor becomes low, so the heating capacity becomes insufficient. Therefore, an auxiliary heat source such as an electric heater is used to supplement the heating capacity. On the other hand, in order to ensure heating capacity without setting up an auxiliary heat source, there is a technology that allows the high-temperature and high-pressure gas refrigerant discharged from the compressor to return to the suction side of the compressor without passing through the heat exchanger, thereby increasing the suction density of the refrigerant independently of the external gas temperature (for example, Patent Document 1). Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 5-223357 Summary of the invention Technical problem to be solved by the invention

[0005] As in the above-mentioned prior art, when the high-temperature and high-pressure gas refrigerant discharged from the compressor returns to the suction side of the compressor, it is difficult to adjust the suction dryness of the compressor. Therefore, a protective measure is required to prevent the compressor from causing liquid compression.

[0006] The present invention aims to solve the above-mentioned problems. That is, the technical problem of the present invention is to ensure heating capacity even when the outside air temperature is particularly low in a vehicle air conditioning device including a heat pump refrigerant circuit, while preventing liquid compression in the compressor. Technical solutions adopted to solve technical problems

[0007] In order to solve the above-mentioned technical problems, one aspect of the present invention has the following structure. That is, a vehicle air-conditioning device in one form of the present invention includes a refrigerant circuit for circulating a refrigerant, wherein the refrigerant circuit is connected in sequence to a compressor, a condenser, an expansion unit, an evaporator and a gas-liquid separation unit through a refrigerant piping, wherein the refrigerant circuit includes: a first bypass flow path, which allows the refrigerant discharged from the compressor to flow into the inlet side of the gas-liquid separation unit; and an internal heat exchanger, which allows the refrigerant from the gas-liquid separation unit to exchange heat with the refrigerant flowing out of the condenser. Effects of the Invention

[0008] According to the vehicle air conditioning apparatus of the present invention including the above-mentioned features, even when the outside air temperature is extremely low, the heating capacity can be ensured, and the liquid compression in the compressor can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is an explanatory diagram showing a schematic configuration of a refrigerant circuit applied to a vehicle air conditioning system according to an embodiment of the present invention. Figure 2 It is an explanatory diagram showing the flow of the refrigerant during the heating operation in the refrigerant circuit of the vehicle air conditioning apparatus according to the embodiment of the present invention. Figure 3 This is an explanatory diagram showing the flow of the refrigerant during the heating operation when the outside air is extremely low temperature in the refrigerant circuit of the vehicle air conditioning apparatus according to the embodiment of the present invention. Figure 4 It is an explanatory diagram showing the flow of the refrigerant during cooling operation in the refrigerant circuit of the vehicle air conditioning apparatus according to the embodiment of the present invention. Figure 5 It is an explanatory diagram showing a schematic structure of a vehicle air conditioning device according to a first embodiment of the present invention. Figure 6 This is an explanatory diagram showing the flow of the refrigerant during the heating operation when the outside air is extremely low temperature in the vehicle air conditioning device according to the first embodiment of the present invention. Figure 7 It is an explanatory diagram showing a schematic structure of a vehicle air conditioning device according to a second embodiment of the present invention. Figure 8 This is an explanatory diagram showing the flow of the refrigerant during the heating operation when the outside air is extremely low temperature in the vehicle air conditioning device according to the second embodiment of the present invention. DETAILED DESCRIPTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same reference numerals in different drawings represent parts with the same functions, and repeated descriptions in the drawings will be appropriately omitted.

[0011] like Figure 1As shown, the refrigerant circuit R of the vehicle air conditioning device applied to the embodiment of the present invention is composed of a compressor 11, a condenser 12, an expansion valve 13, an evaporator 14, a storage tank 15 and an internal heat exchanger 16 connected through refrigerant piping 120A to refrigerant piping 120H, and circulates the refrigerant.

[0012] The refrigerant outlet of the compressor 11 is connected to the refrigerant inlet of the condenser 12 through a refrigerant pipe 120A, and the refrigerant outlet of the condenser 12 is connected to the refrigerant inlet of the high-pressure side flow path 16A of the internal heat exchanger 16 through a refrigerant pipe 120B. The refrigerant outlet of the high-pressure side flow path 16A of the internal heat exchanger 16 is connected to the refrigerant inlet of the evaporator 14 through a refrigerant pipe 120C. The expansion valve 13 is provided on the refrigerant pipe 120C. The refrigerant outlet of the evaporator 14 is connected to the refrigerant inlet of the accumulator 15 through a refrigerant pipe 120D, and the accumulator 15 is connected to the refrigerant inlet of the low-pressure side flow path 16B of the internal heat exchanger 16 through a refrigerant pipe 120E. The refrigerant outlet of the low-pressure side flow path 16B of the internal heat exchanger 16 is connected to the refrigerant inlet of the compressor 11 through a refrigerant pipe 120F.

