JP2003074992A - Refrigeration cycle apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration apparatus capable of avoiding pressure rise of a refrigerant in a high pressure side due to increase of refrigerant flow rate and simultaneously raising cooling capacity corresponding to the increase of the refrigerant flow rate. SOLUTION: A bypass passage B is provided for making part of a refrigerant flowing out of a refrigerant radiator 2 bypass an ejector 3 to flow into a gas- liquid separator 4. Control valves 7, 70 and 9 are provided in the halfway of the passage B. When the refrigerant flowing out of the radiator 2 comes to a specific pressure condition, the valves 7, 70 and 9 are opened to allow the refrigerant to flow into the passage B. Thus, the pressure of the refrigerant is surely prevented from being excessively raised, and a refrigeration cycle is stably operated. Further, even when the flow rate of the refrigerant increases, power for a refrigerant compressor 1 is prevented from increasing so that efficiency of the cycle is enhanced. Cooling capacity is raised corresponding to the increase of the refrigerant flow rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of the cooling capacity of a refrigeration cycle (ejector cycle) device using an ejector for boosting the pressure of a refrigerant by utilizing expansion power of the refrigerant.

[0002]

2. Description of the Related Art Conventionally, a method of using an ejector in a refrigerating cycle has been known, for example, Japanese Patent Laid-Open No. 6-2964.
Japanese Patent Laid-Open Publication No. 2003-242359 discloses that the expansion energy of the refrigerant is used by the ejector to circulate and pressurize the low-pressure refrigerant passing through the evaporator, thereby improving the cycle efficiency as compared with a cycle without using an ordinary ejector. .

FIG. 12 is a schematic diagram of a conventional ejector cycle. 1 is a refrigerant compressor for compressing and increasing the pressure of the refrigerant, 2
Is a refrigerant radiator for cooling the high-pressure refrigerant, 3 is an ejector,
Reference numeral 4 is a gas-liquid separator, 6 is a refrigerant evaporator, and 2a and 6a are fans for blowing air to the refrigerant radiator 2 and the refrigerant evaporator 6, respectively. Further, FIG. 13 is a sectional structural view of the ejector 3.
It is composed of a nozzle 31, a low-pressure inflow section 32, a mixing section 33, and a diffuser 34, and 31a is a high-pressure inflow section, and 35
Is the outflow part.

The operation of the ejector 3 will be described with reference to FIG. The high-pressure refrigerant flows into the nozzle 31 from the high-pressure inflow portion 31a, is decompressed by the nozzle 31, and the expansion energy of the refrigerant is converted into the kinetic energy of the refrigerant, so that the flow velocity of the refrigerant is increased, and the nozzle tip 31c is connected to the gas-liquid mixture. It spouts as a high-speed jet in a phased state. On the other hand, the low-pressure refrigerant that has exited the refrigerant evaporator 6 is sucked into the ejector 3 from the low-pressure inflow portion 32 by utilizing the pressure drop around the nozzle jet flow.

The sucked low-pressure refrigerant and the nozzle jet flow are mixed in the mixing section 33 of the ejector 3. At this time, the high-speed nozzle jet flow and the low-speed low-pressure refrigerant are mixed to transfer momentum. Then, the refrigerant is discharged from the ejector outflow portion 35 through the diffuser 34 that decelerates the mixed refrigerant and converts kinetic energy into pressure energy. Through this process, the low-pressure refrigerant is transferred to the low-pressure inlet 3 by the expansion energy of the high-pressure refrigerant.
It is boosted from the 2 side.

[0006]

In this ejector 3, since the area of the throat portion 31b of the nozzle 31 having the smallest flow passage cross-sectional area is constant, the refrigerant flow rate can be adjusted according to the operating conditions of the refrigeration cycle. Can not. In a refrigeration cycle with a small load fluctuation, it is possible to operate the refrigeration cycle by designing the area of the throat portion 31b according to a steady condition with a high operating frequency.

However, when used in a vehicle air conditioner or the like, since the refrigerant compressor 1 is driven by an engine (not shown), the rotational speed of the refrigerant compressor 1 fluctuates greatly and the refrigerant flow rate also changes greatly. Throat 31 with the same design as above
If the area of b is determined, the refrigerant pressure increases when the refrigerant flow rate increases, the power of the refrigerant compressor 1 increases and the efficiency of the refrigeration cycle deteriorates, or the refrigerant pressure increases too much and the operation continues. It will be difficult.

In particular, in a refrigeration cycle using carbon dioxide (CO ₂ ) as a refrigerant for defluorocarbon, the high pressure side operates at a pressure of about 10 times that of conventional freon, and the refrigerant does not condense even at high pressure. Since it is a cycle, the amount of change in pressure is larger than that of CFC for the same rate of change of the refrigerant flow rate, and the pressure tends to change rapidly, which makes it difficult to operate the refrigeration cycle stably.

