JP2021084545A - Air conditioner for vehicle and driving mode switching method - Google Patents

Abstract

To provide an air conditioner for vehicle which shortens the switching time while preventing the generation of noise at the switching of driving modes of a refrigeration cycle.SOLUTION: In an air conditioner for vehicle, a compressor 11, a first heat exchanger 2, a first expansion device 12, a cabin-outside heat exchanger 4, a second expansion device 14 and a second heat exchanger 3 are connected in the loop shape at least in this order. The air conditioner for vehicle includes a refrigeration cycle in which the first heat exchanger 2 and the first expansion device 12 are connected and the cabin-outside heat exchanger 4 and the second expansion device 14 are connected via a first bypass flow path 16 that includes a first refrigerant control unit 15, a reverse-flow blocking part 13 is provided on the downstream side of the cabin-outside heat exchanger 4 and on the upstream side with respect to a confluent portion with the first bypass flow path 16, the cabin-outside heat exchanger 4 and the reverse-flow blocking part 13 are connected and the second heat exchanger 3 and the compressor 11 are connected via a second bypass flow path 18 that includes a second refrigerant control unit 17. The second refrigerant control unit 17 is constituted by a throttle valve that can narrow down and open/close the second bypass flow path 18.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle air conditioner provided with a refrigeration cycle capable of switching an operation mode quickly and without noise, and an operation mode switching method.

Conventionally, there is known an air conditioner for vehicles that not only cools and heats the vehicle interior by using a heat pump type refrigeration cycle but also enables dehumidifying operation. For example, Patent Document 1 (Japanese Patent Laid-Open No. 2012-250708) describes it. Discloses a refrigeration cycle that switches an operation mode to a cooling operation mode, a heating operation mode, or a dehumidifying operation mode by changing the operating state of a plurality of electromagnetic valves and switching the refrigerant circuit.
Further, in this document, in order to suppress deterioration of durability of a solenoid valve or the like as a cycle component device, when switching the operation mode, the compressor is stopped and the high pressure side refrigerant pressure on the discharge side of the compressor is described. It has been proposed to switch the refrigerant circuit when the value falls below the reference value.

Japanese Unexamined Patent Publication No. 2012-250708

By the way, when switching between various operation modes in the refrigeration cycle, opening and closing of various valves is controlled in order to change the refrigerant flow path, but if the pressure difference between the refrigerants is large between the upstream side and the downstream side of the valves. When the valve is opened, the high-pressure refrigerant flows into the low-pressure path at once, causing a sudden sound.

In order to avoid such inconvenience, as shown in the prior art, the compressor is temporarily stopped, the refrigerant circuit is switched after the high pressure side refrigerant pressure on the discharge side of the compressor becomes equal to or lower than the reference value, and then the refrigerant circuit is switched. It is also conceivable to adopt a method of operating the compressor again.

However, if such a switching method is adopted, it is necessary to stop the compressor every time the operation mode of the refrigeration cycle is switched, and the switching cannot be performed until the pressure on the discharge side of the compressor drops below the reference value. .. Further, since the compressor is started from the stopped state, it takes a considerable amount of time to perform steady operation in the switched operation mode.

The present invention has been made in view of the above circumstances, and uses a vehicle air conditioner capable of shortening the switching time while preventing the generation of noise when switching the operation mode of the refrigeration cycle. The main issue is to provide a method for switching the operation mode.

In order to achieve the above problems, the vehicle air conditioner according to the present invention includes a compressor, a first heat exchanger arranged in the air conditioner unit and whose ventilation amount is adjusted by a damper, and the air conditioner unit. A second exchanger arranged upstream of the first heat exchanger in the air conditioning unit, a vehicle interior heat exchanger capable of exchanging heat with the outside air, and a refrigerant flow path are narrowed down. It has a first expansion device that can be opened and closed, and a second expansion device that can narrow and close the refrigerant flow path.
The compressor, the first heat exchanger, the first inflator, the passenger compartment heat exchanger, the second inflator, and the second heat exchanger are connected in a loop at least in this order. And
The refrigerant flow path between the first heat exchanger and the first expansion device and the refrigerant flow path between the passenger compartment outdoor heat exchanger and the second expansion device are the first refrigerant. Connected via a first bypass flow path that can be opened and closed by the control unit
Of the refrigerant flow paths between the vehicle interior heat exchanger and the second expansion device, the flow of the refrigerant from the merging portion to the upstream side is upstream from the merging portion with the first bypass flow path. A backflow blocking portion for blocking is provided, and a refrigerant flow path between the passenger compartment outdoor heat exchange and the backflow blocking portion and a refrigerant flow path between the second heat exchanger and the compressor are provided. A vehicle air conditioner having a refrigeration cycle connected via a second bypass flow path provided with two refrigerant control units.
The second refrigerant control unit is characterized by being configured by a throttle valve capable of throttle and open / close the second bypass flow path.

Therefore, since such a refrigeration cycle is used, the vehicle interior heat exchanger is changed from the operation mode in which noise generation is confirmed, that is, the operation mode in which the vehicle interior heat exchanger functions as a radiator. When switching to an operation mode in which the above is functioned as a heat absorber or an operation mode in which the heat exchange function by the outside heat exchanger is not used, more specifically, the refrigerant is applied to the first bypass flow path and the second bypass flow path. When switching from the operation mode in which the refrigerant does not pass through to the operation mode in which the refrigerant flows through either or both of the first pipe pass passage and the second bypass flow path, the second refrigerant control unit is temporarily closed from the closed state. By transitioning to the throttled state, it is possible to prevent the high-pressure refrigerant from flowing into the low-pressure path at once via the second bypass flow path, and to avoid the occurrence of sudden sound.

As a result, the operation mode in which the vehicle interior heat exchanger functions as a radiator is switched to the operation mode in which the vehicle interior heat exchanger functions as a heat absorber or the operation mode in which the heat exchange function by the vehicle interior heat exchanger is not used. In this case, it is not necessary to bother to stop the compressor in order to reduce the pressure difference between the front and rear of the refrigerant control unit.

Looking at a specific control operation example in which the operation mode is switched by the control means for switching and controlling the operation mode using the refrigeration cycle described above, for example, the dehumidifying heating (parallel) is performed from the cooling operation mode or the dehumidifying cooling operation mode depending on the control means. When switching to the operation mode, that is, after passing the refrigerant discharged from the compressor by the control means through the first heat exchange without dissipating heat or heat exchange, the first expansion device requires it. A first operation mode (cooling operation mode or) in which the pressure is reduced and the heat is dissipated by the heat exchanger outside the passenger compartment, and the dissipated refrigerant is further depressurized by the second expansion device and then absorbed by the second heat exchanger. From the dehumidifying / cooling operation mode), the refrigerant discharged from the compressor is radiated by the first heat exchanger, then passed through the first bypass flow path, depressurized by the second expansion device, and then the second. The heat is absorbed by the second heat exchanger, the pressure is reduced by the first expansion device, and then the heat is absorbed by the vehicle interior heat exchanger, and then the second bypass flow path is passed through and returned to the compressor. When switching to the operation mode (dehumidification / heating (parallel) operation mode),
From the state of the first operation mode, the second refrigerant control unit is set to the throttled state, and a part of the refrigerant that has passed through the vehicle interior heat exchanger is guided to the compressor via the second bypass flow path. 1 stage and
A second stage in which the first expansion device is fully opened, and
A third stage in which the first refrigerant control unit is opened and the refrigerant that has passed through the first heat exchanger is also passed through the first bypass flow path.
A fourth stage in which the first expansion device is squeezed to cause the outdoor heat exchanger to function as an endothermic device.
A fifth stage in which the second refrigerant control unit is fully opened, and
It is advisable to switch through sequentially.

