JP2009002597A - Refrigeration cycle device and vehicle air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a pressure loss generated in a second evaporator 7 in a refrigeration cycle device. <P>SOLUTION: During dual operation, by an air conditioning ECU 10, a solenoid valve 5A fully opens the refrigerant outlet side of a decompression device 4 and the refrigerant inlet side of the second evaporator 7 and a solenoid valve 5B is brought into a fixed throttle state. Thus, all refrigerants flowed out of the decompression device 4 do not flow to the second evaporator 7, but part of the refrigerants from the decompression device 4 flows to a first evaporator 6 through a bypass flow passage 9. At the time of switching from single operation to dual operation, a fixed amount of a refrigerant passes through the solenoid valve 5B and flows to the first evaporator 6. Therefore, this can suppress the generation of the nonuniformity of a temperature of the first evaporator 6 itself and the deterioration of a temperature distribution of air blown out of the first evaporator 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle apparatus and a vehicle air conditioner.

  Conventionally, a vehicle air conditioner includes a compressor that compresses a refrigerant, a cooler that cools the refrigerant from the compressor, and an expansion device that depressurizes the refrigerant that flows out of the cooler. First and second evaporators that evaporate the refrigerant are connected in series, and a bypass flow path that bypasses the second evaporator on the upstream side and flows the refrigerant to the refrigerant inlet side of the first evaporator on the downstream side Some have a three-way valve that adjusts the distribution amount of refrigerant supplied to the second evaporator and the bypass flow path (see, for example, Patent Document 1).

  In this, the 1st air conditioning unit is comprised by the 1st evaporator and the 1st blower ventilating with respect to this 1st evaporator, and it sends air to the 2nd evaporator and this 2nd evaporator. A second air conditioning unit is configured by the second blower.

  Here, the dual operation in which both the first and second air conditioning units function by flowing the refrigerant through the first and second evaporators, and the first air conditioning by flowing the refrigerant through only the first evaporator. One of the single operation that only functions the unit is performed.

Patent document 2 is disclosing the decompressor which can be applied to this kind of apparatus.
JP-A-2005-106318 JP 2000-81157 A

  When the bypass flow path is closed by the three-way valve during dual operation, the same amount of refrigerant flows through each of the first and second evaporators. For this reason, the refrigerant | coolant more than necessary will flow into the 2nd evaporator of an upstream side among 1st, 2nd evaporators, when exhibiting refrigerating capacity. Thereby, a pressure loss becomes high and causes the fall of the efficiency (COP) of a refrigerating cycle.

  Further, when switching from single operation to dual operation, if the bypass flow path is fully closed by the three-way valve and at the same time the refrigerant inlet of the upstream second evaporator is fully opened, the downstream side Sufficient refrigerant will not flow to produce cooling capacity in one evaporator. For this reason, the temperature unevenness of the first evaporator on the downstream side is increased, and the temperature distribution of the air blown out from the first evaporator on the downstream side is deteriorated.

  In view of the above points, the present invention reduces the pressure loss of the upstream evaporator and suppresses the occurrence of temperature unevenness in the downstream evaporator itself when switching from single operation to dual operation. An object is to provide a device and a vehicle air conditioner.

  In order to achieve the above object, in the present invention, a compressor (1) that sucks, compresses, and discharges refrigerant, a cooler (2) that cools refrigerant discharged from the compressor, and the cooler A decompressor (4) for decompressing the refrigerant flowing out, a plurality of evaporators (6, 7) arranged in series in a refrigeration cycle including the compressor and evaporating the refrigerant decompressed by the decompressor, A bypass flow path (9) that bypasses the refrigerant flow upstream evaporator of the plurality of evaporators and flows to the refrigerant inlet side of the downstream evaporator disposed downstream of the upstream evaporator; At the time of single operation which is arranged between the decompressor and the upstream evaporator and stops the operation of the upstream evaporator and operates the downstream evaporator, the decompressor and the upstream evaporator Closed between the upstream evaporator and the downstream evaporator And the first valve (5A) that opens between the decompressor and the upstream evaporator, and the flow restrictor that restricts the flow rate of the refrigerant that flows through the bypass flow path during the dual operation. The first feature is that it comprises a throttle means (5B, 5C) for providing a state.

  Therefore, in the dual operation, the refrigerant can flow to the downstream evaporator by the throttle means. Therefore, the refrigerant is supplied to the downstream evaporator when switching from the single operation to the dual operation while reducing the pressure loss of the upstream evaporator. Therefore, it is possible to suppress the occurrence of temperature unevenness in the downstream evaporator itself.

  In the present invention, the throttling means (5B) is a second valve (5B) that provides a fully-open state that fully opens the bypass flow path and the flow-rate throttling state. During the single operation, the second valve is The second feature is to provide the fully opened state.

Thereby, since sufficient refrigerant | coolant amount can be flowed to a downstream evaporator through a bypass flow path, sufficient refrigerating capacity can be ensured in a downstream evaporator.
Moreover, you may use the 2nd valve (5B, 5C) which provides the said flow volume throttling state as the said throttle means (5B, 5C) at the time of the said single operation.

  In the present invention, when switching from the dual operation to the single operation, the first valve (5A) and the upstream side after the predetermined period after the second valve (5B) is fully opened. The third feature is to close the space between the evaporator and the evaporator.

  As a result, the first valve is closed after preparing a state in which sufficient refrigerant can flow into the downstream evaporator through the bypass flow path, so that the downstream evaporator is sufficiently cooled immediately after switching to single operation. It can be demonstrated. In addition, it is possible to close the first valve after sufficient refrigerant flows into the downstream evaporator through the bypass flow path.

  In the present invention, when switching from the single operation to the dual operation, the second valve is opened after a predetermined period has elapsed since the first valve (5A) has opened the space between the decompressor and the upstream evaporator. A fourth characteristic is that the valve (5B) is brought into the flow restricting state.

  Thereby, since the state which can supply a refrigerant | coolant to a downstream evaporator through a 2nd valve is obtained immediately after it opens a 1st valve, the refrigerant | coolant amount which flows into a downstream evaporator temporarily Since it can suppress that it reduces, generation | occurrence | production of the temperature nonuniformity of a downstream evaporator can be suppressed.

  In the present invention, the throttle means (5B) is a second valve (5B) that provides a fully closed state in which the bypass flow path is fully closed and the flow rate throttle state, and during the dual operation, A second feature of the second valve (5B) is that it provides the fully closed state and the flow rate throttle state, respectively.