Further, in an air conditioner for an electric vehicle or a home air conditioner using an electric refrigerant compressor, a large cooling capacity may be required and a large refrigerant flow rate may be required as in a cool down. The same problems as those of the vehicle air conditioner may occur.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to avoid the increase of the refrigerant pressure due to the increase of the refrigerant flow rate and to improve the cooling capacity corresponding to the increase of the refrigerant flow rate. It is to provide a refrigeration cycle device that can be improved.

[0011]

In order to achieve the above object, the present invention employs the following technical means.

According to the first aspect of the present invention, the bypass flow passage (B) for allowing a part of the refrigerant discharged from the refrigerant radiator (2) to bypass the ejector (3) and flow into the gas-liquid separator (4). And a control valve (7, 70, 9) in the middle of the bypass flow path (B), and when the refrigerant discharged from the refrigerant radiator (2) reaches a predetermined pressure condition, the control valve (7 ,
70, 9) are opened to allow the refrigerant to flow into the bypass flow passage (B).

This is because when the refrigerant flow rate increases and the refrigerant pressure on the high-pressure side becomes unnecessarily high, a part of the high-pressure refrigerant is branched so as to bypass the ejector (3) and flow at a high pressure. This is to avoid the pressure increase on the side. As a result, it is possible to reliably prevent the refrigerant pressure from rising too high, and to operate the refrigeration cycle in a stable manner. Further, even when the refrigerant flow rate increases, an increase in power of the refrigerant compressor (1) is suppressed, and cycle efficiency is improved. .

The liquid refrigerant that has passed through the bypass flow path (B) flows through the refrigerant evaporator (6) as described above together with the liquid refrigerant that has passed through the ejector (3) to exert the effect of cooling. Therefore, when a large cooling capacity is required, such as during cool down, by flowing the refrigerant through the bypass flow path (B), the flow rate through the refrigerant evaporator (6) can be made larger than in the conventional case, so that a larger cooling capacity can be obtained. Obtainable.

According to the second aspect of the present invention, a part of the refrigerant discharged from the refrigerant radiator (2) is bypassed through the ejector (3), the gas-liquid separator (4) and the flow rate control valve (5). A bypass flow path (B) for flowing into the evaporator (6) is provided, and a control valve (7, 7) is provided in the middle of the bypass flow path (B).
0, 9) are provided so that the control valve (7, 70, 9) is opened so that the refrigerant flows through the bypass flow passage (B) when the refrigerant discharged from the refrigerant radiator (2) has a predetermined pressure condition. It is characterized by having done.

Also in this case, when the refrigerant flow rate increases and the refrigerant pressure on the high pressure side becomes unnecessarily high, a part of the high pressure refrigerant is branched so as to flow by bypassing the ejector (3). This is to avoid the pressure rise of.

A flow rate control valve (5) may be provided in the refrigerant flow path on the side of the refrigerant evaporator 6, and even if a part of the high pressure refrigerant is branched to flow through the ejector (3), the flow rate of this flow rate is increased. It is conceivable that the flow rate of the refrigerant is throttled by the control valve (5) and the pressure increase on the high pressure side cannot be avoided as expected. In the case of the present invention, since the flow rate control valve (5) is also bypassed to flow into the refrigerant evaporator (6), it is possible to reliably prevent the refrigerant pressure from rising too high, thereby stabilizing the refrigeration cycle. In addition, the operation of the refrigerant compressor (1) is suppressed from increasing even when the refrigerant flow rate increases, and the cycle efficiency improves.

Also in this embodiment, when the refrigerant bypassing the ejector (3) passes through the refrigerant evaporator 6, it exerts a cooling effect together with the liquid refrigerant from the gas-liquid separator (4), so that it is cool. When a large cooling capacity is required, such as during downtime, the flow rate through the refrigerant evaporator (6) can be increased as compared with the conventional case, and thus a larger cooling capacity can be obtained.

In the invention according to claim 3, the control valve (7, 7)
Reference numeral 0) forms a part of the refrigerant flow passage (A) from the refrigerant radiator (2) to the ejector (3) and also communicates with the refrigerant flow passage (A) to the bypass flow passage (B). (76)
And has a closed space (79) in which the refrigerant gas is enclosed at a predetermined density in the refrigerant flow path (A), and the closed space (79) is formed.
A displacement member (72) that is displaced according to a pressure difference between the inside and outside, and a valve body (71) that opens and closes the valve port (76) in conjunction with the displacement member (72) are provided, and When the pressure exceeds the pressure in the closed space (79), the displacement member (72) is displaced and the valve port (76) is opened.

This is because when the internal pressure of the refrigerant passage (A) on the high pressure side is equal to or lower than the internal pressure of the closed space (79) which is a predetermined pressure, all the refrigerant discharged from the radiator (2) is ejected ( 3)
But the internal pressure of the refrigerant channel (A), which is the high pressure side,
When the pressure in the closed space (79), which is a predetermined pressure, is exceeded, a part of the high-pressure refrigerant flows in the bypass flow path (B), so it is possible to avoid a high pressure increase due to an increase in the refrigerant flow rate.

