JPH07132729A - Air conditioner - Google Patents

Abstract

PURPOSE:To prevent heating efficiency from worsening in a heat exchanger by opening/closing a bypass passage in a prescribed condition to limit a refrigerant flow from a high pressure side to a low pressure side, in the case of deciding dehumidifying warming executed by an operation mode deciding means. CONSTITUTION:In this refrigerating cycle 50, a heating heat exchanger 12 and a capillary tube 22 are connected to a delivery side 21a of a compressor 21 driven by a running engine, to provide the first bypass passage 45 to detour around the capillary tube 22. An outflow side 22b of the capillary tube 22 is connected through an out-room heat exchanger 24, liquid tank 26, temperature sensing expansion valve 27, cooling heat exchanger 10 and an accumator 29 to an inflow side 21b of the compressor 21. The second bypass passage 30 is provided to detour around the capillary tube 22 and the liquid tank 26 and the third bypass passage 33 is provided between the out-room heat exchanger 24 and the accumulator 29, respectively, to control an opening/closing valve 31 in the second bypass passage 30 at the time of deciding a dehumidifying warming mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for a vehicle, which uses an evaporator and a condenser forming a part of a cooling cycle as a cooling heat exchanger and a heating heat exchanger.

[0002]

2. Description of the Related Art In a conventional air conditioner, a device disclosed in Japanese Patent Publication No. 52-13025 is known as one in which an evaporator and a condenser are used as a cooling heat exchanger and a heating heat exchanger. Has been. However, in the air conditioner of this reference, since the flow direction of the refrigerant is switched by switching the four-way valve to switch between cooling and heating, pressure loss of the refrigerant in the four-way valve is large, and high-pressure refrigerant and low-temperature refrigerant are Since the refrigerant flows through the four-way valve at the same time, the four-way valve has a drawback that heat is exchanged.

For this reason, the present applicant has disclosed an air conditioner as shown in FIG. 7 in Japanese Patent Application No. 5-151097 filed earlier. The air conditioner of this reference is arranged with a compressor, a first heat exchanger 102 arranged in an air conditioning duct 101, and an upstream side of the first heat exchanger 102 in the air conditioning duct 101. A second heat exchanger 103 and a third heat exchanger arranged outside the air conditioning duct 101.
Heat exchanger 104 and first and second expansion devices 105,
And 106. Further, in this air conditioner, from the compressor 107 to the first heat exchanger 10
2, the first expansion device 105, the third heat exchanger 1
04, the on-off valve 112, the second expansion device 106, and the second heat exchanger 103 are connected in this order to form a loop, and the inflow side 105a of the first expansion device 105 is further formed.
And the outflow side 105b, and a passage 109 that is opened and closed by an on-off valve 108, the outflow side 102b of the first heat exchanger.
And a third passage 111 that communicates between the second expansion device and the inflow side 106a of the second expansion device, and is opened and closed by an opening / closing valve 110;
A passage 114 is provided that connects the outflow side 104b of the heat exchanger 104 and the suction side B of the compressor and is opened and closed by an on-off valve 113.

[0004]

However, in the air conditioner configured as described above, a temperature-sensitive expansion valve is used as the second expansion device in order to execute the optimum cooling cycle operation, and the on-off valve 108, 112 is closed and the on-off valve 11
When the dehumidifying and heating operation is executed by opening 0 and 113, the refrigerant pressure-fed from the compressor 107 radiates heat while passing through the first heat exchanger 102 and is condensed. Since the on-off valve 108 is closed, the condensed refrigerant passes through the first expansion device 105, is decompressed and expanded to the third heat exchanger 104, and the on-off valve 110 is opened. Through the second expansion device (temperature-sensitive expansion valve) 106, is decompressed and expanded to reach the second heat exchanger 103, and absorbs heat in the second and third heat exchangers 103 and 104. Then, it evaporates and returns to the compressor 107.

As a result, in the air conditioning duct 101, the air passing through the second heat exchanger 103 is cooled and dehumidified, and is heated by passing through the first heat exchanger 102. In this case, the heating amount in the first heat exchanger 102 may be larger than the cooling amount in the second heat exchanger 103 because the cooling amount in the second heat exchanger 103 may be divided from the third heat exchanger 104. Therefore, the blown air is dehumidified and heated.

