JP2013203221A - Air conditioner for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner for a vehicle which prevents an odor or frost on a window while achieving both of defrosting and heating capacity.SOLUTION: An air conditioner for a vehicle is comprises a refrigeration cycle device provided with a main refrigeration circuit which sequentially keeps a compressor, an indoor condenser, a first variable throttle, an outdoor heat exchanger and a compressor to circulate a refrigerant, and an indoor air conditioning unit containing at least a blower for blowing in-cabin blowing air and an indoor condenser for heating the in-cabin blowing air, wherein the indoor condenser allows hot gas defrosting while performing hot gas heating in a cabin by melting deposited frost through the heating of the in-cabin blowing air and the heat radiation of the outdoor heat exchanger.

Description

  TECHNICAL FIELD The present invention relates to an air conditioner for a vehicle that does not cause window fogging or bad odor while achieving both defrosting of an outdoor heat exchanger and heating capability. It is mainly suitable for an air conditioner for a vehicle that lacks a heat source for heating, such as a vehicle that does not have a combustion engine, such as an electric vehicle or a hybrid car, or a vehicle that does not operate a combustion engine.

  2. Description of the Related Art In recent years, an electric vehicle that has been widely used does not include an engine (internal combustion engine) that outputs driving force for traveling, and therefore cannot use waste heat of the engine as a heat source when heating the passenger compartment. . Therefore, as a vehicle air conditioner applied to an electric vehicle, an air conditioner that heats a vehicle interior using a high-temperature and high-pressure refrigerant discharged from an electric compressor of a heat pump cycle (vapor compression refrigeration cycle) as a heat source is known. Yes.

  Patent Document 1 discloses an air conditioning system using a gas injection heat pump technology as an air conditioning system for an electric vehicle. Regarding a defrosting technique which is a problem of the heat pump technology, a vehicle while defrosting an outdoor heat exchanger is disclosed. Systems that can also be used for indoor heating have been proposed. In this system, during defrosting, the air passage to the indoor condenser is fully closed by the mix door, and the discharged gas refrigerant (hot gas) from the compressor is not exchanged in the HVAC without exchanging heat by the indoor condenser. It is introduced into the indoor evaporator. The indoor evaporator functions as a cooler in the cooling and dehumidifying modes, but is used as an air heater for heating the vehicle interior when the outdoor heat exchanger is defrosted.

  For this reason, if the indoor evaporator retains water after dehumidifying operation etc. before defrosting, the water that has been retained evaporates as soon as the hot gas refrigerant flows into the indoor evaporator. It will be blown out into the passenger compartment. Such steam blowing can be recondensed on the windshield and cause window fogging. In addition, there is a concern that an odor component may be blown out together with steam to cause a bad odor. Furthermore, in this system, the vehicle interior may not be sufficiently heated due to insufficient heating performance.

JP 2001-30744 A

  In view of the possibility of the above problem, the present invention achieves both the defrosting of the outdoor heat exchanger and the heating capacity by a system that also performs hot gas heating while defrosting the hot heat of the outdoor heat exchanger. The present invention provides an air conditioner for a vehicle that does not cause fogging or odor. Hot gas heating and hot gas defrosting are heat exchange cycles performed using sensible heat of a high-temperature gas refrigerant from a compressor.

  In order to solve the above problems, the invention of claim 1 includes a compressor (11), an indoor condenser (12), a first variable throttle (13), an outdoor heat exchanger (20), and the compressor (11). A refrigeration cycle apparatus having a main refrigerant circuit in which the refrigerant circulates, at least a blower (32) for blowing the air blown into the vehicle interior, and the indoor condenser (12) for heating the air blown into the vehicle compartment An air conditioner for a vehicle having an indoor air conditioning unit (30) having the indoor condenser (12) heats the air blown into the vehicle interior and the outdoor heat exchanger (20) dissipates heat. This is an air conditioner for a vehicle that can defrost hot gas while heating the interior of the vehicle by melting frosted ice.

  In addition, the code | symbol attached | subjected above is an example which shows a corresponding relationship with the specific embodiment as described in embodiment mentioned later.

It is a whole block diagram which shows the refrigerant | coolant flow path at the time of the 1st heating mode of 1st Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant at the time of the 1st heating mode of 1st Embodiment. It is a whole block diagram which shows the refrigerant | coolant flow path at the time of the 2nd heating mode of 1st Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant at the time of the 2nd heating mode of 1st Embodiment. It is explanatory drawing in the Mollier diagram in the case of switching from heating mode to defrost heating mode. It is a whole block diagram which shows the refrigerant | coolant flow path at the time of the cooling operation mode / dehumidification heating operation mode of 1st Embodiment. It is a Mollier diagram which shows the refrigerant | coolant state at the time of the air_conditionaing | cooling operation mode of 1st Embodiment. It is a Mollier diagram which shows the refrigerant | coolant state at the time of the 1st dehumidification heating operation mode of 1st Embodiment. It is a Mollier diagram which shows the refrigerant | coolant state at the time of the 2nd dehumidification heating operation mode of 1st Embodiment. It is a Mollier diagram which shows the refrigerant | coolant state at the time of the 3rd dehumidification heating operation mode of 1st Embodiment. It is a Mollier diagram which shows the refrigerant | coolant state at the time of the 4th dehumidification heating operation mode of 1st Embodiment. It is a Mollier diagram explaining the refrigerant | coolant state at the time of the 2nd dehumidification heating operation mode of 1st Embodiment. It is a Mollier diagram explaining the refrigerant | coolant state at the time of the 3rd dehumidification heating operation mode of 1st Embodiment. It is a whole block diagram which shows the refrigerant | coolant flow path at the time of the 1st, 2nd heating mode of 2nd Embodiment. It is a whole block diagram of 3rd Embodiment. It is explanatory drawing explaining the action | operation of the intermediate pressure side on-off valve of 4th Embodiment. It is a whole block diagram which shows the refrigerant | coolant flow path at the time of the cooling operation mode of the heat pump cycle of 4th Embodiment. It is a whole block diagram which shows the refrigerant | coolant flow path at the time of the heating operation mode of the heat pump cycle of 4th Embodiment.

First, the overall operation mode of the first embodiment of the present invention will be described with reference to FIGS. Of these, the defrosting heating mode described later constitutes a feature of the present invention.
In the present embodiment, the heat pump cycle 10 is applied to a vehicle air conditioner 1 for an electric vehicle that obtains a driving force for vehicle traveling from a traveling electric motor. The heat pump cycle 10 functions in the vehicle air conditioner 1 to cool or heat the vehicle interior air blown into the vehicle interior that is the air-conditioning target space.

  Therefore, the heat pump cycle 10 according to the present embodiment includes a refrigerant in a cooling operation mode for cooling the vehicle interior or a dehumidification heating operation mode (dehumidification operation mode) for heating while dehumidifying the vehicle interior, as shown in the overall configuration diagram of FIG. 4A. As shown in the entire configuration diagram of the circuit and FIGS. 1A and 2A, the refrigerant circuit in the heating operation mode for heating the vehicle interior can be switched.

  Furthermore, in this heat pump cycle 10, as will be described later, as a heating operation mode, the first heating mode (FIG. 1A) executed when the outside air temperature is low (for example, including 0 ° C. or less), normal heating is performed. The second heating mode to be executed (FIG. 2A) can be executed. In FIGS. 1A, 2A, and 4A, the refrigerant flow in each operation mode is indicated by solid arrows.

  The heat pump cycle 10 employs an HFC refrigerant (specifically, R134a) as the refrigerant, and constitutes a vapor compression subcritical refrigeration cycle in which the high-pressure side refrigerant pressure does not exceed the critical pressure of the refrigerant. Yes. Of course, you may employ | adopt HFO type refrigerant | coolants (for example, R1234yf). This refrigerant is mixed with refrigerating machine oil for lubricating the compressor 11, and a part of the refrigerating machine oil circulates in the cycle together with the refrigerant.

  In addition, about the amount of refrigerant | coolants enclosed, it is the quantity which added the predetermined surplus amount with respect to the maximum circulation flow rate which needs to circulate a cycle at the time of the high load driving | running which makes the heat pump cycle 10 exhibit the maximum refrigerating capacity. . This surplus amount is determined in consideration of the fact that the refrigerant sealed in the cycle due to aging leaks to the outside through a rubber hose or other connection part that connects each component of the heat pump cycle 10. Yes.

  Among the components of the heat pump cycle 10, the compressor 11 is disposed in the hood of the vehicle, and sucks, compresses and discharges the refrigerant in the heat pump cycle 10. The compressor 11 includes two compression mechanisms, a low-stage compression mechanism and a high-stage compression mechanism, each of which is a fixed-capacity compression mechanism, and both of the compression mechanisms. This is a two-stage boosting type electric compressor configured to accommodate an electric motor that is driven to rotate.

  A suction port 11a that sucks low-pressure refrigerant from the outside of the housing into the low-stage compression mechanism, and an intermediate pressure where intermediate-pressure refrigerant flows from the outside of the housing into the housing and merges with the refrigerant in the compression process. A pressure port 11b and a discharge port 11c for discharging the high-pressure refrigerant discharged from the high-stage compression mechanism to the outside of the housing are provided.

  More specifically, the intermediate pressure port 11b is connected to the refrigerant discharge port side of the low-stage compression mechanism (that is, the refrigerant suction port side of the high-stage compression mechanism). Various types such as a scroll type compression mechanism, a vane type compression mechanism, and a rolling piston type compression mechanism can be adopted as the low stage side compression mechanism and the high stage side compressor.

  The operation (rotation speed) of the electric motor is controlled by a control signal output from the air conditioning control device 40 described later, and either an AC motor or a DC motor may be adopted. And the refrigerant | coolant discharge capability of the compressor 11 is changed by this rotation speed control. Therefore, in this embodiment, the electric motor constitutes the discharge capacity changing means of the compressor 11.

  In addition, in this embodiment, although the compressor 11 which accommodated two compression mechanisms in one housing is employ | adopted, the format of a compressor is not limited to this. In other words, if the intermediate pressure refrigerant can be introduced from the intermediate pressure port 11b and merged with the refrigerant in the compression process, one fixed capacity type compression mechanism and an electric motor that rotationally drives the compression mechanism are provided inside the housing. An electric compressor configured to house a motor may be used. The embodiment includes a case where the intermediate pressure refrigerant is not introduced.

