Vehicle air conditioning device

Abstract

In a vehicle air conditioning device with a refrigerant circuit in which switching takes place between heat absorption heating operation and hot gas heating operation, the accumulation of refrigerant in an external heat exchanger is prevented by providing an intermediate operating mode and thus ensures sufficient heating capacity.The vehicle air conditioning device comprises a control device that controls a refrigerant circuit and an air conditioning unit, wherein the refrigerant circuit has a hot gas bypass, wherein the control device can perform a hot gas heating operation in which the refrigerant in the external heat exchanger section does not absorb heat and a part of the refrigerant compressed in the compressor releases heat in the internal heat exchanger section to heat a passenger compartment, and a heat absorption heating operation in which the refrigerant absorbs heat at the external heat exchanger section, wherein during the hot gas heating operation, refrigerant is allowed to flow through the external heat exchanger section while heat exchange at the external heat exchanger section is prevented.

Description

TECHNICAL FIELD

[0001] The present invention relates to a vehicle air conditioning device. STATE OF THE ART

[0002] As an air conditioning device of electric vehicles (EVs) that do not have a fuel combustion system of an internal combustion engine or the like for heat supply, or vehicles in which the heat quantity of the fuel combustion system serving as a heat source is small, an air conditioning device that uses a heat pump (refrigerant cycle) for heat supply is known.

[0003] The air conditioning system that uses a heat pump uses an external heat exchanger as a heat sink during heating operation, thus obtaining heat from the outside air. At extremely low outside air temperatures, heat absorption from the outside air becomes difficult, resulting in a significant reduction in heating efficiency. On the other hand, if heat is supplied using an electric heater such as a PTC heater, battery power consumption increases significantly. This can negatively impact the range in electric vehicles and the like, and also increases the manufacturing cost of the air conditioning system due to the inclusion of the PTC heater.

[0004] Hot gas heating, which utilizes high-temperature, high-pressure refrigerant discharged from a compressor in the refrigerant cycle, is a form of heating without heat absorption and is therefore expected to be effective even in extremely low-temperature environments. In hot gas heating, an internal heat exchanger of the vehicle air conditioning system serves as a heat sink (internal condenser), to which the high-temperature, high-pressure refrigerant discharged from the compressor is directly supplied. The refrigerant discharged from the heat sink is returned to the compressor via an accumulator rather than through an external heat exchanger (see Patent Document 1 below). LIST OF REFERENCE DOCUMENTSPATENT DOCUMENT

[0005] Patent Document 1: JP 2014-196017 A SUMMARY OF THE INVENTION OBJECT OF THE INVENTION

[0006] A vehicle air conditioning device capable of performing hot gas heating performs hot gas heating in situations where heat absorption from the outside air, etc. is not possible, and performs heat absorption heating in situations where heat absorption from the outside air, etc. is possible, by switching between a refrigerant flow path in which hot gas heating is performed and a refrigerant flow path in which regular heat absorption heating is performed.

[0007] In the hot gas heating operation, the refrigerant flow path is switched to a refrigerant flow path in which the refrigerant does not flow to an external heat exchanger. In the refrigerant flow path during the hot gas heating operation, not only the high-pressure side refrigerant flow path but also the low-pressure side refrigerant flow path after the pressure reduction is higher than the refrigerant flow path on the outlet side of the external heat exchanger, so that a situation may arise in which there is no longer a refrigerant flow path through which the refrigerant that flowed in the external heat exchanger during the heat absorption heating flows out.

[0008] If the refrigerant flowing through the external heat exchanger accumulates during hot gas heating operation, the amount of refrigerant used in hot gas heating operation decreases. When this happens, the refrigerant flow rate drawn into the compressor during hot gas heating operation can no longer be increased, so the refrigerant pressure can no longer be raised to the required level, resulting in the problem of insufficient heating capacity.

[0009] The present invention is based on the object of counteracting these problems. One of the objects of the present invention is therefore to prevent the accumulation of refrigerant in the external heat exchanger in a vehicle air conditioning device with a refrigerant circuit that switches between heat absorption heating mode and hot gas heating mode, thus ensuring sufficient heating performance. SOLUTION OF THE TASKS

[0010] To achieve these objects, the present invention is provided with the following configuration.