[0013] The refrigerant pipe 120A connecting the compressor 11 and the condenser 12 is branched at a branch portion 121 provided at the refrigerant outlet of the compressor 11, and the branch portion 121 is connected to one end of the refrigerant pipe 120G. The other end of the refrigerant pipe 120G is connected to a confluence portion 122 provided on the upstream side of the accumulator 15 of the refrigerant pipe 120D. The refrigerant pipe 120G is provided with an electronic expansion valve 18, and by setting the electronic expansion valve 18 to an open state, a first bypass flow path can be formed, which guides the refrigerant discharged from the compressor 11 to the inlet side of the accumulator 15.

[0014] The refrigerant pipe 120B connecting the condenser 12 and the high-pressure side flow path 16A of the internal heat exchanger 16 is branched at a branch portion 123, and the branch portion 123 is connected to one end of the refrigerant pipe 120H. The other end of the refrigerant pipe 120H is connected to a confluence portion 124 provided on the upstream side of the expansion valve 13 of the refrigerant pipe 120C. The refrigerant pipe 120H is provided with a flow regulator 19, and by setting the flow regulator 19 to an open state, a second bypass flow path can be formed, which allows the refrigerant flowing out of the condenser 12 to bypass the high-pressure side flow path 16A of the internal heat exchanger 16 and be introduced into the expansion valve 13.

[0015] In the refrigerant circuit R constructed in this way, the openings of the expansion valve 13, the electronic expansion valve 18, and the flow rate adjustment unit 19 are controlled by a control unit (not shown) according to the air conditioning purpose of the vehicle air conditioning device using the refrigerant circuit R, and the rotation speed of the compressor 11 is controlled to circulate the refrigerant.

[0016] In particular, the control unit controls the flow regulating unit 19 as follows: based on the state (pressure, temperature, dryness or superheat) of the refrigerant discharged from the compressor 11 or the state (pressure, temperature, dryness or superheat) of the refrigerant at the outlet of the storage tank 15, the opening degree thereof is appropriately adjusted between fully closed and fully open.

[0017] For example, the control unit estimates the superheat based on the state (pressure, temperature, etc.) of the refrigerant at the outlet of the compressor 11, that is, the state of the refrigerant discharged from the compressor 11, and adjusts and controls the opening of the flow regulating unit 19 based on the estimated superheat, thereby adjusting the flow rate of the refrigerant flowing through the second bypass flow path.

[0018] When the superheat degree is greater than a predetermined threshold value, liquid compression is unlikely to occur, but when it is less than the threshold value, it is estimated that the possibility of liquid compression occurring is high. Therefore, the flow rate of the refrigerant flowing through the second bypass flow path is adjusted by the flow rate adjustment unit 19 so that the superheat degree is greater than the threshold value, thereby adjusting the flow rate of the refrigerant flowing through the high-pressure side flow path 16A of the internal heat exchanger 16. In this way, the heat exchange amount in the internal heat exchanger 16 can be controlled.

[0019] In addition, the suction dryness (e.g., 0.95) of the compressor 11 and the adiabatic compression efficiency of the compressor 11 under normal conditions are determined based on the state of the refrigerant on the discharge side of the compressor 11 and the state of the refrigerant on the suction side of the compressor 11, i.e., the outlet of the storage tank 15 (pressure, temperature, etc.), so the discharge temperature of the compressor 11 under normal conditions can be obtained. In this way, it can be determined whether the compressor 11 is operating normally, i.e., whether liquid compression occurs.

[0020] Therefore, the control unit estimates the suction dryness of the compressor 11 based on the state of the refrigerant discharged from the compressor 11 and the state of the refrigerant at the outlet of the storage tank 15, and adjusts the flow rate of the refrigerant flowing through the second bypass flow path based on the estimated suction dryness, thereby adjusting the flow rate of the refrigerant flowing through the high-pressure side flow path 16A of the internal heat exchanger 16. In this way, the heat exchange amount in the internal heat exchanger 16 can be controlled.

[0021] In addition, Figures 2 to 4 In the figure, solid lines indicate refrigerant pipes through which high-pressure refrigerant flows, dashed lines indicate refrigerant pipes through which low-pressure refrigerant flows, and dotted lines indicate refrigerant pipes through which no refrigerant flows.

