JP2021146958A - Vehicle air conditioner and operation mode switching control method - Google Patents

Abstract

To reduce the noise generated when switching between a heating operation that does not allow refrigerant to flow through an evaporator and a dehumidifying heating operation that allows the refrigerant to flow through.SOLUTION: In vehicle air conditioners equipped with refrigeration cycles, a compressor 11, a first heat exchanger 2, a first inflator 12, a passenger compartment outdoor heat exchanger 4, a second inflator 14, and a second heat exchanger 3 are connected in this order in a loop. The connection is made via a first bypass flow path 16 provided with a first refrigerant control unit 15 between the first heat exchanger 2 and the first inflator 12 and between the passenger compartment outdoor heat exchanger 4 and the second inflator 14. A backflow blocking unit 13 is provided on the downstream side of the passenger compartment outdoor heat exchanger 4 between the passenger compartment outdoor heat exchanger and the merging portion with the first bypass flow path 16. The connection is made via a second bypass flow path 18 provided with the second refrigerant control unit 17 between the passenger compartment outdoor heat exchanger 4 and the backflow blocking unit 13 and between the second heat exchanger 3 and the compressor 11. The second expansion device 14 is closed to switch to the heating operation, and the second inflator 14 is closed to switch to the dehumidifying heating operation.SELECTED DRAWING: Figure 3

Description

The present invention relates to a vehicle air conditioner provided with a refrigeration cycle capable of switching an operation mode between a heating operation and a dehumidifying heating operation, and particularly generates noise when switching an operation mode between a heating operation and a dehumidifying heating operation. The present invention relates to a vehicle air conditioner and an operation mode switching method capable of reducing the number of vehicles.

Conventionally, there is known an air conditioner for a vehicle that not only cools or heats the interior of a vehicle with a heat pump type refrigeration cycle but also enables dehumidifying operation.
For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2014-094671), a first heat exchanger (radiator 4), which is arranged in an air conditioning unit and whose ventilation amount is adjusted by a damper (air mix damper 28), is described in Patent Document 1 (Japanese Patent Laid-Open No. 2014-094671). ), The first expansion device (outdoor expansion valve 6), the vehicle outdoor heat exchanger (outdoor heat exchanger 7) capable of exchanging heat with the outside air, and the second expansion device (indoor expansion valve 8). At least in this order, the second heat exchanger (heat exchanger 9) arranged in the air conditioning unit and arranged upstream of the first heat exchanger (radiator 4) in the air flow direction in the air conditioning unit. A refrigeration cycle connected in a loop is provided, and the refrigeration cycle includes a refrigerant flow path between the first heat exchanger (radiator 4) and the first expansion device (outdoor expansion valve 6), and the outside of the vehicle interior. A first bypass provided with a first refrigerant control unit (electromagnetic valve 22) for the refrigerant flow path between the heat exchanger (outdoor heat exchanger 7) and the second expansion device (indoor expansion valve 8). Of the refrigerant flow paths connected via the flow path (fluident pipe 13F) and between the vehicle outdoor heat exchanger (outdoor heat exchanger 7) and the second expansion device (indoor expansion valve 8), the first The second refrigerant is formed between the refrigerant flow path on the upstream side of the confluence with the bypass flow path (fluid pipe 13F) of No. 1 and the refrigerant flow path between the second heat exchanger (heat exchanger 9) and the compressor. A heat pump cycle connected via a second bypass flow path (fluid pipe 13D) provided with a control unit (electromagnetic valve 21) is disclosed.

Then, the operation mode is switched according to the outside temperature, and particularly in an environment where the outside temperature is around 0 ° C., the refrigerant discharged from the compressor is subjected to the first, with the threshold value provided in the vicinity as a boundary. The heat is dissipated by the heat exchanger (radiator 4), and the radiated refrigerant is branched. In the dehumidifying and heating operation in which heat is absorbed by the heat exchanger, the refrigerant discharged from the compressor is radiated by the first heat exchanger (radiator 4), and the radiated refrigerant is not branched, but is decompressed and then outside the vehicle interior. It is switched to heating operation, which absorbs heat with a heat exchanger.

However, the operation mode is dehumidification in which the refrigerant is passed from the heating operation in which the refrigerant is not passed through the second heat exchanger (heat exchanger 9) arranged in the air conditioning unit to the second heat exchanger (heat exchanger 9). When switching to the heating operation, the high-pressure refrigerant that has passed through the first heat exchanger (radiator 4) flows into the second expansion device (indoor expansion valve 8) at once through the first bypass passage, so that it suddenly occurs. There is an inconvenience of generating a strange noise.