If the first operation mode is switched to the second operation mode in the order described above, the pressure difference between the upstream side and the downstream side of the first refrigerant control unit is gradually reduced by the second stage. Even if the first bypass flow path is opened (third stage) by operating the refrigerant control unit, it is possible to avoid the inconvenience that the high-pressure refrigerant suddenly flows into the low-pressure side.
Further, since the pressure difference between the upstream side and the downstream side of the second refrigerant control unit is reduced by the fourth stage following the first to third stages, the second bypass flow path may be opened (fifth stage). , It is possible to avoid the inconvenience that the high-pressure refrigerant suddenly flows into the low-pressure side.
Therefore, when switching from the first operation mode to the second operation mode, it is possible to suppress the generation of noise, and it is possible to switch without stopping the compressor.

Further, as another control operation example, for example, when switching from the cooling operation mode or the dehumidifying / cooling operation mode to the dehumidifying / heating (bypass) operation mode by the control means, that is, the refrigerant discharged from the compressor by the control means is used. After the first heat exchanger dissipates heat or allows the refrigerant to pass through without heat exchange, the first expansion device decompresses the pressure as necessary and the external heat exchanger dissipates heat, and the radiated refrigerant is dissipated. From the first operation mode (cooling operation mode or dehumidifying cooling operation mode) in which the heat is absorbed by the second heat exchanger after being further depressurized by the second expansion device, the refrigerant discharged from the compressor is subjected to the first heat. A third operation mode (dehumidifying and heating (bypass)) in which heat is dissipated by the exchanger, only the first bypass flow path is passed, the pressure is reduced by the second expansion device, and then the heat is absorbed by the second heat exchanger. ) When switching to operation mode)
From the state of the first operation mode, the second refrigerant control unit is set to the throttled state, and a part of the refrigerant that has passed through the vehicle interior heat exchanger is guided to the compressor via the second bypass flow path. 1 stage and
A second stage in which the first expansion device is fully opened, and
A third stage in which the first refrigerant control unit is opened and the refrigerant that has passed through the first heat exchanger is also passed through the first bypass flow path.
A sixth stage in which the first expansion device is closed to block the flow to the passenger compartment heat exchanger, and the sixth stage.
It is advisable to switch through sequentially.

If the first operation mode is switched to the third operation mode in the order described above, the pressure difference between the upstream side and the downstream side of the first refrigerant control unit is gradually reduced by the second stage. Even if the first bypass flow path is opened (third stage) by operating the refrigerant control unit, it is possible to avoid the inconvenience that the high-pressure refrigerant suddenly flows into the low-pressure side.
Further, the sixth stage following the first to third stages makes it possible to realize a third operation mode in which the refrigerant does not flow through the second bypass flow path (the refrigerant flows only through the first bypass flow path). ..
Therefore, when switching from the first operation mode to the third operation mode, it is possible to suppress the generation of noise, and it is possible to switch without stopping the compressor.

As yet another control operation example, for example, when switching from the cooling operation mode or the dehumidifying / cooling operation mode to the heating operation mode by the control means, that is, the refrigerant discharged from the compressor by the control means is exchanged with the first heat. After passing through without radiating heat or exchanging heat with the device, the pressure is reduced as needed by the first expansion device and heat is dissipated by the heat exchanger outside the passenger compartment, and the radiated refrigerant is expanded by the second expansion. The refrigerant discharged from the compressor is dissipated by the first heat exchanger from the first operation mode (cooling operation mode or dehumidifying cooling operation mode) in which the heat is absorbed by the second heat exchanger after the pressure is further reduced by the apparatus. After that, the pressure is reduced by the first expansion device, heat is absorbed by the vehicle interior heat exchanger, and the refrigerant that has passed through the vehicle interior heat exchanger is returned to the compressor via the second bypass flow path. When switching to the operation mode (heating operation mode),
From the state of the first operation mode, the seventh stage in which the first expansion device is squeezed to make the vehicle interior heat effector function as a heat absorber, and
An eighth stage in which the second refrigerant control unit is in a throttled state and a part of the refrigerant that has passed through the vehicle interior heat exchanger is guided to the compressor via the second bypass flow path.
A ninth stage in which the second expansion device is closed to block the flow to the second heat exchanger and the second refrigerant control unit is fully opened.
It is advisable to switch through sequentially.

By switching from the first operation mode to the fourth operation mode in the order described above, first, in the seventh stage, when the first expansion device is throttled, the vehicle interior heat exchanger functions as a heat absorber and the first The pressure on the downstream side of the expansion device of 1 gradually decreases. However, immediately after the outside heat exchanger is made to function as an endothermic in the 7th stage, the pressure on the downstream side of the outside heat exchange is not necessarily sufficiently reduced, so that the 2nd stage is the 8th stage. By setting the refrigerant control unit of No. 1 in the throttled state, the pressure of the refrigerant guided to the compressor via the second bypass flow path 18 is reduced. As a result, it is possible to avoid the inconvenience that the medium- and high-pressure refrigerant suddenly flows into the suction side (accumulator) of the compressor, and it is possible to prevent the generation of noise.
After that, in the ninth stage, if the second expansion device is closed to block the flow to the second heat exchanger and the second refrigerant control unit is fully opened, no noise is generated and the second expansion device is fully opened. , It is possible to switch to the fourth operation mode without stopping the compressor.

Here, in the ninth stage, "the second expansion device is closed to block the flow to the second heat exchanger and the second refrigerant control unit is fully opened" means the second expansion device. This includes not only the case where the closing operation and the fully opening operation of the second refrigerant control unit are performed at the same time, but also the case where the closing operation of the second expansion device and the fully opening operation of the second refrigerant control unit are performed with a slight time difference. ..
When a time difference is provided, in order to switch the operation mode to the fourth operation mode while preventing the increase in the refrigerant pressure, the operation of fully opening the second refrigerant control unit is preceded by the operation of closing the second expansion device. It is preferable to carry out.

