JP3291886B2 - Air conditioner and control method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly to an air conditioner mounted on a vehicle.

[0002]

2. Description of the Related Art Conventionally, in an air conditioner mounted on a vehicle, a hot water heater utilizing cooling hot water of an internal combustion engine mounted on the vehicle has been used, and this hot water heater is used as a main heating device. However, with this hot water heater alone, sufficient heating capacity cannot be obtained because the temperature of the cooling water is low when the internal combustion engine is started.

[0003] For this reason, there is an apparatus that uses an auxiliary heating apparatus that supplements the main heating apparatus to improve the heating capacity when the internal combustion engine starts up. As this auxiliary heating device,
Electric heaters, combustion heaters, heat pumps and the like are used.

[0004]

However, in such a heating apparatus using an electric heater, a combustion heater, and a heat pump in combination as an auxiliary heating apparatus in addition to the main heating apparatus, for example, when the electric heater is used in combination with the electric heater, the electric power of the vehicle is reduced. There is a problem that the shortage is likely to occur, the one using the combustion heater together has a problem that the safety tends to deteriorate, and the one using the heat pump also has a problem that it cannot be used in cold regions.

[0005] In order to solve such a problem, in addition to a main heating device such as a hot water heater, a vehicular auxiliary for improving heating capacity by using a high-temperature and high-pressure gas refrigerant (hot gas) in a refrigeration cycle. A heating device is conceivable. This auxiliary heating device for a vehicle can perform a heating cycle operation only by adding a small number of pipes to pipes constituting a cooling cycle and switching a refrigerant flow path.

[0006] However, in this hot gas heater cycle, no effective method has been known for controlling the extremely small amount of refrigerant although the required amount of refrigerant is extremely small. For example, when the hot gas heater cycle operation is performed with the refrigerant amount during the cooling cycle,
When the temperature is low, the refrigerant becomes excessive and the compressor may be damaged by the liquid returning to the compressor, and when the temperature is high, the pressure becomes abnormally high and the hot gas heater cycle may stop.

The present invention has been made to solve such a problem, and an object of the present invention is to provide an air conditioner that appropriately controls a refrigerant flow rate in the hot gas heater cycle. Another object of the present invention is to provide a control amount control system that prevents an abnormal state such as a high pressure abnormality, a shortage of refrigerant, and an excess refrigerant in the hot gas heater cycle and appropriately controls the refrigerant amount. .

[0008]

To achieve the above object, an air conditioner according to the present invention has a refrigerant compressor (2) for compressing a refrigerant into a high-temperature and high-pressure gas refrigerant.
A condenser (3) connected to the discharge side of the refrigerant compressor (2) and condensing the gas refrigerant compressed by the refrigerant compressor (2)
First decompression means (5) for decompressing the refrigerant condensed in the condenser (3); a discharge side of the first decompression means (5); and a suction side of the refrigerant compressor (2). A first control valve (9) provided on a path connecting the refrigerant compressor (2) and the condenser (3), and opening and closing this path; A first connecting the inlet side of the first control valve (9) and the outlet side of the first pressure reducing means (5), bypassing the condenser (3) and the first pressure reducing means (5);
, A second decompression means (11) provided in the middle of the first bypass flow path (8) for decompressing the flowing refrigerant, and the first bypass flow path (8) A second control valve (10) provided in the middle of the first control valve (10) for opening and closing the first bypass flow path (8); and the first control valve (9).
A second bypass flow path (28) connecting the inlet side of the first pressure reducing means (5) to the inlet side of the first decompression means (5), and provided in the second bypass flow path (28); Road (8)
A refrigerant state detecting means (14) which is opened when the internal pressure is higher than a predetermined pressure, and is closed when the pressure in the first bypass flow path (8) is lower than a predetermined pressure; ) And an outlet side of the heat exchanger (6), and a third bypass passage (29) provided in the middle of the third bypass passage (29), and opened when the refrigerant is insufficient. A configuration characterized by including the third control valve (7) is employed.