In order to deal with such inconvenience, when switching the operation mode, the compressor is temporarily stopped, the refrigerant circuit on the high pressure side of the discharge side of the compressor is switched below the reference value, and then the refrigerant circuit is switched again. It is also conceivable to adopt a method of operating the compressor (see Patent Document 2).

Japanese Unexamined Patent Publication No. 2014-094671 Japanese Unexamined Patent Publication No. 2012-250708

However, when switching the refrigerant circuit, if the compressor is temporarily stopped and the refrigerant circuit is switched after the high-pressure side refrigerant pressure on the discharge side of the compressor falls below the reference value, every time the operation mode of the refrigeration cycle is switched. It is necessary to stop the compressor, and the pressure cannot be switched until the pressure on the discharge side of the compressor drops below the reference value. Moreover, 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 when switching the operation mode of the refrigeration cycle between the heating operation and the dehumidifying heating operation, without generating noise and without stopping the compressor. The main task is to provide an air conditioner for vehicles that can be switched and an operation mode switching method using the air conditioner for vehicles.

In order to achieve the above object, the vehicle air conditioner according to the present invention includes a refrigeration cycle (100) and a control means (50) for switching and controlling the operation mode of the refrigeration cycle (100).
The refrigeration cycle (100)
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 on the upstream side in the air conditioning unit (1) with respect to the first heat exchanger (2), 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. death,
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.
Between the refrigerant flow path between the first heat exchanger (2) and the first expansion device (12) and between the vehicle interior heat exchanger (4) and the second expansion device (14). Is connected to the refrigerant flow path of the above 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 portion (13) that blocks the flow of the refrigerant from the merging portion (A) to the upstream side is provided, and the refrigerant flow between the vehicle interior heat exchanger (4) and the backflow blocking portion (13). A second bypass flow path (18) provided with a second refrigerant control unit (17) for the refrigerant flow path between the path, the second heat exchanger (3), and the compressor (11). Connect via
The control means (50) is
The refrigerant discharged from the compressor (11) is dissipated by the first heat exchanger (2), and the dissipated refrigerant is depressurized by the first expansion device (12), and then the outside heat of the passenger compartment is generated. A heating operation in which heat is absorbed by the exchanger (4) and then returned to the compressor (11) via the second bypass passage (18) without passing through the second heat exchanger (3). When,
The refrigerant discharged from the compressor (11) is radiated by the first heat exchanger (2), and the radiated refrigerant is branched, while passing through the first bypass passage (16). After depressurizing with the second inflator (14), heat is absorbed through the second heat exchanger (3), and on the other hand, after depressurizing with the first inflator (12), the outdoor heat exchanger is used. A dehumidifying / heating operation in which heat is absorbed in (4) and returned to the compressor (11) via the second bypass passage (18).
Can be switched,
The control means (50) switches from the dehumidifying heating operation to the heating operation by switching the second expansion device (14) from the throttle state to the closed state when switching between the heating operation and the dehumidifying heating operation. It is characterized by having a first switching means and a second switching means for switching from the heating operation to the dehumidifying heating operation by switching the second expansion device (14) from the closed state to the throttle state.

Therefore, in the vehicle air conditioner equipped with the above-mentioned heat pump cycle, the heating operation and the dehumidifying heating operation are switched by switching the second expansion device between the closed state and the throttle state. It is possible to keep the high-pressure refrigerant constantly supplied to the inflow side of the second expansion device, and even when the heating operation is switched to the dehumidifying heating operation, the pressure acting on the second expansion device changes abruptly. (The high-pressure refrigerant does not suddenly flow into the second expansion device), and it is possible to avoid the generation of noise at the time of switching.

Here, as a means for constantly supplying the high-pressure refrigerant to the inflow side of the second expansion device before and after the switching, when the control means (50) switches between the heating operation and the dehumidifying heating operation, the first refrigerant control unit ( It is advisable to keep 15) open.
By keeping the first refrigerant control unit in the open state when switching the operation mode between the heating operation and the dehumidifying heating operation, even if the operation mode is switched between the heating operation and the dehumidifying heating operation, the first refrigerant Since there is no pressure difference between the front and back of the control unit (because the high-pressure refrigerant can be constantly supplied to the inflow side of the second expansion device before and after switching the operation mode), dehumidification is performed from the heating operation. When switching to the heating operation, it is possible to avoid the inconvenience that the high-pressure refrigerant flows into the second expansion device at once.

