WO2017146266A1 - Air-conditioning device for vehicle - Google Patents

Abstract

Provided is an air-conditioning device for a vehicle comprising an opening/closing valve for switching flow paths and a bypass pipe that bypasses a radiator and an outside-passenger-compatment expansion valve, wherein the noise generated when opening the opening/closing valve while switching between cooling mode and maximum cooling mode, for example, is reduced or eliminated. The following modes are switched between and executed: a cooling mode in which a solenoid valve (30) is opened and a solenoid valve (40) is closed; and a MAX cooling mode in which the solenoid valve (30) is closed and the solenoid valve (40) is opened, and refrigerant is fed to an outside-passenger-compatment heat exchanger (7) via the bypass pipe (35). When switching from cooling mode to MAX cooling mode, a controller performs control to reduce noise, wherein after reducing the pressure differential before and after the solenoid valve (40), the solenoid valve (40) is opened and the solenoid valve (30) is closed, and the outside-passenger-compatment expansion valve (6) is completely closed.

Description

Air conditioner for vehicles

The present invention relates to a heat pump type air conditioner that air-conditions the interior of a vehicle, and more particularly to an air conditioner that can be applied to a hybrid vehicle or an electric vehicle.

Recently, hybrid vehicles and electric vehicles have become popular due to the emergence of environmental problems. As an air conditioner that can be applied to such a vehicle, a compressor that compresses and discharges the refrigerant, an internal condenser that is provided on the vehicle interior side and dissipates the refrigerant, and is provided on the vehicle interior side. An evaporator that absorbs the refrigerant, an external condenser that dissipates or absorbs heat from the passenger compartment, a first expansion valve that expands the refrigerant that flows into the external condenser, and a refrigerant that flows into the evaporator A second expansion valve for expanding the internal combustion engine, piping for bypassing the internal condenser and the first expansion valve, and flowing the refrigerant discharged from the compressor to the internal condenser or bypassing the internal condenser and the first expansion valve A first valve that switches between direct flow from the pipe to the external condenser, the refrigerant discharged from the compressor is caused to flow through the internal condenser by the first valve to dissipate the heat, and the discharged refrigerant is passed through the first expansion valve. After heating, the refrigerant discharged from the compressor is radiated in the internal condenser by the first valve, the radiated refrigerant is depressurized by the second expansion valve, and the refrigerant absorbs heat in the evaporator. The dehumidification mode to be performed, and the refrigerant discharged from the compressor bypasses the internal condenser and the first expansion valve by the first valve and flows to the external condenser to radiate heat, and after the pressure is reduced by the second expansion valve, A device that switches and executes a cooling mode for absorbing heat has been developed (see, for example, Patent Document 1).

JP2013-23210A JP 2014-88151 A

Here, when the first valve of Patent Document 1 is configured with two on-off valves provided in each refrigerant pipe branched from the discharge side of the compressor, when switching to the cooling mode, the other heating mode, and the dehumidifying mode, One of the on-off valves is opened and the other is closed. However, since the pressure difference before and after these on-off valves is large, there is a problem that a relatively large noise is generated by the refrigerant that flows suddenly to the on-off valves that are opened.
Here, when switching between heating and cooling, there has been proposed one that suppresses the generation of abnormal noise by lowering the pressure difference between the high pressure side and the low pressure side of the refrigerant circuit and then opening the on-off valve (for example, Patent Documents). 2).
The present invention has been made to solve the conventional technical problems, and is equipped with a bypass pipe that bypasses a radiator and an outdoor expansion valve, and an air conditioner for a vehicle that includes an on-off valve for switching a flow path. An object of the present invention is to eliminate or reduce noise generated when an on-off valve is opened when switching between a cooling mode and a maximum cooling mode.

An air conditioner for a vehicle according to a first aspect of the present invention includes a compressor that compresses a refrigerant, an air flow passage through which air supplied to the vehicle interior flows, and air that radiates the refrigerant and supplies the refrigerant to the vehicle interior from the air flow passage. A heat sink for heating the air, a heat absorber for absorbing the refrigerant to cool the air supplied from the air flow passage to the vehicle interior, an outdoor heat exchanger provided outside the vehicle interior, and the radiator An outdoor expansion valve for decompressing the refrigerant flowing into the outdoor heat exchanger, a first on-off valve provided between the discharge side of the compressor and the inlet side of the radiator, and upstream of the first on-off valve A bypass pipe for branching on the side, bypassing the radiator and the outdoor expansion valve to flow the refrigerant discharged from the compressor to the outdoor heat exchanger, a second on-off valve provided in the bypass pipe, and a control A first opening / closing valve and a second opening / closing by the control device. Cooling mode in which the refrigerant discharged from the compressor flows from the radiator to the outdoor heat exchanger and is radiated by the outdoor heat exchanger, and the radiated refrigerant is decompressed and then absorbed by the heat absorber. The outdoor expansion valve is fully closed, the first on-off valve is closed, and the second on-off valve is opened, so that the refrigerant discharged from the compressor flows to the outdoor heat exchanger through the bypass pipe to dissipate heat. After the pressure of the refrigerant is reduced, the maximum cooling mode in which heat is absorbed by the heat absorber is switched and executed. The control device switches the pressure difference before and after the second on-off valve when switching from the cooling mode to the maximum cooling mode. Is reduced, the second on-off valve is opened, the first on-off valve is closed, and the outdoor expansion valve is fully closed, and noise improvement control is executed.
According to a second aspect of the present invention, in the vehicle air conditioner according to the second aspect of the present invention, the control device controls the rotation speed of the compressor or stops the compressor before and after the second on-off valve in the noise improvement control. When the pressure difference is reduced to a predetermined value or less, the second on-off valve is opened, the first on-off valve is closed, and the outdoor expansion valve is fully closed. .
According to a third aspect of the present invention, there is provided a vehicular air conditioner according to the first aspect of the present invention, wherein the control device stops the compressor and opens the second on-off valve after a predetermined period of time in the noise improvement control. The valve is closed and the outdoor expansion valve is fully closed.
According to a fourth aspect of the present invention, there is provided an air conditioning apparatus for a vehicle, comprising: a compressor that compresses a refrigerant; an air flow passage through which air supplied to a vehicle interior flows; A heat sink for heating the air, a heat absorber for absorbing the refrigerant to cool the air supplied from the air flow passage to the vehicle interior, an outdoor heat exchanger provided outside the vehicle interior, and the radiator An outdoor expansion valve for decompressing the refrigerant flowing into the outdoor heat exchanger, a first on-off valve provided between the discharge side of the compressor and the inlet side of the radiator, and upstream of the first on-off valve A bypass pipe for branching on the side, bypassing the radiator and the outdoor expansion valve to flow the refrigerant discharged from the compressor to the outdoor heat exchanger, a second on-off valve provided in the bypass pipe, and a control A first opening / closing valve and a second opening / closing by the control device. Cooling mode in which the refrigerant discharged from the compressor flows from the radiator to the outdoor heat exchanger and is radiated by the outdoor heat exchanger, and the radiated refrigerant is decompressed and then absorbed by the heat absorber. The outdoor expansion valve is fully closed, the first on-off valve is closed, and the second on-off valve is opened, so that the refrigerant discharged from the compressor flows to the outdoor heat exchanger through the bypass pipe to dissipate heat. After the decompression of the refrigerant, the maximum cooling mode in which heat is absorbed by the heat absorber is switched and executed. The control device switches the pressure difference before and after the first on-off valve when switching from the maximum cooling mode to the cooling mode. After the reduction, the first on-off valve is opened, and the noise improvement control for closing the second on-off valve is executed.
According to a fifth aspect of the present invention, in the vehicle air conditioner according to the fifth aspect of the invention, in the noise improvement control, the control device reduces the pressure difference before and after the first on-off valve by opening the outdoor expansion valve, and the pressure difference is predetermined. When the value is less than or equal to the value, the first on-off valve is opened and the second on-off valve is closed.
According to a sixth aspect of the present invention, there is provided an air conditioning apparatus for a vehicle according to the present invention, wherein the control device controls the rotational speed of the compressor in the noise improvement control or stops the compressor before and after the first on-off valve. When the pressure difference before and after the first on-off valve is higher than the predetermined value at the time when the outdoor expansion valve is fully opened, the first rotational speed is controlled by controlling the rotational speed of the compressor. The pressure difference before and after the on-off valve is reduced.
An air conditioner for a vehicle according to a seventh aspect of the invention includes a compressor that compresses a refrigerant, an air flow passage through which air supplied to the vehicle interior flows, and air that radiates the refrigerant and supplies the refrigerant to the vehicle interior from the air flow passage A heat sink for heating the air, a heat absorber for absorbing the refrigerant to cool the air supplied from the air flow passage to the vehicle interior, an outdoor heat exchanger provided outside the vehicle interior, and the radiator An outdoor expansion valve for decompressing the refrigerant flowing into the outdoor heat exchanger, a first on-off valve provided between the discharge side of the compressor and the inlet side of the radiator, and upstream of the first on-off valve A bypass pipe for branching on the side, bypassing the radiator and the outdoor expansion valve to flow the refrigerant discharged from the compressor to the outdoor heat exchanger, a second on-off valve provided in the bypass pipe, and a control And at least the outdoor expansion valve is fully closed by this control device. By closing the first on-off valve and opening the second on-off valve, the refrigerant discharged from the compressor is caused to flow through the outdoor heat exchanger through the bypass pipe to dissipate the heat, and after the decompressed refrigerant is decompressed, the heat absorber And the first on-off valve is an electromagnetic valve that closes in an energized state and opens in a non-energized state, and the control device stops operation from the maximum cooling mode. Then, after reducing the pressure difference before and after the first on-off valve, noise improvement control is performed to de-energize the first on-off valve.
According to an eighth aspect of the present invention, in the vehicle air conditioner according to the present invention, the control device reduces the pressure difference before and after the first on-off valve by stopping the compressor and opening the outdoor expansion valve in the noise improvement control. The first on-off valve is de-energized when the pressure difference becomes a predetermined value or less.
According to a ninth aspect of the present invention, there is provided a vehicular air conditioner according to the seventh aspect of the present invention, wherein the control device stops the compressor and fully opens the outdoor expansion valve in the noise improvement control, and the outdoor expansion valve is fully opened. When the pressure difference before and after the first on-off valve is less than or equal to a predetermined value at the time, the first on-off valve is de-energized, and when the pressure difference is higher than the predetermined value, the pressure drops below the predetermined value, or The first on-off valve is deenergized after a predetermined time has elapsed.

