CN117795267A - Refrigeration cycle device - Google Patents

Abstract

Vibration and noise generated by discharge pulsation of a compressor are suppressed. A refrigeration cycle device is provided with: a compressor (11) for sucking, compressing and discharging a refrigerant; a radiator (12) for radiating heat from the refrigerant discharged from the compressor; a decompression unit (14 a) for decompressing the refrigerant radiated by the radiator; and a control unit (60) for controlling the opening degree of the pressure reducing unit to a normal opening degree, wherein the control unit performs liquid discharge control for promoting discharge of the liquid-phase refrigerant stored from the compressor to the pressure reducing unit when the control unit determines that the liquid-phase refrigerant is stored in the compressor at the time of starting the compressor.

Description

Refrigeration cycle device

Cross-reference to related applications

The present application is based on Japanese patent application No. 2021-159346 filed on 9/29 of 2021, and the contents of the description are incorporated herein.

Technical Field

The present invention relates to a refrigeration cycle apparatus including a compressor that sucks, compresses, and discharges a refrigerant.

Background

Conventionally, patent document 1 describes a vehicle air conditioner that performs the following control: the opening degree of the expansion valve is increased at the start of the heating operation as compared with the normal opening degree at the time of the heating operation, the compressor is started, and after a set time has elapsed, the opening degree of the expansion valve is returned to the normal opening degree.

This reduces the flow resistance of the refrigerant in the heating refrigerant circuit at the start of the heating operation, and the refrigerant tends to return to the suction portion of the compressor in advance. Therefore, the internal pressure of the compressor increases in advance, and the operation of the driving portion of the compressor is stabilized, so that the occurrence of vibration and noise of the compressor at the start of the heating operation can be suppressed.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2017-74833

The distribution of the amount of the refrigerant in the refrigeration cycle at the time of the stop naturally changes due to the temperature difference between the components caused by the environmental influence such as the temperature fluctuation in addition to the influence of the operation state before the stop. For example, when the refrigerant is placed in a state where the temperature rises from late night to early morning in winter, the compressor having a larger heat capacity than surrounding components becomes a component having the lowest temperature, and the compressor becomes the lowest pressure, so that the refrigerant moves to the compressor, and a phenomenon occurs in which the liquid refrigerant is stored in the compressor. When the refrigeration cycle is started with the liquid refrigerant stored in the compressor (i.e., when the compressor is started), the liquid refrigerant stored in the compressor is discharged at once, and the high-pressure side refrigerant passage from the compressor to the expansion valve may be filled with the liquid refrigerant. In this state, the discharge pulsation of the compressor does not attenuate and the refrigerant pipe is strongly vibrated, thereby generating abnormal noise.

In particular, in a heat pump cycle in which an indoor heat exchanger having a small refrigerant volume functions as a condenser, a high-pressure side refrigerant passage from a compressor to an expansion valve is easily filled with liquid refrigerant.

As a countermeasure for this, it is considered to reduce the amount of refrigerant to be filled in the cycle or to increase the volume of refrigerant from the compressor to the expansion valve.

However, from the viewpoint of long-time assurance of performance, it is difficult to take countermeasures to reduce the amount of refrigerant to be filled in the cycle. From the standpoint of cost and mountability, it is difficult to take measures to increase the volume of the refrigerant from the compressor to the expansion valve.

Disclosure of Invention

In view of the above, an object of the present invention is to suppress the occurrence of vibration and noise caused by discharge pulsation of a compressor.

A refrigeration cycle apparatus according to a first aspect of the present invention includes a compressor, a radiator, a pressure reducing unit, and a control unit. The compressor sucks, compresses, and discharges a refrigerant. The radiator radiates heat from the refrigerant discharged from the compressor. The pressure reducing unit reduces the pressure of the refrigerant that has been radiated by the radiator. The control unit controls the opening degree of the pressure reducing unit to a normal opening degree.

When it is determined that the liquid-phase refrigerant is stored in the compressor at the time of starting the compressor, the control unit performs liquid discharge control that promotes discharge of the liquid-phase refrigerant stored from the compressor to the decompression unit.

In this way, when the compressor is started, the discharge of the liquid-phase refrigerant stored from the compressor to the pressure reducing portion is promoted, and therefore, the discharge pulsation of the compressor can be suppressed. Therefore, the occurrence of vibration and noise due to discharge pulsation of the compressor can be suppressed.

A refrigeration cycle apparatus according to a second aspect of the present invention includes a compressor, a radiator, a pressure reducing portion, a liquid discharge passage portion, a liquid discharge opening/closing portion, and a control portion. The compressor sucks, compresses, and discharges a refrigerant. The radiator radiates heat from the refrigerant discharged from the compressor. The pressure reducing unit reduces the pressure of the refrigerant that has been radiated by the radiator.

The liquid discharge passage portion forms a refrigerant passage through which the refrigerant flowing out of the radiator flows bypassing the pressure reducing portion. The liquid discharge opening/closing portion opens/closes the liquid discharge passage portion. The control unit performs liquid discharge control for controlling the liquid discharge opening/closing unit to open the liquid discharge passage unit when it is determined that the liquid-phase refrigerant is reserved in the compressor at the time of starting the compressor.

In this way, since the liquid refrigerant passes through the liquid discharge passage portion at the time of starting the compressor, the discharge of the liquid refrigerant stored in the compressor can be promoted. Therefore, since the discharge pulsation of the compressor can be suppressed, the occurrence of vibration and noise due to the discharge pulsation of the compressor can be suppressed.

Drawings

The above objects and other objects, features, and advantages of the present invention will become more apparent by referring to the attached drawings and from the following detailed description.

Fig. 1 is a general configuration diagram showing a refrigeration cycle apparatus according to a first embodiment.

Fig. 2 is a block diagram showing an electric control unit of the refrigeration cycle apparatus according to the first embodiment.

Fig. 3 is a flowchart showing a part of the control process of the control program of the first embodiment.

Fig. 4 is a flowchart showing another part of the control process of the control program of the first embodiment.

Fig. 5 is a flowchart showing the processing of the liquid discharge control of the first embodiment.

Fig. 6 is a diagram illustrating the opening degree of the expansion valve for heating in the liquid discharge control according to the first embodiment.

Fig. 7 is a timing chart showing an example of operation in the liquid discharge control according to the first embodiment.

Fig. 8 is an overall configuration diagram showing a refrigeration cycle apparatus according to the second embodiment.

Detailed Description

Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In each embodiment, the same reference numerals are given to the portions corresponding to the items described in the previous embodiment, and redundant description is omitted. In the case where only a part of the structure is described in each embodiment, other embodiments described above can be applied to other parts of the structure. Not only the combination of the portions that can be combined specifically in each embodiment can be performed, but also the embodiments can be partially combined with each other without being specified as long as the combination is not particularly hindered.

(first embodiment)

The first embodiment will be described with reference to fig. 1 to 7. In the present embodiment, the refrigeration cycle apparatus 10 is applied to a vehicle air conditioner 1, and the vehicle air conditioner 1 is mounted on an electric vehicle that obtains driving force for traveling from an electric motor. The vehicle air conditioner 1 not only performs air conditioning in the vehicle interior as an air-conditioning target space, but also has a function of adjusting the temperature of the battery 80. Therefore, the vehicle air conditioner 1 can also be referred to as an air conditioner having a battery temperature adjustment function.

The battery 80 is a secondary battery that stores electric power supplied to an in-vehicle device such as a motor. The battery 80 of the present embodiment is a lithium ion battery. The battery 80 is a so-called assembled battery in which a plurality of battery cells 81 are stacked and the battery cells 81 are electrically connected in series or parallel.

Such a battery tends to decrease in output at low temperatures and to progress in degradation at high temperatures. Therefore, it is necessary to maintain the temperature of the battery within a suitable temperature range (15 ℃ or higher and 55 ℃ or lower in the present embodiment) in which the charge/discharge capacity of the battery can be fully utilized.

Therefore, in the vehicle air conditioner 1, the battery 80 can be cooled by the cold and hot generated by the refrigeration cycle device 10. Therefore, the cooling target object in the refrigeration cycle apparatus 10 of the present embodiment, which is different from air, is the battery 80.

As shown in the overall configuration diagram of fig. 1, the vehicle air conditioner 1 includes a refrigeration cycle device 10, an indoor air conditioner unit 30, and the like.

The refrigeration cycle device 10 heats air blown into the vehicle interior in order to perform air conditioning in the vehicle interior. Further, the refrigeration cycle device 10 cools the battery 80.

The refrigeration cycle apparatus 10 is configured to be capable of switching a refrigerant circuit for various operation modes to perform air conditioning in a vehicle room. For example, the refrigerant circuit is configured to be switchable between a cooling mode, a dehumidifying and heating mode, a heating mode, and the like. Further, the refrigeration cycle device 10 can switch between an operation mode for cooling the battery 80 and an operation mode for not cooling the battery 80 in each operation mode for air conditioning.

In the refrigeration cycle apparatus 10, an HFO refrigerant (specifically, R1234 yf) is used as the refrigerant. The refrigeration cycle device 10 constitutes a subcritical refrigeration cycle in which the pressure of the discharge refrigerant discharged from the compressor 11 does not exceed the critical pressure of the refrigerant. The refrigerant is mixed with a refrigerating machine oil for lubricating the compressor 11. A part of the refrigerating machine oil circulates in a cycle together with the refrigerant.

The compressor 11 in the constituent devices of the refrigeration cycle apparatus 10 sucks, compresses, and discharges a refrigerant in the refrigeration cycle apparatus 10. The compressor 11 is disposed in a drive device chamber that is disposed in front of the vehicle cabin and accommodates a motor or the like. The compressor 11 is an electric compressor of a fixed capacity type compression mechanism having a fixed discharge capacity driven by an electric motor. The rotation speed (i.e., the refrigerant discharge capacity) of the compressor 11 is controlled by a control signal output from the circulation control device 60 shown in fig. 2.

As shown in fig. 1, the discharge port of the compressor 11 is connected to the inlet side of the indoor condenser 12. The indoor condenser 12 is a heat exchanger for heating that exchanges heat between the high-temperature and high-pressure refrigerant discharged from the compressor 11 and air, condenses the refrigerant, and heats the air. The indoor condenser 12 is disposed in an air conditioning case 31 of the indoor air conditioning unit 30.

The outlet of the indoor condenser 12 is connected to the inlet side of a first three-way joint 13a having three inflow and outflow ports communicating with each other. As such a three-way joint, a structure in which a plurality of pipes are joined and a structure in which a plurality of refrigerant passages are provided in a metal block or a resin block can be adopted.

The refrigeration cycle apparatus 10 includes second to sixth three-way joints 13b to 13f. The basic structure of the second three-way joint 13b to the sixth three-way joint 13f is the same as that of the first three-way joint 13 a.

One outflow port of the first three-way joint 13a is connected to an inlet side of the heating expansion valve 14 a. The other outlet of the first three-way joint 13a is connected to one inlet side of the second three-way joint 13b via a bypass passage 22 a. The opening/closing valve 15a for dehumidification is disposed in the bypass passage 22 a.

The dehumidification on-off valve 15a is a solenoid valve that opens and closes a refrigerant passage connecting the other outflow port side of the first three-way joint 13a and the one inflow port side of the second three-way joint 13 b. The refrigeration cycle apparatus 10 further includes an opening/closing valve 15b for heating. The basic structure of the heating on-off valve 15b is the same as that of the dehumidifying on-off valve 15a.

