Vehicle air conditioning system

Abstract

Vehicle air conditioning device (1) comprising a refrigerant circuit (R) comprising a compressor (2) for compressing a refrigerant, a radiator (4) for allowing the refrigerant to radiate heat, a pressure reducing unit (6, 8), and a heat absorber (9) for allowing the refrigerant to absorb heat, wherein the air of a vehicle interior is air-conditioned, wherein the vehicle air conditioning device (1) comprises a control device (32) for controlling the compressor (2), wherein a standard time is defined during which the refrigerant circuit (R) is filled with a sufficient quantity of refrigerant, wherein the control device (32) has standard time data specifying a ratio between a refrigerant intake temperature Ts and a refrigerant discharge temperature Td of the compressor (2) to the standard time, and the control device (32) is configured to derive from the standard time data, based on the current refrigerant intake temperature Ts,to calculate an estimated refrigerant discharge temperature value Tdst, which is an estimated value of the refrigerant discharge temperature Td at normal time, and to compare the estimated refrigerant discharge temperature value Tdst and the current refrigerant discharge temperature Td, thereby assessing a refrigerant shortage in the refrigerant circuit (R).

Description

Technical FieldThe present invention relates to an air conditioning device of a heat pump system that air-condition air of a vehicle interior, and more particularly, to an air conditioning device applicable to a hybrid car and an electric vehicle.Prior ArtIn order to cope with an increase in environmental problems in recent years, hybrid cars and electric vehicles have been spread. Moreover, as an air conditioning device applicable to such a vehicle, a device including a compressor for compressing and discharging a refrigerant, a radiator disposed on a vehicle interior side for radiating the refrigerant heat, a heat absorber disposed on the vehicle interior side for allowing the refrigerant to absorb heat, an outdoor heat exchanger disposed outside the vehicle interior for allowing the refrigerant to radiate heat or absorb heat, and first and second expansion valves has been developed, and a heating operation is performed of allowing the refrigerant discharged from the compressor to radiate heat in the radiator, decompressing the refrigerant from which the heat has been radiated in this radiator by the first expansion valve, and then allowing the refrigerant to absorb heat in the outdoor heat exchanger, a dehumidifying and heating operation or a dehumidifying and cooling operation of heat radiating the refrigerant discharged from the compressor in the radiator and heat absorbing the refrigerant from which the heat has been radiated in the radiator in the heat absorber, and a cooling operation of heat radiating the refrigerant discharged from the compressor in the outdoor heat exchanger, decompressing the refrigerant by the second expansion valve, and then heat absorbing the refrigerant in the heat absorber are changed and executed.Moreover, an accumulator is disposed on a refrigerant suction side of the compressor, and the refrigerant is once accumulated in this accumulator to perform gas-liquid separation, and the refrigerant gas is sucked into the compressor, preventing or inhibiting liquid from returning to the compressor (see, e.g., Patent Document 1)In Patent Document 2, an air conditioning apparatus is disclosed that includes a refrigerant circuit including a compressor, a radiator, a pressure reducing unit, and a heat absorber. Based on a plurality of parameters, in particular during a heating operation with different configurations of the air conditioning device, a refrigerant filling state is evaluated and optionally automatically filled.In Patent Document 3, refrigeration circuits including the components as mentioned in Patent Document 2 are disclosed. A lack of refrigerant or a refrigerant overfill is determined by means of detection of subcooling downstream of a radiator, and an opening degree of the pressure reducing unit for achieving a predetermined overheat stomab of a heat absorber is adjusted and compared with a target opening degree.List of referencesPatent DocumentsPatent Document 1: Japanese Patent Application Publication JP 2012-228 945 APatent Document 2: US 2009 / 0126375 A1Patent Document 3: EP 2 902 728 A1SUMMARY OF THE INVENTIONProblems to be Solved by the InventionHere, as time passes, a refrigerant gradually leaks from a refrigerant circuit of a vehicle air conditioner, but heretofore, there has been no choice except to protect and stop the compressor after almost all the refrigerant leaks from the refrigerant circuit. This also applies to a case where an amount of the refrigerant to be included in the circuit during operation or the like is small.The present invention has been developed to solve such conventional technical problems, and an object thereof is to provide a vehicle air conditioning apparatus capable of judging refrigerant shortage due to, for example, leakage of the refrigerant with elapse of time as early as possible and protecting a compressor.Means for Solving the ProblemsA vehicle air conditioning apparatus of the invention of claim 1 includes a refrigerant circuit having a compressor for compressing a refrigerant, a radiator for radiating the refrigerant, a pressure reducing unit, and a heat absorber for allowing the refrigerant to absorb heat, thereby air-conditioning air of a vehicle compartment, and the vehicle air conditioning apparatus includes a controller for controlling the compressor, and is characterized in that this controller has normal time data indicating a relationship between a refrigerant suction temperature Ts and a refrigerant discharge temperature Td of the compressor to a normal time when the refrigerant circuit is filled with a sufficient amount of the refrigerant, and the controller has an estimated refrigerant discharge temperature value Tdst from these normal time data, the estimated value of the refrigerant discharge temperature Td is at the normal time, based on the current refrigerant suction temperature Ts, calculated, and compares this estimated refrigerant discharge temperature value Tdst and the current refrigerant discharge temperature Td, thereby judging refrigerant shortage of the refrigerant circuit.The vehicle air conditioning device of the invention of claim 2 is characterized in that, in the above invention, the normal time data is data indicating a ratio of the refrigerant suction temperature Ts and a refrigerant discharge pressure Pd of the compressor to the refrigerant discharge temperature Td at the normal time when the refrigerant circuit is filled with the sufficient amount of the refrigerant.The vehicle air conditioning device of the invention of claim 3 is characterized in that in the above respective inventions, the normal time data is a multiple regression equation in which the refrigerant discharge temperature estimated value Tdst is regarded as an auxiliary controlled variable and the refrigerant suction temperature Ts and the refrigerant discharge pressure Pd of the compressor are regarded as explanatory variables.A vehicle air conditioning apparatus of the invention of claim 4 includes a refrigerant circuit having a compressor for compressing a refrigerant, a radiator for radiating the refrigerant, a pressure reducing unit, and a heat absorber for allowing the refrigerant to absorb heat, thereby air-conditioning air of a vehicle compartment, and the vehicle air conditioning apparatus includes a controller for controlling the compressor, and is characterized in that this controller has normal time data indicating a relationship between a refrigerant suction temperature Ts and a refrigerant discharge pressure Pd of the compressor at a normal time when the refrigerant circuit is filled with a sufficient amount of the refrigerant, and the controller calculates an estimated refrigerant discharge pressure value Pdst from these normal time data, the estimated value of the refrigerant discharge pressure Pd is at the normal time based on the current refrigerant suction temperature Ts, and compares this estimated refrigerant discharge pressure value Pdst and the current refrigerant discharge pressure Pd, thereby judging refrigerant shortage of the refrigerant circuit.The vehicle air conditioning device of the invention of claim 5 is characterized in that in the above invention, the normal time data is data indicating a ratio of the refrigerant suction temperature Ts and a refrigerant discharge temperature Td of the compressor to the refrigerant discharge pressure Pd at the normal time when the refrigerant circuit is filled with the sufficient amount of the refrigerant.The vehicle air conditioning device of the invention of claim 6 is characterized in that in the above invention, the normal time data is a multiple regression equation in which the refrigerant discharge pressure estimated value Pdst is regarded as an auxiliary controlled variable and the refrigerant suction temperature Ts and the refrigerant discharge temperature Td of the compressor are regarded as explanatory variables.The vehicle air conditioning device of the invention of claim 7 is characterized in that in the above respective inventions, when it is judged that there is a suspected refrigerant shortage of the refrigerant circuit, the control device decreases a capacity of the compressor.The vehicle air conditioning device of the invention of claim 8 is characterized in that the control device in the above invention decreases the capacity of the compressor and then determines occurrence of refrigerant shortage of the refrigerant circuit via conditions that a difference between the estimated refrigerant discharge temperature value Tdst and the current refrigerant discharge temperature Td or a difference between the estimated refrigerant discharge pressure value Pdst and the current refrigerant discharge pressure Pd increases.The vehicle air conditioning device of the invention of claim 9 is characterized in that in the invention of claim 1 to claim 6, when it is judged that there is a suspected refrigerant shortage of the refrigerant circuit, the control device restricts a used bandwidth of a rotational speed NC of the compressor, compares again the estimated refrigerant discharge temperature value Tdst and the current refrigerant discharge temperature Td in this state, or compares the estimated refrigerant discharge pressure value Pdst and the current refrigerant discharge pressure Pd, and determines the occurrence of the refrigerant shortage of the refrigerant circuit.The vehicle air conditioning device of the invention of claim 10 is characterized in that, in the above invention, in a state where the used bandwidth of the rotational speed NC of the compressor is limited, the control device determines the occurrence of the refrigerant shortage of the refrigerant circuit while a difference between the refrigerant discharge estimated temperature value Tdst and the current refrigerant discharge temperature Td or a difference between the refrigerant discharge estimated pressure value Pdst and the current refrigerant discharge pressure Pd is smaller.The vehicle air conditioning device of the invention of claim 11 is characterized in that in the invention of claim 8 to claim 10, when the occurrence of the refrigerant shortage of the refrigerant circuit is determined, the control device performs a predetermined notification operation.The vehicle air conditioning device of the invention of claim 12 is characterized in that in the invention of claim 8 to claim 11, when the occurrence of the refrigerant shortage of the refrigerant circuit is determined, the control device decreases the rotational speed NC of the compressor or stops the compressor.Advantageous Effect of the InventionIn a vehicle air conditioning apparatus including a refrigerant circuit having a compressor for compressing a refrigerant, a radiator for radiating the refrigerant, a pressure reducing unit, and a heat absorber for allowing the refrigerant to absorb heat, thereby air-conditioning air of a vehicle compartment, for example, when the refrigerant gradually leaks from the refrigerant circuit and an amount of the refrigerant in the refrigerant circuit finally decreases, a refrigerant suction pressure Ps of the compressor decreases. When the refrigerant suction pressure Ps of the compressor decreases, the refrigerant