Refrigeration cycle device

Abstract

The present invention improves the cycle performance of a refrigeration cycle device having a reservoir. The present invention is provided with: a compressor (31) that sucks in, compresses and discharges a refrigerant; a radiator (15) that dissipates heat from the refrigerant discharged from the compressor (31); a pressure reduction unit (32) that reduces the pressure of the refrigerant after heat dissipation by the radiator (15); an evaporation unit (14) that evaporates the refrigerant decompressed by the decompression unit (32); an accumulator that separates gas and liquid of the refrigerant evaporated in the evaporation unit (14) and causes the refrigerant in a gas phase to flow out; and a superheating unit (34) that superheats the refrigerant flowing out from the reservoir (33) by exchanging heat with a heat medium having a higher temperature than the refrigerant flowing out from the reservoir (33).

Description

[0001] Cross-reference to related applications

[0002] This application is based on Japanese Patent Application No. 2022-142136 filed on September 7, 2022, and the contents thereof are cited herein. Technical Field

[0003] The present disclosure relates to a refrigeration cycle device having a liquid accumulator. Background Art

[0004] Conventionally, a refrigeration cycle device in which the inlet side of a accumulator is connected to the outlet side of an evaporator is described in Patent Document 1. The accumulator is a gas-liquid separator that separates the gas and liquid of the refrigerant flowing into the accumulator and stores the excess refrigerant in the cycle.

[0005] In this prior art, refrigeration oil is mixed in the refrigerant, and part of the refrigeration oil circulates together with the refrigerant in the cycle, thereby ensuring the lubricity of the compressor. Therefore, the refrigerant at the evaporator outlet has a certain amount of dryness.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2016-156554

[0009] In the above-mentioned prior art, although the refrigerant at the evaporator outlet is operated in such a manner that the dryness is certain, the superheat of the refrigerant at the evaporator outlet is not controlled. In contrast, in a refrigeration cycle device having a receiver on the outlet side of the radiator, the superheat of the refrigerant at the evaporator outlet is controlled. The receiver is a gas-liquid separator that separates the gas and liquid of the refrigerant flowing into it and stores the remaining refrigerant in the cycle.

[0010] In a refrigeration cycle device having a receiver, the refrigerant at the outlet of the evaporator is controlled to have a certain degree of superheat, so that the enthalpy difference of the evaporator is large. As a result, the cycle performance can be improved.

[0011] On the other hand, in a refrigeration cycle device having an accumulator, since the superheat of the refrigerant at the evaporator outlet is not controlled, it is difficult to increase the enthalpy difference of the evaporator. As a result, it is also difficult to improve the cycle performance. Summary of the invention

[0012] The present disclosure is made in view of the above-mentioned problems, and an object of the present disclosure is to improve the cycle performance of a refrigeration cycle device having a liquid accumulator.

[0013] A refrigeration cycle device according to one aspect of the present disclosure includes a compressor, a radiator, a decompression unit, an evaporation unit, a accumulator, and a superheating unit.

[0014] The compressor sucks in the refrigerant, compresses it, and discharges it. The radiator dissipates the heat of the refrigerant discharged from the compressor. The decompression unit decompresses the refrigerant after the heat is dissipated by the radiator. The evaporation unit evaporates the refrigerant after the decompression by the decompression unit. The accumulator separates the refrigerant evaporated in the evaporation unit into gas and liquid and discharges the gas phase refrigerant. The superheating unit superheats the refrigerant flowing out of the accumulator by heat exchange with a heat medium having a higher temperature than the refrigerant flowing out of the accumulator.

[0015] According to this, the refrigerant flowing out of the accumulator is superheated in the superheating section, thereby increasing the enthalpy difference at low pressure (ie, the enthalpy difference between the evaporation section and the superheating section), thereby improving the cycle performance (so-called COP). BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings.

[0017] Figure 1 It is a diagram showing the overall configuration of a vehicle air conditioning device according to the first embodiment.

[0018] Figure 2 It is a schematic structural diagram of the heat exchanger unit according to the first embodiment.

[0019] Figure 3 It is a schematic structural diagram of the indoor air conditioning unit according to the first embodiment.

[0020] Figure 4 1 is a block diagram showing an electrical control unit of the vehicle air conditioning system according to the first embodiment.

[0021] Figure 5 This is a Mollier diagram showing the state change of the refrigerant in the refrigeration cycle of the first embodiment.

[0022] Figure 6 It is a diagram showing the overall configuration of a vehicle air conditioning device according to a second embodiment.

[0023] Figure 7 It is a schematic structural diagram of a part of the refrigeration cycle of the second embodiment.

[0024] Figure 8 It is a diagram showing the overall configuration of a vehicle air conditioning system according to a third embodiment. DETAILED DESCRIPTION

[0025] Hereinafter, a plurality of methods for implementing the present disclosure will be described with reference to the accompanying drawings. In each embodiment, sometimes the same reference numerals are given to portions corresponding to matters described in a previous embodiment, and repeated descriptions are omitted. In the case where only a portion of a structure is described in each embodiment, other embodiments described previously can be applied to other portions of the structure. Not only are combinations of parts that can be combined specifically indicated in each embodiment, but also embodiments can be partially combined with each other even if not indicated, as long as the combination does not particularly cause an obstruction.