The opening/closing valve 15a for dehumidification and the opening/closing valve 15b for heating can switch the refrigerant circuit of each operation mode by opening/closing the refrigerant passage. The dehumidification on-off valve 15a and the heating on-off valve 15b are refrigerant circuit switching units for switching the circulating refrigerant circuits. The operation of the dehumidification on-off valve 15a and the heating on-off valve 15b is controlled by a control voltage output from the circulation control device 60.

The heating expansion valve 14a is a heating decompression portion that decompresses the high-pressure refrigerant flowing out from the interior condenser 12 and adjusts the flow rate (mass flow rate) of the refrigerant flowing out to the downstream side at least in the operation mode for heating the vehicle interior. The heating expansion valve 14a is an electrically-operated variable throttle mechanism including a valve element capable of changing the throttle opening and an electric actuator for changing the opening of the valve element.

The refrigeration cycle apparatus 10 includes a refrigeration expansion valve 14b and a cooling expansion valve 14c. The basic configuration of the expansion valve 14b for cooling and the expansion valve 14c for cooling is the same as that of the expansion valve 14a for heating.

The heating expansion valve 14a, the cooling expansion valve 14b, and the cooling expansion valve 14c have a full-open function of fully opening the valve opening so as to hardly exert a flow rate adjusting function and a refrigerant pressure reducing function, thereby functioning as a simple refrigerant passage, and a full-close function of fully closing the valve opening so as to close the refrigerant passage.

The fully open function and the fully closed function allow the heating expansion valve 14a, the cooling expansion valve 14b, and the cooling expansion valve 14c to switch the refrigerant circuits in the respective operation modes.

Therefore, the expansion valve 14a for heating, the expansion valve 14b for cooling, and the expansion valve 14c for cooling of the present embodiment also serve as the refrigerant circuit switching unit. The operations of the heating expansion valve 14a, the cooling expansion valve 14b, and the cooling expansion valve 14c are controlled by control signals (control pulses) output from the circulation control device 60.

An outlet of the heating expansion valve 14a is connected to a refrigerant inlet side of the outdoor heat exchanger 16. The outdoor heat exchanger 16 is a heat exchanger that exchanges heat between the refrigerant flowing out from the heating expansion valve 14a and the outside air blown by a cooling fan, not shown. The outdoor heat exchanger 16 is disposed on the front side in the driving device room. Therefore, when the vehicle is traveling, traveling wind can be blown to the outdoor heat exchanger 16. The refrigerant volume of the outdoor heat exchanger 16 is significantly increased compared to the refrigerant volume of the indoor condenser 12. The outdoor heat exchanger 16 is a high-volume heat exchanger having a larger refrigerant volume than the indoor condenser 12.

The refrigerant outlet of the outdoor heat exchanger 16 is connected to the inlet side of the third three-way joint 13 c. One outlet of the third three-way joint 13c is connected to one inlet side of the fourth three-way joint 13d via a heating passage 22 b. The heating opening/closing valve 15b that opens and closes the refrigerant passage is disposed in the heating passage 22 b.

The other outlet of the third three-way joint 13c is connected to the other inlet side of the second three-way joint 13 b. A check valve 17 is disposed in the refrigerant passage connecting the other outflow port side of the third three-way joint 13c and the other inflow port side of the second three-way joint 13 b. The check valve 17 allows the refrigerant to flow from the third three-way joint 13c side to the second three-way joint 13b side, and prohibits the refrigerant from flowing from the second three-way joint 13b side to the third three-way joint 13c side.

The outflow port of the second three-way joint 13b is connected to the inflow port side of the fifth three-way joint 13 e. One outflow port of the fifth three-way joint 13e is connected to the inlet side of the expansion valve 14b for cooling. The other outflow port of the fifth three-way joint 13e is connected to the inlet side of the expansion valve for cooling 14 c.

The expansion valve 14b is a pressure reducing portion for cooling (in other words, an air conditioning portion) that reduces the pressure of the refrigerant flowing out of the outdoor heat exchanger 16 and adjusts the flow rate of the refrigerant flowing out to the downstream side at least in the operation mode for cooling the vehicle interior.

An outlet of the expansion valve 14b for cooling is connected to a refrigerant inlet side of the indoor evaporator 18. The indoor evaporator 18 is disposed in an air conditioning case 31 of the indoor air conditioning unit 30. The indoor evaporator 18 is a cooling heat exchanger (in other words, an air evaporation unit) that exchanges heat between the low-pressure refrigerant depressurized by the refrigeration expansion valve 14b and the air blown from the blower 32 to evaporate the low-pressure refrigerant, and cools the air by absorbing heat in the low-pressure refrigerant. The refrigerant outlet of the indoor evaporator 18 is connected to one inlet side of the sixth three-way joint 13 f.

The cooling expansion valve 14c is a cooling pressure reducing portion that reduces the pressure of the refrigerant flowing out of the outdoor heat exchanger 16 and adjusts the flow rate of the refrigerant flowing out to the downstream side at least in the operation mode for cooling the battery 80.

The outlet of the cooling expansion valve 14c is connected to the inlet side of the cooling heat exchange unit 52. The cooling heat exchange unit 52 is a so-called direct-cooling type cooler that cools the battery 80 by evaporating the low-pressure refrigerant depressurized by the cooling expansion valve 14c to thereby absorb heat.

In the cooling heat exchange portion 52, a structure having a plurality of refrigerant flow paths connected in parallel to each other is preferably employed so that the entire area of the battery 80 can be cooled uniformly. The outlet of the cooling heat exchange portion 52 is connected to the other inlet side of the sixth three-way joint 13 f.

The outflow port of the sixth three-way joint 13f is connected to the inlet side of the evaporation pressure adjustment valve 20. The vapor pressure adjusting valve 20 maintains the refrigerant vapor pressure in the indoor evaporator 18 at or above a predetermined reference pressure in order to suppress frosting of the indoor evaporator 18. The evaporating pressure adjusting valve 20 is constituted by a mechanical variable throttle mechanism that increases the valve opening degree with an increase in the pressure of the outlet side refrigerant of the indoor evaporator 18.

Thus, the evaporating pressure regulating valve 20 maintains the refrigerant evaporating temperature in the indoor evaporator 18 at or above the frost suppressing temperature (1 ℃ in the present embodiment) at which the frost formation in the indoor evaporator 18 can be suppressed. The evaporation pressure adjustment valve 20 of the present embodiment is disposed downstream of the sixth three-way joint 13f, which is a junction, in the refrigerant flow. Therefore, the evaporation pressure adjustment valve 20 also maintains the refrigerant evaporation temperature in the cooling heat exchange portion 52 at or above the frost formation inhibition temperature.

The outlet of the evaporation pressure control valve 20 is connected to the other inlet side of the fourth three-way joint 13 d. The outflow port of the fourth three-way joint 13d is connected to the inlet side of the reservoir 21. The accumulator 21 is a gas-liquid separator that performs gas-liquid separation of the refrigerant flowing into the inside. The accumulator 21 is also a liquid storage portion that stores the remaining liquid-phase refrigerant in the cycle. The gas-phase refrigerant outlet of the accumulator 21 is connected to the suction port side of the compressor 11.

Next, the indoor air conditioning unit 30 will be described. The indoor air conditioning unit 30 is configured to blow out air temperature-regulated by the refrigeration cycle device 10 into the vehicle interior. The indoor air conditioning unit 30 is disposed inside a forefront instrument panel (instrument panel) in the vehicle interior.

As shown in fig. 1, the indoor air conditioning unit 30 accommodates a blower 32, an indoor evaporator 18, an indoor condenser 12, and the like in an air passage formed in an air conditioning case 31 that forms a casing.

The air conditioning case 31 forms an air passage of air blown into the vehicle interior. The air conditioning case 31 is formed of a resin (e.g., polypropylene) having a certain degree of elasticity and also excellent strength.

An inside-outside air switching device 33 is disposed on the most upstream side of the air flow of the air conditioning case 31. The inside-outside air switching device 33 switches between the introduction of inside air (vehicle interior air) and outside air (vehicle exterior air) into the air-conditioning case 31.

The inside/outside air switching device 33 continuously adjusts the opening areas of the inside air inlet port for introducing the inside air into the air conditioning case 31 and the outside air inlet port for introducing the outside air by the inside/outside air switching door, and changes the ratio of the amount of the inside air to the amount of the outside air. The inside-outside air switching door is driven by an electric actuator for the inside-outside air switching door. The operation of the electric actuator is controlled by a control signal output from the circulation controller 60.

The blower 32 is disposed downstream of the air flow of the inside-outside air switching device 33. The blower 32 blows air sucked through the inside-outside air switching device 33 toward the inside of the vehicle. The blower 32 is an electric blower that drives a centrifugal sirocco fan by a motor. The rotational speed (i.e., blowing capacity) of the blower 32 is controlled by a control voltage output from the circulation control device 60.

On the downstream side of the blower 32 in the air flow, the indoor evaporator 18 and the indoor condenser 12 are arranged in this order with respect to the air flow. That is, the indoor evaporator 18 is disposed upstream of the indoor condenser 12 with respect to the air flow.

A cool air bypass passage 35 is provided in the air conditioning case 31 to allow air passing through the indoor evaporator 18 to bypass the indoor condenser 12. An air mix door 34 is disposed on the downstream side of the air flow of the indoor evaporator 18 and on the upstream side of the air flow of the indoor condenser 12 in the air conditioning case 31.

The air mix door 34 is an air volume ratio adjustment unit that adjusts the air volume ratio between the air volume of the air passing through the indoor condenser 12 and the air volume of the air passing through the cool air bypass passage 35, of the air passing through the indoor evaporator 18. The air mix door 34 is driven by an electric actuator for the air mix door. The operation of the electric actuator is controlled by a control signal output from the circulation controller 60.

A mixing space is disposed on the downstream side of the air flow of the indoor condenser 12 and the cool air bypass passage 35 in the air conditioning case 31. The mixing space is a space in which the air heated by the indoor condenser 12 and the air that has not been heated by the cool air bypass passage 35 are mixed.

An opening hole for blowing out the air (i.e., the conditioned air) mixed in the mixing space into the vehicle interior as the space to be air-conditioned is arranged in the downstream portion of the air flow of the air-conditioning case 31.

As the opening holes of the air conditioning case 31, face opening holes, foot opening holes, and defrost opening holes (all not shown) are provided. The face opening hole is an opening hole for blowing out air-conditioned air toward the upper body of an occupant in the vehicle cabin. The foot opening hole is an opening hole for blowing out air-conditioned air toward the foot side of the occupant. The defroster opening hole is an opening hole for blowing out air-conditioned air toward an inner side surface of a front window glass of the vehicle.

The face opening hole, the foot opening hole, and the defroster opening hole are connected to a face air outlet, a foot air outlet, and a defroster air outlet (not shown) provided in the vehicle interior via pipes forming air passages, respectively.

Accordingly, the air mix door 34 adjusts the temperature of the conditioned air mixed in the mixing space by adjusting the air volume ratio of the air volume passing through the indoor condenser 12 to the air volume passing through the cool air bypass passage 35. The temperature of the air (conditioned air) blown out from each outlet port into the vehicle interior is adjusted.

A face door, a foot door, and a defrost door (not shown) are disposed on the air flow upstream sides of the face opening hole, the foot opening hole, and the defrost opening hole, respectively. The face department adjusts the opening area of the face opening hole. The foot section adjusts the opening area of the foot opening hole. The defrosting door adjusts an opening area of the defrosting opening hole.

The face door, foot door, and defrost door constitute an air outlet mode switching device that switches the air outlet modes. The doors are linked to an electric actuator for driving the air outlet mode door via a link mechanism or the like to perform a rotation operation. The operation of the electric actuator is also controlled by a control signal output from the circulation control device 60.