According to the first aspect of the present invention, the compressor for compressing the refrigerant, the air flow passage through which the air supplied to the vehicle interior flows, and the air supplied to the vehicle interior from the air flow passage by radiating the refrigerant are heated. Radiator, a heat absorber for absorbing the refrigerant to cool the air supplied from the air flow passage to the vehicle interior, an outdoor heat exchanger provided outside the vehicle compartment, and an outdoor heat exchanger exiting the radiator An outdoor expansion valve for depressurizing the refrigerant flowing into the compressor, a first on-off valve provided between the discharge side of the compressor and the inlet side of the radiator, and a branch on the upstream side of the first on-off valve. A bypass pipe for bypassing the radiator and the outdoor expansion valve and allowing the refrigerant discharged from the compressor to flow to the outdoor heat exchanger, a second on-off valve provided in the bypass pipe, and a control device, With this control device, the first on-off valve is opened and the second on-off valve is closed. A cooling mode in which the refrigerant discharged from the compressor flows from the radiator to the outdoor heat exchanger, dissipates heat in the outdoor heat exchanger, and after the decompressed refrigerant is depressurized, heat is absorbed in the heat absorber, and outdoor expansion The valve is fully closed, the first on-off valve is closed, and the second on-off valve is opened, so that the refrigerant discharged from the compressor flows to the outdoor heat exchanger through the bypass pipe to dissipate the heat, In a vehicle air conditioner that switches and executes the maximum cooling mode in which heat is absorbed by the heat absorber after reducing the pressure, when the control device switches from the cooling mode to the maximum cooling mode, the pressure difference before and after the second on-off valve is reduced. After that, since the noise improvement control is executed to open the second on-off valve, close the first on-off valve, and fully close the outdoor expansion valve, when switching from the cooling mode to the maximum cooling mode, Open the 2 open / close valve When the bypass pipe can refrigerant toward the outdoor heat exchanger side is greatly suppressed or eliminated in that rapidly flows. Thereby, at the time of switching from the cooling mode to the maximum cooling mode, noise generated when the second on-off valve is opened can be eliminated or reduced.
In this case, the control device as in the second aspect of the invention reduces the pressure difference before and after the second on-off valve by controlling the rotational speed of the compressor or stopping the compressor in the noise improvement control. When the pressure difference becomes a predetermined value or less, the second on-off valve is opened, the first on-off valve is closed, and the outdoor expansion valve is fully closed. In the control, the pressure difference before and after the second on-off valve is effectively reduced by lowering the pressure on the refrigerant upstream side of the second on-off valve, the maximum cooling mode is quickly switched, and the noise generated at the time of switching is reduced. It can be solved or reduced accurately.
In the noise improvement control, the control device stops the compressor, opens the second on-off valve after a predetermined time, closes the first on-off valve, and fully closes the outdoor expansion valve. Even in this case, in the noise improvement control at the time of mode switching, the pressure upstream and downstream of the second on-off valve is effectively reduced by reducing the pressure on the upstream side of the refrigerant of the second on-off valve. Noise can be eliminated or reduced accurately. Further, before switching from the cooling mode to the maximum cooling mode as in the inventions of the second and third aspects, that is, before the first on-off valve is closed and the outdoor expansion valve is fully closed, the rotation of the compressor is started. Since the number is controlled or stopped, it is possible to reduce the amount of refrigerant that lies in the radiator when the maximum cooling mode is switched. Thereby, the refrigerant circulation amount during execution of the maximum cooling mode can be ensured, and the decrease in capacity can be suppressed or prevented.
According to the invention of claim 4, the compressor for compressing the refrigerant, the air flow passage through which the air supplied to the vehicle interior flows, and the air supplied to the vehicle interior from the air flow passage by radiating the refrigerant are heated. Radiator, a heat absorber for absorbing the refrigerant to cool the air supplied from the air flow passage to the vehicle interior, an outdoor heat exchanger provided outside the vehicle compartment, and an outdoor heat exchanger exiting the radiator An outdoor expansion valve for depressurizing the refrigerant flowing into the compressor, a first on-off valve provided between the discharge side of the compressor and the inlet side of the radiator, and a branch on the upstream side of the first on-off valve. A bypass pipe for bypassing the radiator and the outdoor expansion valve and allowing the refrigerant discharged from the compressor to flow to the outdoor heat exchanger, a second on-off valve provided in the bypass pipe, and a control device, With this control device, the first on-off valve is opened and the second on-off valve is closed. A cooling mode in which the refrigerant discharged from the compressor flows from the radiator to the outdoor heat exchanger, dissipates heat in the outdoor heat exchanger, and after the decompressed refrigerant is depressurized, heat is absorbed in the heat absorber, and outdoor expansion The valve is fully closed, the first on-off valve is closed, and the second on-off valve is opened, so that the refrigerant discharged from the compressor flows to the outdoor heat exchanger through the bypass pipe to dissipate the heat, In a vehicle air conditioner that switches and executes the maximum cooling mode in which heat is absorbed by the heat absorber after depressurization, when the control device switches from the maximum cooling mode to the cooling mode, the pressure difference before and after the first on-off valve is reduced. After that, since the noise improvement control is executed to open the first on-off valve and close the second on-off valve, when switching from the maximum cooling mode to the cooling mode, the first on-off valve is opened. , Radiator side Toward the refrigerant can be significantly suppressed or eliminated that rapidly flows. Thereby, at the time of switching from the maximum cooling mode to the cooling mode, noise generated when the first on-off valve is opened can be eliminated or reduced.
In this case, when the control device reduces the pressure difference before and after the first on-off valve by opening the outdoor expansion valve in the noise improvement control as in the fifth aspect of the invention, and the pressure difference becomes a predetermined value or less. In addition, if the first on-off valve is opened and the second on-off valve is closed, in the noise improvement control at the time of mode switching, the first on-off valve is increased by increasing the pressure downstream of the refrigerant. The pressure difference between the front and rear valves can be effectively reduced to quickly switch to the cooling mode, and noise generated at the time of switching can be accurately eliminated or reduced.
Further, in addition to the above invention, the control device may control the rotation speed of the compressor in the noise improvement control, or reduce the pressure difference before and after the first on-off valve by stopping the compressor, or When the pressure difference before and after the first opening / closing valve is higher than the predetermined value when the outdoor expansion valve is fully opened, the pressure difference before and after the first opening / closing valve is reduced by controlling the rotation speed of the compressor. In this way, the pressure difference before and after the first on-off valve can be reduced more quickly and effectively.
According to the seventh aspect of the present invention, the compressor for compressing the refrigerant, the air flow passage through which the air supplied to the vehicle interior flows, and the air supplied to the vehicle interior from the air flow passage by dissipating the refrigerant are heated. Radiator, a heat absorber for absorbing the refrigerant to cool the air supplied from the air flow passage to the vehicle interior, an outdoor heat exchanger provided outside the vehicle compartment, and an outdoor heat exchanger exiting the radiator An outdoor expansion valve for depressurizing the refrigerant flowing into the compressor, a first on-off valve provided between the discharge side of the compressor and the inlet side of the radiator, and a branch on the upstream side of the first on-off valve. A bypass pipe for bypassing the radiator and the outdoor expansion valve and allowing the refrigerant discharged from the compressor to flow to the outdoor heat exchanger, a second on-off valve provided in the bypass pipe, and a control device, By this control device, at least the outdoor expansion valve is fully closed, and the first on-off valve The maximum cooling that closes and opens the second on-off valve causes the refrigerant discharged from the compressor to flow through the outdoor heat exchanger through the bypass pipe to dissipate the heat, decompress the refrigerant that has been radiated, and then absorb the heat with the heat absorber In the vehicle air conditioner that executes the mode, when the first on-off valve is an electromagnetic valve that closes in an energized state and opens in a non-energized state, when the control device stops operation from the maximum cooling mode, Since the noise improvement control for de-energizing the first on-off valve is executed after reducing the pressure difference before and after the on-off valve, when the operation is stopped from the maximum cooling mode, the first on-off valve is When the first on-off valve is opened as non-energized, it is possible to greatly suppress or eliminate the sudden flow of the refrigerant toward the radiator side. As a result, when the operation is stopped from the maximum cooling mode, noise generated by opening the first on-off valve can be eliminated or reduced.
In this case, in the noise improvement control, the control device stops the compressor and opens the outdoor expansion valve to reduce the pressure difference before and after the first on-off valve. If the first on-off valve is de-energized when the value becomes less than the value, the pressure difference before and after the first on-off valve is effective in the noise improvement control when the operation is stopped from the maximum cooling mode. Therefore, the first on-off valve can be quickly de-energized, and the noise generated at the time of stopping can be accurately eliminated or reduced.
According to the ninth aspect of the present invention, in the noise improvement control, the control device stops the compressor, fully opens the outdoor expansion valve, and before and after the first on-off valve when the outdoor expansion valve is fully opened. When the pressure difference is less than or equal to a predetermined value, the first on-off valve is de-energized. When the pressure difference is higher than the predetermined value, the first on-off valve is Even in the case of non-energization, in the noise improvement control when the operation is stopped from the maximum cooling mode, the pressure difference before and after the first on-off valve is effectively reduced, and the first on-off valve is quickly de-energized. In addition, noise generated at the time of stopping can be eliminated or reduced accurately.

