JP2000283577A - Refrigeration cycle for refrigerating plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently cope with the variation of refrigeration load and establish a refrigerating cycle even when an efficiency of an ejector incorporated into the cycle is lowered. SOLUTION: A refrigerating cycle 17 consists of a first refrigerant passage 21 in which liquid phase refrigerant flowed out from an accumulator 34 is supplied to a sucking portion 42 of an ejector 33 through a main evaporator 11, a second refrigerant passage 22 in which the liquid phase refrigerant flowed out from the accumulator 34 is supplied to a suction port of a compressor 31 through a sub-evaporator 12, and a third refrigerant passage 23 in which gas phase refrigerant flowed out from the accumulator 34 is supplied to the suction port of the compressor 31 through a thermostatic variable throttle valve 37. When the efficiency of the ejector 33 is lowered, that is, when SH rate at an exit of the sub-evaporator 12 is higher than a given value, the variable throttling travel of the valve 37 is narrowed, thereby permitting the refrigerant to flow to the sub-evaporator 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle for a refrigeration system incorporating a refrigerant compressor, a refrigerant condenser, an ejector, an accumulator, a first refrigerant evaporator, a second refrigerant evaporator, and a variable throttle valve. .

[0002]

2. Description of the Related Art Conventionally, a refrigerant circulation circuit in which a refrigerant compressor, a refrigerant condenser, an ejector, and a gas-liquid separator are circularly connected by a refrigerant pipe, and a liquid-phase refrigerant separated from a gas-phase refrigerant by a gas-liquid separator. A refrigeration cycle for a refrigerating apparatus has been proposed in which a suction pipe is provided to a suction unit of an ejector, and a refrigerant evaporator is provided in the middle of the bypass pipe.

Japanese Patent Application Laid-Open No. 5-321421 discloses a refrigerant circuit in which a refrigerant compressor, a refrigerant condenser, an ejector, a first refrigerant evaporator and a gas-liquid separator are circularly connected by a refrigerant pipe. A refrigerating apparatus comprising: a bypass pipe configured to cause a suction part of an ejector to suck a liquid-phase refrigerant separated from a gas-phase refrigerant by a separator; and a second refrigerant evaporator is provided in the middle of the bypass pipe. A refrigeration cycle has been proposed.

This refrigeration cycle for a refrigeration system increases the refrigeration capacity during low-speed operation of the refrigerant compressor by adjusting the flow rate of the refrigerant passing through the ejector, or increases the refrigeration capacity that has room during high-speed operation of the refrigerant compressor. A variable throttle valve is provided in the ejector for the purpose of optimizing and reducing the power of the refrigerant compressor.

[0005]

However, the ejector incorporated in the conventional refrigeration cycle for a refrigerating apparatus has a simple structure and a fixed shape of the mixing section. When the efficiency of the refrigerant is deteriorated, the pressure loss of the refrigerant flowing through the refrigerant evaporator becomes larger than the pressure rise by the ejector. As a result, it becomes difficult for the refrigerant to flow through the refrigerant evaporator, so that there has been a problem that the cycle is not established.

As one of the countermeasures, Japanese Unexamined Patent Application Publication No. 5-31
As disclosed in Japanese Patent No. 2421, a refrigeration cycle for a refrigeration system having a variable throttle valve for increasing or decreasing the nozzle diameter in a nozzle in an ejector has been proposed. When the efficiency of the ejector deteriorates only when the control can be performed, there has been a problem that the fluctuation of the refrigeration load cannot be sufficiently coped with.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to sufficiently cope with fluctuations in the refrigerating load even when the efficiency of the ejector has deteriorated by flowing the refrigerant to the second refrigerant evaporator when the efficiency of the ejector has deteriorated. It is an object of the present invention to provide a refrigeration cycle for a refrigeration apparatus, which is capable of achieving a cycle.

[0008]

Means for Solving the Problems Claims 1 and 2
According to the invention described in (1), the gas-phase refrigerant discharged from the discharge port of the refrigerant compressor passes through the refrigerant condenser and the ejector, flows into the gas-liquid separator, and is separated into gas and liquid. Then, the liquid-phase refrigerant flowing out from the liquid-phase refrigerant side of the gas-liquid separator passes through the first pressure reducing means and the first refrigerant evaporator and is sucked into the suction part of the ejector. The gas-phase refrigerant flowing out of the gas-liquid separator of the gas-liquid separator passes through the variable throttle means and is sucked into the suction port of the refrigerant compressor.

