JP5935714B2 - Refrigeration cycle equipment - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus applied to an air conditioner that cools and dehumidifies blown air blown into an air-conditioning target space and heats the dehumidified blown air.

  Conventionally, Patent Document 1 describes a refrigeration cycle configured to be switchable to a refrigerant circulation circuit in a dehumidifying and heating mode. In the refrigerant circulation circuit in the dehumidifying heating mode, the refrigerant discharged from the compressor is used as a first indoor heat exchanger, a first variable throttle valve, an outdoor heat exchanger, a second variable throttle valve, a second indoor heat exchanger, and a compressor. Cycle through the path.

  Further, in the dehumidifying heating mode, the throttle opening degree of the first variable throttle valve is increased and the throttle opening degree of the second variable throttle valve is reduced, whereby the refrigerant radiates heat to the outside air in the outdoor heat exchanger. The refrigerant absorbs heat in the two indoor heat exchanger.

Japanese Patent No. 4,196,681

  However, according to the above prior art, the throttle opening of the second variable throttle valve is increased in order to obtain a higher blowing temperature in the dehumidifying heating mode, but the refrigerant evaporation temperature in the second indoor heat exchanger is the frost limit temperature (freezing point). ) In order to prevent the occurrence of frost (frost formation) in the following, it is necessary to limit the flow rate of refrigerant (the number of rotations of the compressor), and as a result, the discharge temperature is limited.

  An object of this invention is to provide the refrigerating-cycle apparatus which can obtain higher blowing temperature in dehumidification heating mode in view of the said point.

In order to achieve the above object, the invention according to claim 1 or 2 ,
A compressor (11) for sucking and discharging refrigerant;
A radiator (12) that radiates heat of the refrigerant to the air blown to the air-conditioning target space;
A first depressurizing means (13) and a second depressurizing means (18) configured to change the throttle opening and depressurizing the refrigerant;
An outdoor heat exchanger (15) for exchanging heat between the refrigerant and the outside air;
An evaporator (16) for evaporating the refrigerant by exchanging heat between the refrigerant and the blown air;
Refrigerant in the order of the compressor (11), the radiator (12), the first pressure reducing means (13), the outdoor heat exchanger (15), the second pressure reducing means (18), the evaporator (16), and the compressor (11). A refrigerant circuit in the first dehumidifying and heating mode through which the air flows,
Refrigerant in the order of compressor (11), radiator (12), first decompression means (13), evaporator (16), second decompression means (18), outdoor heat exchanger (15), compressor (11) Switching means (14, 50) for switching between the refrigerant circuit in the second dehumidifying and heating mode in which the
In the first dehumidifying and heating mode and the second dehumidifying and heating mode, the first pressure reducing means (13) and the second pressure reducing means (18) are configured so that the refrigerant absorbs heat in the outdoor heat exchanger (15) and the evaporator (16). The throttle opening is adjusted.
In the invention according to claim 1,
The switching means (14, 50)
In the first dehumidifying and heating mode, the temperature difference (TO-TE) obtained by subtracting the refrigerant temperature (TE) in the evaporator (16) from the refrigerant temperature (TO) in the outdoor heat exchanger (15) is the first value (β1). The air temperature (TAV) is reduced from the target air temperature (TAO).
When the closed temperature difference (TAO-TAV) exceeds the second value (γ1), switch to the second dehumidifying heating mode,
In the second dehumidifying heating mode, a temperature difference (TE-TO) obtained by subtracting the refrigerant temperature (TO) in the outdoor heat exchanger (15) from the refrigerant temperature (TE) in the evaporator (16) is the third value (β2). The target air temperature (TAO) is reduced from the air temperature (TAV).
When the closed temperature difference (TAV−TAO) exceeds the fourth value (γ2), the mode is switched to the first dehumidifying heating mode.
In the invention according to claim 2,
The switching means (14, 50)
In the first dehumidifying and heating mode, the throttle opening degree (EVC) of the second pressure reducing means (18) exceeds the first value (δ1), and the blown air temperature (TAV) is set from the target blown temperature (TAO).
When the reduced temperature difference (TAO-TAV) exceeds the second value (γ1), switch to the second dehumidifying heating mode,
In the second dehumidifying and heating mode, the throttle opening (EVC) of the second decompression means (18) exceeds the third value (δ2), and the target blowing temperature (TAO) is calculated from the blowing air temperature (TAV).
When the reduced temperature difference (TAV−TAO) exceeds the fourth value (γ2), the first dehumidifying heating mode is switched .

  According to this, since the refrigerant absorbs heat in the outdoor heat exchanger (15) and the evaporator (16) in the first dehumidifying heating mode and the second dehumidifying heating mode, the refrigerant does not absorb heat in the outdoor heat exchanger (15). Compared with the case where heat is radiated to the outside air, the temperature of the blown-out air blown out from the radiator (12, 34) (blowing temperature) can be increased.

  Further, in the first dehumidifying and heating mode, the refrigerant flows in the order of the outdoor heat exchanger (15), the second decompression means (18), and the evaporator (16), whereas in the second dehumidifying and heating mode, the first dehumidifying and heating mode is performed. Contrary to the mode, the refrigerant flows in the order of the evaporator (16), the second decompression means (18), and the outdoor heat exchanger (15).

  For this reason, in the second dehumidifying heating mode, the throttle opening degree of the first pressure reducing means (13) is adjusted so that the refrigerant evaporation temperature in the evaporator (16) is equal to or higher than the frost limit temperature, and the second pressure reducing means (18 ) Can be reduced to increase the amount of heat absorbed by the outdoor heat exchanger (15), so that the frosting in the evaporator (16) can be prevented and the blowout higher than that in the first dehumidifying heating mode can be achieved. The temperature can be obtained.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is a whole block diagram of the vehicle air conditioner in 1st Embodiment. It is a flowchart which shows the flow of the control processing which the control apparatus of the vehicle air conditioner in 1st Embodiment performs. It is a Mollier diagram which shows the state of the refrigerant | coolant in the 1st mode of the 1st dehumidification heating mode in 1st Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant in the 2nd mode of the 1st dehumidification heating mode in 1st Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant in the 3rd mode of the 1st dehumidification heating mode in 1st Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant in the 4th mode of 1st dehumidification heating mode in 1st Embodiment, and the 1st mode of 2nd dehumidification heating mode. It is a Mollier diagram which shows the state of the refrigerant | coolant in the 2nd mode of the 2nd dehumidification heating mode in 1st Embodiment. It is a graph which shows the blowing air temperature adjustable range of the 1st dehumidification heating mode and 2nd dehumidification heating mode in 1st Embodiment. It is a flowchart which shows the flow of the control processing which the control apparatus of the vehicle air conditioner in 2nd Embodiment performs. It is a whole block diagram of the vehicle air conditioner in 3rd Embodiment.

  Hereinafter, embodiments will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are given the same reference numerals.

(First embodiment)
A first embodiment will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram of a vehicle air conditioner 1 according to the present embodiment.

  In this embodiment, the refrigeration cycle apparatus 10 of the present invention is applied to a vehicle air conditioner 1 for a hybrid vehicle that obtains a driving force for vehicle travel from an internal combustion engine (engine) and a travel electric motor. The refrigeration cycle apparatus 10 functions to cool or heat the vehicle interior air blown into the vehicle interior, which is the air conditioning target space, in the vehicle air conditioner 1.

  For this reason, the refrigeration cycle apparatus 10 heats the refrigerant flow path in the cooling mode (cooling operation) for cooling the vehicle interior, the refrigerant flow path in the dehumidification heating mode (dehumidification operation) for heating while dehumidifying the vehicle interior, and the vehicle interior. The refrigerant flow path in the heating mode (heating operation) can be switched.

  Further, in the refrigeration cycle apparatus 10, the refrigerant flow path can be switched between the first dehumidifying and heating mode that is normally performed and the second dehumidifying and heating mode that is performed when the outside air temperature is extremely low as the dehumidifying and heating mode. It is configured.

  In the refrigeration cycle apparatus 10 of the present embodiment, a normal chlorofluorocarbon refrigerant is used as the refrigerant, and a subcritical refrigeration cycle in which the pressure of the high-pressure refrigerant does not exceed the critical pressure of the refrigerant is configured. This refrigerant is mixed with refrigerating machine oil for lubricating the compressor 11, and a part of the refrigerating machine oil circulates in the cycle together with the refrigerant.

  The compressor 11 is disposed in the engine room of the vehicle, sucks the refrigerant in the refrigeration cycle apparatus 10, compresses it, and discharges it. The electric motor 11b is a fixed capacity type compression mechanism 11a having a fixed discharge capacity. It is an electric compressor driven by. Specifically, various compression mechanisms such as a scroll-type compression mechanism and a vane-type compression mechanism can be employed as the compression mechanism 11a.

  The operation (rotation speed) of the electric motor 11b is controlled by a control signal output from the control device 50, and either an AC motor or a DC motor may be adopted. And the refrigerant | coolant discharge capability of the compression mechanism 11a is changed by this rotation speed control. Therefore, in this embodiment, the electric motor 11b comprises the discharge capability change means of the compression mechanism 11a.