to be sucked into the compressor becomes an over-heat degree SH.When the refrigerant to be sucked into the compressor reaches the superheat degree SH, a refrigerant discharge temperature Td of the compressor changes to increase even at the same refrigerant suction temperature Ts and the same refrigerant discharge pressure Pd of the compressor, and the refrigerant discharge pressure Pd changes to decrease even at the same refrigerant suction temperature Ts and the same refrigerant discharge temperature Td.In order to solve this problem, in the invention of claim 1, the controller has normal time data indicating a relationship between the refrigerant suction temperature Ts and a refrigerant discharge temperature Td of the compressor at a normal time when the refrigerant circuit is filled with a sufficient amount of the refrigerant, and the controller calculates, from this normal time data, on the basis of the current refrigerant suction temperature Ts, an estimated refrigerant discharge temperature value Tdst that is the estimated value of the refrigerant discharge temperature Td to the normal time, and compares this estimated refrigerant discharge temperature value Tdst and the current refrigerant discharge temperature Td, thereby judging a refrigerant shortage of the refrigerant circuit. Consequently, when the refrigerant gradually leaks from the refrigerant circuit or when the amount of the refrigerant trapped in the refrigerant circuit during operation or the like is small, it is possible to detect occurrence of the refrigerant shortage early.In this case, as in the invention of claim 2, the normal time data is regarded as data indicating a ratio of the refrigerant suction temperature Ts and the refrigerant discharge pressure Pd of the compressor to the refrigerant discharge temperature Td to the normal time when the refrigerant circuit is filled with the sufficient amount of the refrigerant. Consequently, it is possible to accurately calculate the refrigerant discharge temperature estimated value Tdst.Specifically, as in the invention of claim 3, the normal time data is regarded as a multiple regression equation in which the refrigerant discharge temperature estimated value Tdst is regarded as an auxiliary controlled variable and the refrigerant suction temperature Ts and the refrigerant discharge pressure Pd of the compressor are regarded as explanatory variables. When the refrigerant discharge temperature estimated value Tdst is obtained from the current refrigerant suction temperature Ts and the refrigerant discharge pressure Pd in the multiple regression equation, it is possible to accurately calculate the refrigerant discharge temperature estimated value Tdst.Moreover, in the invention of claim 4, the control means has normal time data indicating a relationship between a refrigerant suction temperature Ts and a refrigerant discharge pressure Pd of the compressor at a normal time when the refrigerant circuit is filled with a sufficient amount of the refrigerant, and the control means calculates from this normal time data an estimated refrigerant discharge pressure value Pdst, which is the estimated value of the refrigerant discharge pressure Pd at the normal time, based on the present refrigerant suction temperature Ts, and compares this estimated refrigerant discharge pressure value Pdst and the present refrigerant discharge pressure Pd, thereby judging the refrigerant shortage of the refrigerant circuit. Consequently, when the refrigerant gradually leaks from the refrigerant circuit or when the amount of the refrigerant trapped in the refrigerant circuit during operation or the like is small, it is possible to detect the occurrence of the refrigerant shortage early as well.Also in this case, as in the invention of claim 5, the normal time data is regarded as data indicating a ratio of the refrigerant suction temperature Ts and a refrigerant discharge temperature Td of the compressor to the refrigerant discharge pressure Pd at the normal time when the refrigerant circuit is filled with the sufficient amount of the refrigerant. Consequently, it is possible to accurately calculate the refrigerant discharge pressure estimated value Pdst.Moreover, as in the invention of claim 6, the normal time data is regarded as a multiple regression equation in which the refrigerant discharge pressure estimated value Pdst is regarded as an auxiliary controlled variable, and the refrigerant suction temperature Ts and the refrigerant discharge temperature Td of the compressor are regarded as explanatory variables. Similarly, when the refrigerant discharge pressure estimated value Pdst is obtained from the refrigerant suction temperature Ts and the refrigerant discharge temperature Td in the multiple regression equation, it is possible to further accurately calculate the refrigerant discharge pressure estimated value Pdst.Then, as in the invention of claim 7, when it is judged that there is a suspected refrigerant shortage of the refrigerant circuit, the control means decreases a capacity of the compressor. Consequently, it is possible to perform protection before the compressor noises to a range where there is a possibility of its failure, and it is also possible to notify a user of the suspected refrigerant shortage while avoiding the disadvantage that the compressor is seriously damaged in advance.In this case, as in the invention of claim 8, the control means decreases the capacity of the compressor and then determines an occurrence of the refrigerant shortage of the refrigerant circuit via conditions that a difference between the refrigerant discharge estimated temperature value Tdst and the current refrigerant discharge temperature Td or a difference between the refrigerant discharge estimated pressure value Pdst and the current refrigerant discharge pressure Pd increases. Consequently, it is possible to highly accurately grasp the occurrence of refrigerant shortage of the refrigerant circuit by two stages of judgments.Moreover, as in the invention of claim 9, when it is judged that there is a suspected refrigerant shortage of the refrigerant circuit, the controller restricts a used bandwidth of a rotational speed NC of the compressor. Also in this case, it is possible to perform protection before the compressor noises into the range where there is a possibility of its failure, and it is also possible to notify a user of the suspected refrigerant shortage while avoiding the disadvantage that the compressor is seriously damaged in advance.Specifically, in a state where the used bandwidth of the rotational speed NC of the compressor is restricted, the controller again compares the refrigerant discharge estimated temperature value Tdst and the current refrigerant discharge temperature Td, or compares the refrigerant discharge estimated pressure value Pdst and the current refrigerant discharge pressure Pd, and determines the occurrence of refrigerant shortage of the refrigerant circuit. Moreover, as in the invention of claim 10, the control means determines the occurrence of the refrigerant shortage of the refrigerant circuit while a difference between the refrigerant discharge estimated temperature value Tdst and the current refrigerant discharge temperature Td or a difference between the refrigerant discharge estimated pressure value Pdst and the current refrigerant discharge pressure Pd is smaller. Consequently, it is possible to accurately and quickly detect the occurrence of refrigerant shortage of the refrigerant circuit by two stages of judgments.Then, as in the invention of claim 11, when the occurrence of the refrigerant shortage of the refrigerant circuit is determined, the control means performs a predetermined notification operation. Consequently, it is possible to warn the user of the refrigerant shortage occurring, thereby assisting a quick reaction.Moreover, as in the invention of claim 12, when the occurrence of the refrigerant shortage of the refrigerant circuit is determined, the controller decreases the rotational speed NC of the compressor or stops the compressor. Consequently, it is possible to previously avoid the disadvantage that the compressor is damaged according to the occurrence of the refrigerant shortage of the refrigerant circuit, thereby protecting the compressor.Brief Description of the DrawingsFIG. 1 is a constitutional view of a vehicle air conditioning device of an embodiment to which the present invention is applied (a heating mode, a dehumidifying and heating mode, a dehumidifying and cooling mode, and a cooling mode in Embodiment 1); FIG. 2 is a block diagram of an electric circuit of a controller of the air conditioner of FIG. 1 ; FIG. 3 is a constitutional view when the air conditioner of FIG. 1 is in a MAX cooling mode (the maximum cooling mode); FIG. 4 is a schematic cross-sectional view of an accumulator of the vehicle air conditioning apparatus of FIG. 1 ; FIG. 5 is a P-h diagram in the heating mode of the vehicle air conditioning apparatus of FIG. 1 ; FIG. 6 is a diagram showing an estimated multiple regression estimation value and a multiple regression error in the heating mode; FIG. 7 is a diagram showing an estimated multiple regression estimation value and a multiple regression error in a mode other than the heating mode; and FIG. 8 is a constitutional view of a vehicle air-conditioning device of another embodiment of the present invention (Embodiment 2).Mode for Carrying Out the InventionHereinafter, a description will be made of embodiments of the present invention in detail with reference to the drawings.Embodiment 1FIG. 1 is a constitutional view of a vehicle air conditioning device 1 of an embodiment of the present invention. A vehicle of the embodiment to which the present invention is applied is an electric vehicle (EV) in which an engine (an internal combustion engine) is not mounted and which travels with an electric motor for traveling driven by energy stored in a battery (not shown in the drawings), and the vehicle air conditioning apparatus 1 of the present invention is also driven by the energy of the battery. Specifically, in the electric vehicle that is unable to perform heating by engine waste heat, the vehicle air conditioning device 1 of the embodiment performs a heating mode by a heat pump operation in which a refrigerant circuit is used, and moreover, the air conditioning device selectively performs respective modes of a dehumidifying and heating mode, a dehumidifying and cooling mode, a cooling mode, and a MAX cooling mode (the maximum cooling mode).Note that the vehicle is not limited to the electric vehicle, and the present invention is also effective for a so-called hybrid car in which the engine is used together with the electric motor for traveling. Moreover, it is needless to say that the present invention is also applicable to a normal car running with the internal combustion engine.The vehicle air conditioning device 1 of the embodiments performs air conditioning (heating, cooling, dehumidifying, and ventilating) of a vehicle interior of the electric vehicle, and there are sequentially provided, through a refrigerant pipe 13, an electric type of a compressor 2 for compressing a refrigerant, a radiator 4 disposed in an air flow passage 3 of an HVAC unit 10 in which vehicle interior air passes and circulates, for sending the high-temperature high-pressure refrigerant discharged from the compressor 2 via a refrigerant pipe 13G and letting this refrigerant radiate heat into the vehicle interior, an outdoor expansion valve 6 as a pressure reducing unit formed of an electric valve that decompresses and expands the refrigerant during heating, an outdoor heat exchanger 7, A refrigerant circuit R is formed by a refrigerant circuit R that is disposed outside the vehicle compartment and performs heat exchange between the refrigerant and outside air to function as the radiator during cooling and function as an evaporator (a heat absorber) during heating, an interior expansion valve 8 as a pressure reducing unit formed of an electric valve to decompress and expand the refrigerant, a heat absorber 9 disposed in the air flow passage 3 to let the refrigerant absorb heat from the interior and the exterior of the vehicle during cooling and during dehumidifying, an accumulator 12, and others.Moreover, this refrigerant circuit R is filled with a predetermined amount of refrigerant and a predetermined amount of lubricating oil. Note that an outdoor blower 15 is provided in the outdoor heat exchanger 7. The outdoor blower 