  The refrigerant inlet side of the indoor condenser 12 is connected to the discharge port 11 c of the compressor 11. The indoor condenser 12 is disposed in an air conditioning case 31 of an indoor air conditioning unit 30 of the vehicle air conditioner 1 to be described later, and dissipates high-pressure refrigerant discharged from the compressor 11 (specifically, a high-stage compression mechanism). It is a radiator that heats the air blown into the passenger compartment that has passed through the indoor evaporator 23 described later.

  The refrigerant outlet side of the indoor condenser 12 is connected to the inlet side of the first variable throttle 13 that can depressurize the high-pressure refrigerant flowing out of the indoor condenser 12 until it becomes an intermediate-pressure refrigerant. The first variable throttle 13 is an electric variable variable valve that is configured to change the throttle opening and an electric actuator including a stepping motor that changes the throttle opening of the valve. An aperture mechanism.

  The first variable throttle 13 is configured to be able to be set to a throttle state that exerts a pressure reducing action and a fully open state that does not exert a pressure reducing action. More specifically, in the first variable throttle 13, when the refrigerant is depressurized, the throttle opening is changed in a range in which the throttle passage area has an equivalent diameter of φ0.5 to φ3 mm. Furthermore, when the throttle opening is fully opened, the throttle passage area can be ensured to have an equivalent diameter of about 10 mm so that the refrigerant decompression action is not exhibited. Further, the refrigerant flow path from the outdoor heat exchanger 20 to the indoor evaporator 23 can be closed by closing the throttle opening. The operation of the first variable aperture 13 is controlled by a control signal output from the air conditioning control device 40.

  On the outlet side of the first variable throttle 13, there is a gas-liquid separator 14 as a gas-liquid separator that separates the gas-liquid of the intermediate pressure refrigerant that flows out of the indoor condenser 12 and is decompressed by the first variable throttle 13. A refrigerant inflow port 14b is connected. This gas-liquid separator 14 is of a centrifugal separation type that separates the gas-liquid of the refrigerant by the action of centrifugal force (see JP 2009-174836 A).

  The gas-liquid separator 14 according to the present embodiment includes a refrigerant inlet port 14b in which a refrigerant inlet for allowing intermediate pressure refrigerant to flow in is formed, and a gas phase refrigerant in which a gas-phase refrigerant outlet for discharging separated vapor refrigerant is formed. It has an outflow port 14c and a liquid phase refrigerant outflow port 14d in which a liquid phase refrigerant outlet for allowing the separated liquid phase refrigerant to flow out is formed (see FIG. 1A). Normally, the liquid phase refrigerant flows out from the liquid phase refrigerant outflow port 14d, but in the case of the defrost heating mode described later, the gas phase refrigerant may flow out.

  An intermediate pressure port 11 b of the compressor 11 is connected to the gas-phase refrigerant outlet port 14 c of the gas-liquid separator 14 through an intermediate pressure refrigerant passage 15. An intermediate pressure side opening / closing valve 16 a is disposed in the intermediate pressure refrigerant passage 15. The intermediate pressure side opening / closing valve 16 a is an electromagnetic valve that opens and closes the intermediate pressure refrigerant passage 15, and its operation is controlled by a control signal output from the air conditioning control device 40.

  The intermediate pressure side opening / closing valve 16a is a check that allows only the refrigerant to flow from the gas phase refrigerant outlet of the gas-liquid separator 14 to the intermediate pressure port 11b side of the compressor 11 when the intermediate pressure refrigerant passage 15 is opened. It also functions as a valve. This prevents the refrigerant from flowing back from the compressor 11 side to the gas-liquid separator 14 when the intermediate pressure side opening / closing valve 16a opens the intermediate pressure refrigerant passage 15.

  Further, the intermediate pressure side opening / closing valve 16 a functions to switch the cycle configuration (refrigerant flow path) by opening and closing the intermediate pressure refrigerant passage 15. Therefore, the intermediate pressure side opening / closing valve 16a of the present embodiment constitutes a refrigerant flow path switching means for switching the refrigerant flow path of the refrigerant circulating in the cycle.

  The intermediate pressure side on-off valve 16a of the present embodiment is configured to open and close the intermediate pressure refrigerant passage 15 in conjunction with the state (throttle state, fully open state) of the low stage side pressure reducing means. The low stage pressure reducing means refers to a combination of the second variable throttle 17 and the low pressure side on-off valve 16b inserted in parallel therewith.

  Specifically, the intermediate pressure side on / off valve 16a opens the intermediate pressure refrigerant passage 15 when the low pressure side on / off valve 16b of the low stage side pressure reducing means is closed and the entire low stage side pressure reducing means is in the throttle state. It is configured. The intermediate pressure side on / off valve 16a is configured to close the intermediate pressure refrigerant passage 15 when the low pressure side on / off valve 16b of the low stage side pressure reducing means is opened and the entire low stage side pressure reducing means is fully opened. Yes.

  On the other hand, the liquid-phase refrigerant outflow port 14d of the gas-liquid separator 14 is connected to the inlet side of the low-stage decompression means capable of decompressing the liquid-phase refrigerant flowing out of the gas-liquid separator 14, and the outlet of the low-stage decompression means The refrigerant inlet side of the outdoor heat exchanger 20 is connected to the side.

  The low-stage depressurization means of the present embodiment includes a second variable throttle 17 that depressurizes the liquid-phase refrigerant separated by the gas-liquid separator 14 until it becomes a low-pressure refrigerant, and the liquid phase separated by the gas-liquid separator 14. The bypass passage 18 guides refrigerant to the outdoor heat exchanger 20 side by bypassing the second variable throttle 17, and the low-pressure side opening / closing valve 16b as a passage opening / closing valve for opening and closing the bypass passage 18. The basic configuration of the low pressure side on / off valve 16b is the same as that of the intermediate pressure side on / off valve 16a, and is an electromagnetic valve whose opening / closing operation is controlled by a control voltage output from the air conditioning control device 40.

  Here, the pressure loss that occurs when the refrigerant passes through the low-pressure side opening / closing valve 16 b is extremely smaller than the pressure loss that occurs when the refrigerant passes through the second variable throttle 17. Therefore, the refrigerant flowing out of the indoor condenser 12 flows into the outdoor heat exchanger 20 via the bypass passage 18 when the low-pressure side opening / closing valve 16b is open, and the low-pressure side opening / closing valve 16b is closed. In this case, the refrigerant flows into the outdoor heat exchanger 20 through the second variable throttle 17.

  As a result, the low-stage pressure reducing means can be changed between a throttled state that exerts a pressure reducing action and a fully open state that does not exert a pressure reducing action by opening and closing the low pressure side opening / closing valve 16b. The low-pressure side opening / closing valve 16b is connected to the outlet side of the liquid-phase refrigerant outlet port 14d of the gas-liquid separator 14 and the inlet side of the second variable throttle 17 and the outlet side of the outlet of the liquid-phase refrigerant outlet port 14d and the bypass passage. An electric three-way valve or the like that switches the refrigerant circuit connecting the 18 inlet side may be adopted.

  The second variable throttle 17 can be used as a fixed throttle in a state where the throttle opening is fixed. In this case, since the throttle passage area is suddenly reduced or expanded rapidly, the flow rate of the refrigerant passing through the fixed throttle and the second variable throttle as the pressure difference between the upstream side and the downstream side (differential pressure between the inlet and outlet) changes. 17 The dryness X of the upstream refrigerant can be self-adjusted (balanced).

  Specifically, when the pressure difference is relatively large, a balance is made so that the dryness of the fixed throttle upstream side refrigerant increases as the necessary circulating refrigerant flow rate required to circulate the cycle decreases. On the other hand, when the pressure difference is relatively small, it is balanced so that the dryness of the fixed throttle upstream side refrigerant decreases as the required circulating refrigerant flow rate increases.

  However, if the degree of dryness of the refrigerant upstream of the second variable throttle 17 increases, the refrigerant heat absorption in the outdoor heat exchanger 20 occurs when the outdoor heat exchanger 20 functions as an evaporator that exerts an endothermic effect on the refrigerant. The amount of heat (refrigeration capacity) decreases and the coefficient of performance (COP) of the cycle deteriorates.

  Therefore, in this embodiment, the opening degree is controlled so that the dryness X of the refrigerant upstream of the second variable throttle 17 is 0.1 or less even if the required circulating refrigerant flow rate changes due to the cycle load fluctuation in the heating operation mode. In addition, the deterioration of COP is suppressed.

  That is, in the second variable throttle 17 of the present embodiment, even if the refrigerant circulation flow rate Q and the differential pressure between the inlet and outlet of the second variable throttle 17 change within a range that is assumed when a load fluctuation occurs in the heat pump cycle 10. The dryness X of the refrigerant upstream of the second variable throttle 17 is adjusted to 0.1 or less.

  The outdoor heat exchanger 20 is disposed in the hood, and exchanges heat between the low-pressure refrigerant circulating inside and the outside air blown from the blower fan 21. The outdoor heat exchanger 20 functions as an evaporator that evaporates the low-pressure refrigerant and exerts an endothermic effect in the first and second heating modes, and dissipates the high-pressure refrigerant in the cooling operation mode and the like. It is a heat exchanger that functions as a radiator.

  The refrigerant inlet side of the third variable throttle 22 is connected to the refrigerant outlet side of the outdoor heat exchanger 20. The third variable throttle 22 is for depressurizing the refrigerant that has flowed out of the outdoor heat exchanger 20 in the cooling operation mode or the like, and depressurizing the refrigerant that flows into the indoor evaporator 23. The basic configuration of the third variable aperture 22 is the same as that of the first variable aperture 13, and its operation is controlled by a control signal output from the air conditioning control device 40.

  The refrigerant inlet side of the indoor evaporator 23 is connected to the outlet side of the third variable throttle 22. The indoor evaporator 23 is disposed in the air conditioning case 31 of the indoor air conditioning unit 30 on the upstream side of the air flow in the vehicle interior of the indoor condenser 12 and circulates in the dehumidifying and heating operation mode or the like in the cooling operation mode. It is an evaporator that cools the air blown into the passenger compartment by evaporating the refrigerant and exerting an endothermic effect.

  The outlet side of the indoor evaporator 23 is connected to the inlet side of the accumulator 24. The accumulator 24 is a low-pressure side gas-liquid separator that separates the gas-liquid refrigerant flowing into the accumulator 24 and stores excess refrigerant. Furthermore, the suction port 11 a of the compressor 11 is connected to the gas phase refrigerant outlet of the accumulator 24. Therefore, the indoor evaporator 23 is connected so as to flow out to the suction port 11 a side of the compressor 11.