  The inlet side of the condenser 12 is connected to the discharge port side of the compressor 11. The condenser 12 is disposed in the casing 31 of the indoor air conditioning unit 30, dissipates the refrigerant discharged from the compressor 11 (high-pressure refrigerant), and heats the air blown in the vehicle interior that has passed through the evaporator 16. It is a vessel.

  The inlet side of the first expansion valve 13 (first decompression means) is connected to the outlet side of the condenser 12. The first expansion valve 13 is a decompression means for decompressing the refrigerant, and a valve body configured to be able to change the throttle opening, and an electric actuator including a stepping motor that changes the throttle opening by displacing the valve body. This is an electric variable aperture mechanism that is configured to include:

  The first expansion valve 13 is composed of a variable throttle mechanism with a fully open function that fully opens the throttle opening. That is, the first expansion valve 13 can prevent the refrigerant from depressurizing by fully opening the throttle opening. The operation of the first expansion valve 13 is controlled by a control signal output from the control device 50.

  A first inlet / outlet port of the four-way valve 14 is connected to the outlet side of the first expansion valve 13. The four-way valve 14 is an electric four-way valve whose operation is controlled by a control voltage output from the control device.

  One entrance / exit side of the outdoor heat exchanger 15 is connected to the second entrance / exit of the four-way valve 14. One inlet / outlet side of the evaporator 16 is connected to the third inlet / outlet of the four-way valve 14. The inlet side of the accumulator 17 is connected to the fourth inlet / outlet of the four-way valve 14.

  The four-way valve 14 is connected to the outlet side of the first expansion valve 13 and one inlet / outlet side of the outdoor heat exchanger 15, and simultaneously connects one inlet / outlet side of the evaporator 16 and the inlet side of the accumulator 17; And a function of switching the refrigerant flow path connecting the one inlet / outlet side of the outdoor heat exchanger 15 and the inlet side of the accumulator 17 at the same time as connecting the outlet side of the first expansion valve 13 and one inlet / outlet side of the evaporator 16. Fulfill.

  Therefore, the four-way valve 14 constitutes switching means (refrigerant flow path switching means) for switching the refrigerant flow path of the refrigerant circulating in the cycle.

  The outdoor heat exchanger 15 exchanges heat between the refrigerant circulating inside and the outside air blown from a blower fan (not shown). The outdoor heat exchanger 15 functions as an evaporator that evaporates the refrigerant and exerts an endothermic effect in the heating mode or the like, and functions as a radiator that radiates the refrigerant in the cooling mode or the like.

  One inlet / outlet side of the second expansion valve 18 (second decompression means) is connected to the other inlet / outlet side of the outdoor heat exchanger 15. The second expansion valve 18 is a decompression means for decompressing the refrigerant, and a valve body configured to be able to change the throttle opening, and an electric actuator including a stepping motor that changes the throttle opening by displacing the valve body. This is an electric variable aperture mechanism that is configured to include:

  The second expansion valve 18 is composed of a variable throttle mechanism with a fully open function that fully opens the throttle opening. That is, the second expansion valve 18 can prevent the refrigerant from depressurizing by fully opening the throttle opening. The operation of the second expansion valve 18 is controlled by a control signal output from the control device 50.

  The other inlet / outlet side of the evaporator 16 is connected to the other inlet / outlet side of the second expansion valve 18. The evaporator 16 is disposed in the casing 31 of the indoor air-conditioning unit 30 on the upstream side of the air flow in the passenger compartment of the condenser 12, and condenses the refrigerant that circulates in the cooling mode, the dehumidifying heating mode, and the like. This is an evaporator that cools the air blown in the passenger compartment by exchanging heat with the air blown into the passenger compartment before passing through the vessel 12 and evaporating it.

  A three-way valve 19 is connected between the other inlet / outlet side of the outdoor heat exchanger 15 and the second expansion valve 18. The three-way valve 19 includes a refrigerant flow path connecting the other inlet / outlet side of the outdoor heat exchanger 15 and the second expansion valve 18, the other inlet / outlet side of the outdoor heat exchanger 15, and a third inlet / outlet (evaporation) of the four-way valve 14. This is an electromagnetic valve that switches between the refrigerant flow path connecting the inlet / outlet on the container 16 side, and its operation is controlled by a control signal output from the control device.

  The accumulator 17 is a gas-liquid separator that separates the gas-liquid refrigerant flowing into the accumulator 17 and stores excess refrigerant in the cycle. The suction port side of the compressor 11 is connected to the gas phase refrigerant outlet of the accumulator 17. Accordingly, the accumulator 17 functions to prevent liquid phase refrigerant from being sucked into the compressor 11 and prevent liquid compression in the compressor 11.

  Next, the indoor air conditioning unit 30 will be described. The indoor air conditioning unit 30 is disposed inside the instrument panel (instrument panel) at the foremost part of the vehicle interior, and houses a blower 32, a condenser 12, an evaporator 16 and the like in a casing 31 that forms an outer shell thereof. It is.

  The casing 31 forms an air passage for the air blown into the passenger compartment, and is formed of a resin (for example, polypropylene) having a certain degree of elasticity and excellent in strength. An inside / outside air switching device 33 for switching and introducing vehicle interior air (inside air) and outside air is arranged on the most upstream side of the blown air flow in the casing 31.

  The inside / outside air switching device 33 is formed with an inside air introduction port for introducing inside air into the casing 31 and an outside air introduction port for introducing outside air. Furthermore, inside / outside air switching device 33 is provided with an inside / outside air switching door that continuously adjusts the opening area of the inside air introduction port and the outside air introduction port to change the air volume ratio between the inside air volume and the outside air volume. Has been.

  A blower 32 that blows air introduced through the inside / outside air switching device 33 toward the vehicle interior is disposed on the downstream side of the air flow of the inside / outside air switching device 33. The blower 32 is an electric blower that drives a centrifugal multiblade fan (sirocco fan) 32a by an electric motor 32b, and the number of rotations (air flow rate) is controlled by a control signal (control voltage) output from the control device 50. Is done. The centrifugal multiblade fan 32a functions as a blowing unit that blows air into the passenger compartment.

  On the downstream side of the air flow of the blower 32, the evaporator 16, the heater core 34, and the condenser 12 are arranged in this order with respect to the flow of the air blown into the vehicle interior. In other words, the evaporator 16 is disposed upstream of the condenser 12 and the heater core 34 in the flow direction of the air blown into the vehicle interior.

  Here, the heater core 34 is a heating heat exchanger (cooling water air heat exchanger) for exchanging heat between engine cooling water that outputs driving force for vehicle travel and vehicle interior blown air. In addition, the heater core 34 of this embodiment is arrange | positioned with respect to the condenser 12 in the flow direction upstream of the vehicle interior blowing air.

  In the casing 31, a cold air bypass passage 35 is formed in which the air that has passed through the evaporator 16 is caused to bypass the condenser 12 and the heater core 34.

  On the downstream side of the air flow of the evaporator 16 and the upstream side of the air flow of the condenser 12 and the heater core 34, of the air after passing through the evaporator 16, the air that passes through the condenser 12 and the air that passes through the cold air bypass passage 35. An air mix door 36 for adjusting the air volume ratio is disposed.

  A mixing space for mixing the air that has passed through the condenser 12 and the air that has passed through the cold air bypass passage 35 is provided on the downstream side of the air flow of the condenser 12 and the cold air bypass passage 35.

  A blower outlet (not shown) that blows the conditioned air mixed in the mixing space into the passenger compartment that is the air-conditioning target space is disposed on the most downstream side of the blast air flow in the casing 31. Specifically, as the air outlet, there are a face air outlet that blows air-conditioned air to the upper body of the passenger in the passenger compartment, a foot air outlet that blows air-conditioned air to the feet of the passenger, and a defroster that blows air-conditioned air toward the inner surface of the front window glass of the vehicle There is an air outlet.

  Therefore, the temperature of the conditioned air mixed in the mixing space is adjusted by adjusting the air volume ratio between the air passing through the condenser 12 and the heater core 34 and the air passing through the cold air bypass passage 35 by the air mix door 36. The temperature of the conditioned air blown out from each outlet is adjusted. The air mix door 36 is driven by a servo motor (not shown) that operates according to a control signal output from the control device 50.

  A face door (not shown) for adjusting the opening area of the face outlet and a foot door (not shown) for adjusting the opening area of the foot outlet are provided on the upstream side of the air flow of the face outlet, the foot outlet, and the defroster outlet. ) And a defroster door (not shown) for adjusting the opening area of the defroster outlet.

  These face doors, foot doors, and defroster doors constitute the outlet mode switching means for switching the outlet mode, and the operation thereof is performed by a control signal output from the control device 50 via a link mechanism or the like. It is driven by a controlled servo motor (not shown).

  Next, the electric control unit of this embodiment will be described. The control device 50 is composed of a well-known microcomputer including a CPU, ROM, RAM, and its peripheral circuits, and performs various calculations and processing based on a control program stored in the ROM, and is connected to the output side. Controls the operation of various control devices.