  Specifically, in the present invention, determination means (S160) for determining whether or not the degree of superheat of the upstream evaporator is equal to or greater than a predetermined value, and the degree of superheat of the upstream evaporator during the dual operation. When the determination means determines that it is determined to be greater than or equal to a predetermined value, the second valve is fully closed, and the determination means determines that the degree of superheat of the upstream evaporator is less than a predetermined value. And a first control means (S161, 162) for bringing the second valve into the flow-throttle state when it is performed.

  Thereby, it can adjust so that the superheat degree of an upstream evaporator may become less than predetermined value.

  For example, the present invention includes an outside air temperature detecting means (14) for detecting the outside air temperature, and the degree of superheat of the upstream evaporator is less than a predetermined value when the outside air temperature detected by the outside air temperature detecting means is equal to or higher than a predetermined temperature. The determination means may determine that there is, and the determination means may determine that the degree of superheat of the upstream evaporator is equal to or greater than a predetermined value when the outside air temperature detected by the outside air temperature detection means is less than a predetermined temperature.

  For example, the present invention includes an upstream blower (7a) that blows air toward the upstream evaporator, and the degree of superheat of the upstream evaporator is less than a predetermined value when the amount of air blown from the upstream blower is less than a threshold value. The determination means may determine that there is, and the determination means may determine that the degree of superheat of the upstream evaporator is equal to or greater than a predetermined value when the air flow rate of the upstream blower is equal to or greater than a threshold value.

  In this invention, it is 7th that it is provided with the downstream air blower (6a) which ventilates toward the said downstream evaporator, and the said threshold value used for the determination of the said determination means is set to the ventilation volume of the said downstream air blower. It is characterized by.

  Thereby, since the threshold value used for determination by the determination unit can be changed by the air flow rate of the downstream fan, whether or not the degree of superheat of the upstream evaporator is less than a predetermined value corresponding to the air flow rate of the downstream fan. Can be determined satisfactorily.

  In the present invention, the throttle means includes a three-way branch pipe (30) for diverting the refrigerant on the outlet side of the decompressor to the refrigerant inlet side of the upstream evaporator and the refrigerant inlet side of the bypass flow path. Is characterized in that it is provided in the three-way branch pipe.

Thereby, it is possible to realize the diaphragm means without increasing the number of parts.
The ninth feature of the present invention is that the three-way branch pipe is provided in a block material formed in a block shape.

  Thereby, in the three-way branch pipe, even if the refrigerant pressure is high, the strength can be increased so that the refrigerant does not leak.

  In the present invention, it is desirable that the throttle means (5B, 5C) throttle the flow rate of the refrigerant flowing through the bypass channel to a predetermined amount by the refrigerant throttle channel having a diameter of 1 mm to 2.5 mm. In the present invention, the orifice means (5C) may use an orifice tube.

  In the present invention, the high pressure detecting means (15) for detecting the high pressure of the refrigerant between the refrigerant discharge port of the compressor and the refrigerant inlet of the decompressor, and the detected pressure of the high pressure detecting means is a first pressure value. When the pressure is less than, the first valve closes the pressure reducer and the upstream evaporator, and when the detected pressure of the high pressure detecting means is equal to or higher than a first pressure value, the first valve reduces the pressure reducer. And a second control means (S120, S130, S140) for opening a space between the first evaporator and the upstream evaporator.

  Thereby, the high pressure of the refrigerant between the refrigerant discharge port of the compressor and the refrigerant inlet of the decompressor can be adjusted to be lower than the first pressure value by opening and closing the first valve.

  In the present invention, the compressor is operated when the detected pressure of the high pressure detecting means is less than a second pressure value, and the compression is performed when the detected pressure of the high pressure detecting means is greater than or equal to the second pressure value. An eleventh feature is that third control means (S90, S91) for stopping the machine is provided, and the second pressure value is set to a value equal to or higher than the first pressure value.

  Thereby, when the high pressure becomes higher than the second pressure value, the compressor is stopped, so that the refrigerant pressure can be prevented from rising abnormally.

  The twelfth feature of the present invention is that, during the single operation, the first valve opens the decompressor and the upstream evaporator at predetermined intervals.

  As a result, even if refrigerant oil accumulates in the vicinity of the first valve, the refrigerant can be allowed to pass through the first valve every predetermined period, so that the accumulated refrigerant oil can be pushed to the downstream evaporator side. .

  In addition, the code | symbol in the bracket | parenthesis of each means described in a claim and this column shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
FIG. 1 is a configuration diagram of a refrigeration cycle for vehicle air conditioning showing a first embodiment of the present invention. This refrigeration cycle uses CO2 (carbon dioxide) as a refrigerant whose high pressure is equal to or higher than a critical pressure (supercritical state). Used. Therefore, this refrigeration cycle constitutes a supercritical refrigeration cycle.

  The compressor (compressor) 1 obtains driving force from a vehicle travel engine (not shown) via an electromagnetic clutch (not shown) and sucks and compresses the refrigerant. In addition, as the compressor 1, a variable displacement compressor configured to be able to vary the suction capacity is used.

  A cooler 2 serving as an outdoor unit is provided on the discharge side of the compressor 1. The cooler 2 cools the refrigerant by exchanging heat between the discharged refrigerant in the supercritical state at high temperature and high pressure discharged from the compressor 1 and the outside air (outdoor air). Outside air is blown to the cooler 2 by an electric cooling fan (not shown).

  On the outlet side of the cooler 2, a high-pressure side refrigerant flow path 3 a of the internal heat exchanger 3 is provided. Here, the internal heat exchanger 3 performs heat exchange between the high-temperature high-pressure refrigerant in the high-pressure side refrigerant flow path 3a and the low-temperature low-pressure refrigerant in the low-pressure side refrigerant flow path 3b.

  By this heat exchange, the enthalpy of the refrigerant flowing into the first evaporator 6 and the second evaporator 7 to be described later is reduced, and the entire inlet including both the first evaporator 6 and the second evaporator 7 The enthalpy difference (refrigeration capacity) between the refrigerant and the outlet can be increased, and the cycle operation efficiency (COP) can be improved.

  A decompressor 4 serving as a pressure control valve for controlling the high pressure is provided on the outlet side of the high pressure side refrigerant flow path 3a of the internal heat exchanger 3. The opening of the decompressor 4 is adjusted by a mechanical mechanism as control means so that the high pressure of the cycle becomes the target high pressure.

  The decompressor 4 has a temperature sensing part 4a provided between the outlet side of the cooler 2 and the inlet side of the high-pressure side refrigerant flow path 3a of the internal heat exchanger 3, and the inside of the temperature sensing part 4a. Thus, a pressure corresponding to the temperature of the high-pressure refrigerant on the outlet side of the cooler 2 is generated.