Here, the refrigerant state detecting means is means for detecting the state of the refrigerant and controlling the state of the refrigerant, and the "state" refers to the state of the refrigerant such as pressure, temperature, volume, density, and component ratio. In the refrigerant state detection means, the detection unit for detecting the state of the refrigerant and the control unit for controlling the state of the refrigerant may be integrated or separate. The detection unit that detects the state of the refrigerant includes, for example, a pressure sensor and a pressure switch as pressure detection means, and includes, for example, a temperature sensor and a temperature switch as temperature detection means. The control unit that controls the state of the refrigerant includes a mechanical pressure relief valve, a solenoid valve, and the like as pressure regulating valves.

[0010]

According to the air conditioner of the present invention having the above structure,
During cooling, the control means opens the first control valve and closes the second control valve to form a cooling cycle including the compressor, the condenser, the first pressure reducing means, and the heat exchanger.
Therefore, the high-temperature and high-pressure refrigerant discharged from the compressor flows into the condenser and is condensed, and the refrigerant condensed in this condenser is depressurized by the first decompression means. This depressurized refrigerant is
It flows into the heat exchanger and exchanges heat with external air to cool the air.

On the other hand, at the time of heating, the control means closes the first control valve and opens the second control valve to form a heating cycle including the compressor, the second pressure reducing means, and the heat exchanger. I do. Accordingly, the high-temperature and high-pressure refrigerant discharged from the compressor flows into the first bypass flow path, is decompressed by the second pressure reducing means provided in the middle of the first bypass flow path, and flows into the heat exchanger. I do. The refrigerant flowing into the heat exchanger is radiated by exchanging heat with an airflow flowing outside the heat exchanger, and is heated by the heat-exchanged airflow.

At the time of this heating, if the refrigerant is excessive,
When the pressure in the heating cycle becomes higher than a predetermined pressure, the pressure state detecting means provided in the second bypass flow path is opened, and the refrigerant in the heating cycle is supplied to the first control valve and the first pressure reducing means. Into the flow path between. When the amount of charged refrigerant is insufficient, the first control valve is closed, the second control valve and the third control valve are opened, and the refrigerant stored in the condenser is supplied to the hot gas refrigerant circuit. Thereby, the amount of refrigerant in the hot gas refrigerant circuit is maintained at an appropriate amount.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the air conditioner of the present invention is applied to an air conditioner for a vehicle will be described below with reference to the drawings. (First Embodiment) FIGS. 1 to 5 show a first embodiment of the present invention.

FIG. 1 is a diagram showing a refrigeration cycle of the present invention, FIG. 4 is a Mollier diagram showing a state in the refrigeration cycle, and FIG. 5 is a diagram showing a gas release mechanism which is a main part of the present invention. FIG. The refrigeration cycle of the present invention includes a compressor (compressor) 2 driven by a sub engine 1.
A refrigeration cycle including a condenser (condenser) 3, a receiver 4, a supercooler 16, an expansion valve 5, and an evaporator 6 is connected by a pipe 20. An electromagnetic valve (corresponding to a first control valve of the present invention) 9 is provided in the middle of a pipe 20 connecting the compressor 2 and the condenser 3, and the expansion valve 5 is connected to the pipe 20 between the compressor 2 and the electromagnetic valve 9.
A first bypass flow path 8 is provided in the middle of a pipe 20 connecting the evaporator 6 and the evaporator 6. An electromagnetic valve (corresponding to a second control valve of the present invention) 10 and a decompression device 11 composed of a fixed throttle are provided in the middle of the first bypass passage 8. An accumulator 12 is provided between the evaporator 6 and the inlet of the compressor 2. The outlet of the pressure relief valve 14 (corresponding to the refrigerant state detecting means or the pressure control means of the present invention) is connected to the accumulator 12 and the compressor 2 by a third bypass flow path. An electromagnetic valve (corresponding to a third control valve of the present invention) 7 is provided in the third bypass passage 29. Furthermore, between the expansion valve 5 and the evaporator 6,
A check valve 13 is provided to prevent the refrigerant from flowing back from the evaporator 6 to the expansion valve 5 and the super cooler 16.

