JP5533207B2 - Heat pump cycle - Google Patents

Description

  The present invention relates to a heat pump cycle that performs a defrosting operation for removing frost attached to a heat exchanger that functions as an evaporator, and for example, used for a vehicle air conditioner that is difficult to secure a heat source for heating from a driving source for traveling. Is preferred.

  Conventionally, Patent Document 1 discloses a vapor compression refrigeration cycle (heat pump cycle) that performs a defrosting operation by melting and removing frost attached to an outdoor heat exchanger that functions as an evaporator for evaporating refrigerant.

  The refrigeration cycle of this Patent Document 1 is applied to a vehicle air conditioner, and is operated in a heating operation mode (heating operation mode) in which the vehicle interior blown air that is a heat exchange target fluid is heated to heat the vehicle interior. The operation in the defrosting operation mode for removing frost attached to the outdoor heat exchanger functioning as an evaporator during the operation in the heating operation mode can be switched.

  Furthermore, the refrigeration cycle of Patent Document 1 includes a compressor that compresses the refrigerant, a first usage-side heat exchanger that flows in the high-temperature refrigerant discharged from the compressor, and the like as a compressor. A two-stage booster compressor provided with an intermediate pressure port (gas injection port) for joining the intermediate pressure gas-phase refrigerant is employed.

  During operation in the heating operation mode, the air blown into the vehicle interior is heated by dissipating heat generated by the high-pressure refrigerant discharged from the compressor to the air blown into the vehicle interior using the first use side heat exchanger. . Further, the flow of the refrigerant flowing out from the first use side heat exchanger is branched, and one of the branched refrigerants is depressurized until it becomes a low-pressure refrigerant, and the depressurized low-pressure refrigerant absorbs heat from the outside air in the outdoor heat exchanger. Has been evaporated.

  On the other hand, the other branched refrigerant is depressurized until it becomes an intermediate pressure refrigerant, heated by exchanging heat with engine cooling water as an external heat source, and the heated intermediate pressure gas-phase refrigerant flows into the intermediate pressure port. . Thereby, in the refrigerating cycle of patent document 1, the heating performance is improved using the waste heat of an engine at the time of heating operation.

  Moreover, when frost formation of the outdoor heat exchanger is detected during the heating operation, the operation in the defrosting operation mode is performed. In this defrosting operation mode, the first usage-side heat exchanger is used as a mere refrigerant passage without dissipating the refrigerant discharged from the compressor in the first usage-side heat exchanger.

  Then, the flow of the high-temperature refrigerant that has flowed out of the first usage-side heat exchanger is branched, the one of the branched refrigerant is depressurized until it becomes a low-pressure refrigerant, and flows into the outdoor heat exchanger. The frost on the outdoor heat exchanger is melted. The other branched refrigerant is also decompressed until it becomes a low-pressure refrigerant, and then heated by an external heat source, and the heat amount of the heated gas-phase refrigerant is dissipated to the vehicle interior blown air by the second usage side heat exchanger. The air blown into the passenger compartment is heated.

  Thereby, in the refrigerating cycle of patent documents 1, heating of a vehicle interior can be continued even at the time of defrosting operation.

JP 2001-30744 A

  However, in the refrigeration cycle of Patent Document 1, the two heat exchangers of the first and second usage-side heat exchangers are indispensable in order to realize heating of the passenger compartment even during the defrosting operation. Therefore, in the defrosting operation mode, it is necessary to switch to a complicated refrigerant flow path that uses the first use side heat exchanger as a simple refrigerant passage.

  In such a cycle configuration, since the driving power of the compressor may increase due to the pressure loss of the refrigerant in the first usage side heat exchanger during the defrosting operation, the coefficient of performance (COP) of the cycle is deteriorated. There is a fear.

  In view of the above points, an object of the present invention is to provide a heat pump cycle that can efficiently heat a heat exchange target fluid even in a defrosting operation mode with a simple configuration.

In order to achieve the above object, in the first aspect of the present invention, the first and second compression mechanisms (11b, 11c) that compress and discharge the refrigerant, and the refrigerant discharged from the second compression mechanism (11c) The use side heat exchanger (13) for exchanging heat with the heat exchange target fluid, the first pressure reducing means (15a) for reducing the pressure of the refrigerant flowing out of the use side heat exchanger (13), and the amount of heat of the external heat source 1 The heating means (14) for heating the refrigerant decompressed by the decompression means (15a), and the gas-liquid of the refrigerant flowing out from the heating means (14) are separated, and the separated gas-phase refrigerant is used as the second compression mechanism. (11c) The gas-liquid separator (16) that flows out to the suction side, the second decompression means (15b) that decompresses the liquid-phase refrigerant separated by the gas-liquid separator (16), and heats the refrigerant and the outside air. Outdoor heat that is exchanged and flows out to the suction side of the first compression mechanism (11b) Refrigerant flow for switching between the exchanger (20), the refrigerant channel in the heating operation mode for heating the heat exchange target fluid, and the refrigerant channel in the defrosting operation mode for melting frost attached to the outdoor heat exchanger (20) Road switching means (12... 18a),
The refrigerant flow switching means (12... 18a) sucks the refrigerant discharged from the first compression mechanism (11b) into the second compression mechanism (11c) and makes the second decompression means (15b) in the heating operation mode. The refrigerant flow reduced in pressure is switched to a refrigerant flow path for flowing into the outdoor heat exchanger (20), and the refrigerant discharged from the first compression mechanism (11b) is transferred to the outdoor heat exchanger (20) in the defrosting operation mode. It is characterized by a heat pump cycle that switches to an inflowing refrigerant flow path.

  According to this, in the heating operation mode, the first compression mechanism (11b) → the second compression mechanism (11c) → the use side heat exchanger (13) → the first pressure reducing means (15a) → the gas-liquid separator (16). → the second decompression means (15b) → the outdoor heat exchanger (20) → the cycle in which the refrigerant circulates in the order of the first compression mechanism (11b) and the second compression mechanism (11c) → the use side heat exchanger (13) → A cycle in which the refrigerant circulates in the order of the first pressure reducing means (15a) → the heating means (14) → the gas-liquid separator (16) → the second compression mechanism (11c) can be configured.

  Therefore, the heat quantity absorbed by the refrigerant from the outside air in the outdoor heat exchanger (20) can be radiated to the heat exchange target fluid and heated in the use side heat exchanger (13). At this time, since the refrigerant heated by the heating means (14) is sucked into the second compression mechanism (11c), the amount of heat supplied from the heating means (14) is used to make the heat exchange target fluid efficient. Can be heated.

  In the defrosting operation mode, the second compression mechanism (11c) → the use side heat exchanger (13) → the first pressure reducing means (15a) → the heating means (14) → the gas-liquid separator (16) → the second compression. A cycle in which the refrigerant circulates in the order of the mechanism (11c) and a cycle in which the refrigerant circulates in the order of the first compression mechanism (11b) → the outdoor heat exchanger (20) → the first compression mechanism (11b) can be configured.

  Therefore, frost attached to the outdoor heat exchanger (20) functioning as an evaporator for evaporating the refrigerant in the heating operation mode can be melted and removed by the heat amount of the refrigerant discharged from the first compression mechanism (11b). At this time, since the refrigerant discharged from the second compression mechanism (11c) flows into the use side heat exchanger (13), the heat exchange target fluid can be heated by the amount of heat supplied from the heating means (14).

  That is, according to the heat pump cycle described in the present claim, the refrigerant discharged from the second compression mechanism (11c) is directly flowed into the use side heat exchanger (13) even in the defrosting operation mode. Therefore, the pressure loss of the refrigerant is not increased unnecessarily. As a result, it is possible to provide a heat pump cycle capable of efficiently heating the heat exchange target fluid even in the defrosting operation mode with a simple configuration that does not need to provide a plurality of use side heat exchangers (13). it can.

As in the invention according to claim 2 , in the heat pump cycle according to claim 1 , the refrigerant flow switching means connects the discharge side of the first compression mechanism (11b) and the suction side of the second compression mechanism (11c). The refrigerant flow path and the three-way valve (12) for switching the refrigerant flow path connecting the discharge side of the first compression mechanism (11b) and the inlet side of the outdoor heat exchanger (20) may be configured. Thereby, a refrigerant | coolant flow path switching means can be comprised easily.

In the heat pump cycle according to claim 1 or 2 , as in the invention according to claim 3 , the heat pump cycle is applied to a vehicle air conditioner, and the heat exchange target fluid is blown into the vehicle interior. It is indoor blown air, and the external heat source may be cooling water that cools the internal combustion engine (41) that outputs driving force for traveling the vehicle.

Further, as in the invention described in claim 4 , in the heat pump cycle described in claim 3 , the heat pump cycle may further include a flow rate adjusting means (42a) for adjusting the flow rate of the cooling water flowing into the heating means (14). . Thereby, the heating capability of a heating means (14) can be adjusted according to the cooling water temperature of an internal combustion engine (41).

Further, as in the invention according to claim 5 , in the heat pump cycle according to any one of claims 1 to 4 , the second compression mechanism (11c) discharge refrigerant and heat in the use side heat exchanger (13). A heat exchange amount adjusting means (34) for adjusting the heat exchange amount with the exchange target fluid may be provided.

According to this, since the heat quantity of the refrigerant discharged from the second compression mechanism (11c) can be supplied to the heating means (14), for example, as an external heat source as in claim 3 or 4 , the internal combustion engine (41) When cooling water is used to cool the engine, the heating means (14) can heat the cooling water to promote warm-up of the internal combustion engine (41).