The air outlet modes switched by the air outlet mode switching device include a face mode, a two-stage mode, a foot mode, and the like.

The face mode is an outlet mode in which the face outlet is fully opened and air is blown out from the face outlet toward the upper body of the occupant in the vehicle compartment. The two-stage mode is an outlet mode in which both the face outlet and the foot outlet are opened to blow out air toward the upper body and the foot side of the occupant in the vehicle compartment. The foot mode is an air outlet mode in which the foot air outlet is fully opened and the defroster air outlet is opened with a small opening, and air is mainly blown out from the foot air outlet.

The occupant may switch to the defrost mode by manually operating a blow-out mode switching switch provided on the operation panel 70. The defrosting mode is an air outlet mode in which the defrosting air outlet is fully opened and air is blown out from the defrosting air outlet to the inner surface of the front window glass.

Next, an outline of the electric control unit according to the present embodiment will be described. The circulation control device 60 is composed of a well-known microcomputer including a CPU, ROM, RAM, and the like, and peripheral circuits. Then, various operations and processes are performed based on a control program stored in the ROM, and operations of various control target devices 11, 14a to 14c, 15a, 15b, 32 and the like connected to the output side are controlled.

As shown in the block diagram of fig. 2, an inside air temperature sensor 61, an outside air temperature sensor 62, a solar sensor 63, first to fifth refrigerant temperature sensors 64a to 64e, an evaporator temperature sensor 64f, a cooling heat exchange unit inlet temperature sensor 64g, a first refrigerant pressure sensor 65a, a second refrigerant pressure sensor 65b, an air conditioner temperature sensor 68, a battery control device 69, and the like are connected to the input side of the circulation control device 60. The detection signals of these sensor groups are input to the circulation control device 60.

The inside air temperature sensor 61 is an inside air temperature detecting unit that detects an inside air temperature (inside air temperature) Tr of the vehicle interior. The outside air temperature sensor 62 is an outside air temperature detecting unit that detects an outside air temperature Tam (outside air temperature). The sunlight sensor 63 is a sunlight amount detection unit that detects the sunlight amount Ts emitted into the vehicle interior.

The first refrigerant temperature sensor 64a is a discharged refrigerant temperature detecting unit that detects the temperature T1 of the refrigerant discharged from the compressor 11. The second refrigerant temperature sensor 64b is a second refrigerant temperature detecting unit that detects the temperature T2 of the refrigerant flowing out of the indoor condenser 12. The third refrigerant temperature sensor 64c is a third refrigerant temperature detecting unit that detects the temperature T3 of the refrigerant flowing out of the outdoor heat exchanger 16.

The fourth refrigerant temperature sensor 64d is a fourth refrigerant temperature detecting unit that detects the temperature T4 of the refrigerant flowing out of the indoor evaporator 18. The fifth refrigerant temperature sensor 64e is a fifth refrigerant temperature detecting unit that detects the temperature T5 of the refrigerant flowing out of the cooling heat exchanging unit 52.

The evaporator temperature sensor 64f is an evaporator temperature detecting portion that detects the refrigerant evaporation temperature (evaporator temperature) Tefin in the indoor evaporator 18. In the evaporator temperature sensor 64f of the present embodiment, the heat exchange fin temperature of the indoor evaporator 18 is specifically detected.

The cooling heat exchange unit inlet temperature sensor 64g is a cooling heat exchange unit inlet temperature detection unit that detects the temperature of the refrigerant flowing into the refrigerant passage of the cooling heat exchange unit 52.

The first refrigerant pressure sensor 65a is a first refrigerant pressure detecting portion that detects the pressure P1 of the refrigerant flowing out of the indoor condenser 12. The second refrigerant pressure sensor 65b is a second refrigerant pressure detecting portion that detects the pressure P2 of the refrigerant flowing out of the refrigerant passage of the cooling heat exchanging portion 52.

The air-conditioning temperature sensor 68 is an air-conditioning temperature detecting unit that detects the air temperature TAV heated by the indoor condenser 12.

The battery control device 69 is a battery control unit that controls input and output of the battery 80. The detection signal from the battery temperature sensor 69a is input to the battery control device 69.

The battery temperature sensor 69a is a battery temperature detection unit that detects the battery temperature TB (i.e., the temperature of the battery 80). The battery temperature sensor 69a of the present embodiment has a plurality of temperature sensors, and detects temperatures of a plurality of portions of the battery 80. Therefore, the circulation control device 60 can also detect the temperature difference between the respective portions of the battery 80. As the battery temperature TB, an average value of the detection values of a plurality of temperature sensors is used.

Information such as the time at which the quick charge of the battery 80 is started, the battery temperature TB, and the like is input from the battery control device 69 to the circulation control device 60.

As shown in fig. 2, the input side of the circulation control device 60 is connected to an operation panel 70 disposed near an instrument panel at the front of the vehicle interior, and receives operation signals from various operation switches provided on the operation panel 70.

Specifically, the various operation switches provided on the operation panel 70 include an automatic switch for setting or canceling an automatic control operation of the vehicle air conditioner, an air conditioner switch for requesting air cooling by the indoor evaporator 18, an air volume setting switch for manually setting an air volume of the blower 32, a temperature setting switch for setting a target temperature Tset in the vehicle interior, and a blowout mode switching switch for manually setting a blowout mode.

In the circulation control device 60 of the present embodiment, the control unit that controls various control target devices connected to the output side is integrally configured, but the configuration (hardware and software) that controls the operation of each control target device constitutes the control unit that controls the operation of each control target device.

For example, the configuration of the circulation control device 60 that controls the refrigerant discharge capacity of the compressor 11 (specifically, the rotation speed of the compressor 11) constitutes the compressor control portion 60a. The expansion valve controller 60b is configured to control the operation of the heating expansion valve 14a, the cooling expansion valve 14b, and the cooling expansion valve 14 c. The refrigerant circuit switching control unit 60c is configured to control the operation of the dehumidification on-off valve 15a and the heating on-off valve 15 b.

Next, the operation of the present embodiment configured as described above will be described. As described above, the vehicle air conditioner 1 according to the present embodiment has a function of adjusting the temperature of the battery 80 in addition to the air conditioning in the vehicle cabin. Therefore, in the refrigeration cycle apparatus 10, the refrigerant circuit is switched, and the following operation in eleven operation modes can be performed.

(1) Cooling mode: the cooling mode is an operation mode in which cooling of the battery 80 is not performed, but air is cooled and blown into the vehicle interior to cool the vehicle interior.

(2) Serial dehumidification and heating mode: the serial dehumidification and heating mode is an operation mode in which the battery 80 is not cooled, and the cooled and dehumidified air is reheated and blown into the vehicle interior to dehumidify and heat the vehicle interior.

(3) Parallel dehumidification heating mode: the parallel dehumidification and heating mode is an operation mode in which the battery 80 is not cooled, but the cooled and dehumidified air is reheated with a higher heating capacity than the serial dehumidification and heating mode and blown out into the vehicle interior to perform dehumidification and heating in the vehicle interior.

(4) Heating mode: the heating mode is an operation mode in which the battery 80 is not cooled, but air is heated and blown into the vehicle interior to heat the vehicle interior.

(5) Cooling mode: the cooling mode is an operation mode in which the battery 80 is cooled, and the air is cooled and blown into the vehicle interior to cool the vehicle interior.

(6) Serial dehumidification heating and cooling mode: the series dehumidification heating cooling mode is an operation mode in which the battery 80 is cooled, and the cooled and dehumidified air is reheated and blown into the vehicle interior to dehumidify and heat the vehicle interior.

(7) Parallel dehumidification heating cooling mode: the parallel dehumidification heating cooling mode is an operation mode in which the battery 80 is cooled, and the dehumidified air is reheated with a higher heating capacity than in the series dehumidification heating cooling mode and blown out into the vehicle interior to perform dehumidification heating in the vehicle interior.

(8) Heating and cooling mode: the heating/cooling mode is an operation mode in which the battery 80 is cooled, and the air is heated and blown into the vehicle interior to heat the vehicle interior.

(9) Heating serial cooling mode: the heating-series cooling mode is an operation mode in which the battery 80 is cooled, and air is heated with a higher heating capacity than the heating-series cooling mode and blown into the vehicle interior to heat the vehicle interior.

(10) Heating parallel cooling mode: the parallel heating and cooling mode is an operation mode in which the battery 80 is cooled, and air is heated with a higher heating capacity than the serial heating and cooling mode and blown into the vehicle interior to heat the vehicle interior.

(11) Cooling mode: the cooling mode is an operation mode in which the battery 80 is cooled without air conditioning in the vehicle cabin.

The switching of these operation modes is performed by executing a control program. The control routine is executed when the automatic control in the vehicle interior is set by turning ON (ON) the automatic switch of the operation panel 70 by the operation of the occupant. The control program will be described with reference to fig. 3 to 5. The control steps shown in the flowcharts of fig. 3 and the like are function implementation units included in the circulation control device 60.

First, in step S10 of fig. 3, the detection signal of the sensor group and the operation signal of the operation panel 70 are read. Next, in step S20, a target blowout temperature TAO, which is a target temperature of air blown into the vehicle interior, is determined based on the detection signal and the operation signal read in step S10. Therefore, step S20 is a target blowout temperature determination unit.

Specifically, the target blowout temperature TAO is calculated using the following equation F1.

TAO＝Kset×Tset-Kr×Tr-Kam×Tam-Ks×Ts+C…(F1)

Further, tset is the set temperature in the vehicle interior set by the temperature setting switch. Tr is the vehicle interior temperature detected by the internal air sensor. Tam is the vehicle exterior temperature detected by the outside air sensor. Ts is the amount of sunlight detected by the sunlight sensor. Kset, kr, kam, ks is a control gain, and C is a constant for correction.

Next, in step S30, it is determined whether or not the air conditioner switch is turned ON (ON). The air-conditioning switch being on means that the occupant requires cooling or dehumidification of the vehicle interior. In other words, the air conditioning switch being on means that air is required to be cooled by the indoor evaporator 18.

When it is determined in step S30 that the air conditioner switch is on, the flow proceeds to step S40. If it is determined in step S30 that the air conditioner switch is not on, the routine proceeds to step S160.

In step S40, it is determined whether or not the outside air temperature Tam is equal to or higher than a predetermined reference outside air temperature KA (0 ℃ in the present embodiment). The reference outside air temperature KA is set so that cooling air by the indoor evaporator 18 is effective for cooling or dehumidifying the space to be air-conditioned.

More specifically, in the present embodiment, in order to suppress the frosting of the indoor evaporator 18, the refrigerant evaporation temperature in the indoor evaporator 18 is maintained at the frosting suppression temperature (1 ℃ in the present embodiment) or higher by the evaporation pressure regulating valve 20. Therefore, in the indoor evaporator 18, the air cannot be cooled to a temperature lower than the frost suppressing temperature.

That is, when the temperature of the air flowing into the indoor evaporator 18 is lower than the frost suppressing temperature, it is not effective to cool the air by the indoor evaporator 18. Therefore, the reference outside air temperature KA is set to a value lower than the frost formation inhibition temperature, and when the outside air temperature Tam is lower than the reference outside air temperature KA, the air is not cooled by the indoor evaporator 18.

When it is determined in step S40 that the outside air temperature Tam is equal to or higher than the reference outside air temperature KA, the routine proceeds to step S50. If it is determined in step S40 that the outside air temperature Tam is not equal to or higher than the reference outside air temperature KA, the routine proceeds to step S160.