At this time, when the efficiency of the ejector detected by the ejector efficiency detecting means is lower than a predetermined value, or when the refrigerant temperature at the outlet of the second refrigerant evaporator detected by the refrigerant temperature detecting means is higher than the predetermined value. In this case, by reducing the passage cross-sectional area of the third refrigerant passage by the variable throttle unit, the liquid-phase refrigerant flowing out from the liquid-phase refrigerant side of the gas-liquid separator passes through the second decompression unit and the second refrigerant evaporator. It passes through and is sucked into the suction port of the refrigerant compressor.

As a result, when the efficiency of the ejector is deteriorated, the refrigerant flows not only to the first refrigerant evaporator but also to the second refrigerant evaporator. Can respond to
In addition, a cycle can be established.

According to the third and fourth aspects of the present invention, the lower the efficiency of the ejector detected by the ejector efficiency detecting means, or the lower the outlet of the second refrigerant evaporator detected by the refrigerant temperature detecting means. The liquid-phase refrigerant flowing out from the liquid-phase refrigerant side of the gas-liquid separator is reduced by the second refrigerant pressure reducing means and the second refrigerant by reducing the passage cross-sectional area of the third refrigerant passage by the variable restrictor as the refrigerant temperature increases. After passing through the evaporator, it is sucked into the suction port of the refrigerant compressor.

As a result, when the efficiency of the ejector is deteriorated, the refrigerant flows not only to the first refrigerant evaporator but also to the second refrigerant evaporator. Can respond to
In addition, a cycle can be established.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Configuration of First Embodiment] An embodiment of the present invention will be described with reference to the drawings based on an embodiment. FIG.
4 to 4 show a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a refrigeration cycle of the vehicle air conditioner, and FIG. 2 is a diagram illustrating an air conditioner unit of the vehicle air conditioner.

The vehicle air conditioner of this embodiment includes an air conditioner unit in which a cooling unit and a condensing unit are integrated with a sub engine 8 provided separately from a vehicle running engine. This air conditioner unit is mounted on a bus vehicle and is, for example, a type housed under the floor of a passenger seat of the bus vehicle.

The cooling unit includes an air conditioning duct 9 for sending air toward the passenger compartment of a bus vehicle, a blower 10 connected to the air conditioning duct 9, a main evaporator 11 provided inside the air conditioning duct 9, and a sub-evaporator. 1
2 and a heater core 13 and the like.

The blower 10 is a centrifugal fan that is driven to rotate by the sub-engine 8, and sucks air inside the vehicle or air outside the vehicle, and blows out the air that has passed through the air conditioning duct 9 toward the vehicle interior. Things. The heater core 13 is a heating heat exchanger that heats air passing through the inside of the air conditioning duct 9 by exchanging heat with cooling water and heats the air.
The main evaporator 11 and the sub-evaporator 12 are arranged so as to heat all the air that has passed therethrough.

The condensing unit includes a shroud case 14 in which the outside air flows forcibly, a radiator 15 for forcibly exchanging heat with the vehicle outside air, and a condenser 16,
A cooling fan (not shown) and the like are arranged at the downstream end of the shroud case 14 in the air.

The radiator 15 is connected to the sub engine 8
This is a means for radiating cooling water for maintaining the temperature in a predetermined temperature range. The cooling fan is an axial fan that is driven to rotate by the sub-engine 8, and that drives the sub-engine 8 to suck air outside the vehicle compartment into the shroud case 14 to forcibly cool the radiator 15 and the condenser 16. It is.

Next, the refrigeration cycle 17 of the vehicle air conditioner of this embodiment will be described with reference to FIGS.
The refrigerating cycle 17 of the present embodiment corresponds to the refrigerating cycle for a refrigerating apparatus of the present invention, and includes a refrigerant passage 20, a first refrigerant passage 21, a second refrigerant passage 22, a third refrigerant passage 23, and the like. .

The refrigerant passage 20 is used to transfer the gas-phase refrigerant discharged from the discharge port of the compressor 31 to the condenser 16,
A refrigerant flow path that flows into an accumulator (gas-liquid separator) 34 via a pressure-operated variable throttle valve 32 and an ejector 33. The first refrigerant passage 21 is a first bypass passage through which the liquid-phase refrigerant flowing out from the liquid-phase refrigerant side of the accumulator 34 flows into the suction portion of the ejector 33 via the temperature-operated expansion valve 35 and the main evaporator 11. is there.