[0022] (Refrigerant flow during heating operation) For example, when the vehicle air conditioner is immediately started and the heating operation is performed, the refrigerant circulates in the refrigerant circuit R as follows. like Figure 2As shown, in the refrigerant circuit R, the first bypass flow path (refrigerant piping 120G) is not used, that is, the electronic expansion valve 18 is set to a fully closed state, and the flow regulating unit 19 is set to a fully open state, and the second bypass flow path (refrigerant piping 120H) is used. The high-pressure gas refrigerant discharged from the compressor 11 exchanges heat with the heat medium of the high-temperature heat exchanger 21 provided integrally with the flow condenser 12 in the condenser 12 to dissipate heat and liquefy and condense to become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flowing out of the condenser 12 is decompressed and expanded by the expansion valve 13 to become a low-pressure refrigerant, and flows into the evaporator 14.

[0023] The low-pressure refrigerant flowing into the evaporator 14 exchanges heat with the heat medium of the low-temperature heat exchanger 31 that is integrally provided with the evaporator 14, thereby evaporating, becoming a gas refrigerant and flowing out of the evaporator 14, and flowing to the low-pressure side flow path 16B of the internal heat exchanger 16 via the accumulator 15. At this time, the flow regulator 19 is in a fully open state, so the high-pressure refrigerant flowing through the condenser 12 does not flow to the high-pressure side flow path 16A of the internal heat exchanger 16. Therefore, the refrigerant flowing out of the accumulator 15 circulates in the low-pressure side flow path 16B of the internal heat exchanger 16 without heat exchange, and returns to the compressor 11.

[0024] (Flow of refrigerant during heating operation when the outside air is extremely low temperature) On the other hand, for example, in heating operation when the outside air is extremely low temperature, the refrigerant circulates in the refrigerant circuit R as follows. like Figure 3 As shown, in the refrigerant circuit R, the electronic expansion valve 18 is set to an open state and the first bypass flow path (refrigerant piping 120G) is used, and the flow regulator 19 is set to a fully closed state without using the second bypass flow path (refrigerant piping 120H), and heat exchange between the high-pressure refrigerant and the low-pressure refrigerant is performed in the internal heat exchanger 16. In addition, as described above, the flow regulator 19 adjusts the opening degree based on the state of the refrigerant at the outlet of the compressor 11 or the outlet of the storage tank 15, so it is not necessary to limit the fully closed state.

[0025] Thus, a part of the high-pressure gas refrigerant discharged from the compressor 11 exchanges heat with the heat medium of the high-temperature heat exchanger 21 provided integrally with the condenser 12 in the condenser 12, thereby dissipating heat and liquefying and condensing to become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flowing out of the condenser 12 flows through the high-pressure side flow path 16A of the internal heat exchanger 16, and exchanges heat with the low-pressure side refrigerant flowing through the low-pressure side flow path 16B.

[0026] The refrigerant flowing out of the high-pressure side flow path 16A of the internal heat exchanger 16 is decompressed and expanded by the expansion valve 13 to become a low-pressure refrigerant, and flows into the evaporator 14. The low-pressure refrigerant flowing out of the evaporator 14 flows out of the evaporator 14 without exchanging heat with the heat medium of the low-temperature heat exchanger 31 that flows through and is integrally provided with the evaporator 14, and flows into the storage tank 15 together with the refrigerant that flows into the confluence portion 122 from the first bypass flow path.

[0027] In addition, the remaining part of the high-pressure gas refrigerant discharged from the compressor 11 flows in the first bypass flow path and is decompressed at the electronic expansion valve 18, and then flows into the storage tank 15 after merging with the refrigerant flowing out of the evaporator 14 at the merging portion 122. The low-pressure refrigerant separated from the gas and liquid in the storage tank 15 flows through the low-pressure side flow path 16B of the internal heat exchanger 16 and exchanges heat with the high-pressure refrigerant flowing through the high-pressure side flow path 16A, and returns to the compressor 11.

[0028] (Refrigerant flow during cooling operation) Furthermore, for example, during cooling operation, the refrigerant circulates in the refrigerant circuit R as follows. like Figure 4 As shown, in the refrigerant circuit R, the electronic expansion valve 18 is set to a fully closed state without using the first bypass flow path (refrigerant piping 120G), the flow regulating unit 19 is set to a fully closed state without using the second bypass flow path (refrigerant piping 120H), and heat exchange between the high-pressure refrigerant and the low-pressure refrigerant is performed in the internal heat exchanger 16.

[0029] Thus, the high-pressure gas refrigerant discharged from the compressor 11 exchanges heat with the heat medium of the high-temperature heat exchanger 21 provided integrally with the condenser 12 in the condenser 12, thereby dissipating heat and liquefying and condensing to become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flowing out of the condenser 12 flows through the high-pressure side flow path 16A of the internal heat exchanger 16, and exchanges heat with the low-pressure side refrigerant flowing through the low-pressure side flow path 16B.