  Further, on the refrigerant outlet side of the outdoor heat exchanger 20, there is a bypass passage 25 that guides the refrigerant flowing out of the outdoor heat exchanger 20 to the inlet side of the accumulator 24 by bypassing the third variable throttle 22 and the indoor evaporator 23. It is connected. In the bypass passage 25, a cooling on-off valve 16c for opening and closing the bypass passage 25 is disposed.

  The basic configuration of the cooling on-off valve 16c is the same as that of the intermediate pressure side on-off valve 16a, and is an electromagnetic valve whose opening / closing operation is controlled by a control voltage output from the air conditioning control device 40. Further, the pressure loss that occurs when the refrigerant passes through the cooling on-off valve 16 c is extremely small compared to the pressure loss that occurs when the refrigerant passes through the third variable throttle 22.

  Therefore, the refrigerant that has flowed out of the outdoor heat exchanger 20 flows into the accumulator 24 through the bypass passage 25 when the cooling on-off valve 16c is open. At this time, the opening degree of the third variable throttle 22 may be fully closed. Further, when the cooling on-off valve 16 c is closed, it flows into the indoor evaporator 23 through the third variable throttle 22. Thereby, the cooling on-off valve 16c can switch the refrigerant flow path of the heat pump cycle 10. Therefore, the cooling on-off valve 16c of the present embodiment constitutes a refrigerant flow switching means together with the intermediate pressure side on-off valve 16a.

  Next, the indoor air conditioning unit 30 will be described. The indoor air conditioning unit 30 is arranged inside the instrument panel (instrument panel) at the foremost part of the vehicle interior, forms an outer shell of the indoor air conditioning unit 30, and is blown into the vehicle interior in the vehicle interior. The air-conditioning case 31 that forms the air passage is provided. And the air blower 32, the indoor condenser 12, the indoor evaporator 23, etc. are accommodated in this air passage.

  On the most upstream side of the air flow in the air conditioning case 31, an inside / outside air switching device 33 that switches and introduces vehicle interior air (inside air) and outside air is disposed. The inside / outside air switching device 33 continuously adjusts the opening area of the inside air introduction port for introducing the inside air into the air conditioning case 31 and the outside air introduction port for introducing the outside air by the inside / outside air switching door, so that the air volume of the inside air and the outside air are adjusted. The air volume ratio with the air volume is continuously changed.

  On the downstream side of the air flow of the inside / outside air switching device 33, a blower 32 that blows air sucked through the inside / outside air switching device 33 toward the vehicle interior is arranged. The blower 32 is an electric blower that drives a centrifugal multiblade fan (sirocco fan) with an electric motor, and the number of rotations (air flow rate) is controlled by a control voltage output from the air conditioning control device 40.

  On the downstream side of the air flow of the blower 32, the indoor evaporator 23 and the indoor condenser 12 described above are arranged in the order of the indoor evaporator 23 → the indoor condenser 12 with respect to the flow of the air blown into the vehicle interior. In other words, the indoor evaporator 23 is disposed on the upstream side of the air flow with respect to the indoor condenser 12.

  Further, a bypass passage 35 is provided in the air conditioning case 31 to flow the blown air after passing through the indoor evaporator 23, bypassing the indoor condenser 12, on the downstream side of the air flow of the indoor evaporator 23. And the air mix door 34 is arrange | positioned in the air flow upstream of the indoor condenser 12. FIG.

  The air mix door 34 adjusts the air volume ratio between the air volume that passes through the indoor condenser 12 and the air volume that passes through the bypass passage 35 in the blown air that has passed through the indoor evaporator 23, and the heat of the indoor condenser 12. It is a heat exchange capacity adjustment means for adjusting the exchange capacity. The air mix door 34 is driven by a servo motor (not shown) whose operation is controlled by a control signal output from the air conditioning controller 40.

  Further, on the downstream side of the air flow of the indoor condenser 12 and the bypass passage 35, the vehicle interior blown air heated by exchanging heat with the refrigerant in the indoor condenser 12 and the vehicle that has not passed through the bypass passage 35 and is not heated. A merging space 36 in which the indoor blast air merges is provided.

  An opening hole is provided in the most downstream portion of the air flow case of the air conditioning case 31 to blow out the blown air that has merged in the merge space 36 into the vehicle interior that is the space to be cooled. Specifically, as this opening hole, a defroster opening hole 37a that blows conditioned air toward the inner side surface of the vehicle front window glass, a face opening hole 37b that blows conditioned air toward the upper body of the passenger in the passenger compartment, and the feet of the passenger The foot opening hole 37c which blows air-conditioning wind toward is provided.

  Therefore, the temperature of the blast air in the merge space 36 is adjusted by adjusting the air volume ratio between the air volume that allows the air mix door 34 to pass through the indoor condenser 12 and the air volume that passes through the bypass passage. The air mix door 34 is driven by a servo motor (not shown) whose operation is controlled by a control signal output from the air conditioning controller 40.

  Further, on the upstream side of the air flow of the defroster opening hole 37a, the face opening hole 37b, and the foot opening hole 37c, the opening areas of the defroster door 38a and the face opening hole 37b for adjusting the opening area of the defroster opening hole 37a are adjusted. A foot door 38c for adjusting the opening area of the face door 38b and the foot opening hole 37c is disposed.

  The defroster door 38a, the face door 38b, and the foot door 38c constitute an opening hole mode switching unit that switches the opening hole mode. The defroster door 38a, the face door 38b, and the foot door 38c are controlled by a control signal output from the air conditioning controller 40 via a link mechanism or the like. It is driven by a servo motor (not shown) whose operation is controlled.

  In addition, the air flow downstream side of the defroster opening hole 37a, the face opening hole 37b, and the foot opening hole 37c is respectively connected to a face air outlet, a foot air outlet, and a defroster air outlet provided in the vehicle interior via ducts that form air passages. Connected to the exit.

  Next, the electric control unit of this embodiment will be described. The air conditioning control device 40 is composed of a well-known microcomputer including a CPU, ROM, RAM, etc. and its peripheral circuits, and performs various calculations and processing based on an air conditioning control program stored in the ROM, and is connected to the output side. The operation of the various air conditioning control devices (the compressor 11, the first to third variable throttles, the low pressure side opening / closing valve 16b of the low stage side pressure reducing means, the refrigerant flow switching means 16a, 16c, the blower 32, etc.) is controlled.

  Further, on the input side of the air-conditioning control device 40, there are an inside air sensor that detects the temperature in the vehicle interior, an outside air sensor 41-1 that detects the outside air temperature Tam, a solar radiation sensor that detects the amount of solar radiation in the vehicle interior, and the indoor evaporator 23. An evaporator temperature sensor for detecting the blown air temperature (evaporator temperature), a discharge pressure sensor for detecting the high-pressure refrigerant pressure discharged from the compressor 11, a suction pressure sensor for detecting the suction refrigerant pressure sucked into the compressor 11, Various air-conditioning control sensor groups 41 such as an outlet refrigerant temperature sensor 41-2 of the outdoor heat exchanger 20 are connected. The outlet refrigerant temperature sensor 41-2 detects the outlet refrigerant temperature Tho of the outdoor heat exchanger 20.

  Furthermore, an operation panel (not shown) disposed near the instrument panel in the front of the passenger compartment is connected to the input side of the air conditioning control device 40, and operation signals from various air conditioning operation switches provided on the operation panel are input. The Specifically, various air conditioning operation switches provided on the operation panel include an operation switch of the vehicle air conditioner 1, a vehicle interior temperature setting switch for setting the vehicle interior temperature, a selection switch between the cooling operation mode and the heating operation mode, and the like. Is provided.

  The air-conditioning control device 40 is configured integrally with control means for controlling the operation of various air-conditioning control devices connected to the output side, but the configuration (hardware) for controlling the operation of each control target device. Hardware and software) constitutes control means for controlling the operation of each control target device.

  For example, in the present embodiment, the configuration (hardware and software) that controls the operation of the electric motor of the compressor 11 constitutes the discharge capacity control means, and the configuration (hardware) that controls the operations of the refrigerant flow switching means 16a to 16c. Hardware and software) constitute the refrigerant flow path control means. Of course, the discharge capacity control means and the refrigerant flow path control means may be configured as separate control devices for the air conditioning control device 40.

  Next, the operation of the vehicle air conditioner 1 of the present embodiment having the above configuration will be described. In the vehicle air conditioner 1 of the present embodiment, switching to a cooling operation mode for cooling the vehicle interior, a heating operation mode for heating the vehicle interior, a defrost heating mode, and a dehumidifying heating mode for heating while dehumidifying the vehicle interior is performed. Can do. The operation in each operation mode will be described below.

(Heating mode)
The heating operation mode includes the following first heating mode and second heating mode, which are started when the heating operation mode is selected by the selection switch while the operation switch of the vehicle air conditioner is turned on. The

  When the heating operation mode is started, the air conditioning control device 40 reads the detection signal of the air conditioning control sensor group 41 and the operation signal of the operation panel, and the refrigerant discharge capacity of the compressor 11 (the rotation speed of the compressor 11). To decide. Further, the first heating mode or the second heating mode is executed according to the determined rotation speed.

(First heating mode)
First, the first heating mode will be described. When the first heating mode is executed, the air conditioning control device 40 sets the first variable throttle 13 in the throttle state, the third variable throttle 22 in the fully closed state, and the cooling on-off valve 16c in the valve open state.

  Further, the low-pressure side opening / closing valve 16b is closed, the low-stage pressure reducing means is set to a throttled state that exerts a pressure reducing action, and the intermediate pressure-side opening / closing valve 16a is opened in conjunction with the state of the low-pressure side opening / closing valve 16b. As a result, the heat pump cycle 10 is switched to the refrigerant flow path through which the refrigerant flows as shown by the solid line arrows in FIG. 1A.

  With this refrigerant flow path configuration (cycle configuration), the air conditioning control device 40 reads the detection signal of the sensor group 41 for air conditioning control and the operation signal of the operation panel, and based on the target blowing temperature TAO and the detection signal of the sensor group, The operating states of various air conditioning control devices connected to the output side of the air conditioning control device 40 are determined.

  In the first heating mode, the control signal output to the first variable throttle 13 is determined so that the throttle opening of the first variable throttle 13 becomes a predetermined opening for the first heating mode. The For the control signal output to the servo motor of the air mix door 34, the air mix door 34 closes the bypass passage 35, and the entire flow rate of the blown air after passing through the indoor evaporator 23 passes through the indoor condenser 12. To be determined.