  On the input side of the control device 50, there are an inside air sensor that detects the vehicle interior temperature Tr, an outside air sensor that detects the outside air temperature Tam, a solar radiation sensor that detects the amount of solar radiation Ts in the vehicle interior, and the refrigerant temperature in the outdoor heat exchanger 15 (outdoor Outdoor heat exchanger temperature sensor 51 as an outdoor heat exchanger refrigerant temperature detecting means for detecting TO (heat exchanger temperature) TO, evaporator refrigerant temperature detecting means for detecting refrigerant temperature (evaporator temperature) TE in evaporator 16 Evaporator temperature sensor 52, discharge temperature sensor Td for detecting the temperature of the refrigerant discharged from the compressor 11, and blown air as blown temperature detecting means for detecting the blown air temperature (car blown air temperature) TAV blown into the vehicle compartment Various air conditioning control sensor groups such as a temperature sensor are connected.

  In the example of FIG. 1, a temperature sensor that detects the temperature of the refrigerant on the outlet side of the outdoor heat exchanger 15 is provided as the outdoor heat exchanger temperature sensor 51, and the surface temperature (fin temperature) of the evaporator 16 is provided as the evaporator temperature sensor 52. ) Is provided.

  As the outdoor heat exchanger temperature sensor 51, a temperature sensor that detects the surface temperature (fin temperature) of the outdoor heat exchanger 15 may be provided. As the evaporator temperature sensor 52, a temperature sensor that detects the temperature of the refrigerant on the outlet side of the evaporator 16 may be provided.

  An operation panel (not shown) disposed near the instrument panel in the front part of the vehicle interior is connected to the input side of the control device 50, and operation signals are input from various operation switches provided on the operation panel. As various operation switches provided on the operation panel, specifically, an air conditioner switch (A / C switch) for setting whether or not to cool the air blown in the vehicle interior by the indoor air conditioning unit 30, a setting in the vehicle interior A temperature setting switch for setting the temperature is provided.

  The control device 50 is configured such that control means for controlling the operation of various control devices connected to the output side is integrally configured, and the configuration (software and hardware) for controlling the operation of each control device is as follows. Control means for controlling the operation of each control device is configured.

  For example, the configuration for controlling the electric motor of the compressor 11 constitutes the discharge capacity control means, the configuration for controlling the first expansion valve 13 constitutes the first throttle control means, and the configuration for controlling the second expansion valve 18. The configuration that constitutes the second throttle control means and controls the four-way valve 14 constitutes the flow path switching control means.

  The configuration for controlling the four-way valve 14 in the control device 50 constitutes, together with the four-way valve 14, switching means (refrigerant flow switching means) for switching the refrigerant flow path of the refrigerant circulating in the cycle.

  Next, the operation of the vehicle air conditioner 1 of the present embodiment having the above configuration will be described. In the vehicle air conditioner 1 of the present embodiment, it is possible to switch to a cooling mode for cooling the passenger compartment, a heating mode for heating the passenger compartment, and a dehumidifying heating mode for heating while dehumidifying the passenger compartment.

  Switching control processing for each operation mode will be described with reference to FIG. FIG. 2 is a flowchart showing a flow of control processing executed by the control device 50 of the vehicle air conditioner 1 of the present embodiment. 2 is executed as a subroutine of a main routine of air conditioning control (not shown). Further, each control step in FIG. 2 constitutes various function realizing means possessed by the control device 50.

First, the control device 50 reads the detection signal of the sensor group and the operation signal of the operation panel (S10), and the target blowout that is the target temperature of the blowout air blown into the vehicle interior based on the read detection signal and operation signal values. The temperature TAO is calculated based on the following formula F1 (S20). Accordingly, the control step S20 of the present embodiment constitutes a target blowing temperature determining unit.
TAO = Kset × Tset−Kr × Tr−Kam × Tam−Ks × Ts + C (F1)
Note that Tset is the vehicle interior set temperature set by the temperature setting switch, Tr is the vehicle interior temperature (inside air temperature) detected by the inside air sensor, Tam is the outside air temperature detected by the outside air sensor, and Ts is detected by the solar radiation sensor. The amount of solar radiation. Kset, Kr, Kam, Ks are control gains, and C is a correction constant.

  Next, it is determined whether or not the A / C switch of the operation panel is turned on (S30). As a result, when it is determined that the A / C switch is off (S30: NO), the operation mode is determined to be a heating mode (non-cooling mode) in which the vehicle interior air is not cooled by the indoor air conditioning unit 30 ( S40) When it is determined that the A / C switch is on (S30: YES), the operation mode is either the cooling mode for cooling the air blown into the vehicle interior or the dehumidifying heating mode (cooling). Step S50 is entered to determine the mode.

  In step S50, it is determined whether or not the target outlet temperature TAO is lower than a predetermined cooling reference temperature α. As a result, when it is determined that the target outlet temperature TAO is lower than the cooling reference temperature α (S50: YES), the operation mode is determined to be the cooling mode in order to perform cooling of the passenger compartment (S60), When it is determined that the target outlet temperature TAO is equal to or higher than the cooling reference temperature α (S50: YES), the process proceeds to step S70.

  In step S70, a temperature difference (= TO−TE) obtained by subtracting the detected value of the evaporator temperature sensor (evaporator temperature TE) from the detected value of the outdoor heat exchanger temperature sensor (outdoor heat exchanger temperature TO) is predetermined. It is determined whether it is below a reference value β1 (hereinafter referred to as a threshold value β1). As a result, when the temperature difference between the outdoor heat exchanger temperature TO and the evaporator temperature TE is determined to be greater than or equal to the threshold value β1 (S70: NO), the temperature adjustable range of the blown air into the vehicle compartment is from the low temperature range. The first dehumidifying and heating mode, which is a normal dehumidifying and heating mode that is a wide range of the high temperature range, is determined (S80), and it is determined that the temperature difference between the outdoor heat exchanger temperature TO and the evaporator temperature TE is below the threshold value β1. If yes (S70: YES), the process proceeds to step S90.

  In step S90, a reference value γ1 (hereinafter referred to as a threshold value γ1) determined in advance is a temperature difference (= TAO−TAV) obtained by subtracting the detected value of the blown air temperature sensor (the vehicle cabin blown air temperature TAV) from the target blown temperature TAO. It is determined whether or not it exceeds.

  As a result of the determination process in step S90, when it is determined that the temperature difference between the target blowing temperature TAO and the vehicle interior blowing air temperature TAV is equal to or less than the threshold γ1 (S90: NO), the first dehumidifying heating mode is determined (S80). ), When it is determined that the temperature difference between the target blowing temperature TAO and the vehicle cabin blowing air temperature TAV exceeds the threshold value γ1 (S90: YES), the process proceeds to step S100.

  In step S100, it is determined whether or not a temperature difference (= TE−TO) obtained by subtracting the outdoor heat exchanger temperature TO from the evaporator temperature TE is lower than a predetermined reference value β2 (hereinafter referred to as a threshold value β2). . As a result, when it is determined that the temperature difference between the outdoor heat exchanger temperature TO and the evaporator temperature TE is equal to or greater than the threshold value β2 (S100: NO), the temperature adjustable range of the air blown into the vehicle interior is the first dehumidifying range. When it is determined that the second dehumidifying heating mode is higher than that in the heating mode (S110), and it is determined that the temperature difference between the outdoor heat exchanger temperature TO and the evaporator temperature TE is below the threshold β2 (S100) : YES), the process proceeds to step S120.

  In step S120, it is determined whether or not a temperature difference (= TAV−TAO) obtained by subtracting the target blowing temperature TAO from the vehicle cabin blowing air temperature TAV exceeds a predetermined reference value γ2 (hereinafter referred to as a threshold value γ2). .

  As a result of the determination processing in step S120, when it is determined that the temperature difference between the vehicle interior blown air temperature TAV and the target blowout temperature TAO exceeds the threshold γ2 (S120: YES), the first dehumidifying heating mode is determined. If it is determined that the temperature difference between the vehicle interior blown air temperature TAV and the target blowout temperature TAO is equal to or smaller than the threshold γ2 (S120: NO), the second dehumidifying heating mode is determined (S110).

  In this way, each operation mode can be appropriately switched between the heating mode, the cooling mode, the first dehumidifying heating mode, and the second dehumidifying heating mode according to the operating environment of the vehicle air conditioner 1.

  Next, operations in the cooling mode, the heating mode, the first dehumidifying heating mode, and the second dehumidifying heating mode will be described.

(A) Heating Mode In the heating mode, the control device 50 is connected to the outlet side of the first expansion valve 13 and one inlet / outlet side of the outdoor heat exchanger 15 by the four-way valve 14 and at the same time one outlet / inlet side of the evaporator 16. And the inlet side of the accumulator 17 are connected. Further, the control device 50 connects the other inlet / outlet side of the outdoor heat exchanger 15 and the third inlet / outlet of the four-way valve 14 (the inlet / outlet on the evaporator 16 side) at the three-way valve 19. Thereby, in the refrigerating cycle apparatus 10, it switches to the refrigerant circuit through which a refrigerant | coolant flows as shown by the white oblique line arrow of FIG.

  With the configuration of the refrigerant circuit, the control device 50 operates the control devices connected to the control device 50 based on the target blowing temperature TAO, the detection signal of the sensor group, and the like (control signals output to the various control devices). To decide.

  For example, the refrigerant discharge capacity of the compressor 11, that is, the control signal output to the electric motor 11b of the compressor 11 is determined as follows. First, the target condenser temperature TCO of the condenser 12 is determined on the basis of the target outlet temperature TAO with reference to a control map stored in the controller 50 in advance.