15 forcibly sends the outside air through the outdoor heat exchanger 7 to perform the heat exchange between the outside air and the refrigerant, and the outside air passes through the outdoor heat exchanger 7 even during a stop of the vehicle (i.e., a speed is 0 km / h).In addition, the outdoor heat exchanger 7 has a dryer-fitted liquid tank portion 14 and a supercooling portion 16 in sequence on a refrigerant downstream side, and a refrigerant pipe 13A extending from the outdoor heat exchanger 7 is connected to the dryer-fitted liquid tank portion 14 via a solenoid valve 17 for cooling to be opened in the dehumidifying and heating mode, the dehumidifying and cooling mode, the cooling mode and the MAX cooling mode. A refrigerant pipe 13B on an outlet side of the supercooling portion 16 is connected to an inlet side of the heat absorber 9 via the indoor expansion valve 8. Note that the dryer-core liquid tank portion 14 and the supercooling portion 16 structurally form a part of the outdoor heat exchanger 7.Moreover, the refrigerant pipe 13B is disposed between the supercooling portion 16 and the indoor expansion valve 8 in a heat exchanging relationship with a refrigerant pipe 13C on an outlet side of the heat absorber 9, and both of the pipes constitute an indoor heat exchanger 19.Moreover, the refrigerant pipe 13A extending from the outdoor heat exchanger 7 branches to a refrigerant pipe 13D, and this branched refrigerant pipe 13D communicates and connects to the refrigerant pipe 13C on a downstream side of the indoor heat exchanger 19 via a solenoid valve 21 for heating to be opened in the heating mode. The refrigerant pipe 13C is connected to the accumulator 12, and the accumulator 12 is connected to a refrigerant suction side of the compressor 2. In addition, a refrigerant pipe 13E on an outlet side of the radiator 4 is connected to an inlet side of the outdoor heat exchanger 7 via the outdoor expansion valve 6.Moreover, a solenoid valve 30 for warming-up, which is to be opened in the heating mode, the dehumidifying and cooling mode, and the cooling mode and is to be closed in the dehumidifying and heating mode and the MAX cooling mode, is disposed between an discharge side of the compressor 2 and an inlet side of the radiator 4 in the refrigerant pipe 13G. In this case, the refrigerant pipe 13G on an upstream side of the solenoid valve 30 branches to a bypass pipe 35, and this bypass pipe 35 communicates and connects to the refrigerant pipe 13E on a downstream side of the outdoor expansion valve 6 via a solenoid valve 40 for bypassing which is to be opened in the dehumidifying and heating mode and the MAX cooling mode and is to be closed in the heating mode, the dehumidifying and cooling mode and the cooling mode. The bypass pipe 35, the solenoid valve 30, and the solenoid valve 40 constitute a bypass device 45.Thus, the bypass pipe 35, the solenoid valve 30, and the solenoid valve 40 constitute the bypass device 45, so that it is possible to smoothly switch from the dehumidifying and heating mode or the MAX cooling mode to directly send the refrigerant discharged from the compressor 2 into the outdoor heat exchanger 7 as described later to the heating mode, the dehumidifying and cooling mode, or the cooling mode to send the refrigerant discharged from the compressor 2 into the radiator 4.Moreover, on an air flow upstream side of the heat absorber 9, in the air flow passage 3, respective suction ports such as an outside air suction port and an inside air suction port are formed (illustrated by a suction port 25 in FIG. 1 ), and in the suction port 25, a suction switching damper 26 is disposed to switch the air to be introduced into the air flow passage 3 to the inside air that is air of the vehicle interior (an inside air circulation mode) and outside air that is air outside the vehicle interior (an outside air introduction mode). Moreover, on an air flow downstream side of the suction switching damper 26, an indoor blower (blower fan) 27 is disposed to supply the introduced indoor or outdoor air to the air flow passage 3.In addition, in FIG. 1, reference numeral 23 denotes an auxiliary heater as an auxiliary heater disposed in the vehicle air-conditioning device 1 of the embodiment. The auxiliary heater 23 of the embodiment is formed of a PTC heater which is an electric heater and is disposed in the air flow passage 3 to the flow of the air in the air flow passage 3 on an air flow upward side of the radiator 4. Then, when the auxiliary heater 23 is energized to generate heat, the air in the air flow passage 3 flowing into the radiator 4 through the heat absorber 9 is heated. That is, the auxiliary heater 23 becomes a so-called heater core to perform or supplement heating of the vehicle interior.Moreover, in the air flow passage 3 on an air flow upstream side of the auxiliary heater 23, an air mix damper 28 is disposed to adjust an amount in which the air (the indoor or outdoor air) in the air flow passage 3, which flows into the air flow passage 3 and is guided by the heat absorber 9, passes through the auxiliary heater 23 and the radiator 4. Further, in the air flow passage 3 on an air downstream side of the radiator 4, each of a foot, ventilation, or defroster outlet (represented by an outlet 29 in FIG. 1 ) is formed, and in the outlet 29, an outlet switching damper 31 is disposed to execute a change control of blowing the air from each outlet mentioned above.Next, in FIG. 2, reference numeral 32 denotes a controller (ECU) as a controller formed of a microcomputer, which is an example of a computer including a processor, and an input of the controller 32 is provided with respective outputs of an outside air temperature sensor 33 that detects an outside air temperature (Tam) of the vehicle, an outside air humidity sensor 34 that detects an outside air humidity, an HVAC suction temperature sensor 36 that detects a temperature of the air to be sucked from the suction port 25 to the air flow passage 3, an inside air temperature sensor 37 that detects a temperature of the air of the vehicle interior (the inside air), an inside air humidity sensor 38 that detects a humidity of the air of the vehicle interior, an inside air CO 2- concentration sensor 39, which detects a carbon dioxide concentration of the vehicle interior, an outlet temperature sensor 41 which detects a temperature of the air to be blown out from the outlet 29 to the vehicle interior, an ejection pressure sensor 42 which detects a pressure Pd of the refrigerant ejected from the compressor 2, an ejection temperature sensor 43 which detects a temperature Td of the refrigerant ejected from the compressor 2, a suction pressure sensor 44 which detects a pressure Ps of the refrigerant to be sucked into the compressor 2, a suction temperature sensor 55 which detects a refrigerant suction temperature Ts which is a temperature of the refrigerant ejected from the accumulator 12 to be sucked into the compressor 2, a radiator temperature sensor 46, A temperature of the radiator 4 (the temperature of the air passed through the radiator 4 or the temperature of the radiator 4 itself: a radiator temperature TH), a radiator pressure sensor 47 that detects a refrigerant pressure of the radiator 4 (the pressure of the refrigerant in the radiator 4 or immediately after the refrigerant flows out from the radiator 4: a radiator pressure PCI), a heat absorber temperature sensor 48 that detects a temperature of the heat absorber (the temperature of the air passed through the heat absorber 9 or the temperature of the heat absorber 9 itself: a heat absorber temperature Te), a heat absorber pressure sensor 49 that detects a refrigerant pressure of the heat absorber 9 (the pressure of the refrigerant in the heat absorber 9 or immediately after the refrigerant flows out from the heat absorber 9), a solar irradiation sensor 51 of, for example, a photosensor system for detecting a solar irradiation amount into the vehicle, a speed sensor 52 for detecting a moving speed (speed) of the vehicle, an air conditioner operation portion 53 for adjusting changing a predetermined temperature or switching between operation modes, an outdoor heat exchanger temperature sensor 54 that detects a temperature of the outdoor heat exchanger 7 (the temperature immediately after the refrigerant flows out from the outdoor heat exchanger 7 or the temperature of the refrigerant flowing into the accumulator 12 in the heating mode mentioned below: an outdoor heat exchanger temperature TXO), and an outdoor heat exchanger pressure sensor 56, detecting a refrigerant pressure of the outdoor heat exchanger 7 (the pressure of the refrigerant in the outdoor heat exchanger 7 or immediately after the refrigerant flows out from the outdoor heat exchanger 7: an outdoor heat exchanger pressure PXO). Moreover, the input of the controller 32 is further connected to an output of an auxiliary heater temperature sensor 50 that detects a temperature of the auxiliary heater 23 (the temperature immediately after the air is heated by the auxiliary heater 23, or the temperature of the auxiliary heater 23 itself: an auxiliary heater temperature Tptc).On the other hand, an output of the controller 32 is connected to the compressor 2, the outdoor blower 15, the indoor blower (blower fan) 27, the suction switching damper 26, the air mixing damper 28, the discharge switching damper 31, the outdoor expansion valve 6, the indoor expansion valve 8, the auxiliary heater 23, and the respective solenoid valves, i.e., the solenoid valve 30 (for warming up), the solenoid valve 17 (for cooling), the solenoid valve 21 (for heating), and the solenoid valve 40 (for bypassing). Then, the controller 32 controls these components on the basis of the outputs of the respective sensors and the setting input by the air conditioner operation portion 53.Next, a description will be made of an operation of the vehicle air-conditioning device 1 of the embodiment having the above composition. In the embodiment, the controller 32 switches and executes the respective operation modes of the heating mode, the dehumidifying and heating mode, the dehumidifying and cooling mode, the cooling mode, and the MAX cooling mode. A description will be made first of all about a flow of the refrigerant and an overview of control in each mode.(1) Heating modeWhen the heating mode is selected by the controller 32 (an automatic mode) or a manual operation on the air conditioner operation portion (a manual mode), the controller 32 opens the solenoid valve 21 (for heating) and closes the solenoid valve 17 (for cooling). In addition, the control device opens the solenoid valve 30 (for warming-up) and closes the solenoid valve 40 (for bypassing).Then, the controller operates the compressor 2 and the respective blowers 15 and 27, and the air mix damper 28 has, as shown by a broken line in FIG. 1, a state of sending all the air in the air flow passage 3 blown out from the indoor blower 27 and passed through the heat absorber 9 to the auxiliary heater 23 and the radiator 4. consequently, a high-temperature high-pressure refrigerant gas discharged from the compressor 2 flows into the radiator 4 through the solenoid valve 30 and the refrigerant pipe 13G. The air in the air flow passage 3 passes through the radiator 4, and thus the air in the air flow passage 3 is heated by the high-temperature refrigerant in the radiator 4 (in the auxiliary heater 23 and the radiator 4 when the auxiliary heater 23 operates), whereas the refrigerant in the radiator 4 is taken out of heat by the air and cooled to condense and liquify.The refrigerant liquefied in the radiator 4 flows out from the radiator 4 and then flows through the refrigerant pipe 13E to reach the outdoor expansion valve 6. The refrigerant flowing into the outdoor expansion valve 6 is decompressed therein, and then flows into the outdoor heat exchanger 7, The refrigerant flowing into the outdoor heat exchanger 7 evaporates, and the heat is conveyed in from the outside air passed through by traveling or the outdoor blower 15. In other words, the refrigerant circuit R functions as a heat pump. Then, the low-temperature refrigerant flowing out from the outdoor heat exchanger 7 flows through the refrigerant pipe 13A, the solenoid valve 21, and the refrigerant pipe 13D, and flows from the refrigerant pipe 13C into the accumulator 12 to perform gas-liquid separation therein, and then the refrigerant gas is sucked into the compressor 2, and this circulation is repeated.Here, FIG. 4 shows a