  Here, the throttle opening (valve) of the decompressor 4 is balanced by the balance between the internal internal pressure of the temperature sensing portion 4a and the high pressure (specifically, the outlet side refrigerant pressure of the high pressure side refrigerant flow path 3a of the internal heat exchanger 3). By adjusting the body opening degree, the high pressure is adjusted to a target high pressure determined by the high-pressure refrigerant temperature on the outlet side of the cooler 2.

  A first evaporator 6 and a second evaporator 7 are provided on the outlet side of the decompressor 4. The first evaporator 6 and the second evaporator 7 are connected so as to be arranged in series with respect to the refrigerant flow of the refrigeration cycle including the compressor 1. When the two evaporators are connected in series, the second evaporator 7 is arranged on the upstream side of the refrigerant flow with respect to the first evaporator 6, and the first evaporator 6 is more than the second evaporator 7. It arrange | positions in the downstream of a refrigerant | coolant flow.

  Here, the 1st evaporator 6 is arrange | positioned in the air conditioning casing which forms the air path of the front seat side air conditioning unit 6c of a vehicle air conditioner. The first evaporator 6 is blown with blown air from the first electric blower 6a, and the first evaporator 6 constitutes air cooling means for cooling the blown air from the first electric blower 6a by evaporation of the refrigerant. . The state where the operation of the first evaporator 6 is stopped is obtained by stopping the air blowing to the first evaporator 6.

  The 2nd evaporator 7 is arrange | positioned in the air conditioning casing which forms the air path of the rear seat side air conditioning unit 7c of a vehicle air conditioner. The second evaporator 7 is blown with blown air from the second electric blower 7a, and the second evaporator 7 has air cooling means for cooling the blown air from the second electric blower 7a by evaporation of the refrigerant. Constitute. The state where the operation of the first evaporator 6 is stopped is obtained by stopping the air blowing to the first evaporator 6.

  Further, a bypass passage 9 is provided on the outlet side of the decompressor 4 to bypass the second evaporator 7 and flow the refrigerant to the refrigerant inlet side of the first evaporator 6. That is, the bypass flow path 9 is a refrigerant passage that bypasses the second evaporator 7 and flows the refrigerant from the refrigerant inlet side of the second evaporator 7 to the refrigerant outlet side of the second evaporator 7.

  An electromagnetic valve 5A as a first valve is provided upstream of the second evaporator 7, and the electromagnetic valve 5A is fully opened between the refrigerant outlet of the decompressor 4 and the refrigerant inlet of the second evaporator 7. Or fully close.

  The electromagnetic valve 5A provides a fully open state and a fully closed state by switching between two states such as a fully open state and a fully closed state. The electromagnetic valve 5A may provide a fully open state and a fully closed state by a valve that can be adjusted from fully closed to fully open.

  The bypass flow path 9 is provided with a solenoid valve 5B as a second valve. The solenoid valve 5B is in a fully open state in which the bypass flow path 9 is fully opened in the open state, and in the closed state, the bypass flow path 9 is in the open state. 9 is in a fixed throttle state (that is, a flow rate throttle state) in which the amount of refrigerant flowing to 9 is throttled to a predetermined amount (that is, a constant amount). That is, the solenoid valve 5B provides a fully open state and a fixed throttle state by switching between two states, a fully open state and a fixed throttle state.

  The solenoid valve 5B may provide a fully open state and a fully closed state by a valve that can be adjusted from a fully closed state to a fully open state including a fully open state and a fixed throttle state. The electromagnetic valve 5B constitutes a throttle means described in the claims by being in a fixed throttle state.

  An accumulator 8 is provided on the outlet side of the first evaporator 6. This accumulator 8 is a gas-liquid separating means for separating the liquid refrigerant and gas refrigerant of the outlet refrigerant of the first evaporator 6 and storing excess refrigerant in the cycle, and the outlet side of the accumulator 8 is the internal heat exchanger 3. Is connected to the inlet side of the low-pressure side refrigerant flow path 3b. The outlet side of the low-pressure side refrigerant flow path 3 b of the internal heat exchanger 3 is connected to the suction side of the compressor 1.

  The air conditioner ECU (electronic control unit) 10 includes a timer, a memory, a microcomputer, and the like, and controls the electric blowers 6a and 7a and the electromagnetic valves 5A and 5B based on detection values of various sensors.

  The various sensors include an outside air temperature sensor 14 that detects the temperature TAM outside the passenger compartment, a high pressure sensor 15 that detects the discharge refrigerant pressure Ph on the refrigerant discharge port side of the compressor 1, and a pressure sensor 16 that detects the suction pressure of the compressor 1. It comprises a temperature sensor 17 for detecting the refrigerant temperature inside the second evaporator 7.

  The air volume setting switch (BSW) 11 sets the air volume of the electric blowers 6a and 7a. A compressor start switch (ACSW) 12 is a switch for instructing start of the compressor 1. The operation changeover switch 13 is a switch for setting one of dual operation and single operation described later.

  Next, the basic operation in the above configuration will be described. When the compressor 1 is rotationally driven by the driving force of the vehicle engine, the high-temperature and high-pressure refrigerant (CO2) compressed by the compressor 1 flows into the cooler 2 in a supercritical state where the pressure is equal to or higher than the critical pressure. Here, the high-temperature and high-pressure supercritical refrigerant exchanges heat with the outside air to dissipate heat into the outside air, thereby reducing enthalpy.

  The high-pressure refrigerant at the outlet of the cooler 2 flows into the high-pressure side passage 3a of the internal heat exchanger 3, and exchanges heat with the low-temperature low-pressure refrigerant (outlet-side refrigerant of the accumulator 8) passing through the low-pressure side passage 3b. Since it is cooled, enthalpy is further reduced. The high-pressure refrigerant that has passed through the high-pressure side passage 3 a of the internal heat exchanger 3 is decompressed by the decompressor 4.

  Here, since the operation of the first and second evaporators 6 and 7 varies depending on the operation state associated with the opening and closing of the electromagnetic valves 5A and 5B, the following description will be divided into dual operation and single operation with reference to FIG. To do.

(Single operation)
In the air conditioner ECU 10, as shown in FIG. 2, the electromagnetic valve 5A fully closes the flow path between the refrigerant outlet side of the decompressor 4 and the refrigerant inlet side of the second evaporator 7, and the electromagnetic valve 5B is a bypass flow path. Each solenoid valve is controlled so that 9 is fully opened.