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

It is a whole block diagram which shows the refrigerant | coolant flow path at the time of the normal heating operation mode of the heat pump cycle of 1st Embodiment. It is a whole block diagram which shows the refrigerant | coolant flow path at the time of the defrost operation mode of the heat pump cycle of 1st Embodiment. It is a whole block diagram which shows the refrigerant | coolant flow path at the time of warming-up heating operation mode of the heat pump cycle of 1st Embodiment. It is a whole block diagram which shows the refrigerant | coolant flow path at the time of the warming-up promotion operation mode of the heat pump cycle of 1st Embodiment. It is a whole block diagram which shows the refrigerant | coolant flow path at the time of the air_conditionaing | cooling operation mode and dehumidification operation mode of the heat pump cycle of 1st Embodiment. It is a graph which shows the operating state of the refrigerant | coolant flow path switching means in each operation mode of 1st Embodiment. It is a flowchart of the control routine which an air-conditioning control apparatus performs at the time of the heating operation mode of 1st Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant at the time of the normal heating operation mode of the heat pump cycle of 1st Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant at the time of the dehumidification operation mode of the heat pump cycle of 1st Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant at the time of warming-up heating operation mode of the heat pump cycle of 1st Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant at the time of the warming-up promotion operation mode of the heat pump cycle of 1st Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant at the time of the cooling operation mode of the heat pump cycle of 1st Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant at the time of the dehumidification operation mode of the heat pump cycle of 1st Embodiment. It is a whole block diagram which shows the refrigerant | coolant flow path at the time of the normal heating operation mode of the heat pump cycle of 2nd Embodiment. It is a graph which shows the operating state of the refrigerant | coolant flow path switching means in each operation mode of 2nd Embodiment. It is a Mollier diagram which shows the state of the refrigerant | coolant at the time of the normal heating operation mode of the heat pump cycle of 2nd Embodiment. It is a whole block diagram which shows the refrigerant | coolant flow path at the time of the cooling operation mode and defrost operation mode of the heat pump cycle of other embodiment.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the heat pump cycle 10 of the present invention is applied to a vehicle air conditioner 1 for a so-called hybrid vehicle that obtains driving force for vehicle travel from an internal combustion engine (engine) 41 and a travel electric motor. The heat pump cycle 10 functions in the vehicle air conditioner 1 to heat or cool vehicle interior air blown into the vehicle interior that is the air-conditioning target space.

  Therefore, the heat pump cycle 10 of the present embodiment cools the refrigerant flow path in the heating operation mode (heating operation mode) in which the vehicle interior air that is the heat exchange target fluid is heated to heat the vehicle interior, and the vehicle interior air. Thus, the refrigerant flow path in the cooling operation mode (cooling operation mode) for cooling the vehicle interior can be switched.

  Furthermore, in the heat pump cycle 10, various operation modes such as a refrigerant flow path in a defrosting operation mode that melts and removes frost attached to the outdoor heat exchanger 20 that functions as an evaporator that evaporates the refrigerant during operation in the heating operation mode. It is possible to switch to the refrigerant flow path. In addition, in the whole block diagram of the heat pump cycle 10 of FIGS. 1-5, the flow of the refrigerant | coolant in each operation mode is shown with the solid line arrow.

  Moreover, in the heat pump cycle 10 of this embodiment, the normal CFC-type refrigerant | coolant is employ | adopted as a refrigerant | coolant, and the subcritical refrigeration cycle in which the high pressure side refrigerant | coolant pressure does not exceed the critical pressure of a refrigerant | coolant is comprised. 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.

  First, the compressor 11 is arrange | positioned in an engine room, suck | inhales a refrigerant | coolant in the heat pump cycle 10, is compressed, and is discharged. More specifically, in this embodiment, as the compressor 11, two fixed capacity type first and second compression mechanisms 11b and 11c are accommodated in the same housing 11a, and both the compression mechanisms 11b and 11c are accommodated. A two-stage booster type electric compressor driven by a common electric motor is employed.

  As the first and second compression mechanisms 11b and 11c, various compression mechanisms such as a scroll compression mechanism and a vane compression mechanism can be employed. Further, the electric motor is one whose rotational speed is controlled by a control signal output from an air conditioning control device 50 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, the electric motor constitutes the discharge capacity changing means of the compressor 11.

  Furthermore, in the housing 11a of the compressor 11 of the present embodiment, there is an electric three-way valve 12 that constitutes a refrigerant flow path switching means for switching between the refrigerant flow path in the heating operation mode and the refrigerant flow path in the defrosting operation mode. Has been placed.

  Specifically, the three-way valve 12 includes a refrigerant flow path that connects the discharge port of the first compression mechanism 11b and the suction port of the second compression mechanism 11c inside the housing 11a, and the discharge port of the first compression mechanism 11b and the outside of the housing 11a. The refrigerant flow path connecting the discharge outlet (specifically, the bypass port 11g) to be discharged is switched. Further, the operation of the three-way valve 12 is controlled by a control voltage output from the air conditioning controller 50.

  Further, the housing 11a of the compressor 11 has a suction port 11d for sucking low-pressure refrigerant, an intermediate-pressure port 11e for flowing intermediate-pressure refrigerant, a discharge port 11f for discharging high-pressure refrigerant, and a refrigerant from the three-way valve 12 to the outside of the housing 11a. A bypass port 11g for discharging is provided. These ports 11d to 11g are connected to the first and second compression mechanisms 11b and 11c and the three-way valve 12 inside the housing 11a.

  More specifically, the suction port 11d is connected to the suction port of the first compression mechanism 11b, and the intermediate pressure port 11e communicates with one refrigerant outlet of the three-way valve 12 and the suction port of the second compression mechanism 11c. The discharge port 11f is connected to the discharge port of the second compression mechanism 11c, and the bypass port 11g is connected to the other refrigerant outlet of the three-way valve 12.

  Therefore, the first compression mechanism 11b sucks and compresses the low-pressure refrigerant sucked from the suction port 11d and discharges it to the refrigerant inlet side of the three-way valve 12.

  On the other hand, when the three-way valve 12 connects the discharge port of the first compression mechanism 11b and the suction port of the second compression mechanism 11c, the second compression mechanism 11c sucks from the refrigerant discharged from the first compression mechanism 11b and the intermediate pressure port 11e. The intermediate pressure refrigerant mixed with the refrigerant is sucked and compressed and discharged from the discharge port 11f. When the three-way valve 12 connects the discharge port of the first compression mechanism 11b and the bypass port 11g, the refrigerant sucked from the intermediate pressure port 11e is sucked and compressed, and discharged from the discharge port 11f.

  The refrigerant inlet side of the indoor condenser 13 as a use side heat exchanger is connected to the discharge port (specifically, the discharge port 11f) of the compressor 11 as a whole. The indoor condenser 13 is disposed in the casing 31 of the indoor air conditioning unit 30 of the vehicle air conditioner 1, and heats the high-temperature and high-pressure refrigerant that circulates in the interior and the air blown into the vehicle interior after passing through the indoor evaporator 21 described later. It is a heat exchanger for heating to be exchanged. The details of the indoor air conditioning unit 30 will be described later.

  A first electric expansion valve 15 a is connected to the refrigerant outlet side of the indoor condenser 13 as first decompression means for depressurizing the refrigerant flowing out of the indoor condenser 13. The first electric expansion valve 15 a is a variable throttle mechanism that decompresses and expands the refrigerant flowing out of the indoor condenser 13.

  More specifically, the first electric expansion valve 15a includes a valve body configured to be able to change the throttle opening degree and an electric actuator including a stepping motor that changes the opening degree of the valve body. Has been. The operation of the first electric expansion valve 15a is controlled by a control signal output from the air conditioning control device 50. Further, the first electric expansion valve 15a functions as a simple refrigerant passage without exhibiting a refrigerant pressure reducing action when the throttle opening of the valve body is fully opened.

  The inlet side of the refrigerant side flow path 14a of the water-refrigerant heat exchanger 14 is connected to the refrigerant outlet side of the first electric expansion valve 15a. The water-refrigerant heat exchanger 14 performs cooling by exchanging heat between the refrigerant flowing through the refrigerant side flow path 14a and the cooling water of the engine 41 flowing through the cooling water side flow path 14b at least in a normal heating operation mode described later. It functions as a heating means for heating the refrigerant by the amount of heat of water.

  Therefore, the external heat source of the heating means of this embodiment is the cooling water for the engine 41. The details of the cooling water circuit 40 that circulates the cooling water flowing through the cooling water side passage 14b will be described later.

  The specific configuration of the water-refrigerant heat exchanger 14 is a double-pipe heat exchange in which an inner tube that forms the refrigerant-side channel 14a is arranged inside an outer tube that forms the cooling-water channel 14b. Can be used. Of course, the refrigerant side flow path 14a may be an inner pipe and the cooling water side flow path 14b may be an outer pipe. Further, a configuration may be adopted in which the refrigerant pipes constituting the refrigerant side flow path 14a and the cooling water side flow path 14b are brazed and joined to exchange heat.

  In addition, as a specific configuration of the water-refrigerant heat exchanger 14, a meandering tube or a plurality of tubes for circulating the refrigerant is adopted as the refrigerant side flow path 14 a, and the cooling water side flow is provided between adjacent tubes. A heat exchanger configuration in which a path 14b is formed and further provided with corrugated corrugated fins or plate-like plate fins that promote heat exchange between the refrigerant and the cooling water can be employed.

  The inlet side of the gas-liquid separator 16 is connected to the outlet side of the refrigerant side flow path 14 a of the water-refrigerant heat exchanger 14. This gas-liquid separator 16 separates the gas-liquid refrigerant flowing out of the water-refrigerant heat exchanger 14. Further, the gas-phase refrigerant outlet of the gas-liquid separator 16 is connected to the intermediate pressure port 11e of the compressor 11, and the liquid-phase refrigerant outlet is connected to one refrigerant inlet of the first three-way joint 17a.

  The first three-way joint 17a has three inlets and outlets communicating with each other, two of the three inlets and outlets being refrigerant inlets and one being a refrigerant outlet. Such a three-way joint may be constituted by joining various pipes, or may be constituted by providing a plurality of refrigerant passages in a metal block or a resin block.