However, when the outside air temperature (air temperature flowing through the third heat exchanger) is low and the inside air temperature (air temperature flowing through the first and second heat exchangers) is high during this dehumidifying heating, the Since the evaporation pressure in the second heat exchanger becomes high, a problem occurs in which heat is radiated to the passing air in the third heat exchanger. Also, under similar conditions,
Since the degree of superheat of the second heat exchanger 103 increases, the opening area of the second expansion device 106 is maximized by the temperature sensing cylinder (not shown) that detects this degree of superheat, and the first expansion device 1
05 and the total opening area of the second expansion device 106 increases. As a result, since the refrigerant excessively flows from the high pressure side to the low pressure side, most of the refrigerant moves to the low pressure side, which causes a problem that the normal operation of the cycle cannot be performed. Further, even if the second expansion device 106 is moderated and the normal operation of the cycle is ensured, the heating in the first heat exchanger 102 is caused because the second heat exchanger 103 is excessively cooled. It is inefficient.

For this reason, the present invention provides an air conditioner capable of maintaining a high pressure by preventing an excessive flow of the refrigerant from the high pressure side to the low pressure side which occurs under a predetermined condition during the dehumidifying and heating operation. To do.

[0008]

Therefore, the present invention is
A compressor, a heating heat exchanger connected to the discharge side of the compressor and arranged in the air conditioning duct, and a first decompression expansion means connected to the heating heat exchanger,
The inflow side and the outflow side of the first decompression expansion means are communicated with each other,
A first bypass passage opened and closed by a first opening / closing means; an outdoor heat exchanger connected to the first decompression / expansion means and arranged outside the air conditioning duct; Second decompression expansion means connected via two opening / closing means or one-way valve (check valve), and the heating heat connected to the second decompression expansion means and in the air conditioning duct. A cooling heat exchanger arranged on the upstream side of the exchanger, between the heating heat exchanger and the first decompression expansion means,
The second opening / closing means or one-way valve (check valve) and the second
And a second bypass passage having a third opening / closing means, the outdoor heat exchanger, and the second opening / closing means or one-way valve (check valve). And a third bypass passage having a fourth opening / closing means, which communicates with the intake side of the compressor, and determines whether the operation mode of the air conditioner is the dehumidification heating mode. An operation mode determination means and a bypass passage for controlling the third opening / closing means so as to open / close the second bypass passage under a predetermined condition when the operation mode determination means determines that the dehumidifying / heating mode is set. The opening and closing means is provided.

[0009]

Therefore, according to the present invention, when the operation mode determining means determines that the dehumidifying heating is being performed, the third bypass means opens and closes the second bypass passage under a predetermined condition, thereby increasing the high pressure. The above problem can be achieved in order to limit the flow of the refrigerant from the side to the low pressure side.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

A vehicle air conditioner 1 shown in FIG.
Is an intake door 6 in which the inside air introduction port 3 and the outside air introduction port 4 are opened at the most upstream side of the air conditioning duct 2, and the inside air introduction port 3 and the outside air introduction port 4 are appropriately selected and opened by being driven by an actuator 5. Has an intake unit 7, and downstream of this intake unit 7,
A blower unit 9 having a blower 8 for sending the outside air or the inside air sucked from the intake unit 7 to the downstream side.
Is provided.

A cooling heat exchanger 10 is arranged in the air conditioning duct 2 on the downstream side of the blower unit 9, and a heating heat exchanger 12 is arranged on the downstream side of the cooling heat exchanger 10. A mix door 11 for adjusting the amount of air passing through the heating heat exchanger 12 is arranged on the upstream side front surface of the heating heat exchanger 12. Further, a diff outlet 13, a vent outlet 14, and a foot outlet 15 are opened at the most downstream side of the air conditioning duct 2, and are selectively opened by a mode door 16 driven by an actuator 18.

The cooling heat exchanger 10 and the heating heat exchanger 12 together form a part of the cooling cycle 50. The cooling cycle 50 will be described below.

The cooling cycle 50 has a compressor 21 which is connected to and driven by a traveling engine (not shown) via an electromagnetic clutch 20, and a discharge side 21a of the compressor 21 has an inflow side of the heating heat exchanger 12. 12a
Are connected. Also, the outflow side 1 of this heating heat exchanger 12
2b is a capillary tube 22 as a first decompression and expansion means.
Is connected to the inflow side 22a. In addition, this capillary tube 2
A first bypass passage 45 that connects the two inflow side 22a and the outflow side 22b is provided, and is opened and closed by the solenoid valve 23.