[0026] (First Embodiment)

[0027] Figure 1 The vehicle air conditioning device 10 shown is used to adjust the interior space of the vehicle to an appropriate temperature. In this embodiment, the vehicle air conditioning device 10 is applied to an electric vehicle that obtains a driving force for the vehicle from a driving motor. The electric vehicle of this embodiment can charge the battery mounted on the vehicle (in other words, the on-board battery) with power supplied from an external power source (in other words, a commercial power source) when the vehicle is parked. As the battery, for example, a lithium-ion battery can be used.

[0028] The electric power stored in the battery is supplied not only to the electric motor for traveling but also to various vehicle-mounted devices represented by electric components constituting the vehicle air conditioner 10 .

[0029] The vehicle air conditioner 10 includes a low-temperature side pump 11 , a high-temperature side pump 12 , a low-temperature side radiator 13 , an evaporator 14 , a condenser 15 , a cooler core 16 , a heater core 17 , a switching valve 18 , a high-temperature side radiator 19 , and a flow control valve 20 .

[0030] The low temperature side pump 11 and the high temperature side pump 12 are electric pumps that suck and discharge cooling water (in other words, heat medium). Cooling water is a fluid that serves as a heat medium. In this embodiment, as cooling water, a liquid containing at least ethylene glycol, dimethylpolysiloxane or nanofluid; or an antifreeze liquid is used.

[0031] The low-temperature-side radiator 13 , the evaporator 14 , the condenser 15 , the cooler core 16 , the heater core 17 , and the high-temperature-side radiator 19 are cooling water circulation devices (in other words, heat medium circulation devices) through which cooling water flows.

[0032] The low temperature side radiator 13 is a cooling water outside air heat exchanger (in other words, a heat medium outside air heat exchanger) that performs heat exchange between cooling water and outside air (i.e., outside air of the vehicle). The low temperature side radiator 13 is arranged at the frontmost part of the vehicle. Outside air is blown to the low temperature side radiator 13 by the outdoor blower 21. When the vehicle is running, the running wind can contact the low temperature side radiator 13.

[0033] The outdoor air blower 21 is an air blowing unit that blows outside air toward the low-temperature side radiator 13. The outdoor air blower 21 is an electric air blower that drives a fan using an electric motor.

[0034] The evaporator 14 is a low-pressure heat exchanger (in other words, a heat exchanger for cooling the heat medium) that cools the cooling water by exchanging heat between the low-pressure refrigerant in the refrigeration cycle 30 and the cooling water. In the evaporator 14, the cooling water can be cooled to a temperature lower than that of the outside air.

[0035] The condenser 15 is a high-pressure-side heat exchanger (in other words, a heat exchanger for heating a heat medium) that heats the cooling water by exchanging heat between the high-pressure-side refrigerant of the refrigeration cycle 30 and the cooling water.

[0036] The refrigeration cycle 30 is a vapor compression refrigerator including a compressor 31, a condenser 15, an expansion valve 32, an evaporator 14, a liquid receiver 33, and a superheater 34. In the refrigeration cycle 30 of the present embodiment, a Freon-based refrigerant is used as a refrigerant, and a subcritical refrigeration cycle is constructed in which the refrigerant pressure on the high-pressure side does not exceed the critical pressure of the refrigerant.

[0037] The compressor 31 is an electric compressor driven by power supplied from a battery or a variable capacity compressor driven by a belt, and sucks in, compresses, and discharges the refrigerant of the refrigeration cycle 30. The condenser 15 is a condenser that condenses the high-pressure refrigerant discharged from the compressor 31 by exchanging heat with cooling water.

[0038] The expansion valve 32 is a decompression unit that decompresses and expands the liquid-phase refrigerant flowing out of the condenser 15. The evaporator 14 is an evaporator that evaporates the low-pressure refrigerant by exchanging heat with cooling water after the low-pressure refrigerant is decompressed and expanded by the expansion valve 32. The gas-phase refrigerant evaporated in the evaporator 14 is sucked into the compressor 31 and compressed.

[0039] The accumulator 33 is a gas-liquid separator that separates the gas-phase refrigerant flowing out of the evaporator 14 into liquid and allows the gas-phase refrigerant to flow out and stores the liquid-phase refrigerant as the remaining refrigerant. The superheater 34 is a heat exchanger that exchanges heat between the gas-phase refrigerant flowing out of the accumulator 33 and cooling water, and is a superheating unit that superheats the gas-phase refrigerant flowing out of the accumulator 33.

[0040] The cooler core 16 is an air cooling heat exchanger (in other words, a cooling heat exchanger) that cools the air by exchanging heat between the coolant in the low-temperature coolant circuit C1 and the air blown into the vehicle interior space (in other words, a cooling object). In the cooler core 16, the coolant absorbs heat from the air through sensible heat change. That is, in the cooler core 16, even if the coolant absorbs heat from the air, the coolant remains in a liquid phase without undergoing a phase change.

[0041] The heater core 17 is an air heating heat exchanger (in other words, a heat exchanger for heat medium heat dissipation) that heats the air by exchanging heat between the coolant in the high-temperature coolant circuit C2 and the air that has passed through the cooler core 16. In the heater core 17, the coolant dissipates heat to the air through sensible heat change. That is, in the heater core 17, even if the coolant dissipates heat to the air, the coolant remains in a liquid phase without undergoing a phase change.