The compressor 2 corresponds to the refrigerant compressor of the present invention, and compresses the refrigerant flowing in the refrigeration cycle into a high-temperature and high-pressure gas refrigerant. The condenser 3 corresponds to the condenser of the present invention, in which a gas refrigerant having a high temperature and a high pressure flows in the compressor 2 and exchanges heat with external air to condense the refrigerant. In the receiver 4, the refrigerant flowing from the condenser 3 flows, and only the liquid refrigerant flows into the super cooler 16.

The supercooler 16 supercools the high-pressure liquid refrigerant flowing from the receiver 4. The expansion valve 5 corresponds to the first decompression means of the present invention, and decompresses the high-pressure liquid refrigerant flowing from the supercooler 16 into a low-temperature and low-pressure mist-like refrigerant. The evaporator 16 is equivalent to the heat exchanger of the present invention, in which a mist-like refrigerant having a low temperature and a low pressure flows in at the expansion valve 5 and exchanges heat with the outside air to cool the air. The refrigerant is a gaseous refrigerant.

As shown in the detailed view of FIG. 5, the pressure relief valve 14 is provided with a bottomed cylindrical portion 213 so as to form a T-shaped path in the second bypass passage 28. Also,
A plate 211 that closes the second bypass flow path 28 is movably provided. The plate 211 has a spring 212 that presses the plate 211 downward with a predetermined pressing force.
Is provided.

The solenoid valves 9 and 10 are controlled to open and close by a control unit (not shown). This control unit opens the solenoid valve 9 and closes the solenoid valve 10 during cooling,
At the time of heating, the solenoid valve 10 is opened, and when the refrigerant is insufficient, the solenoid valve 9 is opened. Next, the operation of the above refrigeration cycle will be described. During cooling, the solenoid valve 9 is opened,
By closing the solenoid valve 10, a cooling cycle in which a refrigerant flows through a pipe 20 connecting the compressor 2, the condenser 3, the receiver 4, the supercooler 16, the expansion valve 5, and the evaporator 6 becomes a cooling cycle. It works as described.

On the other hand, at the time of heating, the solenoid valve 9 is closed and the solenoid valve 10 is opened, so that the refrigerant which has become high temperature and high pressure in the compressor 2 and flows out flows into the first bypass passage 8. This refrigerant is depressurized by the decompression device 11 and flows into the evaporator 6. The refrigerant flowing into the evaporator 6 is cooled by exchanging heat with external air.
At this time, the external air is heated by exchanging heat with the refrigerant. As described above, air can be heated as an auxiliary heating device by a cycle including the compressor 2, the pressure reducing device 11, and the evaporator 6 (hereinafter, referred to as a hot gas heater cycle).

Compressor 2 driven by sub-engine 1
Is discharged by the condenser 3 and the super cooler 16, expanded by the expansion valve 5, absorbed by the evaporator 6, and returned to the compressor 2 via the accumulator 12. In the cooling cycle, the first bypass passage 8 as a piping for a hot gas heater cycle is provided. The flow direction of the gas discharged from the compressor 2 is switched by solenoid valves 9 and 10. And the decompression device 11,
The addition of the check valve 13 constitutes a hot gas heater cycle.

In the hot gas heater cycle, it is necessary to control the amount of refrigerant in the shaded area shown in FIG. The reason is that in the refrigerant shortage area shown in FIG. 2, the required heating capacity cannot be obtained due to gas shortage, and in the refrigerant excess area, the excess refrigerant returns to the inside of the compressor as a liquid refrigerant, and the compressor may be damaged. Also, in the excess refrigerant region, an excessively high refrigerant results in an abnormally high pressure.

Next, the refrigerant amount control means will be described. In the refrigerant shortage region, the superheat is larger than in the optimum state. Therefore, the superheat amount is detected by the superheat switch 15 and the like, and the refrigerant gas is sucked from the existing solenoid valve 7 from the stop cycle. In the refrigerant surplus region, the refrigerant remains in the accumulator 12 provided in the low-pressure pipe as liquid refrigerant. Further, since the high pressure increases in the suction temperature high temperature range, the pressure can be released to the low pressure side cycle by providing the pressure relief valve 14 in the discharge pipe.