  Accordingly, the refrigerant that has passed through the bypass flow path 9 flows into the first evaporator 6, and the refrigerant absorbs heat from the blown air of the first electric blower 6 a and evaporates. Thereby, blowing air is cooled and the cold wind blows off to the vehicle interior front seat side.

  Thereafter, the refrigerant that has passed through the first evaporator 6 is separated into liquid refrigerant and gas refrigerant by the accumulator 8, and only the gas refrigerant passes through the low-pressure side refrigerant flow path 3 b of the internal heat exchanger 3 and is sucked into the compressor 1. Sucked into the side.

  In addition, as shown in FIG. 2, the air conditioner ECU 10 fully opens the electromagnetic valve 5A every predetermined period (for example, two hours). Along with this, the refrigerant from the decompressor 4 flows into the second evaporator 7. As a result, the lubricant flowing in from the decompressor 4 pushes the lubricating oil that has accumulated in the second evaporator 7 to the refrigerant inlet side of the first evaporator 6.

(Dual operation)
In the air conditioner ECU 10, as shown in FIG. 2, the electromagnetic valve 5A fully opens the flow path between the refrigerant outlet side of the decompressor 4 and the refrigerant inlet side of the second evaporator 7, and the electromagnetic valve 5B is in a fixed throttle state. Each solenoid valve is controlled so that

  The refrigerant that has passed through the decompressor 4 flows into the second evaporator 7, and the refrigerant absorbs heat from the blown air of the second electric blower 7 a and evaporates. Thus, the blown air is cooled, and the cold air is blown out to the rear seat side of the vehicle interior.

  On the other hand, a predetermined amount of refrigerant that has passed through the electromagnetic valve 5B flows into the first evaporator 6 from the bypass flow path 9. For this reason, in addition to the refrigerant that has passed through the second evaporator 7, the refrigerant that has passed through the electromagnetic valve 5 </ b> B and the bypass channel 9 flows into the first evaporator 6. Accordingly, in the first evaporator 6, the refrigerant absorbs heat from the blown air of the first electric blower 6a and evaporates. Thereby, the blowing air of the 1st electric blower 6a is cooled, and the cold wind blows off to the vehicle interior front seat side.

  Thereafter, the refrigerant that has passed through the first evaporator 6 is separated into liquid refrigerant and gas refrigerant by the accumulator 8, and only the gas refrigerant passes through the low-pressure side refrigerant flow path 3 b of the internal heat exchanger 3 and is sucked into the compressor 1. Inhaled into the mouth.

  According to the present embodiment described above, during dual operation, the air conditioner ECU 10 fully opens the electromagnetic valve 5A and places the electromagnetic valve 5B in a fixed throttle state. For this reason, not all of the refrigerant flowing out from the decompressor 4 flows to the second evaporator 7, but a part of the refrigerant from the decompressor 4 flows to the first evaporator 6 through the bypass channel 9. Therefore, since the amount of refrigerant flowing through the second evaporator 7 can be reduced, the pressure loss generated in the second evaporator 7 can be suppressed.

  In addition, since the electromagnetic valve 5B is in a fixed throttle state during dual operation, a predetermined amount of refrigerant passes through the electromagnetic valve 5B and flows directly into the first evaporator 6 when switching from single operation to dual operation. Therefore, the occurrence of temperature unevenness in the first evaporator 6 itself is suppressed, and the deterioration of the air temperature distribution blown out from the first evaporator 6 is suppressed.

  In the present embodiment, the electromagnetic valve 5B fully opens the bypass flow path 9 at the time of single operation. Therefore, sufficient refrigerant that has passed through the electromagnetic valve 5B and the bypass flow path 9 flows into the first evaporator 6. Sufficient cooling capacity can be secured in the first evaporator 6.

  Here, FIG. 3 shows the result (comparative example) of measuring the blown air temperature of the first evaporator 6 when a three-way valve that only switches the passage is used instead of the electromagnetic valves 5A and 5B, and FIG. The result of having measured the blowing air temperature of the 1st evaporator 6 of an embodiment is shown. 3 and 4, the vertical axis represents the temperature of the blown air from the first evaporator 6, and the horizontal axis represents time.

  As can be seen from FIGS. 3 and 4, in the comparative example, when the dual operation is started, the temperature of the blown air from the first evaporator 6 is temporarily increased rapidly. However, in the present embodiment, the dual operation is started even if the dual operation is started. The blown air temperature of one evaporator 6 is in a flat state where a substantially constant temperature is maintained without rapidly increasing.

  In addition, even when the solenoid valve 5A is closed during single operation, if the airtightness of the solenoid valve 5A is low, refrigerant may pass through the solenoid valve 5A and accumulate in the vicinity of the solenoid valve 5A. In this case, when the refrigerant evaporates, only the lubricating oil contained in the refrigerant accumulates in the vicinity of the electromagnetic valve 5A.

  In contrast, in the present embodiment, the air conditioner ECU 10 fully opens the electromagnetic valve 5A every predetermined period (for example, two hours). Accordingly, the lubricating oil in which the refrigerant from the decompressor 4 stays in the vicinity of the second evaporator 7 is pushed away to the refrigerant inlet side of the first evaporator 6. Along with this, it is possible to secure the amount of lubricating oil that returns to the compressor 1 side.

  In addition, when the solenoid valve 5B is set to a fixed throttle state during single operation, the refrigerant discharge pressure is likely to increase to an abnormal pressure when the rotation speed of the compressor 1 increases as the rotation speed of the vehicle running engine increases.

  On the other hand, in this embodiment, the bypass flow path 9 is fully opened by the electromagnetic valve 5B during single operation. Thereby, even if the rotation speed of the compressor 1 rises, it becomes difficult for the refrigerant discharge pressure to rise to an abnormal pressure.

  Next, the diameter of the refrigerant throttle channel of the solenoid valve 5B when the solenoid valve 5B is in the fixed throttle state in the present embodiment (hereinafter referred to as a fixed throttle diameter) will be described.

  In the present embodiment, the fixed throttle diameter needs to be a diameter at which a sufficient amount of refrigerant flows through the second evaporator 7 under “conditions that require the most refrigerant in the second evaporator 7” during dual operation.

  The “condition that the second evaporator 7 requires the most amount of refrigerant” is a case where the air volume of the first electric blower 6a is the minimum value (Lo) and the air volume of the second electric blower 7a is the maximum value (Hi). . FIG. 5 shows the result of examining the correlation between the fixed throttle diameter and the degree of superheat (superheat) of the second evaporator 7 under the airflow conditions of the first and second electric blowers 6a and 7a.