[0042] The switching valve 18 is a switching unit that switches the flow of cooling water to the low-temperature side radiator 13 and the cooler core 16. The high-temperature side radiator 19 is a cooling water-to-air heat exchanger (in other words, a heat medium-to-air heat exchanger) that performs heat exchange between cooling water and the outside air. The flow control valve 20 is a flow ratio adjustment unit that adjusts the flow ratio of cooling water to the heater core 17 and the high-temperature side radiator 19. The switching valve 18 and the flow control valve 20 are composed of Figure 4 The control device 60 shown controls the control valve.

[0043] like Figure 1 As shown, the evaporator 14, the low temperature side pump 11, the low temperature side radiator 13, the cooler core 16 and the switching valve 18 are arranged in the low temperature cooling water circuit C1 (in other words, the low temperature heat medium circuit). The low temperature cooling water circuit C1 is a cooling water circuit configured so that low temperature cooling water (in other words, low temperature heat medium) circulates in the order of the low temperature side pump 11, the evaporator 14, the low temperature side radiator 13, the cooler core 16 and the low temperature side pump 11. The cooling water of the low temperature cooling water circuit C1 flows in parallel in the low temperature side radiator 13 and the cooler core 16.

[0044] The high temperature side pump 12, the condenser 15, the heater core 17, the high temperature side radiator 19 and the flow control valve 20 are arranged in the high temperature cooling water circuit C2 (in other words, the high temperature heat medium circuit). The high temperature cooling water circuit C2 is a cooling water circuit configured so that high temperature cooling water (in other words, high temperature heat medium) circulates in the order of the high temperature side pump 12, the heater core 17 and the high temperature side radiator 19, the condenser 15, and the high temperature side pump 12. The cooling water of the high temperature cooling water circuit C2 flows in parallel in the heater core 17 and the high temperature side radiator 19.

[0045] like Figure 2 As shown, the evaporator 14 , the accumulator 33 , and the superheater 34 are integrated to form a heat exchanger unit 35 .

[0046] The portion of the heat exchanger unit 35 that forms the evaporator 14 and the superheater 34 is a stacked heat exchanger. That is, the portion of the heat exchanger unit 35 that forms the evaporator 14 and the superheater 34 has a plurality of metal plate-like members. The plurality of plate-like members are stacked on each other, and a refrigerant flow path and a cooling water flow path are formed between the plate-like members.

[0047] The heat exchanger unit 35 is provided with a refrigerant inlet 35a, a refrigerant outlet 35b, a cooling water inlet 35c, and a cooling water outlet 35d. The refrigerant inlet 35a is a refrigerant inlet shared by the evaporator 14, the accumulator 33, and the superheater 34. The refrigerant outlet 35b is a refrigerant outlet shared by the evaporator 14, the accumulator 33, and the superheater 34. The cooling water inlet 35c is a cooling water inlet shared by the evaporator 14, the accumulator 33, and the superheater 34. The cooling water outlet 35d is a cooling water outlet shared by the evaporator 14, the accumulator 33, and the superheater 34.

[0048] exist Figure 2 In FIG. 1 , the solid arrows indicate the flow of the refrigerant in the refrigerant flow path. Figure 2 In FIG. 1 , the dotted arrows indicate the flow of cooling water in the cooling water flow path. The refrigerant flowing in from the refrigerant inlet 35a flows through the evaporator 14, flows into the accumulator 33, and is separated into gas and liquid. The separated gas-phase refrigerant flows in the superheater 34 and flows out from the refrigerant outlet 35b. The cooling water flowing in from the cooling water inlet 35c flows in series in the superheater 34 and the evaporator 14, and flows out from the cooling water outlet 35d.

[0049] In the refrigerant flow path of the evaporator 14, the flow of the refrigerant makes a U-turn. In the cooling water flow path of the evaporator 14, the flow of the cooling water makes a U-turn. In the evaporator 14 and the superheater 34, the flow direction of the refrigerant and the flow direction of the cooling water are opposite to each other. That is, in the evaporator 14 and the superheater 34, the flow of the refrigerant and the flow of the cooling water are opposite.

[0050] Next, use Figure 3 The indoor air conditioning unit 50 is described. The indoor air conditioning unit 50 is a unit that integrates a plurality of components in order to blow air adjusted to an appropriate temperature for air conditioning in the vehicle interior to an appropriate location in the vehicle interior. The indoor air conditioning unit 50 is arranged on the inner side of the instrument panel (so-called instrument panel) at the frontmost part of the vehicle interior.

[0051] The indoor air conditioning unit 50 is formed by accommodating an indoor blower 52, a cooler core 16, a heater core 17, etc. in an air conditioning case 51 forming an air passage. The air conditioning case 51 is formed of a resin (eg, polypropylene) having a certain degree of elasticity and excellent strength.

[0052] An inside / outside air switching device 53 is disposed at the most upstream side of the air flow of the air conditioning casing 51. The inside / outside air switching device 53 switches between introducing inside air (i.e., vehicle interior air) and outside air into the air conditioning casing 51. The operation of the inside / outside air switching device 53 is controlled by a control signal output from the control device 60.

[0053] An indoor blower 52 is disposed downstream of the indoor and outdoor air switching device 53. The indoor blower 52 is a blower that blows air sucked in through the indoor and outdoor air switching device 53 toward the vehicle interior. The rotation speed (i.e., air blowing capacity) of the indoor blower 52 is controlled by a control voltage output from the control device 60.