Further, since the pressure in the closed space (79) of the control valve (7, 70) changes according to the temperature of the high pressure refrigerant discharged from the radiator (2), the control valve (7, 70) is opened. The pressure also changes according to the high-pressure refrigerant temperature, and the valve opening pressure almost matches the optimum control line that maximizes the COP (coefficient of performance of the refrigeration cycle), so that the cycle operation can be controlled under a high COP condition. .

In the invention according to claim 4, the control valve (9)
Is the pressure of the refrigerant leaving the refrigerant radiator (2) on the upstream side of the valve, the refrigerant pressure in the gas-liquid separator (4) on the downstream side of the valve, or the refrigerant in the refrigerant evaporator (6). It is characterized in that the valve is opened when a predetermined pressure difference with respect to the pressure is exceeded.

The control valve (9) of the present invention is a differential pressure valve (9) that opens when the differential pressure across the valve exceeds a predetermined value. By using this differential pressure valve (9), when the cooling load is large and the pressure inside the refrigerant evaporator (6) is high, that is, the pressure inside the gas-liquid separator (4) is also high, the ejector (3).
When the refrigerant pressure for bypassing is high, the cooling load is small and the refrigerant evaporator (6) internal pressure is low, that is, the gas-liquid separator (4) internal pressure is also low, the ejector (3)
It is possible to control the pressure of the refrigerant that bypasses the low.

In the case of the CO ₂ cycle using CO ₂ to the refrigerant, when the outlet refrigerant temperature of the refrigerant radiator (2) are the same, since the refrigerant pressure increases contributes enthalpy difference in the cooling higher, the cooling load When the load is large, the pressure for opening the differential pressure valve (9) is high and the cooling capacity is large, and when the load of cooling is small, the pressure for opening the differential pressure valve (9) is low and the cooling capacity is small, and the compressor is The increase in power of (1) is suppressed, and the decrease in COP is also suppressed.

According to the fifth aspect of the invention, the gas-liquid separator (4) includes the ejector (3) and the control valve (9).
Alternatively, it is integrated. As a result, the number of parts as a whole is reduced, and processing / assembly is facilitated. In addition, the apparatus becomes compact and the number of pipelines that connect the various equipments such as the bypass channel (B) can be reduced, so that the mountability and the assemblability on a vehicle or the like are improved. Incidentally, the reference numerals in parentheses of the above-mentioned respective means are examples showing the corresponding relationship with the concrete means described in the embodiments described later.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic diagram of an ejector cycle according to a first embodiment of the present invention. Carbon dioxide (CO ₂ ) is used as the refrigerant. Reference numeral 1 is a refrigerant compressor for compressing the refrigerant from low pressure to high pressure, 2 is a refrigerant radiator for radiating heat from the high pressure refrigerant, 3 is an ejector for circulating and boosting the low pressure refrigerant by utilizing energy for expanding the refrigerant.
Is a gas-liquid separator that separates the gas-liquid two-phase refrigerant discharged from the ejector 3 into a gas phase and a liquid phase, and sends the gas phase to the refrigerant compressor 1 and the liquid phase to the refrigerant evaporator 6 side; It is a vessel. Also, 2
Reference characters a and 6a are fans that blow air to the refrigerant radiator 2 and the refrigerant evaporator 6, respectively.

A branch is provided in the middle of the refrigerant flow path A connecting the refrigerant radiator 2 and the ejector 3, and a control valve 7 for controlling the branch of the refrigerant there, and the control valve 7 is connected to the gas-liquid separator 4. A coolant channel B is provided. FIG. 2 is a cross-sectional structural view of the control valve 7 applied to this ejector cycle.
Incidentally, this structure is disclosed in Japanese Patent Application Laid-Open No. 9-264
It is similar to the control valve described in Japanese Patent No. 622.

A diaphragm (displacement member) 72 to which the valve body 71 is joined, and an upper case 73 sandwiching the diaphragm 72.
There is a lower case 74, which is welded at the outer peripheral portion 75. Reference numeral 76 denotes a valve opening communicating with the bypass passage B, and the valve passage 71 is opened and closed according to the displacement of the diaphragm 72, so that the bypass passage B is opened and closed between the valve body 71 and the valve opening 76.

A closed space 79 is formed by the upper case 73 and the diaphragm 72. In this closed space 79, CO ₂ is about 600 kg / m with respect to the internal volume of the closed space 79 with the valve body 71 closed. Enclosed at a density of ³ .
Reference numeral 80 denotes a sealing port for sealing CO _2, which is sealed by a sealing portion 81 by welding or brazing. The high-pressure refrigerant flowing from the refrigerant radiator 2 to the ejector 3 flows around the upper case 736 and the lower case 74, and the temperature in the closed space 79 is substantially equal to the surrounding high-pressure refrigerant temperature.

The upper case 73, the diaphragm 72,
The parts obtained by welding the lower case 74 are the flow path housing 82.
It is fixed to the stay 83 provided in the above by means of a fixing metal fitting 84 by screwing, welding or the like. Reference numeral 85 is a refrigerant flow path to the lower case 74 side. The rod 77 is joined to the valve body 71, and a compression coil spring 78 exerts a force in a direction of closing the valve.