[0011] A vehicle air conditioning device comprising a refrigerant circuit with a compressor, an internal heat exchanger section, and an external heat exchanger section, an air conditioning unit in the interior of which the internal heat exchanger section is arranged, and a control device that controls the refrigerant circuit and the air conditioning unit, wherein the refrigerant circuit has a hot gas bypass that reduces the pressure of at least a portion of the refrigerant compressed in the compressor and returns it to the compressor without passing through the internal heat exchanger section and the external heat exchanger section, wherein the control device can perform a hot gas heating operation, in which the refrigerant in the external heat exchanger section does not absorb heat and a portion of the refrigerant compressed in the compressor in the internal heat exchanger section releases heat to heat a passenger compartment, and a heat absorption heating operation,in which the refrigerant absorbs heat at the external heat exchanger section, whereby during hot gas heating operation refrigerant is allowed to flow through the external heat exchanger section while heat exchange at the external heat exchanger section is prevented. EFFECTS OF THE INVENTION

[0012] By having these features, the present invention can prevent the accumulation of refrigerant in the external heat exchanger and thus ensure sufficient heating performance in a vehicle air conditioning device having a refrigerant cycle in which switching is carried out between heat absorption heating mode and hot gas heating mode. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic explanatory view of a system configuration example of a vehicle air conditioning apparatus of an embodiment of the present invention. Fig. 2 is an explanatory view of a control device of the vehicle air conditioning device of the embodiment of the present invention. Fig. 3 is an explanatory view of the operation of a refrigerant cycle in the hot gas heating operation of the vehicle air conditioning device of the embodiment of the present invention. Fig. 4 is an explanatory view of the operation of the refrigerant cycle in the heat absorption heating operation of the vehicle air conditioning device of the embodiment of the present invention. Fig. 5 is an explanatory view of the operation of a refrigerant cycle in a refrigerant accumulation prevention operation of the hot gas heating operation. Fig. 6 is a view explaining the basic operation of the vehicle air conditioning device of the embodiment of the present invention. Fig. 7 is an explanatory view of the operation flow of a refrigerant cycle when performing the refrigerant accumulation prevention operation. Fig. 8 is an explanatory view of a configuration example of the control device of an electric vehicle (EV) including the vehicle air conditioning device. DESCRIPTION OF THE EMBODIMENTS

[0013] An embodiment of the present invention is described below with reference to the figures. In the following description, like reference numerals in the different figures refer to parts with the same function, and repeated descriptions of the same for the individual figures are omitted for the sake of simplicity. The bold lines in the refrigerant circuit 10 in the figures indicate the refrigerant flow path along which the refrigerant flows, with the black bold lines indicating the flow of high-pressure refrigerant and the gray bold lines indicating the flow of low-pressure refrigerant. The dashed lines of the refrigerant circuit 10 indicate flow paths in which no refrigerant flows. System configuration

[0014] Fig. 1 schematically shows a configuration example of a vehicle air conditioning device 1 according to an embodiment of the present invention. This configuration example is exemplary and is not limited to a specific configuration.

[0015] The vehicle air conditioning device 1 includes a refrigerant circuit 10 and an air conditioning unit 20. The refrigerant circuit 10 includes a compressor 2, internal heat exchangers 21, 22 provided inside the air conditioning unit 20, and an external heat exchanger 11 provided outside the passenger compartment, which are arranged along a refrigerant flow path. The internal heat exchangers 21, 22 are provided for heat exchange with air flowing inside the air conditioning unit 20, and the external heat exchanger 11 is provided for heat exchange between outside air outside the passenger compartment and the refrigerant.