As described above, according to the present invention, the compressor, the first heat exchanger in the air conditioning unit, the first inflator, the vehicle interior heat exchanger capable of exchanging heat with the outside air, and the second inflator. , And the second heat exchanger arranged in the air conditioning unit and located upstream of the first heat exchanger are connected in a loop at least in this order, and the first heat exchanger and the first heat exchanger are connected. The refrigerant flow path between the expansion device and the refrigerant flow path between the vehicle interior heat exchanger and the second expansion device are opened and closed by the first refrigerant control unit via the first bypass flow path. A backflow blocking section is provided on the downstream side of the vehicle interior heat exchanger and upstream of the confluence with the first bypass flow path, and the refrigerant flow path between the vehicle interior heat exchanger and the backflow blocking section is provided. In a vehicle air conditioner having a refrigeration cycle in which the refrigerant flow path between the second heat exchanger and the compressor is connected via a second bypass flow path provided with a second refrigerant control unit. Since the second refrigerant control unit is composed of a throttle valve that can throttle and open / close the second bypass flow path, the pressure difference between the front and rear of the first refrigerant control unit and the front and rear of the second refrigerant control unit. When switching from an operation mode in which the refrigerant does not flow through the first bypass flow path and the second bypass flow path to an operation mode in which the refrigerant flows through at least one of these bypass flow paths, because the pressure difference can be reduced. In addition, it is possible to avoid the inconvenience that the high-pressure side refrigerant flows at once through the refrigerant control unit.
Therefore, when the operation mode of the refrigeration cycle is switched, it is possible to prevent the generation of noise, and the switching can be performed without stopping the compressor, so that the switching time can be shortened.

FIG. 1 shows an example of a vehicle air conditioner according to the present invention, FIG. 1 (a) is an overall configuration diagram thereof, and FIG. 1 (b) shows a state of an expansion device, a refrigerant control unit, an on-off valve, and a damper. Is a table showing each operation mode. FIG. 2 is a diagram showing each operation mode of the refrigeration cycle that can be switched according to the difference between the heat load and the target blowing temperature. The flow path through which the refrigerant is flowing is shown by a thick line, and the high-pressure flow path is shown by a thick solid line. The low pressure flow path is indicated by a thick dashed line. FIG. 3 is a diagram showing a dehumidifying / cooling (Series) operation mode and a dehumidifying / heating (Parallel) operation mode switched from this operation mode. FIG. 4 is a diagram illustrating each stage when switching from the dehumidifying / cooling (Series) operation mode to the dehumidifying / heating (Parallel) operation mode. FIG. 5 is a diagram showing a dehumidifying / cooling (Series) operation mode and a dehumidifying / heating (By-Pass) operation mode switched from this operation mode. FIG. 6 is a diagram illustrating each stage when switching from the dehumidifying / cooling (Series) operation mode to the dehumidifying / heating (By-Pass) operation mode. FIG. 7 is a diagram showing a dehumidifying / cooling (Series) operation mode and a heating operation mode switched from this operation mode. FIG. 8 is a diagram illustrating each stage when switching from the dehumidifying / cooling (Series) operation mode to the heating operation mode.

Hereinafter, embodiments of the vehicle air conditioner according to the present invention will be described with reference to the drawings.
FIG. 1 shows a vehicle air conditioner according to the present invention. The vehicle air conditioner is mounted on, for example, an automobile, and the first and second heat exchangers 2 and 2 are arranged in the air conditioner unit 1. 3 and an outdoor heat exchanger 4 arranged outside the air conditioning unit 1 and capable of exchanging heat with the outside air.

An inside / outside air switching device 6 is provided on the most upstream side of the air conditioning unit 1, and the inside air inlet 6a and the outside air inlet 6b are selectively opened by the intake door 7. The inside air or outside air selectively introduced into the air conditioning unit 1 is sucked by the rotation of the blower 8 and sent to the first and second heat exchangers 2 and 3, where the heat is exchanged to obtain a desired outlet. It is supplied to the passenger compartment from 9a to 9c.

The first heat exchanger 2 is arranged on the downstream side in the air flow direction in the air conditioning unit 1 with respect to the second heat exchanger 3, and is located on the upstream side in the air flow direction of the first heat exchanger 2. , The damper 10 is provided. The damper 10 can be changed from the position where the air volume passing through the first heat exchanger 2 is maximum (heating position: opening 100%) to the position where it is minimum (cooling position: opening 0%). By adjusting the opening degree, the ratio of the air passing through the first heat exchanger 2 and the air bypassing the first heat exchanger 2 can be adjusted.
The damper 10 is also called an air mix door. Further, in this example, the electric heat generating type heating device (PTC) 5 is arranged on the downstream side of the first heat exchanger 2 in the air conditioning unit 1.

The refrigerant inflow side 2a of the first heat exchanger 2 is connected to the discharge side α of the compressor 11, and the refrigerant outflow side 2b of the first heat exchanger 2 is the first expansion device (E-1) 12 It is connected to the inflow side 12a of. Further, the refrigerant outflow side 3b of the second heat exchanger 3 is connected to the suction side β of the compressor 11 via the accumulator 23. The first heat exchanger 2 is also called an indoor radiator or an inner capacitor.

The outflow side 12b of the first expansion device 12 is connected to the refrigerant inflow side 4a of the vehicle interior heat exchanger 4, and the refrigerant outflow side 4b of the vehicle interior heat exchanger 4 is the check valve 13 and the second check valve 13. It is connected to the refrigerant inflow side 3a of the second heat exchanger 3 via the expansion device (E-2) 14. Therefore, the compressor 11, the first heat exchanger 2, the first inflator 12, the passenger compartment outdoor heat exchanger 4, the check valve 13, the second inflator 14, the second heat exchanger 3, and the accumulator 23. , The refrigeration cycle connected in a loop in the order of the compressor 11 is formed.

Further, the refrigerant flow path between the refrigerant outflow side 2b of the first heat exchanger 2 and the inflow side 12a of the first expansion device 12, and the outflow side 13b of the check valve 13 and the second expansion device 14 The refrigerant flow path to and from the inflow side 14a is connected by a first bypass flow path 16 having a first refrigerant control unit (V-1) 15.

Further, the refrigerant flow path between the refrigerant outflow side 4b of the vehicle interior heat exchanger 4 and the inflow side 13a of the check valve 13, the refrigerant outflow side 3b of the second heat exchanger 3 and the inflow side 23a of the accumulator 23 The refrigerant flow path between the two is connected by a second bypass flow path 18 having a second refrigerant control unit (V-2) 17.

Here, in the above-described configuration example, the first expansion device 12 uses an electromagnetic expansion valve capable of narrowing, closing, and fully opening the refrigerant flow path by a control signal from the outside. Further, the second expansion device 14 uses an electromagnetic control valve capable of narrowing and closing the refrigerant flow path by a control signal from the outside.
The check valve 13 may be replaced with an on-off valve (V-3) 19 that opens and closes the flow path. The check valve 13 or the on-off valve (V-3) 19 constitutes a check valve.

Further, the first refrigerant control unit (V-1) 15 is composed of an on-off valve for opening and closing the first bypass flow path 16, and the second refrigerant control unit (V-2) 17 is a second. It is composed of a throttle valve that can throttle and open / close the bypass flow path 18 of the above. As the throttle valve, a needle type that changes the opening with a needle, a rotary type with a notch that changes the opening by rotating a rotary valve with a notch, and a spool with a notch formed on the outer peripheral surface are opened by changing the axial position. A segment type or the like that adjusts the degree can be adopted, and the structure and type thereof are not particularly limited.

Operation of the first and second expansion devices 12 and 14, opening and closing of the on-off valve 19 and the first refrigerant control unit 15, operation of the second refrigerant control unit 17, opening degree of the damper 10, discharge of the compressor 11 The amount is controlled by a control signal from the control unit 50. As the compressor 11, for example, an electric compressor is used.