This is because when the refrigerant pressure is below the critical pressure and the high-pressure side refrigerant is flowing in a gas-liquid two-phase state, the closed space 79
The internal temperature and the surrounding high-pressure-side refrigerant temperature become equal, the internal pressure of the closed space 79 (saturation pressure at that temperature) and the high-pressure-side refrigerant pressure become the same, and the force to close the valve does not act, and the bypass flow The refrigerant is prevented from flowing into the passage B, and the control valve is opened when the degree of supercooling of the refrigerant reaches a predetermined value. The spring force is the diaphragm 72.
In terms of pressure, it is about 0.6 MPa (pressure corresponding to a supercooling degree of about 5 ° C. when the high-pressure side refrigerant pressure is below the critical pressure when the valve is opened).

The operation of the control valve 7 will be described. Since about 600 kg / m ³ of CO ₂ is enclosed in the enclosed space 79, the internal pressure and temperature of the enclosed space 79 are along the isopycnic line of 600 kg / m ³ shown in the Mollier diagram of CO ₂ in FIG. Change.

Therefore, for example, the temperature in the closed space 79 is 40
When the high temperature side refrigerant pressure is less than 10.3 MPa in the closed space 79 and the pressure in the closed space 79 is higher than the pressure in the closed space 79 + the spring, the diaphragm 72 has a larger pressure. When pushed downward in the figure, the valve body 71 and the valve opening 76 hit each other to close the valve, and the refrigerant does not flow in the bypass flow passage B. Conversely, the high-pressure side refrigerant pressure is 10.3MP
When a is exceeded, the valve opens and the refrigerant flows through the bypass flow passage B.

Next, the operation of the refrigeration cycle will be described. When the refrigerant flow rate is low and the high-pressure side refrigerant pressure is lower than the valve opening pressure of the control valve 7, the control valve 7 is closed, so that all the refrigerant passes through the ejector 3 and operates similarly to the conventional ejector cycle.

However, when the refrigerant flow rate increases and the high pressure side refrigerant pressure rises and exceeds the opening pressure of the control valve 7, the control valve 7
Is opened and a part of the refrigerant discharged from the refrigerant radiator 2 is decompressed by the control valve 7 and then flows through the bypass flow path B to the gas-liquid separator 4. The refrigerant that has entered the gas-liquid separator 4 mixes with the refrigerant that has come from the ejector 3, and is separated into a gas phase and a liquid phase in the gas-liquid separator 4, the gas phase being the compressor 1 and the liquid phase being the refrigerant evaporator. Up to 6.

As described above, the bypass flow path B for allowing a part of the refrigerant discharged from the refrigerant radiator 2 to bypass the ejector 3 and flow into the gas-liquid separator 4 is provided, and in the middle of the bypass flow path B. The control valve 7 is provided so that when the refrigerant discharged from the refrigerant radiator 2 has a predetermined pressure condition, the control valve 7 is opened to allow the refrigerant to flow into the bypass flow passage B.

This is because when the refrigerant flow rate increases and the refrigerant pressure on the high-pressure side becomes unnecessarily high, a part of the high-pressure refrigerant is branched so as to bypass the ejector 3 and flow. It is to avoid pressure rise. As a result, it is possible to reliably prevent the refrigerant pressure from rising too high, and to operate the refrigeration cycle in a stable manner. Further, even when the refrigerant flow rate increases, the increase in power of the refrigerant compressor 1 is suppressed and the cycle efficiency is improved.

The liquid refrigerant that has passed through the bypass flow path B flows through the refrigerant evaporator 6 as described above together with the liquid refrigerant that has passed through the ejector 3 to exert the effect of cooling. Therefore, when a large cooling capacity is required as in the case of cool down, the flow rate of the refrigerant flowing through the refrigerant evaporator 6 can be increased by flowing the refrigerant through the bypass flow path B, so that a larger cooling capacity can be obtained. .

(Second Embodiment) FIG. 4 is a schematic diagram of an ejector cycle according to a second embodiment of the present invention. The configuration of the refrigerant flow passage on the refrigerant evaporator 6 side and the connection destination of the bypass flow passage B are different from those of the first embodiment. As a configuration of the refrigerant flow path on the refrigerant evaporator 6 side, 5 is a flow rate control valve for adjusting the flow rate of the refrigerant flowing through the refrigerant evaporator 6, and the superheat degree detecting means 5a detects the degree of refrigerant superheat at the outlet of the refrigerant evaporator 6. The superheat degree is controlled so as to reach a predetermined value. Also, the bypass flow path B
Is connected to the gas-liquid separator 4 in the first embodiment,
A portion C is provided between the flow control valve 5 and the refrigerant evaporator 6 described above.