The vertical axis in FIG. 5 indicates the degree of superheat of the second evaporator 7, the horizontal axis indicates time, and the plot (black square) indicates that the compressor 1 (vehicle engine) has a high rotational speed and a high air conditioning load ( This shows a case where the air temperature blown out to the second evaporator 7 is high and the humidity is high, the air temperature blown out to the cooler 2 is also high, and the amount of air blown is small.
The plot (black rhombus) shows that the compressor 1 (vehicle driving engine) has a low rotation speed and a high air conditioning load (the air temperature blown to the second evaporator 7 is high and the humidity is high, and the blower blows to the cooler 2). In this case, the air temperature is high and the air flow rate is low.

  The plot (black triangle) shows that the compressor 1 (vehicle engine) has a high rotation speed and a low air conditioning load (the air temperature blown to the second evaporator 7 is high and the humidity is high, and the blower blows to the cooler 2). In this case, the air temperature is high and the air flow rate is low.

  According to the plots shown in FIG. 5 above, if the superheat degree SH of the second evaporator 7 is allowed up to 10 ° C., the diameter of the fixed throttle is 1.9 mm, and if the superheat degree is not allowed, the air conditioning load is 1.5 mm. When the superheat degree SH when the air conditioning load is high and the superheat degree SH when the air conditioning load is high is set to 15 ° C., the fixed throttle diameter is 2.2 mm. As described above, it is desirable that the fixed throttle diameter is 1.0 mm to 2.5 mm. More desirably, the fixed throttle diameter should be 1.5 mm to 2.2 mm.

(Second Embodiment)
In the first embodiment described above, the example in which the solenoid valve 5B is in the fixed throttle state in which the amount of refrigerant flowing in the bypass flow path 9 in the closed state is reduced to a predetermined amount has been described. In the second embodiment, as shown in FIG. 6, the solenoid valve 5 </ b> B is in a fixed throttle state in which the amount of refrigerant flowing through the bypass flow path 9 in a valve-open state is reduced to a predetermined amount, and is fully closed in a valve-closed state. The solenoid valve 5B provides a fully closed state and a fixed throttle state by switching between two states, a fully closed state and a fixed throttle state.

  In the present embodiment, a high-pressure sensor 15 (see FIG. 1) is used as a high-pressure detection unit that detects the refrigerant discharge pressure (that is, high-pressure pressure) on the refrigerant discharge port side of the compressor 1. In the refrigeration cycle, the high-pressure sensor 15 detects the pressure at any location as long as it is from the refrigerant outlet side of the compressor 1 to the refrigerant inlet side of the decompressor 4 as well as the refrigerant outlet side of the compressor 1. Also good.

  The operation of this embodiment will be described with reference to FIGS. FIG. 7 is a chart showing the states of the solenoid valves 5A and 5B in the single operation and the dual operation in the present embodiment. FIG. 8 is a flowchart showing control processing of the electromagnetic valves 5A and 5B.

  The air conditioner ECU 10 executes the computer program according to the flowchart of FIG. The execution of the computer program is performed when the setting of the air volume is changed by the air volume setting switch 11 or when the start of the compressor 1 is instructed by the compressor start switch 12.

  First, in step S90, it is determined whether or not the detected pressure value Pd of the high pressure sensor is equal to or higher than the high pressure limit value Hg. Here, when the detected pressure value Pd of the high pressure sensor is equal to or higher than the high pressure limit value Hg, the compressor 1 is urgently stopped as YES (step S91). The high pressure limit value Hg corresponds to the second pressure value in the claims. When the detected pressure value Pd of the high pressure sensor is less than the high pressure limit value Hg, NO is determined and the process proceeds to step S100.

  Here, based on the output signal of the operation changeover switch 13, it is determined which of the dual operation and the single operation is set.

  When the single operation is set by the operation changeover switch 13, the process proceeds to step S110 to open the electromagnetic valve 5B. As a result, the electromagnetic valve 5B enters a fixed throttle state, and accordingly, the refrigerant that has passed through the bypass flow path 9 and the electromagnetic valve 5B flows into the first evaporator 6.

  Next, in step S120, the electromagnetic valve 5A is fully closed. Thereafter, in step S130, it is determined whether or not the detected pressure value Pd of the high pressure sensor 15 is equal to or higher than the high pressure threshold Hs. Here, the high pressure threshold value Hs of the present embodiment corresponds to the first pressure value in the claims and is set to a value less than the high pressure limit value Hg.

  In step S130, when the detected pressure value Pd of the high pressure sensor 15 is less than the high pressure threshold Hs, it is determined as NO and the process returns to step S120. On the other hand, when the detected pressure value Pd of the high-pressure sensor 15 is equal to or higher than the high-pressure threshold Hs, it is determined as YES, the process proceeds to step S140, and the electromagnetic valve 5A is fully opened. Thereby, in the refrigeration cycle, it is possible to prevent the refrigerant pressure on the high pressure side between the refrigerant discharge port side of the compressor 1 and the refrigerant inlet side of the decompressor 4 from rising rapidly to an abnormally high pressure.

  On the other hand, when it is determined in step S100 that the dual operation is set, the electromagnetic valve 5A is fully opened. Thereafter, in step S160, it is determined based on the amount of air blown by the second electric blower 7a whether or not the second evaporator 7 has a degree of superheat above a predetermined value.

  Specifically, it is determined whether or not the air volume of the second electric blower 7a is equal to or greater than the air volume threshold. In the present embodiment, the air volume of the first electric blower 6a is used as the air volume threshold. Note that, as the air volume threshold, a predetermined constant value other than the air volume of the first electric blower 6a may be used.

  When the air volume of the second electric blower 7a is equal to or greater than the air volume threshold value, it is determined as YES that the second evaporator 7 has a degree of superheat greater than a predetermined value. That is, it is determined that a sufficient amount of refrigerant does not flow into the second evaporator 7. In this case, the process proceeds to step S161, and the electromagnetic valve 5B is fully closed. Accordingly, the amount of refrigerant that passes through the electromagnetic valve 5A and flows into the second evaporator 7 can be increased.

  Moreover, when the air volume of the 2nd electric blower 7a is less than an air volume threshold value in step S160, it determines with NO being the superheat degree of the 2nd evaporator 7 being less than predetermined value. That is, it is determined that a sufficient amount of refrigerant is flowing into the second evaporator 7. Therefore, the electromagnetic valve 5B is opened (that is, in a fixed throttle state). Therefore, the refrigerant from the decompressor 4 flows to the first evaporator 6 through the bypass passage 9 via the electromagnetic valve 5B.