[0030] The refrigerant flowing out of the high-pressure side flow path 16A of the internal heat exchanger 16 is decompressed and expanded by the expansion valve 13, becomes a low-pressure refrigerant, and flows into the evaporator 14. The low-pressure refrigerant flowing out of the evaporator 14 exchanges heat with the heat medium of the low-temperature heat exchanger 31 that is integrally provided with the evaporator 14, thereby evaporating, becomes a gas refrigerant, flows out of the evaporator 14, and flows into the storage tank 15. The low-pressure refrigerant separated by gas and liquid in the storage tank 15 flows through the low-pressure side flow path 16B of the internal heat exchanger 16, exchanges heat with the high-pressure refrigerant flowing through the high-pressure side flow path 16A, and returns to the compressor 11.

[0031] According to the refrigerant circuit configured in this way, during heating operation when the outside air is extremely low temperature, the first bypass flow path is used to return the high-temperature and high-pressure refrigerant discharged from the compressor 11 to the upstream side of the storage tank 15 without flowing through other heat exchangers, thereby increasing the density of the refrigerant sucked into the compressor 11. Therefore, the heating capacity of the condenser 12 can be ensured without relying on the outside air, and the heating capacity can be ensured.

[0032] Furthermore, by causing the refrigerant flowing out of the accumulator 15 to flow into the low-pressure side flow path 16B of the internal heat exchanger 16 , the state of the refrigerant can be stabilized, and liquid compression in the compressor 11 can be prevented. That is, when the second bypass flow path is used and heat exchange is not performed with the refrigerant flowing through the low-temperature side flow path 16B in the internal heat exchanger 16, the low-pressure side flow path 16B of the internal heat exchanger 16 can be made into a mixing chamber of liquid refrigerant and gaseous refrigerant. Therefore, the state of the refrigerant can be stabilized and liquid compression in the compressor 11 can be suppressed. On the other hand, when the refrigerant flows into the high-pressure flow path 16A and exchanges heat with the refrigerant flowing in the low-pressure flow path 16B, the state of the refrigerant can be further stabilized by the heat exchange, and liquid compression can be further prevented.

[0033] In addition, the sign of liquid compression is monitored based on the discharge temperature of the compressor 11. When the sign of liquid compression is observed, the flow rate regulating unit 19 is controlled so as to increase the amount of refrigerant flowing into the high-pressure side flow path 16A of the internal heat exchanger 16. When the sign of liquid compression is not observed, the flow rate regulating unit 19 is controlled so as to decrease the amount of refrigerant flowing into the high-pressure side flow path 16A of the internal heat exchanger 16, thereby regulating the flow rate of refrigerant flowing into the second bypass flow path and the high-pressure side flow path 16A of the internal heat exchanger 16. In this way, liquid compression in the compressor 11 can be more reliably prevented without reducing the air conditioning efficiency.

[0034] exist Figures 2 to 4 In the illustrated example, the flow rate adjustment unit 19 is described as being fully closed or fully opened, but the flow rate adjustment unit 19 may be adjusted appropriately in order to improve air conditioning efficiency. For example, when the refrigerant flow rate flowing into the high-pressure side flow path 16A of the internal heat exchanger 16 is small, the suction density of the refrigerant in the compressor 11 becomes large, the discharge temperature of the compressor 11 becomes low, and the inlet temperature of the expansion valve 13 becomes high. On the other hand, when the refrigerant flow rate flowing into the high-pressure side flow path 16A of the internal heat exchanger 16 is large, the suction density of the refrigerant in the compressor 11 becomes small, the discharge temperature of the compressor 11 becomes high, and the inlet temperature of the expansion valve 13 becomes low.

[0035] In the case of heating operation, when the heating capacity and air conditioning efficiency are improved, it is determined which of the refrigerant suction density in the compressor 11 and the refrigerant discharge temperature in the compressor 11 contributes more, and the flow rate regulator 19 is controlled.

[0036] Furthermore, in the case of cooling operation, when the cooling capacity and air conditioning efficiency are to be improved, it is determined which of the refrigerant suction density in the compressor 11 and the inlet temperature of the expansion valve 13 contributes more, and the flow rate regulator 19 is controlled.

[0037] When the above-mentioned refrigerant circuit R is applied to a vehicle air-conditioning device, for example, it can be configured so that the refrigerant in the refrigerant circuit directly exchanges heat with the air supplied to the vehicle interior (Example 1), or it can be configured so that the refrigerant in the refrigerant circuit exchanges heat with other heat medium and then exchanges heat with the air supplied to the vehicle interior (Example 2).