The control unit 50 is known in itself and includes an input circuit including an A / D converter, a multiplexer, etc., an arithmetic processing circuit including a ROM, RAM, a CPU, etc., an output circuit including a drive circuit, etc., and is outside the vehicle interior. An outside temperature signal from the outside air temperature sensor 51 that detects the air temperature (outside temperature), an inside temperature signal from the inside air temperature sensor 52 that detects the vehicle interior temperature, and a solar radiation amount signal from the solar radiation sensor 53 that detects the amount of solar radiation. Various signals from the operation unit that sets the operation mode and the like are input, and these signals are processed according to a predetermined program.

In particular, when switching the operation mode of the refrigeration cycle 100 (expansion devices 12, 14, on-off valves 19, refrigerant control units 15, 17, and changing the operating state of the damper), the state of the heat load received by the refrigeration cycle (vehicle). The difference (Tm-Tset) between the total signal (Tm) that takes into account the outdoor air temperature, vehicle interior air temperature, solar radiation, etc., and the target blowout temperature (Tset) that takes into account the desired indoor temperature set by the occupants. ) Can be switched according to the size.
If this difference is larger than the first predetermined value, the mode is switched to the cooling operation mode.
When it is smaller than the second predetermined value set to be smaller than the first predetermined value, it is switched to the heating operation mode, and when it is between the first predetermined value and the second predetermined value, the dehumidifying operation mode is set. It can be switched to.

In this example, the dehumidifying operation mode is roughly divided into three modes between the cooling operation mode and the heating operation mode as follows (see FIG. 2).
-If the heat load received by the refrigeration cycle is relatively high, the outdoor heat exchanger 4 is used as a radiator as in the cooling operation mode, and the refrigerant flows in the same manner as in the cooling operation mode (first). In order to dissipate heat in two stages using the heat exchanger 2 and the passenger compartment outdoor heat exchanger 4 as radiators, a refrigerant is flowed in series with the first heat exchanger 2 and the passenger compartment outdoor heat exchanger 4. ), It is set to the dehumidifying / cooling operation mode (Series) in which the temperature of the dehumidified air is adjusted by adjusting the opening of the air mix door.
-If the heat load received by the refrigeration cycle is a medium heat load, only the first heat exchanger 2 is used as a radiator without using the outdoor heat exchanger 4, and the second Dehumidifying / heating operation mode (hereinafter, dehumidifying / heating operation mode) in which only the heat exchanger 3 of the above is used as a heat exchanger (a detour operation is performed in which the refrigerant from the first heat exchanger 2 is bypassed to flow through the vehicle compartment outdoor heat exchanger 4). (Called By-Pass)).
-If the heat load received by the refrigeration cycle is even lower at medium and low heat loads, two systems that use the passenger compartment outdoor heat exchanger 4 and the second heat exchanger 3 as heat exchangers in order to increase the heat absorption capacity. Dehumidifying and heating operation mode (hereinafter, dehumidifying and heating) that forms the flow of the above (performing parallel operation in which the refrigerant from the first heat exchanger 2 flows in parallel to the vehicle interior outdoor heat exchanger 4 and the second heat exchanger 3) It is set to the operation mode (called Parallel).

(About each operation mode)
In order to obtain each of the above operation modes, an expansion device (first expansion device (E-1) 12, second expansion device (E-2) 14), on-off valve (first refrigerant control unit 15, first The on-off valve 19) of No. 3, the second refrigerant control unit 17, and the damper 10 are set by the control unit 50 as follows.
In each operation mode, the blower 8 rotates according to the instruction from the control unit 50, the air that has passed through the inside / outside air switching device 6 is sent to the second heat exchanger 3, and then the first heat exchanger 2 Flow towards.

First, when the operation mode is set to the cooling operation mode, the control unit 50 fully opens the first expansion device (E-1) 12 and the second expansion device (E-1) 12 as shown in FIG. 1 (b). Squeeze the inflator (E-2) 14. Further, when the first and second refrigerant control units 15 and 17 are closed and the check valve 13 is replaced by the on-off valve 19, the on-off valve 19 is opened and the damper 10 is placed in the cooling position (opening 0%). (Position of, full cool position).

Then, as shown in FIG. 2, the compressed refrigerant discharged from the compressor 11 passes through the first heat exchanger 2 without radiating heat because there is no air passing through the first heat exchanger 2, and further expands to the first. Enter the vehicle interior heat exchanger 4 via the device 12. At this time, since the first expansion device 12 is in the fully open state, the high-temperature and high-pressure refrigerant discharged from the compressor 11 flows into the vehicle interior heat exchanger 4 and dissipates heat in the vehicle interior heat exchanger (). Condensed liquid). After that, the refrigerant radiated by the vehicle interior heat exchanger reaches the second expansion device 14 via the check valve 13 (or the on-off valve 19), is depressurized by the second expansion device 14, and is second. It enters the heat exchanger 3 of the above, and after being endothermic (evaporated and vaporized) there, it is returned to the compressor 11 via the accumulator 23.
Therefore, the air sent from the upstream side of the air conditioning unit 1 is cooled by the second heat exchanger 3, bypasses the first heat exchanger 2, and is supplied to the vehicle interior as it is as cold air.

When the operation mode is set to the dehumidifying / cooling operation mode (Series), the control unit 50 sets the position of the damper 10 and the first expansion device (E-1) as shown in FIG. 1 (b). Except for 12, the second expansion device (E-2), the refrigerant control unit, and the on-off valve are set in the same manner as in the cooling operation mode. That is, the first inflator (E-1) 12 is slightly squeezed, and the second inflator (E-2) 14 is squeezed. Further, when the first and second refrigerant control units 15 and 17 are closed and the check valve 13 is replaced by the on-off valve 19, the on-off valve 19 is opened. Then, the opening degree of the damper 10 is set to an arbitrary intermediate position.

Then, as shown in FIG. 2, the compressed refrigerant discharged from the compressor 11 is dissipated when passing through the first heat exchanger 2, and further, heat exchange outside the vehicle interior via the first expansion device 12. Enter vessel 4. At this time, since the first expansion device 12 is in a slightly squeezed state, it is slightly decompressed and expanded here to enter the vehicle interior heat exchanger 4, but heat is dissipated (condensed) by this vehicle interior heat exchanger. .. Further, since the first expansion device 12 is in a slightly throttled state, the pressure of the refrigerant in the first heat exchanger 2 is higher than in the fully opened state, and the heat dissipation force in the first heat exchanger 2 is increased. can do. After that, the refrigerant radiated by the vehicle interior heat exchanger reaches the second expansion device 14 via the check valve 13 (or the on-off valve 19), is depressurized by the second expansion device 14, and is second. It enters the heat exchanger 3 of the above, and after being endothermic (evaporated and vaporized) there, it is returned to the compressor 11 via the accumulator 23.
Therefore, the air sent from the upstream side of the air conditioning unit 1 is dehumidified by the second heat exchanger 3, heated when passing through the first heat exchanger 2, and used as dry cold air in the passenger compartment. Is supplied to.

Next, when the operation mode is set to the dehumidification / heating operation mode (By-Pass), the control unit 50 closes the first expansion device 12 and closes the first expansion device 12, as shown in FIG. 1 (b). When the second expansion device 14 is throttled, the first refrigerant control unit 15 is opened, the second refrigerant control unit 17 is closed, and the check valve 13 is replaced by the on-off valve 19, the on-off valve 19 is closed. , The opening degree of the damper 10 is set to an arbitrary intermediate position.