The second refrigerant passage 22 is connected to the accumulator 3
The liquid-phase refrigerant flowing out from the liquid-phase refrigerant side of No. 4 is
And a second bypass flow path that flows into the suction port of the compressor 31 via the sub-evaporator 12. The third refrigerant passage 23 is a refrigerant passage through which the gas-phase refrigerant flowing out from the gas-phase refrigerant side of the accumulator 34 flows into the suction port of the compressor 31 via the temperature-operated variable throttle valve 37. Configure the circuit.

The main evaporator 11 and the sub-evaporator 12 are arranged over the entire surface of the air conditioning duct 9 so as to be able to cool all air passing through the air conditioning duct 9. And the main evaporator 11
The first refrigerant evaporator cools the air by exchanging heat between the gas-liquid two-phase refrigerant flowing therein and the air passing through the air conditioning duct 9, and evaporates and evaporates the refrigerant.

The sub-evaporator 12 is disposed in parallel with the main evaporator 11, and cools the air by exchanging heat between the gas-liquid two-phase refrigerant flowing therein and the air passing through the air conditioning duct 9. And a second refrigerant evaporator for evaporating and evaporating the refrigerant. The capacitor 16 is disposed in the shroud case 14 and the shroud case 1
4 is provided so as to be able to exchange heat with the outside air passing through the vehicle interior. The condenser 16 is a refrigerant condenser that exchanges heat between a gas-phase refrigerant flowing into the inside and air outside the vehicle compartment to condense and liquefy the gas-phase refrigerant.

The compressor 31 is a refrigerant compressor which is driven to rotate by the sub engine 8 to suck, compress and discharge the refrigerant. The ejector 33 includes the capacitor 16
The liquid-phase refrigerant flowing from the nozzle is ejected from the nozzle 41 to perform atomization under reduced pressure. Then, the gas-phase refrigerant is sucked from the suction part 42, and the liquid-phase refrigerant and the gas-phase refrigerant are mixed and pressurized in the mixing part in the diffuser 43, and then the gas-liquid two-phase refrigerant is sent to the accumulator 34.

The pressure-operated variable throttle valve 32 has a valve body (not shown) having a communication hole (corresponding to a refrigerant passage) formed therein, and a valve body (not shown) for changing the opening of the communication hole of the valve body. And a refrigerant pressure detector (not shown) for detecting the high pressure (condensation pressure) of the refrigeration cycle 17.

The pressure-operated variable throttle valve 32 operates such that the higher the high pressure detected by the refrigerant pressure detector, ie, the higher the rotational speed of the compressor 31, the greater the flow rate of the refrigerant. The passage cross-sectional area of the passage 20 is increased. Further, the accumulator 34 separates the refrigerant flowing from the refrigerant inlet into gas and liquid, and only the liquid-phase refrigerant flows out from the liquid-phase refrigerant side outlet, and only the gas-phase refrigerant flows out from the gas-phase refrigerant side outlet.

The temperature-operated expansion valve 35 has a valve body (not shown) having a communication hole (corresponding to a second refrigerant passage) formed therein, and changes the opening of the communication hole of the valve body. Valve (not shown), temperature-sensitive cylinder 4 for detecting refrigerant temperature (degree of superheat, superheat amount) at outlet of main evaporator 11
4, and a capillary tube connecting the valve body and the temperature-sensitive cylinder 44.

The temperature-operated expansion valve 35 is provided with a first pressure reducing means such as an expansion valve for reducing the refrigerant by reducing the passage cross-sectional area of the first refrigerant passage 21 as the degree of superheat at the outlet of the main evaporator 11 is increased. It is. Also,
The fixed throttle 36 is a second pressure reducing means such as a capillary tube or an orifice that reduces the pressure of the refrigerant by reducing the passage cross-sectional area of the second refrigerant passage 22.

The temperature-operated variable throttle valve 37 includes a valve body (not shown) having a communication hole (corresponding to a third refrigerant passage) formed therein, and a valve for changing the opening of the communication hole of the valve body. Body (not shown), a temperature-sensitive cylinder (ejector efficiency detection means, refrigerant temperature detection means, etc.) 45 for detecting a refrigerant temperature (superheat degree, superheat amount, hereinafter referred to as SH amount) at an outlet of the sub-evaporator 12, and a valve It has a capillary tube for connecting the main body and the temperature sensing tube 45.