cross-sectional view of this accumulator 12, the accumulator 12 is a so-called gas-liquid separator for separating a liquid refrigerant and a refrigerant gas flowing in through the refrigerant pipe 13C, and the accumulator is formed of a tank 57 having a predetermined vertical dimension and having a predetermined volume therein, a baffle 58 disposed in an upper portion of this tank 57 and disposed away from side walls and an upper wall of the tank 57, and an outlet pipe 61 entering an interior of the tank 57 from the upper wall thereof, extends through the baffle 58, goes down once to a lower portion of the tank 57, and then rises so that its raised distal end opens with a clearance below the baffle 58.The lowermost portion of the outlet pipe 61 is located with a slight clearance above the bottom wall of the container 57, and an oil return hole 62 of a small hole is formed in this lowermost portion. Moreover, an upper end of the discharge pipe 61 extends from the upper wall of the container 57 and is connected to the suction side of the compressor 2. Then, the refrigerant pipe 13C enters the inside of the tank 57 from the upper wall thereof and is open above the baffle 58.As described above, the refrigerant gas evaporated in the outdoor heat exchanger 7 and the non-evaporated liquid refrigerant flow through the refrigerant pipe 13A, the solenoid valve 21, and the refrigerant pipe 13D, and as shown by an arrow in FIG. 4, flows from the refrigerant pipe 13C in the tank 57 of the accumulator 12, The refrigerant that has flowed into the tank 57 in a mixed gas-and-liquid state first collides with the baffle 58 to expand outward, and passes through a clearance between an outer edge of the baffle 58 and the tank 57 to flow downward, as shown by arrows, to a lower portion of the tank 57.The liquid refrigerant is accumulated in the lower portion of the container 57, and the refrigerant gas and the refrigerant gas resulting from the liquid refrigerant evaporated in the accumulator 12 flow, as shown by an arrow, through a clearance between the distal end of the outlet pipe 61 and the baffle 58, flows from an opening at the distal end of the outlet pipe 61 to an inside of the outlet pipe 61, flows downward, rises again, and flows out from the accumulator 12. Further, oil (for lubricating the compressor 2) circulating together with the refrigerant in the refrigerant circuit R is also accumulated in the reservoir 57. This oil and a part of the liquid refrigerant enter the inside of the outlet pipe 61 from the oil return hole 62 formed in the lowermost portion of the outlet pipe 61 and flow out of the accumulator 12.The liquid refrigerant in the refrigerant and oil flowing out from the accumulator 12 as described above absorbs heat from the outside to evaporate in a process of reaching the compressor 2, and thus only the refrigerant gas and oil are sucked into the compressor 2. The suction temperature sensor 55 detects the temperature of this refrigerant (the refrigerant suction temperature Ts).The air heated in the radiator 4 (in the auxiliary heater 23 and the radiator 4 when the auxiliary heater 23 operates) is blown out from the outlet 29, thereby performing the heating of the vehicle interior. In this case, the controller 32 calculates a target radiator pressure PCO (a target radiator pressure PCI) from a target radiator temperature TCO (a target radiator temperature TH) calculated from a target outlet temperature TAO mentioned below, and controls a rotational speed of the compressor 2 on the basis of the target radiator pressure PCO and the refrigerant pressure of the radiator 4 detected by the radiator pressure sensor 47 (the radiator pressure PCl which is a high pressure of the refrigerant circuit R). Moreover, the controller 32 controls a valve position of the outdoor expansion valve 6 on the basis of the temperature (the radiator temperature TH) of the radiator 4 detected by the radiator temperature sensor 46 and the radiator pressure PCI detected by the radiator pressure sensor 47, and controls a supercooling degree SC of the refrigerant in an outlet of the radiator 4 (calculated from the radiator temperature TH and the radiator pressure PCI) to a predetermined target supercooling degree TGSC which is a target value of the supercooling degree. The target radiator temperature TCO is basically regarded as TCO=TAO, but a predetermined control limit is provided.Moreover, in this heating mode, when a heating capability by the radiator 4 becomes a heating capability required for vehicle interior air conditioning, the controller 32 controls the power supply to the auxiliary heater 23 to supplement the shortage by the heat generation of the auxiliary heater 23. Consequently, comfortable vehicle interior heating is achieved and frost formation on the exterior heat exchanger 7 is prevented. At this time, the auxiliary heater 23 is disposed on the air flow upstream side of the radiator 4, and thus the air flowing through the air flow passage 3 is passed through the auxiliary heater 23 in front of the radiator 4.Here, when the auxiliary heater 23 is disposed on the air flow downstream side of the radiator 4, and when the auxiliary heater 23 is formed of the PTC heater as in the embodiment, the temperature of the air flowing into the auxiliary heater 23 rises due to the radiator 4. Therefore, a resistance value of the PTC heater increases and a current value decreases to also decrease a heat amount to be generated, but the auxiliary heater 23 is disposed on the air flow upstream side of the radiator 4, so that it is possible to sufficiently exert a performance of the auxiliary heater 23 formed of the PTC heater as in the embodiment.(2) Dehumidifying and Heating ModeNext, in the dehumidifying and heating mode, the controller 32 opens the solenoid valve 17 and closes the solenoid valve 21, and further, the controller closes the solenoid valve 30, opens the solenoid valve 40, and sets the valve position of the outdoor expansion valve 6 to a shut-off position. Then, the controller operates the compressor 2 and the respective blowers 15 and 27. as shown by the broken line in FIG. 1, the air mix damper 28 reaches a state of sending all the air in the air flow passage 3 blown out from the indoor blower 27 and passed through the heat absorber 9 to the auxiliary heater 23 and the radiator 4.Consequently, the high-temperature high-pressure refrigerant gas discharged from the compressor 2 to the refrigerant pipe 13G flows into the bypass pipe 35 without flowing toward the radiator 4, and flows through the solenoid valve 40 to reach the refrigerant pipe 13G on the downstream side of the outdoor expansion valve 6. At this time, the outdoor expansion valve 6 is shut off, and thus the refrigerant flows into the outdoor heat exchanger 7, The refrigerant flowing into the outdoor heat exchanger 7 is cooled therein by traveling or the outside air passed through the outdoor blower 15 to condense. The refrigerant flowing out from the outdoor heat exchanger 7 flows from the refrigerant pipe 13A subsequently through the solenoid valve 17 into the dryer-fitted liquid tank portion 14 and the supercooling portion 16.The refrigerant flowing out from the supercooling portion 16 of the outdoor heat exchanger 7 enters the refrigerant pipe 13B and flows through the indoor heat exchanger 19 to reach the indoor expansion valve 8. In the indoor expansion valve 8, the refrigerant is decompressed and then flows into the heat absorber 9 to evaporate. By a heat absorbing operation at this time, the air blown out from the indoor blower 27 is cooled and water in the air is coagulated to adhere to the heat absorber 9. Therefore, the air in the air flow passage 3 is cooled and dehumidified. The refrigerant evaporated in the heat absorber 9 flows through the indoor heat exchanger 19 and the refrigerant pipe 13C to reach the accumulator 12 to perform the gas-liquid separation therein as described above, and then the refrigerant is sucked into the compressor 2, and this circulation is repeated.At this time, the valve position of the outdoor expansion valve 6 is set to the shutoff position, so that it is possible to suppress or prevent the disadvantage that the refrigerant discharged from the compressor 2 flows back into the radiator 4 from the outdoor expansion valve 6. Consequently, it is possible to suppress or eliminate a decrease in an amount of the refrigerant to be circulated, thereby achieving air-conditioning capability. Moreover, in this dehumidifying and heating mode, the controller 32 supplies power to the auxiliary heater 23 to generate heat. Consequently, the air cooled and dehumidified in the heat absorber 9 is further heated in a process of passing through the auxiliary heater 23, and thus a temperature rises, thereby performing dehumidifying and heating of the vehicle interior.The controller 32 controls the rotational speed of the compressor 2 on the basis of the temperature of the heat absorber 9 (the heat absorber temperature Te) detected by the heat absorber temperature sensor 48 and a target heat absorber temperature TEO which is a target value of the heat absorber temperature, and the controller controls the power supply (heat generation) of the auxiliary heater 23 on the basis of the auxiliary heater temperature Tptc detected by the auxiliary heater temperature sensor 50 and the above-mentioned target radiator temperature TCO. Consequently, the drop in temperature of the air blown out from the outlet 29 to the vehicle interior is reliably prevented by the heating of the auxiliary heater 23, while the cooling and dehumidifying of the air in the heat absorber 9 is suitably performed.Consequently, the temperature of the air blown out to the vehicle interior can be controlled at an appropriate heating temperature while dehumidifying the air, and it is possible to achieve comfortable and efficient dehumidifying and heating of the vehicle interior. Moreover, as described above, in the dehumidifying and heating mode, the air mixing damper 28 has a state of sending all the air in the air flow passage 3 through the auxiliary heater 23 and the radiator 4.Note that the auxiliary heater 23 is disposed on the air flow upstream side of the radiator 4, and thus the air heated by the auxiliary heater 23 passes through the radiator 4. However, in this dehumidifying and heating mode, the refrigerant does not flow through the radiator 4, and thus it is possible to eliminate the disadvantage that the heat from the air heated by the auxiliary heater 23 is absorbed by the radiator 4. Specifically, it is possible to prevent the temperature drop of the air blown out to the vehicle interior through the radiator 4, and efficiency (COP) improves.(3) Dehumidifying and Cooling ModeNext, in the dehumidifying and cooling mode, the controller 32 opens the solenoid valve 17 closes the solenoid valve 21, the controller also opens the solenoid valve 30 and closes the solenoid valve 40, then the controller operates the compressor 2 and the respective blowers 15 and 27, and the air mix damper 28 has, as shown by the broken line in FIG. 1, the state of sending all the air in the air flow passage 3 that is blown out from the indoor blower 27 and passed through the heat absorber 9, Thus, the high-temperature high-pressure refrigerant gas discharged from the compressor 2 flows through the solenoid valve 30 and flows from the refrigerant pipe 13G into the radiator 4. the air in the air flow passage 3 passes through the radiator 4, and thus the air in the air flow passage 3 is heated by the high-temperature refrigerant in the radiator 4, whereas the heat is taken from the refrigerant in the radiator 4 by the air and cooled to condense and liquify.The refrigerant flowing out from the radiator 4 flows through the refrigerant pipe 13E to reach the outdoor expansion valve 6, and flows through the outdoor expansion valve 6 controlled to slightly open to flow into the outdoor heat exchanger 7. The refrigerant flowing into the outdoor heat exchanger 7 is cooled therein by the traveling or the outside air passed through the outdoor blower 15 to condense. The refrigerant flowing out from the outdoor heat exchanger 7 flows from the refrigerant pipe 13A through the solenoid valve 17 to subsequently flow into the dryer-core liquid tank portion 14 and the supercooling portion 16. In this case, the refrigerant is subcooled.The refrigerant flowing out from the supercooling portion 16 of the outdoor heat exchanger 7 enters the refrigerant pipe 13B and flows through the indoor heat exchanger 19 to reach the indoor expansion valve 8. The refrigerant is decompressed in the indoor expansion valve 8, and then flows into the heat absorber 9 to evaporate. The water in the air blown out from the indoor blower 27 coagulates to adhere to the heat absorber 9 by the heat absorbing operations at this time, and thus the air is cooled and dehumidified.The refrigerant evaporated in the heat absorber 9 flows through the indoor heat exchanger 19 and the refrigerant pipe 13C and reaches the accumulator 12 to perform the gas-liquid separation therein as described above, and the refrigerant is sucked into the compressor 2, this circulation being repeated. In this dehumidifying and cooling mode, the controller 32 does not supply power to the auxiliary heater 23, and thus the air cooled and dehumidified in the heat absorber 9 is reheated in the process of passing through the radiator 4 (radiation performance during warming is lower than that during heating). Consequently, dehumidifying and cooling of the vehicle interior is performed.The controller 32 controls the rotational speed of the compressor 2 based on the temperature of the heat absorber 9 (the heat absorber temperature Te) detected by the heat absorber temperature sensor 48, also controls the valve position of the outdoor expansion valve 6 based on the above-mentioned high pressure of the refrigerant circuit R, and controls the refrigerant pressure of the radiator 4 (the radiator pressure PCI).