It is a block diagram of the air conditioning apparatus for vehicles of one Embodiment to which this invention is applied (heating mode, dehumidification heating mode, dehumidification cooling mode, and cooling mode). It is a block diagram of the electric circuit of the controller of the vehicle air conditioner of FIG. It is a block diagram at the time of the MAX cooling mode (maximum cooling mode) of the vehicle air conditioner of FIG. 3 is a timing chart of each device for explaining an example of noise improvement control executed by the controller of FIG. 2 when switching from the cooling mode to the MAX cooling mode (maximum cooling mode). It is a timing chart of each apparatus explaining an example of the noise improvement control which the controller of FIG. 2 performs when switching from the MAX cooling mode (maximum cooling mode) to the cooling mode. It is a timing chart of each apparatus explaining an example of the noise improvement control which the controller of FIG. 2 performs when a driving | operation is stopped from MAX cooling mode (maximum cooling mode).

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a configuration diagram of a vehicle air conditioner 1 according to an embodiment of the present invention. A vehicle according to an embodiment to which the present invention is applied is an electric vehicle (EV) in which an engine (internal combustion engine) is not mounted, and travels by driving an electric motor for traveling with electric power charged in a battery. Yes (both not shown), the vehicle air conditioner 1 of the present invention is also driven by the power of the battery. That is, the vehicle air conditioner 1 of the embodiment performs a heating mode by a heat pump operation using a refrigerant circuit in an electric vehicle that cannot be heated by engine waste heat, and further includes a dehumidifying heating mode, a dehumidifying cooling mode, a cooling mode, Each operation mode of the MAX cooling mode (maximum cooling mode) is selectively executed.
The present invention is effective not only for electric vehicles but also for so-called hybrid vehicles that use an engine and an electric motor for traveling, and is also applicable to ordinary vehicles that run on an engine. Needless to say.
The vehicle air conditioner 1 according to the embodiment performs air conditioning (heating, cooling, dehumidification, and ventilation) in a vehicle interior of an electric vehicle, and includes an electric compressor 2 that compresses refrigerant and vehicle interior air. Is provided in the air flow passage 3 of the HVAC unit 10 through which air is circulated, and the high-temperature and high-pressure refrigerant discharged from the compressor 2 flows in through the refrigerant pipe 13G, and dissipates the refrigerant into the vehicle compartment. And an outdoor expansion valve 6 comprising an electric valve that decompresses and expands the refrigerant during heating, and functions as a radiator during cooling and functions as a radiator during heating, and exchanges heat between the refrigerant and the outside air so as to function as an evaporator during heating. An outdoor heat exchanger 7 that performs the above operation, an indoor expansion valve 8 that is an electric valve that decompresses and expands the refrigerant, and a heat absorber 9 that is provided in the air flow passage 3 and absorbs heat from outside the vehicle interior to the refrigerant during cooling and dehumidification. And accumulator 12 etc. Are sequentially connected by a refrigerant pipe 13, the refrigerant circuit R is formed.
The refrigerant circuit R is filled with a predetermined amount of refrigerant and lubricating oil. The outdoor heat exchanger 7 is provided with an outdoor blower 15. The outdoor blower 15 exchanges heat between the outside air and the refrigerant by forcibly passing outside air through the outdoor heat exchanger 7, so that the outdoor air blower 15 can also be used outdoors even when the vehicle is stopped (that is, the vehicle speed is 0 km / h). It is comprised so that external air may be ventilated by the heat exchanger 7. FIG.
The outdoor heat exchanger 7 has a receiver dryer section 14 and a supercooling section 16 sequentially on the downstream side of the refrigerant, and the refrigerant pipe 13A exiting from the outdoor heat exchanger 7 is received via an electromagnetic valve 17 opened during cooling. The refrigerant pipe 13 </ b> B connected to the dryer unit 14 and on the outlet side of the supercooling unit 16 is connected to the inlet side of the heat absorber 9 via the indoor expansion valve 8. In addition, the receiver dryer part 14 and the supercooling part 16 structurally constitute a part of the outdoor heat exchanger 7.
The refrigerant pipe 13B between the subcooling section 16 and the indoor expansion valve 8 is provided in a heat exchange relationship with the refrigerant pipe 13C on the outlet side of the heat absorber 9, and constitutes an internal heat exchanger 19 together. Thus, the refrigerant flowing into the indoor expansion valve 8 through the refrigerant pipe 13B is cooled (supercooled) by the low-temperature refrigerant that has exited the heat absorber 9.
Further, the refrigerant pipe 13A exiting from the outdoor heat exchanger 7 is branched into a refrigerant pipe 13D, and this branched refrigerant pipe 13D is downstream of the internal heat exchanger 19 via an electromagnetic valve 21 opened during heating. The refrigerant pipe 13C is connected in communication. The refrigerant pipe 13 </ b> C is connected to the accumulator 12, and the accumulator 12 is connected to the refrigerant suction side of the compressor 2. Further, the refrigerant pipe 13E on the outlet side of the radiator 4 is connected to the inlet side of the outdoor heat exchanger 7 via the outdoor expansion valve 6.
A refrigerant pipe 13G between the discharge side of the compressor 2 and the inlet side of the radiator 4 is provided with a solenoid valve 30 (which constitutes a flow path switching device) that is closed during dehumidification heating and MAX cooling described later. Yes. In this case, the refrigerant pipe 13G is branched into a bypass pipe 35 on the upstream side of the electromagnetic valve 30, and the bypass pipe 35 is opened by the electromagnetic valve 40 (which also constitutes a flow path switching device) during dehumidifying heating and MAX cooling. ) Through the refrigerant pipe 13E on the downstream side of the outdoor expansion valve 6. These bypass pipe 35, electromagnetic valve 30 and electromagnetic valve 40 constitute a bypass device 45 in the present invention.
Since the bypass device 45 is configured by the bypass pipe 35, the electromagnetic valve 30, and the electromagnetic valve 40, the dehumidifying heating mode or the MAX for allowing the refrigerant discharged from the compressor 2 to directly flow into the outdoor heat exchanger 7 as will be described later. Switching between the cooling mode and the heating mode in which the refrigerant discharged from the compressor 2 flows into the radiator 4, the dehumidifying cooling mode, and the cooling mode can be performed smoothly.
The air flow passage 3 on the air upstream side of the heat absorber 9 is formed with each of an outside air inlet and an inside air inlet (represented by the inlet 25 in FIG. 1). 25 is provided with a suction switching damper 26 for switching the air introduced into the air flow passage 3 between the inside air (inside air circulation mode) which is air inside the passenger compartment and the outside air (outside air introduction mode) which is outside the passenger compartment. Yes. Furthermore, an indoor blower (blower fan) 27 for supplying the introduced inside air or outside air to the air flow passage 3 is provided on the air downstream side of the suction switching damper 26.
Moreover, in FIG. 1, 23 is an auxiliary heater as an auxiliary heating device provided in the vehicle air conditioner 1 of the embodiment. The auxiliary heater 23 of the embodiment is composed of a PTC heater which is an electric heater, and is provided in the air flow passage 3 on the air upstream side of the radiator 4 with respect to the air flow in the air flow passage 3. Yes. When the auxiliary heater 23 is energized and generates heat, the air in the air flow passage 3 flowing into the radiator 4 through the heat absorber 9 is heated. In other words, the auxiliary heater 23 serves as a so-called heater core, which heats or complements the passenger compartment.
In addition, air in the air flow passage 3 on the upstream side of the auxiliary heater 23 flows into the air flow passage 3 and assists air (inside air or outside air) in the air flow passage 3 after passing through the heat absorber 9. An air mix damper 28 is provided for adjusting the ratio of ventilation through the heater 23 and the radiator 4. Further, FOOT (foot), VENT (vent), and DEF (def) outlets (represented by the outlet 29 as a representative in FIG. 1) are formed in the air flow passage 3 on the air downstream side of the radiator 4. The air outlet 29 is provided with an air outlet switching damper 31 that performs switching control of air blowing from the air outlets.
Next, in FIG. 2, reference numeral 32 denotes a controller (ECU) as a control device composed of a microcomputer which is an example of a computer provided with a processor. The controller 32 detects the outside air temperature (Tam) of the vehicle. The outside air temperature sensor 33 for detecting the outside air humidity, the HVAC suction temperature sensor 36 for detecting the temperature of the air sucked into the air flow passage 3 from the suction port 25, and the air (inside air) in the passenger compartment. An inside air temperature sensor 37 that detects the temperature, an inside air humidity sensor 38 that detects the humidity of the air in the vehicle interior, an indoor CO ₂ concentration sensor 39 that detects the carbon dioxide concentration in the vehicle interior, and an air outlet from the air outlet 29 And a discharge pressure sensor 41 for detecting the discharge refrigerant pressure (discharge pressure Pd) of the compressor 2. , A discharge temperature sensor 43 that detects the discharge refrigerant temperature of the compressor 2, a suction pressure sensor 44 that detects the suction refrigerant pressure of the compressor 2, and a suction temperature sensor 55 that detects the suction refrigerant temperature of the compressor 2. And a radiator temperature sensor 46 that detects the temperature of the radiator 4 (the temperature of the air that has passed through the radiator 4 or the temperature of the radiator 4 itself: the radiator temperature TH), and the refrigerant pressure (the radiator of the radiator 4). 4 or a radiator pressure sensor 47 that detects the pressure of the refrigerant immediately after exiting the radiator 4: the radiator pressure PCI, and the temperature of the heat absorber 9 (the temperature of the air passing through the heat absorber 9 or the heat absorption). The temperature of the heat exchanger 9 itself: a heat absorber temperature sensor 48 that detects the heat absorber temperature Te) and the refrigerant pressure of the heat absorber 9 (the pressure of the refrigerant in the heat absorber 9 or immediately after leaving the heat absorber 9). A heat absorber pressure sensor 49 for detecting the amount of solar radiation into the passenger compartment For example, a photosensor-type solar radiation sensor 51, a vehicle speed sensor 52 for detecting the moving speed (vehicle speed) of the vehicle, an air conditioning (air conditioner) operation unit 53 for setting a set temperature and an operation mode, and outdoor heat An outdoor heat exchanger temperature sensor 54 for detecting the temperature of the exchanger 7 (the temperature of the refrigerant immediately after leaving the outdoor heat exchanger 7 or the temperature of the outdoor heat exchanger 7 itself: the outdoor heat exchanger temperature TXO); The pressure of the outdoor heat exchanger pressure sensor 56 that detects the refrigerant pressure of the outdoor heat exchanger 7 (the pressure of the refrigerant in the outdoor heat exchanger 7 or immediately after exiting the outdoor heat exchanger 7: outdoor heat exchanger pressure PXO). Each output is connected. Further, the input of the controller 32 further includes an auxiliary heater temperature sensor for detecting the temperature of the auxiliary heater 23 (the temperature of the air immediately after being heated by the auxiliary heater 23 or the temperature of the auxiliary heater 23 itself: the auxiliary heater temperature Tptc). 50 outputs are also connected.