[0016] The compressor 2 of the refrigerant circuit 10 compresses the refrigerant and circulates it. The refrigerant compressed at the compressor 2 is reduced to the required pressure along a refrigerant flow path selected as needed by passing through a first pressure reduction section V1, a second pressure reduction section V2, a third pressure reduction section V3, and a fourth pressure reduction section V4, which may be, for example, expansion valves. Flow path switching valves 12, 13 are provided on the refrigerant circuit 10 for switching the refrigerant flow path, and check valves 14, 15 are provided as needed to regulate the flow direction of the refrigerant. An accumulator 16 is provided immediately upstream of the compressor 2 in the refrigerant circuit 10, which receives liquid refrigerant and performs gas-liquid separation on the refrigerant.

[0017] As previously mentioned, the air conditioning unit 20 includes internal heat exchangers 21, 22 within it, wherein air introduced by a fan 23 from inside or outside the passenger compartment selectively passes through the internal heat exchangers 21, 22 and is blown into the passenger compartment. A vent 24 is provided on the air conditioning unit 20. When the illustrated vent 24 is fully opened, the air introduced by the fan 23 is blown into the passenger compartment while passing through the two internal heat exchangers 21, 22, and when the vent 24 is fully closed, the air introduced by the fan 23 is blown into the passenger compartment while passing only through the internal heat exchanger 22.Another louver 25 provided on the air conditioning unit 20 serves to switch the air introduced from the fan 23 between air from inside and outside the passenger compartment, and selectively closes an air introduction opening 25A communicating with the passenger compartment exterior and an air introduction opening 25B communicating with the passenger compartment interior.

[0018] The example described shows that a direct heat exchange between the refrigerant and the air takes place at the external heat exchanger 11 and the internal heat exchangers 21, 22. However, the heat exchange between the refrigerant and the air can also take place via a heat transfer medium that exchanges heat with the refrigerant. Thus, a configuration is possible in which the refrigerant absorbs heat from the air via a heat transfer medium, and the heat of the refrigerant is released to the air via a heat transfer medium.

[0019] The vehicle air conditioning device 1 includes, as needed, a heat medium circuit 30. The heat medium circuit 30 circulates a heat medium by means of a circulation pump 31, heats the heat medium by means of an electric coolant heater (ECH) 32, and recovers waste heat from a temperature-regulating object such as a battery or the like by means of a temperature-regulating object heat exchanger 33. A refrigerant-to-heat medium heat exchanger 34 is provided between the refrigerant circuit 10 and the heat medium circuit 30, and performs heat exchange between the refrigerant and the heat medium by means of a refrigerant flow path 34A and a heat medium flow path 34B. Control device

[0020] As in Fig. 2, the vehicle air conditioning device 1 includes a control device 100. The control device 100 controls the refrigerant circuit 10, the air conditioning unit 20, and, if necessary, the heat carrier circuit 30 based on various input signals (air conditioning command signals, charger connection signals, and the like) and detection signals from a sensor unit 40.

[0021] The sensor unit 40, which inputs detection signals to the control device 100, includes, among others, an outside air sensor 41 for detecting the outside air condition, such as outside air temperature, outside air humidity, etc.; a compressor current sensor 42 for detecting the power consumption (energy consumption) of the compressor 2; a refrigerant temperature sensor 43 and a refrigerant pressure sensor 44 for detecting the refrigerant condition; an occupant sensor 45 for detecting whether an occupant is present in the passenger compartment; and a blown air temperature sensor 46 for detecting the blown air temperature of the air conditioning unit 20. These sensors are examples. The sensor unit 40 is equipped with various sensors for detecting the information required for the various controls of the control device 100.

[0022] The control objects of the control device 100 in the refrigerant circuit 10 include, among others, the compressor 2, the first pressure reduction section V1, the second pressure reduction section V2, the third pressure reduction section V3, the fourth pressure reduction section V4, and a closure grille 17; in the air conditioning unit 20, among others, the fan 23 and the ventilation flaps 24, 25; and in the heat transfer medium circuit 30, among others, the circulation pump 31. The control device 100 also controls the vehicle air conditioning device 1 or a communication device 3 of the vehicle (for example, a display device such as a pointer or a monitor, or a voice generation device such as an audio device) based on the processing results of the control device 100. Hot gas heating operation

[0023] In hot gas heating operation, the refrigerant in the external heat exchanger 11 does not absorb heat, and part or all of the refrigerant compressed in the compressor 2 releases heat in the internal heat exchanger 21 to heat a passenger compartment.