Next, the operation of the refrigeration cycle will be described. When the high pressure side refrigerant pressure exceeds the opening pressure of the control valve 7, the control valve 7
Is opened, and the gas-liquid two-phase refrigerant whose pressure has been reduced by the control valve 7 flows through the bypass passage B. The refrigerant from the bypass flow path B flows into the portion C, is mixed with the low-pressure refrigerant whose pressure is reduced by the flow control valve 5, flows through the refrigerant evaporator 6, is sucked by the ejector 3, and is mixed with the nozzle jet flow to be pressurized, It reaches the gas-liquid separator 4.

In this way, a part of the refrigerant flowing out of the refrigerant radiator 2 bypasses the ejector 3, the gas-liquid separator 4 and the flow rate control valve 5 and flows into the refrigerant evaporator 6, which is a bypass passage B.
And the control valve 7 is provided in the middle of the bypass flow path B.
The control valve 7 is opened to allow the refrigerant to flow into the bypass passage B when the refrigerant discharged from the refrigerant radiator 2 has a predetermined pressure condition.

Also in this case, when the refrigerant flow rate increases and the refrigerant pressure on the high-pressure side becomes unnecessarily high, a part of the high-pressure refrigerant is branched and the ejector 3 is bypassed to flow the pressure on the high-pressure side. It is to avoid rising.

A flow rate adjusting valve 5 may be provided in the refrigerant flow path B on the side of the refrigerant evaporator 6, and even if a part of the high pressure refrigerant is branched so as to bypass the ejector 3 and flow. It is possible that the flow rate of the refrigerant is reduced and the increase in pressure on the high-pressure side cannot be avoided as expected. In the case of the present embodiment, since the flow rate control valve 5 is also bypassed and the refrigerant is allowed to flow into the refrigerant evaporator 6, it is possible to reliably prevent the refrigerant pressure from rising too high, and to operate the refrigeration cycle stably. In addition, even when the refrigerant flow rate increases, the increase in power of the refrigerant compressor 1 is suppressed, and the cycle efficiency is improved.

The ejector 3 is also used in this embodiment.
When the refrigerant that bypassed is passing through the refrigerant evaporator 6,
Since the cooling effect is exerted together with the liquid refrigerant from the gas-liquid separator 4, when a large cooling capacity is required such as during cool down, the flow rate through the refrigerant evaporator 6 can be increased as compared with the conventional one, so that a larger cooling capacity can be obtained. Can be obtained.

(Third Embodiment) FIG. 5 is a schematic diagram of an ejector cycle according to a third embodiment of the present invention. In this embodiment, an internal heat exchanger 8 is added to the cycle of the first embodiment to exchange heat between the refrigerant sucked into the refrigerant compressor 1 and the refrigerant discharged from the refrigerant radiator 2.

The internal heat exchanger 8 is formed by joining pressed aluminum plates by brazing, and a flow path 8a through which the refrigerant drawn into the refrigerant compressor 1 flows and a flow through which the refrigerant exiting the refrigerant radiator 2 flows. It is configured so as to flow opposite to the passage 8b and is used as a means for improving the cooling capacity and COP.

FIG. 6 is a sectional structural view of a control valve 70 applied to the present ejector cycle. In order to make the temperature sensing portion of the control valve 70 (the closed space 79 surrounded by the diaphragm 72 and the upper case 73) sense the temperature of the refrigerant that has exited the refrigerant radiator 2, the refrigerant flow path A1 flowing over the surface of the upper case 73.
And the flow path A2 → A3 on the valve body 71 side is partitioned by the partition part 86, and the heat insulating layer 8 made of resin is formed on the outer surface of the lower cover 74.
7 is provided to make it difficult for the heat of the refrigerant A2 after passing through the internal heat exchanger 7 to be transferred to the diaphragm 72 side.

Next, the operation of the refrigeration cycle will be described. The refrigerant discharged from the refrigerant radiator 2 passes through the flow path A1 of the control valve 70, is cooled by the low temperature refrigerant sucked into the refrigerant compressor 1 in the internal heat exchanger 8, and is cooled. After that, the control valve 7
It passes through the flow paths A2 → A3 in 0 and flows into the ejector 3. The operation of the control valve 70 is the same as that of the first embodiment, and when the high-pressure side refrigerant pressure exceeds the valve opening pressure of the control valve 70, the valve opens and the refrigerant flows in the bypass flow path b. Sometimes the valve is closed.

As described above, including the first embodiment, the control valves 7 and 70 form a part of the refrigerant flow path A from the refrigerant radiator 2 to the ejector 3, and the refrigerant flow path A to the bypass flow path. A diaphragm (displacement member) 72 having a valve port 76 communicating with b, forming a sealed space 79 in which a refrigerant gas is sealed at a predetermined density in a refrigerant flow path A, and displacing in accordance with a pressure difference between the inside and outside of the sealed space 79. And its diaphragm 72
And a valve body 71 that opens and closes the valve port 76 in cooperation with the valve body 76, and the diaphragm 72 is displaced to open the valve port 76 when the internal pressure of the refrigerant passage A exceeds the internal pressure of the sealed space 79.