On the other hand, the output of the controller 32 includes the compressor 2, the outdoor blower 15, the indoor blower (blower fan) 27, the suction switching damper 26, the air mix damper 28, the outlet switching damper 31, and the outdoor expansion. Solenoid valve 6, indoor expansion valve 8, auxiliary heater 23, solenoid valve 30 (for dehumidification), solenoid valve 17 (for cooling), solenoid valve 21 (for heating), solenoid valve 40 (also for dehumidification) Is connected. And the controller 32 controls these based on the output of each sensor, and the setting input in the air-conditioning operation part 53. FIG.
Next, the operation of the vehicle air conditioner 1 having the above-described configuration will be described. In the embodiment, the controller 32 switches between the operation modes of the heating mode, the dehumidifying heating mode, the dehumidifying cooling mode, the cooling mode, and the MAX cooling mode (maximum cooling mode). First, an outline of refrigerant flow and control in each operation mode will be described.
(1) Heating mode When the heating mode is selected by the controller 32 (auto mode) or by the manual operation (manual mode) to the air conditioning operation unit 53, the controller 32 opens the solenoid valve 21 (for heating) and opens the solenoid valve. Close 17 (for cooling). Further, the electromagnetic valve 30 (for dehumidification) is opened, and the electromagnetic valve 40 (for dehumidification) is closed.
Then, the compressor 2 and each of the blowers 15 and 27 are operated, and the air mix damper 28 is blown out from the indoor blower 27 and passes through the heat absorber 9 as shown by a broken line in FIG. It is assumed that air is passed through the auxiliary heater 23 and the radiator 4. As a result, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the radiator 4 from the refrigerant pipe 13G via the electromagnetic valve 30. Since the air in the airflow passage 3 is passed through the radiator 4, the air in the airflow passage 3 is converted into the high-temperature refrigerant in the radiator 4 (when the auxiliary heater 23 operates, the auxiliary heater 23 and the radiator 4. On the other hand, the refrigerant in the radiator 4 is cooled by being deprived of heat by the air, and is condensed and liquefied.
The refrigerant liquefied in the radiator 4 exits the radiator 4 and then reaches the outdoor expansion valve 6 through the refrigerant pipe 13E. The refrigerant flowing into the outdoor expansion valve 6 is decompressed there and then flows into the outdoor heat exchanger 7. The refrigerant flowing into the outdoor heat exchanger 7 evaporates, and pumps up heat from the outside air that is ventilated by traveling or by the outdoor blower 15. That is, the refrigerant circuit R becomes a heat pump. Then, the low-temperature refrigerant exiting the outdoor heat exchanger 7 enters the accumulator 12 from the refrigerant pipe 13C through the refrigerant pipe 13A, the electromagnetic valve 21 and the refrigerant pipe 13D, and is separated into gas and liquid there. Repeated circulation inhaled. Since the air heated by the radiator 4 (when the auxiliary heater 23 is operated, the auxiliary heater 23 and the radiator 4) is blown out from the outlet 29, the vehicle interior is thereby heated.
The controller 32 calculates a target radiator pressure PCO (target value of the radiator pressure PCI) from a target radiator temperature TCO (target value of the radiator temperature TH) calculated from a target outlet temperature TAO described later, and this target heat dissipation. The number of revolutions of the compressor 2 is controlled based on the compressor pressure PCO and the refrigerant pressure of the radiator 4 detected by the radiator pressure sensor 47 (radiator pressure PCI; high pressure of the refrigerant circuit R). Further, the controller 32 determines the valve opening degree of the outdoor expansion valve 6 based on the temperature of the radiator 4 (the radiator temperature TH) detected by the radiator temperature sensor 46 and the radiator pressure PCI detected by the radiator pressure sensor 47. And the supercooling degree SC of the refrigerant at the outlet of the radiator 4 is controlled. The target radiator temperature TCO is basically set to TCO = TAO, but a predetermined restriction on control is provided.
Further, in this heating mode, when the heating capacity by the radiator 4 is insufficient with respect to the heating capacity required for the vehicle interior air conditioning, the controller 32 assists so that the shortage is supplemented by the heat generated by the auxiliary heater 23. The energization of the heater 23 is controlled. Thereby, comfortable vehicle interior heating is realized and frost formation of the outdoor heat exchanger 7 is also suppressed. At this time, since the auxiliary heater 23 is disposed on the air upstream side of the radiator 4, the air flowing through the air flow passage 3 is vented to the auxiliary heater 23 before the radiator 4.
Here, when the auxiliary heater 23 is disposed on the air downstream side of the radiator 4, when the auxiliary heater 23 is configured by a PCT heater as in the embodiment, the temperature of the air flowing into the auxiliary heater 23 is determined by the radiator. 4, the resistance value of the PTC heater increases, the current value also decreases, and the heat generation amount decreases. However, by arranging the auxiliary heater 23 on the air upstream side of the radiator 4, Thus, the capacity of the auxiliary heater 23 composed of the PTC heater can be sufficiently exhibited.
(2) Dehumidification heating mode Next, in the dehumidification heating mode, the controller 32 opens the electromagnetic valve 17 and closes the electromagnetic valve 21. Further, the electromagnetic valve 30 is closed, the electromagnetic valve 40 is opened, and the valve opening degree of the outdoor expansion valve 6 is fully closed. Then, the compressor 2 and each of the blowers 15 and 27 are operated, and the air mix damper 28 is blown out from the indoor blower 27 and passes through the heat absorber 9 as shown by a broken line in FIG. It is assumed that air is passed through the auxiliary heater 23 and the radiator 4.
Accordingly, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 to the refrigerant pipe 13G flows into the bypass pipe 35 without going to the radiator 4, passes through the electromagnetic valve 40, and is connected to the refrigerant pipe on the downstream side of the outdoor expansion valve 6. 13E. At this time, since the outdoor expansion valve 6 is fully closed, the refrigerant flows into the outdoor heat exchanger 7. The refrigerant flowing into the outdoor heat exchanger 7 is cooled and condensed by running there or by the outside air ventilated by the outdoor blower 15. The refrigerant that has exited the outdoor heat exchanger 7 sequentially flows from the refrigerant pipe 13 </ b> A through the electromagnetic valve 17 into the receiver dryer unit 14 and the supercooling unit 16. Here, the refrigerant is supercooled.
The refrigerant that has exited the supercooling section 16 of the outdoor heat exchanger 7 enters the refrigerant pipe 13 </ b> B, reaches the indoor expansion valve 8 through the internal heat exchanger 19. After the refrigerant is depressurized by the indoor expansion valve 8, it flows into the heat absorber 9 and evaporates. The air blown out from the indoor blower 27 by the heat absorption action at this time is cooled, and moisture in the air condenses and adheres to the heat absorber 9, so that the air in the air flow passage 3 is cooled, and Dehumidified. The refrigerant evaporated in the heat absorber 9 reaches the accumulator 12 through the refrigerant pipe 13C through the internal heat exchanger 19, and repeats circulation that is sucked into the compressor 2 there through.
At this time, since the valve opening degree of the outdoor expansion valve 6 is fully closed, it is possible to suppress or prevent inconvenience that the refrigerant discharged from the compressor 2 flows backward from the outdoor expansion valve 6 into the radiator 4. It becomes. Thereby, the fall of a refrigerant | coolant circulation amount can be suppressed or eliminated and air-conditioning capability can be ensured now. Further, in this dehumidifying and heating mode, the controller 32 energizes the auxiliary heater 23 to generate heat. As a result, the air cooled and dehumidified by the heat absorber 9 is further heated in the process of passing through the auxiliary heater 23 and the temperature rises, so that the dehumidifying heating in the passenger compartment is performed.
The controller 32 controls the rotational speed of the compressor 2 on the basis of the temperature of the heat absorber 9 (heat absorber temperature Te) detected by the heat absorber temperature sensor 48 and the target heat absorber temperature TEO that is the target value, and the auxiliary heater temperature. By controlling the energization (heat generation) of the auxiliary heater 23 based on the auxiliary heater temperature Tptc detected by the sensor 50 and the target radiator temperature TCO described above, while appropriately cooling and dehumidifying the air in the heat absorber 9, A decrease in the temperature of the air blown from the outlet 29 into the passenger compartment by heating by the auxiliary heater 23 is accurately prevented.
As a result, it is possible to control the temperature to an appropriate heating temperature while dehumidifying the air blown into the vehicle interior, and it is possible to realize comfortable and efficient dehumidification heating in the vehicle interior. Further, as described above, in the dehumidifying heating mode, the air mix damper 28 is in a state where all the air in the air flow passage 3 is passed through the auxiliary heater 23 and the radiator 4, so that the air passing through the heat absorber 9 is efficiently assisted. Heating by the heater 23 can improve the energy saving performance, and the controllability of the dehumidifying heating air conditioning can also be improved.
In addition, since the auxiliary heater 23 is disposed on the air upstream side of the radiator 4, the air heated by the auxiliary heater 23 passes through the radiator 4. In this dehumidifying heating mode, the refrigerant is supplied to the radiator 4. Therefore, the disadvantage that the radiator 4 absorbs heat from the air heated by the auxiliary heater 23 is also eliminated. That is, the temperature of the air blown out into the vehicle compartment by the radiator 4 is suppressed, and the COP is improved.
(3) Dehumidifying and Cooling Mode Next, in the dehumidifying and cooling mode, the controller 32 opens the electromagnetic valve 17 and closes the electromagnetic valve 21. Further, the electromagnetic valve 30 is opened and the electromagnetic valve 40 is closed. Then, the compressor 2 and each of the blowers 15 and 27 are operated, and the air mix damper 28 is blown out from the indoor blower 27 and passes through the heat absorber 9 as shown by a broken line in FIG. It is assumed that air is passed through the auxiliary heater 23 and the radiator 4. As a result, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the radiator 4 from the refrigerant pipe 13G via the electromagnetic valve 30. Since the air in the air flow passage 3 is passed through the radiator 4, the air in the air flow passage 3 is heated by the high-temperature refrigerant in the radiator 4, while the refrigerant in the radiator 4 heats the air. It is deprived and cooled, and condensates.