  In this way, it is determined whether or not the second evaporator 7 has a degree of superheat above a predetermined value, and the electromagnetic valve 5B is opened and closed based on this determination.

  According to the present embodiment described above, when dual operation is performed, the second evaporator 7 does not have a degree of superheat above a predetermined value, and a sufficient amount of refrigerant flows into the second evaporator 7. When the determination is made, the electromagnetic valve 5B is opened (fixed throttle state). For this reason, during dual operation, as in the first embodiment described above, not all of the refrigerant that has flowed out of the pressure reducer 4 flows to the second evaporator 7, but a portion of the refrigerant from the pressure reducer 4 It flows to the first evaporator 6 through the bypass channel 9. Therefore, since the amount of refrigerant flowing through the second evaporator 7 can be reduced, the pressure loss generated in the second evaporator 7 can be suppressed.

  In addition, since the electromagnetic valve 5B is in a fixed throttle state (opened state) during dual operation, a predetermined amount of refrigerant passes through the electromagnetic valve 5B and passes through the first evaporator 6 when switching from single operation to dual operation. Flow into. Therefore, similarly to the above-described first embodiment, the occurrence of temperature unevenness in the first evaporator 6 is suppressed, and the deterioration of the temperature distribution of the air blown out from the first evaporator 6 is suppressed.

  Furthermore, in this embodiment, when it is determined that the degree of superheat of the second evaporator 7 is less than a predetermined value, the electromagnetic valve 5B is opened, but the second evaporator 7 is overheated by a predetermined value or more. When it is determined that the degree has occurred, the electromagnetic valve 5B is fully closed.

  Therefore, when it is determined that the second evaporator 7 has a degree of superheat of a predetermined value or more, the second amount of refrigerant flowing through the electromagnetic valve 5A and flowing into the second evaporator 7 is increased. The degree of superheat of the evaporator 7 can be adjusted to be less than a predetermined value. Thereby, it can suppress that the cooling effect | action of the 2nd evaporator 7 falls.

  In this embodiment, since the air volume of the first electric blower 6a is used as the air volume threshold, the degree of superheat can be determined corresponding to the air volume of the first electric fan 6a.

In the second embodiment described above, it is determined whether or not the second evaporator 7 has a degree of superheat above a predetermined value based on the amount of air blown from the second electric blower 7a. However, the present invention is not limited to this. The following may also be used.
(1) Using the outside air temperature sensor 14 (outside air temperature detecting means) that detects the outside air temperature, it is determined whether or not the outside air temperature TAM is equal to or higher than a predetermined temperature (that is, a constant temperature). When the outside air temperature TAM is equal to or higher than a predetermined temperature, it is determined that the degree of superheat of the second evaporator 7 is less than a predetermined value, and when the outside air temperature TAM is lower than the predetermined temperature, the second evaporator 7 has a predetermined value. It is determined that the degree of superheat exceeding the value occurs.
(2) The degree of superheat of the second evaporator 7 is calculated from the detection value of the pressure sensor 16 and the detection value of the temperature sensor 17, and it is determined whether or not the calculated degree of superheat is a predetermined value or more. The pressure sensor 16 detects the suction pressure of the compressor 1, and the temperature sensor 17 detects the refrigerant temperature inside the second evaporator 7.

(Third embodiment)
In the first and second embodiments described above, the example in which the electromagnetic valve 5B is used for the bypass flow path 9 has been described. Instead, in the third embodiment, as shown in FIG. An orifice tube 5C is used as a throttle means for restricting the flow rate of the refrigerant flowing through 9 to a predetermined amount in the refrigerant throttle channel.

  Here, the orifice tube 5C constitutes a throttling means regardless of single operation or dual operation. The diameter of the refrigerant throttle channel (that is, the fixed throttle diameter) of the orifice tube 5C is desirably 1.0 mm to 2.5 mm, and more desirably 1.5 mm to 2.2 mm. 9, the same reference numerals as those in FIG. 1 denote the same elements, and the description thereof is omitted.

  In the present embodiment, the air conditioner ECU 10 fully closes the electromagnetic valve 5A during single operation, and the air conditioner ECU 10 fully opens the electromagnetic valve 5A during dual operation.

  According to the present embodiment described above, a predetermined amount of refrigerant flows to the first evaporator 6 through the bypass channel 9 and the orifice tube 5C during dual operation. Therefore, as in the first and second embodiments described above, not all of the refrigerant that has flowed out of the pressure reducer 4 flows to the second evaporator 7, but a part of the refrigerant from the pressure reducer 4 is bypassed. It flows through the path 9 to the first evaporator 6. Therefore, since the amount of refrigerant flowing through the second evaporator 7 can be reduced, the pressure loss generated in the second evaporator 7 can be suppressed.

  When switching from single operation to dual operation, a predetermined amount of refrigerant flows into the first evaporator 6 through the orifice tube 5C. Therefore, similarly to the first and second embodiments described above, the occurrence of temperature unevenness in the first evaporator 6 is suppressed, and the deterioration of the air temperature distribution blown out from the first evaporator 6 is suppressed.

(Other embodiments)
In the first and second embodiments described above, when switching from dual operation to single operation, the decompressor 4 and the solenoid valve 5A are used by the solenoid valve 5A after a predetermined period (that is, a certain period) has elapsed since the solenoid valve 5B is fully opened. The space between the second evaporators 7 may be closed.

  As a result, the electromagnetic valve 5A is closed after preparing a state in which a sufficient amount of refrigerant can flow into the first evaporator 6 through the bypass flow path 9, so that it is sufficient for the first evaporator 6 immediately after switching to the single operation. A cooling effect can be exhibited. In addition, the electromagnetic valve 5A can be closed after a sufficient amount of refrigerant flows into the first evaporator 6 through the bypass flow path 9.

  In the first and second embodiments described above, when switching from single operation to dual operation, the electromagnetic valve 5A is opened while the electromagnetic valve 5B is fully open, and then a predetermined period (that is, a certain period) is set. After elapses, the electromagnetic valve 5B may be in a fixed throttle state.

 Thereby, since the state which can supply a refrigerant | coolant to the 1st evaporator 6 through the electromagnetic valve 5B of a full open state is obtained immediately after the solenoid valve 5A opens, the refrigerant | coolant which flows into the 1st evaporator 6 is obtained. Since the amount can be suppressed from temporarily decreasing, the occurrence of temperature unevenness in the first evaporator 6 can be suppressed.

  In the above-described third embodiment, the example in which the orifice tube 5C that provides a fixed throttle state that throttles the amount of refrigerant flowing through the bypass flow path 9 to a predetermined amount has been described as the throttle means. On the other hand, an electromagnetic valve 5C having a function of adjusting the valve opening may be used as the throttle means.