The outflow side 22 of the capillary tube 22
The inflow side 24a of the outdoor heat exchanger 24 is connected to b, and the outflow side 24b of the outdoor heat exchanger 24 is
Inflow side 26a of liquid tank 26 via on-off valve 25
Connected to. Outflow side 26b of this liquid tank 26
Is connected to the inflow side 27a of the temperature-sensitive expansion valve 27. still,
In this embodiment, the opening / closing valve 25 is used as the second opening / closing means.
The following description will be made by using the open / close valve 25, but the same control can be performed by using a one-way valve (check valve) instead of the open / close valve 25. in this case,
The open / close control of the open / close valve 25 is omitted.

The outflow side 27b of the temperature-sensitive expansion valve 27 is connected to the inflow side 10a of the cooling heat exchanger 10, and the outflow side 10b of the cooling heat exchanger 10 is connected to the accumulator 2.
9 is connected to the inflow side 29a of the compressor 21, and the outflow side 29b of the accumulator 29 is connected to the inflow side 21 of the compressor 21.
It is connected to b. In addition, the temperature sensitive tube 2 of the temperature sensitive expansion valve 27
8 is attached to the pipe on the outflow side 10b of the cooling heat exchanger 10, and the opening degree of the expansion valve 27 is adjusted by the degree of superheat here.

The inflow side 22 of the capillary tube 22
A second bypass passage 30 is provided to connect the “a” and the upstream side 26a of the liquid tank 26. The second bypass passage 30 is provided with an opening / closing valve 31 for opening and closing the second bypass passage 30. ing.

Further, the outflow side 24 of the outdoor heat exchanger 24
b and the inflow side 29a of the accumulator 29 are connected to each other, and a third bypass passage 33 is provided, and the third bypass passage 33 is provided with an opening / closing valve 34 for opening and closing the third bypass passage 33. There is.

A control unit 40 is provided in order to control the automobile air conditioner 1 having the above structure. The control unit 40 includes a central processing unit (CPU) (not shown) and a read-only memory (RO).
M), a random access memory (RAM), an input / output port (I / O), or the like, which is known per se, and further, an output signal from this microcomputer is converted into a signal driven by each control device. A signal having at least a drive circuit, and detection signals from the outside air temperature detection sensor 41, the vehicle interior temperature detection sensor 42, the temperature of the cooling heat exchanger 10 or the blowout temperature detection sensor 43 of the cooling heat exchanger 10. , And a setting signal from the operation panel 44 is input to the control unit 40, processed by a predetermined program there, and then the control signal is passed through each drive circuit to each control device, for example, the actuator 5, 17, 18, blower. 8, the electromagnetic clutch 20, and the on-off valves 23, 25, 31, 34 are output.

In this automobile air conditioner 1, when the cooling operation is performed, the open / close valves 23 and 25 are opened, the open / close valves 31 and 34 are closed, and the mix door 11 completely covers the front surface of the heating heat exchanger 12. Closed (position C in the figure). As a result, the cooling cycle 50 includes, as shown in FIG. 2, the compressor 21, the heat exchanger 12 for heating, the first bypass passage 45, the outdoor heat exchanger 24, the open / close valve 25, the liquid tank 26, and the temperature sensitive type. The expansion valve, the cooling heat exchanger 10, and the accumulator 29 are included.

In this cooling cycle 50, the refrigerant compressed by the compressor 21 is the heat exchanger 1 for heating.
However, the air passing through the heating heat exchanger 12 is blocked by the mix door 11 that passes through 2, but heat cannot be dissipated and reaches the capillary tube 22. However, the on-off valve 23
Since the refrigerant is open, the refrigerant flows through the first bypass passage 45 having a small flow resistance to flow into the outdoor heat exchanger 24, and sufficiently radiates heat while passing through the outdoor heat exchanger 24. Then, it is condensed and becomes a high-pressure liquid refrigerant.