Therefore, in the heat pump cycle 10 of the first heating mode, as shown in the Mollier diagram of FIG. 1B, the high-pressure refrigerant discharged from the discharge port 11c of compressor 11 (a _7-point) flows into indoor condenser 12. The refrigerant that has flowed into the indoor condenser 12 exchanges heat with air blown from the blower 32 and passes through the indoor evaporator 23 to dissipate heat (a ₇ → b ₇ points). Thereby, vehicle interior blowing air is heated.

The refrigerant that has flowed out of the indoor condenser 12 is decompressed and expanded in an enthalpy manner until it becomes an intermediate pressure refrigerant at the first variable throttle 13 that is in the throttle state (b ₇ → c ₁₇ point). The intermediate-pressure refrigerant decompressed by the first variable throttle 13 is gas-liquid separated by the gas-liquid separator 14 (c ₇ → c 2 ₇ points, c ₇ → c 3 ₇ points).

The gas-phase refrigerant separated by the gas-liquid separator 14 flows into the intermediate pressure port 11b of the compressor 11 through the intermediate pressure refrigerant passage 15 because the intermediate pressure side opening / closing valve 16a is in the open state. (C2 ₇ → a2 ₇ points), merged with the low-stage compression mechanism discharge refrigerant (a1 ₇ points) and sucked into the high-stage compression mechanism.

On the other hand, the liquid refrigerant separated by the gas-liquid separator 14 is decompressed and flows out until it becomes a low-pressure refrigerant in the low-stage decompression means because the low-stage decompression means is in the throttle state. It flows into the heat exchanger 20. That is, in the low stage pressure reducing means, since the low pressure side opening / closing valve 16b is closed, it is decompressed and expanded in an enthalpy manner until it flows into the second variable throttle 17 and becomes low pressure refrigerant (c3 ₇ → c4 ₇ points). Refrigerant flowing out of the second variable throttle 17, and flows into the outdoor heat exchanger 20, and outside air heat exchanger that has been blown from the blower fan 21 absorbs heat (c4 ₇ points → d ₇ points).

The refrigerant flowing out of the outdoor heat exchanger 20 flows into the accumulator 24 through the bypass passage 25 and is separated into gas and liquid because the cooling on-off valve 16c is in the open state. The separated gas-phase refrigerant is again compressed is sucked from the suction port 11a of the compressor 11 (e ₇ points). On the other hand, the separated liquid-phase refrigerant is stored in the accumulator 24 as surplus refrigerant that is not necessary for exhibiting the refrigerating capacity required for the cycle.

In FIG. 1B, d ₇ point and e ₇ point are different because the pressure loss generated in the gas-phase refrigerant flowing through the refrigerant pipe from the accumulator 24 to the suction port 11a of the compressor 11 and the gas-phase refrigerant are external. This represents the amount of heat absorbed from (outside air). Therefore, in an ideal cycle, it is desirable _{to 7} points and e ₇ points d match. The same applies to the following Mollier diagram.

  As described above, in the first heating mode, the heat of the refrigerant discharged from the compressor 11 by the indoor condenser 12 is dissipated to the vehicle interior blown air, and the heated room blown air is blown out into the vehicle interior. it can. Thereby, heating of a vehicle interior is realizable.

  Further, in the first heating mode, the low-pressure refrigerant decompressed by the second variable throttle 17 is sucked from the suction port 11a of the compressor 11, and the intermediate-pressure refrigerant decompressed by the first variable throttle 13 is sucked by the intermediate pressure port. A gas injection cycle (economizer refrigeration cycle) that flows into 11b and joins with the refrigerant in the pressure increasing process can be configured.

  Therefore, by allowing the high-stage compression mechanism to suck the refrigerant mixture having a low temperature, the compression efficiency of the high-stage compression mechanism can be improved, and both the low-stage compression mechanism and the high-stage compression mechanism can be improved. By reducing the pressure difference between the suction refrigerant pressure and the discharge refrigerant pressure, it is possible to improve the compression efficiency of both compression mechanisms. As a result, the COP of the heat pump cycle 10 as a whole can be improved.

(Second heating mode)
Next, the second heating mode will be described. When the second heating mode is executed, the air conditioning control device 40 sets the first variable throttle 13 to a throttle state that exerts a pressure reducing action, sets the third variable throttle 22 to a fully closed state, and sets the cooling on-off valve 16c. Open the valve.

  Further, the low-pressure side opening / closing valve 16b is opened, the low-stage pressure reducing means is fully opened without exerting the pressure reducing action, and the intermediate pressure-side opening / closing valve 16a is closed in conjunction with the state of the low-pressure side opening / closing valve 16b. . The heat pump cycle 10 is switched to the refrigerant flow path through which the refrigerant flows as shown by the solid line arrows in FIG. 2A.

  With this refrigerant flow path configuration (cycle configuration), the air conditioning control device 40 determines the operating states of various air conditioning control devices and air conditioning units connected to the output side of the air conditioning control device 40 as in the first heating mode.

In the heat pump cycle 10 of the second heating mode, as shown in the Mollier diagram of FIG. 2B, the high-pressure refrigerant discharged from the discharge port 11c of compressor 11 ₍₈ a) flows into the indoor condenser 12, the As in the 2 heating mode, heat is exchanged with the air blown into the passenger compartment to dissipate heat (a ₈ → b ₈ points). Thereby, vehicle interior blowing air is heated.

The refrigerant that has flowed out of the indoor condenser 12 is decompressed and expanded in an enthalpy manner (b ₈ → c ₈ points) until it becomes a low-pressure refrigerant in the first variable throttle 13 that is in the throttle state, and the gas-liquid separator 14 Flow into. At this time, the refrigerant flowing into the gas-liquid separator 14 flows out from the liquid-phase refrigerant outflow port 14d without being separated into gas and liquid because the intermediate pressure side opening / closing valve 16a is closed.

On the other hand, the liquid-phase refrigerant separated by the gas-liquid separator 14 flows out with almost no decompression by the low-stage decompression means because the low-stage decompression means is fully open, and the outdoor heat exchange Flow into the vessel 20. That is, in the low stage pressure reducing means, the low pressure side opening / closing valve 16b is in the open state, and therefore flows into the outdoor heat exchanger 20 through the bypass passage 18 without flowing into the second variable throttle 17 side. . The low-pressure refrigerant flowing into the outdoor heat exchanger 20, and outside air heat exchange, which is blown from the blower fan 21 absorbs heat (c ₈ points → d ₈ points). The subsequent operation is the same as in the first heating mode.

  Here, the effect of executing the second heating mode when the heating load is relatively low, such as when the outside air temperature is high, is described with respect to the first heating mode. Theoretically, if the rotation speed of the compressor 11 is the same, the first heating mode can exhibit higher heating performance than that in the second heating mode. In other words, the rotation speed (refrigerant discharge capacity) of the compressor 11 necessary for exhibiting the same heating performance is lower in the second heating mode than in the first heating mode.

  However, the compression mechanism has a maximum efficiency rotational speed at which the compression efficiency is maximized (peak), and the compression efficiency is greatly reduced when the rotational speed is lower than the maximum efficient rotational speed. For this reason, when the compressor 11 is operated at a rotation speed lower than the maximum efficiency rotation speed when the heating load is relatively low, the COP may decrease in the first heating mode.

  Therefore, in the present embodiment, when the rotation speed of the compressor 11 becomes equal to or less than the reference rotation speed during execution of the first heating mode with the above-described maximum efficiency rotation speed as the reference rotation speed, the second heating mode is entered. Switching to the first heating mode is performed when the rotation speed becomes equal to or higher than the rotation speed obtained by adding a predetermined amount to the reference rotation speed during execution of the second heating mode.

  Thereby, the operation mode which can exhibit high COP is selected among 1st heating mode and 2nd heating mode. Therefore, even when the rotation speed of the compressor 11 becomes equal to or lower than the reference rotation speed during the execution of the first heating mode, the COP of the heat pump cycle 10 as a whole is improved by switching to the second heating mode. Can be made.

(Defrost heating mode)
When the heating mode is performed, the outdoor heat exchanger 20 functions as an evaporator. Therefore, when condensed water is generated and the outdoor temperature is relatively low, the condensed water is frozen and the outdoor heat exchanger 20 is frosted. Occurs. Here, since the frosting can occur even when the heating mode is the first and second heating modes, any of the defrosting heating modes of this embodiment can be applied. Here, the case of the 1st heating mode often performed at the time of low temperature is mentioned as an example, and is demonstrated below. When the frosting state of the outdoor heat exchanger 20 is determined by the air conditioning control device 40, as shown in FIG. 3, the first heating mode is changed to the defrosting heating mode, and the vehicle interior ventilation is performed by the indoor condenser 12. While heating the air, the outdoor heat exchanger 20 dissipates the heat of the hot gas refrigerant and melts the frosted ice so that the hot gas can be defrosted while the vehicle interior is heated.

  The frost formation state of the outdoor heat exchanger 20 can be determined by various means. When the outdoor heat exchanger 20 is frosted, the outlet refrigerant temperature Tho of the outdoor heat exchanger 20 detected by the outlet refrigerant temperature sensor 41-2 decreases. In this embodiment, when the difference Tam−Th between the outside air temperature Tam and the outlet refrigerant temperature Th becomes larger than a predetermined value (for example, 20 ° C. or the like), it is determined that the outdoor heat exchanger 20 is frosted. By this determination, the first heating mode is changed to the defrost heating mode. As a determination means, when Tam-Tho continues for a predetermined time (for example, about 10 minutes) or more at a predetermined temperature difference (for example, 15 ° C. or the like), the frosting state may be determined. The determination of the frosting state is not limited to these, and may be determined by other well-known means (paragraph 0042 of JP-A-2000-203249, paragraph 0057 of JP-A-2001-246930, etc.).

  Next, control for changing from the first heating mode to the defrosting heating mode will be described with reference to FIG. This control is the same except for the intermediate injection portion even when the second heating mode is changed to the defrosting heating mode. The upper diagram of FIG. 3 is the same as FIG. 1B. In the first heating mode, the outdoor heat exchanger 20 absorbs heat from the outside air.