  Then, based on the deviation between the target condenser temperature TCO and the detected value of the discharge temperature sensor, the compressor 11 uses a feedback control method so that the temperature of the air blown into the passenger compartment approaches the target air temperature TAO. The control signal output to the electric motor 11b is determined.

  With respect to the control signal output to the first expansion valve 13, the target supercooling predetermined so that the degree of supercooling of the refrigerant flowing into the first expansion valve 13 is close to the maximum coefficient of performance (COP) of the cycle. Determined to approach the degree.

  Regarding the control signal output to the servo motor of the air mix door 36, the air mix door 36 closes the cold air bypass passage 35, and the total flow rate of the blown air after passing through the evaporator 16 is the air of the heater core 34 and the condenser 12. It is determined to pass through the passage.

  Then, the control signal determined as described above is output to various control devices. Thereafter, until the operation stop of the vehicle air conditioner 1 is requested by the operation panel, a control routine such as operation mode determination processing → determination of operation states of various control devices → output of control signals and the like is repeated at predetermined intervals. . Such a control routine is repeated in the other operation modes.

  Therefore, in the refrigeration cycle apparatus 10 in the heating mode, the high-pressure refrigerant discharged from the compressor 11 flows into the condenser 12. The refrigerant that has flowed into the condenser 12 exchanges heat with the air blown from the blower 32 and passes through the evaporator 16 to dissipate heat. Thereby, vehicle interior blowing air is heated.

  The refrigerant flowing out of the condenser 12 flows into the first expansion valve 13 and is decompressed and expanded at the first expansion valve 13 until it becomes a low-pressure refrigerant. The low-pressure refrigerant decompressed by the first expansion valve 13 flows into the outdoor heat exchanger 15 and absorbs heat from the outside air blown from the blower fan. The refrigerant flowing out of the outdoor heat exchanger 15 bypasses the second expansion valve 18 and the evaporator 16, flows into the accumulator 17, and is separated into gas and liquid.

  The vapor phase refrigerant separated by the accumulator 17 is sucked from the suction side of the compressor 11 and compressed again by the compressor 11. In addition, the liquid phase refrigerant | coolant isolate | separated by the accumulator 17 is stored in the inside of the accumulator 17 as a surplus refrigerant | coolant which is not required in order to exhibit the refrigerating capacity for which the cycle is requested | required.

  As described above, in the heating mode, the heat of the high-pressure refrigerant discharged from the compressor 11 by the condenser 12 is radiated to the vehicle interior blown air, and the heat of the cooling water is heated by the heater core 34 to the vehicle interior blown air. It is possible to dissipate heat and blow out the heated air in the vehicle interior to the vehicle interior. Thereby, heating of a vehicle interior is realizable.

(B) Cooling Mode In the cooling mode, the control device 50 is connected to the outlet side of the first expansion valve 13 and one inlet / outlet side of the outdoor heat exchanger 15 by the four-way valve 14 and at the same time one outlet side of the evaporator 16. And the inlet side of the accumulator 17 are connected. The control device 50 connects the other inlet / outlet side of the outdoor heat exchanger 15 and the second expansion valve 18 with the three-way valve 19. Further, the throttle opening of the first expansion valve 13 is set to a fully open state. Thereby, the refrigerating cycle apparatus 10 is switched to the refrigerant circuit through which a refrigerant flows as shown by the white arrow in FIG.

  With the configuration of the refrigerant circuit, the control device 50 operates the control devices connected to the control device 50 based on the target blowing temperature TAO, the detection signal of the sensor group, and the like (control signals output to the various control devices). To decide.

  For example, the refrigerant discharge capacity of the compressor 11, that is, the control signal output to the electric motor 11b of the compressor 11 is determined as follows. First, based on the target blowing temperature TAO, a target evaporator blowing temperature TEO of the blown air blown from the evaporator 16 is determined with reference to a control map stored in the control device 50 in advance.

  Based on the deviation between the target evaporator outlet temperature TEO and the detected value of the evaporator temperature sensor, the feedback control method is used to compress the temperature of the air that has passed through the evaporator 16 so as to approach the target outlet temperature TAO. A control signal output to the electric motor 11b of the machine 11 is determined.

  With respect to the control signal output to the second expansion valve 18, the target supercooling predetermined so that the degree of supercooling of the refrigerant flowing into the second expansion valve 18 approaches the maximum coefficient of performance (COP) of the cycle. Determined to approach the degree.

  Regarding the control signal output to the servo motor of the air mix door 36, the air mix door 36 closes the air passages of the heater core 34 and the condenser 12, and the total flow rate of the blown air after passing through the evaporator 16 is the cold air bypass passage. 35 is determined to pass.

  Therefore, in the refrigeration cycle apparatus 10 in the cooling mode, the high-pressure refrigerant discharged from the compressor 11 flows into the condenser 12. At this time, since the air mix door 36 closes the air passages of the heater core 34 and the condenser 12, the refrigerant that has flowed into the condenser 12 flows out of the condenser 12 without substantially exchanging heat with the air blown into the passenger compartment. To do.

  The refrigerant that has flowed out of the condenser 12 flows into the first expansion valve 13. At this time, since the throttle opening of the first expansion valve 13 is fully opened, the refrigerant flowing out of the condenser 12 flows into the outdoor heat exchanger 15 without being depressurized by the first expansion valve 13. The refrigerant flowing into the outdoor heat exchanger 15 radiates heat to the outside air blown from the blower fan in the outdoor heat exchanger 15.

  The refrigerant flowing out of the outdoor heat exchanger 15 flows into the second expansion valve 18 and is decompressed and expanded at the second expansion valve 18 until it becomes a low-pressure refrigerant. The low-pressure refrigerant decompressed by the second expansion valve 18 flows into the evaporator 16, absorbs heat from the air blown from the vehicle interior blown from the blower 32, and evaporates. Thereby, vehicle interior blowing air is cooled.

  The refrigerant flowing out of the evaporator 16 flows into the accumulator 17 and is separated into gas and liquid. The vapor phase refrigerant separated by the accumulator 17 is sucked from the suction side of the compressor 11 and compressed again by the compressor 11. In addition, the liquid phase refrigerant | coolant isolate | separated by the accumulator 17 is stored in the inside of the accumulator 17 as a surplus refrigerant | coolant which is not required in order to exhibit the refrigerating capacity for which the cycle is requested | required.

  As described above, in the cooling mode, the air mix door 36 closes the air passages of the heater core 34 and the condenser 12, so that the air blown into the vehicle interior cooled by the evaporator 16 can be blown out into the vehicle interior. . Thereby, cooling of a vehicle interior is realizable.

(C) First Dehumidifying Heating Mode In the first dehumidifying heating mode, the controller 50 is connected to the outlet side of the first expansion valve 13 and the one inlet / outlet side of the outdoor heat exchanger 15 by the four-way valve 14 at the same time. Is connected to the inlet side of the accumulator 17. The control device 50 connects the other inlet / outlet side of the outdoor heat exchanger 15 and the second expansion valve 18 with the three-way valve 19. Further, the first and second expansion valves 13 and 18 are set to the throttled state or fully opened state. Thereby, the refrigerating cycle apparatus 10 is switched to the refrigerant circuit through which a refrigerant flows as shown by the white arrow in FIG. 1 similarly to the cooling mode. In the first dehumidifying and heating mode (first refrigerant flow path), the refrigerant flows in the order of the outdoor heat exchanger 15, the second expansion valve 18, and the evaporator 16.

  With the configuration of the refrigerant circuit, the control device 50 operates the control devices connected to the control device 50 based on the target blowing temperature TAO, the detection signal of the sensor group, and the like (control signals output to the various control devices). To decide.

  For example, the control signal output to the electric motor 11b of the compressor 11 is determined similarly to the cooling mode. Regarding the control signal output to the servo motor of the air mix door 36, the air mix door 36 closes the cold air bypass passage 35, and the total flow rate of the blown air after passing through the evaporator 16 is the heater core 34 and the condenser 12. To pass through the air passage.

  Further, the first expansion valve 13 and the second expansion valve 18 are changed according to a target blowing temperature TAO that is a target temperature of the blowing air blown into the vehicle interior. Specifically, the control device 50 decreases the throttle opening of the first expansion valve 13 and increases the second expansion valve 18 as the target blowing temperature TAO, which is the target temperature of the blowing air blown into the passenger compartment, increases. Increase the throttle opening. Thereby, in the 1st dehumidification heating mode, the mode of four steps from the 1st mode to the 4th mode is performed.

(C-1) 1st mode 1st mode is performed when the target blowing temperature TAO becomes more than the cooling reference temperature (alpha) and below the predetermined 1st reference temperature at the time of 1st dehumidification heating mode.

  In the first mode, the throttle opening of the first expansion valve 13 is fully opened, and the second expansion valve 18 is in the throttle state. Accordingly, the cycle configuration (refrigerant flow path) is the same refrigerant flow path as in the cooling mode, but the air mix door 36 fully opens the air passage on the condenser 12 and heater core 34 side, so that the cycle is circulated. The state of the refrigerant changes as shown in the Mollier diagram of FIG.