[0054] The cooler core 16 and the heater core 17 are arranged on the air flow downstream side of the indoor blower 52. The cooler core 16 is arranged on the air flow upstream side compared with the heater core 17. A cold air bypass passage 55 is formed in the air conditioning case 51 so that the air passing through the cooler core 16 bypasses the heater core 17 and flows.

[0055] An air mix door 54 is disposed in the air conditioning case 51 on the air flow downstream side of the cooler core 16 and the air flow upstream side of the heater core 17 and the cold air bypass passage 55 .

[0056] The air mix door 54 adjusts the volume ratio of the air passing through the heater core 17 and the air passing through the cold air bypass passage 55 after passing through the cooler core 16. The operation of the actuator for driving the air mix door 54 is controlled by a control signal output from the control device 60.

[0057] Therefore, in the indoor air conditioning unit 50 , by changing the opening degree of the air mix door 54 , the amount of heat exchange between the refrigerant and the air in the heater core 17 can be changed.

[0058] A mixing space 56 is disposed downstream of the heater core 17 and the cold air bypass passage 55 in the air flow. The mixing space 56 is a space where the air heated by the heater core 17 and the air that has passed through the cold air bypass passage 55 and is not heated are mixed.

[0059] Therefore, in the interior air conditioning unit 50 , the temperature of the air (ie, conditioned air) mixed in the mixing space 56 and blown into the vehicle interior can be adjusted by adjusting the opening degree of the air mix door 54 .

[0060] A plurality of openings (not shown) for blowing out the air-conditioned air toward various locations in the vehicle interior are formed at the most downstream portion of the air flow of the air-conditioning housing 51. A blow-out mode door (not shown) for opening and closing each of the openings is disposed at the plurality of openings. The operation of the actuator for driving the blow-out mode door is controlled by a control signal output from the control device 60.

[0061] Therefore, in the interior air conditioning unit 50, by switching the opening hole of the door to be opened and closed in the air outlet mode, conditioned air adjusted to an appropriate temperature can be blown to an appropriate location in the vehicle interior.

[0062] Next, use Figure 4The electrical control unit of this embodiment is described with reference to the block diagram of FIG. 60. The control device 60 has a well-known microcomputer including a CPU, a ROM, and a RAM, and peripheral circuits. The control device 60 performs various calculations and processes based on the control program stored in the ROM. In addition, the control device 60 controls the operation of various control target devices connected to the output side based on the calculation and processing results.

[0063] A control sensor group including an indoor air temperature sensor 61a, an outdoor air temperature sensor 61b, a sunlight sensor 61c, a high-pressure side refrigerant temperature pressure sensor 62, a low-temperature side cooling water temperature sensor 63, a high-temperature side cooling water temperature sensor 64, and an air conditioning wind temperature sensor 65 is connected to the input side of the control device 60.

[0064] The indoor air temperature sensor 61a is an indoor air temperature detection unit that detects the vehicle interior temperature tr (hereinafter referred to as the indoor air temperature). The outdoor air temperature sensor 61b is an outdoor air temperature detection unit that detects the vehicle exterior temperature Tam (hereinafter referred to as the outdoor air temperature). The sunlight amount sensor 61c is a sunlight amount detection unit that detects the sunlight amount As irradiated into the vehicle interior.

[0065] The high-pressure side refrigerant temperature and pressure sensor 62 is a high-pressure side refrigerant temperature and pressure detection unit that detects the high-pressure side refrigerant temperature T1 and the high-pressure side refrigerant pressure P1 of the refrigerant flowing out of the condenser 15. The low-pressure side cooling water temperature sensor 63 is a low-pressure side heat medium temperature detection unit that detects the low-pressure side cooling water temperature TWL that is the temperature of the cooling water flowing into the cooler core 16.

[0066] The high temperature side coolant temperature sensor 64 is a high temperature side heat medium temperature detection unit that detects a high temperature side coolant temperature TWH which is the temperature of the coolant flowing into the heater core 17 .

[0067] The conditioned air temperature sensor 65 is a conditioned air temperature detection unit that detects the air temperature TAV, which is the temperature of the air blown from the mixing space 56 into the vehicle interior.

[0068] An operation panel 69 is connected to the input side of the control device 60. The operation panel 69 is arranged near the instrument panel in the front part of the vehicle interior, and various operation switches operated by the occupant are provided on the operation panel 69. The control device 60 receives operation signals from the various operation switches.

[0069] Specific examples of the various operation switches provided on the operation panel 69 include an automatic switch, an air conditioning switch, a heating switch, an air volume setting switch, a temperature setting switch, and the like.

[0070] The automatic switch is an automatic control setting unit for setting or releasing the automatic control operation of the vehicle air conditioning device 10. The air conditioning switch is a cooling request unit for requesting the cooler core 16 to cool the air. The heating switch is a heating request unit for requesting the heater core 17 to heat the air. The air volume setting switch is an air volume setting unit for manually setting the air volume of the indoor air blower 52. The temperature setting switch is a temperature setting unit for setting the set temperature Tset in the vehicle interior.

[0071] The control device 60 of this embodiment is integrally constituted with a control unit that controls various control target devices connected to the output side. Therefore, the configuration (hardware and software) that controls the operation of each control target device constitutes a control unit that controls the operation of each control target device.