  A first on-off valve 18a for opening and closing the refrigerant pipe is disposed in the refrigerant pipe from the gas-phase refrigerant outlet of the gas-liquid separator 16 to the intermediate pressure port 11e of the compressor 11. The first on-off valve 18 a is an electromagnetic valve whose operation is controlled by a control voltage output from the air conditioning control device 50.

  Further, the first on-off valve 18 a functions to switch the refrigerant flow path of the heat pump cycle 10 by opening and closing the refrigerant pipe from the gas-phase refrigerant outlet of the gas-liquid separator 16 to the intermediate pressure port 11 e of the compressor 11. . Therefore, the 1st on-off valve 18a comprises the refrigerant | coolant flow path switching means of this embodiment with the three-way valve 12 mentioned above.

  A second decompression that decompresses the liquid-phase refrigerant separated by the gas-liquid separator 16 is provided in a refrigerant pipe extending from the liquid-phase refrigerant outlet of the gas-liquid separator 16 to the refrigerant inlet of the first three-way joint 17a of the compressor 11. A second electric expansion valve 15b as a means is arranged. The basic configuration of the second electric expansion valve 15b is the same as that of the first electric expansion valve 15a.

  Further, the second electric expansion valve 15b is a refrigerant pipe that extends from the liquid-phase refrigerant outlet of the gas-liquid separator 16 to the refrigerant inlet side of the first three-way joint 17a of the compressor 11 with its throttle opening fully closed. The flow of the refrigerant can be cut off. Thereby, the 2nd electric expansion valve 15b fulfill | performs the function which switches the refrigerant | coolant flow path of the heat pump cycle 10. FIG. Therefore, the second electric expansion valve 15b of the present embodiment also has a function as a refrigerant flow path switching unit.

  The other refrigerant inlet of the first three-way joint 17 a is connected to the bypass port 11 g of the compressor 11 via the bypass passage 19. Furthermore, a check valve 19a that allows only a refrigerant to flow from the bypass port 11g side toward the first three-way joint 17a side is disposed in the bypass passage 19.

  The bypass passage 19 and the check valve 19 a are configured to cause a predetermined pressure loss in the refrigerant flowing through the bypass passage 19. Specifically, at least one of the refrigerant passage area, the length, the bent shape of the bypass passage 19 and the refrigerant passage area when the check valve 19a is opened is set to cause a predetermined pressure loss in the refrigerant. Has been.

  An outdoor heat exchanger 20 is connected to the refrigerant outlet of the first three-way joint 17a to exchange heat between the refrigerant flowing through the inside and the outside air blown from the blower fan 20a. The outdoor heat exchanger 20 is disposed in the engine room and functions as an evaporator that evaporates the low-pressure refrigerant and exerts an endothermic effect when operating in the heating operation mode, and when operating in the cooling operation mode. Is a heat exchanger that functions as a radiator that dissipates high-pressure refrigerant.

  The blower fan 20a is an electric blower in which the operation rate, that is, the rotation speed (the amount of blown air) is controlled by the control voltage output from the air conditioning control device 50.

  A refrigerant inflow port of the second three-way joint 17b is connected to the outlet side of the outdoor heat exchanger 20. The basic configuration of the second three-way joint 17b is the same as that of the first three-way joint 17a. In the second three-way joint 17b, one of the three inlets and outlets is a refrigerant inlet and two of the three inlets are the refrigerant outlet with respect to the first three-way joint 17a.

  A refrigerant inlet side of the indoor evaporator 21 is connected to one refrigerant outlet of the second three-way joint 17b via a third electric expansion valve 15c. The indoor evaporator 21 is arranged in the casing 31 of the indoor air conditioning unit 30 on the upstream side of the air flow with respect to the indoor condenser 13, and exchanges heat between the refrigerant circulating in the interior and the air blown into the vehicle interior, It is a heat exchanger for cooling which cools vehicle interior blowing air.

  The third electric expansion valve 15c is a pressure reducing means for reducing the pressure of the refrigerant flowing out from one refrigerant outlet of the second three-way joint 17b, and the basic configuration thereof is the first and second electric expansion valves 15a. , 15b. Further, the third electric expansion valve 15c fully closes the throttle opening, and blocks the flow of the refrigerant in the refrigerant pipe extending from one refrigerant outlet of the second three-way joint 17b to the refrigerant inlet side of the indoor evaporator 21. can do.

  Thereby, the 3rd electric expansion valve 15c fulfill | performs the function which switches the refrigerant | coolant flow path of the heat pump cycle 10. FIG. Therefore, the third electric expansion valve 15c of this embodiment also has a function as a refrigerant flow path switching unit.

  One refrigerant inlet of the third three-way joint 17c is connected to the other refrigerant outlet of the second three-way joint 17b via a second on-off valve 18b. The basic configuration of the third three-way joint 17c is the same as that of the first and second three-way joints 17a and 17b. In the third three-way joint 17c, as in the first three-way joint 17a, two of the three inlets and outlets are refrigerant inlets and one is a refrigerant outlet.

  Further, the basic configuration of the second on-off valve 18b is the same as that of the first on-off valve 18a. The 2nd on-off valve 18b is a function which switches the refrigerant | coolant flow path of the heat pump cycle 10 by opening and closing the refrigerant | coolant piping from the other refrigerant | coolant outflow port of the 2nd three-way joint 17b to one refrigerant | coolant inflow port of the 3rd three-way joint 17c. Fulfill.

  Accordingly, the second on-off valve 18b, together with the above-described three-way valve 12, the first on-off valve 18a, the second electric expansion valve 15b, and the third electric expansion valve 15c, constitutes the refrigerant flow switching means of the present embodiment. ing.

  The refrigerant outlet side of the indoor evaporator 21 is connected to the other refrigerant inlet of the third three-way joint 17c, and the refrigerant inlet side of the accumulator 22 is connected to the refrigerant outlet of the third three-way joint 17c. The accumulator 22 is a low-pressure side gas-liquid separator that separates the gas-liquid refrigerant flowing into the accumulator 22 and stores excess refrigerant. The suction port 11d of the compressor 11, that is, the suction side of the first compression mechanism 11b is connected to the gas-phase refrigerant outlet of the accumulator 22.

  Next, the indoor air conditioning unit 30 will be described. The indoor air-conditioning unit 30 is disposed inside the instrument panel (instrument panel) at the foremost part of the vehicle interior, and a blower 32, the above-described indoor condenser 13, the indoor evaporator 21 and the like in a casing 31 that forms an outer shell thereof. Is housed.

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

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

  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 50.

  On the downstream side of the air flow of the blower 32, the indoor evaporator 21 and the indoor condenser 13 are arranged in this order with respect to the flow of the air blown into the vehicle interior. In other words, the indoor evaporator 21 is disposed upstream of the indoor condenser 13 in the flow direction of the vehicle interior blown air.

  Further, on the downstream side of the air flow of the indoor evaporator 21 and on the upstream side of the air flow of the indoor condenser 13, the ratio of the amount of air passing through the indoor condenser 13 in the blown air after passing through the indoor evaporator 21. An air mix door 34 for adjusting the air pressure is disposed. Further, on the downstream side of the air flow of the indoor condenser 13, the blown air heated by exchanging heat with the refrigerant in the indoor condenser 13 and the blown air not heated while bypassing the indoor condenser 13 are mixed. A mixing space 35 is provided.

  An air outlet that blows the conditioned air mixed in the mixing space 35 into the passenger compartment, which is a space to be cooled, is disposed at the most downstream portion of the air flow of the casing 31. Specifically, as this air outlet, there are a face air outlet that blows air-conditioned air toward the upper body of the passenger in the vehicle interior, a foot air outlet that blows air-conditioned air toward the feet of the passenger, and the inner surface of the front window glass of the vehicle A defroster outlet (both not shown) is provided to blow air-conditioned air toward the front.

  Therefore, the temperature of the conditioned air mixed in the mixing space 35 is adjusted by adjusting the ratio of the air volume that the air mix door 34 passes through the indoor condenser 13, and the temperature of the conditioned air blown out from each outlet is adjusted. Is adjusted. That is, the air mix door 34 constitutes a temperature adjusting means for adjusting the temperature of the conditioned air blown into the vehicle interior.

  In other words, the air mix door 34 determines the amount of heat exchange between the refrigerant discharged from the compressor 11 (specifically, the second compression mechanism 11c) and the air blown into the vehicle interior in the indoor condenser 13 constituting the use side heat exchanger. It functions as a heat exchange amount adjusting means to adjust. 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 control device 50.

  Further, on the upstream side of the air flow of the face outlet, the foot outlet, and the defroster outlet, a face door for adjusting the opening area of the face outlet, a foot door for adjusting the opening area of the foot outlet, and the defroster outlet, respectively. A defroster door (none of which is shown) for adjusting the opening area is arranged.

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

  Next, the cooling water circuit 40 that circulates the cooling water flowing through the cooling water side flow path 14b of the water-refrigerant heat exchanger 14 will be described. The cooling water circuit 40 circulates cooling water (for example, an ethylene glycol aqueous solution) for cooling the engine 41. The cooling water circuit 40 includes first and second cooling water pumps 42a and 42b, a radiator 43, and the like. Has been.

  The first cooling water pump 42 a is an electric pump that pumps cooling water to the cooling water side flow path 14 b of the water-refrigerant heat exchanger 14, and the rotation speed (flow rate) is controlled by a control signal output from the air conditioning control device 50. ) Is controlled. Therefore, the 1st cooling water pump 42a fulfill | performs the function as a flow volume adjustment means which adjusts the flow volume of the cooling water which flows in into the water-refrigerant heat exchanger 14 as a heating means.