  That is, as shown in FIG. 3, the high-pressure refrigerant (point a1) discharged from the compressor 11 flows into the condenser 12 and is heat-exchanged with the vehicle interior blown air cooled and dehumidified by the evaporator 16. To dissipate heat (point a1 → point a2 in FIG. 3). Thereby, vehicle interior blowing air is heated.

  The refrigerant that has flowed out of the condenser 12 flows into the first expansion valve 13. At this time, since the throttle opening of the first expansion valve 13 is fully opened, the refrigerant flowing out of the condenser 12 flows into the outdoor heat exchanger 15 without being depressurized by the first expansion valve 13. The refrigerant flowing into the outdoor heat exchanger 15 dissipates heat to the outside air blown from the blower fan in the outdoor heat exchanger 15 (point a2 → point a3 in FIG. 3).

  The refrigerant that has flowed out of the outdoor heat exchanger 15 flows into the second expansion valve 18 and is decompressed and expanded at the second expansion valve 18 until it becomes a low-pressure refrigerant (point a3 → a4 in FIG. 3). The low-pressure refrigerant decompressed by the second expansion valve 18 flows into the evaporator 16 and evaporates by absorbing heat from the air blown from the vehicle interior blown from the blower 32 (point a4 → a5 in FIG. 3). Thereby, vehicle interior blowing air is cooled. Then, the refrigerant that has flowed out of the evaporator 16 flows from the accumulator 17 to the suction side of the compressor 11 and is compressed again by the compressor 11 as in the cooling mode.

  As described above, in the first mode of the first dehumidifying and heating mode, the vehicle interior air cooled and dehumidified by the evaporator 16 can be heated by the heater core 34 and the condenser 12 and blown out into the vehicle interior. Thereby, dehumidification heating of a vehicle interior is realizable.

  In FIG. 3, the pressure P <b> 1 is the refrigerant pressure (frost limit pressure) in the evaporator 16 when the refrigerant evaporation temperature in the evaporator 16 reaches the frost limit temperature. In the first mode, the rotation speed of the compressor 11 is determined so that the refrigerant pressure in the evaporator 16 does not fall below the frost limit pressure P1.

(C-2) Second Mode The second mode is executed when the target outlet temperature TAO is higher than the first reference temperature and lower than or equal to a predetermined second reference temperature in the first dehumidifying and heating mode. In the second mode, the first expansion valve 13 is set to the throttle state, and the throttle opening of the second expansion valve 18 is set to the throttle state increased from that in the first mode. Therefore, in the second mode, the state of the refrigerant circulating in the cycle changes as shown in the Mollier diagram of FIG.

  That is, as shown in FIG. 4, the high-pressure refrigerant (point b1) discharged from the compressor 11 flows into the condenser 12 and is heat-exchanged with the vehicle interior blown air cooled and dehumidified by the evaporator 16. To dissipate heat (b1 point → b2 point in FIG. 4). Thereby, vehicle interior blowing air is heated.

  The refrigerant flowing out of the condenser 12 flows into the first expansion valve 13 and is depressurized until it becomes an intermediate pressure refrigerant (b2 point → b3 point in FIG. 4). Then, the intermediate pressure refrigerant decompressed by the first expansion valve 13 flows into the outdoor heat exchanger 15 and radiates heat to the outside air blown from the blower fan (b3 point → b4 point in FIG. 4).

  The refrigerant that has flowed out of the outdoor heat exchanger 15 flows into the second expansion valve 18 and is decompressed and expanded at the second expansion valve 18 until it becomes low-pressure refrigerant (b4 point → b5 point in FIG. 4). The low-pressure refrigerant decompressed by the second expansion valve 18 flows into the evaporator 16 and evaporates by absorbing heat from the air blown from the vehicle interior blown from the blower 32 (b5 point → b6 point in FIG. 4). Thereby, vehicle interior blowing air is cooled. Then, the refrigerant that has flowed out of the evaporator 16 flows from the accumulator 17 to the suction side of the compressor 11 and is compressed again by the compressor 11 as in the cooling mode.

  As described above, during the second mode of the first dehumidifying and heating mode, the vehicle interior air cooled and dehumidified by the evaporator 16 is heated by the condenser 12 and blown out into the vehicle interior, as in the first mode. be able to. Thereby, dehumidification heating of a vehicle interior is realizable.

  At this time, in the second mode, since the first expansion valve 13 is in the throttle state, the temperature of the refrigerant flowing into the outdoor heat exchanger 15 can be lowered compared to the first mode. Therefore, the temperature difference between the refrigerant temperature and the outside air temperature in the outdoor heat exchanger 15 can be reduced, and the heat radiation amount of the refrigerant in the outdoor heat exchanger 15 can be reduced.

  As a result, the heat release amount of the refrigerant in the condenser 12 can be increased with respect to the first mode, and the temperature of the blown air blown out from the condenser 12 can be increased as compared with the first mode.

  In the second mode, the rotation speed of the compressor 11 is determined so that the refrigerant pressure in the evaporator 16 does not fall below the frost limit pressure P1.

(C-3) Third Mode The third mode is executed when the target blowing temperature TAO is higher than the second reference temperature and lower than or equal to a predetermined third reference temperature in the first dehumidifying heating mode. In the third mode, a throttle state in which the throttle opening of the first expansion valve 13 is reduced compared to that in the second mode, and a throttle state in which the throttle opening of the second expansion valve 18 is increased than in the second mode; To do. Therefore, in the third mode, the state of the refrigerant circulating in the cycle changes as shown in the Mollier diagram of FIG.

  That is, as shown in FIG. 5, the high-pressure refrigerant (point c1) discharged from the compressor 11 flows into the condenser 12 and is heat-exchanged with the vehicle interior blown air cooled and dehumidified by the evaporator 16. To dissipate heat (point c1 → point c2 in FIG. 5). Thereby, vehicle interior blowing air is heated.

  The refrigerant flowing out of the condenser 12 flows into the first expansion valve 13 and is depressurized until it becomes an intermediate pressure refrigerant having a temperature lower than the outside air temperature (point c2 → point c3 in FIG. 5). Then, the intermediate pressure refrigerant decompressed by the first expansion valve 13 flows into the outdoor heat exchanger 15 and absorbs heat from the outside air blown from the blower fan (point c3 → point c4 in FIG. 5).

  The refrigerant that has flowed out of the outdoor heat exchanger 15 flows into the second expansion valve 18 and is decompressed and expanded at the second expansion valve 18 until it becomes a low-pressure refrigerant (point c4 → c5 in FIG. 5). The low-pressure refrigerant decompressed by the second expansion valve 18 flows into the evaporator 16 and absorbs heat from the air blown from the vehicle interior blown from the blower 32 to evaporate (point c5 → c6 in FIG. 5). Thereby, vehicle interior blowing air is cooled. Then, the refrigerant that has flowed out of the evaporator 16 flows from the accumulator 17 to the suction side of the compressor 11 and is compressed again by the compressor 11 as in the cooling mode.

  As described above, in the third mode of the first dehumidifying and heating mode, the vehicle interior air cooled and dehumidified by the evaporator 16 is heated by the condenser 12 in the same manner as in the first and second modes. Can be blown into the room. Thereby, dehumidification heating of a vehicle interior is realizable.

  At this time, in the third mode, the outdoor heat exchanger 15 is caused to function as a heat absorber (evaporator) by increasing the throttle opening of the second expansion valve 18, and therefore the condenser 12 than in the second mode. The temperature blown out from can be raised.

  As a result, the heat release amount of the refrigerant in the condenser 12 can be increased with respect to the second mode, and the temperature of the blown air blown out of the condenser 12 can be increased as compared with the second mode.

  In the third mode, the rotation speed of the compressor 11 is determined so that the refrigerant pressure in the evaporator 16 does not fall below the frost limit pressure P1.

(C-4) 4th mode 4th mode is performed when the target blowing temperature TAO becomes higher than 3rd reference temperature at the time of 1st dehumidification heating mode. In the fourth mode, the throttle opening of the first expansion valve 13 is set to a throttle state in which the throttle opening is reduced compared to that in the third mode, and the throttle opening of the second expansion valve 18 is set to a fully open state. Therefore, in the fourth mode, the state of the refrigerant circulating in the cycle changes as shown in the Mollier diagram of FIG.

  That is, as shown in FIG. 6, the high-pressure refrigerant (point d1) discharged from the compressor 11 flows into the condenser 12 and is heat-exchanged with the vehicle interior blown air cooled and dehumidified by the evaporator 16. To dissipate heat (point d1 → point d2 in FIG. 6). Thereby, vehicle interior blowing air is heated.

  The refrigerant flowing out of the condenser 12 flows into the first expansion valve 13 and is depressurized until it becomes a low-pressure refrigerant (point d2 → point d3 in FIG. 6). And the low-pressure refrigerant decompressed by the first expansion valve 13 flows into the outdoor heat exchanger 15 and absorbs heat from the outside air blown from the blower fan (point d3 → point d4 in FIG. 6).

  The refrigerant that has flowed out of the outdoor heat exchanger 15 flows into the second expansion valve 18. At this time, since the throttle opening of the second expansion valve 18 is fully opened, the refrigerant flowing out of the outdoor heat exchanger 15 flows into the evaporator 16 without being depressurized by the second expansion valve 18.