The temperature-operated variable throttle valve 37 is a variable throttle means such as an expansion valve for increasing or decreasing the cross-sectional area of the third refrigerant passage 23 of the refrigeration cycle 17 based on the SH amount at the outlet of the sub-evaporator 12. is there. The temperature-operated variable throttle valve 37 reduces the passage cross-sectional area of the third refrigerant passage 23 as the SH amount of the sub-evaporator 12 increases. The temperature-operated variable throttle valve 37 is configured such that the smaller the SH amount of the sub-evaporator 12 is, the more the third refrigerant passage 23
Passage cross-sectional area is increased.

[Operation of First Embodiment] Next, the operation of the vehicle air conditioner of this embodiment will be briefly described with reference to FIGS. Here, FIG. 3 shows the refrigeration cycle 1 in FIG.
7 shows the state points of the refrigerant in the refrigerant circuit of FIG. 7 on a Mollier diagram.
3 corresponds to 1 to 7 on the Mollier diagram in FIG.

The PE in FIG. 3 is the low pressure of the refrigeration cycle 17 (the evaporation pressure of the main evaporator 11).
C is the suction pressure of the compressor 31, and PM is the outlet pressure of the ejector 33. ΔP is the pressure of the ejector 33, Δh is the enthalpy difference between the nozzle entrance and exit,
Is the compressor power.

The high-temperature, high-pressure gas-phase refrigerant compressed by the compressor 31 (state point 7) is condensed and liquefied by the condenser 16 to become a high-temperature, high-pressure liquid-phase refrigerant (state point 1). The ejector 3 passes through the type variable throttle valve 32.
3 flows into. Then, the liquid-phase refrigerant flowing into the ejector 33 is decompressed when passing through the nozzle 41, reaches a state point 2 at the outlet of the nozzle 41, and is further pressurized when passing through the diffuser 43, and the outlet of the diffuser 43 Then, state point 3 is reached.

Here, the nozzle 41 of the ejector 33 is
The first refrigerant passage 21 is inserted into the suction part 42 of the ejector 33 by utilizing the pressure drop around the refrigerant that is ejected at a high speed from the nozzle 41 when the liquid-phase refrigerant flowing from the condenser 16 passes.
, The gas-phase refrigerant at state point 5 is sucked. Therefore, the liquid-phase refrigerant flowing from the refrigerant passage 20 and the gas-phase refrigerant sucked from the first refrigerant passage 21 are mixed in the mixing section in the diffuser 43. As a result, the gas-liquid two-phase refrigerant flowing out of the ejector 33 is discharged from the state point 2, the state point 5, and the condenser 1
State point 3 is determined by the refrigerant flow from the main evaporator 11 and the refrigerant flow from the main evaporator 11.

Thereafter, the gas-liquid two-phase refrigerant is supplied to the refrigerant passage 20.
Flows into the accumulator 34 to be separated into gas and liquid. The gas-phase refrigerant flows out of the gas-phase refrigerant-side outlet of the accumulator 34 by the suction force of the compressor 31, and is sucked into the suction port of the compressor 31 through the third refrigerant passage 23. The flow rate of the refrigerant passing through the third refrigerant passage 23 is adjusted by the variable throttle opening of the temperature-operated variable throttle valve 37 that is changed based on the SH amount at the outlet of the sub-evaporator 12.

On the other hand, the liquid-phase refrigerant (state point 4) in the accumulator 34 is sucked by the suction part 42 of the ejector 33, flows out from the liquid-phase refrigerant side outlet of the accumulator 34, and passes through the first refrigerant passage 21. It flows into the temperature-operated expansion valve 35. Then, when passing through the temperature-operated expansion valve 35, the pressure is reduced and becomes a gas-liquid two-phase refrigerant and flows into the main evaporator 11. The gas-liquid two-phase refrigerant flowing into the main evaporator 11 evaporates and evaporates when passing through the main evaporator 11 (state point 5).
3 is sucked by the suction unit 42.