(4) Cooling ModeNext, in the cooling mode, the controller 32 sets the valve position of the outdoor expansion valve 6 to a fully opened position in the above state of the dehumidifying and cooling mode. Note that the controller 32 controls the air mix damper 28 to set a ratio at which the air in the air flow passage 3 blown out from the indoor blower 27 and passed through the heat absorber 9 passes through the auxiliary heater 23 and the radiator 4, as shown by a solid line FIG. 1. Moreover, the controller 32 does not supply power to the auxiliary heater 23.Consequently, the high-temperature high-pressure refrigerant gas discharged from the compressor 2 flows through the solenoid valve 30 and flows from the refrigerant pipe 13G into the radiator 4, and the refrigerant flowing out from the radiator 4 flows through the refrigerant pipe 13E to reach the outdoor expansion valve 6. At this time, the outdoor expansion valve 6 is fully opened, and thus the refrigerant passes through the outdoor expansion valve to flow as it is into the outdoor heat exchanger 7, in which the refrigerant therein is cooled by the traveling or the outside air passed through the outdoor blower 15 to condense and liquify. The refrigerant flowing out from the outdoor heat exchanger 7 flows from the refrigerant pipe 13A through the solenoid valve 17 to subsequently flow into the dryer-core liquid tank portion 14 and the supercooling portion 16. In this case, the refrigerant is subcooled.The refrigerant flowing out from the supercooling portion 16 of the outdoor heat exchanger 7 enters the refrigerant pipe 13B and flows through the indoor heat exchanger 19 to reach the indoor expansion valve 8. The refrigerant is decompressed in the indoor expansion valve 8, and then flows into the heat absorber 9 to evaporate. By the heat absorbing operations at this time, the air blown out from the indoor blower 27 is cooled. Moreover, the water coagulates in the air to adhere to the heat absorber 9.The refrigerant evaporated in the heat absorber 9 flows through the indoor heat exchanger 19 and the refrigerant pipe 13C and reaches the accumulator 12 to perform the gas-liquid separation therein as described above, and then the refrigerant is sucked into the compressor 2, this circulation being repeated. The air cooled and dehumidified in the heat absorber 9 is blown out from the outlet 29 to the vehicle interior (a part of the air passes through the radiator 4 to perform heat exchange), wherein the cooling of the vehicle interior is performed. In this cooling mode, the controller 32 controls the rotational speed of the compressor 2 also on the basis of the temperature of the heat absorber 9 (the heat absorber temperature Te) detected by the heat absorber temperature sensor 48 and the target heat absorber temperature TEO which is the target value of the heat absorber temperature.(5) MAX Cooling Mode (Maximum Cooling Mode)Next, in the MAX cooling mode, which is the maximum cooling mode, the controller 32 opens the solenoid valve 17 and closes the solenoid valve 21, The controller also closes the solenoid valve 30, opens the solenoid valve 40, and sets the valve position of the outdoor expansion valve 6 to the shutoff position. Then, as shown in FIG. 3, the controller operates the compressor 2 and the respective blowers 15 and 27, and the air mix damper 28 has a state in which the air in the air flow passage 3 does not pass through the auxiliary heater 23 and the radiator 4. However, there are no problems even if the air passes slightly. Moreover, the controller 32 does not supply power to the auxiliary heater 23.Consequently, the high-temperature high-pressure refrigerant gas discharged from the compressor 2 to the refrigerant pipe 13G flows into the bypass pipe 35 without flowing toward the radiator 4, and flows through the solenoid valve 40 to reach the refrigerant pipe 13E on the downstream side of the outdoor expansion valve 6. At this time, the outdoor expansion valve 6 is shut off, and thus the refrigerant flows into the outdoor heat exchanger 7, The refrigerant flowing into the outdoor heat exchanger 7 is cooled therein by traveling or the outside air passed through the outdoor blower 15 to condense. The refrigerant flowing out from the outdoor heat exchanger 7 flows from the refrigerant pipe 13A through the solenoid valve 17 subsequently into the dryer-fitted liquid tank portion 14 and the supercooling portion 16.The refrigerant flowing out from the supercooling portion 16 of the outdoor heat exchanger 7 enters the refrigerant pipe 13B and flows through the indoor heat exchanger 19 to reach the indoor expansion valve 8. In the indoor expansion valve 8, the refrigerant is decompressed and then flows into the heat absorber 9 to evaporate. By the heat absorbing operation at this time, the air blown out from the indoor blower 27 is cooled. Moreover, the water coagulates in the air to adhere to the heat absorber 9, and thus the air in the air flow passage 3 is dehumidified. The refrigerant evaporated in the heat absorber 9 flows through the indoor heat exchanger 19 and the refrigerant pipe 13C to reach the accumulator 12 and flows therethrough to be sucked into the compressor 2, and this circulation repeats. At this time, the outdoor expansion valve 6 is shut off, so that it is also possible to suppress or prevent the disadvantage that the refrigerant discharged from the compressor 2 flows back from the outdoor expansion valve 6 into the radiator 4. Consequently, it is possible to suppress or eliminate the decrease in the amount of the refrigerant to be circulated, and it is possible to acquire the air-conditioning capability.Here, in the above-mentioned cooling mode, the high temperature refrigerant flows through the radiator 4, and thus direct heat conduction from the radiator 4 to the HVAC unit 10 occurs remarkably, but the refrigerant does not flow through the radiator 4 in this MAX cooling mode. Consequently, forcibly cooling the vehicle interior is performed, and, especially in an environment in which the outside air temperature Tam is high, the vehicle interior can be quickly cooled to achieve the comfortable air conditioning of the vehicle interior. Also in this MAX cooling mode, the controller 32 controls the rotational speed of the compressor 2 on the basis of the temperature of the heat absorber 9 (the heat absorber temperature Te) detected by the heat absorber temperature sensor 48 and the target heat absorber temperature TEO which is the target value of the heat absorber temperature.(6) Switching between respective modesThe air circulated in the air flow passage 3 is subjected to cooling from the heat absorber 9 and a heating operation from the radiator 4 (and the auxiliary heater 23) (adjusted by the air mix damper 28) in the above respective operation modes, and the air is blown out from the outlet 29 into the vehicle interior. The controller 32 calculates the target outlet temperature TAO on the basis of the outside air temperature Tam detected by the outside air temperature sensor 33, the temperature of the vehicle interior detected by the interior air temperature sensor 37, the blower voltage, the solar radiation amount detected by the solar radiation sensor 51, and others, and the target vehicle interior temperature (the predetermined temperature) set at the air conditioner operation portion 53. The controller switches between the respective modes and controls the temperature of the air blown out from the outlet 29 at this target outlet temperature TAO.In this case, the controller 32 switches the respective operation modes on the basis of parameters such as the outside air temperature Tam, the humidity of the vehicle interior, the target outlet temperature TAO, the radiator temperature TH, the target radiator temperature TCO, the heat absorber temperature Te, the target heat absorber temperature TEO, and a presence / absence of a requirement for dehumidifying the vehicle interior. Consequently, according to environmental conditions or a need for dehumidifying, the controller switches among the heating mode, the dehumidifying and heating mode, the dehumidifying and cooling mode, the cooling mode and the MAX cooling mode with accuracy, thereby achieving comfortable and efficient air conditioning of the vehicle interior.(7) Judgment of Refrigerant Shortage by Controller 32 (No. 1)Next, a description will be made for a control of a refrigerant shortage judgment of the refrigerant circuit R by the controller 32 with reference to FIGS. 5 to 7. In particular, in the vehicle air conditioning device 1 for use in an environment in which there is more vibration than in an environment of a conventional vehicle air conditioning device, there is a problem that the refrigerant gradually leaks from the refrigerant circuit R during use with a lapse of time. Moreover, there is also a case where the amount of refrigerant enclosed in the refrigerant circuit R is insufficient during operation. When the amount of refrigerant in the refrigerant circuit R decreases and becomes insufficient, the compressor 2 is seriously damaged. Therefore, in protecting equipment, it is extremely important to judge occurrence of refrigerant shortage early.Here, the refrigerant to be sucked into the compressor 2 is accumulated in the accumulator 12. However, for example, when the refrigerant gradually leaks from the refrigerant circuit R and the amount of the refrigerant in the refrigerant circuit finally decreases, or when the amount of the refrigerant or the like trapped during operation is small and thus the refrigerant in the refrigerant circuit R becomes short, the refrigerant suction pressure Ps of the compressor 2 decreases and the amount of the refrigerant accumulated in the accumulator 12 also decreases. When the refrigerant suction pressure Ps of the compressor 2 decreases and the amount of the refrigerant in the accumulator 12 also decreases, the refrigerant to be sucked into the compressor 2 becomes the superheat degree SH. When the refrigerant to be sucked into the compressor 2 becomes the superheat degree SH, the refrigerant discharge temperature Td changes to increase even at the same refrigerant suction temperature Ts and the same refrigerant discharge pressure Pd, and the refrigerant discharge pressure Pd changes to decrease even at the same refrigerant suction temperature Ts and the same refrigerant discharge temperature Td.Next, this behavior will be described with reference to FIG. 5. FIG. 5 is a P-h diagram of the refrigerant circuit R in, for example, the above-mentioned heating mode. Moreover, in this drawing, a line indicated by L 1 indicates a case where a sufficient amount of the refrigerant is enclosed in the refrigerant circuit R, and a line indicated by L 2 indicates a case where the amount of the refrigerant is insufficient. In addition, L3indicates a line of saturated vapor.As is also apparent from this drawing, the temperature of the refrigerant in the accumulator 12 is the outdoor heat exchanger temperature TXO (at -5° C. in this example), and