When the internal pressure of the refrigerant passage A on the high pressure side is equal to or lower than the internal pressure of the closed space 79 which is a predetermined pressure, all the refrigerant exiting the radiator 2 passes through the ejector 3.
When the internal pressure of the refrigerant flow path A on the high pressure side exceeds the internal pressure of the closed space 79 that is a predetermined pressure, a part of the high pressure refrigerant flows in the bypass flow path b, so that the high pressure rise due to the increase in the refrigerant flow rate is avoided. be able to.

Further, since the pressure in the closed space 79 of the control valves 7 and 70 changes according to the temperature of the high pressure refrigerant flowing out of the radiator 2, the opening pressure of the control valves 7 and 70 also changes according to the temperature of the high pressure refrigerant. Since the valve opening pressure changes and the valve opening pressure substantially coincides with the optimum control line that maximizes COP (coefficient of performance of the refrigeration cycle), the cycle operation can be controlled under the condition of high COP.

(Fourth Embodiment) FIG. 7 is a schematic diagram of an ejector cycle according to a fourth embodiment of the present invention.

The structure of the control valve 9 is different from that of the first embodiment. FIG. 8 is a sectional structural view of a control valve (differential pressure valve) 9 applied to the present ejector cycle.

Reference numeral 91 is stainless steel, brass or the like having an inflow port 92 communicating with a branch F provided in a refrigerant flow path A connecting the refrigerant radiator 2 and the ejector 3 and an outflow port 95 communicating with the gas-liquid separator 4. The housing 91 is made of a metal, and a valve port 93 is formed in the housing 91 to connect the space on the inflow port 92 side with the space on the outflow port 95 side. Also,
A valve body 96 for adjusting the opening degree of the valve port 93 is arranged in the space on the outflow port 95 side, and the valve body 96 is provided on the inflow port 92 side by a metallic coil spring (elastic member) 97. Pressed towards the space.

The housing 91 includes a lid member 94 in which an outflow port 95 is formed and an inflow port 9 of the housing 91.
2 is formed and a cylindrical main body portion, and the bottom portion and the main body portion are integrally molded. The lid member 94 includes the valve body 96 and the coil spring 97 in the housing 91. After being stored in the housing 91, it is connected to the housing 91 by a connecting means such as welding or screw connection.

Further, 98 is the valve body 9 in the housing 91.
It is a guide skirt that guides the movement of 6 (guide),
The cylindrical outer peripheral surface of the guide skirt 98 is the housing 91.
The movement of the valve body 96 is guided by contacting the inner wall of the valve. Further, in the vicinity of the valve body 96 of the guide skirt 98, a plurality of holes 99 forming a flow path of CO ₂ are formed.

Next, the operation of the differential pressure regulating valve 9 will be described. As is apparent from FIG. 8, the acting force F1 due to the outlet side pressure of the refrigerant radiator 2 acts on the inflow port 92 side of the valve body 96, so that the valve body 96 is pressed toward the outflow port 95 side. On the other hand, on the outlet 95 side, the pressure inside the gas-liquid separator 4 and the coil spring 9 are increased.
Since the force F2 due to the elastic force of 7 acts, the valve body 96 is pressed toward the inflow port 92 side.

That is, when the acting force F2 is larger than the acting force F1, the valve body 96 closes the valve opening 93 and the refrigerant does not flow into the bypass flow passage b. When the acting force F2 is less than the acting F1, the valve body is closed. 96 is pushed and moved by the acting force F1, the valve port 93 is opened, and the refrigerant flows in the bypass flow path b. Therefore, the valve opening differential pressure ΔP of the differential pressure valve 9 corresponds to the elastic force exerted on the valve body 96 by the coil spring 97.

For example, FIG. 9 is a graph showing an example of the operating characteristics of the differential pressure valve 9. When the valve opening differential pressure of the differential pressure valve 9 is set to 8 MPa, the cooling load is large and the pressure 6 in the gas-liquid separator 4 is increased.
When the pressure is MPa, the high pressure side opens at 14 MPa, and when the cooling load is small and the pressure inside the gas-liquid separator 4 is 4 MPa, the high pressure side is
The valve will open at 12 MPa. (Assuming that the pressure increase amount of the ejector 3 is 0.5 MPa, the evaporator pressure is 5.5 MPa and the evaporator temperature is 18 ° C. when the load is large, and the evaporator pressure is 3.5 MPa and the evaporator temperature is 0 ° C. when the load is small. In this way, in the control valve 9, the pressure of the refrigerant leaving the refrigerant radiator 2 on the upstream side of the valve is the refrigerant pressure in the gas-liquid separator 4 on the downstream side of the valve, or the refrigerant evaporator 6 The valve opens when the pressure difference exceeds a predetermined pressure difference with respect to the refrigerant pressure.