In step S50, it is determined whether or not the target blowing temperature TAO is equal to or lower than the cooling reference temperature α1. The reference temperature α1 for cooling is determined by the circulation control device 60.

In step S50, when it is determined that the target outlet temperature TAO is equal to or lower than the cooling reference temperature α1, the flow proceeds to step S60. If it is determined in step S50 that the target outlet temperature TAO is not equal to or lower than the cooling reference temperature α1, the routine proceeds to step S90.

In step S60, it is determined whether or not the battery 80 needs cooling. Specifically, in the present embodiment, when the battery temperature TB detected by the battery temperature sensor 69a is equal to or higher than the predetermined reference cooling temperature KTB (35 ℃ in the present embodiment), it is determined that the battery 80 needs to be cooled. When battery temperature TB is lower than reference cooling temperature KTB, it is determined that cooling of battery 80 is not necessary.

If it is determined in step S60 that the battery 80 needs to be cooled, the routine proceeds to step S70, and the (5) cooling/cooling mode is selected as the operation mode. If it is determined in step S60 that the battery 80 does not need to be cooled, the routine proceeds to step S80, and the cooling mode (1) is selected as the operation mode.

In step S90, it is determined whether or not the target outlet air temperature TAO is equal to or lower than the reference temperature β1 for dehumidification. The reference temperature β1 for dehumidification is determined by the circulation control device 60. The reference temperature β1 for dehumidification is determined to be a value higher than the reference temperature α1 for refrigeration.

In step S90, when it is determined that the target outlet temperature TAO is equal to or lower than the reference temperature β1 for dehumidification, the flow proceeds to step S100. In step S90, when it is determined that the target outlet temperature TAO is not equal to or lower than the reference temperature β1 for dehumidification, the flow proceeds to step S130.

In step S100, it is determined whether or not cooling of the battery 80 is necessary, as in step S60.

If it is determined in step S100 that the battery 80 needs to be cooled, the routine proceeds to step S110, and the series dehumidification heating cooling mode (6) is selected as the operation mode of the refrigeration cycle apparatus 10. If it is determined in step S100 that cooling of the battery 80 is not necessary, the routine proceeds to step S120, and (2) the series dehumidification and heating mode is selected as the operation mode.

In step S130, it is determined whether or not cooling of the battery 80 is necessary, as in step S60.

If it is determined in step S130 that the battery 80 needs to be cooled, the routine proceeds to step S140, and the parallel dehumidification heating cooling mode is selected (7) as the operation mode of the refrigeration cycle apparatus 10. If it is determined in step S100 that cooling of the battery 80 is not necessary, the routine proceeds to step S150, and (3) the parallel dehumidification and heating mode is selected as the operation mode.

Next, the case of going from step S30 or step S40 to step S160 will be described. The case of proceeding from step S30 or step S40 to step S160 is a case where it is determined that it is not effective to cool the air by the indoor evaporator 18. In step S160, as shown in fig. 4, it is determined whether or not the target blowing temperature TAO is equal to or higher than the heating reference temperature γ.

The heating reference temperature γ is determined by the circulation control device 60. The heating reference temperature γ is set so that heating the air by the indoor condenser 12 is effective for heating the air-conditioning target space.

In step S160, it is determined that the target outlet temperature TAO is equal to or higher than the heating reference temperature γ, and the air needs to be heated by the indoor condenser 12, and the flow proceeds to step S170. In step S160, it is determined that the target outlet temperature TAO is not equal to or higher than the heating reference temperature γ, and that the air does not need to be heated by the indoor condenser 12, the flow proceeds to step S240.

In step S170, it is determined whether or not cooling of the battery 80 is necessary, as in step S60.

If it is determined in step S170 that the battery 80 needs to be cooled, the routine proceeds to step S180. If it is determined in step S170 that cooling of the battery 80 is not necessary, the routine proceeds to step S230, and the heating mode (4) is selected as the operation mode.

Here, when it is determined in step S170 that the battery 80 needs to be cooled and the process advances to step S180, both the heating in the vehicle cabin and the cooling of the battery 80 need to be performed. Therefore, in the refrigeration cycle apparatus 10, it is necessary to appropriately adjust the amount of heat released from the refrigerant into the air in the indoor condenser 12 and the amount of heat absorbed from the battery 80 by the refrigerant in the cooling heat exchange portion 52.

Therefore, in the refrigeration cycle device 10 of the present embodiment, when both the heating in the vehicle interior and the cooling of the battery 80 are required, as shown in steps S180 to S220 of fig. 4, three operation modes of (8) the heating/cooling mode, (9) the heating/serial cooling mode, and (10) the heating/parallel cooling mode are switched.

First, in step S180, it is determined whether or not the target blowout temperature TAO is equal to or lower than the low temperature side cooling reference temperature α2. The low-temperature-side cooling reference temperature α2 is determined by the circulation control device 60. The low-temperature-side cooling reference temperature α2 is determined to be a value higher than the cooling reference temperature α1 and lower than the dehumidification reference temperature β1.

If it is determined in step S180 that the target outlet temperature TAO is equal to or lower than the low-temperature side cooling reference temperature α2, the routine proceeds to step S190, and the heating/cooling mode (8) is selected as the operation mode. In step S180, when it is determined that the target outlet temperature TAO is not equal to or lower than the low-temperature side cooling reference temperature α2, the flow proceeds to step S200.

In step S200, it is determined whether or not the target blowout temperature TAO is equal to or lower than the high temperature side cooling reference temperature β2. The high-temperature-side cooling reference temperature β2 is determined by the circulation control device 60. The high-temperature-side cooling reference temperature β2 is determined to be a value higher than the reference temperature β1 for dehumidification.

If it is determined in step S200 that the target outlet temperature TAO is equal to or lower than the high-temperature side cooling reference temperature β2, the routine proceeds to step S210, and the heating-series cooling mode is selected (9) as the operation mode. If it is determined in step S200 that the target outlet temperature TAO is not equal to or lower than the high-temperature side cooling reference temperature β2, the routine proceeds to step S220, and the heating parallel cooling mode is selected (10) as the operation mode.

Next, the case of proceeding from step S160 to step S240 will be described. The step S160 is performed in step S240 without heating the air by the indoor condenser 12. Therefore, in step S240, it is determined whether or not cooling of the battery 80 is necessary, as in step S60.

If it is determined in step S240 that cooling of the battery 80 is necessary, the routine proceeds to step S250, and the cooling mode is selected (11) as the operation mode. If it is determined in step S200 that cooling of the battery 80 is not necessary, the routine proceeds to step S260, and the blower mode is selected as the operation mode, and the routine returns to step S10.

The air blowing mode is an operation mode in which the compressor 11 is stopped and the blower 32 is operated in accordance with a setting signal set by the air volume setting switch. In step S240, it is determined that the cooling of the battery 80 is not necessary, and the refrigeration cycle device 10 for air conditioning in the vehicle interior and cooling of the battery is not required to operate.

In the control routine of the present embodiment, as described above, the operation mode of the refrigeration cycle apparatus 10 is switched.

The following describes the detailed operation of the vehicle air conditioner 1 in each operation mode. In each operation mode, the circulation control device 60 executes a control flow for each operation mode.

(1) Refrigeration mode

In the control flow of the cooling mode, the target evaporator temperature TEO is determined in the initial step. The target evaporator temperature TEO is determined based on the target blowout temperature TAO with reference to a control map stored in the circulation control device 60. In the control map of the present embodiment, the target evaporator temperature TEO is determined to rise as the target blowout temperature TAO rises.

In the next step, the increase/decrease amount Δivo of the rotation speed of the compressor 11 is determined. Based on the deviation between the target evaporator temperature TEO and the evaporator temperature Tefin detected by the evaporator temperature sensor 64f, the increase amount Δivo is determined by a feedback control method so that the evaporator temperature Tefin approaches the target evaporator temperature TEO.

In the next step, the target supercooling degree SCO1 of the refrigerant flowing out of the outdoor heat exchanger 16 is determined. The target supercooling degree SCO1 is determined based on the outside air temperature Tam and referring to a control map, for example. In the control map of the present embodiment, the target supercooling degree SCO1 is determined so that the coefficient of performance (COP) of the cycle is close to the maximum value.

In the next step, the increase/decrease amount Δevc of the throttle opening degree of the expansion valve 14b for cooling is determined. Based on the deviation between the target supercooling degree SCO1 and the supercooling degree SC1 of the outlet side refrigerant of the outdoor heat exchanger 16, the increase/decrease amount Δevc is determined by the feedback control method so that the supercooling degree SC1 of the outlet side refrigerant of the outdoor heat exchanger 16 approaches the target supercooling degree SCO1.

The degree of supercooling SC1 of the outlet side refrigerant of the outdoor heat exchanger 16 is calculated based on the temperature T3 detected by the third refrigerant temperature sensor 64c and the pressure P1 detected by the first refrigerant pressure sensor 65 a.

In the next step, the opening SW of the air mix door 34 is calculated using the following equation F2.

SW＝{TAO+(Tefin+C2)}/{TAV+(Tefin+C2)}…(F2)

The TAV is an air temperature detected by the air conditioning temperature sensor 68. C2 is a constant for control.

In the next step, in order to switch the refrigeration cycle apparatus 10 to the refrigerant circuit in the cooling mode, the heating expansion valve 14a is set to the fully opened state, the cooling expansion valve 14b is set to the throttled state that exerts the refrigerant decompression action, the cooling expansion valve 14c is set to the fully closed state, the dehumidification on-off valve 15a is closed, and the heating on-off valve 15b is closed. Further, a control signal or a control voltage is outputted to each control target device to obtain the control state determined in the above step, and the control state is returned to the first step.

Therefore, in the refrigeration cycle apparatus 10 in the cooling mode, a vapor compression refrigeration cycle is configured in which the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the heating expansion valve 14a, the outdoor heat exchanger 16, the check valve 17, the cooling expansion valve 14b, the indoor evaporator 18, the evaporation pressure control valve 20, the accumulator 21, and the compressor 11.

That is, in the refrigeration cycle apparatus 10 in the cooling mode, the indoor condenser 12 and the outdoor heat exchanger 16 function as a radiator (in other words, a radiating portion) that radiates heat from the refrigerant discharged from the compressor 11, the expansion valve 14b for cooling functions as a decompression portion that decompresses the refrigerant, and the indoor evaporator 18 functions as a vapor compression refrigeration cycle.

Thereby, the air can be cooled by the indoor evaporator 18, and the air can be heated by the indoor condenser 12.

Accordingly, in the air conditioner 1 for a vehicle in the cooling mode, the opening degree of the air mix door 34 is adjusted, and a part of the air cooled by the indoor evaporator 18 is reheated by the indoor condenser 12, so that the air temperature-adjusted to approach the target outlet temperature TAO is blown into the vehicle interior, whereby cooling in the vehicle interior can be performed.

(2) Series dehumidification heating mode

In the control flow of the series dehumidification and heating mode, the target evaporator temperature TEO is determined in the initial step as in the cooling mode. In the next step, the increase/decrease amount Δivo of the rotation speed of the compressor 11 is determined in the same manner as in the cooling mode.

In the next step, a target temperature TAVO of the air heated by the indoor condenser 12 (hereinafter referred to as a target air heating temperature) is determined so that the air can be heated by the indoor condenser 12. The target air heating temperature TAVO is determined with reference to the control map based on the target outlet temperature TAO and the efficiency of the indoor condenser 12. In the control map of the present embodiment, the target air heating temperature TAVO is determined to be increased as the target blowing temperature TAO increases.