  As illustrated in this figure, when the outside air temperature is close to 0 ° C., frost formation occurs in the outdoor heat exchanger 20. When the frost formation state is determined, in order to change to the refrigeration cycle shown in the lower diagram of FIG. 3, that is, to change the outdoor heat exchanger 20 from heat absorption to heat dissipation, first, a command is sent to the blower 32 of the indoor air conditioning unit 30. Then, the air flow rate is reduced. Then, the heat exchange amount in the indoor condenser 12 starts to decrease. The cooling amount of the refrigerant that has been heat-exchanged in the indoor condenser 12 decreases, and the enthalpy h at the outlet of the indoor condenser 12 shifts to the right-hand side in FIG. 3 and is sent to the outdoor heat exchanger 20. The enthalpy of the refrigerant is rising. At the same time, the opening of the first variable throttle 13 is controlled to open. At this time, the opening degree of the first variable throttle 13 needs to correspond to the change from the liquid refrigerant to the gas refrigerant. At this time, not the liquid phase refrigerant but the gas phase refrigerant flows out from the liquid phase refrigerant outlet 14 d of the gas-liquid separator 14 to the second variable throttle 17.

Further, in the first heating mode, the valve opening of the second variable throttle 17 is also adjusted at the same time so that the intermediate pressure becomes appropriate (in the second heating mode, the opening is adjusted by the opening of the first variable throttle 13). In addition to these controls, it is preferable to perform control to increase the rotational speed of the compressor 11 at the same time.
As a result of the above adjustment, when the temperature of the refrigerant flowing into the outdoor heat exchanger 20 eventually becomes higher than the outside air temperature, the refrigerant is no longer separated from the heat pump cycle, and the outdoor heat exchanger 20 can no longer absorb heat. And it transfers to the hot gas cycle of the lower figure of FIG. 3, and it begins to thermally radiate the heat | fever of a hot gas refrigerant | coolant in the outdoor heat exchanger 20 (defrost heating mode), and it comes to melt | dissolve the frosted ice.

  In the hot gas cycle, energy given to the refrigerant from the compressor is distributed to heating and defrosting. That is, how energy (enthalpy × flow rate) is given to the refrigerant is related to the heating performance and the defrosting performance. In addition, in the hot gas cycle, the latent heat cannot be used and heating is performed by sensible heat, so that the heating capacity in the passenger compartment may be insufficient. Therefore, in the defrost heating mode, it is preferable to increase the heating capacity in the passenger compartment by performing injection at an intermediate pressure and increasing the flow rate of the refrigerant flowing through the indoor condenser 12. In particular, when HFC, HFO refrigerants (R134a, R1234yf, etc.) are used, the defrosting heating mode that performs injection at an intermediate pressure is powerful because the heating capacity in the hot gas cycle is small. Demonstrate. Therefore, in this embodiment, it is not only a mere defrost mode, but has a feature as a defrost heating mode in which sufficient heating can be performed even during defrosting.

  In addition to the above control, it is also possible to control by the following sequence. If it is determined that the frosting state occurs during the operation in the first heating mode, first, the first and second variable throttles 13 and 17 are controlled to open. The cycle is operated so that the high pressure decreases and the low pressure increases, but the rotational speed of the compressor 11 is increased so that the high pressure does not decrease. Still, when the high-pressure side of the refrigeration cycle is lowered and the temperature of the blowout into the passenger compartment is lowered, the air volume is lowered for the first time, and the blowout temperature is maintained. Thereby, heating can be continued without affecting the heating function in the passenger compartment. Eventually, when the low pressure side of the refrigeration cycle rises and the temperature of the refrigerant flowing into the outdoor heat exchanger exceeds 0 ° C., the defrosting heating mode is started and defrosting starts, and the cycle shown in the lower diagram of FIG. Operate to balance.

  As described above, according to the present embodiment, it is not necessary to use an evaporator as a heater, and therefore, re-evaporation of retained condensed water does not occur. Therefore, it does not cause problems of bad odor and window fogging. In addition, when performing gas injection in the defrost heating mode, the flow rate of the compressor increases, and the energy given to the refrigerant can be increased. During the hot gas cycle, the throttle opening is controlled to be opened by the first variable throttle 13 and the second variable throttle 17, so that the gas throttle can be operated with a good opening.

  The first embodiment of the present invention can be applied to any vehicle air conditioner having at least the first heating mode or the second heating mode and the above-described defrosting heating mode. In the case of the present embodiment, it further has the following cooling operation mode and dehumidification heating operation mode, and these modes will be described below.

(Cooling operation mode)
The cooling operation mode is started when the operation switch on the operation panel is turned on (ON) and the cooling operation mode is selected by the selection switch. In the cooling operation mode, the air-conditioning control device 40 sets the first variable throttle 13 to a fully open state that does not exert a pressure reducing action, sets the third variable throttle 22 to a throttled state that exerts a pressure reducing action, and closes the cooling on-off valve 16c. State.

  Further, the low-pressure side opening / closing valve 16b is opened, the low-stage pressure reducing means is fully opened so as not to exert a pressure reducing action, and the intermediate pressure-side opening / closing valve 16a is closed in conjunction with the state of the low-pressure side opening / closing valve 16b. . As a result, the heat pump cycle 10 is switched to the refrigerant flow path through which the refrigerant flows as shown by the solid line arrows in FIG. 4A.

  With this refrigerant flow path configuration, the air conditioning controller 40 reads the detection signal of the air conditioning control sensor group 41 and the operation signal of the operation panel, calculates the target blowing temperature TAO, and calculates the calculated target blowing temperature TAO and Based on the detection signal of the sensor group, the operating state of various air conditioning control devices connected to the output side of the air conditioning control device 40 is determined.

  For example, the refrigerant discharge capacity of the compressor 11, that is, the control signal output to the electric motor of the compressor 11 is determined as follows. First, the target evaporator outlet temperature TEO of the indoor evaporator 23 is determined based on the target outlet temperature TAO with reference to a control map stored in the air conditioning controller 40 in advance.

  And based on the deviation of this target evaporator blowing temperature TEO and the blowing air temperature from the indoor evaporator 23 detected by the evaporator temperature sensor, the blowing air temperature from the indoor evaporator 23 is determined using a feedback control method. A control signal output to the electric motor of the compressor 11 is determined so as to approach the target evaporator outlet temperature TEO.

  As for the control signal output to the third variable throttle 22, the degree of supercooling of the refrigerant flowing into the third variable throttle 22 approaches the target supercooling degree determined in advance so that the COP approaches the substantially maximum value. To be determined. Regarding the control signal output to the servo motor of the air mix door 34, the air mix door 34 closes the air passage of the indoor condenser 12, and the total flow rate of the blown air after passing through the indoor evaporator 23 is the bypass passage 35. Is determined to pass.

  Then, the control signal determined as described above is output to various air conditioning control devices. After that, until the operation of the vehicle air conditioner is requested by the operation panel, the above detection signal and operation signal are read at every predetermined control cycle → the target blowout temperature TAO is calculated → the operating states of various air conditioning control devices are determined -> Control routines such as control voltage and control signal output are repeated. Such a control routine is repeated in the other operation modes.

Therefore, in the heat pump cycle 10 of the cooling operation mode, as shown in the Mollier diagram of FIG. 4B, the high-pressure refrigerant discharged from the discharge port 11c of compressor 11 (a ₆ points) flows into indoor condenser 12. At this time, since the air mix door 34 closes the air passage of the indoor condenser 12, the refrigerant flowing into the indoor condenser 12 flows out of the indoor condenser 12 without radiating heat to the vehicle interior air. Go.

  The refrigerant flowing out of the indoor condenser 12 flows in the order of the first variable throttle 13 → the gas-liquid separator 14 → the low-pressure side opening / closing valve 16 b and flows into the outdoor heat exchanger 20. More specifically, since the first variable throttle 13 is fully opened, the refrigerant that has flowed out of the indoor condenser 12 flows out almost without being depressurized by the first variable throttle 13, and the gas-liquid separator 14. The refrigerant flows into the gas-liquid separator 14 from the refrigerant inflow port 14b.

  Here, as described above, the throttle opening degree of the third variable throttle 22 is determined so that the supercooling degree of the refrigerant flowing into the third variable throttle 22 approaches the target supercooling degree. The refrigerant flowing into the liquid phase is in a liquid phase state having a degree of supercooling. Accordingly, the gas-liquid separator 14 does not separate the gas-liquid refrigerant, and the liquid-phase refrigerant flows out from the liquid-phase refrigerant outflow port 14d. Furthermore, since the intermediate pressure side on-off valve 16a is in the closed state, the liquid phase refrigerant does not flow out from the gas phase refrigerant outflow port 14c.

The liquid-phase refrigerant that has flowed out of the liquid-phase refrigerant outflow port 14d flows out to the outdoor heat exchanger 20 because the low-stage depressurizing means is fully opened, and is almost not depressurized by the low-stage depressurizing means. Inflow. That is, in the low stage pressure reducing means, since the low pressure side opening / closing valve 16b is in the open state, it flows into the outdoor heat exchanger 20 through the bypass passage 18 without flowing into the second variable throttle 17 side. Low-pressure refrigerant flowing into the outdoor heat exchanger 20, radiates heat to outdoor air heat exchanger that has been blown from the blower fan 21 (a _6-point → b ₆ points).

The refrigerant that has flowed out of the outdoor heat exchanger 20 is isoenthalpy until it flows into the third variable throttle 22 that is in a throttled state and becomes a low-pressure refrigerant because the cooling on-off valve 16c is in a closed state. reduced pressure is expanded to (b ₆ points → c ₆ points). The low-pressure refrigerant decompressed by the third variable throttle 22 flows into the indoor evaporator 23, and absorbs heat from the air in-room air blown from the blower 32 to evaporate (c ₆ points → d ₆ points). Thereby, vehicle interior blowing air is cooled.

The refrigerant flowing out of the indoor evaporator 23 flows into the accumulator 24 and is separated into gas and liquid. The separated gas-phase refrigerant is compressed again in the order of inhaled by the low-stage compression mechanism → the high-stage compression mechanism from the intake port 11a of the compressor 11 (e ₆ points) (e ₆ points → a1 ₆ points → a ₆ points). On the other hand, the separated liquid-phase refrigerant is stored in the accumulator 24 as surplus refrigerant that is not necessary for exhibiting the refrigerating capacity required for the cycle.