  That is, when the temperature of the cooling water is sufficiently increased, the refrigerant heating capacity in the water-refrigerant heat exchanger 14 can be increased by increasing the flow rate of the first cooling water pump 42a. The refrigerant heating capacity in the water-refrigerant heat exchanger 14 can be reduced by reducing the flow rate of the one cooling water pump 42a. Furthermore, if the operation of the first cooling water pump 42a is stopped, the water-refrigerant heat exchanger 14 can be prevented from exhibiting the refrigerant heating ability.

  The second cooling water pump 42 b pumps the cooling water to the radiator 43, and an electric pump or a mechanical pump that obtains rotational driving force from the drive shaft of the engine 41 can be employed. The radiator 43 is a heat exchanger for heat radiation that cools the cooling water by exchanging heat between the cooling water and the outdoor air. That is, the radiator 43 radiates the waste heat of the engine 41 that has absorbed heat when the coolant flows through the engine 41 to the atmosphere.

  Therefore, in the cooling water circuit 40 of the present embodiment, the first and second cooling water pumps 42a and 42b are operated, so that the first cooling water pump 42a → water-refrigerant as shown by the broken line arrows in FIG. The cooling water can be circulated in the order of the cooling water side flow path 14b of the heat exchanger 14 → the engine 41 → the first cooling water pump 42a. Further, in parallel with the circulating flow of the cooling water, the cooling water can be circulated in the order of the second cooling water pump 42b → the radiator 43 → the engine 41 → the second cooling water pump 42b.

  Further, in the cooling water circuit 40, when the temperature of the bypass circuit that bypasses the radiator 43 and circulates the cooling water and the temperature of the cooling water is equal to or lower than a predetermined value (90 ° C. in the present embodiment), the cooling water flows to the bypass circuit side. A thermostat valve (both not shown) is arranged. As a result, the temperature of the engine 41 itself is lowered, and the occurrence of friction loss due to the increase in the viscosity of the engine oil and the malfunction of the exhaust gas purifying catalyst due to the temperature decrease of the exhaust gas are suppressed.

  Next, the electric control unit of this embodiment will be described. The air conditioning control device 50 is composed of a well-known microcomputer including a CPU, ROM, RAM, and its peripheral circuits, and performs various calculations and processing based on 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 11, 12, 15a to 15c, 18a, 18b, 32 and the like is controlled.

  Further, on the input side of the air-conditioning control device 50, an inside air sensor that detects the temperature inside the vehicle, an outside air sensor 51 that detects the outside air temperature, a solar radiation sensor that detects the amount of solar radiation in the vehicle interior, and the temperature of the air blown from the indoor evaporator 21 ( An evaporator temperature sensor for detecting the evaporator temperature), an outlet refrigerant temperature sensor 52 for detecting the refrigerant temperature on the outlet side of the outdoor heat exchanger 20, a cooling water temperature sensor for detecting the temperature of the cooling water flowing out from the engine 41, and a compressor 11 Various air conditioning control sensors such as a discharge refrigerant temperature sensor for detecting the discharge refrigerant temperature are connected.

  Further, 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 50, and operation signals from various air conditioning operation switches provided on the operation panel are input. The As various air conditioning operation switches provided on the operation panel, there are provided an operation switch of a vehicle air conditioner, a vehicle interior temperature setting switch for setting the vehicle interior temperature, an operation mode selection switch, and the like.

  The air conditioning control device 50 is configured integrally with control means for controlling the electric motor of the compressor 11, the three-way valve 12, and the like, and controls these operations. In this embodiment, the air conditioning control device 50 is used. Among them, the configuration (hardware and software) for controlling the operation of the various devices 12, 15b, 15c, 18a, and 18b constituting the refrigerant flow path switching means constitutes the refrigerant flow path control means.

  1 to 5 illustrate only the connection relationship between the air-conditioning control device 50 and the outside air sensor 51 and the connection relationship between the air-conditioning control device 50 and the outlet refrigerant temperature sensor 52 for the sake of clarity. The connection relationship with various air conditioning control devices connected to the output side is not shown.

  Next, the operation of the vehicle air conditioner 1 according to the present embodiment having the above-described configuration will be described with reference to FIGS. FIG. 6 is a chart showing the operating state of the refrigerant flow path switching means of the present embodiment, and FIG. 7 is a flowchart of a control routine executed by the air conditioning control device 50 in the heating operation mode. These are Mollier diagrams which show the state of the refrigerant | coolant of the heat pump cycle 10 in each operation mode.

  In the vehicle air conditioner 1 of this embodiment, in addition to the heating operation mode, the defrosting operation mode, and the cooling operation mode described above, it is possible to switch to the warm-up promotion operation mode, the dehumidification operation mode, and the like. The operation in each operation mode will be described below.

(A) Heating operation mode and defrosting operation mode In the heating operation mode of the present embodiment, the vehicle interior can usually be heated using both outside air and waste heat of the engine 41 as heat sources.

  However, when the temperature of the cooling water is low, such as when the engine 41 is warming up, heating the vehicle interior using the waste heat of the engine 41 as a heat source prevents the engine 41 from warming up. Therefore, during the warm-up of the engine 41, the operation is switched to the operation in the air endothermic heating operation mode (hereinafter referred to as the warm-up heating operation mode) in which the vehicle interior is heated using only outside air as a heat source.

  In addition, if frost formation occurs in the outdoor heat exchanger 20 that functions as an evaporator that evaporates the refrigerant during operation in the heating operation mode, the vehicle interior cannot be heated using outside air as a heat source. Therefore, when frost formation occurs in the outdoor heat exchanger 20, the operation is switched to the operation in the defrosting operation mode.

  Specifically, the operation in the heating operation mode is started when the heating operation mode is selected by the selection switch in a state where the operation switch of the vehicle air conditioner 1 of the operation panel is turned on. When the operation in the heating operation mode is started, the air conditioning control device 50 executes a control routine shown in the flowchart of FIG. This control routine is executed as a subroutine of a main routine executed by the air conditioning control device 50.

  First, in step S1, it is determined whether or not the engine 41 is warming up. Specifically, in step S1, if the temperature of the cooling water detected by the cooling water temperature sensor is equal to or lower than a predetermined reference cooling water temperature, it is determined that the engine 41 is warming up.

  If it is determined in step S1 that the engine 41 is warming up, the process proceeds to step S2, the warming-up heating operation mode is selected, and the process proceeds to step S6. If it is determined in step S1 that the engine 41 is not warming up, the process proceeds to step S3, and the normal heating operation mode is selected.

  Furthermore, in the following step S4, it is determined whether or not it is necessary to perform a defrosting operation. Specifically, in step S4, the outdoor heat exchanger 20 outlet-side refrigerant temperature is 0 ° C. or less, and a temperature difference obtained by subtracting the outdoor heat exchanger 20 outlet-side refrigerant temperature from the outside air temperature is a predetermined reference. If it is equal to or greater than the temperature difference, it is determined that it is necessary to perform a defrosting operation.

  If it determines with it being necessary to perform a defrost operation in step S4, it will progress to step S5 and a defrost operation mode will be selected. Then, the process proceeds to step S6. If it is determined in step S4 that it is not necessary to perform the defrosting operation, the process proceeds to step S6.

  In step S6, it is determined whether or not a stop signal for the heating operation mode is output from the operation panel. And in step S6, if it determines with the stop signal of heating operation mode being output, control of heating operation mode will be complete | finished. If it is determined in step S6 that the heating operation mode stop signal has not been output, the process returns to step S1 after a predetermined control period has elapsed.

  Next, a normal heating operation mode, that is, a heating operation mode in which the vehicle interior is heated using both outside air and waste heat of the engine 41 as heat sources will be described.

  In this normal heating operation mode, the air-conditioning control device 50 includes the first electric expansion valve 15a and the three-way valve 12, the second and third electric expansion valves 15b, 15c, first, The operating states of the second on-off valves 18a and 18b are switched as shown in FIG. 6, and the first cooling water pump 42a is further operated to pressure-feed a predetermined flow rate of cooling water.

  Specifically, the three-way valve 12 is switched to a refrigerant flow path connecting the discharge side of the first compression mechanism 11b and the suction side of the second compression mechanism 11c, and the first and second electric expansion valves 15a and 15b are depressurized. The throttle state is set, the third electric expansion valve 15c is fully closed, and the first and second on-off valves 18a and 18b are opened. Thereby, the heat pump cycle 10 is switched to the refrigerant | coolant flow path through which a refrigerant | coolant flows as shown by the solid line arrow of FIG.

  With this refrigerant flow path configuration, the air conditioning control device 50 reads the detection signal of the above-described air conditioning control sensor group and the operation signal of the operation panel. And the target blowing temperature TAO which is the target temperature of the air which blows off into a vehicle interior is calculated based on the value of a detection signal and an operation signal. Furthermore, based on the calculated 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 50 are 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 21 is determined based on the target outlet temperature TAO with reference to a control map stored in the air conditioning controller 50 in advance.

  And based on the deviation of this target evaporator blowing temperature TEO and the blowing air temperature from the indoor evaporator 21 detected by the evaporator temperature sensor, the blowing air temperature from the indoor evaporator 21 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.

  For the control signal output to the servo motor of the air mix door 34, the target blowing temperature TAO, the blowing air temperature from the indoor evaporator 21, the discharge refrigerant temperature detected by the discharge refrigerant temperature sensor, and the like are used. Thus, the temperature of the air blown into the passenger compartment is determined so as to be a desired temperature for the passenger set by the passenger compartment temperature setting switch.

  Note that, in the normal heating operation mode, the warming-up heating operation mode, and the defrosting operation mode, the air mix door 34 is configured so that the total air volume of the vehicle interior air blown from the blower 32 passes through the indoor condenser 13. The degree of opening may be controlled.

  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 same manner in the other operation modes.