As shown in FIG. 5, for example, the pressure relief valve 14 is provided with a bottomed cylindrical portion 213 so as to form a T-shaped path in the second bypass flow path. Also the second
A plate 211 that forms the bypass flow path 28 is movably provided. The plate 211 is provided with a spring 212 that presses the plate 211 downward in the figure with a predetermined pressing force.

Since the spring 212 of the pressure relief valve 14 presses the plate 211 with a predetermined pressing force, when the pressure of the refrigerant in the first bypass passage 8 is lower than the predetermined pressure,
The plate 211 is in a state where the second bypass flow path 28 is closed. On the other hand, when the pressure of the refrigerant in the first bypass flow path 8 becomes equal to or higher than a predetermined pressure, the pressure overcomes the pressing force of the spring 212 and the plate 211 is pushed up, so that the first bypass flow path 8 and the second bypass flow path 28 communicates. Therefore, when the pressure of the refrigerant that has been increased by the compressor 12 exceeds a predetermined pressure, the pressure relief valve 14 is opened to remove the refrigerant, thereby avoiding an abnormally high pressure. Since this hot gas heater cycle is a cycle in which the bypass passages 8 and 28 are added to the above-described cooling cycle, the cooling cycle is stopped during the operation of the hot gas heater cycle. The heating operation can be continued by removing the refrigerant to the side.

The state of an abnormally high pressure will be described with reference to a Mollier diagram in FIG. As shown in FIG. 4, the above hot gas heater cycle draws a triangle. This triangle moves from state to state to state to state as the air suction temperature of air from the vehicle interior increases, and the pressure of the refrigerant increases. As described above, if the heating operation is continued while the pressure is gradually increased from the state to the state, the heating operation is stopped due to an abnormally high pressure as in the state. Therefore, as described above, the state shown by the dotted line is obtained by removing the refrigerant by the pressure relief valve 14, and thereafter, the heating operation is performed while maintaining the state so that the high pressure does not become abnormally high. Can be. At this time, the state gradually moves to the right side, and the heating operation is continued in a direction in which the degree of superheat SH (superheat) increases.

A specific example will be described based on the refrigerant behavior shown in FIG. (1) The amount of refrigerant in the refrigeration cycle is 0.5 kg
At this time, the liquid refrigerant is initially stored in the accumulator 12, but the superheat degree SH increases as the suction temperature increases, and when the superheat degree SH = b ° C., the solenoid valve 7 opens to suck the refrigerant. . When the refrigerant is drawn in, the degree of superheat SH becomes small, and when SH = a ° C., the solenoid valve 7 is closed. The same is repeated several times, and when the high pressure increases, the pressure relief valve 14 operates to maintain the pressure below the abnormally high pressure.
(2) When the refrigerant amount is 1.0 kg, the refrigerant amount is initially 0.5
The refrigerant is stored in the accumulator 12 as in the case of kg, but when the degree of superheat SH = b, the solenoid valve 7 opens and the refrigerant is sucked. When the superheat degree SH = a, the electromagnetic valve 7
Closes. Thereafter, even if the intake air temperature rises, the refrigerant amount falls within the control range, and the operation can be continued with the refrigerant amount as it is.

As a modification of the first embodiment, in the state of the refrigerant surplus region, the superheat degree SH is equal to or less than zero. May be released. Further, in the state of the refrigerant surplus region, a pressure switch or the like may be provided on the discharge pipe side, and the refrigerant may be discharged from the solenoid valve 9. Second Embodiment As shown in FIG. 6, the second embodiment of the present invention has the same basic structure as the first embodiment shown in FIG. 1, but in addition to this structure, the second embodiment Is the bypass passage 3
1 is provided. In this case, since the suction temperature is high when the discharge pressure of the compressor 2 is abnormally high, the abnormal high pressure can be avoided by bypassing the intake pipe to the suction side.