[0072] Next, the operation of the vehicle air conditioner 10 in the above configuration will be described. The vehicle air conditioner 10 switches between various operation modes to perform air conditioning in the vehicle interior. The operation mode is switched by executing a control program pre-stored in the control device 60 .

[0073] The control program is executed when a start switch of the vehicle system (so-called ignition switch) is turned on and the vehicle system is started.

[0074] In the control program, the detection signal of the sensor group for the above control and the operation signal of the operation panel 69 are read in. Then, the target blowing temperature TAO, which is the target temperature of the air blown into the vehicle interior, is calculated based on the read detection signal and operation signal. Furthermore, the operation mode is selected based on the detection signal, the operation signal, the target blowing temperature TAO, etc., and the operation of various control object devices is controlled according to the selected operation mode.

[0075] Thereafter, the control routine of reading the detection signal and the operation signal, calculating the target air outlet temperature TAO, selecting the operation mode and controlling various control target devices is repeated at every predetermined control cycle until the end condition of the control program is met.

[0076] The target outlet temperature TAO is calculated using the following mathematical formula F1.

[0077] TAO=Kset×Tset-Kr×Tr-Kam×Tam-Ks×As+C...(F1)

[0078] Tset is the set temperature in the vehicle interior set by the temperature setting switch. Tr is the indoor air temperature detected by the indoor air temperature sensor 61a. Tam is the outdoor air temperature detected by the outdoor air temperature sensor 61b. As is the amount of sunlight detected by the sunlight amount sensor 61c. Kset, Kr, Kam, and Ks are control gains, and C is a constant for correction. The following describes each operation mode.

[0079] (a) Cooling mode

[0080] The cooling mode is an operation mode for cooling the vehicle interior by blowing cooled air into the vehicle interior. The cooling mode is selected when the outside air temperature Tam becomes relatively high or the target air outlet temperature TAO becomes relatively low when the automatic switch and the air conditioning switch are turned on.

[0081] In the cooling mode, the control device 60 controls the rotation speed of the compressor 31 so that the temperature TWL of the cooling water at the inlet of the cooler core 16 reaches the target cooling water temperature, and controls the opening of the expansion valve 32 so that the subcooling degree SC1 of the refrigerant that has undergone heat exchange in the condenser 15 becomes the target subcooling degree SCO.

[0082] The control device 60 calculates the target cooler core blowing temperature TCO based on the target blowing temperature TAO, etc. For example, the target cooler core blowing temperature TCO is calculated to decrease as the target blowing temperature TAO decreases.

[0083] For example, the degree of subcooling SC1 of the refrigerant that has undergone heat exchange in the condenser 15 can be calculated based on the high-pressure side refrigerant temperature T1 and the high-pressure side refrigerant pressure P1 detected by the high-pressure side refrigerant temperature and pressure sensor 62. The target degree of subcooling SCO is determined so that the coefficient of performance (so-called COP) of the cycle approaches a maximum value.

[0084] In the cooling mode, the control device 60 controls the flow regulating valve 20 so that the cooling water in the high-temperature cooling water circuit C2 mainly flows to the high-temperature side radiator 19 side, and the cooling water of the flow rate required for heating the air flows to the heater core 17 side. For example, the flow regulating valve 20 is controlled based on the deviation between the air temperature TAV detected by the air conditioning air temperature sensor 65 and the target blowing temperature TAO.

[0085] In the cooling mode, the control device 60 controls the switching valve 18 so that the coolant in the low-temperature coolant circuit C1 flows toward the cooler core 16 .

[0086] The control device 60 controls the rotation speed of the indoor air-sending device 52 based on the target air outlet temperature TAO with reference to a control map pre-stored in the control device 60 .

[0087] The control device 60 adjusts the opening degree of the air mix door 54 so that the air temperature TAV detected by the conditioned air temperature sensor 65 approaches the target air outlet temperature TAO. The control device 60 appropriately controls the operation of other control target devices.

[0088] In the indoor air conditioning unit 50 in the cooling mode, the air blown from the indoor blower 52 is cooled in the cooler core 16. The air cooled by the cooler core 16 is heated again by the heater core 17 according to the opening degree of the air mix door 54. Then, the air whose temperature is adjusted to be close to the target blowing temperature TAO is blown into the vehicle interior, thereby achieving cooling of the vehicle interior.

[0089] (b) Heating mode

[0090] The heating mode is an operation mode for heating the vehicle interior by blowing heated air into the vehicle interior. The heating mode is selected when the outside air temperature Tam becomes relatively low or the target air outlet temperature TAO becomes relatively high when the automatic switch is turned on.

[0091] In the heating mode, the control device 60 controls the rotation speed of the compressor 31 so that the temperature TWH of the cooling water at the inlet of the heater core 17 becomes the target cooling water temperature, and controls the opening of the expansion valve 32 so that the subcooling degree SC1 of the refrigerant subjected to heat exchange in the condenser 15 becomes the target subcooling degree SCO. The target subcooling degree SCO is determined so that the coefficient of performance (so-called COP) of the cycle approaches a maximum value.

[0092] In the heating mode, the control device 60 controls the flow rate regulating valve 20 so that the coolant in the high-temperature coolant circuit C2 flows toward the heater core 17 .

[0093] In the heating mode, the control device 60 controls the switching valve 18 so that the cooling water in the low-temperature cooling water circuit C1 flows toward the low-temperature-side radiator 13 side.