In the heat pump cycle 10 of the normal heating operation mode, as shown in the Mollier diagram of FIG. 8, the inflow high pressure refrigerant discharged from the discharge port 11f of the compressor 11 (a _8-point in FIG. 8) into the indoor condenser 13 To do. The refrigerant flowing into the indoor condenser 13, the blower 32 is blown from the radiating heat by the passenger compartment blown air and the heat exchanger passing through the interior evaporator 21 (a _8-point in FIG. 8 → b ₈ points). Thereby, vehicle interior blowing air is heated.

The high-pressure refrigerant flowing from the indoor condenser 13, and flows into the first electric expansion valve 15a, it is decompressed and expanded until the intermediate-pressure refrigerant (b ₈ points in Fig. 8 → c ₈ points). The intermediate pressure refrigerant decompressed and expanded by the first electric expansion valve 15a flows into the refrigerant side flow path 14a of the water-refrigerant heat exchanger 14 and exchanges heat with the cooling water flowing through the cooling water side flow path 14b. Heated (c ₈ point → d ₈ point in FIG. 8).

The refrigerant flowing out of the water-refrigerant heat exchanger 14 is gas-liquid separated by the gas-liquid separator 16 (d ₈ point → e ₈ point and d ₈ point → f ₈ point in FIG. ₈ ). The gas-phase refrigerant separated by the gas-liquid separator 16 flows into the compressor 11 from the intermediate pressure port 11e of the compressor 11 because the first on-off valve 18a is open, The refrigerant merges with the refrigerant discharged from the first compression mechanism 11b (point a1 _{8 in} FIG. 8) (point a2 _{8 in} FIG. 8) and is sucked into the second compression mechanism 11c.

On the other hand, the liquid phase refrigerant separated by the gas-liquid separator 16 flows into the second electric expansion valve 15b, is decompressed and expanded until the low-pressure refrigerant (f ₈ points in Fig. 8 → g ₈ points). At this time, the throttle opening degree of the first and second electric expansion valves 15a and 15b is determined so that the pressure of the intermediate pressure refrigerant is the product of the pressures of the high pressure refrigerant and the low pressure refrigerant in order to bring the coefficient of performance (COP) of the cycle close to the maximum value. It is desirable to adjust so as to be about the square root of.

The vacuum expanded low-pressure refrigerant at the second electric expansion valve 15b (g ₈ points in Fig. 8) via the first three-way joint 17a, and flows into the outdoor heat exchanger 20. The low-pressure refrigerant that has flowed into the outdoor heat exchanger 20 absorbs heat from the outside air and evaporates (g ₈ point → h ₈ point in FIG. 8).

The refrigerant that has flowed out of the outdoor heat exchanger 20 has the third electric expansion valve 15c fully closed, and the second on-off valve 18b is open, so that the second and third three-way joints 17b and 17c are connected. Then, it flows into the accumulator 22 and is separated into gas and liquid. Then, (a0 ₈ points in Fig. 8) the gas-phase refrigerant separated by the accumulator 22 is again compressed is sucked from the suction port 11d of the compressor 11.

  As described above, in the normal heating operation mode, the air blown into the vehicle interior is heated by the amount of heat of the refrigerant discharged from the compressor 11 by the indoor condenser 13, and the vehicle interior can be heated.

  At this time, the gas-liquid of the refrigerant heated by the water-refrigerant heat exchanger 14 is separated, and the separated liquid-phase refrigerant is absorbed by the outdoor heat exchanger 20 to absorb heat from the outside air and separated. The gas-phase refrigerant thus taken is sucked into the compressor 11 (specifically, the second compression mechanism 11c) from the intermediate pressure port 11e.

  Therefore, in the normal heating operation mode, not only the amount of heat absorbed by the refrigerant from the outside air in the outdoor heat exchanger 20, but also the amount of heat of the cooling water, that is, the waste heat of the engine 41, is used to efficiently convert the air blown into the vehicle interior. Can be heated.

  Next, the defrosting operation mode will be described.

  In this defrosting operation mode, as shown in FIG. 6, the air-conditioning control device 50 switches the three-way valve 12 to the refrigerant flow path connecting the discharge side of the first compression mechanism 11b and the bypass port 11g, and the first electric expansion valve The refrigerant is in a throttled state 15a, the second and third electric expansion valves 15b and 15c are fully closed, the first and second on-off valves 18a and 18b are opened, and the first cooling water pump 42a is predetermined. Operate to pump a predetermined amount of cooling water.

Thereby, the heat pump cycle 10 is switched to the refrigerant | coolant flow path through which a refrigerant | coolant flows as shown to the solid line arrow of FIG. Therefore, in the heat pump cycle 10 in the defrosting operation mode, as shown in the Mollier diagram of FIG. 9, the high-pressure refrigerant (point a _{9 in} FIG. 9) discharged from the discharge port 11 f of the compressor 11 is converted into the indoor condenser 13. by radiating flows into (a ₉ points in FIG. 9 → b ₉ points), the vehicle compartment blown air is heated.

Further, refrigerant flowing from the indoor condenser 13, similarly to the normal heating operation mode is decompressed and expanded by the first electric expansion valve 15a (b ₉ points in FIG. 9 → c ₉ points), water - refrigerant heat Heated by the exchanger 14 (c ₉ point → d ₉ point in FIG. 9), and further gas-liquid separated by the gas-liquid separator 16. Gas-phase refrigerant separated by the gas-liquid separator 16, the intermediate pressure port 11e of the compressor 11 is sucked into the second compression mechanism 11c (a2 ₉ points in FIG. 9), it is compressed again.

  At this time, since the three-way valve 12 is switched to the refrigerant flow path connecting the discharge side of the first compression mechanism 11b and the bypass port 11g, the refrigerant flowing into the compressor 11 from the intermediate pressure port 11e and the first compression The refrigerant discharged from the mechanism 11b does not merge. The liquid refrigerant separated by the gas-liquid separator 16 flows out to the first three-way joint 17a (outdoor heat exchanger 20) side because the second electric expansion valve 15b is fully closed. There is no.

The refrigerant discharged from the first compression mechanism 11b (a1 ₉ points in FIG. 9) via the bypass port 11g, and flows into the bypass passage 19. Refrigerant flowing into the bypass passage 19 is reduced in pressure when passing through the bypass passage 19 and the check valve 19a (a1 ₉ points in FIG. 9 → a3 ₉ points), through the first three-way joint 17a, the outdoor heat exchanger 20 flows into. At this time, the refrigerant flowing into the first three-way joint 17a does not flow out to the gas-liquid separator 16 side because the second electric expansion valve 15b is fully closed.

Then, refrigerant flowing into the outdoor heat exchanger 20, radiates heat in the outdoor heat exchanger 20 to the outside air (a3 ₉ points → a0 ₉ points in FIG. 9). At this time, the frost attached to the outdoor heat exchanger 20 is melted and removed by the amount of heat released from the refrigerant. Since the third electric expansion valve 15c is fully closed and the second on-off valve 18b is open, the refrigerant flowing out of the outdoor heat exchanger 20 is compressed in the same manner as in the normal heating operation mode. 11 is sucked from the suction port 11d and compressed again.

  As described above, in the defrosting operation mode, the outdoor heat exchanger 20 can be defrosted by the amount of heat of the refrigerant discharged from the first compression mechanism 11b. Further, since the refrigerant discharged from the second compression mechanism 11c flows into the indoor condenser 13, even during the defrosting operation, the amount of heat absorbed by the refrigerant in the water-refrigerant heat exchanger 14, that is, the engine 41 Heating of the passenger compartment can be realized using waste heat.

  Next, the warming-up heating operation mode, that is, the heating operation mode in which the vehicle interior is heated using only outside air as a heat source will be described.

  In this warming-up heating operation mode, as shown in FIG. 6, the air conditioning control device 50 switches the three-way valve 12 to a refrigerant flow path that connects the discharge side of the first compression mechanism 11b and the suction side of the second compression mechanism 11c, The first electric expansion valve 15a is fully opened, the second electric expansion valve 15b is in a throttle state, the third electric expansion valve 15c is fully closed, the first on-off valve 18a is closed, and the second on-off valve 18b is opened. Further, the first cooling water pump 42a is stopped.

Thereby, the heat pump cycle 10 is switched to the refrigerant | coolant flow path through which a refrigerant | coolant flows as shown by the solid line arrow of FIG. Therefore, in the heat pump cycle 10 in the warming-up heating operation mode, as shown in the Mollier diagram of FIG. 10, the high-pressure refrigerant (point a _{10 in} FIG. 10) discharged from the discharge port 11 f of the compressor 11 is condensed in the room. by radiating flows into vessel 13 (a ₁₀ point in FIG. 10 → b ₁₀ points), the vehicle compartment blown air is heated.

  Further, the refrigerant flowing out of the indoor condenser 13 flows into the water-refrigerant heat exchanger 14 without being decompressed and expanded because the first electric expansion valve 15a is fully opened. In the water-refrigerant heat exchanger 14, since the first cooling water pump 42a is stopped, the refrigerant flows out of the water-refrigerant heat exchanger 14 without being heated. The refrigerant flowing out of the water-refrigerant heat exchanger 14 is gas-liquid separated by the gas-liquid separator 16.

Gas-liquid separator 16 liquid-phase refrigerant separated by ₍₁₀ f in FIG. 10) is flowed into the second electric expansion valve 15b, f ₁₀ (FIG. 10 to be decompressed and expanded until the low-pressure refrigerant Point → g ₁₀ points). The gas-phase refrigerant separated by the gas-liquid separator 16 does not flow out to the intermediate pressure port 11e side of the compressor 11 because the first on-off valve 18a is closed.