  Here, the reason why the intermediate pressure side on-off valve 16a is closed in the cooling operation mode will be described. In the cooling operation mode, as described above, both the first variable throttle 13 and the low stage pressure reducing means are in a fully open state in which the pressure reducing action is not exhibited. For this reason, when the intermediate pressure side opening / closing valve 16a is opened and the gas injection cycle is realized, the gas-phase refrigerant discharged from the discharge port 11c of the compressor 11 is changed to the indoor condenser 12 → intermediate pressure refrigerant passage 15 → intermediate pressure. This is because it simply repeats that it flows in the order of the port 11b and is compressed again by the compressor 11, and does not function effectively for cooling the passenger compartment, and simply consumes energy of the compressor 11. . Thus, in this embodiment, in order to reduce the wasteful energy consumption of the compressor 11, the intermediate pressure side on-off valve 16a is closed in the cooling operation mode.

(Dehumidifying heating operation mode)
Next, the dehumidifying and heating operation mode will be described. The dehumidifying and heating operation mode is executed when the set temperature set by the vehicle interior temperature setting switch in the cooling operation mode is set to a temperature higher than the outside air temperature.

  When the dehumidifying and heating mode is executed, the air conditioning control device 40 sets the first variable throttle 13 to a fully open state or throttle state, sets the third variable throttle 22 to a fully open state or throttle state, and closes the cooling on-off valve 16c. And

  Further, the low-pressure side opening / closing valve 16b is opened, the low-stage pressure reducing means is fully opened without exerting a pressure reducing action, and the intermediate pressure-side opening / closing valve 16a is closed in conjunction with the state of the low-pressure side opening / closing valve 16b. As a result, the heat pump cycle 10 is switched to the refrigerant flow path through which the refrigerant flows as indicated by the solid line arrows in FIG. 4A similar to the cooling operation mode. For the control signal output to the servo motor of the air mix door 34, the air mix door 34 closes the bypass passage 35, and the entire flow rate of the blown air after passing through the indoor evaporator 23 passes through the indoor condenser 12. To be determined.

  Furthermore, in the dehumidifying and heating mode of the present embodiment, the opening degrees of the first variable throttle 13 and the third variable throttle 22 are changed according to the temperature difference between the set temperature and the outside air temperature. Specifically, as the target blowout temperature TAO is increased, the throttle opening of the first variable throttle 13 is decreased and the throttle opening of the third variable throttle 22 is increased. A four-stage dehumidifying heating mode is executed from the dehumidifying heating mode to the fourth dehumidifying heating mode.

(First dehumidifying heating mode)
In the first dehumidifying and heating mode, the first variable throttle 13 is in a fully open state, and the third variable throttle 22 is in a throttle state. Therefore, although the cycle configuration (refrigerant flow path) is exactly the same as that in the cooling operation mode, the air mix door 34 fully opens the air passage of the indoor condenser 12, so that the state of the refrigerant circulating in the cycle is It changes as shown in the Mollier diagram of FIG. 5A.

  As described above, in the first dehumidifying / heating mode, the vehicle interior blown air cooled and dehumidified by the indoor evaporator 23 can be heated by the indoor condenser 12 and blown out into the vehicle interior. Thereby, dehumidification heating of a vehicle interior is realizable.

(Second dehumidifying heating mode)
Next, when the target blowing temperature TAO becomes higher than the predetermined first reference temperature during the execution of the first dehumidifying and heating mode, the second dehumidifying and heating mode is executed. In the second dehumidifying and heating mode, the first variable throttle 13 is set to the throttled state, and the throttle opening of the third variable throttle 22 is set to the throttled state in which the throttle opening is increased compared to the first dehumidifying and heating mode. Therefore, in the second dehumidifying and heating mode, the state of the refrigerant circulating in the cycle changes as shown in the Mollier diagrams of FIGS. 5B and 6A.

That is, as shown in FIG. 5B, (a ₁₀ point in FIG. 11) the high-pressure refrigerant discharged from the discharge port 11c of compressor 11, as in the first dehumidification and heating mode, and flows into indoor condenser 12, inside evaporator 23 and the cabin air blown heat exchange with dehumidified is cooled by radiating heat ₍₁₀ → b1 ₁₀ a). Thereby, vehicle interior blowing air is heated.

The refrigerant that has flowed out of the indoor condenser 12 is decompressed in an enthalpy manner (b1 ₁₀ points → b2 ₁₀ points) by the first variable throttle 13 in the throttled state until it becomes intermediate pressure refrigerant. The intermediate-pressure refrigerant decompressed by the first variable throttle 13 flows in the order of the gas-liquid separator 14 → the low-pressure side opening / closing valve 16 b of the low-stage decompression means, and flows into the outdoor heat exchanger 20.

6A, the low-pressure refrigerant that has flowed into the outdoor heat exchanger 20 exchanges heat with the outside air blown from the blower fan 21 to dissipate heat (b2 ₁₀ points → b3 ₁₀ points).
The subsequent operation is the same as in the cooling operation mode.

  As described above, in the second dehumidifying and heating mode, as in the first dehumidifying and heating mode, the vehicle interior blown air that has been cooled and dehumidified by the indoor evaporator 23 is heated by the indoor condenser 12 into the vehicle interior. Can be blown out. Thereby, dehumidification heating of a vehicle interior is realizable.

  At this time, in the second dehumidifying and heating mode, since the first variable throttle 13 is in the throttled state, the temperature of the refrigerant flowing into the outdoor heat exchanger 20 can be lowered compared to the first dehumidifying and heating mode. Therefore, the temperature difference between the temperature of the refrigerant in the outdoor heat exchanger 20 and the outside air temperature can be reduced, and the amount of heat released from the refrigerant in the outdoor heat exchanger 20 can be reduced.

  As a result, since the amount of refrigerant in the indoor condenser 12 can be increased, the temperature blown out from the indoor condenser 12 can be increased more than in the first dehumidifying and heating mode.

(Third dehumidifying heating mode)
Next, when the target blowing temperature TAO becomes higher than the predetermined second reference temperature during the execution of the second dehumidifying and heating mode, the third dehumidifying and heating mode is executed. In the third dehumidifying and heating mode, the throttle opening of the first variable throttle 13 is set to a throttled state that is reduced compared to the second dehumidifying and heating mode, and the throttle opening of the third variable throttle 22 is increased more than in the second dehumidifying and heating mode. . Therefore, in the third dehumidifying heating mode, the state of the refrigerant circulating in the cycle changes as shown in the Mollier diagrams of FIGS. 5C and 6B.

That is, as shown in FIG. 5C, the high-pressure refrigerant discharged from the discharge port 11c of compressor 11 (a _11-point) is, like the first and second dehumidification and heating mode, and flows into indoor condenser 12, inside evaporator 23 and the cabin air blown heat exchange with dehumidified is cooled by radiating heat (a ₁₁ point → b ₁₁ points). Thereby, vehicle interior blowing air is heated.

The refrigerant flowing out of the indoor condenser 12 is decompressed in an enthalpy manner until it becomes an intermediate pressure refrigerant having a temperature lower than the outside air temperature by the first variable throttle 13 in the throttle state (b ₁₁ point → c _{11 11} point). ). The intermediate-pressure refrigerant decompressed by the first variable throttle 13 flows in the order of the gas-liquid separator 14 → the low-pressure side opening / closing valve 16 b of the low-stage decompression means, and flows into the outdoor heat exchanger 20.

Then, as shown in FIG. 6B, the low-pressure refrigerant flowing into the outdoor heat exchanger 20, and outside air heat exchange, which is blown from the blower fan 21 absorbs heat (c1 ₁₁ points → c2 ₁₁ points). Furthermore, the refrigerant that has flowed out of the outdoor heat exchanger 20 is decompressed in an enthalpy manner by the third variable throttle 22 (c2 ₁₁ point → c3 ₁₁ point), and flows into the indoor evaporator 23. The subsequent operation is the same as in the cooling operation mode.

  In the third dehumidifying and heating mode, the outdoor heat exchanger 20 is operated as an evaporator by reducing the throttle opening of the first variable throttle 13, so that the indoor condenser 12 is compared with the second dehumidifying and heating mode. The amount of refrigerant in can be increased. As a result, the temperature blown out from the indoor condenser 12 can be increased more than in the second dehumidifying and heating mode.

(4th dehumidifying heating mode)
Next, when the target blowing temperature TAO becomes higher than a predetermined third reference temperature during execution of the third dehumidifying heating mode, the fourth dehumidifying heating mode is executed. In the fourth dehumidifying and heating mode, the throttle opening degree of the first variable throttle 13 is made smaller than that in the third dehumidifying and heating mode, and the third variable throttle 22 is fully opened. Therefore, in the fourth dehumidifying heating mode, the state of the refrigerant circulating in the cycle changes as shown in the Mollier diagram of FIG. 5D.

That is, as shown in FIG. 5D, the high-pressure refrigerant (a ₁₂ point) discharged from the discharge port 11c of compressor 11, first, similarly to the second dehumidification and heating mode, and flows into indoor condenser 12, inside evaporator 23 and the cabin air blown heat exchange with dehumidified is cooled by radiating heat (a ₁₂ point → b ₁₂ points). Thereby, vehicle interior blowing air is heated.

The refrigerant flowing from the indoor condenser 12 is isenthalpic depressurize until low pressure refrigerant temperature than the outside air temperature by the first variable throttle 13 which is the stop state (b ₁₂ points → c1 ₁₂ points) . The intermediate-pressure refrigerant decompressed by the first variable throttle 13 flows in the order of the gas-liquid separator 14 → the low-pressure side opening / closing valve 16 b of the low-stage decompression means, and flows into the outdoor heat exchanger 20.

The low-pressure refrigerant flowing into the outdoor heat exchanger 20 exchanges heat with the outside air blown from the blower fan 21 and absorbs heat (c1 ₁₂ points → c2 ₁₂ points). Furthermore, the refrigerant that has flowed out of the outdoor heat exchanger 20 flows into the indoor evaporator 23 without being reduced in pressure because the third variable throttle 22 is fully opened. The subsequent operation is the same as in the cooling operation mode.

  At this time, in the fourth dehumidifying and heating mode, the outdoor heat exchanger 20 is caused to act as an evaporator as in the third dehumidifying and heating mode, and the throttle opening of the first variable throttle 13 is reduced as compared with the third dehumidifying and heating mode. Therefore, the refrigerant evaporation temperature in the outdoor heat exchanger 20 can be lowered. Therefore, the amount of refrigerant in the indoor condenser 12 can be increased by expanding the temperature difference between the refrigerant temperature and the outside air temperature in the outdoor heat exchanger 20 as compared with the third dehumidifying and heating mode.

  As a result, the temperature blown out from the indoor condenser 12 can be increased more than in the third dehumidifying and heating mode.