Here, when the efficiency of the ejector 33 is reduced due to the fluctuation of the refrigeration load (cooling load) of the refrigeration cycle 17, the pressure loss of the refrigerant flowing through the main evaporator 11 becomes larger than the pressure increase by the ejector 33. As a result, the suction force of the suction part 42 of the ejector 33 is reduced, and the amount of the liquid-phase refrigerant sucked into the first refrigerant passage 21 from the liquid-phase refrigerant-side outlet of the accumulator 34 is reduced. Therefore, the main evaporator 1
Since it is difficult for the refrigerant to flow in the first cycle, there is a possibility that the cycle is not established.

Therefore, in this embodiment, the second refrigerant passage 22 is provided for connecting the liquid-phase refrigerant-side outlet of the accumulator 34 and the suction port of the compressor 31.
The sub-evaporator 12 is arranged in the middle of 2. Further, a temperature-operated variable throttle valve 37 that changes the passage cross-sectional area based on the SH amount of the sub-evaporator 12 is disposed in the third refrigerant passage 23 of the refrigeration cycle 17.

When the SH amount of the sub-evaporator 12 detected by the temperature-sensitive cylinder 45 is higher than a predetermined value (for example, 10 ° C.), the opening of the temperature-operated variable throttle valve 37 is reduced. The passage cross-sectional area of the third refrigerant passage 23 of the refrigeration cycle 17 is reduced, and the refrigerant flows to both the main evaporator 11 and the sub-evaporator 12.

FIG. 4 shows the efficiency of the ejector 33 (η
e) The refrigerant flow rate distribution (Gemain / G) between the refrigerant flow rate (Gemain) flowing in the main evaporator 11 and the refrigerant flow rate (Gesub) flowing in the sub-evaporator 12
It is the graph which showed e). Here, Ge is the sum of Gemain and Gesub as shown in the following equation (1).

## EQU1 ## Ge = Gemain + Gesub

Therefore, when the efficiency of the ejector 33 is degraded, that is, when the pressure increase in the diffuser 43 of the ejector 33 is small, the accumulator 3
The liquid-phase refrigerant (state point 4) in the pump 4 is sucked by the compressor 31, flows out of the liquid-phase refrigerant-side outlet of the accumulator 34, and flows into the second refrigerant passage 22. The liquid-phase refrigerant flowing into the second refrigerant passage 22 is decompressed by the fixed throttle 36 and becomes a gas-liquid two-phase refrigerant and flows into the sub-evaporator 12. Then, the gas-liquid two-phase refrigerant flowing into the sub-evaporator 12 evaporates and evaporates when passing through the sub-evaporator 12 (state point 6), and is then sucked into the suction port of the compressor 31.

Thereafter, when the amount of SH at the outlet of the sub-evaporator 12 becomes lower than a predetermined value (for example, 5 ° C.) due to the refrigerant flowing through the sub-evaporator 12, the opening degree of the temperature-operated variable throttle valve 37 becomes large. Refrigeration cycle 17
The cross-sectional area of the third refrigerant passage 23 increases, the amount of refrigerant flowing through the sub-evaporator 12 decreases, and the amount of refrigerant flowing through the main evaporator 11 increases.

Therefore, as the efficiency of the ejector 33 increases, that is, as the pressure increase in the diffuser 43 of the ejector 33 increases, the refrigerant flows to the main evaporator 11 and the main evaporator 1
There is only one refrigeration cycle 17. That is, in the refrigeration cycle 17 of the present embodiment, the refrigerant flow distribution is determined by the pressure loss of the main evaporator 11 and the pressure loss of the sub-evaporator 12, and the ejector 33 of any efficiency can be operated.

[Effects of the first embodiment] As described above, the refrigeration cycle 17 of the vehicle air conditioner of the present embodiment is operated when the efficiency of the ejector 33 is reduced, that is, when the diffuser 43 of the ejector 33 is used. When the pressure increase decreases, the SH amount at the outlet of the sub-evaporator 12 increases, so that the opening of the temperature-operated variable throttle valve 37 decreases, and the cross-sectional area of the third refrigerant passage 23 decreases.

As a result, the refrigerant flows not only in the main evaporator 11 but also in the sub-evaporator 12, so that even if the efficiency of the ejector 33 is reduced, a cycle can be established and the refrigeration cycle 1
7 can sufficiently cope with the fluctuation of the refrigeration load.

[Second Embodiment] FIGS. 5 and 6 show a second embodiment of the present invention. FIG. 5 is a diagram showing an air conditioning control device of a vehicle air conditioner.