The low-pressure refrigerant decompressed and expanded by the second electric expansion valve 15b flows into the outdoor heat exchanger 20 via the first three-way joint 17a and evaporates by absorbing heat from the outside air, as in the normal heating operation mode. (G ₁₀ points → h ₁₀ points in FIG. 10). Further, the refrigerant that has flowed out of the outdoor heat exchanger 20 flows into the accumulator 22 through the second and third three-way joints 17b and 17c, and is separated into gas and liquid.

Then, (a0 ₁₀ points in FIG. 10) the gas-phase refrigerant separated by the accumulator 22 is again compressed from the suction port 11d of the compressor 11 is sucked into the first compression mechanism 11b. Since the first on-off valve 18a is closed, the refrigerant discharged from the first compression mechanism 11b (point a1 _{10 in} FIG. 10) does not merge with the refrigerant flowing in from the intermediate pressure port 11e, and thus the second compression mechanism 11b. And then compressed again.

  As described above, in the warming-up heating operation mode, the vehicle interior air can be heated by the amount of heat of the refrigerant discharged from the compressor 11 by the indoor condenser 13 to heat the vehicle interior.

  At this time, since the first cooling water pump 42a that is the flow rate adjusting means is stopped, it is possible to suppress the heat quantity of the cooling water from being absorbed by the refrigerant during the warm-up of the engine 41. As a result, it is possible to prevent the engine 41 from being prevented from being warmed up by heating the passenger compartment.

(B) Warm-up promotion operation mode The warm-up promotion operation mode is an operation mode that promotes warm-up of the engine 41 by heating the coolant of the engine 41 without heating the passenger compartment. The operation in the warm-up promotion operation mode is when the operation of the engine 41 is started and the operation switch of the vehicle air conditioner 1 on the operation panel is not turned on (OFF), and the temperature of the cooling water is the reference cooling water. It starts when the temperature is lower than the temperature, and is stopped when the temperature of the cooling water rises above the reference cooling water temperature.

  In the warm-up promotion operation mode, as shown in FIG. 6, the air-conditioning control device 50 is similar to the warm-up heating operation mode in the three-way valve 12, the first to third electric expansion valves 15 a to 15 b, the first and first The two on-off valves 18a and 18b are operated, and the first cooling water pump 42a is operated so as to pressure-feed a predetermined flow rate of cooling water. 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 arrows in FIG. 4, and the cooling water is supplied to the water-refrigerant heat exchanger 14.

  Further, in the warm-up promotion operation mode, the air conditioning controller 50 closes the vehicle interior air passage of the indoor condenser 13 by the air mix door 34 that is the heat exchange amount adjusting means, and the vehicle interior air blown from the blower 32 is blown. The opening degree of the air mix door 34 is controlled so that the total air volume of the air bypasses the indoor condenser 13.

Therefore, in the heat pump cycle 10 of promotion of warming operation mode, as shown in the Mollier diagram of FIG. 11, the high-pressure refrigerant discharged from the discharge port 11f of the compressor 11 (a ₁₁ point in FIG. 11) is, the indoor condenser Even if it flows in 13, it will flow into the 1st electric expansion valve 15a, without radiating heat to vehicle interior blowing air.

Further, the refrigerant flowing into the first electric expansion valve 15a flows into the water-refrigerant heat exchanger 14 without being expanded under reduced pressure because the first electric expansion valve 15a is fully open. Water - In the refrigerant heat exchanger 14, the first cooling water pump 42a is activated, discharged from the compressor 11 high-temperature high-pressure refrigerant releases heat to the cooling water (a ₁₁ point of FIG. 11 → d ₁₁ points) . Thereby, the cooling water is heated and the warm-up of the engine 41 is promoted.

The refrigerant flowing out of the water-refrigerant heat exchanger 14 is gas-liquid separated by the gas-liquid separator 16. Then, (f ₁₁ points in FIG. 11) the gas-liquid separated in the separator 16 the liquid refrigerant, as in the warm-up time of the heating operation mode, vacuum until pressure refrigerant in the second electric expansion valve 15b is expanded (f ₁₁ points in FIG. 11 → g ₁₁ points), absorbs heat from the outside air at the outdoor heat exchanger 20 to evaporate (g ₁₁ points in FIG. 11 → h ₁₁ points).

Furthermore, the refrigerant that has flowed out of the outdoor heat exchanger 20 flows into the accumulator 22 through the second and third three-way joints 17b and 17c, and is separated into gas and liquid. Then, (a0 ₁₁ points in FIG. 11) the gas-phase refrigerant separated by the accumulator 22 is again compressed from the suction port 11d of the compressor 11 is sucked into the first compression mechanism 11b.

  As described above, in the warm-up promotion operation mode, the water-refrigerant heat exchanger 14 cools the cooling water without releasing the heat quantity of the refrigerant discharged from the compressor 11 by the indoor condenser 13 to the air blown into the vehicle interior. The engine 41 can be warmed up by radiating heat.

(C) Cooling operation mode and dehumidifying operation mode Operation in the cooling operation mode is performed when the operation switch of the vehicle air conditioner 1 on the operation panel is turned on (ON) and the cooling operation mode is selected by the selection switch. Be started.

  In this cooling operation mode, as shown in FIG. 6, the air conditioning control device 50 switches the three-way valve 12 to the refrigerant flow path connecting the discharge side of the first compression mechanism 11 b and the suction side of the second compression mechanism 11 c, The second electric expansion valves 15a and 15b are fully opened, the third electric expansion valve 15b is in a throttle state, the first and second on-off valves 18a and 18b are closed, and the first cooling water pump 42a is stopped.

  Thereby, the heat pump cycle 10 is switched to the refrigerant | coolant flow path through which a refrigerant | coolant flows as shown by the solid line arrow of FIG. Further, in the cooling operation mode, as in the warm-up promotion operation mode, the air conditioning control device 50 controls the opening degree of the air mix door 34 so that the total air volume of the vehicle interior blown air bypasses the indoor condenser 13.

Therefore, in the heat pump cycle 10 in the cooling operation mode, as shown in the Mollier diagram of FIG. 12, the high-pressure refrigerant (point a _{12 in} FIG. 12) discharged from the discharge port 11 f of the compressor 11 is sent to the indoor condenser 13. Even if it flows in, it does not radiate heat to the air blown into the passenger compartment, is not decompressed and expanded by the first electric expansion valve 15a, and is further heated by the water-refrigerant heat exchanger 14 without being heated. It flows out of the exchanger 14.

  The refrigerant that has flowed out of the water-refrigerant heat exchanger 14 flows into the gas-liquid separator 16. In the cooling operation mode, the refrigerant does not radiate heat in the indoor condenser 13 and the water-refrigerant heat exchanger 14, and further, the refrigerant is not decompressed in the first electric expansion valve 15a. The refrigerant flowing into the liquid separator 16 becomes a gas phase refrigerant. Therefore, the gas-liquid separator 16 functions as a simple refrigerant passage without performing the function of separating the gas-liquid of the refrigerant.

  The refrigerant flowing into the gas-liquid separator 16 does not flow out to the intermediate pressure port 11e side of the compressor 11 because the first on-off valve 18a is closed, so that the second electric expansion valve 15b and the first three-way It flows into the outdoor heat exchanger 20 through the joint 17a. At this time, since the second electric expansion valve 15b is fully opened, the refrigerant flows into the outdoor heat exchanger 20 without being decompressed and expanded.

The refrigerant that has flowed into the outdoor heat exchanger 20 exchanges heat with the outside air to dissipate heat, thereby reducing its enthalpy (a ₁₂ points → h ₁₂ points in FIG. 12). And since the 2nd on-off valve 18b is closed, the refrigerant | coolant which flowed out from the outdoor heat exchanger 20 is decompressed and expanded until it flows into the 3rd electric expansion valve 15c via the 2nd three-way joint 17b, and turns into a low pressure refrigerant | coolant. (H ₁₂ points → i ₁₂ points in FIG. 12).

The refrigerant that has flowed out of the third electric expansion valve 15c flows into the indoor evaporator 21, absorbs heat from the air blown by the vehicle interior blown by the blower 32, and evaporates (i ₁₂ points → j ₁₂ points in FIG. 12). . Thereby, vehicle interior blowing air is cooled. The refrigerant that has flowed out of the indoor evaporator 21 flows into the accumulator 22 through the third three-way joint 17c and is separated into gas and liquid.

Then, (a0 ₁₂ points in FIG. 12) separated gas-phase refrigerant at the accumulator 22 is again compressed from the suction port 11d of the compressor 11 is sucked into the first compression mechanism 11b. Since the first on-off valve 18a is closed, the refrigerant discharged from the first compression mechanism 11b (point a1 _{12 in} FIG. 12) does not merge with the refrigerant flowing in from the intermediate pressure port 11e, and thus the second compression mechanism 11b. And then compressed again.

  As described above, in the cooling operation mode, the low-pressure refrigerant absorbs heat from the vehicle interior blown air and evaporates in the room evaporator 21, whereby the vehicle interior blown air is cooled and the vehicle interior can be cooled.

  Next, the dehumidifying operation mode will be described. In the dehumidifying operation mode, as shown in FIG. 6, the air conditioning control device 50 switches to the same refrigerant flow path as in the cooling operation mode, and stops the first cooling water pump 42a. Therefore, in the heat pump cycle 10 in the dehumidifying operation mode, the refrigerant flow path is switched to the refrigerant flow path as shown by the solid line arrow in FIG.

  Further, in the cooling operation mode, the air conditioning control device 50 controls the opening degree of the air mix door 34 as in the normal heating operation mode. That is, the opening degree of the air mix door 34 is adjusted so that the temperature of the air blown into the passenger compartment becomes a passenger's desired temperature set by the passenger compartment temperature setting switch.