the amount of the refrigerant is sufficient. In this case, in a process, when the refrigerant flows out from the accumulator 12 (shown with TXO in FIG. 5 ) until the refrigerant is sucked into the compressor 2 (shown with Ts in FIG. 5 ), the temperature substantially decreases along the saturated vapor L 3 line, and the refrigerant suction temperature Ts is at -10° C. (TS of the line L 1 in FIG. 5 ) in this case. Then, the refrigerant discharge temperature Td of the refrigerant compressed in the compressor 2 is about + 90° C. (shown with Tdst in FIG. 5 ).On the other hand, for example, when the refrigerant gradually leaks from the refrigerant circuit R and the amount of the refrigerant becomes insufficient, the amount of the liquid refrigerant accumulated in the accumulator 12 also decreases. Consequently, the liquid refrigerant flowing out from the accumulator 12 decreases or the liquid refrigerant hardly flows out. Therefore, the refrigerant to be sucked into the compressor 2 becomes the superheat degree SH due to an influence of ambient heat, and the refrigerant discharge temperature Td increases to about +105° C. (shown with Td in FIG. 5 ) even at the same refrigerant suction temperature Ts (Ts=-10° C. of the line L 2 in FIG. 5 ).Thus, in this example, the controller 32 has normal time data indicating a relationship between the refrigerant suction temperature Ts and the refrigerant discharge temperature Td of the compressor 2 at a normal time when the refrigerant circuit R is filled with the sufficient amount of the refrigerant, and the controller calculates from this normal time data an estimated refrigerant discharge temperature value Tdst (Tdst is shown in FIG. 5 ) which is the estimated value of the refrigerant discharge temperature Td to the normal time based on the current refrigerant suction temperature Ts, and the controller 32 compares this estimated refrigerant discharge temperature value Tdst and the current refrigerant discharge temperature Td (Td is shown in FIG. 5 ), thereby judging the refrigerant shortage of the refrigerant circuit R.(7-1) Normal Time DataIn this embodiment, these normal time data are a multiple regression equation in which the above refrigerant discharge estimated temperature value Tdst is regarded as an auxiliary controlled variable, and the refrigerant suction temperature Ts and the refrigerant discharge pressure Pd are regarded as explanatory variables. This multiple regression equation of the embodiment is given by equation (I) as follows. wherein A and B are coefficients of partial regression and C is a constant. The controller 32 sets the current refrigerant suction temperature Ts and the current refrigerant discharge pressure Pd in Equation (I), and calculates the refrigerant discharge temperature estimated value Tdst, which is the estimated value of the refrigerant discharge temperature Td at the normal time.FIG. 6 is a diagram in which an ordinate represents the refrigerant discharge temperature estimated value Tdst (a multiple regression estimated value) calculated as described above and an abscissa represents the current refrigerant discharge temperature Td (an actual refrigerant discharge temperature value), and shows a refrigerant discharge temperature estimation error (a multiple regression error) that is an error between both of the values. In this drawing, when the estimated multiple regression estimation value is on an inclined straight line, the error is zero. In this case, the calculated estimated multiple regression estimation value slightly deviates from this inclined straight line, but the error between both of the values (the multiple regression error) is within a predetermined tolerance. It can be judged that the data is sufficiently usable. Moreover, FIG. 7 shows cooling system conditions other than the above heating conditions (a mode other than the heating mode). Also in this case, a multiple regression error is within the predetermined tolerance, and it is understood that the data can be sufficiently used.(7-2) Judgment of Suspected of Refrigerant ShortageThe controller 32 compares the estimated refrigerant discharge temperature value Tdst calculated as described above and the current refrigerant discharge temperature Td. For example, when the current refrigerant discharge temperature Td is higher than the refrigerant discharge temperature estimated value Tdst+α (for example, 10 K or the like), that is, when (Tdst+α)<Td, it is judged that there is a suspected refrigerant shortage of the refrigerant circuit R (a Kältemittelverknappungsverdachtsmerker is set).(7-3) Determination of Occurrence of Refrigerant Shortage (No. 1)As described above, when it is judged that there is the suspected refrigerant shortage of the refrigerant circuit R, the controller 32 in the embodiment decreases an upper limit of the rotational speed NC of the compressor 2 (decreases from, for example, 8000 min -1 to 3000 min -1 or the like as usual) to decrease a capacity of the compressor 2. In this state, the controller calculates the refrigerant discharge temperature estimated value Tdst again, and again judges whether or not the current refrigerant discharge temperature Td is higher than the refrigerant discharge temperature estimated value Tdst+β (for example, 15 K or the like), which is much larger than the above difference (α<β).Then, when (Tdst+β)<Td, the controller 32 determines the occurrence of refrigerant shortage of the refrigerant circuit R. When the occurrence of refrigerant shortage is determined, the controller 32 decreases the rotational speed NC of the compressor 2 down to, for example, a minimum control rotational speed or stops the compressor, and also displays the occurrence of refrigerant shortage in the air conditioner operation portion 53 to notify a user (a notification operation). Consequently, while protecting the compressor 2, the controller alerts the user of the occurrence of the refrigerant shortage, thus enabling a quick response. Note that, for example, when (Tdst+β)<Td does not set within a predetermined time after the capacity of the compressor 2 is lowered, the controller 32 cancels the suspected refrigerant shortage (resets the Kältemittelverknappungsverdachtsmerker).In this way, the controller 32 has the normal time data indicating the relationship between the refrigerant suction temperature Ts and the refrigerant discharge temperature Td of the compressor 2 in the normal time when the refrigerant circuit R is filled with the sufficient amount of the refrigerant, and the controller 32 calculates, from these normal time data, the refrigerant discharge temperature estimated value Tdst, which is the estimated value of the refrigerant discharge temperature Td to the normal time, based on the current refrigerant suction temperature Ts, and compares this refrigerant discharge temperature estimated value Tdst and the current refrigerant discharge temperature Td, thereby judging the refrigerant shortage of the refrigerant circuit R. Consequently, when the refrigerant gradually leaks from the refrigerant circuit R or when the amount of the refrigerant enclosed in the refrigerant circuit R is small during operation or the like, it is possible to detect the occurrence of the refrigerant shortage early.In this case, the normal time data is regarded as the multiple regression equation in which the refrigerant discharge temperature estimated value Tdst is regarded as an auxiliary controlled variable and the refrigerant suction temperature Ts and the refrigerant discharge pressure Pd are regarded as explanatory variables, and the refrigerant discharge temperature estimated value Tdst is obtained from the current refrigerant suction temperature Ts and the refrigerant discharge pressure Pd in the multiple regression equation. Consequently, it is possible to accurately calculate the refrigerant discharge temperature estimated value Tdst.Moreover, when it is judged that there is the suspected refrigerant shortage of the refrigerant circuit R, the controller 32 decreases the upper limit of the rotational speed NC of the compressor 2 to reduce the performance of the compressor 2. Consequently, it is possible to perform protection before the compressor 2 noises into a range where there is a possibility of its failure, and it is also possible to notify the user of the suspected refrigerant shortage while avoiding the disadvantage that the compressor 2 is seriously damaged in advance.Then, the controller 32 decreases the capacity of the compressor 2, and then determines the occurrence of refrigerant shortage of the refrigerant circuit R under conditions that a difference between the refrigerant discharge temperature estimated value Tdst and the current refrigerant discharge temperature Td increases (the difference α is increased to the difference β). Consequently, it is possible to highly accurately grasp the occurrence of the refrigerant shortage of the refrigerant circuit R by two stages of judgments.(7-4) Determination of Occurrence of Refrigerant Shortage (No. 2)Here, a description will be made of another example of a determination operation of the occurrence of the refrigerant shortage of the refrigerant circuit R by the controller 32. In this example, when it is judged that there is the suspected refrigerant shortage of the refrigerant circuit R, the controller 32 limits a used bandwidth of the rotational speed NC of the compressor 2. For example, the controller sets the rotational speed NC of the compressor 2 to a constant low value (3000 min -1 or the like). Consequently, it is possible to perform the protection before the compressor 2 noises into the area where there is the possibility of its failure, and it is also possible to notify the user of the suspected refrigerant shortage while avoiding the disadvantage that the compressor 2 is seriously damaged in advance.Next, in a state where the used bandwidth of the rotational speed NC of the compressor 2 is limited (the rotational speed is constant in this embodiment), the controller compares the refrigerant discharge estimated temperature value Tdst and the current refrigerant discharge temperature Td again, and determines the occurrence of the refrigerant shortage of the refrigerant circuit R. In this case, the controller 32 determines the occurrence of the refrigerant shortage of the refrigerant circuit R while the difference between the refrigerant discharge estimated temperature value Tdst and the current refrigerant discharge temperature Td is smaller (the difference is 5 K, or the like, for example, and γ: (Tdst+γ)<Td) (γ<α). That is, in this case as well, the controller performs two stages of judgments, limits the used bandwidth of the rotational speed NC of the compressor 2, and decreases the difference (γ). Consequently, it is possible to highly accurately and quickly detect the occurrence of the refrigerant shortage of the refrigerant circuit R with high sensitivity. Moreover, the controller likewise reduces the rotational speed NC of the compressor 2 down to, for example, the minimum control rotational speed or stops the compressor, and displays the occurrence of the refrigerant shortage to the air conditioner operation portion 53 to notify the user (the notification operation).(8) Judgment of Refrigerant Shortage by Controller 32 (No. 2)In the refrigerant shortage judgment (No. 1) from the above (7), the controller compares the refrigerant discharge temperature Td of the compressor 2 and the refrigerant discharge temperature estimated value Tdst, which is the estimated value of the refrigerant discharge temperature Td at the normal time, thereby judging the refrigerant shortage of the refrigerant circuit R, but the present invention is not limited thereto. As shown by a broken line in FIG. 5, the refrigerant discharge pressure Pd decreases at the same refrigerant discharge temperature Td. Therefore, the controller can compare the refrigerant discharge pressure Pd of the compressor 2 and the refrigerant discharge pressure estimated value Pdst at the normal time to perform the judgment. That is, when the refrigerant shortage occurs at the same refrigerant suction temperature Ts and the same refrigerant discharge temperature Td, the refrigerant discharge pressure Pd changes to decrease.Thus, in this example, the controller 32 has normal time data indicating a relationship between the refrigerant suction temperature Ts and the refrigerant discharge pressure Pd of the compressor 2 at the normal time when the refrigerant circuit R is filled with the sufficient amount of the refrigerant, and the controller calculates from this normal time data an estimated refrigerant discharge pressure value Pdst (Pdst is shown in FIG. 5 ) which is the estimated value of the refrigerant discharge pressure Pd at the normal time, based on the current refrigerant suction temperature Ts, and the controller 32 compares this estimated refrigerant discharge pressure value Pdst and the current refrigerant discharge pressure Pd (Pd is shown in FIG. 5 ), thereby judging the refrigerant shortage of the refrigerant circuit R.