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. By switching the second inflator from the throttled state to the closed state, the dehumidifying and heating operation is switched to the heating operation, and by switching the second inflator from the closed state to the throttled state, the heating operation is switched to the dehumidifying and heating operation. Therefore, it is possible to keep the high-pressure refrigerant constantly supplied to the inflow side of the second expansion device before and after the switching, and even when the operation mode is switched between the heating operation and the dehumidifying heating operation, the noise is generated. It is possible to prevent the occurrence.
Further, since the operation mode can be switched between the heating operation and the dehumidifying heating operation without stopping the compressor, it is possible to shorten the time until the switching.

FIG. 1 shows a configuration 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 an expansion device, a refrigerant control unit, an on-off valve, and a damper. It is a table which showed the state for 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 illustrating switching control between dehumidifying and heating (Parallel) operation and heating operation, and more specifically, a second expansion device with the second refrigerant control unit maintained in an open state. The figure illustrates the control of switching from the dehumidifying heating operation to the heating operation by switching from the throttle state to the closed state, and switching from the heating operation to the dehumidification heating operation by switching the second expansion device from the closed state to the throttle state. be. In the figure, the path filled with the high-pressure refrigerant is shown by a thick solid line, and the path filled with the low-pressure refrigerant is shown by a thick broken line.

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, wherein 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 vehicle interior heat exchanger 4 which is arranged outside the air conditioning unit 1 and can exchange 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 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 that opens and closes the first bypass flow path 16, and the second refrigerant control unit (V-2) 17 is a second. It is composed of an on-off valve that opens and closes the bypass flow path 18 of the above.

The operation of the first and second expansion devices 12 and 14, the opening and closing of the first and second refrigerant control units 15 and 17 and the on-off valve 19, the opening of the damper 10, and the discharge amount of the compressor 11 are controlled by means for controlling. It is controlled by a control signal from 50 (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. The outside temperature signal from the outside air temperature sensor 51 that detects the temperature (outside temperature), the inside temperature signal from the inside air temperature sensor 52 that detects the vehicle interior temperature, the solar radiation amount signal from the solar radiation sensor 53 that detects the amount of solar radiation, and operation. Various signals from the operation unit that sets the mode and the like are input, and these various signals are processed according to a predetermined program.

In this example, 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) is the state of the heat load received by the refrigeration cycle (change of the operating state of the damper). The difference (Tm-) between the total signal (Tm) that takes into account the temperature of the outside air inside the vehicle, the temperature of the air inside the vehicle, the amount of solar radiation, etc. It is switched according to the size of Tset) as shown in FIG.

Further, in this example, the dehumidifying operation mode is roughly divided into three modes between the cooling operation mode and the heating operation mode (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. ), Set to the dehumidifying / cooling operation mode (Series) that adjusts the temperature of the dehumidified air 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) uses only the heat exchanger 3 of (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 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 liquefaction). 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, and a part of the air is heated when passing through the first heat exchanger 2, and the dry cold air is dried. It is supplied to the passenger compartment as.

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 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, and a part of the air is heated when passing through the first heat exchanger 2, and the temperature becomes dry. It is supplied to the passenger compartment as wind.
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). 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 dissipated (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, and a part of the air is heated when passing through the first heat exchanger 2, and the temperature becomes dry. It is supplied to the passenger compartment as wind.

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 air inside the vehicle, the amount of solar radiation, etc., and the target blowout temperature (Tset) that takes into account the desired room 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, in all the operation modes except the heating operation, the refrigerant is supplied to the second heat exchanger 3 to dehumidify or cool the air passing through the second heat exchanger 3. There is. On the other hand, in the heating operation, the supply of the refrigerant to the second heat exchanger 3 is stopped, and the air sucked into the air conditioning unit is heated to the maximum. Therefore, conventionally, when the operation mode is set to the heating operation mode, the first expansion device 12 is throttled, the first refrigerant control unit 15 is closed, the second refrigerant control unit 17 is opened, and vice versa. When the on-off valve 13 is used as a substitute for the stop valve 13, the on-off valve 19 is closed and the damper 10 is set to the heating position (position of 100% opening, full hot position).
As a result, 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. After being absorbed (evaporated and vaporized), it is returned to the compressor 11 via the accumulator 23 through the second refrigerant control unit 17.