The refrigerant that has exited the radiator 4 reaches the outdoor expansion valve 6 through the refrigerant pipe 13E, and flows into the outdoor heat exchanger 7 through the outdoor expansion valve 6 that is controlled to open. The refrigerant flowing into the outdoor heat exchanger 7 is cooled and condensed by running there or by the outside air ventilated by the outdoor blower 15. The refrigerant that has exited the outdoor heat exchanger 7 sequentially flows from the refrigerant pipe 13 </ b> A through the electromagnetic valve 17 into the receiver dryer unit 14 and the supercooling unit 16. Here, the refrigerant is supercooled.
The refrigerant that has exited the supercooling section 16 of the outdoor heat exchanger 7 enters the refrigerant pipe 13 </ b> B, reaches the indoor expansion valve 8 through the internal heat exchanger 19. After the refrigerant is depressurized by the indoor expansion valve 8, it flows into the heat absorber 9 and evaporates. Since the moisture in the air blown out from the indoor blower 27 by the heat absorption action at this time condenses and adheres to the heat absorber 9, the air is cooled and dehumidified.
The refrigerant evaporated in the heat absorber 9 reaches the accumulator 12 through the refrigerant pipe 13C through the internal heat exchanger 19, and repeats circulation that is sucked into the compressor 2 there through. In this dehumidifying and cooling mode, the controller 32 does not energize the auxiliary heater 23, so the air cooled by the heat absorber 9 is reheated in the process of passing through the radiator 4 (the heat dissipation capability is lower than that during heating). The As a result, dehumidifying and cooling in the passenger compartment is performed.
The controller 32 controls the rotational speed of the compressor 2 based on the temperature of the heat absorber 9 (heat absorber temperature Te) detected by the heat absorber temperature sensor 48, and also uses the outdoor expansion valve based on the high pressure of the refrigerant circuit R described above. 6 is controlled to control the refrigerant pressure of the radiator 4 (radiator pressure PCI).
(4) Cooling Mode Next, in the cooling mode, the controller 32 fully opens the valve opening degree of the outdoor expansion valve 6 in the dehumidifying and cooling mode. The controller 32 controls the air mix damper 28, and the air in the air flow passage 3 after being blown out from the indoor blower 27 and passing through the heat absorber 9 as shown by a solid line in FIG. The rate of ventilation through the vessel 4 is adjusted. Further, the controller 32 does not energize the auxiliary heater 23.
As a result, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 flows into the radiator 4 from the refrigerant pipe 13G via the electromagnetic valve 30, and the refrigerant exiting the radiator 4 passes through the refrigerant pipe 13E and the outdoor expansion valve 6. To. At this time, since the outdoor expansion valve 6 is fully opened, the refrigerant passes through it and flows into the outdoor heat exchanger 7 as it is, where it is cooled by air or by outside air that is ventilated by the outdoor blower 15 and condensed. Liquefaction. The refrigerant that has exited the outdoor heat exchanger 7 sequentially flows from the refrigerant pipe 13 </ b> A through the electromagnetic valve 17 into the receiver dryer unit 14 and the supercooling unit 16. Here, the refrigerant is supercooled.
The refrigerant that has exited the supercooling section 16 of the outdoor heat exchanger 7 enters the refrigerant pipe 13 </ b> B, reaches the indoor expansion valve 8 through the internal heat exchanger 19. After the refrigerant is depressurized by the indoor expansion valve 8, it flows into the heat absorber 9 and evaporates. The air blown out from the indoor blower 27 by the heat absorption action at this time is cooled. Further, moisture in the air condenses and adheres to the heat absorber 9.
The refrigerant evaporated in the heat absorber 9 reaches the accumulator 12 through the refrigerant pipe 13C through the internal heat exchanger 19, and repeats circulation that is sucked into the compressor 2 there through. Since the air cooled and dehumidified by the heat absorber 9 is blown into the vehicle interior from the air outlet 29 (partly passes through the radiator 4 to exchange heat), the vehicle interior is thereby cooled. become. In this cooling mode, the controller 32 rotates the compressor 2 based on the temperature of the heat absorber 9 (heat absorber temperature Te) detected by the heat absorber temperature sensor 48 and the target heat absorber temperature TEO that is the target value. To control.
(5) MAX cooling mode (maximum cooling mode)
Next, in the MAX cooling mode as the maximum cooling mode, the controller 32 opens the electromagnetic valve 17 and closes the electromagnetic valve 21. Further, the electromagnetic valve 30 is closed, the electromagnetic valve 40 is opened, and the valve opening degree of the outdoor expansion valve 6 is fully closed. Then, the compressor 2 and the blowers 15 and 27 are operated, and the air mix damper 28 keeps the air in the air flow passage 3 from passing through the auxiliary heater 23 and the radiator 4 as shown in FIG. However, there is no problem even if it is ventilated somewhat. Further, the controller 32 does not energize the auxiliary heater 23.
Accordingly, the high-temperature and high-pressure gas refrigerant discharged from the compressor 2 to the refrigerant pipe 13G flows into the bypass pipe 35 without going to the radiator 4, passes through the electromagnetic valve 40, and is connected to the refrigerant pipe on the downstream side of the outdoor expansion valve 6. 13E. At this time, since the outdoor expansion valve 6 is fully closed, the refrigerant flows into the outdoor heat exchanger 7. The refrigerant flowing into the outdoor heat exchanger 7 is cooled and condensed by running there or by the outside air ventilated by the outdoor blower 15. The refrigerant that has exited the outdoor heat exchanger 7 sequentially flows from the refrigerant pipe 13 </ b> A through the electromagnetic valve 17 into the receiver dryer unit 14 and the supercooling unit 16. Here, the refrigerant is supercooled.
The refrigerant that has exited the supercooling section 16 of the outdoor heat exchanger 7 enters the refrigerant pipe 13 </ b> B, reaches the indoor expansion valve 8 through the internal heat exchanger 19. After the refrigerant is depressurized by the indoor expansion valve 8, it flows into the heat absorber 9 and evaporates. The air blown out from the indoor blower 27 by the heat absorption action at this time is cooled. In addition, since moisture in the air condenses and adheres to the heat absorber 9, the air in the air flow passage 3 is dehumidified. The refrigerant evaporated in the heat absorber 9 reaches the accumulator 12 through the refrigerant pipe 13C through the internal heat exchanger 19, and repeats circulation that is sucked into the compressor 2 there through. At this time, since the outdoor expansion valve 6 is fully closed, similarly, it is possible to suppress or prevent the disadvantage that the refrigerant discharged from the compressor 2 flows backward from the outdoor expansion valve 6 into the radiator 4. . Thereby, the fall of a refrigerant | coolant circulation amount can be suppressed or eliminated and air-conditioning capability can be ensured now.
Here, since the high-temperature refrigerant flows through the radiator 4 in the cooling mode described above, direct heat conduction from the radiator 4 to the HVAC unit 10 occurs not a little, but in this MAX cooling mode, the refrigerant flows into the radiator 4. Therefore, the air in the air flow passage 3 from the heat absorber 9 is not heated by the heat transmitted from the radiator 4 to the HVAC unit 10. Therefore, powerful cooling of the passenger compartment is performed, and particularly in an environment where the outside air temperature Tam is high, the passenger compartment can be quickly cooled to realize comfortable air conditioning in the passenger compartment. Also in this MAX cooling mode, the controller 32 rotates the compressor 2 based on the temperature of the heat absorber 9 (heat absorber temperature Te) detected by the heat absorber temperature sensor 48 and the target heat absorber temperature TEO that is the target value. Control the number.
(6) Switching of operation mode The air flowing through the air flow passage 3 is cooled by the heat absorber 9 and heated by the heat radiator 4 (and the auxiliary heater 23) in each of the operation modes (adjusted by the air mix damper 28). ) And is blown out from the air outlet 29 into the passenger compartment. The controller 32 is set by the air-conditioning operation unit 53, the outside air temperature Tam detected by the outside air temperature sensor 33, the temperature in the vehicle interior detected by the inside air temperature sensor 37, the blower voltage, the amount of solar radiation detected by the solar radiation sensor 51, and the like. The target blowout temperature TAO is calculated based on the target passenger compartment temperature (set temperature) in the passenger compartment, and the temperature of the air blown from the blowout port 29 is controlled to this target blowout temperature TAO by switching each operation mode.
In this case, the controller 32 determines whether the outside air temperature Tam, the humidity in the vehicle interior, the target outlet temperature TAO, the radiator temperature TH, the target radiator temperature TCO, the heat absorber temperature Te, the target heat absorber temperature TEO, or the dehumidification request in the vehicle interior. By switching each operation mode based on parameters such as, etc., it switches between heating mode, dehumidifying heating mode, dehumidifying cooling mode, cooling mode and MAX cooling mode accurately according to the environmental conditions and necessity of dehumidification. In addition, efficient cabin air conditioning is realized.
(7) Noise improvement control at the time of switching from the cooling mode to the MAX cooling mode Next, referring to FIG. 4, the operation mode of the vehicle air conditioner 1 is changed from the cooling mode to the MAX cooling mode (maximum cooling mode). An example of the noise improvement control executed by the controller 32 when switching to) will be described. The timing chart of FIG. 4 shows the pressure difference ΔPdx before and after the electromagnetic valve 40 (second opening / closing valve of the present invention) when switching from the cooling mode to the MAX cooling mode, and the electromagnetic valve 30 (first opening / closing of the present invention). The pressure difference ΔPix before and after the valve), the rotational speed NC of the compressor 2, and the states of the outdoor expansion valve 6, the electromagnetic valve 40, and the electromagnetic valve 30 are shown.
The pressure difference ΔPdx before and after the solenoid valve 40 is equal to the pressure Pd on the refrigerant upstream side (front) of the solenoid valve 40 detected by the discharge pressure sensor 42 and the outdoor heat exchanger 7 detected by the outdoor heat exchanger temperature sensor 54. The outdoor heat exchanger pressure PXO on the refrigerant downstream side (rear) of the solenoid valve 40 converted from the refrigerant temperature (outdoor heat exchanger temperature TXO) immediately after coming out of the refrigerant (outdoor heat exchanger pressure sensor 56 as in the embodiment) If it is provided, it is the difference (ΔPdx = Pd−PXO) from the outdoor heat exchanger pressure PCO detected by the outdoor heat exchanger pressure sensor 56, and is calculated by the controller 32.
Further, the pressure difference ΔPix before and after the solenoid valve 30 is the refrigerant upstream side (front) pressure Pd of the solenoid valve 30 detected by the discharge pressure sensor 42 and the coolant downstream side of the solenoid valve 30 detected by the radiator pressure sensor 47. This is the difference (ΔPix = Pd−PCI) from the radiator pressure PCI, which is the (rear) pressure, and this is also calculated by the controller 32 (the same applies to the following noise improvement control).