  The low-pressure refrigerant that has flowed into the evaporator 16 absorbs heat from the air blown from the passenger compartment blown from the blower 32 and evaporates (point d4 → point d5 in FIG. 6). Thereby, vehicle interior blowing air is cooled. Then, the refrigerant that has flowed out of the evaporator 16 flows from the accumulator 17 to the suction side of the compressor 11 and is compressed again by the compressor 11 as in the cooling mode.

  As described above, in the fourth mode of the first dehumidifying and heating mode, the vehicle interior air cooled and dehumidified by the evaporator 16 is heated by the condenser 12 in the same manner as in the first to third modes. Can be blown into the room. Thereby, dehumidification heating of a vehicle interior is realizable.

  At this time, in the fourth mode, as in the third mode, the outdoor heat exchanger 15 can function as a heat absorber (evaporator), and the throttle opening of the second expansion valve 18 can be made larger than that in the third mode. Since it is increased (fully opened), the refrigerant evaporation temperature in the outdoor heat exchanger 15 can be lowered. Therefore, the temperature difference between the refrigerant temperature and the outside air temperature in the outdoor heat exchanger 15 can be increased more than in the third mode, and the heat absorption amount of the refrigerant in the outdoor heat exchanger 15 can be increased.

  As a result, the heat release amount of the refrigerant in the condenser 12 can be increased with respect to the third mode, and the temperature of the blown air blown out of the condenser 12 can be increased as compared with the third mode.

  In the fourth mode, the rotation speed of the compressor 11 is determined so that the refrigerant pressure in the evaporator 16 does not fall below the frost limit pressure P1.

  As described above, in the first to fourth modes of the first dehumidifying and heating mode, the throttle opening degree of the first expansion valve 13 and the second expansion valve 18 is changed according to the target blowing temperature TAO to blow into the vehicle interior. The temperature of the blown air can be adjusted over a wide range from a low temperature range to a high temperature range.

  In other words, in the first dehumidifying and heating mode, while switching the outdoor heat exchanger 15 from a state where it functions as a radiator that radiates the refrigerant to a state where it functions as an evaporator that absorbs heat from the refrigerant, the refrigerant in the outdoor heat exchanger 15 is changed. The amount of heat release or the amount of heat absorption can be adjusted.

  Therefore, the heat radiation amount of the refrigerant in the condenser 12 can be adjusted in a wider range than the cycle configuration in which the outdoor heat exchanger 15 functions as either a radiator or an evaporator, and the air conditioning target space can be adjusted during the dehumidifying operation. The temperature adjustment range of the blown air that is blown out can be expanded.

(D) Second Dehumidifying Heating Mode In the second dehumidifying heating mode, the control device 50 connects the outlet side of the first expansion valve 13 and one outlet side of the evaporator 16 at the four-way valve 14 and at the same time the outdoor heat exchanger. One entrance / exit side of 15 and the entrance side of the accumulator 17 are connected. The control device 50 connects the other inlet / outlet side of the outdoor heat exchanger 15 and the second expansion valve 18 with the three-way valve 19. Further, the first and second expansion valves 13 and 18 are set to the throttled state or fully opened state. Accordingly, the refrigeration cycle apparatus 10 is switched to the second refrigerant flow path through which the refrigerant flows as indicated by the black arrow in FIG. In the second dehumidifying and heating mode (second refrigerant flow path), the evaporator 16, the second expansion valve 18, and the outdoor heat exchanger 15 are arranged in this order, contrary to the first dehumidifying and heating mode (first refrigerant flow path). The refrigerant will flow.

  With this refrigerant flow path configuration, the control device 50 operates various control devices connected to the control device 50 based on the target blowing temperature TAO, the detection signal of the sensor group, etc. (control signals output to the various control devices) ).

  For example, the control signal output to the electric motor 11b of the compressor 11 is determined similarly to the cooling mode. Regarding the control signal output to the servo motor of the air mix door 36, the air mix door 36 closes the cold air bypass passage 35, and the total flow rate of the blown air after passing through the evaporator 16 is the heater core 34 and the condenser 12. To pass through the air passage.

  Further, the first expansion valve 13 and the second expansion valve 18 are changed according to a target blowing temperature TAO that is a target temperature of the blowing air blown into the vehicle interior. Specifically, the control device 50 increases the throttle opening of the first expansion valve 13 and the second expansion valve 18 as the target blowing temperature TAO, which is the target temperature of the blowing air blown into the passenger compartment, increases. Reduce the throttle opening. Thereby, in 2nd dehumidification heating mode, the two-step mode from 1st mode to 2nd mode is performed.

(D-1) 1st mode 1st mode is performed when the target blowing temperature TAO becomes higher than 4th reference temperature at the time of 2nd dehumidification heating mode. In the first mode, the throttle opening of the first expansion valve 13 is the same as that in the fourth mode of the first dehumidifying and heating mode, and the throttle opening of the second expansion valve 18 is fully opened. Therefore, in the first mode, the state of the refrigerant circulating in the cycle changes as shown in the Mollier diagram of FIG.

  That is, as shown in FIG. 6, the high-pressure refrigerant (point d1) discharged from the compressor 11 flows into the condenser 12 and is heat-exchanged with the vehicle interior blown air cooled and dehumidified by the evaporator 16. To dissipate heat (point d1 → point d2 in FIG. 6). Thereby, vehicle interior blowing air is heated.

  The refrigerant flowing out of the condenser 12 flows into the first expansion valve 13 and is depressurized until it becomes a low-pressure refrigerant (point d2 → point d3 in FIG. 6). The low-pressure refrigerant decompressed by the first expansion valve 13 flows into the evaporator 16 and absorbs heat from the air blown from the vehicle interior blown from the blower 32 to evaporate (point d3 → d4 in FIG. 6). . Thereby, vehicle interior blowing air is cooled.

  The refrigerant that has flowed out of the evaporator 16 flows into the second expansion valve 18. At this time, since the throttle opening of the second expansion valve 18 is fully opened, the refrigerant flowing out of the evaporator 16 flows into the outdoor heat exchanger 15 without being depressurized by the second expansion valve 18.

  The low-pressure refrigerant flowing into the outdoor heat exchanger 15 absorbs heat from the outside air blown from the blower fan (point d4 → point d5 in FIG. 6). Then, the refrigerant that has flowed out of the outdoor heat exchanger 15 flows from the accumulator 17 to the suction side of the compressor 11 and is compressed again by the compressor 11 as in the cooling mode.

  As described above, in the first mode of the second dehumidifying and heating mode, the vehicle interior blown air cooled and dehumidified by the evaporator 16 is heated by the heater core 34 and the condenser 12 as in the first dehumidifying and heating mode. Can be blown into the passenger compartment. Thereby, dehumidification heating of a vehicle interior is realizable.

  At this time, in the first mode, the outdoor heat exchanger 15 can function as a heat absorber (evaporator) as in the fourth mode of the first dehumidifying and heating mode, and the third mode of the first dehumidifying and heating mode. Since the throttle opening of the first expansion valve 13 is further reduced, the refrigerant evaporation temperature in the outdoor heat exchanger 15 can be lowered. Therefore, the temperature difference between the refrigerant temperature and the outside air temperature in the outdoor heat exchanger 15 can be increased more than in the third mode of the first dehumidifying and heating mode, and the heat absorption amount of the refrigerant in the outdoor heat exchanger 15 can be increased. .

  As a result, compared with the third mode of the first dehumidifying and heating mode, the heat release amount of the refrigerant in the condenser 12 can be increased, and the blowout blown out from the condenser 12 compared to the third mode of the first dehumidifying and heating mode. The temperature of the air can be raised. That is, the temperature of the blown-out air blown out from the condenser 12 can be raised as in the fourth mode of the first dehumidifying and heating mode.

  In the first mode, the rotation speed of the compressor 11 is determined so that the refrigerant pressure in the evaporator 16 does not fall below the frost limit pressure P1.

(D-2) 2nd mode 2nd mode is performed when the target blowing temperature TAO becomes higher than 5th reference temperature at the time of 2nd dehumidification heating mode. In the second mode, the throttle opening of the first expansion valve 13 is made equal to or increased compared to that in the first mode, and the second expansion valve 18 is brought into the throttle state. Therefore, in the second mode, the state of the refrigerant circulating in the cycle changes as shown in the Mollier diagram of FIG.

  That is, as shown in FIG. 7, the high-pressure refrigerant (point e1) discharged from the compressor 11 flows into the condenser 12 and is heat-exchanged with the vehicle interior blowing air cooled and dehumidified by the evaporator 16. To dissipate heat (point e1 → point e2 in FIG. 7). Thereby, vehicle interior blowing air is heated.

  The refrigerant that has flowed out of the condenser 12 flows into the first expansion valve 13 and is depressurized until it becomes an intermediate-pressure refrigerant having a lower temperature than the air blown from the blower 32 (point e2 → e3 in FIG. 7). point). Then, the intermediate pressure refrigerant decompressed by the first expansion valve 13 flows into the evaporator 16, absorbs heat from the air blown from the vehicle interior blown from the blower 32 and evaporates (point e 3 → point e 4 in FIG. 7). ). Thereby, vehicle interior blowing air is cooled.