However, when switching the operation mode between the heating operation and the dehumidifying heating operation, the first refrigerant control unit (on-off valve) is operated and closed during the heating operation and opened during the dehumidifying and heating operation to switch the operation mode. When the above is adopted, in the heating operation, the high-pressure refrigerant is not supplied to the second expansion device, so that the pressure in the path between the first refrigerant control unit and the second expansion device gradually decreases. After that, when the heating operation is switched to the dehumidifying heating operation (when the first refrigerant control unit is opened), the high-pressure refrigerant in the refrigerant path between the first heat exchanger 2 and the first expansion device 12 becomes the first. There is an inconvenience that it flows into the second expansion device 14 at once through the bypass flow path 16 of 1 and generates an abnormal noise.

Therefore, in the present invention, in the heating operation, the second expansion device 14 is closed and the first refrigerant control unit 15 is opened, and the first heat exchanger 2 and the first expansion are also performed in the heating operation. The high-pressure refrigerant between the device 12 and the device 12 is guided to the inlet of the second expansion device 14, so that the high-pressure refrigerant does not flow into the second expansion device 14 at once when the heating operation is switched to the dehumidifying heating operation. I try to suppress the generation of abnormal noise.

That is, instead of the conventional method in which the switching between the heating operation and the dehumidifying heating operation is supported by opening and closing the first refrigerant control unit 15, the first refrigerant control unit 15 is maintained in the open state (first). The operation mode is switched between the heating operation and the dehumidifying heating operation only by opening and closing the second expansion device 14 without operating the refrigerant control unit 15 of the above.

More specifically, as shown in FIG. 3, during the dehumidifying and heating operation (Parallel), the first and second refrigerant control units 15 and 17 are opened, and the first and second expansion devices 12 and 14 are opened. Is in the squeezed state. As a result, the refrigerant discharged from the compressor is radiated (condensed and liquefied) by the first heat exchanger 2 as described above, and then branched, and one of them passes through the first bypass flow path 16 and is second. It reaches the expansion device 14 of the above, where the pressure is reduced, heat is 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.
In FIG. 3, the path filled with the high-pressure refrigerant is shown by a thick solid line, and the path filled with the low-pressure refrigerant is shown by a thick broken line.

After that, when shifting to the heating operation, not only the second refrigerant control unit 17 but also the first refrigerant control unit 15 is maintained in an open state, and the second expansion device 14 is closed in that state. The damper 10 is set to a heating position (a position where the opening degree is 100%, a position where the damper is fully hot).
As a result, the compressed refrigerant discharged from the compressor 11 is dissipated (condensed and liquefied) by the first heat exchanger 2, and then even if it tries to flow into the first bypass passage, the flow is blocked by the second expansion device 14. Therefore, the pressure is reduced by the first expansion device 12 without flowing through the first bypass passage to reach the vehicle interior heat exchanger 4, where heat is absorbed (evaporated and vaporized) and then the second refrigerant control unit 17 is used. It is returned to the compressor 11 via the accumulator 23.

Further, when the operation shifts to the dehumidifying / heating operation again after that, since the first refrigerant control unit 15 is open, the high-pressure refrigerant (first heat exchanger) reaches the inflow port of the second expansion device 14. Even if it is filled with the refrigerant in the refrigerant path between the 2 and the first expansion device 12) and then the second expansion device 14 is opened, the high-pressure refrigerant flows into the second expansion device 14 at once. Since there is no such thing, it is possible to suppress the generation of sudden abnormal noise.

In this way, in the switching between the heating operation and the dehumidifying heating operation, the heating operation is performed by closing the second expansion device 14 while keeping the first refrigerant control unit 15 in the open state. Since the dehumidifying and heating operation is performed by setting the second expansion device 14 in the throttle state, the pressure acting on the second expansion device 14 does not suddenly change before and after the switching (before and after the first refrigerant control unit 15). (It is possible to prevent a pressure difference from occurring), and the high-pressure refrigerant does not suddenly flow into the second expansion device 14, and it is possible to avoid the generation of noise when switching the operation mode.
Further, in the above-mentioned switching, it is not necessary to bother to stop the compressor, so that it is possible to shorten the switching time of the operation mode.