[0094] The control device 60 controls the rotation speed of the indoor air-sending device 52 based on the target air outlet temperature TAO with reference to a control map pre-stored in the control device 60 .

[0095] In the indoor air conditioning unit 50 in the heating mode, the control device 60 controls the rotation speed of the indoor blower 52, the opening degree of the air mix door 54, etc., similarly to the cooling mode. In addition, the control device 60 appropriately controls the operation of other control target devices.

[0096] In the indoor air conditioning unit 50 in the heating mode, the air blown from the indoor blower 52 passes through the cooler core 16. The air that has passed through the cooler core 16 is heated by the heater core 17 according to the opening degree of the air mix door 54. Then, the air whose temperature is adjusted to be close to the target blowing temperature TAO is blown into the vehicle interior, thereby achieving heating of the vehicle interior.

[0097] When the low temperature side pump 11, the high temperature side pump 12 and the compressor 31 are operated, the refrigerant circulates in the refrigeration cycle 30 and the cooling water circulates in the low temperature cooling water circuit C1 and the high temperature cooling water circuit C2.

[0098] In the evaporator 14, the refrigerant of the refrigeration cycle 30 absorbs heat from the cooling water in the low-temperature cooling water circuit C1, so the cooling water in the low-temperature cooling water circuit C1 is cooled. The refrigerant that has absorbed heat in the evaporator 14 dissipates heat to the cooling water in the high-temperature cooling water circuit C2 in the condenser 15. As a result, the cooling water in the high-temperature cooling water circuit C2 is heated.

[0099] The cooling water in the low-temperature cooling water circuit C1 cooled by the evaporator 14 absorbs heat from the outside air in the low-temperature side radiator 13 .

[0100] The coolant in the low-temperature coolant circuit C1 cooled by the evaporator 14 absorbs heat from the air blown by the indoor blower 52 in the cooler core 16. That is, the air blown by the indoor blower 52 is cooled in the cooler core 16.

[0101] Then, the cold air cooled by the cooler core 16 flows into the heater core 17 and the cold air bypass passage 55 according to the opening degree of the air mix door 54 .

[0102] The cold air flowing into the heater core 17 is heated by the coolant in the high-temperature coolant circuit C2 heated by the condenser 15 while passing through the heater core 17 , and is mixed with the cold air passing through the cold air bypass passage 55 in the mixing space 56 .

[0103] Then, the conditioned air whose temperature is adjusted in the mixing space 56 is blown out into the vehicle interior through the opening holes of the air conditioning case 51 .

[0104] When the air temperature inside the vehicle interior becomes lower than the outside air temperature due to the conditioned air blown into the vehicle interior, the vehicle interior is cooled. When the air temperature inside the vehicle interior becomes higher than the outside air temperature due to the conditioned air blown into the vehicle interior, the vehicle interior is heated.

[0105] The refrigerant evaporated by absorbing heat from the cooling water in the low-temperature cooling water circuit C1 in the evaporator 14 is separated into gas and liquid in the accumulator 33. The gas phase refrigerant separated in the accumulator 33 flows into the superheater 34 to exchange heat with the cooling water in the low-temperature cooling water circuit C1.

[0106] The cooling water of the low-temperature cooling water circuit C1 flowing into the superheater 34 is higher in temperature than the refrigerant flowing out of the accumulator 33 . Therefore, the gas-phase refrigerant absorbs heat from the cooling water of the low-temperature cooling water circuit C1 in the superheater 34 and is superheated.

[0107] exist Figure 5 In the Mollier diagram of FIG. 1 , the solid line indicates the state change of the refrigerant in the present embodiment, and the two-dot chain line indicates the state change of the refrigerant in the comparative example. The comparative example is different from the present embodiment in that the superheater 34 is not provided.

[0108] from Figure 5 As can be seen from the Mollier diagram, in the present embodiment, since the gas phase refrigerant is superheated in the superheater 34, the enthalpy difference Δic at low pressure (i.e., the enthalpy difference between the evaporator 14 and the superheater 34) is greater than that in the comparative example. Therefore, the cycle performance (so-called COP) is improved relative to the comparative example.

[0109] In the present embodiment, the superheater 34 is provided for superheating the refrigerant flowing out of the accumulator 33 by exchanging heat with a heat medium having a higher temperature than the refrigerant flowing out of the accumulator 33 .

[0110] According to this, the refrigerant flowing out of the accumulator 33 is superheated in the superheater 34, thereby increasing the enthalpy difference at low pressure, that is, the enthalpy difference between the evaporator 14 and the superheater 34. Therefore, the cycle performance (COP) can be improved.

[0111] In this embodiment, the cooler core 16 is provided for cooling the air by exchanging heat between the cooling water and the air, and the evaporator 14 evaporates the refrigerant decompressed by the expansion valve 32 by exchanging heat with the cooling water. Thus, the refrigerants in the evaporator 14 and the superheater 34 exchange heat with the same heat medium, so the superheater 34 can be easily provided. Therefore, the cycle performance (COP) can be easily improved.

[0112] In the present embodiment, the flow direction of the refrigerant and the flow direction of the cooling water are opposite to each other in the superheater 34 . Thus, the refrigerant can be efficiently superheated in the superheater 34 .

[0113] In this embodiment, the evaporator 14, the superheater 34 and the accumulator 33 are composed of a single heat exchanger unit 35 having a common refrigerant inlet 35a, refrigerant outlet 35b, cooling water inlet 35c and cooling water outlet 35d. Thus, the superheater 34 can be provided with a simple structure.