The high-pressure liquid refrigerant reaches the liquid tank 26 via the opening / closing valve 25 and is stored in the liquid tank 26. The refrigerant flowing out of the liquid tank 26 passes through the temperature-sensitive expansion valve 27, is decompressed and expanded, and absorbs heat and evaporates while passing through the cooling heat exchanger 10 to become a low-pressure low-temperature gas refrigerant. The gas refrigerant flows into the accumulator 29 to perform gas-liquid separation, and then is sucked into the compressor 21.

As a result, the air flowing in the air conditioning duct 2 is cooled by the cooling heat exchanger 10, but is not heated by the heating heat exchanger 12, so that cold air can be blown out. Is.

In the cooling bi-level mode or the dehumidifying cooling mode, the cooling cycle is constructed as described above, the opening of the mix door is changed, and the cooled air passes through the heating heat exchanger 12. The heating is carried out by heating, and the heating amount is adjusted by the mix door 11 to adjust it to a desired temperature.

Further, in the heating mode, as shown in FIG. 3, the on-off valves 23, 25, 31 are closed, the on-off valve 34 is opened, and the mix door 11 is fully opened (position O in the figure). Accordingly, the cooling cycle 50 is configured by the compressor 21, the heat exchanger 12 for heating, the capillary tube 22, the outdoor heat exchanger 24, the third bypass passage 33, and the accumulator 29.

In this cooling cycle 50, the refrigerant compressed by the compressor 21 is the heat exchanger 1 for heating.
While passing through 2, it radiates heat to the air passing through it to be condensed and becomes a liquid refrigerant. This liquid refrigerant is used in the capillary tube 2
After passing through 2, the pressure is expanded under reduced pressure, the heat of the air passing through the outdoor heat exchanger 24 is absorbed and evaporated, and the air flows into the accumulator 29 through the third bypass passage 33. As a result, the air passing through the air conditioning duct 2 is heated by the heating heat exchanger 12, so that heating is performed.

In the dehumidifying and heating mode, the on-off valves 23 and 25 are closed and the on-off valves 31 and 34 are opened as shown in FIG. As a result, the compressor 21, the heating heat exchanger 12, the capillary tube 22, the outdoor heat exchanger 2
4, the first bypass 60 passing through the third bypass passage 33, the second bypass passage 30, and the liquid tank 2
6, a temperature-sensitive expansion valve 27, and a second flow path 70 that passes through the cooling heat exchanger 10 to form a cooling cycle 50 from the accumulator 29 to the compressor 21.

In this cooling cycle 50, the refrigerant compressed by the compressor 21 is the heat exchanger 1 for heating.
While passing through 2, it radiates heat and condenses to become a liquid refrigerant. The liquid refrigerant is divided into the first flow path 60 and the second flow path 70, and the refrigerant flowing in the first flow path 60 is decompressed and expanded in the capillary tube 22 and absorbed in the outdoor heat exchanger 24. Evaporate.

Further, the refrigerant flowing through the second flow path 70 passes through the on-off valve 31 and the liquid tank 26 and the temperature-sensitive expansion valve 2
It is expanded under reduced pressure at 7, and absorbs heat at the cooling heat exchanger 10 to evaporate. In this case, the heat radiation amount (heating amount) in the heating heat exchanger 12 is larger than the heat absorption amount (cooling amount) in the cooling heat exchanger 10, so that the cooling heat exchanger 10 cools and dehumidifies. Since the heated air is heated by the heating heat exchanger 12 to a temperature equal to or more than the cooling amount, heating and dehumidification can be performed.

When this dehumidifying and heating mode is executed, the control of the on-off valve 31 of the dehumidifying and heating control shown in the flowchart of FIG. 5 which is the first embodiment is executed. This on-off valve 31
If the air conditioning control is determined to be the dehumidifying and heating mode by the determination of step 100 in the control of step 1, the process proceeds to step 110, and if the mode other than the dehumidifying and heating mode, the process proceeds to step 140 and the opening / closing valve is performed. The factor E controlling 31 is set to zero (E = 0).