Then, the compressed refrigerant discharged from the compressor 11 is dissipated (condensed and liquefied) by the first heat exchanger 2, bypasses the vehicle interior heat exchanger 4, and flows through the first bypass flow path 16. It reaches the second expansion device 14, is depressurized by the second expansion device 14, and is supplied to the second heat exchanger 3. Then, after the heat is absorbed by the second heat exchanger 3, it is returned to the compressor 11 via the accumulator 23.
Therefore, the air sent from the upstream side of the air conditioning unit 1 is dehumidified by the second heat exchanger 3, heated when passing through the first heat exchanger 2, and used as dry warm air. It is supplied indoors.
The heating capacity in this dehumidifying / heating operation mode (By-Pass) is smaller than that in the dehumidifying / heating operation mode (parallel) described later.

When the operation mode is set to the dehumidification / heating operation mode (parallel), the control unit 50 throttles the first and second expansion devices 12 and 14 as shown in FIG. 1 (b), and the first and second expansion devices 12 and 14 are narrowed down. When the first and second refrigerant control units 15 and 17 are opened and the check valve 13 is replaced by the on-off valve 19, the on-off valve 19 is closed and the opening degree of the damper 10 is set to an arbitrary intermediate position. ..

Then, the compressed refrigerant discharged from the compressor 11 is radiated (condensed and liquefied) by the first heat exchanger 2, and then branched, and one of them passes through the first bypass flow path 16 and expands to the second. It reaches the device 14, where it is depressurized, absorbed (evaporated and vaporized) by the second heat exchanger 3, and then returned to the compressor 11 via the accumulator 23. At the same time, the other is decompressed by the first expansion device 12 to reach the vehicle interior heat exchanger 4, where heat is absorbed (evaporated and vaporized) and then passed through the second on-off valve 17 to pass the accumulator 23. It is returned to the compressor 11 via. Therefore, the air sent from the upstream side of the air conditioning unit 1 is dehumidified by the second heat exchanger 3, heated when passing through the first heat exchanger 2, and used as dry warm air. It is supplied indoors.

When the operation mode is set to the heating operation mode, the control unit 50 throttles the first expansion device 12 and closes the second expansion device 14, as shown in FIG. 1 (b). Further, when the first refrigerant control unit 15 is closed, the second refrigerant control unit 17 is opened, and the check valve 13 is replaced by the on-off valve 19, the on-off valve 19 is closed and the damper 10 is placed in the heating position. Set to (100% opening position, full hot position).

Then, the compressed refrigerant discharged from the compressor 11 is dissipated (condensed and liquefied) by the first heat exchanger 2, decompressed by the first expansion device 12, and reaches the vehicle interior heat exchanger 4, where heat is absorbed. After being (evaporated and vaporized), it is returned to the compressor 11 via the accumulator 23 through the second refrigerant control unit 17.
Therefore, the air sent from the upstream side of the air conditioning unit 1 passes through the second heat exchanger 3, but is not heat exchanged, and is all guided to the first heat exchanger 2 to be heated and warm air. It is supplied to the passenger compartment as.

In the above example, the dehumidifying / heating operation mode (Parallel) and the dehumidifying / heating operation mode (By-Pass) are set as the dehumidifying / heating operation mode. The difference (Tm-Tset) between the total signal (Tm) that takes into account the temperature of the vehicle interior air, the amount of solar radiation, etc. and the target blowout temperature (Tset) that takes into account the desired indoor temperature (Tset) set by the occupants. Although it is switched according to the size, only the dehumidifying / heating operation mode (Parallel) may be used as the dehumidifying / heating operation mode.

By the way, in the above configuration, when the operation mode is the dehumidifying / cooling (Series) operation mode or the cooling operation mode, the refrigerant is not passed through the first bypass flow path 16 or the second bypass flow path 18. When switching from this operation mode to the operation mode in which the refrigerant flows through either one or both of the first and second bypass flow paths 16 and 18, the refrigerant flows through the bypass flow path that has not flowed until now. Therefore, if the pressure difference between the inflow side and the outflow side of the bypass flow path is large, a high-pressure refrigerant (or an intermediate-pressure refrigerant) will pass through the bypass flow path when the refrigerant control units 15 and 17 are opened. Inflows to the low pressure side at once, and there is an inconvenience that a sudden sound is generated.
Therefore, by controlling the operating state of the second refrigerant control unit 17 as a throttle valve as described above, the pressure difference between the front and rear of the first refrigerant control unit 15 and the pressure difference between the front and rear of the second refrigerant control unit 17 can be obtained. After making it smaller, the refrigerant control units 15 and 17 are opened.

(About switching the operation mode)
Hereinafter, the control for switching the operation mode will be described for each switching mode.
First, as shown in FIG. 3, when switching from the dehumidifying / cooling (Series) operation mode to the dehumidifying / heating (Parallel) operation mode, that is, the vehicle interior heat exchanger 4 is used as a radiator, and the first bypass flow path is used. From the operation mode in which the refrigerant is not passed through the second bypass flow path, the vehicle interior heat exchanger 4 is used as a heat absorber to allow the refrigerant to flow through the first bypass flow path and the second bypass flow path. A case of switching to the operation mode will be described.

When switching from the dehumidifying / cooling (Series) operation mode to the dehumidifying / heating (Parallel) operation mode, the first refrigerant control valve 15 is opened, the first expansion device 12 is throttled, and the vehicle interior heat exchanger 4 is used as a heat exchanger. However, in the dehumidifying / cooling (Series) operation mode, the refrigerant pressure state in the first heat exchanger 2 is maintained high and the first heat exchanger is opened. In order to increase the heat dissipation capacity of 2, the first expansion device 12 is in a slightly throttled state. Therefore, a pressure difference is not a little generated between the refrigerant on the upstream side and the refrigerant on the downstream side of the first expansion device 12, so that when the first refrigerant control unit 15 is opened in this state, the high-pressure refrigerant is used. Flows into the low pressure side at once through the first bypass flow path 16 and flows into the second expansion device 14. Therefore, there is an inconvenience that a sudden sound is generated when the refrigerant suddenly flows into the second expansion device 14.
Therefore, the control unit 50 controls the refrigerant control units 15 and 17, the on-off valves 19, and the expansion devices 12 and 15 to dehumidify and heat the dehumidifying and cooling (Series) operation modes in the order shown in FIG. Parallel) Switch to operation mode.

First, from the state of the dehumidifying / cooling (Series) operation mode shown in FIG. 4A, the second refrigerant control unit 17 is set to the throttled state, and a part of the refrigerant that has passed through the vehicle interior heat exchanger 4 is seconded. It is guided to the compressor 11 via the bypass flow path 18 (first stage: FIG. 4 (b)). That is, a small amount of the refrigerant having an intermediate pressure downstream of the vehicle interior heat exchanger 4 is supplied between the second heat exchanger 3 and the compressor 11. Here, when the second refrigerant control unit 17 is fully opened and the refrigerant suddenly flows into the second bypass flow path 18, the intermediate pressure refrigerant from the first expansion device 12 to the second expansion device 14 becomes low pressure. Since it suddenly flows into the refrigerant flow path between the second heat exchanger 3 and the compressor 11 (in the case of this embodiment having the accumulator 23, the intermediate pressure refrigerant suddenly flows into the accumulator 23). Therefore, an abnormal noise is generated, and the internal pressure of the second heat exchanger 3 rises sharply, resulting in inconveniences such as a decrease in the heat absorption capacity of the second heat exchanger 3. Therefore, in the first stage, by flowing a small amount of refrigerant through the second bypass flow path 18, the pressure on the downstream side of the second refrigerant control unit 17 is not impaired in the endothermic capacity of the second heat exchanger 3. A little higher.