[0038] (Example 1) like Figure 5 As shown, the vehicle air conditioning device 101 is configured to directly exchange heat between the refrigerant in the refrigerant circuit and the air supplied to the vehicle interior, and includes: a refrigerant circuit R1 as a heat source; and an air conditioning unit 80, which supplies air whose temperature is adjusted by heat exchange with the refrigerant to the vehicle interior.

[0039] exist Figure 5 In the example of , the condenser 12 and the evaporator 14 of the refrigerant circuit R1 are arranged in the air flow path 84 of the air conditioning unit 80. The condenser 12 includes an air heat exchanger integrally provided with the condenser 12, and becomes an indoor heat exchanger 4, which heats the air supplied to the vehicle interior by dissipating the high-temperature and high-pressure refrigerant discharged from the compressor 11. The evaporator 14 includes an air heat exchanger integrally provided with the evaporator 14, and becomes a heat absorber 9, which cools the air supplied to the vehicle interior by allowing the refrigerant to absorb heat from the inside and outside of the vehicle interior during cooling and dehumidification.

[0040] In addition, Figure 5 The refrigerant circuit R1 is provided with: an outdoor expansion valve 6, which decompresses and expands the refrigerant during heating; an outdoor heat exchanger 7, which is used to perform heat exchange between the refrigerant and the external air, so as to act as a radiator for the refrigerant to dissipate heat during cooling, and as an evaporator for the refrigerant to absorb heat during heating; a refrigerant-heat medium heat exchanger 64, which performs heat exchange between the refrigerant in the refrigerant circuit R1 and other heat media; and an expansion valve 72, which decompresses the refrigerant flowing into the refrigerant-heat medium heat exchanger 64.

[0041] In the vehicle air conditioning device 101 configured as above, when the first bypass flow path is used for heating operation at low outside temperature, the control unit (not shown) closes the outdoor expansion valve 6, the expansion valve 13, and the electromagnetic valve 23, opens the electromagnetic valve 22 and the expansion valve 72, and opens the electronic expansion valve 18. Thus, the first bypass flow path is configured. Figure 6 In addition, at this time, the indoor air blower 87 is operated to introduce air from the suction port 83, and the ratio of the air blown from the indoor air blower 87 to the indoor heat exchanger 4 is adjusted by the air mixing damper 89.

[0042] like Figure 6 As shown, part of the refrigerant discharged from the compressor 11 flows into the indoor heat exchanger 4. The high-temperature and high-pressure gas refrigerant flowing into the indoor heat exchanger 4 exchanges heat with the air in the air flow path 84, and the air in the air flow path 84 is heated by the refrigerant, and the heated air is blown into the vehicle interior from the blow-out port to heat the vehicle. The refrigerant after heat exchange in the indoor heat exchanger 4 loses heat to the air and is cooled and condensed.

[0043] After the condensed refrigerant flows out of the indoor heat exchanger 4, a part of it flows to the high-pressure side flow path 16A of the internal heat exchanger 16, and the rest flows to the second bypass flow path. The refrigerant flowing through the high-pressure side flow path 16A exchanges heat with the refrigerant flowing through the low-pressure side flow path 16B and flows toward the confluence portion 124. The refrigerant flowing through the second bypass flow path and passing through the flow regulating portion 19 merges with the refrigerant flowing through the high-pressure side flow path 16A of the internal heat exchanger 16 at the confluence portion 124, passes through the expansion valve 72, and flows through the refrigerant heat medium heat exchanger 64. The refrigerant expands in the expansion valve 72 to become low temperature and low pressure, flows through the refrigerant heat medium heat exchanger 64 without exchanging heat with the heat medium, and flows into the storage tank 15.

[0044] On the other hand, the high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows in the first bypass flow path, is expanded by the electronic expansion valve 18, and flows into the accumulator 15 again. That is, the refrigerant that has been liquefied through the indoor heat exchanger 4, the high-pressure side flow path 16A of the internal heat exchanger, and the expansion valve 72, and the refrigerant that has been compressed by the compressor 11 and expanded by the electronic expansion valve 18 flow into the accumulator 15. The refrigerant that has flowed into the accumulator 15 is separated into gas and liquid, and is sucked into the compressor 11 as a gas refrigerant while flowing through the low-pressure side flow path 16B of the internal heat exchanger 16, and the above cycle is repeated.