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 (EVA 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 50 Control means 100 Refrigeration cycle

Claims (4)

A refrigeration cycle (100) and a control means (50) for switching and controlling the operation mode of the refrigeration cycle (100) are provided.
The refrigeration cycle (100)
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 on the upstream side in the air conditioning unit (1) with respect to the first heat exchanger (2), 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. death,
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.
Between the refrigerant flow path between the first heat exchanger (2) and the first expansion device (12) and between the vehicle interior heat exchanger (4) and the second expansion device (14). Is connected to the refrigerant flow path of the above 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 portion (13) that blocks the flow of the refrigerant from the merging portion (A) to the upstream side is provided, and the refrigerant flow between the vehicle interior heat exchanger (4) and the backflow blocking portion (13). A second bypass flow path (18) provided with a second refrigerant control unit (17) for the refrigerant flow path between the path, the second heat exchanger (3), and the compressor (11). Connect via
The control means (50) is
The refrigerant discharged from the compressor (11) is dissipated by the first heat exchanger (2), and the dissipated refrigerant is depressurized by the first expansion device (12), and then the outside heat of the passenger compartment is generated. A heating operation in which heat is absorbed by the exchanger (4) and then returned to the compressor (11) via the second bypass passage (18) without passing through the second heat exchanger (3). When,
The refrigerant discharged from the compressor (11) is radiated by the first heat exchanger (2), and the radiated refrigerant is branched, while passing through the first bypass passage (16). After depressurizing with the second inflator (14), heat is absorbed through the second heat exchanger (3), and on the other hand, after depressurizing with the first inflator (12), the outdoor heat exchanger is used. Dehumidifying and heating operation in which heat is absorbed in (4) and returned to the compressor (11) via the second bypass passage (18).
In the vehicle air conditioner that can be switched
The control means (50) switches from the dehumidifying heating operation to the heating operation by switching the second expansion device (14) from the throttled state to the closed state when switching between the heating operation and the dehumidifying heating operation. Vehicle air conditioning having a first switching means and a second switching means for switching from the heating operation to the dehumidifying heating operation by switching the second expansion device (14) from the closed state to the throttle state. Device. The vehicle air conditioner according to claim 1, wherein the control means (50) keeps the first refrigerant control unit (15) in an open state when switching between the heating operation and the dehumidifying heating operation. Device. 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 on the upstream side in the air conditioning unit (1) with respect to the first heat exchanger (2), 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. death,
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.
Between the refrigerant flow path between the first heat exchanger (2) and the first expansion device (12) and between the vehicle interior heat exchanger (4) and the second expansion device (14). Is connected to the refrigerant flow path of the above 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), upstream of the merging portion (A) with the first bypass flow path (16). A backflow blocking portion (13) that blocks the flow of the refrigerant from the merging portion (A) to the upstream side is provided, and the refrigerant flow between the vehicle interior heat exchanger (4) and the backflow blocking portion (13). A second bypass flow path (18) provided with a second refrigerant control unit (17) for the refrigerant flow path between the path, the second heat exchanger (3), and the compressor (11). In the operation mode switching control method of a vehicle air conditioner having a refrigeration cycle connected via
The refrigerant discharged from the compressor (11) is dissipated by the first heat exchanger (2), and the dissipated refrigerant is depressurized by the first expansion device (12), and then the outside heat of the passenger compartment is generated. A heating operation in which heat is absorbed by the exchanger (4) and then returned to the compressor (11) via the second bypass passage (18) without passing through the second heat exchanger (3). When,
The refrigerant discharged from the compressor (11) is radiated by the first heat exchanger (2), and the radiated refrigerant is branched, while passing through the first bypass passage (16). After depressurizing with the second inflator (14), heat is absorbed through the second heat exchanger (3), and on the other hand, after depressurizing with the first inflator (12), the outdoor heat exchanger is used. Dehumidifying and heating operation in which heat is absorbed in (4) and returned to the compressor (11) via the second bypass passage (18).
In switching
Switching from the dehumidifying heating operation to the heating operation by switching the second expansion device (14) from the throttle state to the closed state, and switching the second expansion device (14) from the closed state to the throttle state. A method for controlling operation mode switching of an air conditioner for a vehicle, which comprises switching from the heating operation to the dehumidifying heating operation. The operation mode switching control method for a vehicle air conditioner according to claim 3, wherein the first refrigerant control unit (15) is maintained in an open state when switching between the heating operation and the dehumidifying heating operation.

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