(7-1) Noise improvement control at the time of switching from the cooling mode to the MAX cooling mode (part 1)
When the operation mode is switched from the cooling mode to the MAX cooling mode, the pressure difference ΔPdx before and after the electromagnetic valve 40 is a large value as shown in FIG. 4 in the cooling mode. Therefore, when the electromagnetic valve 40 that is closed in the cooling mode is opened to enter the MAX cooling mode with such a pressure difference, the direction from the discharge side of the compressor 2 through the electromagnetic valve 40 to the inlet side of the outdoor heat exchanger 7 Then, the refrigerant suddenly flows through the bypass pipe 35, and a large noise (noise) is generated in the solenoid valve 40.
Therefore, the controller 32 executes noise improvement control described below when switching the operation mode from the cooling mode to the MAX cooling mode. That is, when the controller 32 switches from the cooling mode to the MAX cooling mode, before the operation mode is switched, in the embodiment, the pressure difference Pdx before and after the electromagnetic valve 40 is less than or equal to a predetermined value A (for example, 0.2 MPa). Then, the rotational speed NC of the compressor 2 is adjusted (controlled in a decreasing direction). By controlling the rotation speed NC of the compressor 2 to decrease, the discharge pressure Pd decreases, so the pressure difference Pdx before and after the electromagnetic valve 40 decreases.
When the pressure difference ΔPdx is reduced below the predetermined value A in FIG. 4, the controller 32 opens the electromagnetic valve 40, closes the electromagnetic valve 30, and fully closes the outdoor expansion valve 6. Transition to mode air conditioning operation.
(7-2) Noise improvement control at the time of switching from the cooling mode to the MAX cooling mode (part 2)
Here, in the noise improvement control of the above embodiment, the controller 32 controls the rotational speed NC of the compressor 2 so that the pressure difference ΔPdx before and after the solenoid valve 40 is equal to or less than the predetermined value A. Instead, the rotation speed NC of the compressor 2 may be set to a predetermined rotation speed NC1 (FIG. 4, for example, 800 rpm to 3000 rpm) which is a predetermined low value. By controlling the rotational speed NC of the compressor 2 to a low predetermined rotational speed NC1, the discharge pressure Pd decreases, so the pressure difference Pdx before and after the electromagnetic valve 40 decreases. In this case as well, when the pressure difference ΔPdx is reduced to the predetermined value A or less, the controller 32 opens the electromagnetic valve 40, closes the electromagnetic valve 30, and fully closes the outdoor expansion valve 6, thereby increasing the MAX. Transition to air conditioning operation in cooling mode.
(7-3) Noise improvement control at the time of switching from the cooling mode to the MAX cooling mode (part 3)
Further, the compressor 2 may be stopped by the controller 32 in the noise improvement control. When the compressor 2 stops, the pressure in the refrigerant circuit R approaches an equilibrium state (the high-pressure side pressure decreases and the low-pressure side pressure increases), so the pressure difference ΔPdx before and after the electromagnetic valve 40 also decreases. Also in this case, when the pressure difference ΔPdx is reduced to the predetermined value A or less, the controller 32 opens the electromagnetic valve 40, closes the electromagnetic valve 30, closes the outdoor expansion valve 6 and closes the compressor 2. By starting, the air conditioning operation in the MAX cooling mode is started.
As described above, when switching from the cooling mode to the MAX cooling mode, the controller 32 reduces the pressure difference ΔPdx before and after the solenoid valve 40, then opens the solenoid valve 40, closes the solenoid valve 30, and opens the outdoor expansion valve 6. Since the noise improvement control for fully closing is executed, when switching from the cooling mode to the MAX cooling mode, when the solenoid valve 40 is opened, the refrigerant suddenly flows through the bypass pipe 35 toward the outdoor heat exchanger 7 side. Can be significantly suppressed or eliminated. As a result, when switching from the cooling mode to the MAX cooling mode, noise generated when the electromagnetic valve 40 is opened can be eliminated or reduced.
In particular, in each of the above noise improvement controls (noise improvement control at the time of switching from the cooling mode to the MAX cooling mode (part 1) to (part 3)), the controller 32 controls the rotational speed NC of the compressor 2 or When the compressor 2 is stopped, the pressure difference ΔPdx before and after the electromagnetic valve 40 is reduced, and when the pressure difference ΔPdx becomes a predetermined value A or less, the electromagnetic valve 40 is opened, the electromagnetic valve 30 is closed, and the outdoor Since the expansion valve 6 is fully closed, in the noise improvement control when the operation mode is switched, the pressure difference ΔPdx before and after the solenoid valve 40 is reduced by reducing the pressure (Pd) on the refrigerant upstream side of the solenoid valve 40. Can be effectively reduced, the mode can be quickly switched to the MAX cooling mode, and noise generated at the time of switching can be eliminated or reduced accurately.
Further, before switching from the cooling mode to the MAX cooling mode, that is, before the electromagnetic valve 30 is closed and the outdoor expansion valve 6 is fully closed, the rotational speed NC of the compressor 2 is reduced or stopped. It is also possible to reduce the amount of refrigerant that has fallen into the radiator 4 at the time of switching to the MAX cooling mode. As a result, it is possible to secure the refrigerant circulation amount in the refrigerant circuit R during execution of the MAX cooling mode, and to suppress or prevent a decrease in capacity.
(7-4) Noise improvement control at the time of switching from the cooling mode to the MAX cooling mode (part 4)
In the noise improvement control (noise improvement control at the time of switching from the cooling mode to the MAX cooling mode (part 3)), the pressure difference ΔPdx before and after the solenoid valve 40 after the compressor 2 is stopped is equal to or less than a predetermined value A. In this case, the solenoid valve 40 is opened. However, the present invention is not limited to this, and after the compressor 2 is stopped, the solenoid valve 40 is opened after a predetermined time (for example, 10 seconds) has elapsed. 30 may be closed and the outdoor expansion valve 6 may be fully closed, and the compressor 2 may be activated to start the air conditioning operation in the MAX cooling mode.
Thus, even if the controller 32 stops the compressor 2 in the noise improvement control, the electromagnetic valve 40 is opened after the predetermined time has elapsed, the electromagnetic valve 30 is closed, and the outdoor expansion valve 6 is fully closed. In noise improvement control when switching modes, the pressure Pd upstream of the refrigerant of the solenoid valve 40 is reduced to effectively reduce the pressure difference Pdx before and after the solenoid valve 40, and noise generated at the time of switching is eliminated accurately, or Can be reduced.
(8) Noise improvement control at the time of switching from the MAX cooling mode to the cooling mode Next, referring to FIG. 5, the operation mode of the vehicle air conditioner 1 is changed from the above-described MAX cooling mode (maximum cooling mode) to cooling. An example of the noise improvement control executed by the controller 32 when switching to the mode will be described. The timing chart of FIG. 5 shows the pressure difference ΔPdx before and after the electromagnetic valve 40 (second opening / closing valve of the present invention) when switching from the MAX cooling mode to the cooling mode, and the electromagnetic valve 30 (first opening / closing of the present invention). The pressure difference ΔPix before and after the valve), the rotational speed NC of the compressor 2, and the states of the outdoor expansion valve 6, the electromagnetic valve 40, and the electromagnetic valve 30 are shown. The controller 32 calculates the pressure difference ΔPdx before and after the solenoid valve 40 and the pressure difference ΔPix before and after the solenoid valve 30 in the same manner as described above (in the case of FIG. 4).
(8-1) Noise improvement control at the time of switching from the MAX cooling mode to the cooling mode (part 1)
When the operation mode is switched from the MAX cooling mode to the cooling mode, in the MAX cooling mode, the pressure difference ΔPix before and after the electromagnetic valve 30 has a large value as shown in FIG. Therefore, when the electromagnetic valve 30 that is closed in the MAX cooling mode is opened to enter the cooling mode with such a pressure difference, the refrigerant flows from the discharge side of the compressor 2 to the inlet side of the radiator 4 via the electromagnetic valve 30. The refrigerant rapidly flows in the pipe 13G, and a large noise (noise) is generated in the solenoid valve 30.
Therefore, the controller 32 executes the noise improvement control described below also when switching the operation mode from the MAX cooling mode to the cooling mode. That is, when the controller 32 switches from the MAX cooling mode to the cooling mode, before the operation mode is switched, in the embodiment, the pressure difference Pix before and after the solenoid valve 30 is equal to or less than a predetermined value A (for example, 0.2 MPa). The valve opening of the outdoor expansion valve 6 is opened from the fully closed state toward the fully open state. When the outdoor expansion valve 6 is opened, the discharge side of the compressor 2 and the outlet side of the radiator 4 are communicated with each other via the electromagnetic valve 40 and the outdoor expansion valve 6, and the radiator pressure PCI is increased and the discharge pressure Pd is increased. The pressure difference ΔPix before and after the solenoid valve 30 that is the difference (ΔPix = Pd−PCI) from the above becomes smaller.
When the pressure difference ΔPix is reduced below the predetermined value A in FIG. 5, the controller 32 opens the electromagnetic valve 30 and closes the electromagnetic valve 40. The outdoor expansion valve 6 is fully opened before the pressure difference ΔPix becomes equal to or less than the predetermined value A, or when the pressure difference ΔPix becomes equal to or less than the predetermined value A, but is fully opened at the same time or thereafter. Become. Thereby, it transfers to the air-conditioning driving | operation of air_conditioning | cooling mode.
(8-2) Noise improvement control at the time of switching from the MAX cooling mode to the cooling mode (part 2)
Here, when the pressure difference ΔPix is difficult to decrease in the noise improvement control of the above embodiment (noise improvement control at the time of switching from the MAX cooling mode to the cooling mode (1)), the control of the outdoor expansion valve 6 according to need is performed. In addition to this, the controller 32 may control (adjust) the rotational speed NC of the compressor 2 to decrease, or the compressor 2 may be stopped. When stopping, the compressor 2 is started at the time of shifting to the cooling mode.
(8-3) Noise improvement control at the time of switching from the MAX cooling mode to the cooling mode (part 3)
In addition, before switching from the MAX cooling mode to the cooling mode by the controller 32 in the noise improvement control, the valve opening degree of the outdoor expansion valve 6 is changed from the fully closed state to the fully opened state, and when the electromagnetic valve 30 is fully opened, It may be determined whether the pressure difference Pix before and after is equal to or less than a predetermined value A.