(Third Embodiment) FIG. 7 shows a third embodiment of the present invention.
10 to FIG. The refrigerant circuit according to the third embodiment is basically the same as the refrigerant circuit of the first embodiment, and therefore, different parts will be described. An electromagnetic valve 114 is provided in the first bypass passage 28 instead of the pressure relief valve 14. A pressure switch 116 is provided in the flow path on the outlet side of the compressor 2. Then, the refrigerant flow during the hot gas heater cycle operation returns from the compressor 2 to the inlet side of the compressor 2 via the solenoid valve 10, the pressure reducing device 11, the evaporator 6, and the accumulator 12, as shown in FIG. Refrigerant circulates through this circuit.

The following methods (1) and (2) can be used to solve the shortage of the refrigerant during the operation of the hot gas heater cycle. (1) Refrigerant Replenishment from Stopping Cycle The method of resolving the shortage of the refrigerant is to open the electromagnetic valve 7 so that the refrigerant lying in the receiver 4
And supply to the inlet side of the compressor 2. This method is the same as that of the refrigerant supply described in the first embodiment.

(2) Execution of the cooling cycle operation at the beginning of the heating operation At the beginning of the heating operation, the cooling cycle operation is executed and the refrigerant lying in the receiver 4 is cooled by the expansion valve 5 and the check valve 13.
And supply it to the evaporator 6 which is one of the components constituting the hot gas heater cycle. In this method, when it is determined that the refrigerant is insufficient when the heating cycle switch is turned on, the solenoid valve 9 is opened and the solenoid valve 10 is closed for several seconds at the beginning of the heating operation, for example, so that the stop-side cycle is started. This is a method of sucking the sleeping refrigerant into the hot gas heater cycle via the check valve 13. In this method, a cooling cycle is operated for a few seconds in advance before a normal hot gas heater cycle is executed, so that the refrigerant discharged from the compressor 2 is supplied to the solenoid valve 9, the condenser 3, the receiver 4, the super cooler 16,
The gas flows into the compressor 2 via the expansion valve 5, the check valve 13, the evaporator 6, and the accumulator 12. After a few seconds of operation in this cooling cycle, the solenoid valve 9 is closed and the solenoid valve 10 is opened to eliminate the shortage of refrigerant in the hot gas heater cycle.

During the operation of the hot gas heater cycle, when the pressure switch 116 detects an abnormally high pressure, the solenoid valve 11
By opening the compressor 4, a part of the refrigerant discharged from the outlet side of the compressor 2 is discharged to the receiver 4 on the stop side. This discharge period is performed, for example, by opening the solenoid valve 114 for 2 seconds, for example, so that the discharge pressure of the compressor 2 becomes 25 at.
g to a compressor discharge pressure of 23 atg.

Next, in the third embodiment, an electric circuit block diagram for controlling each solenoid valve of the hot gas heater cycle is shown in FIG. 8, and a control flow thereof is shown in FIG. The signals input to the control circuit 30 are an ON / OFF signal of the heating cycle operation switch and an output signal of the pressure switch 116. The signal output from the control circuit 30 is a drive input signal to the solenoid valves 9, 10, and 114.

As shown in FIG. 9, at the time of the heating cycle operation in step 200, at the start of the operation, as shown in step 201, the cooling cycle is operated for several seconds with the blower stopped, for example, to secure the refrigerant in the hot gas heater cycle. Then, the process proceeds to step 202, where the solenoid valve 9 and the solenoid valve 114 are closed, and the solenoid valve 10 is opened. Thus, the operation of the hot gas heater cycle is started. Then step 2
In step 03, the rotation of the blower is started, and the air from the blower is sent to the evaporator 6 shown in FIG. As a result, a transition is made to the steady operation state in step 204. This steady operation state is a steady operation state in which a hot gas heater cycle is performed. When this system is applied to a vehicle air conditioner, the steady operation period is, for example, about 30 minutes. This steady operation period also changes depending on the intake air temperature.
Thereafter, in the vehicle air conditioner, main heating by the hot water heater is started.