In the next step, the amount of change Δkpn1 of the opening pattern KPN1 is determined. The opening degree pattern KPN1 is a parameter for determining a combination of the throttle opening degree of the expansion valve for heating 14a and the throttle opening degree of the expansion valve for cooling 14 b.

Specifically, in the series dehumidification and heating mode, as the target blowout temperature TAO increases, the opening mode KPN1 increases. Then, as the opening mode KPN1 increases, the throttle opening of the heating expansion valve 14a decreases, and the throttle opening of the cooling expansion valve 14b increases.

In the next step, the opening SW of the air mix door 34 is calculated in the same manner as in the cooling mode. Here, in the series dehumidification and heating mode, the target blowing temperature TAO is higher than in the cooling mode, and therefore the opening degree SW of the air mix door 34 is close to 100%. Therefore, in the series dehumidification and heating mode, the opening degree of the air mix door 34 is determined so that substantially the entire flow rate of the air passing through the indoor evaporator 18 passes through the indoor condenser 12.

In the next step, in order to switch the refrigeration cycle apparatus 10 to the refrigerant circuit of the serial dehumidification heating mode, the heating expansion valve 14a is set to the throttled state, the cooling expansion valve 14b is set to the throttled state, the cooling expansion valve 14c is set to the fully closed state, the dehumidification on-off valve 15a is closed, and the heating on-off valve 15b is closed. Further, a control signal or a control voltage is outputted to each control target device to obtain the control state determined in the above step, and the control state is returned to the first step.

Therefore, in the serial dehumidification and heating mode refrigeration cycle apparatus 10, a vapor compression refrigeration cycle is configured in which the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the heating expansion valve 14a, the outdoor heat exchanger 16, the check valve 17, the cooling expansion valve 14b, the indoor evaporator 18, the evaporation pressure control valve 20, the accumulator 21, and the compressor 11.

That is, in the refrigeration cycle apparatus 10 of the tandem dehumidification and heating mode, the indoor condenser 12 functions as a radiator (in other words, a radiating portion) that radiates heat from the refrigerant discharged from the compressor 11, the heating expansion valve 14a and the cooling expansion valve 14b function as pressure reducing portions, and the indoor evaporator 18 functions as a vapor compression refrigeration cycle of the evaporator.

Further, a cycle is configured in which the outdoor heat exchanger 16 functions as a radiator (in other words, a heat radiating portion) when the saturation temperature of the refrigerant in the outdoor heat exchanger 16 is higher than the outside air temperature Tam. A cycle is configured in which the outdoor heat exchanger 16 functions as an evaporator when the saturation temperature of the refrigerant in the outdoor heat exchanger 16 is lower than the outside air temperature Tam.

Thereby, the air can be cooled by the indoor evaporator 18, and the air can be heated by the indoor condenser 12. Therefore, in the vehicle air conditioner 1 of the tandem dehumidification and heating mode, the air cooled and dehumidified by the indoor evaporator 18 is reheated by the indoor condenser 12 and blown into the vehicle interior, whereby dehumidification and heating of the vehicle interior can be performed.

(3) Parallel dehumidification heating mode

In the first step of the control flow of the parallel dehumidification and heating mode, the target air heating temperature TAVO is determined so that the air can be heated by the indoor condenser 12, similarly to the series dehumidification and heating mode.

In the next step, the increase/decrease amount Δivo of the rotation speed of the compressor 11 is determined. In the parallel dehumidification and heating mode, the increase amount Δivo is determined by a feedback control method based on the deviation between the target air heating temperature TAVO and the air temperature TAV so that the air temperature TAV approaches the target air heating temperature TAVO.

In the next step, a target superheat degree shao of the outlet side refrigerant of the indoor evaporator 18 is determined. As the target superheat degree shim, a predetermined constant (5 ℃ in the present embodiment) can be used.

In the next step, the amount of change Δkpn1 of the opening pattern KPN1 is determined. In the parallel dehumidification and heating mode, the degree of superheat SHE is determined by a feedback control method based on a deviation between the target degree of superheat SHE and the degree of superheat SHE of the refrigerant on the outlet side of the indoor evaporator 18, and is close to the target degree of superheat SHE.

The superheat SHE of the outlet-side refrigerant of the indoor evaporator 18 is calculated based on the temperature T4 detected by the fourth refrigerant temperature sensor 64d and the evaporator temperature Tefin.

In the parallel dehumidification and heating mode, as the opening mode KPN1 increases, the throttle opening of the heating expansion valve 14a decreases, and the throttle opening of the cooling expansion valve 14b increases. Therefore, when the opening mode KPN1 increases, the flow rate of the refrigerant flowing into the indoor evaporator 18 increases, and the degree of superheat SHE of the outlet side refrigerant of the indoor evaporator 18 decreases.

In the next step, the opening SW of the air mix door 34 is calculated in the same manner as in the cooling mode. Here, in the parallel dehumidification and heating mode, since the target discharge temperature TAO is higher than in the cooling mode, the opening degree SW of the air mix door 34 is close to 100% similarly to the serial dehumidification and heating mode. Accordingly, in the parallel dehumidification and heating mode, the opening degree of the air mix door 34 is determined so that substantially the entire flow rate of the air passing through the indoor evaporator 18 passes through the indoor condenser 12.

In the next step, in order to switch the refrigeration cycle apparatus 10 to the parallel dehumidification heating mode refrigerant circuit, the heating expansion valve 14a is set to the throttled state, the cooling expansion valve 14b is set to the throttled state, the cooling expansion valve 14c is set to the fully closed state, the dehumidification on-off valve 15a is opened, and the heating on-off valve 15b is opened. Further, a control signal or a control voltage is outputted to each control target device to obtain the control state determined in the above step, and the process returns to the initial step.

Therefore, in the refrigeration cycle apparatus 10 of the parallel dehumidification and heating mode, a refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the heating expansion valve 14a, the outdoor heat exchanger 16, the heating passage 22b, the accumulator 21, and the compressor 11, and the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the bypass passage 22a, the refrigeration expansion valve 14b, the indoor evaporator 18, the evaporation pressure control valve 20, the accumulator 21, and the compressor 11.

That is, in the refrigeration cycle apparatus 10 of the parallel dehumidification and heating mode, a refrigeration cycle is configured in which the indoor condenser 12 functions as a radiator (in other words, a radiating portion) that radiates heat from the refrigerant discharged from the compressor 11, the heating expansion valve 14a functions as a pressure reducing portion, the outdoor heat exchanger 16 functions as an evaporator, the refrigeration expansion valve 14b connected in parallel to the heating expansion valve 14a and the outdoor heat exchanger 16 functions as a pressure reducing portion, and the indoor evaporator 18 functions as an evaporator.

Thereby, the air can be cooled by the indoor evaporator 18, and the air can be heated by the indoor condenser 12. Therefore, in the vehicle air conditioner 1 of the parallel dehumidification and heating mode, the air cooled and dehumidified by the indoor evaporator 18 is reheated by the indoor condenser 12 and blown into the vehicle interior, and dehumidification and heating of the vehicle interior can be performed.

(4) Heating mode

In the first step of the control flow of the heating mode, the target air heating temperature TAVO is determined in the same manner as in the parallel dehumidification heating mode. In the next step, the increase/decrease amount Δivo of the rotation speed of the compressor 11 is determined in the same manner as in the parallel dehumidification and heating mode.

In the next step, a target supercooling degree SCO2 of the refrigerant flowing out of the indoor condenser 12 is determined. The target supercooling degree SCO2 is determined by referring to the control map based on the intake temperature of the air flowing into the indoor evaporator 18 or the outside air temperature Tam. In the control map of the present embodiment, the target supercooling degree SCO2 is determined so that the coefficient of performance (COP) of the cycle approaches the maximum value.

In the next step, the increase/decrease amount Δevh of the throttle opening degree of the expansion valve 14a for heating is determined. Based on the deviation between the target supercooling degree SCO2 and the supercooling degree SC2 of the refrigerant flowing out of the indoor condenser 12, the increase/decrease amount Δevh is determined by a feedback control method so that the supercooling degree SC2 of the refrigerant flowing out of the indoor condenser 12 approaches the target supercooling degree SCO2.

The degree of supercooling SC2 of the refrigerant flowing out of the indoor condenser 12 is calculated based on the temperature T2 detected by the second refrigerant temperature sensor 64b and the pressure P1 detected by the first refrigerant pressure sensor 65 a.

In the next step, the opening SW of the air mix door 34 is calculated in the same manner as in the cooling mode. Here, in the heating mode, the target blowing temperature TAO is higher than in the cooling mode, and therefore the opening degree SW of the air mix door 34 is close to 100%. Accordingly, in the heating mode, the opening degree of the air mix door 34 is determined so that substantially the entire flow rate of the air passing through the indoor evaporator 18 passes through the indoor condenser 12.

In the next step, in order to switch the refrigeration cycle apparatus 10 to the heating mode refrigerant circuit, the heating expansion valve 14a is set to the throttled state, the cooling expansion valve 14b is set to the fully closed state, the cooling expansion valve 14c is set to the fully closed state, the dehumidification on-off valve 15a is closed, and the heating on-off valve 15b is opened. Further, a control signal or a control voltage is outputted to each control target device to obtain the control state determined in the above step, and the process returns to the initial step.

Therefore, in the refrigeration cycle apparatus 10 of the heating mode, a vapor compression refrigeration cycle is configured in which the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the heating expansion valve 14a, the outdoor heat exchanger 16, the heating passage 22b, the accumulator 21, and the compressor 11.

That is, in the refrigeration cycle apparatus 10 of the heating mode, a refrigeration cycle is configured in which the indoor condenser 12 functions as a radiator (in other words, a radiating portion) that radiates heat from the refrigerant discharged from the compressor 11, the heating expansion valve 14a functions as a decompression portion, and the outdoor heat exchanger 16 functions as an evaporator.

Thereby, the air can be heated by the indoor condenser 12. Therefore, in the air conditioner 1 for a vehicle in the heating mode, the air heated by the indoor condenser 12 is blown into the vehicle interior, so that the heating in the vehicle interior can be performed.

(5) Refrigeration cooling mode

In the cooling mode, the cooling expansion valve 14c is in a throttle state that exhibits a refrigerant decompression function, as opposed to the cooling mode described above.

Therefore, in the refrigeration cycle apparatus 10 in the cooling/cooling mode, the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the heating expansion valve 14a, the outdoor heat exchanger 16, the check valve 17, the cooling expansion valve 14b, the indoor evaporator 18, the evaporation pressure adjusting valve 20, the accumulator 21, and the compressor 11, and the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the heating expansion valve 14a, the outdoor heat exchanger 16, the check valve 17, the cooling expansion valve 14c, the cooling heat exchange portion 52, the evaporation pressure adjusting valve 20, the accumulator 21, and the compressor 11.

That is, in the refrigeration cycle apparatus 10 in the cooling mode, the indoor condenser 12 and the outdoor heat exchanger 16 function as a radiator (in other words, a radiating portion) that radiates heat from the refrigerant discharged from the compressor 11, the refrigeration expansion valve 14b functions as a pressure reducing portion, the indoor evaporator 18 functions as an evaporator, the cooling expansion valve 14c connected in parallel to the refrigeration expansion valve 14b and the indoor evaporator 18 functions as a pressure reducing portion, and the cooling heat exchanging portion 52 functions as an evaporator.

Thereby, the air can be cooled by the indoor evaporator 18, and the air can be heated by the indoor condenser 12. Further, the low-pressure side heat medium can be cooled by the cooling heat exchange unit 52.