In this embodiment, an electric motor is provided instead of the temperature-operated variable throttle valve of the first embodiment in the third refrigerant passage 23 connecting the gas-phase refrigerant-side outlet of the accumulator 34 and the suction port of the compressor 31. A variable throttle valve (corresponding to variable throttle means of the present invention) 51 is arranged, and the variable throttle opening of the electric variable throttle valve 51 is controlled by an air conditioning control device 52.

The electric variable throttle valve 51 has a valve body (not shown) having a communication hole (corresponding to a third refrigerant passage) formed therein, and a valve body for changing the opening of the communication hole of the valve body. (Not shown), and a valve body driving means (not shown) such as an electromagnetic coil for driving the valve body.

The air-conditioning control device 52 has a CPU, an RO,
A variable throttle control means provided with a well-known microcomputer comprising M, RAM, etc.
3 is supplied to the A / A by an input circuit (not shown).
After being D-converted, it is configured to be input to a microcomputer.

The refrigerant temperature sensor 53 is an ejector efficiency detecting means and a refrigerant temperature detecting means for detecting the refrigerant temperature at the outlet of the sub-evaporator 12 (degree of superheat, superheat amount, hereinafter referred to as SH amount). And the air-conditioning control device 52
The variable throttle opening of the electric variable throttle valve 51 is controlled based on the SH amount at the outlet of the sub-evaporator 12 so as to increase or decrease the cross-sectional area of the third refrigerant passage 23 of the refrigeration cycle 17.

FIG. 6 is a flowchart showing the variable throttle control by the air conditioning controller 52. First, SH at the outlet of the sub-evaporator 12 is detected by the refrigerant temperature sensor 53.
The amount is detected (step S1). Next, it is determined whether the SH amount of the sub-evaporator 12 is higher than a predetermined value (for example, 10 ° C.) (Step S2). If the result of this determination is YES, a control signal is output to the electric variable throttle valve 51 so as to reduce the cross-sectional area of the third refrigerant passage 23 (step S3). Thereafter, the process returns to the control processing of step S1.

If the result of the determination in step S2 is NO, it is determined whether or not the SH amount of the sub-evaporator 12 is lower than a predetermined value (for example, 5 ° C.) (step S4). If this determination result is NO, step S
It returns to the control processing of No. 1. If the determination result in step S4 is YES, a control signal is output to the electric variable throttle valve 51 so as to increase the cross-sectional area of the third refrigerant passage 23 (step S5). Thereafter, the process returns to the control processing of step S1.

The amount of increase or decrease (variation of the opening) of the electric variable throttle valve 51 by the variable throttle opening control may be increased or decreased by a predetermined amount in a stepwise manner or continuously. Further, the electric variable throttle valve 51 may be changed to a variable throttle unit such as an electromagnetic open / close valve that only opens and closes the third refrigerant passage 23.

[Modification] In the present embodiment, the present invention is applied to the refrigeration cycle 17 of the air conditioner for a bus vehicle. However, the air conditioner for a large vehicle other than a bus vehicle, a vehicle such as a passenger car or an automobile, and the air conditioner for a vehicle The present invention may be applied to a refrigeration cycle of a vehicle refrigeration device or a vehicle refrigeration device. Further, the present invention may be applied to a refrigeration cycle for a stationary refrigeration apparatus.

In this embodiment, the blower 10 and the compressor 31 are rotationally driven by an auxiliary engine (sub-engine) 8 different from the power engine for driving the vehicle, but the blower 10 or the compressor 31 is driven by the power engine for driving the vehicle. It may be driven to rotate. Further, the blower 10 or the compressor 31 may be rotationally driven by another driving means such as an electric motor.

In this embodiment, the pressure-operated variable throttle valve 32 for reducing the degree of subcooling (degree of supercooling) at the inlet of the nozzle 41 of the ejector 33 is provided between the condenser 16 and the ejector 33. The pressure-operated variable throttle valve 32 may not be provided. Further, the variable throttle valve opening may be configured to increase as the rotational speed of the compressor 31 increases.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a refrigeration cycle (first embodiment).

FIG. 2 is a perspective view showing an air conditioner unit (first example).
Example).

FIG. 3 is a Mollier diagram of a refrigeration cycle (first embodiment).

FIG. 4 is a graph showing a distribution of a refrigerant flow rate between a refrigerant flow rate flowing in a main evaporator and a refrigerant flow rate flowing in a sub-evaporator with respect to the efficiency of an ejector (first embodiment).