[0045] (Example 2) like Figure 7As shown, the vehicle air conditioning device 102 is constructed as follows: after the refrigerant in the refrigerant circuit exchanges heat with other heat media, the heat medium is heat exchanged with the air supplied to the vehicle interior, including: a refrigerant circuit R2, which serves as a heat source; a heat medium circuit 10, in which a heat medium circulates, and the temperature of the heat medium is managed by heat exchange with the refrigerant; and an air conditioning unit 80, which supplies air to the vehicle interior, and the temperature of the air is adjusted by the heat medium circulating in the heat medium circuit 10.

[0046] The heat medium circuit 10 includes a high-temperature heat medium flow path 20 , a low-temperature heat medium flow path 30 , a temperature adjustment target heat medium flow path 40 , a tank 50 , a first flow path switching unit V1 , a second flow path switching unit V2 , and a third flow path switching unit V3 .

[0047] The high-temperature heat medium flow path 20 includes a high-temperature heat exchanger 21 as a refrigerant heat medium heat exchanger, and the high-temperature heat exchanger 21 is integrated with the condenser 12 in the refrigerant circuit R2 to perform heat exchange between the heat medium and the refrigerant. In the high-temperature heat medium flow path 20, the heat medium pumped by the first pump P1 becomes high temperature and circulates due to the heat dissipation of the refrigerant in the condenser 12 in the refrigerant circuit R2 while circulating through the high-temperature heat exchanger 21.

[0048] The low-temperature heat medium flow path 30 includes a low-temperature heat exchanger 31, which is integrated with the evaporator 14 in the refrigerant circuit R2 and performs heat exchange between the heat medium and the refrigerant. The heat medium pumped by the second pump P2 becomes low-temperature and circulates while circulating through the low-temperature heat exchanger 31 due to the heat absorption of the refrigerant in the evaporator 14 in the refrigerant circuit R2.

[0049] The temperature-adjustment target heat medium flow path 40 includes: a battery heat exchanger 41 that adjusts the temperature of the battery in the electric vehicle; a motor heat exchanger 42 that adjusts the temperature of the travel motor; an inverter heat exchanger 43 that adjusts the temperature of the inverter; a PCU heat exchanger 44 that adjusts the temperature of the power control unit; and an outdoor heat exchanger 45. In the temperature-adjustment target heat medium flow path 40, the heat medium is pressure-fed by the third pump P3.

[0050] The tank 50 includes an inlet 52 connected to the high-temperature heat medium flow path 20 , an inlet 54 connected to the temperature adjustment target heat medium flow path 40 , and an outlet 53 connected to the low-temperature heat medium flow path 30 . In the high-temperature heat medium flow path 20, a connection portion 28 connected to the inlet 52 is provided on the heat medium upstream side of the first pump P1. In the temperature control target heat medium flow path 40, a connection portion 48 connected to the inlet 54 is provided on the heat medium downstream side of each temperature control target heat exchanger. In the low-temperature heat medium flow path 30, a connection portion 38 connected to the outlet 53 is provided on the heat medium upstream side of the second pump P2.

[0051] That is, Figure 7 As shown, the tank 50 is connected to the upstream side of the first pump P1 in the high-temperature heat medium flow path 20 through the inlet 52, is connected to the heat medium downstream side of the motor heat exchanger 42 in the temperature adjustment object heat medium flow path 40 through the inlet 54, and is connected to the heat medium upstream side of the second pump P2 in the low-temperature heat medium flow path 30 through the outlet 53.

[0052] In addition, a pressure relief valve 57 is provided on the path from the connection portion 28 to the inlet 52 of the tank 50. As a result, the heat medium expands due to the increase in the temperature of the heat medium circulating in the high-temperature heat medium flow path 20, and the amount of heat medium increases relative to the circuit capacity of the high-temperature heat medium flow path 20. In this case, the pressure relief valve 57 is opened, and the heat medium flows from the high-temperature heat medium flow path 20 into the tank 50 through the inlet 52.

[0053] Similarly, a pressure relief valve 58 is provided on the path from the connection portion 48 to the inlet 54 of the tank 50. As a result, the heat medium expands due to the increase in the temperature of the heat medium circulating in the temperature control target heat medium flow path 40, and the amount of heat medium increases relative to the circuit capacity of the temperature control target heat medium flow path 40. In this case, the pressure relief valve 58 is opened, and the heat medium flows from the temperature control target heat medium flow path 40 through the inlet 54 into the tank 50.

[0054] On the other hand, when the temperature of the heat medium circulating in the low-temperature heat medium flow path 30 decreases and the heat medium contracts, the heat medium stored in the tank 50 flows out from the outflow port 53 and flows into the low-temperature heat medium flow path 30 through the connection portion 38 .