Accordingly, in the air conditioning apparatus 1 for a vehicle in the cooling mode, the opening degree of the air mix door 34 is adjusted, and a part of the air cooled by the indoor evaporator 18 is reheated by the indoor condenser 12, so that the air temperature-adjusted to be close to the target outlet temperature TAO is blown into the vehicle interior, whereby cooling of the vehicle interior can be performed. Further, the battery 80 can be cooled by the cooling heat exchange unit 52.

(6) Series dehumidification heating cooling mode

In the series dehumidification and heating cooling mode, the cooling expansion valve 14c is set to a throttle state that exhibits a refrigerant decompression function, as opposed to the above-described series dehumidification and heating mode.

Therefore, in the tandem dehumidification, heating and cooling mode, the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the heating expansion valve 14a, the outdoor heat exchanger 16, the check valve 17, the cooling expansion valve 14b, the indoor evaporator 18, the evaporation pressure adjusting valve 20, the accumulator 21, and the compressor 11, and the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the heating expansion valve 14a, the outdoor heat exchanger 16, the check valve 17, the cooling expansion valve 14c, the cooling heat exchange portion 52, the evaporation pressure adjusting valve 20, the accumulator 21, and the compressor 11.

That is, in the refrigeration cycle apparatus 10 in the tandem dehumidification, heating, and cooling mode, the refrigeration cycle apparatus 10 constitutes a refrigeration cycle in which the indoor condenser 12 functions as a radiator (in other words, a radiating portion) that radiates heat from the refrigerant discharged from the compressor 11, the heating expansion valve 14a functions as a pressure reducing portion, the refrigeration expansion valve 14b functions as a pressure reducing portion, the indoor evaporator 18 functions as an evaporator, the cooling expansion valve 14c connected in parallel to the refrigeration expansion valve 14b and the indoor evaporator 18 functions as a pressure reducing portion, and the cooling heat exchange portion 52 functions as an evaporator.

Further, when the saturation temperature of the refrigerant in the outdoor heat exchanger 16 is higher than the outside air temperature Tam, a cycle is configured in which the outdoor heat exchanger 16 functions as a radiator (in other words, a heat radiating portion). A cycle is configured in which the outdoor heat exchanger 16 functions as an evaporator when the saturation temperature of the refrigerant in the outdoor heat exchanger 16 is lower than the outside air temperature Tam.

Thereby, the air can be cooled by the indoor evaporator 18, and the air can be heated by the indoor condenser 12. Further, the battery 80 can be cooled by the cooling heat exchange unit 52.

Therefore, in the refrigeration cycle apparatus 10 in the tandem dehumidification heating and cooling mode, the air cooled and dehumidified by the indoor evaporator 18 is reheated by the indoor condenser 12 and blown into the vehicle interior, whereby dehumidification heating of the vehicle interior can be performed. At this time, by increasing the aperture mode KPN1, the heating capacity of the air in the indoor condenser 12 can be improved as in the series dehumidification and heating mode. Further, the battery 80 can be cooled by the cooling heat exchange unit 52.

(7) Parallel dehumidification heating cooling mode

In the parallel dehumidification and heating cooling mode, the cooling expansion valve 14c is in a throttle state that exhibits a refrigerant decompression function, as opposed to the parallel dehumidification and heating mode described above.

Therefore, in the refrigeration cycle apparatus 10 in the parallel dehumidification, heating and cooling mode, the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the heating expansion valve 14a, the outdoor heat exchanger 16, the heating passage 22b, the accumulator 21, and the compressor 11, and the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the bypass passage 22a, the refrigeration expansion valve 14b, the indoor evaporator 18, the evaporation pressure control valve 20, the accumulator 21, and the compressor 11, and further, the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the bypass passage 22a, the cooling expansion valve 14c, the cooling heat exchange portion 52, the evaporation pressure control valve 20, the accumulator 21, and the compressor 11.

That is, in the refrigeration cycle apparatus 10 in the parallel dehumidification, heating, and cooling mode, the refrigeration cycle apparatus 10 constitutes a refrigeration cycle in which the indoor condenser 12 functions as a radiator (in other words, a radiating portion) that radiates heat from the refrigerant discharged from the compressor 11, the heating expansion valve 14a functions as a pressure reducing portion, the outdoor heat exchanger 16 functions as an evaporator, the refrigeration expansion valve 14b connected in parallel to the heating expansion valve 14a and the outdoor heat exchanger 16 functions as a pressure reducing portion, the indoor evaporator 18 functions as an evaporator, and further, the cooling expansion valve 14c connected in parallel to the heating expansion valve 14a and the outdoor heat exchanger 16 functions as a pressure reducing portion, and the cooling heat exchanging portion 52 functions as an evaporator.

Thereby, the air can be cooled by the indoor evaporator 18, and the air can be heated by the indoor condenser 12. Further, the battery 80 can be cooled by the cooling heat exchange unit 52.

Therefore, in the vehicle air conditioner 1 in the parallel dehumidification heating cooling mode, the air cooled and dehumidified by the indoor evaporator 18 is reheated by the indoor condenser 12 and blown into the vehicle interior, and dehumidification heating of the vehicle interior can be performed. At this time, by making the refrigerant evaporation temperature in the outdoor heat exchanger 16 lower than the refrigerant evaporation temperature in the indoor evaporator 18, the air can be reheated with a higher heating capacity than in the series dehumidification heating cooling mode.

Further, the battery 80 can be cooled by the cooling heat exchange unit 52.

(8) Heating and cooling mode

In the heating/cooling mode, the heating expansion valve 14a is fully opened, the cooling expansion valve 14b is fully closed, the cooling expansion valve 14c is throttled, the dehumidification on-off valve 15a is closed, and the heating on-off valve 15b is closed.

Therefore, in the refrigeration cycle apparatus 10 in the heating/cooling mode, a vapor compression refrigeration cycle is configured in which the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the heating expansion valve 14a, the outdoor heat exchanger 16, the check valve 17, the cooling expansion valve 14c, the cooling heat exchange portion 52, the evaporation pressure control valve 20, the accumulator 21, and the compressor 11.

That is, in the refrigeration cycle apparatus 10 in the heating and cooling mode, the indoor condenser 12 and the outdoor heat exchanger 16 constitute a vapor compression refrigeration cycle in which the refrigerant discharged from the compressor 11 functions as a radiator (in other words, a heat radiating portion), the cooling expansion valve 14c functions as a decompression portion that decompresses the refrigerant, and the cooling heat exchange portion 52 functions as an evaporator.

Thereby, the air can be heated by the indoor condenser 12, and the battery 80 can be cooled by the cooling heat exchange unit 52.

Therefore, in the air conditioner 1 for a vehicle in the heating and cooling mode, the air heated by the indoor condenser 12 is blown into the vehicle interior, so that the heating in the vehicle interior can be performed. Further, the battery 80 can be cooled by the cooling heat exchange unit 52.

(9) Heating series cooling mode

In the heating-series cooling mode, the heating expansion valve 14a is in a throttled state, the cooling expansion valve 14b is in a fully closed state, the cooling expansion valve 14c is in a throttled state, the dehumidification on-off valve 15a is closed, and the heating on-off valve 15b is closed.

Therefore, in the refrigeration cycle apparatus 10 in the heating-series cooling mode, a vapor compression refrigeration cycle is configured in which the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the heating expansion valve 14a, the outdoor heat exchanger 16, the check valve 17, the cooling expansion valve 14c, the cooling heat exchange portion 52, the evaporation pressure control valve 20, the accumulator 21, and the compressor 11.

That is, in the refrigeration cycle apparatus 10 in the heating-series cooling mode, the indoor condenser 12 functions as a radiator (in other words, a radiating portion) that radiates heat from the refrigerant discharged from the compressor 11, the heating expansion valve 14a and the cooling expansion valve 14c function as pressure reducing portions, and the cooling heat exchanging portion 52 functions as an evaporator.

Further, a cycle is configured in which the outdoor heat exchanger 16 functions as a radiator (in other words, a heat radiating portion) when the saturation temperature of the refrigerant in the outdoor heat exchanger 16 is higher than the outside air temperature Tam. A cycle is configured in which the outdoor heat exchanger 16 functions as an evaporator when the saturation temperature of the refrigerant in the outdoor heat exchanger 16 is lower than the outside air temperature Tam.

Thereby, the air can be heated by the indoor condenser 12, and the battery 80 can be cooled by the cooling heat exchange unit 52.

Therefore, in the air conditioner 1 for a vehicle in the heating-serial cooling mode, the air heated by the indoor condenser 12 is blown into the vehicle interior, so that the heating of the vehicle interior can be performed. Further, the battery 80 can be cooled by the cooling heat exchange unit 52.

(10) Heating parallel cooling mode

In the heating parallel cooling mode, the heating expansion valve 14a is in a throttled state, the cooling expansion valve 14b is in a fully closed state, the cooling expansion valve 14c is in a throttled state, the dehumidification on-off valve 15a is opened, and the heating on-off valve 15b is opened.

Further, a control signal or a control voltage is outputted to each control target device to obtain the control state determined in the above step, and the process returns to the initial step.

Therefore, in the refrigeration cycle apparatus 10 in the heating-parallel cooling mode, a refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the heating expansion valve 14a, the outdoor heat exchanger 16, the heating passage 22b, the accumulator 21, and the compressor 11, and the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the bypass passage 22a, the cooling expansion valve 14c, the cooling heat exchange portion 52, the evaporation pressure adjusting valve 20, the accumulator 21, and the compressor 11.

That is, in the refrigeration cycle apparatus 10 in the parallel heating and cooling mode, the refrigeration cycle is configured such that the indoor condenser 12 functions as a radiator (in other words, a radiating portion) that radiates heat from the refrigerant discharged from the compressor 11, the heating expansion valve 14a functions as a pressure reducing portion, the outdoor heat exchanger 16 functions as an evaporator, the cooling expansion valve 14c connected in parallel to the heating expansion valve 14a and the outdoor heat exchanger 16 functions as a pressure reducing portion, and the cooling heat exchange portion 52 functions as an evaporator.

Thereby, the air can be heated by the indoor condenser 12, and the battery 80 can be cooled by the cooling heat exchange unit 52.

Therefore, in the air conditioner 1 for a vehicle in the heating parallel cooling mode, the air heated by the indoor condenser 12 is blown into the vehicle interior, so that the heating in the vehicle interior can be performed. Further, the battery 80 can be cooled by the cooling heat exchange unit 52.

(11) Cooling mode

In the cooling mode, the expansion valve 14a for heating is fully opened, the expansion valve 14b for cooling is fully closed, the expansion valve 14c for cooling is throttled, the on-off valve 15a for dehumidification is closed, and the on-off valve 15b for heating is closed.

Therefore, in the refrigeration cycle apparatus 10 in the cooling mode, a vapor compression refrigeration cycle is configured in which the refrigerant circulates in the order of the compressor 11, the indoor condenser 12, the heating expansion valve 14a, the outdoor heat exchanger 16, the check valve 17, the cooling expansion valve 14c, the cooling heat exchange portion 52, the evaporation pressure adjusting valve 20, the accumulator 21, and the compressor 11.

That is, in the refrigeration cycle apparatus 10 in the cooling mode, the outdoor heat exchanger 16 is configured as a vapor compression refrigeration cycle in which the refrigerant discharged from the compressor 11 is allowed to radiate heat (in other words, a radiating portion), the cooling expansion valve 14c is allowed to function as a decompression portion, and the cooling heat exchange portion 52 is allowed to function as an evaporator. Thereby, the battery 80 can be cooled by the cooling heat exchange unit 52.