  Specifically, the adjustment function of the valve opening degree of the electromagnetic valve 5C is to switch between two states, a fully open state in which the bypass passage 9 is fully opened and a fully closed state in which the bypass passage 9 is fully closed. Providing a fully open state and a fully closed state.

When the electromagnetic valve 5C configured as described above is used in the third embodiment described above, the following (1) and (2) may be used.
(1) When switching from dual operation to single operation, the solenoid valve 5A is used to open a gap between the decompressor 4 and the second evaporator 7 after a predetermined period (that is, a certain period) has elapsed since the solenoid valve 5C is fully opened. It may be closed.

As a result, as described above, the electromagnetic valve 5A is closed after preparing a state in which sufficient refrigerant can flow into the first evaporator 6 through the bypass flow path 9, so that the first evaporator immediately after switching to single operation. 6 can exhibit a sufficient cooling effect. In addition, the electromagnetic valve 5A can be closed after a sufficient amount of refrigerant flows into the first evaporator 6 through the bypass flow path 9.
(2) When switching from the single operation to the dual operation, the solenoid valve 5C is opened after the solenoid valve 5A is opened with the solenoid valve 5C fully opened, and a predetermined period (that is, a predetermined period) has elapsed. It may be in a fixed aperture state.

 Accordingly, as described above, since the state in which the refrigerant can be supplied to the first evaporator 6 through the electromagnetic valve 5C in the fully opened state can be obtained immediately after the electromagnetic valve 5A is opened, the first evaporator Since it is possible to suppress the amount of refrigerant flowing through 6 from being temporarily reduced, it is possible to suppress the occurrence of temperature unevenness in the first evaporator 6.

 In the second and third embodiments described above, the air conditioner ECU 10 opens the solenoid valve 5A every predetermined period (for example, two hours), and the lubricating oil in which the refrigerant from the decompressor 4 stays in the vicinity of the second evaporator 7. May be pushed to the refrigerant inlet side of the first evaporator 6 at predetermined intervals. Along with this, it is possible to secure the amount of lubricating oil that returns to the compressor 1 side.

  In the third embodiment described above, the example in which the orifice tube 5C is used as the throttle means has been described, but instead of this, the throttle means may be provided in the three-way branch pipe.

  That is, the outlet side of the decompressor 4 is connected to the refrigerant inlet side of the three-way branch pipe, the first refrigerant outlet is connected to the refrigerant inlet of the bypass passage 9, and the second refrigerant outlet is the refrigerant inlet of the second evaporator 7. Connect to. Here, a fixed throttle portion is provided on the first refrigerant outlet side of the three-way branch pipe so that the flow rate of the refrigerant flowing into the bypass passage 9 is limited to a predetermined amount (that is, a constant amount). Thereby, it is possible to realize the diaphragm means without increasing the number of parts.

  Moreover, you may make it comprise a three-way branch piping by the three-way branch block 30 shown in FIG. 10, FIG.

  FIG. 10 is a perspective view of the three-way branch block 30, and FIG. 11 is a perspective view showing the inside of the three-way branch block 30.

The three-way branch block 30 has a metal block member 30a provided with a refrigerant inlet 31 and first and second refrigerant outlets 32 and 33. By using the metal block member 30a, the refrigerant pressure is high. However, the strength can be increased so that the refrigerant does not leak.
Here, the three-way branch block 30 includes a flow path 34 that communicates between the refrigerant inlet 31 and the second refrigerant outlet 33, and a flow path 35 that communicates between the flow path 34 and the first refrigerant outlet 32. The flow path 35 is provided with a throttle portion 35a that restricts the amount of refrigerant flowing from the flow path 34 to the first refrigerant outlet 32 to a predetermined amount (that is, a constant amount).

  In the above-described first to third embodiments, the example using two evaporators has been described, but three or more evaporators may be used instead.

  In the second embodiment described above, it is determined whether the detected pressure value Pd of the high pressure sensor 15 is equal to or higher than the high pressure threshold Hs (step S130 in FIG. 8), and the electromagnetic valve 5A is opened and closed based on this determination (in FIG. 8). In the first and third embodiments described above, similarly, it is determined whether or not the detected pressure value Pd of the high pressure sensor 15 is equal to or higher than the high pressure threshold Hs. A control process for opening and closing the electromagnetic valve 5A may be added based on the determination.

  In the second embodiment described above, it is determined whether or not the detected pressure value Pd of the high pressure sensor is equal to or higher than the high pressure limit value Hg (step S90), and the compressor 1 is urgently stopped based on this determination (step S91). Although the example has been described, in the first and third embodiments described above, similarly, it is determined whether or not the detected pressure value Pd of the high pressure sensor is equal to or higher than the high pressure limit value Hg, and based on this determination, the compressor Control processing for emergency stop of 1 may be added.

In the first to third embodiments described above, the example in which the refrigeration cycle apparatus is applied to a vehicle air conditioner has been described. However, instead of this, it may be applied to an installation type refrigeration apparatus, an installation type air conditioner, or the like.
Hereinafter, the correspondence relationship between the above embodiment and the configuration of the scope of the claims will be described. The second electric blower 7a corresponds to the upstream blower, the first electric blower 6a corresponds to the downstream blower, and S160. Corresponds to the determination means, the control processing of S161 and S162 corresponds to the first control means, the control processing of S120, S130 and S140 corresponds to the second control means, and the control processing of S90 and S91 is the third control. It corresponds to the means.

It is a lineblock diagram of the refrigeration cycle for vehicle air-conditioning which shows a 1st embodiment of the present invention. It is a chart which shows the control processing of the air-conditioner ECU of FIG. It is a graph for demonstrating the effect of the above-mentioned 1st Embodiment. It is a graph for demonstrating the effect of the above-mentioned 1st Embodiment. It is a graph for demonstrating the appropriate value of the fixed aperture diameter of the above-mentioned 1st Embodiment. It is a chart which shows the control processing of air-conditioner ECU of 2nd Embodiment of this invention. It is a chart which shows the control processing of air-conditioner ECU of the above-mentioned 2nd Embodiment. It is a flowchart which shows the control processing of air-conditioner ECU of the above-mentioned 2nd Embodiment. It is a block diagram of the refrigeration cycle for vehicle air conditioning which shows 3rd Embodiment of this invention. It is a perspective view of the three-way branch block of another example. It is a perspective view of the three-way branch block of another example.