In that case, if the pressure difference Pix before and after the solenoid valve 30 is less than or equal to the predetermined value A when the valve opening degree of the outdoor expansion valve 6 is fully opened, the solenoid valve 30 is opened and the solenoid valve 40 is turned on. Close and enter cooling mode. On the other hand, when the pressure difference Pix before and after the electromagnetic valve 30 is still higher than the predetermined value A when the outdoor expansion valve 6 is fully opened, the controller 32 controls the rotational speed NC of the compressor 2 to decrease ( Adjustment). Also in this case, when the pressure difference ΔPix becomes equal to or less than the predetermined value A, the solenoid valve 30 is opened, the solenoid valve 40 is closed, and the cooling mode is entered.
As described above, when the controller 32 switches from the MAX cooling mode to the cooling mode, the controller 32 executes the noise improvement control that opens the solenoid valve 30 and closes the solenoid valve 40 after reducing the pressure difference ΔPix before and after the solenoid valve 30. Therefore, when switching from the MAX cooling mode to the cooling mode, when the electromagnetic valve 30 is opened, it is possible to greatly suppress or eliminate the sudden flow of the refrigerant toward the radiator 4 side. As a result, it is possible to eliminate or reduce noise generated when the electromagnetic valve 30 is opened when switching from the MAX cooling mode to the cooling mode.
In particular, in the noise improvement control at the time of switching from the MAX cooling mode to the cooling mode (part 1), the controller 32 opens the outdoor expansion valve 6 to reduce the pressure difference ΔPix before and after the electromagnetic valve 30 and to reduce the pressure difference. When ΔPix becomes a predetermined value A or less (as in noise improvement control at the time of switching from the MAX cooling mode to the cooling mode (part 3)), the pressure difference ΔPix is changed when the outdoor expansion valve 6 is fully opened. Since the electromagnetic valve 30 is opened and the electromagnetic valve 40 is closed, the refrigerant of the electromagnetic valve 30 is used in the noise improvement control when the operation mode is switched. By increasing the pressure on the downstream side (heatsink pressure PCI), the pressure difference ΔPix before and after the solenoid valve 30 is effectively reduced, and the cooling mode is quickly switched to. Accurately eliminate the noise produced in, or made so that it is possible to reduce.
Furthermore, in the noise improvement control (No. 2) and (No. 3) at the time of switching from the MAX cooling mode to the cooling mode, the controller 32 controls the rotational speed NC of the compressor 2 as necessary, or When the pressure difference ΔPix before and after the solenoid valve 30 is reduced by stopping the compressor 2, or when the pressure difference ΔPix before and after the solenoid valve 30 is higher than the predetermined value A when the outdoor expansion valve 6 is fully opened. In addition, since the pressure difference ΔPix before and after the electromagnetic valve 30 is reduced by controlling the rotational speed of the compressor 2, the pressure difference ΔPix before and after the electromagnetic valve 30 can be reduced more quickly and effectively. Will be able to.
(9) Noise improvement control when operation is stopped from the MAX cooling mode Next, referring to FIG. 6, when the operation of the vehicle air conditioner 1 is stopped from the above-described MAX cooling mode (maximum cooling mode). Next, an example of noise improvement control executed by the controller 32 will be described. The timing chart of FIG. 6 shows the pressure difference ΔPdx before and after the solenoid valve 40 (second on-off valve of the present invention) when the operation is stopped from the MAX cooling mode, and the solenoid valve 30 (first on-off valve of the present invention). ), The rotational speed NC of the compressor 2, the state of the outdoor expansion valve 6, the electromagnetic valve 40, and the electromagnetic valve 30.
The controller 32 calculates the pressure difference ΔPdx before and after the solenoid valve 40 and the pressure difference ΔPix before and after the solenoid valve 30 in the same manner as described above (in the case of FIG. 4). The solenoid valve 30 (the first on-off valve of the present invention) is a so-called normally open solenoid valve that closes when energized and opens in a non-energized state, and the solenoid valve 40 (the second on-off valve of the present invention) It is a so-called normally closed solenoid valve that opens when energized and closes when not energized.
(9-1) Noise improvement control when stopping operation from MAX cooling mode (part 1)
When the operation is stopped from the MAX cooling mode, the pressure difference ΔPix before and after the solenoid valve 30 is a large value as shown in FIG. 6 in the MAX cooling mode. Further, the solenoid valve 30 is opened in a non-energized state (operation stop). Therefore, when the solenoid valve 30 that is closed in the MAX cooling mode is opened without being energized (operation stopped) with such a pressure difference, from the discharge side of the compressor 2 through the solenoid valve 30 to the inlet side of the radiator 4. Thus, the refrigerant suddenly flows in the refrigerant pipe 13G in the direction of, and similarly, a large noise (noise) is generated in the electromagnetic valve 30.
Therefore, the controller 32 executes the noise improvement control described below even when the operation is stopped from the MAX cooling mode. That is, when stopping the operation from the MAX cooling mode, the controller 32 first stops the compressor 2 and stops the outdoor expansion valve 6 from the fully closed state to the fully opened state before stopping the operation. Go. Since the compressor 2 is stopped and the outdoor expansion valve 6 is opened, the pressure in the refrigerant circuit R approaches an equilibrium state (the high-pressure side pressure is lowered and the low-pressure side pressure is raised), so that the pressure difference ΔPix before and after the electromagnetic valve 30 Also getting smaller.
In the embodiment, when the pressure difference ΔPix becomes equal to or less than a predetermined value A (for example, 0.2 MPa), the controller 32 stops the operation by deenergizing the solenoid valve 30 and the solenoid valve 40. The solenoid valve 30 is opened by de-energization, and the solenoid valve 40 is closed. Thus, when the solenoid valve 30 is closed in the energized state and opened in the non-energized state, the controller 32 reduces the pressure difference ΔPix before and after the solenoid valve 30 when stopping the operation from the MAX cooling mode. Since the noise improvement control for deenergizing the solenoid valve 30 is executed, when the operation is stopped from the MAX cooling mode, when the solenoid valve 30 is deenergized and the solenoid valve 30 is opened, the radiator 4 is moved toward the radiator 4 side. It is possible to greatly suppress or eliminate the rapid flow of the refrigerant. As a result, when the operation is stopped from the MAX cooling mode, it is possible to eliminate or reduce the noise generated by the opening of the electromagnetic valve 30.
In particular, in the above embodiment, the controller 32 stops the compressor 2 and opens the outdoor expansion valve 6 to reduce the pressure difference ΔPix before and after the electromagnetic valve 30, and the pressure difference ΔPix becomes a predetermined value A or less. In this case, the solenoid valve 30 is deenergized. Therefore, in the noise improvement control when the operation is stopped from the MAX cooling mode, the pressure difference ΔPix before and after the solenoid valve 30 is effectively reduced, and the solenoid valve is quickly 30 can be de-energized, and noise generated at the time of stopping can be accurately eliminated or reduced.
(9-2) Noise improvement control when operation is stopped from the MAX cooling mode (part 2)
Here, in addition to the above embodiment (noise improvement control when stopping operation from the MAX cooling mode (part 1)), for example, in the noise improvement control when the controller 32 stops operation from the MAX cooling mode, The compressor 2 is stopped, the outdoor expansion valve 6 is fully opened, and it is determined whether or not the pressure difference ΔPix before and after the electromagnetic valve 30 is equal to or less than a predetermined value A when the outdoor expansion valve 6 is fully opened. You may do it. In that case, when the pressure difference ΔPix is equal to or smaller than the predetermined value A, the solenoid valve 30 is deenergized. On the other hand, when the pressure difference Pix is higher than the predetermined value A, the electromagnetic valve 30 is de-energized when the pressure difference Pix drops below the predetermined value A.
(9-3) Noise improvement control when operation is stopped from the MAX cooling mode (part 3)
Alternatively, when the outdoor expansion valve 6 is fully opened, it is determined whether or not the pressure difference ΔPix before and after the electromagnetic valve 30 is equal to or less than a predetermined value A. If the pressure difference ΔPix is equal to or less than the predetermined value A, the electromagnetic valve 30 When the pressure difference Pix is higher than the predetermined value A, the solenoid valve 30 may be deenergized after a predetermined time has elapsed.
With these (noise improvement control when the operation is stopped from the MAX cooling mode (part 2), (part 3)), the pressure before and after the solenoid valve 30 in the noise improvement control when the operation is stopped from the MAX cooling mode. The difference ΔPix can be effectively reduced, the solenoid valve 30 can be quickly de-energized, and the noise generated when stopped can be eliminated or reduced accurately.
In the embodiment, the present invention is applied to the vehicle air conditioner 1 that switches and executes each operation mode of the heating mode, the dehumidifying heating mode, the dehumidifying cooling mode, the cooling mode, and the MAX cooling mode. The present invention is also effective for a vehicle air conditioner that performs switching between the cooling mode and the MAX cooling mode.
Further, the switching control of each operation mode shown in the embodiment is not limited thereto, and the outside air temperature Tam, the humidity in the vehicle interior, the target blowing temperature TAO, depending on the capability and usage environment of the vehicle air conditioner, Adopt any one of parameters such as radiator temperature TH, target radiator temperature TCO, heat absorber temperature Te, target heat absorber temperature TEO, presence / absence of dehumidification request in vehicle interior, or a combination thereof, or all of them. Appropriate conditions should be set.
Further, the auxiliary heating device is not limited to the auxiliary heater 23 shown in the embodiment, and a heat medium circulation circuit that heats the air in the air flow passage by circulating the heat medium heated by the heater or an engine. You may utilize the heater core etc. which circulate through the heated radiator water. Further, the configuration of the refrigerant circuit R described in each of the above embodiments is not limited thereto, and it is needless to say that the refrigerant circuit R can be changed without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Vehicle air conditioner 2 Compressor 3 Air flow path 4 Radiator 6 Outdoor expansion valve 7 Outdoor heat exchanger 8 Indoor expansion valve 9 Heat absorber 23 Auxiliary heater (auxiliary heating device)
27 Indoor blower
28 Air mix damper 30 Solenoid valve (first on-off valve)
40 Solenoid valve (second on-off valve)
31 Outlet switching damper 32 Controller (control device)
35 Bypass piping 45 Bypass device R Refrigerant circuit