[0055] In addition, as the heat medium circulating in the heat medium circuit 10, water without additives, water mixed with additives such as antifreeze and preservatives, or even liquid heat medium such as oil can be used.

[0056] The air conditioning unit 80 includes: an air intake port 83, which introduces air (external air or internal air); an air flow path 84, which circulates the air sucked in by the air intake port 83; and a first heat exchanger 81 and a second heat exchanger 82, which are arranged in the air flow path 84 and provide the heat medium flow circulating in the heat medium circuit 10.

[0057] In the air conditioning unit 80 , air introduced from the air inlet 83 into the air flow path 84 is ventilated toward the first heat exchanger 81 and the second heat exchanger 82 , and the air having its temperature adjusted by heat exchange with the heat medium in the first heat exchanger 81 and the second heat exchanger 82 is supplied into the vehicle interior.

[0058] In the vehicle air conditioning device 102 configured in this way, the flow rate of the refrigerant to the first bypass flow path and the second bypass flow path is controlled by adjusting the opening of the flow rate adjustment unit 19 and the electronic expansion valve 18 by a control unit (not shown). In addition, in the heat medium circuit 10, by controlling the first flow path switching unit V1, the second flow path switching unit V2, and the third flow path switching unit V3, the connection state of the high-temperature heat medium flow path 20, the low-temperature heat medium flow path 30, and the temperature adjustment target heat medium flow path 40 of the heat medium circuit 10 can be appropriately switched.

[0059] Next, in the vehicle air conditioning device 102 thus constructed, the control unit (not shown) appropriately controls the rotation speed of the compressor 11, and adjusts the air supplied to the vehicle interior to the target temperature by utilizing the heat dissipation of the condenser 12 and the heat absorption of the evaporator 14, thereby performing air conditioning in the vehicle interior. In particular, in the case of heating operation at a low outside temperature, in the refrigerant circuit R2, the electronic expansion valve 18 is set to an open state to form a first bypass flow path, and the flow rate adjustment unit 19 is set to a closed state to block the second bypass flow path. In the refrigerant circuit R2, the refrigerant and Figure 3 The refrigerant circuit R circulates in the same manner.

[0060] That is, in the refrigerant circuit R2, the electronic expansion valve 18 is also set to a fully open state and the first bypass flow path is used, and the flow regulating unit 19 is set to a fully closed state without using the second bypass flow path, and heat exchange between the high-pressure refrigerant and the low-pressure refrigerant is performed in the internal heat exchanger 16.

[0061] Thus, a part of the high-pressure gas refrigerant discharged from the compressor 11 exchanges heat with the heat medium of the high-temperature heat exchanger 21 provided integrally with the condenser 12 in the condenser 12, thereby dissipating heat and liquefying and condensing to become a high-pressure liquid refrigerant. The high-pressure liquid refrigerant flowing out of the condenser 12 flows through the high-pressure side flow path 16A of the internal heat exchanger 16, and exchanges heat with the low-pressure side refrigerant flowing through the low-pressure side flow path 16B.

[0062] The refrigerant flowing out of the high-pressure side flow path 16A of the internal heat exchanger 16 is decompressed and expanded by the expansion valve 13 to become a low-pressure refrigerant, and flows into the evaporator 14. The low-pressure refrigerant flowing out of the evaporator 14 flows out of the evaporator 14 without exchanging heat with the heat medium of the low-temperature heat exchanger 31 that flows through and is integrally provided with the evaporator 14, and flows into the storage tank 15 together with the refrigerant that flows into the confluence portion 122 from the first bypass flow path.

[0063] In addition, the remaining part of the high-pressure gas refrigerant discharged from the compressor 11 flows in the first bypass flow path and is decompressed at the electronic expansion valve 18, and then merges with the refrigerant flowing out of the evaporator 14 at the confluence portion 122 and flows into the storage tank 15. The low-pressure refrigerant separated from the gas and liquid in the storage tank 15 flows through the low-pressure side flow path 16B of the internal heat exchanger 16 and exchanges heat with the high-pressure refrigerant flowing through the high-pressure side flow path 16A, and returns to the compressor 11.

[0064] On the other hand, in the heat medium circuit 10, the heat medium circulates as follows ( Figure 8 ).

[0065] exist Figure 8 In the figure, regarding the flow of heat medium, black solid lines represent pipes where high-temperature heat medium circulates, double-dashed lines represent pipes where heat medium circulates in a temperature zone between high and low temperatures, and dotted lines represent pipes where heat medium does not circulate. The control unit controls the first flow switching unit V1 , the second flow switching unit V2 , and the third flow switching unit V3 to circulate the heat medium in the heat medium circuit 10 as follows.