As described above, in the refrigeration cycle apparatus 10 of the present embodiment, various operation modes can be switched. Thus, in the vehicle air conditioner 1, the temperature of the battery 80 can be appropriately adjusted, and comfortable air conditioning in the vehicle interior can be achieved.

As described above, since the liquid refrigerant may be stored in the compressor 11 during the stop of the refrigeration cycle apparatus 10, if the refrigeration cycle apparatus 10 is started in a state in which the liquid refrigerant is stored in the compressor 11 (that is, if the compressor 11 is started), vibration and noise due to discharge pulsation of the compressor 11 are generated.

In view of this, the circulation control device 60 executes a control program for discharging the liquid refrigerant stored in the compressor 11 at the time of starting the refrigeration cycle device 10. A control routine for discharging liquid refrigerant from the compressor 11 will be described with reference to fig. 5. Each control step shown in the flowchart of fig. 5 is a function implementation unit included in the circulation control device 60.

The control routine is executed when an ignition switch of the vehicle (i.e., a start switch of the vehicle system) is operated from off to on.

First, in step S300 of fig. 5, it is determined whether it is necessary to discharge the liquid refrigerant from the compressor 11. In this example, when the elapsed time since the previous stop of the compressor 11 is one hour or more, it is determined that it is necessary to discharge the liquid refrigerant from the compressor 11.

If it is determined in step S300 that the liquid refrigerant does not need to be discharged, the routine proceeds to step S370, where normal control is performed. That is, the liquid discharge control is not performed. The initial opening K0 of the heating expansion valve 14a in normal control is set to about 2 times the opening of the final balance point.

If it is determined in step S300 that it is necessary to discharge the liquid refrigerant, the flow advances to S310, where it is determined whether the current operation mode is a heating mode, a heating cooling mode, a heating serial cooling mode, or a heating parallel cooling mode, a serial dehumidification heating mode, or a parallel dehumidification heating mode, or a cooling mode, a cooling mode, or a cooling mode.

If it is determined in step S310 that the current operation mode is the heating mode, the heating/cooling mode, the heating/series-cooling mode, or the heating/parallel-cooling mode, the flow proceeds to step S320, and the opening degree of the heating expansion valve 14a is set to the liquid discharge opening degree kα, which is larger than the initial opening degree in the normal control. For example, as shown in fig. 6, the liquid discharge opening degree kα of the expansion valve 14a for heating is 2 to 4 times the initial opening degree K0 at the time of normal control.

In the next step S330, it is determined whether or not the cumulative time of the operation in which the opening degree of the expansion valve 14a for heating is enlarged (hereinafter referred to as the opening degree enlarging operation of the expansion valve 14a for heating) is equal to or longer than the first cumulative time t 1. When it is determined that the integrated time of the opening expansion operation of the heating expansion valve 14a is not equal to or longer than the first integrated time t1, the routine returns to step S310. When it is determined that the cumulative time of the opening expansion operation of the heating expansion valve 14a is equal to or longer than the first cumulative time t1, the flow advances to step S340.

In step S340, after the opening degree of the expansion valve 14a for heating is gradually changed (that is, the opening degree of the expansion valve 14a for heating is gradually throttled) and returned to the initial opening degree K0, the routine proceeds to step S370 and shifts to normal control. For example, as shown in fig. 7, the opening of the heating expansion valve 14a is reduced by a predetermined amount Δk by a gradual change time tc.

If it is determined in step S310 that the current operation mode is the serial dehumidification and heating mode or the parallel dehumidification and heating mode, the flow proceeds to step S350, and the operation mode is switched to the cooling mode.

In the next step S360, it is determined whether or not the integrated time in the current operation mode (i.e., the cooling mode) is equal to or longer than the second integrated time t 2. If it is determined in step S360 that the integrated time in the current operation mode (i.e., the cooling mode) is not equal to or longer than the second integrated time t2, the routine returns to step S310.

If it is determined in step S360 that the integrated time in the current operation mode (i.e., the cooling mode) is equal to or longer than the second integrated time t2, the routine proceeds to step S370, and the routine proceeds to normal control.

If it is determined in step S310 that the current operation mode is the cooling mode, or the cooling mode, the flow proceeds to step S360. If it is determined in step S360 that the integrated time in the current operation mode is not equal to or longer than the second integrated time t2, the routine returns to step S310.

If it is determined in step S360 that the integrated time in the current operation mode is equal to or longer than the second integrated time t2, the routine proceeds to step S370, where the routine proceeds to normal control.

Fig. 6 is a graph illustrating the opening degree of the expansion valve 14a for heating in the liquid discharge control in the heating mode, the heating cooling mode, the heating series cooling mode, or the heating parallel cooling mode. In general, the initial opening K0 of the heating expansion valve 14a is set to about 2 times the equivalent diameter of the final equilibrium point in view of the convergence time and the cycle stability on the premise that the compressor 11 discharges the gas refrigerant.

The opening degree of the expansion valve 14a for heating at the time of liquid discharge control, that is, the liquid discharge opening degree kα is set to 2 to 4 times the equivalent diameter of the final balance point. This can increase the discharge amount of the liquid refrigerant from the heating expansion valve 14a, prevent the high-pressure volume from being filled with liquid, and complete the liquid discharge control in a short time (specifically, within the first cumulative time t 1) in which no deviation in performance is perceived by the occupant.

Fig. 7 is a timing chart showing an example of a change in the opening degree of the heating expansion valve 14a during the liquid discharge control in the heating mode, and shows an example of a case where the liquid discharge control is executed simultaneously with the start of the compressor 11.

Immediately after the start of the compressor 11, the opening degree of the heating expansion valve 14a is set to the liquid discharge opening degree kα, and is enlarged from the initial opening degree K0 at the time of normal control. The opening expansion operation of the heating expansion valve 14a is performed at the first integration time t 1. As a result, since the liquid refrigerant discharged from the compressor 11 can be received by the high-volume outdoor heat exchanger 16, the liquid refrigerant stored in the high-pressure circuit (i.e., the refrigerant circuit from the compressor 11 to the heating expansion valve 14 a) in the cycle at the time of starting is discharged in one stroke. As a result, the phenomenon that the circulating high-pressure circuit is filled with liquid is avoided.

At this time, when the amount of refrigerant in the cycle is sufficiently large, the refrigerant discharged from the high-pressure circuit in a short period of time accumulates in the accumulator 21, and overflows, and the compressor 11 sucks in the liquid refrigerant, so that the amount of discharged refrigerant increases sharply.

Here, if the opening expansion operation of the heating expansion valve 14a is completed and the opening of the heating expansion valve 14a is immediately throttled, the discharged refrigerant cannot be discharged, and the amount of refrigerant in the high-pressure circuit increases and is filled with liquid again, thereby generating abnormal vibration and abnormal noise of the piping due to discharge pulsation of the compressor 11.

In view of this, by gradually changing the opening degree of the heating expansion valve 14a at the end of the opening degree expansion operation of the heating expansion valve 14a, it is possible to suppress the overflow from the accumulator 21 while gradually maintaining the refrigerant on the high pressure side, and to approximate the refrigerant distribution at the time of final heating.

The rate of gradual change of the opening of the expansion valve 14a for heating is determined to be the optimum point based on the refrigerant flow rate characteristics of the compressor 11 when the liquid is sucked and the refrigerant flow rate characteristics determined by the equivalent diameter of the expansion valve 14a for heating. In this example, the gradual change rate of the opening degree of the heating expansion valve 14a is set by Δk/tc.

As described above, when the compressor 11 is started in the heating mode, the heating cooling mode, the heating series cooling mode, or the heating parallel cooling mode, the liquid filling of the high-pressure side circuit can be avoided, and the distribution of the amount of refrigerant in the cycle can be made gradually closer to the normal operation.

Next, liquid discharge control in the parallel dehumidification and heating mode or the serial dehumidification and heating mode will be described. In the parallel dehumidification and heating mode, the heating expansion valve 14a is throttled, and in the series dehumidification and heating mode, the heating expansion valve 14a and the cooling expansion valve 14b are throttled, so that liquid refrigerant discharge control is performed in order to prevent abnormal noise from being generated when the high-pressure circuit is filled with liquid, similarly to the heating mode. Specifically, since the heating expansion valve 14a is fully opened by switching to the cooling mode for a predetermined period of time, the liquid refrigerant discharged from the high-pressure circuit can be received by the high-volume outdoor heat exchanger 16, and therefore both of ensuring dehumidification performance and suppressing discharge pulsation can be achieved.

In the present embodiment described above, when it is determined that the liquid refrigerant is stored in the compressor 11 at the time of starting the compressor 11, the circulation control device 60 performs liquid discharge control for promoting discharge of the liquid refrigerant stored from the compressor 11 to the heating expansion valve 14 a.

In this way, when the compressor 11 is started, the discharge of the liquid refrigerant stored from the compressor 11 to the heating expansion valve 14a is promoted, and therefore, the discharge pulsation of the compressor 11 can be suppressed. Therefore, the occurrence of vibration and noise due to discharge pulsation of the compressor 11 can be suppressed.

Since the discharge pulsation of the compressor 11 is suppressed by the control, the rise in cost and the deterioration of mountability can be avoided.

In the present embodiment, the liquid discharge control is a control in which the opening degree of the heating expansion valve 14a is set to a liquid discharge opening degree kα, which is an opening degree that is enlarged from the initial opening degree K0 of the normal opening degree. Accordingly, since the liquid refrigerant easily passes through the heating expansion valve 14a when the compressor 11 is started, the discharge of the liquid refrigerant stored from the compressor 11 to the heating expansion valve 14a can be reliably promoted.

Specifically, the liquid discharge opening degree kα is preferably 2 to 4 times the initial opening degree K0. Since the liquid refrigerant easily and reliably passes through the heating expansion valve 14a when the compressor 11 is started, the discharge of the liquid refrigerant stored from the compressor 11 to the heating expansion valve 14a can be reliably promoted.

In the present embodiment, the circulation control device 60 gradually returns the opening degree of the heating expansion valve 14a to the normal opening degree when the liquid discharge control is completed. This can suppress the refrigerant circuit from the compressor 11 to the heating expansion valve 14a from being filled with the liquid refrigerant when the liquid discharge control is completed, and thus can suppress the occurrence of discharge pulsation of the compressor 11 when the liquid discharge control is completed.

In the present embodiment, the liquid discharge control when the compressor 11 is started in the parallel dehumidification heating mode or the serial dehumidification heating mode is control to switch from the parallel dehumidification heating mode or the serial dehumidification heating mode to the cooling mode.

Accordingly, since the liquid refrigerant easily flows into the outdoor heat exchanger 16 having a large refrigerant volume when the compressor 11 is started, the discharge of the liquid refrigerant stored from the compressor 11 to the heating expansion valve 14a can be reliably promoted. The parallel dehumidification heating mode or the series dehumidification heating mode is a first operation mode, and the parallel dehumidification heating mode or the series dehumidification heating mode is a second operation mode.

In the present embodiment, the circulation control device 60 starts the liquid discharge control, and then ends the liquid discharge control after a predetermined time elapses. This makes it possible to properly end the liquid discharge control with a simple configuration.

(second embodiment)

In the above embodiment, the opening degree of the heating expansion valve 14a is enlarged from the normal opening degree at the time of the liquid discharge control, but in the present embodiment, the liquid discharge opening/closing valve 15c shown in fig. 8 is opened at the time of the liquid discharge control.