[0024] Fig. 3 is an explanatory view of the operation of the refrigerant cycle 10 in the hot gas heating mode (including a preparatory mode). In this mode, a portion of the high-temperature and high-pressure refrigerant discharged from the compressor 2 passes through the internal heat exchanger 21 and the flow path switching valve 12, undergoes pressure reduction at the third pressure-reducing section V3, passes through the refrigerant-heat-transfer medium heat exchanger 34, undergoes gas-liquid separation at the accumulator 16, and returns to the compressor 2. At this time, in the refrigerant cycle 10, since the first pressure-reducing section V1 is completely closed, no refrigerant flows to the external heat exchanger 11. The fourth pressure-reducing section V4 is also completely closed, so no refrigerant flows to the internal heat exchanger 22.

[0025] The refrigerant circuit 10 has a hot gas bypass 10V, which reduces the pressure of at least a portion of the refrigerant compressed in the compressor 2 and returns it to the compressor 2 without passing through the internal heat exchanger 21 and the external heat exchanger 11. At the hot gas bypass 10V, a portion of the high-temperature and high-pressure refrigerant is branched off at a branching point P1 immediately downstream of the compressor 2, undergoes a pressure reduction at the second pressure reduction section V2 (hot gas valve), and combines with low-pressure refrigerant, the pressure of which was reduced at the third pressure reduction section V3, at a merging point P2 immediately upstream of the accumulator 16.

[0026] By providing such a hot gas bypass 10V, the liquid refrigerant condensed by the heat dissipation at the internal heat exchanger 21 is admixed with gaseous refrigerant that has passed through the hot gas bypass 10V, allowing gas-rich refrigerant to be returned to the compressor 2. Furthermore, by increasing the amount of refrigerant flowing through the hot gas bypass 10V, the amount of heat dissipated at the internal heat exchanger 21 can be limited. Therefore, by adjusting the refrigerant flow rate in the hot gas bypass 10V by opening and closing the second pressure reduction section V2 (hot gas valve), the balance between the amount of heat dissipated by the refrigerant circuit 10 and the heat absorption in the compressor 2 can be maintained.

[0027] Since, during hot gas heating operation, the refrigerant flowing through the flow path via the internal heat exchanger 21 is subjected to a pressure reduction at the third pressure reduction section V3, the upstream refrigerant is at high pressure and the downstream refrigerant is at low pressure. To maintain heating performance, it is important that no heat exchange occurs at the refrigerant-to-heat-transfer medium heat exchanger 34 in the low-pressure side flow path. Then, at the air conditioning unit 20, the air introduced by the fan 23 is heated by the heat dissipated at the internal heat exchanger 21 and blown into the passenger compartment. Preparatory operation

[0028] In the preparatory operation performed at the start of the hot gas heating operation, the refrigerant circulates in the refrigerant cycle 10, and heat release in the internal heat exchanger 21 is stopped or restricted until the refrigerant reaches a certain state. As one method, the refrigerant cycle 10 is operated in the above-described hot gas heating operation while the fan 23 of the air conditioning unit 20 is stopped or restricted. As another method, the refrigerant cycle 10 is operated in the above-described hot gas heating operation while the fan 23 of the air conditioning unit 20 is operated, the vent damper 24 is fully closed, and no blown air flows to the internal heat exchanger 21.

[0029] Since the former method stops or restricts the blowing air from the air conditioning unit 20, it is necessary to inform the occupant that the preparatory operation is currently being performed. In contrast, the latter method initially blows air from the air conditioning unit 20 without passing through the internal heat exchanger 21, and the occupant can adjust the blowing air quantity, thus eliminating the occupant's discomfort. Heat absorption heating operation

[0030] Fig. 4 is an explanatory view of the operation of the refrigerant cycle 10 in the heat absorption heating mode. In the heat absorption heating mode, the second pressure reducing section V2, the third pressure reducing section V3, the fourth pressure reducing section V4, and the flow path switching valve 12 in the refrigerant cycle 10 are each fully closed.