[0066] The heat medium heated by circulating through the high-temperature heat exchanger 21 is circulated to the high-temperature heat medium flow path 20. That is, the heat medium heated by circulating through the high-temperature heat exchanger 21 flows into the second heat exchanger 82 through the first flow path switching part V1, exchanges heat with the air of the circulation air conditioning unit 80, and then flows into the first heat exchanger 81 through the first flow path switching part V1, and exchanges heat with the air of the circulation air conditioning unit 80. The heat medium flowing out of the first heat exchanger 81 passes through the first flow path switching part V1 and the third flow path switching part V3 and returns to the high-temperature heat exchanger 21 through the first pump P1, and the above cycle is repeated. In this way, the vehicle interior can be heated.

[0067] In the temperature adjustment object heat medium flow path 40, the battery heat exchanger 41 is connected to the motor heat exchanger 42, the inverter heat exchanger 43 and the PCU heat exchanger 44 via the second flow path switching unit V2, and the heat medium is pressurized and circulated to the battery heat exchanger 41, the motor heat exchanger 42, the inverter heat exchanger 43 and the PCU heat exchanger 44 by the third pump P3, thereby adjusting the temperature of each vehicle-mounted equipment.

[0068] In addition, as described above, the control unit controls the first flow path switching unit V1 to be switched so that the heat medium flowing through the second heat exchanger 82 also flows through the first heat exchanger 81. That is, since the first flow path switching unit V1 can be switched so that the heated or cooled heat medium flows to both of the plurality of first heat exchangers 81 and the second heat exchanger 82 included in the air conditioning unit 80, the air conditioning capacity when the heating mode is executed or the cooling mode is executed can be improved.

[0069] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the specific structure is not limited to these embodiments or examples, and even if there are changes in the design that do not deviate from the scope of the purpose of the present invention, they are also included in the present invention. In addition, as long as there are no special contradictions or problems in the purpose and structure of the above-mentioned embodiments, they can be combined using mutual technologies. Explanation of symbols

[0070] 4: Indoor heat exchanger, 6: Outdoor expansion valve, 7: Outdoor heat exchanger, 9: Heat absorber 10: Heat medium circuit, 11: Compressor, 12: Condenser, 13: Expansion valve, 14: Evaporator, 15: Storage tank, 16: Internal heat exchanger, 16A: High-pressure side flow path, 16B: Low-pressure side flow path 18: Electronic expansion valve, 19: Flow rate adjustment unit, 20: High-temperature heat medium flow path, 21: High-temperature heat exchanger 22, 23: Solenoid valve, 30: Low-temperature heat medium flow path, 31: Low-temperature heat exchanger 40: Temperature adjustment target heat medium flow path, 64: Refrigerant heat medium heat exchanger, 72: Expansion valve, 80: Air conditioning unit 101, 102: Car air conditioning device R: refrigerant circuit, R1: refrigerant circuit, R2: refrigerant circuit.

Claims

1. A vehicle air conditioning device, The invention comprises a refrigerant circuit for circulating a refrigerant, wherein the refrigerant circuit sequentially connects a compressor, a condenser, an expansion unit, an evaporator and a gas-liquid separation unit through a refrigerant pipe, and is characterized in that: The refrigerant circuit comprises: a first bypass flow path that allows the refrigerant discharged from the compressor to flow into the inlet side of the gas-liquid separation unit; and The internal heat exchanger exchanges heat between the refrigerant flowing from the gas-liquid separation unit to the compressor and the refrigerant flowing out of the condenser.

2. The vehicle air conditioning device according to claim 1, characterized in that: A second bypass flow path is included, which allows the refrigerant flowing out of the condenser to bypass the internal heat exchanger and flow into the evaporator.

3. The vehicle air conditioning device according to claim 2, characterized in that: The second bypass flow passage includes a flow rate adjustment unit that adjusts a flow rate of the refrigerant flowing through the second bypass flow passage.

4. The vehicle air conditioning device according to claim 3, characterized in that: The flow rate adjustment unit adjusts a flow rate of the refrigerant flowing through the second bypass flow path based on a superheat degree estimated from a pressure and a temperature of the refrigerant discharged from the compressor.

5. The vehicle air conditioning device according to claim 4, characterized in that: The flow rate regulator reduces a flow rate of the refrigerant flowing into the second bypass flow path when the degree of superheat is equal to or lower than a threshold value.

6. The vehicle air conditioning device according to claim 3, characterized in that: The flow rate adjustment unit adjusts a flow rate of the refrigerant flowing through the second bypass flow path based on a suction dryness estimated from a temperature of the refrigerant discharged from the compressor.

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