After that, the first expansion device 12 which has been narrowed down a little until now is fully opened (second stage: FIG. 4C). As a result, the high-pressure refrigerant on the upstream side of the first expansion device 12 is guided to the second expansion device 14 and the second refrigerant control unit 17 via the vehicle interior heat exchanger 4, so that the first heat exchanger The pressure difference between the refrigerant flow path between the 2 and the first expansion device 12 and the refrigerant flow path between the vehicle interior heat exchanger 4 and the second expansion device 14 is set to be substantially the same. ..

Then, the first refrigerant control unit 15 is opened to allow the high-pressure refrigerant to flow through the first bypass flow path 16 (third stage: FIG. 4D). At this point, the refrigerant flow path between the first heat exchanger 2 and the first expansion device 12 and the refrigerant flow path between the passenger compartment outdoor heat exchanger 4 and the second expansion device 14 Since the pressure difference is almost eliminated, the inconvenience that the high-pressure refrigerant suddenly flows into the low-pressure side is avoided.

After that, the first expansion device 12 is squeezed to make the vehicle interior heat exchanger 4 function as a heat absorber (fourth stage: FIG. 4 (e)). As a result, the pressure difference between the upstream side and the downstream side of the second refrigerant control unit is reduced.
Finally, the second refrigerant control unit 15 is fully opened, and the low-pressure refrigerant that has passed through the vehicle interior heat exchanger 4 is returned to the compressor 11 via the second bypass flow path 18 (fifth stage: FIG. 4 (f). )).
Therefore, since the pressure difference between the upstream side and the downstream side of the second refrigerant control unit 17 is reduced in the fourth stage, even if the second bypass flow path 18 is subsequently opened (fifth stage), it is intermediate. The inconvenience that the pressure refrigerant suddenly flows into the low pressure side is avoided.

Therefore, the operation mode can be switched from the dehumidifying / cooling (Series) operation mode to the dehumidifying / heating (Parallel) operation mode through the above stages, so that it is possible to suppress the generation of noise and switch without stopping the compressor. Is possible.

It is conceivable that the order of switching may be different from this. That is, the first expansion device 12 in a slightly throttled state is placed before the first stage in which the closed second refrigerant control unit 17 is opened to allow the refrigerant to flow through the second bypass flow path 18. This is a switching mode in which the second stage of reducing the pressure difference between the upstream side and the downstream side of the first refrigerant control unit 15 is carried out as fully open. When the first expansion device 12 is opened, the pressure of the refrigerant in the first heat exchanger 2 decreases, and the heating capacity temporarily decreases. Therefore, in order to improve the heating capacity from the dehumidifying / cooling (Series) operation mode. When switching to the dehumidifying / heating (Parallel) operation mode, it is desired to shorten the time for fully opening the first expansion device 12. Therefore, as already described, it is preferable that the order of the first stage and the second stage is not reversed.

Next, as shown in FIG. 5, when switching from the dehumidifying / cooling (Series) operation mode to the dehumidifying / heating (By-Pass) operation mode, that is, the vehicle interior heat exchanger 4 is used as a radiator and the first bypass is used. From the operation mode in which the refrigerant is not passed through the flow path and the second bypass flow path, the refrigerant is passed only through the first bypass flow path without using the heat exchange function by the vehicle interior heat exchanger 4. A case of switching to the operation mode will be described.

To switch from the dehumidifying / cooling (Series) operation mode to the dehumidifying / heating (By-Pass) operation mode, the first refrigerant control valve 15 may be opened and the first expansion device 12 may be closed. In the (Series) operation mode, since the first expansion device 12 is in a slightly throttled state as described above, there is not a little space between the refrigerant on the upstream side and the refrigerant on the downstream side of the first expansion device 12. There is a pressure difference. Therefore, when the first refrigerant control unit 15 is opened in this state, the high-pressure refrigerant flows at once to the low-pressure side through the first bypass flow path 16 and flows into the second expansion device 14, causing a sudden sound. There is an inconvenience. Therefore, the control unit 50 controls the refrigerant control units 15 and 17, the on-off valves 19, and the expansion devices 12 and 14 to dehumidify and heat (By) the dehumidifying and cooling (Series) operation modes in the order shown in FIG. -Pass) Switch to operation mode.

Here, the first stage (FIG. 6 (b)) to the third stage (FIG. 6 (d)) are the first stage (FIG. 4 (b)) to the third stage (FIG. 4 (d)) of FIG. ) Is sequentially performed, and then the first expansion device 12 is closed to block the flow to the vehicle interior heat exchanger 4 (sixth stage: FIG. 4 (e)).

As a result, the pressure difference between the upstream side and the downstream side of the first refrigerant control unit 16 is gradually reduced by the first and second stages, so that the first refrigerant control unit 15 is opened (third stage). However, the inconvenience that the high-pressure refrigerant suddenly flows into the low-pressure side is avoided. Further, a dehumidifying / heating (By-Pass) operation mode in which the refrigerant does not flow through the second bypass flow path 18 can be realized by the sixth stage following the first to third stages.
Therefore, the operation mode can be switched from the dehumidifying / cooling (Series) operation mode to the dehumidifying / heating (By-Pass) operation mode through the above stages, so that it is possible to suppress the generation of noise and without stopping the compressor. It becomes possible to switch. In the above example, the second refrigerant control unit 17 may be further closed at the same time as the sixth stage or after the sixth stage to eliminate the possibility of the refrigerant flowing back.

Next, as shown in FIG. 7, when switching from the dehumidifying / cooling (Series) operation mode to the heating operation mode, that is, using the vehicle interior heat exchanger 4 as a radiator, the first bypass flow path and the second A case of switching from an operation mode in which the refrigerant is not passed through the bypass flow path to an operation mode in which the refrigerant is passed only through the second bypass flow path by using the vehicle interior heat exchanger 4 as a heat exchanger will be described.

To switch from the dehumidifying / cooling (Series) operation mode to the heating operation mode, the second refrigerant control valve 17 may be opened and the first expansion device 12 may be throttled. However, in the dehumidifying / cooling (Series) operation mode, Although the first expansion device 12 is in a slightly throttled state as described above, the refrigerant that has passed through the vehicle interior outdoor heat exchanger 4 is in a relatively high pressure state, so that the second refrigerant control unit 17 When is suddenly opened, the refrigerant of intermediate pressure on the upstream side of the second expansion device 14 suddenly flows into the refrigerant flow path between the second heat exchanger 3 and the compressor 11 (this implementation with the accumulator 23). In the form, an intermediate pressure refrigerant suddenly flows into the accumulator 23), which may cause abnormal noise.
Therefore, the control unit 50 controls the refrigerant control units 15 and 17, the on-off valves 19, and the expansion devices 12 and 14 to change the dehumidifying / cooling (Series) operation mode to the heating operation mode in the order shown in FIG. Switch.