Next, FIG. 10 shows an example of a control flow for appropriately coping with a shortage of refrigerant or an abnormally high pressure in the hot gas heater cycle. Steps 201, 202, 203 and 204 of the refrigerant amount control system flow shown in FIG. 10 are the same as the control flow shown in FIG. The cycle for replenishing the refrigerant when the refrigerant is insufficient is performed by switching the state of the solenoid valve 9 and the solenoid valve 10 shown in FIG. 11 from the closed state to the solenoid valve 9 closed and the solenoid valve 10 closed state. The pressure on the suction side 2 is reduced to a very low pressure close to vacuum. In this case, the suction side pressure of the compressor 2 is
The refrigerant which has become sufficiently small with respect to the pressure of the stop side cycle and stagnates in the stop side cycle is sucked into the hot gas heater cycle including the evaporator 6 and the like via the check valve 13.

Steps 205, 206, 207, 208
Shows a pressure drop control method when the pressure is abnormal. The discharge pressure Pd of the compressor 2 is detected by a pressure switch 116. The detection pressure of the pressure switch 116 is equal to the set value a.
(For example, a = 25 atg), that is, P
In the case of d <a, the routine proceeds from step 205 to step 204 to continue the steady operation state. In step 205, if the discharge pressure Pd of the compressor 2 is equal to or higher than the set value a, that is, if Pd ≧ a, the refrigerant discharged from the discharge side of the compressor 2 is opened by opening the solenoid valve 114 as shown in step 206. Is discharged to the stop cycle of the receiver 4 via the solenoid valve 114. Then, as shown in step 207, the compressor discharge pressure P
When d becomes smaller than a predetermined value b, that is, Pd <b
(B <a), when b = 20 atg, as shown in step 208, the solenoid valve 114 is closed to stop the discharge of the refrigerant to the stop side cycle, and as shown in step 204,
Continue steady operation. At this abnormally high pressure, the refrigerant amount control is repeatedly performed until heating of the hot gas heater cycle is completed.

According to the third embodiment, abnormal high pressure can be eliminated by controlling the solenoid valve 114 based on the pressure switch 116. When the refrigerant is insufficient, the cooling cycle is executed before the start of the hot gas heater cycle operation to circulate the refrigerant in the refrigerant circuit, thereby eliminating the refrigerant shortage. Also, as in the third embodiment, the pressure switch 116
Control circuit 30 when an abnormally high pressure is detected
By opening the solenoid valve 114 in response to the signal (1), the refrigerant is discharged to the stop-side cycle, whereby the abnormally high pressure can be eliminated.

In the third embodiment, the refrigerant state on the discharge side of the compressor 2 is detected by pressure.
The state of the refrigerant can be detected by temperature or the like, and the state of the refrigerant can be detected by temperature detecting means such as a temperature switch. By detecting the state of the refrigerant as temperature or the like, the solenoid valve 114 is detected.
Alternatively, the abnormal state of the refrigerant pressure can also be eliminated by controlling the opening and closing of a valve such as a pressure regulating valve corresponding to this.

(Fourth Embodiment) As another control example at the time of abnormally high pressure, as in the fourth embodiment shown in FIG.
The circuit without the pressure switch 116 shown in FIG. Description will be made using the refrigerant circuit shown in FIG. 11 without the pressure switch 116 shown in FIG. In this case, a pressure regulating valve 214 is used as shown in FIG. 11 instead of the electromagnetic valve 114 shown in FIG. This is because when the discharge pressure of the compressor 2 exceeds a (for example, a = 25 atg), the refrigerant discharged from the outlet side of the compressor 2 is discharged to the receiver 4 via the pressure control valve 214 by the pressure control valve 214. As a result, the compressor discharge side pressure is set to, for example, 23 atg.
It is a method of holding.

In the case of the fourth embodiment, the pressure regulating valve 214 shown in FIG. 11 is provided and the pressure switch 116 is not provided. In this case, when the discharge pressure of the compressor 2 reaches an abnormally high pressure, the pressure is regulated. By opening the valve 214 and discharging the refrigerant to the stop-side cycle via the pressure regulating valve 214, the proper refrigerant amount in the hot gas heater cycle can be maintained. In the fourth embodiment, since expensive equipment such as the pressure switch 116 and the valve corresponding to the solenoid valve 114 is not required, it is possible to eliminate the abnormally high pressure of the refrigerant by inexpensive means and to perform appropriate refrigerant amount control. effective.