When the dehumidifying mode is determined by the determination at step 100, at step 110, the control factor E for controlling the opening / closing valve 31 is set to a numerical value 1 or a numerical value 0 at predetermined intervals (T ₁ , T 2). ₂ ) Set with.
Note that setting the control factor E to zero (E = 0) indicates closing the on-off valve 31, and setting the control factor E to 1 (E = 1) opens the on-off valve 31. Indicates that
Further, the interval T ₁ indicates a time (valve opening time) when the on-off valve 31 is opened, and T ₂ indicates a time (valve closing time) when the on-off valve 31 is closed. Is calculated on the basis of the difference ΔT from (T ₁ = F (Δ
T), T ₂ = G (ΔT)).

Thereafter, in step 120, it is determined whether the cooling heat exchanger 10 is frozen. This determination is, for example, 1 when the blowout temperature (T _E ) of the cooling heat exchanger 10 is 2 degrees or less.
It is determined by whether or not it has continued for 0 minutes or more. If it continues for 10 minutes or more at twice or less (when there is a risk of freezing), zero is set to the control factor E in step 130. If this condition is not met, step 1
The current control is maintained by proceeding to 50. As a result, when there is a risk of freezing during the control of opening the on-off valve 31, the second bypass passage is set in step 130 so that the on-off valve 31 is closed (E = 0). Since the refrigerant passing through 30 can be blocked, the cooling heat exchanger 10 can be prevented from freezing. The control of steps 120 and 130 is
It is antifreeze control.

The steps 150, 160 and 170 will be described below.
Indicates a step of actually controlling the opening / closing of the opening / closing valve 31.
In step 150, it is judged whether or not the control factor E of the on-off valve 31 set in step 110, step 130 and step 140 is zero,
When the control factor E is 0 (Y), the routine proceeds to step 160 to close the on-off valve 31, and when the control factor E is 1 (N), the routine proceeds to step 170 to open the on-off valve 31. is there.

As a result, when it is determined in step 100 that dehumidification heating is performed, the opening / closing valve 31 is controlled to open / close at a constant cycle T (T = T ₁ + T ₂ ).
The amount of refrigerant flowing through the second bypass passage 30 can be limited. As a result, in the dehumidification heating mode,
When the intake air mode is changed from the outside air introduction mode to the inside air circulation mode, the refrigerant is excessive from the high pressure side to the low pressure side caused by the maximum opening (usually 3 mm ^{2 to} 4 mm ² ) of the temperature-sensitive expansion valve 27. It is possible to prevent the flow.

The second embodiment shown in the flowchart of FIG. 6 will be described below. The same reference numerals are given to the steps for performing the same control as in the first embodiment.

First, in step 100, as in the first embodiment, it is determined whether the air conditioning control is in the dehumidifying and heating mode. In this determination, if the dehumidifying and heating mode is not set (N), the routine proceeds to step 112, where the control factor E of the on-off valve 31 is set to zero (E = 0), and the step 15 is executed.
The on-off valve 31 is closed under the control of 0, 160, 170.

If it is determined in step 100 that the air conditioning control is in the dehumidifying and heating mode, the process proceeds to step 114, where the outside air temperature Ta and the cooling heat exchanger 10 (or the outdoor heat exchanger) are used. The temperature difference ΔTh from the temperature 24) (hereinafter referred to as the evaporation temperature) Th is determined.

When it is determined in step 114 that the temperature difference ΔTh is smaller than the predetermined value ΔTs, the routine proceeds to step 116, where the control factor E is set to zero,
When it is determined that the temperature difference ΔTh is larger than the predetermined value ΔTs + ΔH, the process proceeds to step 120, and it is determined whether or not the cooling heat exchanger 10 is in the frozen state.

When it is determined in step 120 that there is no risk of freezing, the control factor E is set to 1 in step 125, and when it is determined that there is risk of freezing, in step 130. The control factor E is set to zero.

When it is determined in step 114 that the numerical value is other than the above (others)
In step 118, it is determined whether the control factor E is zero. If the control factor E is zero (E = 0), the process proceeds to step 150 and if the control factor E is 1 (E = In step 1), the process proceeds to step 120.

By performing the above control, in step 114, the temperature difference ΔTh is brought to a predetermined value (Δ
When it is determined that the temperature difference is equal to or less than Ts), the control for closing the on-off valve 31 is executed, and the temperature difference ΔTh is the predetermined value Δ.
When it is determined that it is larger than Ts by ΔH or more (ΔTh>
As long as there is no risk of freezing, the open / close valve 3
The control for opening 1 is executed, and other values (when the temperature difference ΔTh is within the range of ΔTs to ΔH (Δ
Ts <ΔTh <ΔTs + ΔH)), the control is performed so as to maintain the current control.