The refrigerant that has flowed out of the evaporator 16 flows into the second expansion valve 18 and is decompressed and expanded at the second expansion valve 18 until it becomes a low-pressure refrigerant (point e4 → point e5 in FIG. 7). The low-pressure refrigerant decompressed by the second expansion valve 18 flows into the outdoor heat exchanger 15, absorbs heat from the outside air blown from the blower fan, and evaporates (point e5 → point e6 in FIG. 7).
Then, the refrigerant that has flowed out of the evaporator 16 flows from the accumulator 17 to the suction side of the compressor 11 and is compressed again by the compressor 11 as in the cooling mode.

  As described above, in the second mode of the second dehumidifying and heating mode, the vehicle interior blown air cooled and dehumidified by the evaporator 16 is heated by the heater core 34 and the condenser 12 as in the first mode. Can be blown into the room. Thereby, dehumidification heating of a vehicle interior is realizable.

  At this time, in the second mode, as in the first mode, the outdoor heat exchanger 15 can be made to function as a heat absorber (evaporator), and the throttle opening of the second expansion valve 18 can be made larger than that in the first mode. Since it is reduced, the refrigerant evaporation temperature in the outdoor heat exchanger 15 can be lowered. Therefore, the temperature difference between the refrigerant temperature and the outside air temperature in the outdoor heat exchanger 15 can be increased more than in the first mode, and the heat absorption amount of the refrigerant in the outdoor heat exchanger 15 can be increased.

  As a result, the heat radiation amount of the refrigerant in the condenser 12 can be increased with respect to the first mode, and the temperature of the blown air blown out from the condenser 12 can be increased as compared with the first mode.

  In the second mode, the rotation speed of the compressor 11 is determined so that the refrigerant pressure in the evaporator 16 does not fall below the frost limit pressure P1.

  As described above, in the second dehumidifying and heating mode, the outdoor heat exchanger 15 is located downstream of the refrigerant flow with respect to the evaporator 16, contrary to the first dehumidifying and heating mode, so that the refrigerant evaporation temperature in the evaporator 16 is frosted. The refrigerant evaporation temperature in the outdoor heat exchanger 15 can be lowered below the frost limit temperature while maintaining the temperature above the limit temperature.

  For this reason, it is possible to increase the heat absorption amount of the refrigerant in the outdoor heat exchanger 15 as compared with the first dehumidifying and heating mode while preventing the occurrence of frost (frosting) in the evaporator 16, and the air is blown out from the condenser 12. The temperature of the blown air can be increased.

  In the vehicle air conditioner 1 of the present embodiment described above, as described above, by switching the refrigerant flow path of the refrigeration cycle apparatus 10, by appropriately performing cooling, heating, and dehumidifying heating in the vehicle interior, Comfortable air conditioning can be realized.

  In particular, in the vehicle air conditioner 1 of the present embodiment, as the dehumidifying and heating mode, the blown air that is blown into the vehicle interior by adjusting the heat exchange capability (heat dissipation capability and heat absorption capability) in the outdoor heat exchanger 15 is changed from a low temperature range to a high temperature range. It is possible to switch between the first dehumidifying and heating mode in which the temperature can be adjusted over a wide range and the second dehumidifying and heating mode in which the temperature of the blown-out air blown into the vehicle compartment can be adjusted in a high temperature range as compared with the first dehumidifying and heating mode.

  Therefore, the temperature adjustable range of the air blown into the passenger compartment, which is the air conditioning target space, can be expanded.

  According to the present embodiment, the refrigerant absorbs heat in the outdoor heat exchanger 15 and the evaporator 16 in the third and fourth modes of the first dehumidifying and heating mode and the first and second modes of the second dehumidifying and heating mode. As compared with the case where the refrigerant does not absorb heat in the outdoor heat exchanger 15 and radiates heat to the outside air as in the first and second modes of the 1 dehumidifying and heating mode, the temperature of the blown air blown out from the condenser 12 is increased. Can do.

  Moreover, in the first dehumidifying and heating mode, the refrigerant flows in the order of the outdoor heat exchanger 15, the second expansion valve 18, and the evaporator 16, whereas in the second dehumidifying and heating mode, the evaporator is opposite to the first mode. 16, the refrigerant flows in the order of the second expansion valve 18 and the outdoor heat exchanger 15.

  Therefore, in the second dehumidifying and heating mode, the throttle opening of the first expansion valve 13 is adjusted so that the refrigerant evaporation temperature in the evaporator 16 is equal to or higher than the frost limit temperature, and the throttle opening of the second expansion valve 18 is adjusted. Since the heat absorption amount in the outdoor heat exchanger 15 can be increased by reducing the temperature, it is possible to obtain a higher blowing temperature than in the first dehumidifying and heating mode while preventing frost formation in the evaporator 16.

  According to the present embodiment, as described in steps S70 and S100, the first dehumidifying heating mode and the second dehumidifying heating mode are switched based on the temperature difference between the outdoor heat exchanger temperature TO and the evaporator temperature TE. In other words, the first dehumidifying heating mode and the second dehumidifying heating mode are switched based on the pressure difference between the refrigerant pressure in the outdoor heat exchanger 15 and the refrigerant pressure in the evaporator 16. For this reason, the continuity of the blown air temperature can be maintained as much as possible.

The reason will be described below. The heating capacity in the refrigeration cycle is represented by the following formula F2.
Heating capacity of outdoor heat exchanger = heat absorption capacity (dehumidification capacity) of indoor evaporator + compression power + heat exchange amount of outdoor heat exchanger (F2)
Then, when the necessary dehumidifying capacity is maintained, it is necessary to adjust the heat exchange amount of the outdoor heat exchanger in order to control the desired heating capacity.

  FIG. 8 is a graph showing a controllable region of the blowing temperature (that is, the heating capacity) in the first dehumidifying and heating mode and the second dehumidifying and heating mode when the necessary dehumidifying capacity is maintained.

  When the refrigerant evaporation temperature in the evaporator 16 is controlled to the frost limit temperature (for example, 1 ° C.), the fourth heating mode is the highest in the first dehumidifying heating mode and the heating capability is the lowest in the second dehumidifying heating mode. In the first mode, since the refrigerant pressure in the outdoor heat exchanger 15 is the same, the blowing temperature is also the same.

  Accordingly, there is a limit line LL that is the upper limit of the blowing temperature in the first dehumidifying and heating mode and the lower limit temperature of blowing in the second dehumidifying and heating mode.

  On the other hand, in the fourth mode of the first dehumidifying and heating mode, the throttle opening of the second expansion valve 18 is fully opened, so that the refrigerant pressure in the outdoor heat exchanger 15 and the refrigerant pressure in the evaporator 16 are the same, Even in the first mode of the second dehumidifying and heating mode, the throttle opening of the second expansion valve 18 is fully opened, so that the refrigerant pressure in the outdoor heat exchanger 15 and the refrigerant pressure in the evaporator 16 are the same.

  Therefore, when the pressure difference between the refrigerant pressure in the outdoor heat exchanger 15 and the refrigerant pressure in the evaporator 16 is small, the control state close to the limit line LL is achieved by switching between the first dehumidifying heating mode and the second dehumidifying heating mode. Sometimes it is possible to switch between the first dehumidifying and heating mode and the second dehumidifying and heating mode, and thus it is possible to suppress a sudden change in the blown air temperature when switching between the first and second dehumidifying and heating modes.

Furthermore, according to the present embodiment, as described in steps S80 and S110, the first difference is based on the temperature difference between the target blowing temperature TAO and the vehicle cabin blowing air temperature TAV, that is, the excess or deficiency of the heating capacity with respect to the heating load. and dehumidification and heating mode, since than the first dehumidification and heating mode switching between the high second dehumidification and heating modes of heating capacity, to adjust the heating capacity in accordance with the heating load, to achieve a comfortable dehumidifying and heating the passenger compartment be able to.

  In addition, since the first dehumidifying and heating mode and the second dehumidifying and heating mode can be switched with a simple configuration such as the four-way valve 14, it is possible to easily realize a configuration that expands the temperature adjustable range of the blown air into the passenger compartment. Can do.

(Second Embodiment)
In the second embodiment, as shown in FIG. 9, steps S70 and S100 of the first embodiment are changed to steps S71 and S101.

  In step S71, it is determined whether or not the throttle opening degree of the second expansion valve 18 exceeds a predetermined reference value δ1 (hereinafter referred to as a threshold value δ1). As a result, when it is determined that the throttle opening of the second expansion valve 18 is equal to or less than the threshold value δ1 (S71: NO), the temperature adjustable range of the blown air into the vehicle compartment is a wide range from the low temperature range to the high temperature range. When the first dehumidifying and heating mode, which is the normal dehumidifying and heating mode, is determined (S80) and it is determined that the throttle opening of the second expansion valve 18 exceeds the threshold value δ1 (S71: YES), step The process proceeds to S90.