[0040]

As described above, according to the air conditioner of the present invention, a simple heating device using a high-temperature and high-pressure gas refrigerant in the refrigerant circuit is constituted, and this heating device is added to the main heating device. Since the heating capacity is improved, rapid heating is possible. Further, according to the air conditioner of the present invention, the amount of refrigerant circulating in the circuit of the high-temperature and high-pressure gas refrigerant is controlled without excess or shortage, so that the heating capacity of the auxiliary heating device can be exhibited in a stable state, and the durability of the compressor is improved. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a refrigerant circuit of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a diagram showing required refrigerant amount characteristics.

FIG. 3 is a diagram showing a behavior of a refrigerant amount.

FIG. 4 is a partial Mollier chart showing a refrigeration cycle according to an embodiment of the present invention.

FIG. 5 is a sectional view of a pressure relief valve used in an embodiment of the present invention.

FIG. 6 is a circuit diagram showing a refrigerant circuit of an air conditioner according to a second embodiment of the present invention.

FIG. 7 is a circuit diagram illustrating a refrigerant circuit of an air conditioner according to a third embodiment of the present invention.

FIG. 8 is a system configuration diagram of a refrigerant amount control system according to a third embodiment of the present invention.

FIG. 9 is a flowchart showing a refrigerant shortage elimination flow at the beginning of a hot gas heater cycle operation according to a third embodiment of the present invention.

FIG. 10 is a flowchart showing a response to a shortage of refrigerant and abnormal pressure in a hot gas heater cycle according to a third embodiment of the present invention.

FIG. 11 is a circuit diagram showing a refrigerant circuit of an air conditioner according to a fourth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Sub engine 2 Compressor (refrigerant compressor) 3 Condenser (Condenser) 4 Receiver 5 Expansion valve (First decompression means) 6 Evaporator (Heat exchanger) 7 Solenoid valve (Third control valve) 8 First bypass Flow path 9 Solenoid valve (first control valve) 10 Solenoid valve (second control valve) 11 Second decompression device 14 Pressure relief valve (refrigerant state detection means, pressure control means) 28 Second bypass flow path 29 Third bypass flow path 114 solenoid valve 116 pressure switch (refrigerant state detecting means, pressure control means) 214 pressure regulating valve (refrigerant state detecting means, pressure control means)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F25B 1/00 B60H 1/03

Claims (5)