[0031] In the heat absorption heating mode, the high-temperature and high-pressure refrigerant discharged from the compressor 2 passes through the internal heat exchanger 21 in the air conditioning unit 20 and undergoes a pressure reduction at the first pressure reducing section V1, after which low-pressure refrigerant passes through the external heat exchanger 11 and is returned to the compressor 2 via the flow path switching valve 13, the check valve 14, and the accumulator 16. At this time, the high-pressure refrigerant discharged from the compressor 2 condenses in the internal heat exchanger 21 and releases heat, and becomes low-pressure refrigerant due to the pressure reduction at the first pressure reducing section V1, absorbs heat at the external heat exchanger 11 and evaporates, and then returns to the compressor 2. Then, at the air conditioning unit 20, the air introduced by the fan 23 is heated by the heat released at the internal heat exchanger 21 and blown into the passenger compartment. Refrigerant accumulation prevention operation

[0032] In Fig. Figure 5 shows the operation of the refrigerant circuit 10 in hot gas heating mode when the accumulation of refrigerant in the external heat exchanger 11 is prevented. During this process, the refrigerant flows in the refrigerant circuit 10 in the Fig. 3, the high-temperature, high-pressure refrigerant that has flowed through the internal heat exchanger 21 is transferred to the external heat exchanger 11 by closing the flow path switching valve 12 and fully opening the first pressure reduction section V1. At this time, the external heat exchanger 11 is in a state where heat dissipation is inhibited. In the example shown, heat dissipation is inhibited by closing a shutter grille 17 installed in front of the external heat exchanger 11, so that the blown air does not pass through the external heat exchanger 11.

[0033] Since the external heat exchanger 11 thus becomes practically a simple refrigerant flow path, hot gas heating operation can be performed in which the heat release point of the refrigerant circuit 10 is limited to the internal heat exchanger 21 and no heat absorption occurs. Since refrigerant flows to the external heat exchanger 11 during this hot gas heating operation, the accumulation of refrigerant in the external heat exchanger 11 can be prevented. This enables a smooth transition when the heat absorption heating operation is subsequently performed in which heat is absorbed from the external heat exchanger 11. Basic operation

[0034] The basic operation of the vehicle air conditioning device 1 by the control device 100 is explained with reference to Fig. 6. When the vehicle air conditioning device 1 starts operating, it enters a signal waiting state in which it waits for an air conditioning command signal (step S01). If a heating command is now input (step S01: YES), it proceeds to the next step S02. If a command other than a heating command (for example, a cooling command) is input (step S01: NO), it proceeds to another air conditioning control according to that command (step S01A).

[0035] In the next step S02, a judgment is made as to whether the hot gas heating operation should be performed. Since the hot gas heating operation is performed in a situation where heat absorption heating is practically impossible, for example, if an extremely low temperature situation is detected by the outside air sensor 41 and therefore it is judged that the hot gas heating operation should be performed (step S02: YES), a transition is made to the next step S03. If it is judged in step S02 that the hot gas heating operation is not performed (step S02: NO), the above-described air intake heating operation is performed (step S11).

[0036] In step S03, it is judged whether condensed refrigerant has accumulated on the external heat exchanger 11 or the refrigerant-heat-transfer medium heat exchanger 34 in the refrigerant cycle 10, for example, based on the state of the refrigerant in the refrigerant cycle 10 or the situation of the heating operation before the start. If it is judged that refrigerant has accumulated and refrigerant recovery is required (step S03: YES), refrigerant recovery processing is performed (step S04). If it is judged in step S03 that refrigerant recovery is not required (step S03: NO), refrigerant recovery processing (step S04) is skipped. If refrigerant recovery processing is performed in steps S09, S10 after the heating end, steps S03, S04 can be omitted here.