  In step S101, it is determined whether or not the throttle opening of the second expansion valve 18 exceeds a predetermined reference value δ2 (hereinafter referred to as a threshold value δ2). As a result, when it is determined that the throttle opening degree of the second expansion valve 18 is equal to or less than the threshold δ2 (S101: NO), the temperature adjustable range of the blown air into the vehicle compartment is higher than that in the first dehumidifying heating mode. When the second dehumidifying and heating mode is set to the range (S110), and it is determined that the throttle opening of the second expansion valve 18 exceeds the threshold δ2 (S101: YES), the process proceeds to step S120.

  According to the present embodiment, the first dehumidifying heating mode and the second dehumidifying heating mode are switched based on the throttle opening of the second expansion valve 18. In other words, the first dehumidifying heating mode and the second dehumidifying heating mode are switched based on the pressure difference between the refrigerant pressure in the outdoor heat exchanger 15 and the refrigerant pressure in the evaporator 16. For this reason, the continuity of the blown air temperature can be kept as much as possible as in the first embodiment.

(Third embodiment)
In the above embodiment, the condenser 12 heats the vehicle interior blown air by exchanging heat between the discharged refrigerant (high pressure refrigerant) discharged from the compressor 11 and the vehicle interior blown air that has passed through the evaporator 16. Although it is an air heat exchanger, in this 3rd Embodiment, as shown in FIG. 10, the condenser 12 outputs the discharge refrigerant | coolant (high pressure refrigerant | coolant) discharged from the compressor 11, and the driving force for vehicle travel. It is a refrigerant cooling water heat exchanger (refrigerant heat medium heat exchanger) that heats the cooling water by exchanging heat with the cooling water (heat medium) of the engine.

  Furthermore, the cooling water heated by the condenser 12 circulates through the heater core 34 (cooling water heat medium heat exchanger). Thereby, in the heater core 34, the vehicle interior blown air is heated by heat exchange between the cooling water heated by the condenser 12 and the vehicle interior blown air that has passed through the evaporator 16.

  Also in this embodiment, the same operational effects as those in the above embodiment can be obtained.

(Other embodiments)
The above embodiments can be combined as appropriate. The above embodiment can be variously modified as follows, for example.

  (1) In the above embodiment, an example in which the cooling mode, the dehumidifying heating mode (cooling mode), and the heating mode (non-cooling mode) are switched by the operation signal of the A / C switch has been described, but the present invention is not limited to this. For example, an operation mode setting switch for setting each operation mode may be provided on the operation panel, and the heating mode, the cooling mode, and the dehumidifying heating mode may be switched according to an operation signal of the operation mode setting switch.

  (2) In the above embodiment, the control device 50 closes one of the air passage of the indoor condenser 12 and the heater core 34 and the cold air bypass passage 35 in each operation mode of the heating mode, the cooling mode, and the dehumidifying heating mode. The example in which the air mix door 36 is operated as described above has been described, but the operation of the air mix door 36 is not limited to this.

  For example, the air mix door 36 may open both the air passage of the indoor condenser 12 and the heater core 34 and the cold air bypass passage 35. The temperature of the air blown into the vehicle interior may be adjusted by adjusting the air volume ratio between the air volume that passes through the air passages of the indoor condenser 12 and the heater core 34 and the air volume that passes through the cold air bypass passage 35. Good. Such temperature adjustment is effective in that it is easy to finely adjust the temperature of the air blown into the passenger compartment.

  (3) In the first and second embodiments, the heater core 34 is arranged inside the indoor air conditioning unit 30. However, when an external heat source such as an engine is insufficient, the heater core 34 may be eliminated. The heater core 34 may be replaced with an electric heater or the like.

  (4) In the above embodiment, the heater core 34 exchanges heat between the engine coolant and the air blown into the passenger compartment, but the heater core 34 is a coolant for heat-generating equipment such as a traveling electric motor and an inverter. The vehicle interior air may be heat exchanged.

  (5) In each of the above-described embodiments, the example in which the refrigeration cycle apparatus 10 is applied to the vehicle air conditioner 1 has been described. However, the present invention is not limited to this, and for example, the refrigeration cycle apparatus 10 is applied to a stationary air conditioner or the like. May be.

11 Compressor 12 Condenser (radiator)
13 First expansion valve (first decompression means)
14 Second expansion valve (second decompression means)
15 Outdoor heat exchanger 16 Evaporator 14 Four-way valve (switching means)
50 Control device (switching means)

Claims (5)

A compressor (11) for sucking and discharging refrigerant;
Radiators (12, 34) for radiating heat of the refrigerant to the air blown into the air-conditioning target space;
A first depressurizing means (13) and a second depressurizing means (18) configured to change the throttle opening, and depressurizing the refrigerant;
An outdoor heat exchanger (15) for exchanging heat between the refrigerant and outside air;
An evaporator (16) for exchanging heat between the refrigerant and the blown air to evaporate the refrigerant;
The compressor (11), the radiator (12), the first decompression means (13), the outdoor heat exchanger (15), the second decompression means (18), the evaporator (16), the compression A refrigerant circuit in a first dehumidifying and heating mode in which the refrigerant flows in the order of the machine (11);
The compressor (11), the radiator (12), the first decompression means (13), the evaporator (16), the second decompression means (18), the outdoor heat exchanger (15), the compression Switching means (14, 50) for switching the refrigerant circuit in the second dehumidifying and heating mode in which the refrigerant flows in the order of the machine (11),
The first pressure reducing means (13) and the second pressure reducing means (18) are respectively connected to the outdoor heat exchanger (15) and the evaporator (16) in the first dehumidifying heating mode and the second dehumidifying heating mode. Adjust the throttle opening so that the refrigerant absorbs heat ,
The switching means (14, 50)
In the first dehumidifying and heating mode, a temperature difference (TO-TE) obtained by subtracting the refrigerant temperature (TE) in the evaporator (16) from the refrigerant temperature (TO) in the outdoor heat exchanger (15) is a first value. The air temperature (TAV) is decreased from the target air temperature (TAO) below (β1).
When the closed temperature difference (TAO-TAV) exceeds the second value (γ1), switch to the second dehumidifying heating mode,
In the second dehumidifying heating mode, a temperature difference (TE-TO) obtained by subtracting the refrigerant temperature (TO) in the outdoor heat exchanger (15) from the refrigerant temperature (TE) in the evaporator (16) is a third value. The target blowing temperature (TAO) is decreased from (β2) and from the blowing air temperature (TAV).
When the temperature difference (TAV−TAO) that has passed exceeds the fourth value (γ2), the refrigeration cycle apparatus is switched to the first dehumidifying and heating mode . A compressor (11) for sucking and discharging refrigerant;
Radiators (12, 34) for radiating heat of the refrigerant to the air blown into the air-conditioning target space;
A first depressurizing means (13) and a second depressurizing means (18) configured to change the throttle opening, and depressurizing the refrigerant;
An outdoor heat exchanger (15) for exchanging heat between the refrigerant and outside air;
An evaporator (16) for exchanging heat between the refrigerant and the blown air to evaporate the refrigerant;
The compressor (11), the radiator (12), the first decompression means (13), the outdoor heat exchanger (15), the second decompression means (18), the evaporator (16), the compression A refrigerant circuit in a first dehumidifying and heating mode in which the refrigerant flows in the order of the machine (11);
The compressor (11), the radiator (12), the first decompression means (13), the evaporator (16), the second decompression means (18), the outdoor heat exchanger (15), the compression Switching means (14, 50) for switching the refrigerant circuit in the second dehumidifying and heating mode in which the refrigerant flows in the order of the machine (11),
The first pressure reducing means (13) and the second pressure reducing means (18) are respectively connected to the outdoor heat exchanger (15) and the evaporator (16) in the first dehumidifying heating mode and the second dehumidifying heating mode. Adjust the throttle opening so that the refrigerant absorbs heat ,
The switching means (14, 50)
In the first dehumidifying and heating mode, the throttle opening (EVC) of the second decompression means (18) exceeds the first value (δ1) and the blown air temperature (TAV) from the target blown temperature (TAO).
When the reduced temperature difference (TAO-TAV) exceeds the second value (γ1), switch to the second dehumidifying heating mode,
In the second dehumidifying and heating mode, the throttle opening (EVC) of the second decompression means (18) exceeds the third value (δ2), and the target air temperature (TAO) is set from the air temperature (TAV).
When the reduced temperature difference (TAV−TAO) exceeds the fourth value (γ2), the refrigeration cycle apparatus is switched to the first dehumidifying and heating mode . The switching means (14, 50) is based on the pressure difference between the refrigerant pressure in the outdoor heat exchanger (15) and the refrigerant pressure in the evaporator (16), and the excess or deficiency of the heating capacity with respect to the heating load. The refrigeration cycle apparatus according to claim 1 or 2 , wherein the first dehumidifying heating mode and the second dehumidifying heating mode are switched. The heat radiator (12) is a condenser that is disposed in a case (31) through which the blown air flows and that condenses the refrigerant by dissipating heat of the refrigerant to the blown air. Item 4. The refrigeration cycle apparatus according to any one of Items 1 to 3 . The radiator is heat-exchanged between a refrigerant heat medium heat exchanger (12) that exchanges heat between the refrigerant discharged from the compressor (11) and a heat medium, and the refrigerant heat medium heat exchanger (12). The refrigeration cycle apparatus according to any one of claims 1 to 3 , further comprising a heater core (34) for exchanging heat between the heat medium and the blown air.

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