Claims (9)

1. A compressor for compressing the refrigerant;
   An air flow passage through which air to be supplied into the passenger compartment flows;
   A radiator for radiating the refrigerant to heat the air supplied from the air flow passage to the vehicle interior;
   A heat absorber for absorbing the refrigerant and cooling the air supplied from the air flow passage to the vehicle interior;
   An outdoor heat exchanger provided outside the vehicle compartment;
   An outdoor expansion valve for decompressing the refrigerant flowing out of the radiator and flowing into the outdoor heat exchanger;
   A first on-off valve provided between the discharge side of the compressor and the inlet side of the radiator;
   A bypass pipe for branching upstream of the first on-off valve, bypassing the radiator and the outdoor expansion valve, and allowing the refrigerant discharged from the compressor to flow to the outdoor heat exchanger;
   A second on-off valve provided in the bypass pipe;
   Equipped with a control device,
   The control device opens the first on-off valve and closes the second on-off valve, thereby allowing the refrigerant discharged from the compressor to flow from the radiator to the outdoor heat exchanger so that the outdoor heat exchange is performed. A cooling mode in which heat is dissipated in the cooler, and after the decompressed refrigerant is depressurized, the heat absorber absorbs heat; and
   The outdoor expansion valve is fully closed, the first on-off valve is closed, and the second on-off valve is opened, so that the refrigerant discharged from the compressor flows to the outdoor heat exchanger through the bypass pipe. In a vehicle air conditioner that performs heat dissipation and switches and executes a maximum cooling mode in which heat is absorbed by the heat absorber after decompressing the radiated refrigerant.
   When the control device switches from the cooling mode to the maximum cooling mode, after reducing the pressure difference before and after the second on-off valve, the control device opens the second on-off valve, closes the first on-off valve, A vehicle air conditioner that performs noise improvement control for fully closing the outdoor expansion valve.
2. In the noise improvement control, the control device controls the rotation speed of the compressor or stops the compressor to reduce the pressure difference before and after the second on-off valve, so that the pressure difference is predetermined. 2. The vehicle air conditioner according to claim 1, wherein when the value is equal to or lower than the value, the second on-off valve is opened, the first on-off valve is closed, and the outdoor expansion valve is fully closed. apparatus.
3. In the noise improvement control, the control device stops the compressor, opens the second on-off valve after a predetermined time, closes the first on-off valve, and fully closes the outdoor expansion valve. The vehicle air conditioner according to claim 1.
4. A compressor for compressing the refrigerant;
   An air flow passage through which air to be supplied into the passenger compartment flows;
   A radiator for radiating the refrigerant to heat the air supplied from the air flow passage to the vehicle interior;
   A heat absorber for absorbing the refrigerant and cooling the air supplied from the air flow passage to the vehicle interior;
   An outdoor heat exchanger provided outside the vehicle compartment;
   An outdoor expansion valve for decompressing the refrigerant flowing out of the radiator and flowing into the outdoor heat exchanger;
   A first on-off valve provided between the discharge side of the compressor and the inlet side of the radiator;
   A bypass pipe for branching upstream of the first on-off valve, bypassing the radiator and the outdoor expansion valve, and allowing the refrigerant discharged from the compressor to flow to the outdoor heat exchanger;
   A second on-off valve provided in the bypass pipe;
   Equipped with a control device,
   The control device opens the first on-off valve and closes the second on-off valve, thereby allowing the refrigerant discharged from the compressor to flow from the radiator to the outdoor heat exchanger so that the outdoor heat exchange is performed. A cooling mode in which heat is dissipated in the cooler, and after the decompressed refrigerant is depressurized, the heat absorber absorbs heat; and
   The outdoor expansion valve is fully closed, the first on-off valve is closed, and the second on-off valve is opened, so that the refrigerant discharged from the compressor flows to the outdoor heat exchanger through the bypass pipe. In a vehicle air conditioner that performs heat dissipation and switches and executes a maximum cooling mode in which heat is absorbed by the heat absorber after decompressing the radiated refrigerant.
   When the control device switches from the maximum cooling mode to the cooling mode, after reducing the pressure difference before and after the first on-off valve, the control device opens the first on-off valve and closes the second on-off valve. An air conditioner for a vehicle that performs improvement control.
5. In the noise improvement control, the control device reduces the pressure difference before and after the first on-off valve by opening the outdoor expansion valve, and when the pressure difference becomes a predetermined value or less, The vehicle air conditioner according to claim 4, wherein an on-off valve is opened and the second on-off valve is closed.
6. In the noise improvement control, the control device controls the rotational speed of the compressor, or reduces the pressure difference before and after the first on-off valve by stopping the compressor, or the outdoor expansion When the pressure difference before and after the first on-off valve is higher than the predetermined value when the valve is fully opened, the pressure difference before and after the first on-off valve is reduced by controlling the rotation speed of the compressor. The vehicle air conditioner according to claim 5, wherein
7. A compressor for compressing the refrigerant;
   An air flow passage through which air to be supplied into the passenger compartment flows;
   A radiator for radiating the refrigerant to heat the air supplied from the air flow passage to the vehicle interior;
   A heat absorber for absorbing the refrigerant and cooling the air supplied from the air flow passage to the vehicle interior;
   An outdoor heat exchanger provided outside the vehicle compartment;
   An outdoor expansion valve for decompressing the refrigerant flowing out of the radiator and flowing into the outdoor heat exchanger;
   A first on-off valve provided between the discharge side of the compressor and the inlet side of the radiator;
   A bypass pipe for branching upstream of the first on-off valve, bypassing the radiator and the outdoor expansion valve, and allowing the refrigerant discharged from the compressor to flow to the outdoor heat exchanger;
   A second on-off valve provided in the bypass pipe;
   Equipped with a control device,
   By the control device, at least the outdoor expansion valve is fully closed, the first on-off valve is closed, and the second on-off valve is opened, so that the refrigerant discharged from the compressor is passed through the bypass pipe by the bypass pipe. In a vehicle air conditioner that executes a maximum cooling mode in which the refrigerant is radiated by flowing it through a heat exchanger and the radiated refrigerant is decompressed and then absorbed by the heat absorber.
   The first on-off valve is a solenoid valve that closes in an energized state and opens in a non-energized state,
   When the control device stops from the maximum cooling mode, the control device performs noise improvement control for de-energizing the first on-off valve after reducing the pressure difference before and after the first on-off valve. A vehicle air conditioner.
8. In the noise improvement control, the control device stops the compressor and opens the outdoor expansion valve to reduce the pressure difference before and after the first on-off valve, and the pressure difference becomes a predetermined value or less. In this case, the vehicle air conditioner according to claim 7, wherein the first on-off valve is deenergized.
9. In the noise improvement control, the control device stops the compressor, fully opens the outdoor expansion valve, and when the outdoor expansion valve is fully opened, a pressure difference before and after the first on-off valve is increased. When it is less than a predetermined value, the first on-off valve is de-energized. When it is higher than the predetermined value, the first on-off valve is de-energized when it falls below the predetermined value or after a predetermined time has elapsed. The vehicle air conditioner according to claim 7.

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