Therefore, in the heat pump cycle 10 in the dehumidifying operation mode, as shown in the Mollier diagram of FIG. 13, the high-pressure refrigerant (point a _{13 in} FIG. 13) discharged from the discharge port 11 f of the compressor 11 enters the indoor condenser 13. It dissipates heat to the indoor air blown Te (a ₁₃ point of FIG. 13 → b ₁₃ points), and flows into the first electric expansion valve 15a. Further, the outdoor heat exchanger 20, the refrigerant in the indoor condenser 13 and radiates heat to the indoor air blown further radiator (b ₁₃ points in FIG. 13 → h ₁₃ points). Other operations are the same as those in the cooling operation mode.

  As described above, in the dehumidifying operation mode, the low-pressure refrigerant absorbs heat from the air blown into the vehicle interior and evaporates in the indoor evaporator 21, whereby the air blown into the vehicle interior is cooled and dehumidified. Furthermore, dehumidifying operation in which the dehumidified vehicle interior blown air is reheated by the amount of heat of the refrigerant discharged from the compressor 11 by the indoor condenser 13 to raise the passenger's desired temperature and blow it out into the vehicle interior. It can be carried out.

  In the vehicle air conditioner 1 of the present embodiment, various operation modes can be realized by switching the refrigerant flow path of the heat pump cycle 10 as described above. Further, in the defrosting operation mode, not only can the outdoor heat exchanger 20 be defrosted, but also heating of the vehicle interior can be realized using the waste heat of the engine 41.

  At this time, the refrigerant discharged from the second compression mechanism 11c directly flows into the indoor condenser 13, so that the pressure loss of the refrigerant is not unnecessarily increased as in the prior art. Furthermore, since it is not necessary to provide a dedicated heat exchanger for heating the air blown in the vehicle interior during the defrosting operation mode, the vehicle interior air can be efficiently heated in the defrosting operation mode with a simple configuration. it can.

(Second Embodiment)
In the present embodiment, as shown in the overall configuration diagram of FIG. 14, a fourth three-way joint 17d as a branching portion that branches the flow of the refrigerant flowing out from the indoor condenser 13 is added to the first embodiment, One of the branched refrigerants flows out to the first electric expansion valve 15a side, and the other branched refrigerant flows out to the second electric expansion valve 15b side, thereby simplifying the cycle configuration of the heat pump cycle 10 An example will be described.

  Specifically, in the present embodiment, the refrigerant outlet of the refrigerant side flow path 14a of the water-refrigerant heat exchanger 14 is directly connected to the intermediate pressure port 11e of the compressor 11 in the first embodiment. The other refrigerant outlet of the fourth three-way joint 17d is directly connected to the refrigerant inlet of the second electric expansion valve 15b. Therefore, in the heat pump cycle 10 of the present embodiment, the gas-liquid separator 16 and the first on-off valve 18a are eliminated. Other configurations are the same as those of the first embodiment.

  In the overall configuration diagram of the heat pump cycle 10 shown in FIG. 14, the refrigerant flow in the normal heating operation mode is indicated by solid arrows. Further, in FIG. 14, the same or equivalent parts as those in the first embodiment are denoted by the same reference numerals. The same applies to the following drawings.

  Next, the operation of the vehicle air conditioner 1 according to this embodiment will be described with reference to FIGS. FIG. 15 is a chart showing the operating state of the refrigerant flow switching means of the present embodiment, and FIG. 16 is a Mollier diagram showing the state of the refrigerant in the heat pump cycle 10 in the normal heating operation mode. Moreover, as shown in FIG. 15, in the heat pump cycle 10 of this embodiment, the refrigerant flow path in the warm-up promotion operation mode is not set.

  First, in the normal heating operation mode, the air conditioning control device 50, like the first embodiment, the three-way valve 12, the second, and the third electric type constituting the first electric expansion valve 15a and the refrigerant flow switching means. The operating states of the expansion valves 15b and 15c and the first and second on-off valves 18a and 18b are switched as shown in FIG. 15, and the first cooling water pump 42a is pumped with a predetermined predetermined flow rate of cooling water. Operate.

Therefore, in the heat pump cycle 10 in the normal heating operation mode, as shown in the Mollier diagram of FIG. 16, the high-pressure refrigerant (a in FIG. 16) discharged from the discharge port 11f of the compressor 11 as in the first embodiment. ₁₆ points) releases heat in the indoor condenser 13 (a ₁₆ point of FIG. 16 → b ₁₆ points), and flows into the fourth three-way joint 17d.

One refrigerant branched at the fourth three-way joint 17d is flows into the first electric expansion valve 15a, it is decompressed and expanded until the intermediate-pressure refrigerant (b ₁₆ → c ₁₆ points in FIG. 16), the water - The refrigerant is heated by the refrigerant heat exchanger 14 to increase its enthalpy (c ₁₆ point → d ₁₆ point in FIG. 16). The refrigerant heated by the water-refrigerant heat exchanger 14 flows into the intermediate pressure port 11e of the compressor 11.

  At this time, it is desirable that the throttle opening degree of the first electric expansion valve 15a is adjusted so that the refrigerant flowing into the intermediate pressure port 11e has a predetermined degree of superheat. Therefore, superheat degree detection means for detecting the superheat degree of the refrigerant flowing into the intermediate pressure port 11e may be added to the heat pump cycle 10.

The refrigerant flowing into the intermediate pressure port 11e of the compressor 11 merges with the refrigerant discharged from the first compression mechanism 11b (a1 ₁₆ point in FIG. 16) inside the compressor 11 (a2 ₁₆ point in FIG. 16), The air is sucked into the second compression mechanism 11c.

On the other hand, the other refrigerant branched at the fourth three-way joint 17d is flows into the second electric expansion valve 15b, is decompressed and expanded until the low-pressure refrigerant (b ₁₆ → g ₉ points in FIG. 16), the outdoor The heat exchanger 20 absorbs heat from the outside air and evaporates (g ₁₆ points → h ₁₆ points in FIG. 16).

The refrigerant that has flowed out of the outdoor heat exchanger 20 is sucked from the suction port 11d of the compressor 11 through the third three-way joint 17c and the accumulator 22, as in the first embodiment (point a0 _{16 in} FIG. 16). , Compressed again. Therefore, in the normal heating operation mode of the present embodiment, the vehicle interior blown air is heated by the amount of heat of the refrigerant discharged from the compressor 11 by the indoor condenser 13 as in the first embodiment, so that the interior of the vehicle interior is heated. Heating can be performed.

  At this time, the flow of the refrigerant flowing out of the indoor condenser 13 is branched by the fourth three-way joint 17d, and one of the branched refrigerants is heated by the water-refrigerant heat exchanger 14 and then the intermediate pressure port 11e. To the compressor 11 (specifically, the second compression mechanism 11c), and the other refrigerant absorbs heat from the outside air by evaporating in the outdoor heat exchanger 20.

  Therefore, in the normal heating operation mode of the present embodiment, as in the first embodiment, not only the amount of heat that the refrigerant has absorbed from the outside air in the outdoor heat exchanger 20, but also the amount of heat that the cooling water has, that is, the waste of the engine 41. The air blown into the passenger compartment can be efficiently heated using heat.

  Next, in the defrosting operation mode, as shown in FIG. 15, the air conditioning control device 50 switches the operating states of the various control devices 12, 15 a to 15 c, 18 b to the same state as in the first embodiment, and further 1 The cooling water pump 42a is operated so as to pump a predetermined flow rate of cooling water. Thereby, the cycle similar to 1st Embodiment can be comprised and it can be act | operated similarly.

  Next, in the warming-up heating operation mode, as shown in FIG. 15, the air conditioning control device 50 fully closes the first electric expansion valve 15 a and sets the operating states of other various control devices to the first embodiment. And the first cooling water pump 42a is stopped. Thereby, the cycle similar to 1st Embodiment can be comprised and it can be act | operated similarly.

  Next, in the cooling operation mode and the dehumidifying operation mode, as shown in FIG. 15, the air conditioning control device 50 sets the first electric expansion valve 15 a to the fully closed state and performs the operating states of other various control devices in the first implementation. While switching to the same state as the embodiment, the first cooling water pump 42a is stopped. Thereby, the cycle similar to 1st Embodiment can be comprised and it can be act | operated similarly.

  As described above, also in the vehicle air conditioner 1 of the present embodiment, various operation modes can be realized by switching the refrigerant flow path of the heat pump cycle 10 as in the first embodiment. Furthermore, according to the heat pump cycle 10 of the present embodiment, the vehicle interior blown air can be efficiently heated even in the defrosting operation mode with a simpler configuration.

(Other embodiments)
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.

  (1) In the above-described embodiment, an example in which the heat pump cycle 10 that can be switched to various operation modes is applied to a vehicle air conditioner has been described. However, the heat pump cycle 10 of the present invention has at least a normal heating operation mode and defrosting. If the operation mode can be switched, it is possible to obtain an effect that the heat exchange target fluid can be efficiently heated in the defrost operation mode with a simple configuration.

  (2) In the above-described embodiment, the example in which the heat pump cycle 10 of the present invention is applied to the vehicle air conditioner of the hybrid vehicle has been described, but it is needless to say that the heat pump cycle 10 may be applied to other vehicle air conditioners. For example, it is effective when applied to a diesel vehicle with little waste heat from the engine. Furthermore, the application of the present invention is not limited to a vehicle, and may be applied to, for example, a stationary air conditioner, a cold storage, a vending machine cooling heating device, and the like.

  (3) In the above-described embodiment, the example in which the cooling water of the engine 41 is employed as the external heat source has been described. However, the external heat source is not limited to this. For example, when the heat pump cycle 10 is applied to a vehicle air conditioner, exhaust gas discharged from the engine 41 may be adopted as an external heat source, or an electric device such as an inverter or an electric motor mounted on the vehicle is cooled. Cooling water to be used may be adopted. Therefore, the present invention can also be applied as a refrigeration cycle apparatus for an electric vehicle.