[0114] (Second Embodiment)

[0115] In this embodiment, if Figure 6 As shown, the vehicle air conditioner 10 includes a bypass flow path 36a and a bypass valve 37 between the evaporator 14 and the superheater 34. The bypass flow path 36a is a refrigerant flow path for the refrigerant flowing out of the evaporator 14 to bypass the accumulator 33 and flow toward the superheater 34. The bypass valve 37 is an electromagnetic valve that opens and closes the bypass flow path 36a.

[0116] like Figure 7 As shown, the bypass flow path 36 a is formed in the bypass forming member 36 . The bypass forming member 36 is a bypass forming portion that forms the bypass flow path 36 a. The bypass forming member 36 is attached to the reservoir 33 .

[0117] An inlet-side flow path 36b and an outlet-side flow path 36c are formed in the bypass forming member 36. The inlet-side flow path 36b is a flow path that guides the refrigerant flowing out of the evaporator 14 to the refrigerant inlet 33a of the accumulator 33. The outlet-side flow path 36c is a flow path that guides the refrigerant flowing out of the refrigerant outlet 33b of the accumulator 33 to the superheater 34.

[0118] The bypass flow path 36a connects the inlet side flow path 36b and the outlet side flow path 36c. The bypass valve 37 is arranged inside the bypass forming member 36. Figure 7 In the figure, the bypass valve 37 is omitted for the convenience of illustration.

[0119] The operation of the bypass valve 37 is controlled by the control device 60. When the bypass valve 37 is closed, the refrigerant flowing out of the evaporator 14 does not flow into the bypass flow path 36a but flows into the accumulator 33. When the bypass valve 37 is open, the refrigerant flowing out of the evaporator 14 flows into the bypass flow path 36a and the accumulator 33 in parallel.

[0120] When the bypass valve 37 is open, the refrigerant flow rate ratio between the bypass flow path 36 a and the accumulator 33 is, for example, 1:1.

[0121] For example, the control device 60 opens the bypass valve 37 when the discharge flow rate of the compressor 31 (in other words, the refrigerant discharge capacity) exceeds the specified flow rate (in other words, the specified capacity), and closes the bypass valve 37 when the discharge flow rate of the compressor 31 is lower than the specified value.

[0122] Thus, when the flow rate of the refrigerant circulating in the refrigeration cycle 30 is high, the flow of the refrigerant to the accumulator 33 can be cut off to reduce the refrigerant pressure loss and improve the cycle performance (COP). On the other hand, when the flow rate of the refrigerant circulating in the refrigeration cycle 30 is low, the flow of the refrigerant to the bypass flow path 36a can be cut off to allow the refrigerant to flow into the accumulator 33 reliably.

[0123] In the second embodiment, the bypass valve 37 is not necessarily provided, and the refrigerant flowing out of the evaporator 14 may always flow in parallel to the bypass flow path 36 a and the accumulator 33 without providing the bypass valve 37 .

[0124] (Third Embodiment)

[0125] In the above embodiment, the superheater 34 is a heat exchanger that superheats the gas phase refrigerant flowing out of the accumulator 33 by exchanging heat with cooling water. However, in the present embodiment, Figure 8 As shown, the superheater 34 is a heat exchanger that superheats the gas phase refrigerant flowing out of the accumulator 33 by exchanging heat with the high-pressure side refrigerant flowing out of the condenser 15 (that is, refrigerant with a higher temperature than the refrigerant flowing out of the accumulator 33).

[0126] In the present embodiment, as in the above-described embodiment, the refrigerant flowing out of the accumulator 33 is superheated in the superheater 34 , thereby making it possible to improve the cycle performance COP.

[0127] The present disclosure is not limited to the above-described embodiments, and various modifications as described below are possible within the scope not departing from the spirit of the present disclosure.

[0128] The above-mentioned embodiments can be combined as appropriate. For example, the above-mentioned embodiments can be variously modified as follows.

[0129] In the above embodiment, cooling water is used as the heat medium flowing in the low-temperature cooling water circuit C1 and the high-temperature cooling water circuit C2, but various media such as oil can also be used as the heat medium. As the heat medium, ethylene glycol antifreeze, water, or air maintained at a certain temperature or above can also be used. As the heat medium, nanofluid can also be used. Nanofluid refers to a fluid mixed with nanoparticles with a particle size of nanometers.

[0130] In the refrigeration cycle 30 of the above embodiment, a freon-based refrigerant is used as the refrigerant, but the type of the refrigerant is not limited thereto, and a natural refrigerant such as carbon dioxide, a hydrocarbon-based refrigerant, or the like may be used.

[0131] The refrigeration cycle 30 of the above embodiment constitutes a subcritical refrigeration cycle in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant, but may constitute a supercritical refrigeration cycle in which the high-pressure side refrigerant pressure exceeds the critical pressure of the refrigerant.

[0132] In the above embodiment, an example of applying the vehicle air conditioner 10 to an electric vehicle is shown, but the vehicle air conditioner 10 may also be applied to a hybrid vehicle that obtains a driving force for the vehicle from an engine (internal combustion engine) and a driving electric motor. For example, a hybrid vehicle may also be configured as a plug-in hybrid vehicle that can charge a battery mounted on the vehicle with power supplied from an external power source when the vehicle is parked.