(8-1) Normal Time DataThe normal time data is also a multiple regression equation in this case, in which in the embodiment, the above refrigerant discharge pressure estimated value Pdst is regarded as an auxiliary controlled variable, and the refrigerant suction temperature Ts and the refrigerant discharge temperature Td are regarded as explanatory variables. This multiple regression equation of this embodiment is given by equation (II) as follows. wherein D and E are coefficients of partial regression and F is a constant. The controller 32 sets the current refrigerant suction temperature Ts and the current refrigerant discharge temperature Td in Equation (II), and calculates the refrigerant discharge pressure estimated value Pdst, which is the estimated value of the refrigerant discharge pressure Pd at the normal time.(8-2) Judgment of Suspected of Refrigerant ShortageThe controller 32 compares the estimated refrigerant discharge pressure value Pdst calculated as described above and the current refrigerant discharge pressure Pd. For example, when the current refrigerant discharge pressure Pd is lower than the refrigerant discharge pressure estimated value Pdst-α, i.e., when (Pdst-α)>Pd, it is judged that there is a suspected refrigerant shortage of the refrigerant circuit R (a Kältemittelverknappungsverdachtsmerker is set).(8-3) Determination of Occurrence of Refrigerant Shortage (No. 1)As described above, when it is judged that there is the suspected refrigerant shortage of the refrigerant circuit R, for example, the controller 32 decreases the upper limit of the rotational speed NC of the compressor 2 (e.g., decreases from usually 8000 min -1 down to 3000 min -1 or the like) to decrease the performance of the compressor 2. In this state, the controller calculates the refrigerant discharge pressure estimated value Pdst again and again judges whether the current refrigerant discharge pressure Pd is lower than the refrigerant discharge pressure estimated value Pdst - β which is much larger than the above difference (α < β). Then, when (Pdst- β)>Pd, the controller 32 determines the occurrence of the refrigerant shortage of the refrigerant circuit R. When the occurrence of the refrigerant shortage is determined, the controller 32 reduces the rotational speed NC of the compressor to, for example, the minimum control rotational speed or stops the compressor, and also displays the occurrence of the refrigerant shortage to the air conditioner operation portion 53 to notify the user (the notification operation). Consequently, while protecting the compressor 2, the controller alerts the user of the occurrence of the refrigerant shortage, thereby promoting the quick response. Note that, for example, when (Pdst- β)>Pd does not set within a predetermined time after the capacity of the compressor 2 is lowered, the controller 32 cancels the suspected refrigerant shortage (resets the Kältemittelverknappungsverdachtsmerker).In this way, the controller 32 has the normal time data indicating the relationship between the refrigerant suction temperature Ts and the refrigerant discharge pressure Pd of the compressor 2 at the normal time when the refrigerant circuit R is filled with the sufficient amount of the refrigerant, and the controller 32 calculates from this normal time data the refrigerant discharge pressure estimated value Pdst, which is the estimated value of the refrigerant discharge pressure Pd at the normal time, based on the current refrigerant suction temperature Ts, and compares this refrigerant discharge pressure estimated value Pdst and the current refrigerant discharge pressure Pd, thereby judging the refrigerant shortage of the refrigerant circuit R. Likewise, when the refrigerant gradually leaks from the refrigerant circuit R or when the amount of the refrigerant trapped in the refrigerant circuit R during operation or the like is small, it is possible to detect the occurrence of the refrigerant shortage early.In this case, the normal time data is regarded as the multiple regression equation in which the refrigerant discharge pressure estimated value Pdst is regarded as an auxiliary controlled variable and the refrigerant suction temperature Ts and the refrigerant discharge temperature Td are regarded as explanatory variables, and the refrigerant discharge pressure estimated value Pdst is obtained from the current refrigerant suction temperature Ts and the refrigerant discharge temperature Td in the multiple regression equation. Consequently, it is possible to accurately calculate the refrigerant discharge pressure estimated value Pdst.Moreover, when it is judged that there is the suspected refrigerant shortage of the refrigerant circuit R, the controller 32 decreases the upper limit of the rotational speed NC of the compressor 2 to reduce the performance of the compressor 2. Consequently, it is possible to perform the protection before the compressor 2 noises into the area where there is the possibility of its failure, and it is also possible to notify the user of the suspected refrigerant shortage while avoiding the disadvantage that the compressor 2 is seriously damaged in advance.Then, the controller 32 decreases the capacity of the compressor 2, and then determines the occurrence of refrigerant shortage of the refrigerant circuit R under conditions that a difference between the refrigerant discharge pressure estimated value Pdst and the current refrigerant pressure Pd increases (the difference α is increased to the difference β). Consequently, it is also possible to highly accurately grasp the occurrence of the refrigerant shortage of the refrigerant circuit R by two stages of judgments.(8-4) Determination of Occurrence of Refrigerant Shortage (No. 2)In this case as well, when it is similarly judged that there is the suspected refrigerant shortage of the refrigerant circuit R, the controller 32 may restrict the used bandwidth of the rotational speed NC of the compressor 2. Moreover, in a state where the used bandwidth of the rotational speed NC of the compressor 2 is limited (the rotational speed is constant in the embodiment), the controller may compare the refrigerant discharge pressure estimated value Pdst and the current refrigerant discharge pressure Pd again and determine the occurrence of the refrigerant shortage of the refrigerant circuit R. In this case as well, the controller 32 determines the occurrence of the refrigerant shortage of the refrigerant circuit R while a difference between the refrigerant discharge pressure estimated value Pdst and the current refrigerant discharge pressure Pd is smaller (the difference γ: (Pdst-γ)>Pd) (γ<α). Specifically, in this case as well, the controller performs the judgment of two stages, limits the used range of the rotational speed NC of the compressor 2, and reduces the difference, so that it is possible to highly accurately and quickly detect the occurrence of the refrigerant shortage of the refrigerant circuit R with high sensitivity. Moreover, similarly, the controller reduces the rotational speed NC of the compressor 2 to the minimum control rotational speed or stops the compressor and displays the occurrence of the refrigerant shortage to the air conditioner operation portion 53, thereby notifying the user (the notification operation).Embodiment 2Next, FIG. 8 is a constitutional view of a vehicle air conditioning device 1 of another embodiment to which the present invention is applied. Note that in this drawing, components denoted by the same reference numerals as in FIG. 1 or 3 exhibit the same or similar functions. In this embodiment, an outlet of a supercooling portion 16 is connected to a check valve 82, and an outlet of the check valve 82 is connected to a refrigerant pipe 13B. Note that a refrigerant pipe 13B (an indoor expansion valve 8) side of the check valve 82 is regarded as a forward direction.Moreover, a refrigerant pipe 13E on an outlet side of a radiator 4 branches before an outdoor expansion valve 6, and this branched refrigerant pipe (hereinafter referred to as a second bypass pipe) 83 communicates and connects to the refrigerant pipe 13B via the solenoid valve 80 (for dehumidifying) and the check valve 81 on a downstream side of the check valve 82. Note that a side of a refrigerant pipe 13B of the check valve 82 is regarded as a forward direction. Then, the solenoid valve 80 is also connected to an output of a control unit 32. The other components are the same as those of the above-mentioned embodiment of FIG. 1 or FIG. 3, and a description thereof is omitted.A description will be made for an operation of the vehicle air-conditioning device 1 of this embodiment having the above constitution. Also in this embodiment, the controller 32 switched and executes respective operation modes of a heating mode, a dehumidifying and heating mode, a dehumidifying and cooling mode, a cooling mode, and a MAX cooling mode (a maximum cooling mode). Note that when the heating mode, the dehumidifying and cooling mode, the cooling mode, or the MAX cooling mode is selected, an operation and a refrigerant flow are the same as those of the above embodiment (Embodiment 1). However, in this embodiment (Embodiment 2), the solenoid valve 80 is closed in these heating mode, dehumidifying and cooling mode, cooling mode and MAX cooling mode.(9) Dehumidifying and Heating Mode of Vehicle Air Conditioning Device 1 of FIG. 8On the other hand, in this embodiment (Embodiment 2), when the dehumidifying and heating mode is selected, the controller 32 opens a solenoid valve 21 (for heating) and closes a solenoid valve 17 (for cooling). In addition, the control device opens a solenoid valve 30 (for dehumidifying) and closes a solenoid valve 40 (for dehumidifying). In addition, the controller 32 opens the solenoid valve 80 (for dehumidifying). Then, the controller operates a compressor 2 and respective blowers 15 and 27, and an air mix damper reaches a state of sending all the air in the air flow passage 3 blown out from the indoor blower 27 and passed through a heat absorber 9 to an auxiliary heater 23 and the radiator 4.Consequently, a high-temperature high-pressure refrigerant gas discharged from the compressor 2 flows through the solenoid valve 30 and a refrigerant pipe 13G into the radiator 4. the air in the air flow passage 3 passes through the radiator 4, and thus the air in the air flow passage 3 is heated by the high-temperature refrigerant in the radiator 4, whereas the heat is taken from the refrigerant in the radiator 4 by the air and is cooled to condense and liquify.The refrigerant liquefied in the radiator 4 flows out from the radiator 4 and then flows through the refrigerant pipe 13E to reach the outdoor expansion valve 6. The refrigerant flowing into the outdoor expansion valve 6 is decompressed therein, and then flows into an outdoor heat exchanger 7, The refrigerant flowing into the outdoor heat exchanger 7 evaporates, and the heat is conveyed in from the outside air passed through by traveling or the outdoor blower 15. In other words, the refrigerant circuit R functions as a heat pump. Then, the low-temperature refrigerant flowing out from the outdoor heat exchanger 7 flows through a refrigerant pipe 13A, the solenoid valve 21, and a refrigerant pipe 13D, and flows from a refrigerant pipe 13C into an accumulator 12 to perform gas-liquid separation therein, and then the refrigerant gas is sucked into the compressor 2, and this circulation is repeated.Moreover, a part of the condensed refrigerant flowing through the radiator 4 and the refrigerant pipe 13E is dispersed, and this part of the refrigerant flows through the solenoid valve 80, a check valve 81, the second bypass pipe 83, the refrigerant pipe 13B, and an indoor heat exchanger 19 to reach the indoor expansion valve 8. The refrigerant is decompressed in the indoor expansion valve 8, and then flows into the heat absorber 9 to evaporate. By a heat absorbing operation at this time, water in the air blown out from the