The control valve 9 of this embodiment is a differential pressure valve 9 that opens when the differential pressure across the valve exceeds a predetermined value. By using the differential pressure valve 9, when the cooling load is large and the internal pressure of the refrigerant evaporator 6 is high, that is, when the internal pressure of the gas-liquid separator 4 is also high, the refrigerant pressure bypassing the ejector 3 is high, and the cooling air is cooled. When the load is small and the internal pressure of the refrigerant evaporator 6 is low, that is, the internal pressure of the gas-liquid separator 4 is also low, the refrigerant pressure bypassing the ejector 3 can be controlled to be low.

[0062] When the CO ₂ cycle using CO ₂ to the refrigerant, when the outlet refrigerant temperature of the refrigerant radiator 2 are the same, since the refrigerant pressure increases contributes enthalpy difference in the cooling higher, when the load of cooling large The pressure for opening the differential pressure valve 9 increases and the cooling capacity also increases. When the cooling load is small, the pressure for opening the differential pressure valve 9 decreases and the cooling capacity also decreases, increasing the power of the compressor 1. CO is suppressed
The decrease in P is also suppressed.

(Fifth Embodiment) FIG. 10 shows the fifth embodiment of the present invention.
It is a schematic diagram of an ejector cycle in the embodiment,
FIG. 11 is a sectional structural view of an ejector / differential pressure valve integrated gas-liquid separator 40 applied to the present ejector cycle. Four
1, 42 are housings of the gas-liquid separator, and in this embodiment, the ejector 3 and the differential pressure regulating valve 9 in the fourth embodiment are integrated with the housing 42, whereby the bypass flow passage b is unnecessary. The differential pressure valve 9 has the same structure as that of the fourth embodiment and operates in the same way.

43 is a high pressure side inlet into which the high pressure refrigerant flows,
Reference numeral 44 denotes a high pressure side inflow chamber for branching the refrigerant to the nozzle 31 side and the differential pressure valve 9 and is formed by assembling the inflow port block 45 to the housing 42. Reference numeral 32 is a low-pressure side inlet into which the low-pressure refrigerant from the refrigerant evaporator 6 flows, 50 is a vapor-phase refrigerant outlet, and 51 is a liquid-phase refrigerant outlet. The differential pressure valve 9 has the same structure as that of the fourth embodiment.

The high-pressure refrigerant having entered from the high-pressure side inlet 43 flows into the nozzle 31, and the ejector housing 36 made of metal.
It flows out of the ejector housing 36 through the mixing portion 33 and the diffuser 34 formed inside. Then, it passes through a resin-made cylinder 46 whose one end is closed, and blows into the upper space of the gas-liquid separator 40 above the resin partition plate 47.

Then, it passes through a passage 47a provided on the outer periphery of the partition plate 47 and enters the space below the partition plate 47. Then, the liquid phase is stored on the lower side by gravity and the gas phase is stored on the upper side. The vapor phase flows out of the vapor phase outlet 50 through the resin vapor phase introducing pipes 48 and 49, and the liquid refrigerant flows out of the liquid refrigerant outlet port 51.

The partition plate 47 prevents the gas-liquid mixed refrigerant flowing into the gas-liquid separator 4 from directly entering the inflow port 48a of the gas-phase introducing pipe 48, and efficiently separates it into a gas phase and a liquid phase. It was installed in. 48b is an oil return port for returning the refrigerating machine oil for lubrication to the compressor 1 together with the refrigerant.

In this way, the gas-liquid separator 4 has the ejector 3 and the differential pressure valve 9 built-in or integrated therein, which reduces the number of parts as a whole and facilitates processing and assembly. In addition, the apparatus becomes compact and the number of pipelines connecting the various equipments such as the pipeline of the bypass flow path b can be reduced, so that the mountability and the assemblability on the vehicle etc. are improved.

(Other Embodiments) The present invention is not limited to the above-described embodiments, but can be modified or expanded as follows. Although the refrigeration cycle using carbon dioxide as the refrigerant has been described in the above embodiment, the present invention may be applied to a refrigeration cycle using freon as the refrigerant. Further, as the control valve, in addition to the mechanically operated one as in the present embodiment, an electrically operated one such as a conventionally known electric expansion valve having a fully closing function. May be used.

Incidentally, the connection destination of the bypass flow passage b in the third and fourth embodiments may be just before the refrigerant evaporator 6 as in the second embodiment. In addition, in the first and third to fifth embodiments, as the configuration of the refrigerant flow path on the refrigerant evaporator 6 side, the second
Like the embodiment, the gas-liquid separator 4 (40) and the refrigerant evaporator 6
A flow rate control valve 5 for adjusting the flow rate of the refrigerant may be provided between and. The flow control valve in this case may be the same superheat control valve as in the second embodiment or may be a fixed throttle valve.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an ejector cycle according to a first embodiment of the present invention.

FIG. 2 is a sectional structural view of a control valve applied to the ejector cycle of FIG.

FIG. 3 is a Mollier diagram of CO ₂ .

FIG. 4 is a schematic diagram of an ejector cycle according to a second embodiment of the present invention.

FIG. 5 is a schematic diagram of an ejector cycle according to a third embodiment of the present invention.