[0037] In step S05, the above-described preparatory operation is performed, which is performed when the hot gas heating operation starts. In the preparatory operation, the operation of the refrigerant circuit 10 in the hot gas heating operation is performed in a state where heat release from the refrigerant circuit 10 is either prevented or restricted, so that the circulating refrigerant enters a high-pressure state and energy is stored in the refrigerant. In the preparatory operation (step S05), as already mentioned, the fan 23 of the air conditioning unit 20 is stopped.

[0038] Until it is judged in step S06 that the refrigerant state suitable for performing the hot gas heating operation is reached, the preparatory operation (step S05) is continued (step S06: NO), and meanwhile, processing for informing the occupant is performed so that the occupant of the passenger compartment does not feel worried about equipment malfunction or discomfort because no blown air is blown out from the air conditioning unit 20 (step S06A).

[0039] During the notification to the occupant (occupant notification: step S06A), an output is sent from the control device 100 to the notification device 3, and the occupant is informed that the above-described preparatory operation is currently being performed. As one example, a blinking or monitor display is displayed on a display device of the vehicle, such as a display element or a monitor. As another example, the occupant is informed that the above-described preparatory operation is currently being performed by producing a voice message or a notification tone from a speaker of the vehicle. In this way, it can be conveyed to the occupant that the situation in which blown air is not currently being blown out is not due to a device malfunction, but to the regular preparatory operation of the hot gas heating operation.

[0040] When it is determined that sufficient energy has been stored in the refrigerant during the preparation operation, such as from the detection result of the refrigerant pressure or the detection result of the power consumption of the compressor 2, it is judged that the preparation operation ends (step S06: YES), and the hot gas heating operation in which blown air is blown out is executed (step S07).

[0041] The hot gas heating operation is performed until a heating end command is input (step S08: NO). When the heating end command is input (step S08: YES), the need for refrigerant recovery is judged (step S09) in the same way as in steps S03 and S04. If necessary, refrigerant recovery processing is performed (step S10), after which the air conditioning operation ends. If steps S03 and S04 are executed during the next air conditioning operation, steps S09 and S10 can be omitted.

[0042] If the heat absorption heating operation is performed in step S11, it is continued until a subsequent heating end command is issued (step S12: NO), and when the heating end command is issued (step S12: YES), a judgment of the necessity of refrigerant recovery is performed (step S09), and if necessary, refrigerant recovery processing is performed (step S10), whereupon the air conditioning operation ends. Example of operation when using the refrigerant accumulation prevention mode

[0043] When the refrigerant accumulation prevention operation described above is used, the Fig. 6, the refrigerant recovery processing can be omitted and the Fig. 7 shown operating example. Same steps as in Fig. 6 carry in Fig. 7 identical reference symbols and their repeated description is omitted.

[0044] According to this operation example, during the hot gas heating operation (step S07), the refrigerant accumulation prevention operation is performed in step S07A by closing the flow path switching valve 12 and fully opening the first pressure reducing portion V1, and also closing the shutter grille 17. The hot gas heating operation is performed by using the external heat exchanger 11 as a refrigerant flow path in this refrigerant accumulation prevention operation, through which heat loss is prevented. In this way, since the accumulation of refrigerant in the external heat exchanger 11 is prevented during the hot gas heating operation when the refrigerant flows to the external heat exchanger 11, a smooth transition is enabled when the heat absorption heating operation is subsequently performed in which heat is absorbed from the outside air in the external heat exchanger 11. Configuration of the control device in an electric vehicle (EV)

[0045] As in Fig. As shown in Fig. 8, the control device 100 of the vehicle air conditioning device 1 is configured as an ECU (electronic control unit) connected to various ECUs that control the electric vehicle (EV) via an on-board network L. The control device 100 includes a CPU (central processing unit) 101, ROM (read only memory) 102, RAM (random access memory) 103, an input / output I / F (interface) 104, an internal communication I / F (interface) 105, and the like, with the respective hardware elements being connected to each other via a bus 106.