First, from the state of the dehumidifying / cooling (Series) operation mode shown in FIG. 8A, the first expansion device 12 is squeezed to make the vehicle interior heat exchanger 4 function as a heat absorber and the first expansion device 12 The pressure on the downstream side of the is reduced (7th stage: FIG. 8 (b)).
However, immediately after the vehicle interior outdoor heat exchanger 4 is made to function as a heat absorber in this 7th stage, the pressure on the downstream side of the passenger compartment outdoor heat exchanger 4 is not necessarily sufficiently lowered. With the refrigerant control unit 17 of No. 2 in the throttled state, a part of the refrigerant that has passed through the vehicle interior heat exchanger 4 is guided to the compressor 11 via the second bypass flow path 18 (8th stage: FIG. 8C). ), The pressure difference between the front and rear of the second refrigerant control unit 17 is reduced while further reducing the pressure of the intermediate pressure refrigerant, and the inconvenience that the medium and high pressure refrigerant suddenly flows into the suction side (accumulator 23) of the compressor 11. To avoid.

After that, the second expansion device 14 is closed to block the flow to the second heat exchanger 3, and the second refrigerant control unit 17 is fully opened to reduce the pressure difference before and after the second refrigerant control 17. Eliminate (9th stage: Fig. 8 (d)).
Therefore, since the operation mode can be switched from the dehumidifying / cooling (Series) operation mode to the heating operation mode through the above stages, the operation mode can be switched without generating noise and without stopping the compressor 11. It will be possible.

Even if the operations of closing the second expansion device 14 to block the flow to the second heat exchanger 3 and fully opening the second refrigerant control unit 17 are performed at the same time, there is a slight time lag. May be provided. When a time difference is provided, it is preferable that the second refrigerant control unit 17 performs the fully open operation first, and then the second expansion device 14 fully closes. When the operation procedure is reversed and the second expansion device 14 is fully closed first, the compressor 11 to the first heat exchanger 2, the first expansion device 12, and the passenger compartment outdoor heat exchanger 4 are moved. The refrigerant flowing in order is dammed up by the second refrigerant control unit 17 that is completely closed, the intermediate pressure on the upstream side of the second refrigerant control unit 17 rises unnecessarily, and the driving power of the compressor increases. It is not preferable from the viewpoint of power saving. Therefore, by fully opening the second refrigerant control unit 17 first, it is possible to switch the operation mode while preventing the refrigerant pressure from rising.

When switching from the cooling operation mode in which the vehicle interior heat exchanger 4 is used as a radiator to the operation mode in which the vehicle interior heat exchanger 4 is used as a heat absorber, the operation mode is switched according to the procedure described above to suppress the generation of noise. It is also possible to quickly switch the operation mode without stopping the compressor.

In addition, in the above form, it may be changed as appropriate within the range which does not deviate from the object of this invention. For example, the difference between the heat load received by the refrigeration cycle 100 and the target blowing temperature is used as an index for switching the operation mode of the refrigeration cycle. However, as a representative of the heat load received by the refrigeration cycle 100, the outside air is used. The temperature may be used, or the cooling temperature of the second heat exchanger 3 or the like may be used.

1 Air conditioning unit 2 1st heat exchanger 3 2nd heat exchanger 4 Outdoor heat exchanger 11 Compressor 12 1st expansion device 13 Check valve 14 2nd expansion device 15 1st refrigerant control unit 16 1st bypass flow path 17 2nd refrigerant control unit 18 2nd bypass flow path 19 On-off valve 100 Refrigeration cycle

Claims (7)