  Here, the reason why the intermediate pressure side on-off valve 16a is closed in the dehumidifying and heating operation mode will be described. When the gas injection cycle is realized in the dehumidifying heating operation mode, the refrigerant flowing in the intermediate pressure refrigerant passage 15 is caused by the differential pressure between the refrigerant pressure in the gas-liquid separator 14 and the refrigerant pressure in the intermediate pressure port 11b of the compressor 11. The flow rate changes. To change the flow rate of the refrigerant flowing through the intermediate pressure refrigerant passage 15, the amount of heat released from the refrigerant in the indoor condenser 12 changes, making it difficult to adjust the temperature of the blown air, and to appropriately adjust the temperature of the blown air. This is because the cycle configuration and various controls become complicated.

  In particular, when the throttle openings of the first variable throttle 13 and the third variable throttle 22 are changed according to the target blowing temperature TAO as in the dehumidifying and heating operation mode of the present embodiment, the intermediate pressure side on-off valve 16a is set to the open state. If the gas injection cycle is realized, the target blowing temperature TAO and the flow rate of the refrigerant flowing through the intermediate pressure refrigerant passage 15 are in a contradictory relationship, making it difficult to adjust the temperature of the blown air.

  For example, among the first to fourth dehumidifying heating operation modes, in the first dehumidifying heating operation mode executed when the target blowing temperature TAO is the lowest, the first variable throttle 13 is fully opened, and the refrigerant in the gas-liquid separator 14 The differential pressure between the pressure and the refrigerant pressure at the intermediate pressure port 11b of the compressor 11 is maximized. As a result, the flow rate of the refrigerant flowing through the intermediate pressure refrigerant passage 15 increases, the amount of heat release in the indoor condenser 12 increases, and it becomes difficult to lower the temperature of the blown air.

  Moreover, in the 4th dehumidification heating operation mode performed when the target blowing temperature TAO is the highest among the 1st-4th dehumidification heating operation modes, the 1st variable throttle 13 will be in a throttle state, and the refrigerant | coolant in the gas-liquid separator 14 will be shown. The differential pressure between the pressure and the refrigerant pressure at the intermediate pressure port 11b of the compressor 11 is minimized. As a result, the flow rate of the refrigerant flowing through the intermediate pressure refrigerant passage 15 decreases, the amount of heat released in the indoor condenser 12 decreases, and it becomes difficult to raise the temperature of the blown air.

  Thus, in the present embodiment, the intermediate pressure side on-off valve 16a is closed in the dehumidifying and heating operation mode in order to prevent the cycle configuration and control when adjusting the temperature of the blown air from becoming complicated.

  In the dehumidifying and heating operation mode, the reason why the low-stage decompression means is in a fully open state that does not exert a decompression action is that when the low-stage decompression means is in the throttle state, the amount of heat absorbed and radiated in the outdoor heat exchanger 20 This is because the adjustment range is limited, and it is difficult to adjust the temperature of the blown air.

  As described above, in the dehumidifying and heating operation mode of the present embodiment, the intermediate pressure side opening / closing valve 16a is closed, and the low stage pressure reducing means is fully opened so as not to exert a pressure reducing action. In addition to suppressing the complexity of the cycle configuration and control when adjusting the air flow, the temperature of the blown air is finely adjusted.

  In the vehicle air conditioner 1 of the present embodiment described above, both the first variable throttle 13 and the low-stage decompression means can be set to a fully open state that does not exhibit a decompression action. For this reason, the refrigerant flow path from the compressor 11 to the outdoor heat exchanger 20 is not separately provided according to each operation mode of the vehicle air conditioner 1, and the state of the first variable throttle 13 and the low-stage decompression means By changing the (throttle state, fully open state), the heat exchange amount (heat absorption amount and heat release amount) between the refrigerant and the outside air in the outdoor heat exchanger 20 can be adjusted according to each operation mode.

  Therefore, in the heat pump cycle constituting the gas injection cycle, cooling, heating, and dehumidifying heating can be realized with a simple cycle configuration.

  In this embodiment, since the intermediate pressure side on / off valve 16a for opening and closing the intermediate pressure refrigerant passage 15 is provided, the heat pump cycle is changed to the gas injection cycle by opening and closing the intermediate pressure refrigerant passage 15 by the intermediate pressure side on / off valve 16a. And a normal cycle (one-stage compression cycle).

  Further, in the present embodiment, in the cooling operation mode and the dehumidifying heating operation mode, the intermediate pressure refrigerant passage 15 is closed by the intermediate pressure side opening / closing valve 16a, and the heat pump cycle 10 is switched to the normal cycle.

  Thus, in the cooling operation mode, if the intermediate pressure refrigerant passage 15 is closed and the heat pump cycle is switched to the normal cycle, useless energy consumption of the compressor 11 can be reduced.

  Further, in the dehumidifying and heating operation mode, if the intermediate pressure refrigerant passage 15 is closed and the heat pump cycle is switched to the normal cycle, the adjustment of the calorific value of the refrigerant in the indoor condenser 12 is facilitated, and the configuration is simple. Appropriate temperature adjustment of the blown air can be realized.

  In particular, in the present embodiment, in the dehumidifying and heating operation mode, the throttle openings of the first variable throttle 13 and the third variable throttle 22 are changed according to the target outlet temperature TAO, so that the refrigerant in the indoor condenser 12 is changed. The amount of heat release and the amount of heat absorbed by the refrigerant in the indoor evaporator 23 can be adjusted appropriately, and an extremely fine temperature adjustment of the blown air can be realized with a simple configuration.

  In the heating operation mode, the intermediate pressure refrigerant passage 15 is opened by the intermediate pressure side opening / closing valve 16a and the heat pump cycle is switched to the gas injection cycle, so that the coefficient of performance (COP) of the cycle can be improved.

  Furthermore, in the vehicle air conditioner 1 applied to the electric vehicle as in the present embodiment, the waste heat of the engine cannot be used for heating the vehicle interior as in a vehicle equipped with an internal combustion engine (engine). Therefore, it is extremely effective that a high COP can be exhibited regardless of the heating load in the heating operation mode as in the heat pump cycle 10 of the present embodiment.

  Further, in the heat pump cycle 10 of the present embodiment, the centrifugal gas-liquid separator 14 is employed as the gas-liquid separating means, and the internal volume of the gas-liquid separator 14 is made smaller than the surplus refrigerant volume. The physique of the liquid separating means can be reduced in size, and the mountability of the heat pump cycle 10 on the vehicle as a whole can be improved. Furthermore, even if a load fluctuation occurs in the cycle, surplus refrigerant can be stored in the accumulator 24, so that the cycle can be stably operated.

  The centrifugal gas-liquid separator 14 employed in the heat pump cycle 10 of the present embodiment has a higher gas-liquid separation performance as the refrigerant flow rate increases, and is therefore operated at a relatively high load. It is effective when applied to the heat pump cycle 10 having a high frequency.

(Second Embodiment)
In the first embodiment, the low-stage decompression means refers to a combination of the second variable throttle 17 and the low-pressure side on-off valve 16b inserted in parallel therewith. In the second embodiment, as shown in FIG. 7, one second variable throttle 17 with a fully open function is used, and the second variable throttle 17 is controlled and opened in the first heating mode and the defrost heating mode. Use as a pressure reducing device. In the second heating mode, the cooling mode, etc., the second variable throttle 17 is used at the fully open position. The operation and effect are the same as in the first embodiment. The solid arrow in FIG. 7 indicates the refrigerant flow path in the second heating mode (second variable throttle 17: full opening), and the arrow combined with the solid arrow and the dotted arrow indicates the refrigerant flow path in the first heating mode. (2nd variable aperture 17: control opening degree) is shown.

(Third embodiment)
This embodiment demonstrates the example which changed the cycle structure of the heat pump cycle 10 with respect to 1st Embodiment. The heat pump cycle 10 of the present embodiment does not directly radiate the heat of the high-pressure refrigerant discharged from the discharge port 11c of the compressor 11 to the blown air, but radiates it to the blown air via a heat medium made of an antifreeze liquid or the like. It is configured to do.

  Specifically, as shown in the overall configuration diagram of FIG. 8, the refrigerant that radiates the heat of the high-pressure refrigerant discharged from the discharge port 11c of the compressor 11 to the heat pump cycle 10 to the heat medium for heating the blown air. The radiator 52 is provided.

  In addition, the indoor air conditioning unit 30 is provided with a heating heat exchanger 12 ′ that radiates the heat of the heat medium heated by the refrigerant radiator 52 to the blown air and heats the blown air. The heating heat exchanger 12 ′ is connected to the refrigerant radiator 52 via the heat medium circulation circuit 50, and the heat medium is pumped by a pressure pump 51 provided in the heat medium circulation circuit 50.

  If comprised in this way, since it becomes the structure which arrange | positions the refrigerant | coolant heat radiator 52 outside the indoor air conditioning unit 30, it will be possible to apply this embodiment, without changing the internal structure of the present indoor air conditioning unit 30. Become. This is effective in that the cost for constructing the system of the air conditioner can be suppressed.

(Fourth embodiment)
This embodiment demonstrates the example which changed the structure of the intermediate pressure side on-off valve 16a with respect to 1st Embodiment with reference to FIG. 9A-9C. In the present embodiment, the intermediate pressure side on / off valve 16a is constituted by a differential pressure on / off valve that opens and closes the intermediate pressure refrigerant passage 15 in accordance with the differential pressure across the second variable throttle 17 of the low stage pressure reducing means.

  The intermediate pressure side on / off valve 16a of the present embodiment is configured by a differential pressure on / off valve that closes the intermediate pressure refrigerant passage 15 when the differential pressure before and after the second variable throttle 17 becomes equal to or higher than a predetermined set pressure α. ing.

  Specifically, as shown in the upper part of FIG. 9A, the intermediate pressure side opening / closing valve 16a closes the low pressure side opening / closing valve 16b of the low stage side pressure reducing means, and the differential pressure across the second variable throttle 17 increases to set pressure. The intermediate pressure refrigerant passage 15 is configured to be opened when it becomes α or more.

  Further, as shown in the lower part of FIG. 9A, the intermediate pressure side opening / closing valve 16a is opened by the low pressure side opening / closing valve 16b of the low stage side pressure reducing means, and the differential pressure across the second variable throttle 17 is reduced to be less than the set pressure α. When this happens, the intermediate pressure refrigerant passage 15 is closed.