[0046] The CPU 101 executes the controls of the control device 100 by executing programs stored in the ROM 102. The ROM 102 is a non-volatile memory. For example, the ROM 102 stores programs executed by the CPU 101 and the data required for the CPU 101 to execute the programs. The RAM 103 is a main storage device such as a DRAM (Dynamic Random Access Memory) or an SRAM (Static Random Access Memory). The RAM 103 functions as a work area that the CPU 101 uses when executing programs. The input / output I / F 104 is connected to various sensors and monitors installed in the EV and inputs data to the CPU 101 and outputs data from the calculation processing of the CPU 101. By connecting the internal communication I / F 105 to the on-board network L, the sending and receiving of data with the other ECUs installed in the EV is controlled.

[0047] By inputting environmental information data for the surroundings or data on the operating state of the EV to the control device 100 via the input / output I / F 104 and the internal communication I / F 105, the control of the vehicle air conditioning device 1 is carried out by the programs executed by the CPU 101.

[0048] A battery B is installed in the EV. The battery B is charged by connecting a connector PS of a charger to a battery terminal BP, and the vehicle air conditioning device 1 is supplied with electric power via the battery B. The state of connection of the connector PS to the battery terminal BP is sent to the control device 100 as a charger connection signal via the on-board network L.

[0049] While an embodiment of the present invention has been described in detail above with reference to the figures, the specific embodiments are not limited to this embodiment, and design changes that do not deviate from the spirit of the present invention are also within the scope of the invention. As long as there is no contradiction or problem regarding their purpose, configuration, and the like, the individual techniques of the above embodiment can be transferred and combined with each other. LIST OF REFERENCE SYMBOLS 1 vehicle air conditioning device 2 compressors 3 Notification device (display device) 10 Refrigerant circuit 10V hot gas bypass 11 external heat exchanger 12, 13 Flow path switching valve 14, 15 Check valve 16 accumulator 17 locking grilles 20 air conditioning unit 21, 22 internal heat exchanger 23 fans 30 Heat transfer circuit 31 Circulation pump 32 Heating device 33 temperature control object heat exchangers 34 refrigerant-heat transfer medium heat exchangers 24, 25 Ventilation flap 25A, 25B Air inlet opening 40 Sensor unit 41 Outside air sensor 42 Compressor current sensor 43 Refrigerant temperature sensor 44 Refrigerant pressure sensor 45 Occupant sensor 46 Blown air temperature sensor 100 control device V1 first pressure reduction section V2 second pressure reduction section V3 fourth pressure reduction section V3 fourth pressure reduction section

Claims

[1] Vehicle air conditioning device comprising a refrigerant circuit with a compressor, an internal heat exchanger section and an external heat exchanger section, an air conditioning unit in which the internal heat exchanger section is arranged, and a control device that controls the refrigerant circuit and the air conditioning unit, wherein the refrigerant circuit has a hot gas bypass which reduces the pressure of at least part of the refrigerant compressed in the compressor and returns it to the compressor without passing through the internal heat exchanger section and the external heat exchanger section, wherein the control device can perform a hot gas heating operation in which the refrigerant in the external heat exchanger section does not absorb heat and a part of the refrigerant compressed in the compressor releases heat in the internal heat exchanger section to heat a passenger compartment, and a heat absorption heating operation in which the refrigerant at the external heat exchanger section absorbs heat, wherein during hot gas heating operation, refrigerant is allowed to flow through the external heat exchanger section while heat exchange at the external heat exchanger section is prevented. [2] The vehicle air conditioning device according to claim 1, wherein the refrigerant circuit includes a bypass flow path through which the refrigerant flowed out from the internal heat exchanger portion bypasses the external heat exchanger portion, and flow path switching means that switches between the bypass flow path and a refrigerant flow path through which refrigerant flows to the external heat exchanger, wherein during the hot gas heating operation, the bypass flow path is closed by the flow path switching means and refrigerant flows to the external heat exchanger portion. [3] The vehicle air conditioning device according to claim 1 or 2, wherein the control device inhibits heat dissipation at the external heat exchanger portion by closing a shutter provided at the external heat exchanger portion.

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