indoor blower 27 coagulates to adhere to the heat absorber 9, and thus the air is cooled and dehumidified.The refrigerant evaporated in the heat absorber 9 flows through the indoor heat exchanger 19 to join with the refrigerant from the refrigerant pipe 13D in the refrigerant pipe 13C, and then flows through the accumulator 12 to be sucked into the compressor 2, this circulation being repeated. The air dehumidified in the heat absorber 9 is reheated in a process of passing through the radiator 4, wherein the dehumidifying and heating of the vehicle interior is performed.The controller 32 controls a rotational speed of the compressor 2 on the basis of a high pressure of the refrigerant circuit R detected by a discharge pressure sensor 42 or a radiator pressure sensor 47, and controls a valve position of the outdoor expansion valve 6 on the basis of a temperature of the heat absorber 9 detected by a heat absorber temperature sensor 48.Also in the vehicle air-conditioning device 1 of this embodiment, the controller 32 performs an operation of judging a suspected refrigerant shortage and determining an occurrence of the refrigerant shortage as described in (7) and (8) above. Consequently, when a refrigerant gradually leaks from the refrigerant circuit R or when an amount of the refrigerant trapped in the refrigerant circuit R during operation or the like is small, it is possible to detect the occurrence of the refrigerant shortage early.Note that the controller in the embodiment compares an estimated refrigerant discharge temperature value Tdst and a refrigerant discharge temperature Td, or compares an estimated refrigerant discharge pressure value Pdst and a refrigerant discharge pressure Pd, thereby obtaining a difference between both of the temperatures or pressures. However, the present invention is not limited thereto. The controller may obtain as a result of comparing a ratio therebetween and judge the occurrence of refrigerant shortage of the refrigerant circuit R, for example, when the ratio Tdst / Td decreases or when the ratio Pdst / Pd increases.Moreover, in the embodiment, normal time data is a multiple regression equation in which the refrigerant discharge estimated temperature value Tdst is regarded as an auxiliary controlled variable and a refrigerant suction temperature Ts and the refrigerant discharge pressure Pd are regarded as explanatory variables, or the normal time data is a multiple regression equation in which the refrigerant discharge estimated pressure value Pdst is regarded as an auxiliary controlled variable and a refrigerant suction temperature Ts and the refrigerant discharge temperature Td are regarded as explanatory variables. However, the present invention is not limited thereto, and the normal time data may be an equation or mapping data indicating a ratio of the refrigerant suction temperature Ts and the refrigerant discharge pressure Pd to the refrigerant discharge temperature Td at a normal time when the refrigerant circuit is filled with a sufficient amount of the refrigerant, or an equation or mapping data indicating a ratio of the refrigerant suction temperature Ts and the refrigerant discharge temperature Td to the refrigerant discharge pressure Pd at the normal time when the refrigerant circuit is filled with the sufficient amount of the refrigerant. Also in this case, it is possible to accurately calculate the refrigerant discharge temperature estimated value Tdst or the refrigerant discharge pressure estimated value Pdst. Thus, the multiple regression equation is used as in the embodiment, so that it is possible to further accurately calculate the refrigerant discharge temperature estimated value Tdst or the refrigerant discharge pressure estimated value Pdst.In addition, the present invention has been described in the embodiment in the example in which the controller switches between the heating mode, the dehumidifying and heating mode, the dehumidifying and cooling mode, the cooling mode, and the MAX cooling mode, but the present invention is not limited thereto. The present invention is also effective for the vehicle air conditioning apparatus that performs either one or any combination of the operation modes.Moreover, the present invention is not limited to the switching control of the respective operation modes described in the embodiments, and appropriate conditions can be set by employing any one, any combination, or all of parameters such as the outside air temperature Tam, the humidity of the vehicle interior, the target outlet temperature TAO, the radiator temperature TH, the target radiator temperature TCO, the heat absorber temperature Te, the target heat absorber temperature TEO, and the presence / absence of the requirement for dehumidifying the vehicle interior according to the performance and the use environment of the vehicle air conditioning device.In addition, the auxiliary heater is not limited to the auxiliary heater 23 described in the embodiments, and a heating medium circulation circuit that circulates a heating medium heated by a heater to heat air in an air flow passage, a heater core that circulates cooling water heated by an internal combustion engine, or the like may be used. Moreover, the compositions of the refrigerant circuit R described in the above respective embodiments are not limited thereto, and the compositions are changeable without departing from the spirit of the present invention.Description of Reference Numerals1 Vehicle air conditioner 2 Compressor 3 Air flow passage 4 Radiator 6 Outdoor expansion valve (a pressure reducing unit) 7 Outdoor heat exchanger (a radiator or a heat absorber) 8 Indoor expansion valve (a pressure reducing unit) 9 Heat absorbers 17, 21, 30, and 40 Solenoid valve 23 Auxiliary heater (an auxiliary heater) 27 Indoor blower (a blower fan) 28 Air mix damper 32 Controller (a controller) 35 Bypass pipe 44 Suction pressure sensor 54 Outdoor heat exchanger temperature sensor 55 Suction temperature sensor R Refrigerant circuit

Claims

A vehicle air conditioning apparatus (1) comprising a refrigerant circuit (R) having a compressor (2) for compressing a refrigerant, a radiator (4) for radiating the refrigerant, a pressure reducing unit (6, 8), and a heat absorber (9) for letting the refrigerant absorb heat, thereby air conditioning air of a vehicle interior, wherein the vehicle air conditioning apparatus (1) comprises a controller (32) for controlling the compressor (2), wherein a normal time in which the refrigerant circuit (R) is filled with a sufficient amount of the refrigerant is defined, wherein the controller (32) has normal time data indicating a relationship between a refrigerant suction temperature Ts and a refrigerant discharge temperature Td of the compressor (2) to the normal time, The controller (32) is configured to calculate, from the normal time data based on the current refrigerant suction temperature Ts, a refrigerant discharge estimated temperature value Tdst that is an estimated value of the refrigerant discharge temperature Td at the normal time, and compare the refrigerant discharge estimated temperature value Tdst and the current refrigerant discharge temperature Td, thereby judging a refrigerant shortage of the refrigerant circuit (R).The vehicle air conditioning device (1) according to claim 1, wherein the normal time data is data indicating a ratio of the refrigerant suction temperature Ts and a refrigerant discharge pressure Pd of the compressor (2) to the refrigerant discharge temperature Td at the normal time.The vehicle air conditioning device (1) according to claim 1 or 2, wherein the normal time data is a multiple regression equation in which the refrigerant discharge temperature estimated value Tdst is regarded as an auxiliary controlled variable, and the refrigerant suction temperature Ts and the refrigerant discharge pressure Pd of the compressor (2) are regarded as explanatory variables.A vehicle air conditioning apparatus (1) comprising a refrigerant circuit (R) having a compressor (2) for compressing a refrigerant, a radiator (4) for radiating the refrigerant, a pressure reducing unit (6, 8), and a heat absorber (9) for letting the refrigerant absorb heat, thereby air conditioning air of a vehicle interior, wherein the vehicle air conditioning apparatus (1) comprises a controller (32) for controlling the compressor (2), wherein a normal time in which the refrigerant circuit (R) is filled with a sufficient amount of the refrigerant is defined, wherein the controller (32) has normal time data indicating a relationship between a refrigerant suction temperature Ts and a refrigerant discharge pressure Pd of the compressor at the normal time, The controller (32) is configured to calculate, from the normal time data, on the basis of the current refrigerant suction temperature Ts, an estimated refrigerant discharge pressure value Pdst that is an estimated value of the refrigerant discharge pressure Pd at the normal time, and compare the estimated refrigerant discharge pressure value Pdst and the current refrigerant discharge pressure Pd, thereby judging a refrigerant shortage of the refrigerant circuit (R).The vehicle air-conditioning device (1) according to claim 4, wherein the normal time data is data indicating a ratio of the refrigerant suction temperature Ts and a refrigerant discharge temperature Td of the compressor (2) to the refrigerant discharge pressure Pd at the normal time when the refrigerant circuit (R) is filled with the sufficient amount of the refrigerant.The vehicle air conditioning device (1) according to claim 4 or 5, wherein the normal time data is a multiple regression equation in which the refrigerant discharge pressure estimated value Pdst is regarded as an auxiliary controlled variable, and the refrigerant suction temperature Ts and the refrigerant discharge temperature Td of the compressor (2) are regarded as explanatory variables.The vehicle air-conditioning device (1) according to any one of claims 1 to 6, wherein when it is judged that there is a suspected refrigerant shortage of the refrigerant circuit (R), the control device (32) is configured to decrease a capacity of the compressor (2).The vehicle air-conditioning device (1) according to claim 7, wherein the controller (32) is configured to decrease the capacity of the compressor (2), and then determine an occurrence of the refrigerant shortage of the refrigerant circuit (R) over conditions that a difference between the refrigerant discharge estimated temperature value Tdst and the current refrigerant discharge temperature Td or a difference between the refrigerant discharge estimated pressure value Pdst and the current refrigerant discharge pressure Pd increases.The vehicle air conditioning device (1) according to any one of claims 1 to 6, wherein when it is judged that there is a suspected refrigerant shortage of the refrigerant circuit (R), the controller (32) is configured to restrict a used bandwidth of a rotational speed (NC) of the compressor (2), compare again the refrigerant discharge estimated temperature value Tdst and the refrigerant discharge current temperature Td in this state, or compare the refrigerant discharge estimated pressure value Pdst and the refrigerant discharge current pressure Pd, and determine the occurrence of the refrigerant shortage of the refrigerant circuit (R).The vehicle air-conditioning device (1) according to claim 9, wherein in a state where the used bandwidth of the rotational speed NC of the compressor (2) is limited, the controller (32) is configured to determine the occurrence of the refrigerant shortage of the refrigerant circuit (R) while a difference between the refrigerant discharge estimated temperature value Tdst and the current refrigerant discharge temperature Td or a difference between the refrigerant discharge estimated pressure value Pdst and the current refrigerant discharge pressure Pd is smaller.The vehicle air conditioning device (1) according to any one of claims 8 to 10, wherein when the occurrence of the refrigerant shortage of the refrigerant circuit (R) is determined, the controller (32) is configured to execute a predetermined notification operation.The vehicle air-conditioning device (1) according to any one of claims 8 to 11, wherein when the occurrence of the refrigerant shortage of the refrigerant circuit (R) is determined, the controller (32) is configured to decrease the rotational speed NC of the compressor (2) or stop the compressor.

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