  (4) In the above-described embodiment, an example in which a two-stage booster type electric compressor that drives the first and second compression mechanisms 11b and 11c with a common electric motor as the compressor 11 has been described. The format of the compressor is not limited to this. Of course, you may employ | adopt the two-stage pressure | voltage rise type electric compressor which drives the two fixed capacity type 1st, 2nd compression mechanisms 11b and 11c with a different electric motor.

  Further, the first and second compression mechanisms 11b and 11c do not need to be accommodated in the same housing 11a, and two different compressors may be arranged in series. Of course, the three-way valve 12 may also be disposed outside the compressor housing.

  (5) In the above-described embodiment, the example in which the refrigerant flow switching means is configured by the three-way valve 12, the second and third electric expansion valves 15b and 15c, and the first and second on-off valves 18a and 18b has been described. However, the refrigerant flow path switching means is not limited to this.

  For example, in the first embodiment, the third three-way joint 17c is abolished, and in a normal heating operation mode, the refrigerant flow path connecting the outlet side of the outdoor heat exchanger 20 and the inlet side of the accumulator 22 is switched, In the cooling operation mode, an electric three-way valve that switches to a refrigerant flow path that connects the outlet side of the outdoor heat exchanger 20 and the third electric expansion valve 15c may be employed.

  In the above-described embodiment, the second and third electric expansion valves 15b and 15c having the fully-closed function are employed, so that the second and third electric expansion valves 15b and 15c serve as the refrigerant flow switching means. However, of course, as the second and third electric expansion valves 15b and 15c, electric expansion valves that do not have a fully-closed function are adopted, and the first and second electric expansion valves are used. An on-off valve may be arranged upstream or downstream of 15a and 15b. In this case, the on-off valve constitutes the refrigerant flow path switching means.

  (6) In the above-described embodiment, an example is described in which the third electric expansion valve 15c is used as the decompression means for the cooling operation mode in which the high-pressure refrigerant is decompressed and expanded until it becomes the low-pressure refrigerant in the cooling operation mode and the dehumidifying operation mode. However, the decompression means for the cooling operation mode is not limited to this. For example, a temperature type expansion valve may be employed.

  The temperature type expansion valve has a temperature sensing part arranged in the refrigerant passage on the outlet side of the indoor evaporator 21 and is based on the temperature and pressure of the refrigerant on the outlet side of the indoor evaporator 21 in the cooling operation mode. It is possible to employ a mechanism that detects the degree of superheat of the outlet side refrigerant and adjusts the valve opening degree (refrigerant flow rate) by a mechanical mechanism so that the degree of superheat of the refrigerant on the outlet side of the indoor evaporator 21 becomes a predetermined value.

  In addition, an ejector that functions as a refrigerant depressurizing unit that depressurizes the refrigerant and functions as a refrigerant circulating unit that circulates the refrigerant by suction of the refrigerant flow ejected at high speed as the depressurizing unit for the cooling operation mode. It may be adopted.

  Specifically, the ejector includes a nozzle part that decompresses the refrigerant, a refrigerant suction port that sucks the refrigerant by a flow of the high-speed jet refrigerant that is jetted from the nozzle part, and a refrigerant that is a mixed refrigerant of the jet refrigerant and the suction refrigerant It has a body part formed with a diffuser part for gradually expanding the passage area and converting the kinetic energy of the mixed refrigerant into pressure energy.

  As this nozzle part, a fixed nozzle part with a fixed throttle passage area may be adopted, or a variable nozzle part configured to be able to change the refrigerant passage area may be adopted. The variable nozzle portion includes a needle valve that is disposed inside the nozzle portion and adjusts the refrigerant passage area of the nozzle portion, and an electric actuator that includes a stepping motor that displaces the needle valve in the axial direction of the nozzle portion. Is.

  And as an example in the case of applying the ejector 151 as the pressure reducing means for the cooling operation mode of the heat pump cycle 10 of the first embodiment, as shown in the overall configuration diagram of FIG. 17, the refrigerant of the third three-way joint 17c and the ejector 151 A branching portion 152 that branches the refrigerant flow is disposed between the inlet and the inlet, and one of the branched refrigerants flows into the ejector 151. Furthermore, the indoor evaporator 21 is connected to the refrigerant outlet of the ejector 151.

  On the other hand, the other branched refrigerant is caused to flow into the second indoor evaporator 21a via the decompression means 153 such as a fixed throttle, and the refrigerant outlet of the second indoor evaporator 21a is connected to the refrigerant suction port of the ejector 151. That's fine. Further, in the indoor air conditioning unit 30, the indoor evaporator 21 may be disposed on the upstream side of the air flow of the second indoor evaporator 21a. FIG. 17 shows the refrigerant flow in the cooling operation mode.

  Thereby, the refrigerant | coolant evaporation temperature of the indoor evaporator 21 can be raised from the refrigerant | coolant evaporation temperature of the 2nd indoor evaporator 21a by the pressure | voltage rise effect | action in the diffuser part of the ejector 151 at the time of air_conditionaing | cooling operation mode. Therefore, the temperature difference between the refrigerant evaporation temperature of the indoor evaporator 21 and the second indoor evaporator 21a and the air blown into the vehicle interior can be ensured, and the air blown into the vehicle interior can be efficiently cooled.

  Furthermore, since the suction pressure of the compressor 11 can be increased by the boosting action in the diffuser section and the driving power of the compressor 11 can be reduced, the COP in the cooling operation mode and the dehumidifying operation mode can be improved. Of course, you may employ | adopt an ejector as a pressure reduction means for cooling of the heat pump cycle 10 of 2nd Embodiment.

  (7) In the above-described embodiment, the example in which the first cooling water pump 42a is employed as the flow rate adjusting means for adjusting the flow rate of the cooling water flowing into the water-refrigerant heat exchanger 14 has been described. It is not limited to. For example, a flow rate adjusting valve that adjusts the flow rate of the cooling water flowing into the cooling water side passage 14b of the water-refrigerant heat exchanger 14 may be employed.

  (8) In the above-described embodiment, an example is described in which the air mix door 34 is employed as a heat exchange amount adjusting means for adjusting the heat exchange amount between the refrigerant discharged from the second compression mechanism 11c in the indoor condenser 13 and the air blown into the vehicle interior. However, the heat exchange amount adjusting means is not limited to this. For example, a sliding door that changes the air passage area of the heat exchange core surface of the indoor condenser 13 may be employed.

  (9) In the above-described embodiment, an example in which a normal chlorofluorocarbon refrigerant is employed as the refrigerant has been described, but the type of refrigerant is not limited to this. Natural refrigerants such as carbon dioxide, hydrocarbon refrigerants, and the like may be employed. Furthermore, the heat pump cycle 10 may constitute a supercritical refrigeration cycle in which the refrigerant discharged from the compressor 11 is equal to or higher than the critical pressure of the refrigerant.

11b 1st compression mechanism 11c 2nd compression mechanism 12 Three-way valve 13 Indoor condenser 17a-17d First to fourth three-way joint 14 Water-refrigerant heat exchanger 15a-15c First to third electric expansion valves 16 Gas-liquid separation 18a, 18b First and second on-off valves 20 Outdoor heat exchanger 21 Indoor evaporator 34 Air mix door 41 Engine 42a First cooling water pump 42a

Claims (5)

First and second compression mechanisms (11b, 11c) for compressing and discharging the refrigerant;
A use side heat exchanger (13) for exchanging heat between the refrigerant discharged from the second compression mechanism (11c) and the heat exchange target fluid;
First decompression means (15a) for decompressing the refrigerant that has flowed out of the use side heat exchanger (13);
Heating means (14) for heating the refrigerant decompressed by the first decompression means (15a) by the amount of heat of the external heat source;
A gas-liquid separator (16) that separates the gas-liquid refrigerant flowing out from the heating means (14) and causes the separated gas-phase refrigerant to flow out to the suction side of the second compression mechanism (11c);
Second decompression means (15b) for decompressing the liquid-phase refrigerant separated by the gas-liquid separator (16);
An outdoor heat exchanger (20) for exchanging heat between the refrigerant and the outside air to flow out to the suction side of the first compression mechanism (11b);
Refrigerant flow path switching means (12) for switching a refrigerant flow path in a heating operation mode for heating the heat exchange target fluid and a refrigerant flow path in a defrost operation mode for melting frost attached to the outdoor heat exchanger (20). ... with 18a)
The refrigerant flow switching means (12... 18a)
During the heating operation mode, the refrigerant discharged from the first compression mechanism (11b) is sucked into the second compression mechanism (11c), and the refrigerant depressurized by the second decompression means (15b) is Switch to the refrigerant flow path to flow into the heat exchanger (20),
The heat pump cycle characterized by switching to the refrigerant flow path into which the refrigerant discharged from the 1st compression mechanism (11b) flows into the outdoor heat exchanger (20) at the time of the defrosting operation mode. The refrigerant channel switching means includes a refrigerant channel that connects the discharge side of the first compression mechanism (11b) and the suction side of the second compression mechanism (11c), the discharge side of the first compression mechanism (11b), and the outdoor side. The heat pump cycle according to claim 1 , wherein the heat pump cycle includes a three-way valve (12) for switching a refrigerant flow path connecting the inlet side of the heat exchanger (20). A heat pump cycle applied to a vehicle air conditioner,
The heat exchange target fluid is vehicle interior air blown into the vehicle interior,
3. The heat pump cycle according to claim 1, wherein the external heat source is cooling water that cools the internal combustion engine (41) that outputs a driving force for traveling the vehicle. 4. The heat pump cycle according to claim 3 , further comprising a flow rate adjusting means (42a) for adjusting a flow rate of the cooling water flowing into the heating means (14). The heat exchanger (13) further includes a heat exchange amount adjusting means (34) for adjusting a heat exchange amount between the refrigerant discharged from the second compression mechanism (11c) and the heat exchange target fluid in the use side heat exchanger (13). The heat pump cycle according to any one of claims 1 to 4 .

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