As a result, during the dehumidifying and heating operation,
When the outside air temperature is lower than the evaporation temperature, or when the outside air temperature and the evaporation temperature are within a predetermined temperature, sufficient heat absorption is not performed in the outdoor heat exchanger 24, and the refrigerant remains in the liquid state on the low pressure side. Therefore, it is possible to maintain the high pressure while preventing the excessive flow of the refrigerant from the high pressure side to the low pressure side by reducing the amount of the refrigerant flowing to the low pressure side by closing the on-off valve 31 by closing the on-off valve 31. it can.
When the outside air temperature is higher than the evaporation temperature by a predetermined range or more, the opening / closing valve 31 is controlled to open, and the cooling heat exchanger 10 is operated to perform the dehumidifying and heating operation. .

[0043]

As described above, according to the present invention,
During the dehumidification heating operation, the amount of the refrigerant flowing to the cooling heat exchanger can be limited in order to open and close the second bypass passage under a predetermined condition, whereby the refrigerant excessively flows from the high pressure side to the low pressure side. Since this can be prevented and the high pressure can be maintained, stable air conditioning control, particularly stable dehumidifying and heating operation can be executed.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram illustrating a configuration of an air conditioner for a vehicle according to an embodiment of the present invention.

FIG. 2 is a schematic explanatory diagram illustrating a configuration of a cooling cycle in a cooling mode of the vehicle air conditioner according to the embodiment of the present invention.

FIG. 3 is a schematic explanatory diagram illustrating a configuration of a cooling cycle in a heating mode of the vehicle air conditioner according to the embodiment of the present invention.

FIG. 4 is a schematic explanatory diagram illustrating a configuration of a cooling cycle in a heating / dehumidifying mode of the vehicle air conditioner according to the embodiment of the present invention.

FIG. 5 is a flowchart showing the on-off valve control in the dehumidifying and heating mode according to the first embodiment of the present invention.

FIG. 6 is a flowchart showing on-off valve control in a dehumidifying and heating mode according to a second embodiment of the present invention.

FIG. 7 is a schematic explanatory diagram illustrating a configuration of a conventional vehicle air conditioner.

[Explanation of symbols]

 1 Automotive Air Conditioner 2 Air Conditioning Duct 3 Inside Air Inlet 4 Outside Air Inlet 6 Intake Door 7 Intake Unit 10 Cooling Heat Exchanger 12 Heating Heat Exchanger 21 Compressor 22 Capillary Pipe 23, 25, 31, 34 Open / close Valve 24 Outdoor heat exchanger 26 Liquid tank 27 Temperature-sensing expansion valve 28 Temperature-sensing cylinder 29 Accumulator 30 Second bypass passage 33 Third bypass passage 45 First bypass passage

Claims (1)

[Claims] 1. A compressor, a heating heat exchanger connected to a discharge side of the compressor and arranged in an air conditioning duct, and a first decompression expansion means connected to the heating heat exchanger, A first opening / closing means which connects the inflow side and the outflow side of the first decompression / expansion means and is opened / closed by the first opening / closing means.
A bypass passage, an outdoor heat exchanger connected to the first decompression / expansion means and arranged outside the air conditioning duct, the outdoor heat exchanger and the second opening / closing means or one-way valve (check valve). Second decompression / expansion means connected via a valve) and a cooling device connected to the second decompression / expansion means and arranged in the air conditioning duct on the upstream side of the heating heat exchanger. Between a heat exchanger, the heating heat exchanger and the first decompression expansion means, and between the second opening / closing means or one-way valve (check valve) and the second decompression expansion means. And a second bypass passage having a third opening / closing means, between the outdoor heat exchanger and the second opening / closing means or one-way valve (check valve), and the compressor. A third bypass passage which communicates with the suction side and has a fourth opening / closing means. When the operation mode determination means determines whether the operation mode of the summing device is the dehumidification heating mode, and when the operation mode determination means determines that the operation mode is the dehumidification heating mode, the second bypass passage is connected to the predetermined bypass path. An air conditioner comprising: a bypass passage opening / closing means for controlling the third opening / closing means so as to open / close under a condition.