Explanation of symbols

1 ... compressor, 3 ... internal heat exchanger, 4 ... decompressor,
5A, 5B ... Solenoid valve, 5C ... Orifice tube, 6, 7 ... Evaporator,
6a, 7a ... electric blower, 9 ... bypass channel, 10 ... air conditioner ECU.

Claims (19)

A compressor (1) for sucking, compressing and discharging refrigerant;
A cooler (2) for cooling the refrigerant discharged from the compressor;
A decompressor (4) for decompressing the refrigerant flowing out of the cooler;
A plurality of evaporators (6, 7) arranged in series in a refrigeration cycle including the compressor and evaporating the refrigerant decompressed by the decompressor;
A bypass flow path (9) that bypasses the refrigerant flow upstream evaporator of the plurality of evaporators and flows to the refrigerant inlet side of the downstream evaporator disposed downstream of the upstream evaporator;
At the time of single operation which is arranged between the decompressor and the upstream evaporator and stops the operation of the upstream evaporator and operates the downstream evaporator, the decompressor and the upstream evaporator A first valve (5A) that opens between the pressure reducer and the upstream evaporator, during dual operation in which the upstream evaporator and the downstream evaporator are operated, respectively,
The refrigeration cycle apparatus according to claim 1, further comprising a throttle means (5B, 5C) that provides a flow throttle state that throttles a refrigerant flow rate flowing through the bypass flow path during the dual operation. The throttle means (5B) is a second valve (5B) that provides a fully open state in which the bypass flow path is fully opened and the flow rate throttle state,
2. The refrigeration cycle apparatus according to claim 1, wherein the second valve provides the fully opened state during the single operation. The refrigeration cycle apparatus according to claim 1, wherein the throttle means (5B, 5C) is a second valve (5B, 5C) that provides the flow rate throttle state during the single operation. The throttle means (5B) is a second valve (5B) that provides a fully closed state in which the bypass flow path is fully closed and the flow rate throttle state,
4. The refrigeration cycle apparatus according to claim 1, wherein during the dual operation, the second valve (5 </ b> B) provides the fully closed state and the flow rate throttle state, respectively. 5. When switching from the dual operation to the single operation, the first valve (5A) causes the decompressor and the upstream evaporator to pass after a predetermined period has elapsed since the second valve (5B) is fully opened. The refrigeration cycle apparatus according to any one of claims 2 to 4, wherein the gap is closed. When switching from the single operation to the dual operation, the second valve (5B) after a predetermined period has elapsed since the first valve (5A) has opened the space between the pressure reducer and the upstream evaporator. The refrigeration cycle apparatus according to any one of claims 2 to 5, wherein the flow rate is reduced. Determination means (S160) for determining whether or not the degree of superheat of the upstream evaporator is equal to or greater than a predetermined value;
During the dual operation, when the determination means determines that the degree of superheat of the upstream evaporator is greater than or equal to a predetermined value, the second valve is fully closed, and the degree of superheat of the upstream evaporator is a predetermined value. 5. A refrigeration cycle according to claim 4, further comprising: first control means (S <b> 161, 162) that brings the second valve into the flow-throttle state when the determination means determines that the value is less than apparatus. An outside air temperature detecting means (14) for detecting the outside air temperature;
When the outside air temperature detected by the outside air temperature detecting means is equal to or higher than a predetermined temperature, the determining means determines that the degree of superheat of the upstream evaporator is less than a predetermined value, and the outside air temperature detected by the outside air temperature detecting means is a predetermined temperature. The refrigeration cycle apparatus according to claim 7, wherein the determination means determines that the degree of superheat of the upstream evaporator is equal to or greater than a predetermined value when the temperature is less than the value. An upstream blower (7a) for blowing air toward the upstream evaporator,
The determination means determines that the degree of superheat of the upstream evaporator is less than a predetermined value when the air flow rate of the upstream fan is less than a threshold value, and the upstream when the air flow rate of the upstream fan is equal to or greater than the threshold value. The refrigeration cycle apparatus according to claim 7, wherein the determination unit determines that the degree of superheat of the side evaporator is equal to or greater than a predetermined value. A downstream blower (6a) for blowing air toward the downstream evaporator,
The refrigeration cycle apparatus according to claim 9, wherein the threshold value used for determination by the determination unit is set to an air flow rate of the downstream fan. 4. The refrigeration cycle apparatus according to claim 1, wherein the throttle means (5C) is an orifice tube. A three-way branch pipe (30) for branching the refrigerant on the outlet side of the decompressor to each of the refrigerant inlet side of the upstream evaporator and the refrigerant inlet side of the bypass flow path;
The refrigeration cycle apparatus according to claim 11, wherein the throttle means is provided in the three-way branch pipe. The refrigeration cycle apparatus according to claim 12, wherein the three-way branch pipe is provided in a block material formed in a block shape. The throttle means (5B, 5C) is configured to restrict the flow rate of the refrigerant flowing through the bypass passage to a predetermined amount by a refrigerant throttle passage having a diameter of 1 mm to 2.5 mm. Thru | or thirteenth refrigeration cycle apparatus. High pressure detection means (15) for detecting a high pressure of the refrigerant between the refrigerant discharge port of the compressor and the refrigerant inlet of the decompressor;
When the detected pressure of the high pressure detecting means is less than a first pressure value, the first valve closes the pressure reducer and the upstream evaporator, and the detected pressure of the high pressure detecting means is the first pressure. 2. A second control means (S <b> 120, S <b> 130, S <b> 140) that opens between the pressure reducer and the upstream evaporator by the first valve when the value is equal to or greater than a value. 14. The refrigeration cycle apparatus according to any one of 14. The compressor is operated when the detected pressure of the high pressure detecting means is less than a second pressure value, and the compressor is stopped when the detected pressure of the high pressure detecting means is greater than or equal to the second pressure value. A third control means (S90, S91),
The refrigeration cycle apparatus according to claim 15, wherein the second pressure value is set to a value equal to or greater than the first pressure value. 17. The method according to claim 1, wherein, during the single operation, the first valve opens the space between the pressure reducer and the upstream evaporator every predetermined period. The refrigeration cycle apparatus described. The refrigeration cycle apparatus according to any one of claims 1 to 17, wherein the refrigerant is carbon dioxide. A vehicle air conditioner comprising the refrigeration cycle apparatus according to one of claims 1 to 18 for air conditioning a vehicle interior,
A rear-seat air conditioning unit (7c) that includes the upstream-side evaporator and air-conditions a rear-seat side space in the vehicle interior;
A vehicle air conditioner comprising the downstream evaporator and a front seat air conditioning unit (6c) that air-conditions a front seat side space in the vehicle interior.

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