FIG. 6 is a sectional structural view of a control valve applied to the ejector cycle of FIG.

FIG. 7 is a schematic diagram of an ejector cycle according to a fourth embodiment of the present invention.

8 is a sectional structural view of a differential pressure valve applied to the ejector cycle of FIG.

FIG. 9 is a graph showing an example of operating characteristics of a differential pressure valve.

FIG. 10 is a schematic diagram of an ejector cycle according to a fifth embodiment of the present invention.

11 is a cross-sectional structural diagram of an ejector / differential pressure valve integrated gas-liquid separator applied to the ejector cycle of FIG.

FIG. 12 is a schematic diagram of a conventional ejector cycle.

FIG. 13 is a sectional structural view of an ejector.

[Explanation of symbols]

1 Refrigerant compressor 2 Refrigerant radiator 3 ejectors 4 gas-liquid separator 5 Flow control valve 6 Refrigerant evaporator 7 control valve 9 Differential pressure valve (control valve) 32 Suction section 70 Control valve 71 Disc 72 Diaphragm (displacement member) 76 valve 79 enclosed space A refrigerant flow path b Bypass channel

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // F16K 31/68 F16K 31/68 R (72) Inventor Tadatoshi Hotta 14 Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Prefecture Japan Auto Parts Research Institute, Inc. (72) Inventor Yuuji Takeuchi 1-1, Showa-cho, Kariya, Aichi Prefecture DENSO (72) Inventor, Hiroshi Ishikawa 1-1, Showa-cho, Kariya City, Aichi Stock Association F term in company DENSO (reference) 3H057 AA02 BB25 CC13 DD05 EE02 FA22 HH07 HH18

Claims (5)

[Claims] 1. A refrigerant compressor (1), a refrigerant radiator (2),
The ejector (3) and the gas-liquid separator (4) are annularly connected by the refrigerant channel (A), and the gas-liquid separator (4) is also connected.
Liquid-phase refrigerant side and the suction part (32) of the ejector (3)
In a refrigeration cycle apparatus in which a refrigerant flow path is connected to a refrigerant evaporator, and a refrigerant evaporator (6) is provided in the refrigerant flow path, a part of the refrigerant discharged from the refrigerant radiator (2) is part of the ejector (3). ) Is bypassed to flow into the gas-liquid separator (4), and a control valve (7, 70, 9) is provided in the middle of the bypass flow channel (B).
The control valve (7, 70, 9) is opened to allow the refrigerant to flow into the bypass passage (B) when the refrigerant discharged from the refrigerant radiator (2) has a predetermined pressure condition. A characteristic refrigeration cycle device. 2. A refrigerant compressor (1), a refrigerant radiator (2),
The ejector (3) and the gas-liquid separator (4) are annularly connected by the refrigerant channel (A), and the gas-liquid separator (4) is also connected.
Liquid-phase refrigerant side and the suction part (32) of the ejector (3)
Are connected by a refrigerant flow path, and the refrigerant flow path is provided with a refrigerant evaporator (6) and a flow rate control valve (5) for adjusting the amount of the refrigerant flowing into the refrigerant evaporator (6) and reducing the pressure. In the refrigeration cycle apparatus, a part of the refrigerant discharged from the refrigerant radiator (2) bypasses the ejector (3), the gas-liquid separator (4) and the flow rate control valve (5) to the refrigerant. A bypass flow passage (B) for flowing into the evaporator (6) is provided, and a control valve (7, 70, 9) is provided in the middle of the bypass flow passage (B) to exit the refrigerant radiator (2). A refrigeration cycle apparatus, wherein the control valve (7, 70, 9) is opened to allow the refrigerant to flow into the bypass passage (B) when the refrigerant has a predetermined pressure condition. 3. The control valve (7, 70) forms a part of a refrigerant passage (A) from the refrigerant radiator (2) to the ejector (3), and the refrigerant passage (A). ) To the bypass flow path (B), a closed space (79) is formed in the refrigerant flow path (A) in which a refrigerant gas is filled at a predetermined density, and the closed space ( 79)
The refrigerant flow path (A) includes a displacement member (72) that is displaced according to a pressure difference between the inside and the outside, and a valve body (71) that opens and closes the valve opening (76) in conjunction with the displacement member (72). 3.) When the internal pressure exceeds the internal pressure of the closed space (79), the displacement member (72) is displaced to open the valve opening (76). The refrigeration cycle apparatus according to 1. 4. The control valve (9) is provided in the gas-liquid separator (4) where the pressure of the refrigerant leaving the refrigerant radiator (2) on the upstream side of the valve is on the downstream side of the valve. The refrigeration cycle according to claim 1 or 2, wherein the valve is opened when a predetermined pressure difference with respect to the refrigerant pressure or the refrigerant pressure in the refrigerant evaporator (6) is exceeded. apparatus. 5. The refrigeration cycle apparatus according to claim 4, wherein the gas-liquid separator (4) has the ejector (6) and the control valve (9) built-in or integrated with each other.