  In the heat pump cycle 10 of the present embodiment configured as described above, in the cooling operation mode and the dehumidifying heating operation mode in which the low-pressure side opening / closing valve 16b is opened and the low-stage decompression unit is fully opened without exhibiting the decompression action. The differential pressure across the second variable throttle 17 becomes less than the set pressure α, and the intermediate pressure side on-off valve 16a is closed. As a result, the heat pump cycle 10 is switched to the refrigerant flow path of the normal cycle in which the refrigerant does not flow through the intermediate pressure refrigerant passage 15 as shown in the overall configuration diagram (solid arrow) in FIG. 9B.

  Further, in the heat pump cycle 10 of the present embodiment, the difference between the front and rear of the second variable throttle 17 in the heating operation mode in which the low-pressure side opening / closing valve 16b is closed and the low-stage pressure reducing means is in the throttled state that exerts the pressure reducing action. The pressure becomes equal to or higher than the set pressure α, and the intermediate pressure side opening / closing valve 16a is opened. Thereby, the heat pump cycle 10 is switched to the refrigerant flow path of the gas injection cycle in which the refrigerant flows in the intermediate pressure refrigerant passage 15 as shown in the overall configuration diagram (solid arrow) in FIG. 9C.

  If the intermediate pressure side on / off valve 16a is configured with a differential pressure on / off valve as in the present embodiment, switching between the gas injection cycle and the normal cycle can be realized with a simple configuration and control method.

The present invention is not limited to the above-described embodiment, and can be variously modified as follows without departing from the spirit of the present invention. In the above-mentioned embodiment, although the example which applied the heat pump cycle 10 of this invention to the vehicle air conditioner 1 was demonstrated, application of this invention is not limited to this. For example, the present invention may be applied to a stationary air conditioner, a cold storage container, and the like.
In the above-described embodiment, the heat pump cycle 10 that can realize various operation modes by switching the state of the first variable throttle 13 and the low-stage decompression unit and switching the refrigerant flow path of the heat pump cycle 10 has been described. However, the present invention is not limited to this, and any configuration that can realize at least two operation modes of the heating operation mode and the defrosting heating mode may be used. Of course, providing each operation mode in each operation mode is effective in that the temperature of the blown air can be adjusted appropriately.

  In the above-described embodiment, the example in which the first heating mode and the second heating mode are switched according to the rotation speed of the compressor 11 in the heating operation mode has been described, but switching between the first heating mode and the second heating mode is described. Is not limited to this. That is, the switching between the first heating mode and the second heating mode may be switched to the heating mode that can exhibit a high COP in the first and second heating modes. For example, when the detected value is equal to or lower than a predetermined reference outside air temperature (for example, 0 ° C.) based on the detected value of the outside air sensor, the first heating mode is executed, and the detected value is higher than the reference outside air temperature. In this case, the second heating operation mode may be executed.

  In the above-described embodiment, the air conditioning control device 40 is configured to block either the air passage or the bypass passage 35 of the indoor condenser 12 during each operation mode of the cooling operation mode, the heating operation mode, and the dehumidifying heating operation mode. Although the example which operates the air mix door 34 was demonstrated, the action | operation of the air mix door 34 is not limited to this. That is, the air mix door 34 may open both the air passage and the bypass passage 35 of the indoor condenser 12. And you may adjust the temperature of the ventilation air which blows off into the vehicle interior from the confluence | merging space 36 by adjusting the air volume ratio of the air volume which passes the indoor condenser 12, and the air volume which passes a bypass channel. Such temperature adjustment is effective in that it is easy to finely adjust the temperature of the air blown into the passenger compartment.

  In the above-described embodiment, the example in which the first dehumidifying heating mode is gradually switched from the first dehumidifying heating mode to the fourth dehumidifying heating mode as the target blowing temperature TAO increases in the dehumidifying heating operation mode has been described. Switching to the 4 dehumidifying heating mode is not limited to this. For example, the first dehumidifying and heating mode may be continuously switched from the first dehumidifying and heating mode to the target blowing temperature TAO. That is, as the target blowing temperature TAO increases, the throttle opening of the first variable throttle 13 may be gradually reduced, and the throttle opening of the third variable throttle 22 may be gradually increased. Since the refrigerant pressure (temperature) in the outdoor heat exchanger 20 is adjusted by changing the throttle openings of the first variable throttle 13 and the third variable throttle 22 in this way, the outdoor heat exchanger 20 is automatically turned on. In addition, it is possible to switch from a state of acting as a radiator to a state of acting as an evaporator.

  As described in the above embodiments, in order to achieve fine temperature adjustment of the blown air in each operation mode of the air conditioner 1, it is desirable to provide the intermediate pressure side opening / closing valve 16a in the intermediate pressure refrigerant passage 15. However, the present invention is not limited to this, and each operation mode may be realized with a simple configuration without providing the intermediate pressure side on-off valve 16a.

  In each of the above-described embodiments, the refrigerant discharged from the compressor 11 is used as a refrigerant flow path that passes through the indoor condenser 12 and the refrigerant radiator 52 in the cooling operation mode. However, in the cooling operation mode, the outdoor heat exchanger 20 is used. It is good also as a refrigerant | coolant flow path which can radiate | emit the heat | fever of a refrigerant | coolant to external air and does not let a refrigerant | coolant pass through the indoor condenser 12 or the refrigerant | coolant heat radiator 52.

  In each above-mentioned embodiment, it is set as the structure which arrange | positions the accumulator 24 in the exit side of the indoor evaporator 23 in the heat pump cycle 10, However, It is not limited to this. For example, when the heat pump cycle 10 includes a gas-liquid separator capable of storing excess refrigerant, the accumulator 24 may be eliminated. As a result, the cycle configuration can be simplified.

DESCRIPTION OF SYMBOLS 11 Compressor 11a Suction port 11b Intermediate pressure port 11c Discharge port 12 Indoor condenser 13 1st variable throttle 14 Gas-liquid separator 15 Intermediate pressure refrigerant path 17 2nd variable throttle 20 Outdoor heat exchanger 23 Indoor evaporator

Claims (13)

A compressor (11), an indoor condenser (12), a first variable throttle (13), an outdoor heat exchanger (20), a refrigeration having a main refrigerant circuit in which refrigerant is circulated in the order of the compressor (11). A cycle device;
An air conditioner for a vehicle comprising at least a blower (32) that blows air blown into the vehicle interior and an indoor air conditioning unit (30) that has the indoor condenser (12) that heats the air blown into the vehicle interior,
The indoor condenser (12) heats the air blown in the vehicle interior, and the outdoor heat exchanger (20) dissipates heat and melts frosted ice, so that the vehicle interior is heated while hot gas is heated. An air conditioner for vehicles that allows gas defrosting.   When it is determined that the outdoor heat exchanger (20) is frosted, in order to change the outdoor heat exchanger (20) from heat absorption to heat dissipation, the air flow rate of the blower (32) is reduced, or The vehicle air conditioner according to claim 1, wherein the valve opening of the first variable throttle (13) is adjusted, or one or both of them are performed. In the main refrigerant circuit, a gas-liquid separator (14) is arranged in the order of the indoor condenser (12) and the first variable throttle (13), and further, the gas-liquid separator (14) and the outdoor heat are arranged. Between the exchanger (20), a second variable throttle (17) for introducing a liquid phase or gas phase refrigerant via the gas-liquid separator (14) is disposed,
An intermediate pressure refrigerant passage for introducing an intermediate pressure gas-phase refrigerant that has passed through the gas-liquid separator (14) to an intermediate pressure port (11b) provided in the compressor (11) and joining the refrigerant in the compression process. The vehicle air conditioner according to claim 2, wherein (15) is provided.   When it is determined that the outdoor heat exchanger (20) is frosted, the valve opening of the second variable throttle (17) is further changed to change the outdoor heat exchanger (20) from heat absorption to heat dissipation. The vehicle air conditioner according to claim 3, wherein the air conditioner is adjusted.   The vehicle according to any one of claims 1 to 4, wherein when it is determined that the outdoor heat exchanger (20) has formed frost, the rotational speed of the compressor (11) is increased. Air conditioner.   During the defrosting operation of the outdoor heat exchanger (20), the valve opening of the first variable throttle (13) is made larger than the valve opening of the second variable throttle (17) in order to increase the vehicle interior heating capacity. The intermediate pressure is increased by relatively increasing the intermediate pressure, and the injection flow rate of the intermediate pressure refrigerant from the intermediate pressure port (11b) to the compressor (11) is increased. 2. An air conditioner for a vehicle according to item 1.   The vehicle air conditioner according to any one of claims 3 to 6, wherein an intermediate pressure side on-off valve (16a) is installed in the intermediate pressure refrigerant passage (15).   The vehicle air conditioner according to claim 7, wherein the intermediate pressure side opening / closing valve (16a) opens and closes according to a differential pressure before and after the second variable throttle (17). On the downstream side of the outdoor heat exchanger (20) of the main refrigerant circuit, the cooling on-off valve (16c) is arranged so that the refrigerant flows in the order of the cooling on-off valve (16c), the accumulator (24), and the compressor (11). ), Place the accumulator (24),
Branching from the main refrigerant circuit between the outdoor heat exchanger (20) and the cooling on-off valve (16c), passing through a third variable throttle (22) and an indoor evaporator (23) in this order, A bypass circuit that joins the main refrigerant circuit between the on-off valve (16c) and the accumulator (24);
The vehicle air conditioner according to any one of claims 3 to 8, wherein an intermediate pressure side on-off valve (16a) is installed in the intermediate pressure refrigerant passage (15).   The air conditioner for vehicles according to claim 9, wherein the indoor air conditioning unit (30) further includes the indoor evaporator (23) and an air mix door (34).   The first variable throttle (13) and the second variable throttle (17) are configured to be set to a fully open state and a fully closed state that do not exhibit a pressure reducing action, in addition to a throttle state that exhibits a pressure reducing action. The vehicle air conditioner according to any one of claims 3 to 10, wherein the vehicle air conditioner is provided.   11. The vehicle according to claim 3, wherein a low-pressure side opening / closing valve (16 b) is inserted in parallel with the second variable throttle (17) in the main refrigerant circuit. Air conditioner.   The indoor condenser (12) includes a refrigerant radiator (52) and a heat exchanger (12 ′) for heating, and the refrigerant radiator (52) is connected to the compressor (11) and the heat exchanger in the main refrigerant circuit. The heat exchanger (12 ') is heated between the first variable throttles (13) to a heat medium circulation circuit (50) through which the heat medium circulates. An air conditioner for a vehicle as set forth in claim 1.

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