[0133] In the above embodiment, the refrigeration cycle 30 is used in the vehicle air conditioning device 10 for adjusting the vehicle interior space to an appropriate temperature, but the refrigeration cycle 30 may be used in a vehicle equipment temperature adjustment device for adjusting various vehicle equipment to an appropriate temperature.

[0134] For example, the refrigeration cycle 30 may be used in a vehicle battery temperature control device for controlling the vehicle battery to an appropriate temperature. Specifically, the vehicle battery, the evaporator 14, the condenser 15, the cooler core 16, the heater core 17, etc. may be arranged in the battery unit box.

[0135] The refrigeration cycle 30 can be used not only for in-vehicle equipment but also for an equipment temperature adjustment device for adjusting various equipment (for example, non-in-vehicle equipment) to an appropriate temperature.

[0136] The present disclosure is described based on the embodiments, but it should be understood that the present disclosure is not limited to the embodiments and structures. The present disclosure also includes various modifications and variations within the equivalent range. In addition, various combinations and methods, and even other combinations and methods that only include one element, more than one element, or less than one element, are also included in the scope and thought range of the present disclosure.

[0137] The features of the refrigeration cycle device disclosed in this specification are as follows.

[0138] (Item 1)

[0139] A refrigeration cycle device, comprising:

[0140] A compressor (31) that sucks in, compresses, and discharges a refrigerant;

[0141] a radiator (15) for dissipating heat from the refrigerant discharged from the compressor;

[0142] a decompression section (32) for decompressing the refrigerant after heat is released by the radiator;

[0143] an evaporation section (14) for evaporating the refrigerant decompressed by the decompression section;

[0144] A liquid accumulator (33) that separates the refrigerant evaporated in the evaporation section into gas and liquid and allows the refrigerant in a gas phase to flow out; and

[0145] A superheating unit (34) is configured to superheat the refrigerant flowing out of the accumulator by exchanging heat with a heat medium having a higher temperature than the refrigerant flowing out of the accumulator.

[0146] (Item 2)

[0147] The refrigeration cycle device according to item 1, wherein:

[0148] A cooling heat exchanger (16) is provided, which cools the cooling object by exchanging heat between the heat medium and the cooling object.

[0149] The evaporation unit evaporates the refrigerant decompressed by the decompression unit by exchanging heat with the heat medium.

[0150] (Item 3)

[0151] The refrigeration cycle device according to item 1 or 2, wherein, in the superheating section, a flow direction of the refrigerant and a flow direction of the heat medium are opposite to each other.

[0152] (Item 4)

[0153] A refrigeration cycle device according to any one of items 1 to 3, wherein the evaporation section, the superheating section and the liquid accumulator are composed of a single heat exchanger unit (35) having a common refrigerant inlet (35a), a refrigerant outlet (35b), a heat medium inlet (35c) and a heat medium outlet (35d).

[0154] (Item 5)

[0155] The refrigeration cycle device according to any one of items 1 to 4, comprising:

[0156] a bypass forming portion (36) forming a bypass flow path (36a) for allowing the refrigerant evaporated in the evaporation portion to flow around the accumulator;

[0157] a bypass valve (37) for opening and closing the bypass flow path; and

[0158] A control unit (60) opens the bypass valve when the refrigerant discharge capacity of the compressor exceeds a predetermined capacity, and closes the bypass valve when the refrigerant discharge capacity of the compressor falls below the predetermined capacity.

Claims

1. A refrigeration cycle device, characterized in that: have: A compressor (31) that sucks in, compresses, and discharges a refrigerant; a radiator (15) for dissipating heat from the refrigerant discharged from the compressor; a decompression section (32) for decompressing the refrigerant after heat is released by the radiator; an evaporation section (14) for evaporating the refrigerant decompressed by the decompression section; A liquid accumulator (33) that separates the refrigerant evaporated in the evaporation section into gas and liquid and allows the refrigerant in a gas phase to flow out; as well as A superheating unit (34) is configured to superheat the refrigerant flowing out of the accumulator by exchanging heat with a heat medium having a higher temperature than the refrigerant flowing out of the accumulator.

2. The refrigeration cycle device according to claim 1, characterized in that: A cooling heat exchanger (16) is provided, which cools the cooling object by exchanging heat between the heat medium and the cooling object. The evaporation unit evaporates the refrigerant decompressed by the decompression unit by exchanging heat with the heat medium.

3. The refrigeration cycle device according to claim 1, characterized in that: In the superheating section, a flow direction of the refrigerant and a flow direction of the heat medium are opposite to each other.

4. The refrigeration cycle device according to claim 1, characterized in that: The evaporation part, the superheating part and the accumulator are composed of a single heat exchanger unit (35) having a common refrigerant inlet (35a), a refrigerant outlet (35b), a heat medium inlet (35c) and a heat medium outlet (35d).

5. The refrigeration cycle device according to any one of claims 1 to 4, characterized in that: have: a bypass forming portion (36) forming a bypass flow path (36a) for allowing the refrigerant evaporated in the evaporation portion to flow around the accumulator; a bypass valve (37) for opening and closing the bypass flow path; and A control unit (60) opens the bypass valve when the refrigerant discharge capacity of the compressor exceeds a predetermined capacity, and closes the bypass valve when the refrigerant discharge capacity of the compressor falls below the predetermined capacity.

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