The compressor (11), the first heat exchanger (2) arranged in the air conditioning unit (1) and the ventilation amount is adjusted by the damper (10), and the first heat exchanger (2) arranged in the air conditioning unit (1). A second exchanger (3) arranged upstream of the first heat exchanger (2) in the air conditioning unit (1) and an outdoor heat exchanger (4) capable of exchanging heat with the outside air. ), A first expansion device (12) capable of narrowing and opening and closing the refrigerant flow path, and a second expansion device (14) capable of narrowing and closing the refrigerant flow path. And
The compressor (11), the first heat exchanger (2), the first inflator (12), the outdoor heat exchanger (4), the second inflator (14), and the above. Connect the second heat exchanger (3) in a loop at least in this order.
The refrigerant flow path between the first heat exchanger (2) and the first expansion device (12), and the vehicle interior heat exchanger (4) and the second expansion device (14). The refrigerant flow path between them is connected via a first bypass flow path (16) that can be opened and closed by the first refrigerant control unit (15).
Of the refrigerant flow paths between the vehicle interior heat exchanger (4) and the second expansion device (14), on the upstream side of the merging portion (A) with the first bypass flow path (16). A backflow blocking section (13, 19) that blocks the flow of the refrigerant from the merging portion (A) to the upstream side is provided, and the vehicle interior heat exchanger (4) and the backflow blocking section (13, 19) are provided. A second bypass provided with a second refrigerant control unit (17) for the refrigerant flow path between the refrigerant flow paths and the refrigerant flow path between the second heat exchanger (3) and the compressor (11). In a vehicle air conditioner having a refrigeration cycle connected via a flow path (18),
A vehicle air conditioner comprising the second refrigerant control unit (17) with a throttle valve capable of throttle and open / close the second bypass flow path (18). A control means (50) for switching and controlling the operation mode of the refrigeration cycle (100) is further provided.
The control means (50) passes the refrigerant discharged from the compressor (11) through the first heat exchanger (2) without radiating heat or exchanging heat, and then the first expansion. The device (12) decompresses the pressure as necessary, and the vehicle interior heat exchanger (4) dissipates heat. The dissipated refrigerant is further depressurized by the second expansion device (14), and then the first. From the first operation mode in which heat is absorbed by the heat exchanger (3) of 2, the refrigerant discharged from the compressor (11) is dissipated by the first heat exchanger (2), and then the first After passing through the bypass flow path (16) and depressurizing with the second inflator, the heat is absorbed by the second heat exchanger and depressurized by the first inflator (12). In switching to the second operation mode in which heat is absorbed by the vehicle interior heat exchanger (4), and then the second bypass flow path is passed through and returned to the compressor (11).
From the state of the first operation mode, the second refrigerant control unit (17) is set to the throttled state, and a part of the refrigerant that has passed through the vehicle interior heat exchanger (4) is passed through the second bypass flow path (18). The first stage leading to the compressor (11) via)
A second stage in which the first expansion device (12) is fully opened, and
A third stage in which the first refrigerant control unit (15) is opened and the refrigerant that has passed through the first heat exchanger (2) is also passed through the first bypass flow path (16).
A fourth stage in which the first expansion device (12) is squeezed to make the vehicle interior heat exchanger (4) function as an endothermic device.
A fifth stage in which the second refrigerant control unit (17) is fully opened, and
The vehicle air conditioner according to claim 1, wherein the air conditioner is sequentially switched. A control means (50) for switching and controlling the operation mode of the refrigeration cycle (100) is further provided.
The control means (50) passes the refrigerant discharged from the compressor (11) through the first heat exchanger (2) without radiating heat or exchanging heat, and then the first expansion. The device (12) decompresses the pressure as necessary, and the vehicle interior heat exchanger (4) dissipates heat. The dissipated refrigerant is further decompressed by the second expansion device (14), and then the second expansion device (14) is used. From the first operation mode in which heat is absorbed by the heat exchanger (3) of 2, the refrigerant discharged from the compressor (11) is dissipated by the first heat exchanger (2), and then the first In switching to the third operation mode in which only the bypass flow path (16) of the above is passed, the pressure is reduced by the second expansion device (14), and then the heat is absorbed by the second heat exchanger (3).
From the state of the first operation mode, the second refrigerant control unit (17) is set to the throttled state, and a part of the refrigerant that has passed through the vehicle interior heat exchanger (4) is passed through the second bypass flow path (18). The first stage leading to the compressor (11) via)
A second stage in which the first expansion device (12) is fully opened, and
A third stage in which the first refrigerant control unit (15) is opened and the refrigerant that has passed through the first heat exchanger (2) is also passed through the first bypass flow path (16).
A sixth stage in which the first expansion device (12) is closed to block the flow to the vehicle interior heat exchanger (4), and
The vehicle air conditioner according to claim 1, wherein the air conditioner is sequentially switched. A control means (50) for switching and controlling the operation mode of the refrigeration cycle (100) is further provided.
The control means (50) passes the refrigerant discharged from the compressor (11) through the first heat exchanger (2) without radiating heat or exchanging heat, and then the first expansion. The device (12) decompresses the pressure as necessary, and the vehicle interior heat exchanger (4) dissipates heat. The dissipated refrigerant is further depressurized by the second expansion device (14), and then the first. From the first operation mode in which heat is absorbed by the heat exchanger (3) of 2, the refrigerant discharged from the compressor (11) is dissipated by the first heat exchanger (2), and then the first The pressure is reduced by the expansion device (12) of the above, the heat is absorbed by the vehicle interior heat exchanger (4), and the refrigerant that has passed through the vehicle interior heat exchanger (4) is passed through the second bypass flow path (18). In switching to the fourth operation mode for returning to the compressor (11).
From the state of the first operation mode, the seventh stage in which the first expansion device (12) is squeezed to make the vehicle interior heat effector (4) function as a heat absorber, and
With the second refrigerant control unit (17) in the throttled state, a part of the refrigerant that has passed through the vehicle interior heat exchanger (4) is passed through the second bypass flow path (18) to the compressor (11). The 8th stage leading to
A ninth stage in which the second expansion device (14) is closed to block the flow to the second heat exchanger (3) and the second refrigerant control unit (17) is fully opened.
The vehicle air conditioner according to claim 1, wherein the air conditioner is sequentially switched. Using the vehicle air conditioner according to claim 1, the refrigerant discharged from the compressor (11) is passed through the first heat exchanger (2) without being dissipated or heat exchanged, and then the refrigerant is passed through. The first expansion device (12) decompresses the pressure as necessary, and the vehicle interior heat exchanger (4) dissipates heat, and the dissipated refrigerant is further depressurized by the second expansion device (14). After that, from the first operation mode in which heat is absorbed by the second heat exchanger (3), the refrigerant discharged from the compressor (11) is dissipated by the first heat exchanger (2). , The first bypass flow path (16) is passed through, the pressure is reduced by the second expansion device, and then heat is absorbed by the second heat exchanger, and the first expansion device (12) absorbs heat. Operation mode switching control to switch to the second operation mode in which the heat is absorbed by the vehicle interior heat exchanger (4) after the pressure is reduced, and then the second bypass flow path is passed through and returned to the compressor (11). In the method
From the state of the first operation mode, the second refrigerant control unit (17) is set to the throttled state, and a part of the refrigerant that has passed through the vehicle interior heat exchanger (4) is passed through the second bypass flow path (18). The first step leading to the compressor (11) via)
After the first step, a second step of fully opening the first expansion device (12) and
After the second step, the first refrigerant control unit (15) is opened to allow the refrigerant that has passed through the first heat effector (2) to flow through the first bypass flow path (16). 3 steps and
After the third step, a fourth step of squeezing the first expansion device (12) to make the vehicle interior heat exchanger (4) function as a heat absorber,
The fifth step of fully opening the second refrigerant control unit (17) and
An operation mode switching method characterized by being provided with. Using the vehicle air conditioner according to claim 1, the refrigerant discharged from the compressor (11) is passed through the first heat exchanger (2) without being dissipated or heat exchanged, and then the refrigerant is passed through. The first expansion device (12) decompresses the pressure as necessary, and the vehicle interior heat exchanger (4) dissipates heat, and the dissipated refrigerant is further depressurized by the second expansion device (14). After that, from the first operation mode in which heat is absorbed by the second heat exchanger (3), the refrigerant discharged from the compressor (11) is dissipated by the first heat exchanger (2). In the third operation mode, only the first bypass flow path (16) is allowed to flow, the pressure is reduced by the second expansion device (14), and then heat is absorbed by the second heat exchanger (3). In the switching operation mode switching control method,
From the state of the first operation mode, the second refrigerant control unit (17) is set to the throttled state, and a part of the refrigerant that has passed through the vehicle interior heat exchanger (4) is passed through the second bypass flow path (18). The first step leading to the compressor (11) via)
After the first step, a second step of fully opening the first expansion device (12) and
After the second step, the first refrigerant control unit (15) is opened to allow the refrigerant that has passed through the first heat effector (2) to flow through the first bypass flow path (16). 3 steps and
After the third step, a sixth step of closing the first expansion device (12) to block the flow to the vehicle interior heat exchanger (4), and the sixth step.
An operation mode switching method characterized by being provided with. Using the vehicle air conditioner according to claim 1, the refrigerant discharged from the compressor (11) is passed through the first heat exchanger (2) without being dissipated or heat exchanged, and then the refrigerant is passed through. The first expansion device (12) decompresses the pressure as necessary, and the vehicle interior heat exchanger (4) dissipates heat, and the dissipated refrigerant is further depressurized by the second expansion device (14). After that, from the first operation mode in which heat is absorbed by the second heat exchanger (3), the refrigerant discharged from the compressor (11) is dissipated by the first heat exchanger (2). , The pressure is reduced by the first expansion device (12), heat is absorbed by the vehicle interior heat exchanger (4), and the refrigerant that has passed through the vehicle interior heat exchanger (4) is passed through the second bypass flow path (4). In the operation mode switching control method of switching to the fourth operation mode of returning to the compressor (11) via 18),
From the state of the first operation mode, the seventh step of narrowing down the first expansion device (12) to make the vehicle interior heat effector (4) function as an endothermic device.
After the seventh step, with the second refrigerant control unit (17) in the throttled state, a part of the refrigerant that has passed through the vehicle interior heat exchanger (4) is passed through the second bypass flow path (18). Eighth step leading to the compressor (11) through
After the eighth step, the second expansion device (14) is closed to block the flow to the second heat exchanger (3), and the second refrigerant control unit (17) is fully opened. 9th step to do and
An operation mode switching method characterized by being provided with.

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