The liquid discharge opening/closing valve 15c is a liquid discharge opening/closing portion that opens and closes the refrigerant passage of the liquid discharge passage portion 22 c. The liquid discharge on-off valve 15c is a solenoid valve having the same basic structure as the on-off valve 15a for dehumidification. The operation of the liquid discharge opening/closing valve 15c is controlled by a control voltage output from the circulation control device 60.

The liquid discharge passage portion 22c forms a refrigerant passage through which the refrigerant flows bypassing the heating expansion valve 14 a. One end of the liquid discharge passage portion 22c is connected to a refrigerant passage between the first three-way joint 13a and the heating expansion valve 14a via a seventh three-way joint 13 g. The other end of the liquid discharge passage portion 22c is connected to a refrigerant passage between the heating expansion valve 14a and the outdoor heat exchanger 16 via an eighth three-way joint 13 h.

The circulation control device 60 closes the liquid discharge opening/closing valve 15c during normal control, and opens the liquid discharge opening/closing valve 15c during liquid discharge control. Thus, during normal control, the refrigerant flows through the heating expansion valve 14a, but the refrigerant does not flow through the liquid discharge passage portion 22c.

On the other hand, during the liquid discharge control, the refrigerant flows through the liquid discharge passage portion 22c having a small flow path resistance, but the refrigerant hardly flows through the heating expansion valve 14a having a large flow path resistance. This can increase the discharge amount of the liquid refrigerant from the compressor 11 and the indoor condenser 12, and prevent the liquid from filling the high-pressure volume.

In the present embodiment, when the compressor 11 is started, the circulation control device 60 determines that the liquid refrigerant is stored in the compressor 11, and controls the liquid discharge opening/closing valve 15c so as to open the liquid discharge passage portion 22c. Accordingly, since the liquid refrigerant passes through the liquid discharge passage portion 22c at the time of starting the compressor 11, the discharge of the liquid refrigerant stored in the compressor 11 can be reliably promoted.

The present invention is not limited to the above-described embodiments, and various modifications can be made as follows within the scope not departing from the gist of the present invention.

In step S300 of the above embodiment, when the elapsed time since the previous stop of the compressor 11 is one hour or more, it is determined that the liquid refrigerant needs to be discharged from the compressor 11, but the determination method of whether the liquid refrigerant needs to be discharged from the compressor 11 is not limited thereto.

For example, a liquid level sensor that detects the liquid level of the liquid refrigerant may be disposed inside the compressor 11, and when the liquid level detected by the liquid level sensor is equal to or higher than a predetermined value, it may be determined that the liquid refrigerant needs to be discharged from the compressor 11.

For example, it may be determined whether or not the liquid refrigerant needs to be discharged from the compressor 11 based on a change in the outside air temperature during the stop of the compressor 11. Specifically, when there is a change in the outside air temperature such as an increase in the outside air temperature from late night to early morning in winter, it is determined that the liquid refrigerant needs to be discharged from the compressor 11.

In step S340 of the first embodiment, when the liquid discharge control is completed, the opening degree of the expansion valve 14a for heating is gradually changed to suppress the overflow from the accumulator 21, but if the refrigerant volume of the accumulator 21 is sufficiently large, the opening degree of the expansion valve 14a for heating does not need to be gradually changed.

At the end of the liquid discharge control, the opening degree of the heating expansion valve 14a is throttled or returned to the normal opening degree immediately, and as long as the refrigerant volume of the accumulator 21 is large enough to receive all the liquid refrigerant, the overflow from the accumulator 21 can be suppressed.

That is, if the total of the refrigerant volume of the accumulator 21 and the refrigerant volume from the compressor 11 to the heating expansion valve 14a is larger than the total liquid refrigerant volume at the time of starting the compressor 11, it is possible to reliably suppress the liquid-phase refrigerant from being filled up to the decompression section from the compressor 11 at the time of ending the liquid discharge control.

In step S310 of the first embodiment, when it is determined that the current operation mode is the dehumidification heating mode (parallel dehumidification heating mode or series dehumidification heating mode), the operation is switched to the cooling mode, whereby the dehumidification performance is prioritized over the heating performance and the liquid refrigerant is discharged from the compressor 11.

In contrast, when it is determined that the current operation mode is the dehumidification and heating mode (parallel dehumidification and heating mode or series dehumidification and heating mode), the opening degree of the heating expansion valve 14a may be increased compared with the normal opening degree in the same manner as in the heating mode, whereby the heating performance is prioritized over the dehumidification performance and the liquid refrigerant is discharged from the compressor 11.

In the second embodiment, a fixed orifice formed of an orifice, a capillary tube, or the like may be arranged instead of the heating expansion valve 14 a.

In the above-described embodiment, the refrigeration cycle apparatus 10 that can be switched to a plurality of operation modes has been described, but the switching of the operation modes of the refrigeration cycle apparatus 10 is not limited to this. The detailed control of each operation mode is not limited to the control disclosed in the above embodiment. For example, the air blowing mode described in step S260 may be a stop mode in which not only the compressor 11 but also the blower 32 is stopped.

The constituent devices of the refrigeration cycle apparatus are not limited to those disclosed in the above embodiments. In order to achieve the above-described effects, integration of a plurality of circulation constituent devices and the like may be performed. For example, a four-way joint structure may be employed in which the second three-way joint 13b and the fifth three-way joint 13e are integrated. Further, as the expansion valve 14b for cooling and the expansion valve 14c for cooling, a structure in which an electric expansion valve having no fully closed function is directly connected to an opening/closing valve may be employed.

In the above embodiment, the example in which R1234yf is used as the refrigerant is described, but the refrigerant is not limited to this. For example, R134a, R600a, R410A, R404A, R, R407C, etc. may be employed. Alternatively, a mixed refrigerant or the like in which a plurality of these refrigerants are mixed may be used. Further, carbon dioxide may be used as the refrigerant to constitute a supercritical refrigeration cycle in which the high-pressure side refrigerant pressure is equal to or higher than the critical pressure of the refrigerant.

In the above embodiment, the air is heated by exchanging heat between the refrigerant and the air by the indoor condenser 12, but the air may be heated by the refrigerant via a heat medium.

Specifically, a refrigerant heat medium heat exchanger, a high-temperature heat medium circuit, and a heater core may be disposed in place of the indoor condenser 12. The refrigerant heat medium heat exchanger is a heating heat exchanger that exchanges heat between the high-temperature and high-pressure refrigerant discharged from the compressor 11 and the heat medium, condenses the refrigerant, and heats the heat medium. The high-temperature heat medium circuit is a heat medium circulation circuit that circulates a side heat medium heated by the refrigerant heat medium heat exchanger. As the heat medium, a solution containing ethylene glycol, dimethylpolysiloxane, nanofluid, or the like, an antifreeze, or the like can be used. The heater core is a heat exchanger for heating the air by exchanging heat between the heat medium heated by the refrigerant heat medium heat exchanger and the air passing through the indoor evaporator 18.

In the above embodiment, the battery 80 is directly cooled by the cooling heat exchange portion 52, but the battery 80 may be cooled by a refrigerant via a heat medium.

Specifically, a chiller, a low-temperature heat medium circuit, and a battery cooler may be disposed in place of the cooling heat exchange unit 52. The chiller is a cooling heat exchanger that exchanges heat between the low-pressure refrigerant depressurized by the cooling expansion valve 14c and a heat medium, evaporates the refrigerant, and cools the heat medium. The low-temperature heat medium circuit is a heat medium circulation circuit that circulates a heat medium cooled by a chiller. As the heat medium, a solution containing ethylene glycol, dimethylpolysiloxane, nanofluid, or the like, an antifreeze, or the like may be used. The battery cooler is a cooler that cools the battery 80 using the heat medium cooled by the chiller.

In the above embodiments, the example in which the cooling target object different from air in the refrigeration cycle apparatus 10 is the battery 80 was described, but the cooling target object is not limited to this. The present invention may be an electric device that generates heat during operation, such as an inverter that converts dc current and ac current, a charger that charges the battery 80, and a motor generator that outputs driving force for traveling by supplying electric power and generates regenerative electric power during deceleration or the like.

In the above embodiments, the refrigeration cycle apparatus 10 is applied to the vehicle air conditioner 1, but the application of the refrigeration cycle apparatus 10 is not limited to this. For example, the present invention can be applied to an air conditioner or the like that appropriately adjusts the temperature of a stationary battery and performs a battery cooling function for indoor air conditioning.

The present invention has been described with reference to the embodiments, but it should be understood that the present invention is not limited to the embodiments and configurations. The present invention also includes various modifications and modifications within the equivalent range. It is to be noted that various combinations and modes, including only one element or other combinations and modes including one element or more or a plurality of elements or less, are within the scope and spirit of the present invention.

Claims (8)

1. A refrigeration cycle device is characterized by comprising:

a compressor (11) that sucks, compresses, and discharges a refrigerant;

a radiator (12) that radiates heat from the refrigerant discharged from the compressor;

a decompression unit (14 a) that decompresses the refrigerant that has been radiated by the radiator; and

a control unit (60) for controlling the opening degree of the pressure reducing unit to be a normal opening degree,

the control unit determines that the liquid phase of the refrigerant is stored in the compressor when the compressor is started, and performs liquid discharge control that promotes discharge of the liquid phase of the refrigerant stored from the compressor to the pressure reducing unit.

2. A refrigeration cycle device according to claim 1, wherein,

the liquid discharge control is a control in which the opening degree of the pressure reducing portion is set to a liquid discharge opening degree (kα) which is an opening degree that is larger than an initial opening degree (K0) of the normal opening degree.

3. A refrigeration cycle device according to claim 2, wherein,

the liquid discharge opening is 2 to 4 times the initial opening.

4. A refrigeration cycle device according to claim 2 or 3, wherein,

The control unit gradually returns the opening degree of the pressure reducing unit to the normal opening degree when the liquid discharge control is ended.

5. A refrigeration cycle device according to claim 2 or 3, wherein,

comprises a liquid storage part (21) for separating the gas and liquid of the refrigerant sucked into the compressor and storing the separated liquid-phase refrigerant,

the total of the refrigerant volume of the liquid storage portion and the refrigerant volume from the compressor to the pressure reducing portion is larger than the total volume of the refrigerant in the liquid phase at the time of starting the compressor.

6. A refrigeration cycle device according to claim 1, wherein,

comprises a high-volume heat exchanger (16) which exchanges heat with the refrigerant and has a larger refrigerant volume than the radiator,

the control portion controls the pressure reducing portion in a first operation mode to absorb heat from the refrigerant by the high-volume heat exchanger, controls the pressure reducing portion in a second operation mode to radiate heat from the refrigerant by the Gao Rongji heat exchanger,

the liquid discharge control when starting the compressor in the first operation mode is control to switch from the first operation mode to the second operation mode.

7. A refrigeration cycle device is characterized by comprising:

a compressor (11) that sucks, compresses, and discharges a refrigerant;

a radiator (12) that radiates heat from the refrigerant discharged from the compressor;

a decompression unit (14 a) that decompresses the refrigerant that has been radiated by the radiator;

a liquid discharge passage portion (22 c) that forms a refrigerant passage through which the refrigerant flowing out of the radiator flows while bypassing the pressure reducing portion;

a liquid discharge opening/closing unit (15 c) that opens and closes the liquid discharge passage; and

and a control unit (60) that, when the compressor is started, determines that the liquid-phase refrigerant is stored in the compressor, performs liquid discharge control for controlling the liquid discharge opening/closing unit to open the liquid discharge passage.

8. A refrigeration cycle device according to any one of claims 1 to 7, wherein,

the control unit starts the liquid discharge control and then ends the liquid discharge control after a predetermined time has elapsed.