FIG. 5 is a block diagram showing an air-conditioning control device (second embodiment);
Example).

FIG. 6 is a flowchart showing variable throttle control by an air conditioning control device (second embodiment).

[Explanation of symbols]

Reference Signs List 8 sub-engine 11 main evaporator (first refrigerant evaporator) 12 sub-evaporator (second refrigerant evaporator) 16 condenser (refrigerant condenser) 17 refrigeration cycle 20 refrigerant passage 21 first refrigerant passage 22 second refrigerant passage 23 third refrigerant Passage 31 Compressor (refrigerant compressor) 33 Ejector 34 Accumulator (gas-liquid separator) 35 Temperature-operated expansion valve (first pressure reducing means) 36 Fixed throttle (second pressure reducing means) 37 Temperature-operated variable throttle valve (variable throttle means) 41) Nozzle 42 Suction unit 43 Diffuser 44 Temperature sensing cylinder 45 Temperature sensing cylinder (ejector efficiency detecting means, refrigerant temperature detecting means) 51 Electric variable throttle valve (variable throttle means) 53 Refrigerant temperature sensor

Claims (4)

[Claims] (A) a refrigerant passage through which a gas-phase refrigerant discharged from a discharge port of a refrigerant compressor flows into a gas-liquid separator via a refrigerant condenser and an ejector; and (b) the gas-liquid separation. A first refrigerant passage through which the liquid-phase refrigerant flowing out of the liquid-phase refrigerant side of the device flows into the suction portion of the ejector via the first pressure reducing means and the first refrigerant evaporator; and (c) the gas-liquid separator. A second refrigerant passage through which the liquid-phase refrigerant flowing out from the liquid-phase refrigerant side flows through a second pressure reducing means and a second refrigerant evaporator into the suction port of the refrigerant compressor; and (d) the gas-liquid separation. A third gas for flowing the gaseous refrigerant flowing out of the gaseous refrigerant side of the compressor into the suction port of the refrigerant compressor.
A refrigerant passage, and (e) ejector efficiency detection means for detecting the efficiency of the ejector, wherein when the efficiency of the ejector detected by the ejector efficiency detection means is lower than a predetermined value, the passage of the third refrigerant passage A refrigeration cycle for a refrigeration system, comprising: a variable throttle means for reducing a cross-sectional area. 2. The refrigeration cycle for a refrigeration system according to claim 1, wherein said ejector efficiency detecting means is a refrigerant temperature detecting means for detecting a refrigerant temperature at an outlet of said second refrigerant evaporator, and said variable throttle means. For reducing the cross-sectional area of the third refrigerant passage when the refrigerant temperature at the outlet of the second refrigerant evaporator detected by the refrigerant temperature detecting means is higher than a predetermined value. Refrigeration cycle. (A) a refrigerant passage through which a gas-phase refrigerant discharged from a discharge port of the refrigerant compressor flows into a gas-liquid separator via a refrigerant condenser and an ejector; and (b) the gas-liquid separation. A first refrigerant passage through which the liquid-phase refrigerant flowing out of the liquid-phase refrigerant side of the device flows into the suction portion of the ejector via the first pressure reducing means and the first refrigerant evaporator; and (c) the gas-liquid separator. A second refrigerant passage through which the liquid-phase refrigerant flowing out from the liquid-phase refrigerant side flows through a second pressure reducing means and a second refrigerant evaporator into the suction port of the refrigerant compressor; and (d) the gas-liquid separation. A third gas for flowing the gaseous refrigerant flowing out of the gaseous refrigerant side of the compressor into the suction port of the refrigerant compressor.
A refrigerant passage; and (e) ejector efficiency detection means for detecting the efficiency of the ejector. The lower the efficiency of the ejector detected by the ejector efficiency detection means, the smaller the passage cross-sectional area of the third refrigerant passage becomes. A refrigeration cycle for a refrigeration apparatus, comprising: 4. The refrigeration cycle for a refrigeration system according to claim 3, wherein said ejector efficiency detecting means is a refrigerant temperature detecting means for detecting a refrigerant temperature at an outlet of said second refrigerant evaporator, and said variable throttle means. The more the refrigerant temperature at the outlet of the second refrigerant evaporator detected by the refrigerant temperature detecting means rises,
A refrigeration cycle for a refrigeration system, wherein a cross-sectional area of the third refrigerant passage is reduced.