(57) [Claims] 1. A refrigerant compressor (2) that compresses a refrigerant into a high-temperature and high-pressure gas refrigerant, and is connected to a discharge side of the refrigerant compressor (2) and is compressed by the refrigerant compressor (2). Condenser for condensing gas refrigerant (3)
A first decompression means (5) for decompressing the refrigerant condensed in the condenser (3); a discharge side of the first decompression means (5) and a suction side of the refrigerant compressor (2). A first control valve (9) provided in a path connecting the refrigerant compressor (2) and the condenser (3) and connected to the heat exchanger (6), and opening and closing the path.
Bypassing the condenser (3) and the first pressure reducing means (5) and connecting an inlet side of the first control valve (9) and an outlet side of the first pressure reducing means (5). First bypass channel (8)
A second decompression means (11) provided in the middle of the first bypass flow path (8) to decompress the flowing refrigerant; and a second decompression means (11) provided in the middle of the first bypass flow path (8). The second control valve (1) for opening and closing the first bypass flow path (8)
0), a second bypass flow path (28) connecting the inlet side of the first control valve (9) and the inlet side of the first pressure reducing means (5).
And provided in the second bypass flow path (28).
Refrigerant state detection means (14) which opens when the pressure in the bypass flow path (8) is higher than a predetermined pressure and closes when the pressure in the first bypass flow path (8) is lower than a predetermined pressure.
A third bypass flow path (29) connecting the outlet side of the refrigerant state detecting means (14) and the outlet side of the heat exchanger (6); and a third bypass flow path (29) in the middle of the third bypass flow path (29). An air conditioner, comprising: a third control valve (7) provided and opened when the refrigerant is insufficient. 2. A refrigerant compressor (2) that compresses a refrigerant into a high-temperature and high-pressure gas refrigerant, and is connected to a discharge side of the refrigerant compressor (2) and compressed by the refrigerant compressor (2). Condenser for condensing gas refrigerant (3)
A first decompression means (5) for decompressing the refrigerant condensed in the condenser (3); a discharge side of the first decompression means (5) and a suction side of the refrigerant compressor (2). A first control valve (9) provided in a path connecting the refrigerant compressor (2) and the condenser (3) and connected to the heat exchanger (6), and opening and closing the path.
Bypassing the condenser (3) and the first pressure reducing means (5) and connecting an inlet side of the first control valve (9) and an outlet side of the first pressure reducing means (5). First bypass channel (8)
A second decompression means (11) provided in the middle of the first bypass flow path (8) to decompress the flowing refrigerant; and a second decompression means (11) provided in the middle of the first bypass flow path (8). The second control valve (1) for opening and closing the first bypass flow path (8)
0), a second bypass flow path (28) connecting the inlet side of the first control valve (9) and the inlet side of the first pressure reducing means (5).
And provided in the second bypass flow path (28).
A pressure control means (14) that opens when the pressure in the bypass flow path (8) is higher than a predetermined pressure and closes when the pressure in the first bypass flow path (8) is lower than or equal to a predetermined pressure; A third bypass flow path (29) connecting the outlet side of the pressure control means (14) and the outlet side of the heat exchanger (6); and a refrigerant provided in the middle of the third bypass flow path (29). An air conditioner comprising: a third control valve (7) that is opened when there is a shortage. 3. A refrigerant compressor (2) for compressing a refrigerant into a high-temperature and high-pressure gas refrigerant, and connected to a discharge side of the refrigerant compressor (2) and compressed by the refrigerant compressor (2). Condenser for condensing gas refrigerant (3)
A first decompression means (5) for decompressing the refrigerant condensed in the condenser (3); a discharge side of the first decompression means (5) and a suction side of the refrigerant compressor (2). A first control valve (9) provided in a path connecting the refrigerant compressor (2) and the condenser (3) and connected to the heat exchanger (6), and opening and closing the path.
Bypassing the condenser (3) and the first pressure reducing means (5) and connecting an inlet side of the first control valve (9) and an outlet side of the first pressure reducing means (5). First bypass channel (8)
A second decompression means (11) provided in the middle of the first bypass flow path (8) to decompress the flowing refrigerant; and a second decompression means (11) provided in the middle of the first bypass flow path (8). The second control valve (1) for opening and closing the first bypass flow path (8)
0), a second bypass flow path (28) connecting the inlet side of the first control valve (9) and the inlet side of the first pressure reducing means (5).
A pressure switch (116) for detecting a discharge side pressure of the refrigerant compressor (2); and a pressure switch (116) provided in the second bypass flow path (28). An electromagnetic valve (114) that opens when the pressure is high and closes when the pressure detected by the pressure switch (116) is equal to or lower than a predetermined pressure; an outlet side of the electromagnetic valve (114) and an outlet side of the heat exchanger (6) And a third control valve (7) provided in the middle of the third bypass flow path (29) and opened when the refrigerant is insufficient. Air conditioner. 4. The control method for an air conditioner according to claim 1, wherein the refrigerant discharged from the refrigerant compressor (2) at the time of a heating operation and at an initial stage is the condenser (3). Performing a cooling cycle that circulates a path returning to the refrigerant compressor (2) via the first pressure reducing means (5) and the heat exchanger (6);
Thereafter, the refrigerant discharged from the refrigerant compressor (2) is supplied to the second control valve (10) and the second pressure reducing valve (1).
1) A method for controlling an air conditioner that executes a hot gas heater cycle that circulates a path returning to the refrigerant compressor (2) via the heat exchanger (6). 5. The control method for an air conditioner according to claim 1, wherein the refrigerant discharged from the refrigerant compressor (2) at the time of a heating operation and at the initial stage is the condenser (3), Performing a cooling cycle that circulates a path returning to the refrigerant compressor (2) via the first pressure reducing means (5) and the heat exchanger (6);
Next, the refrigerant discharged from the refrigerant compressor (2) is supplied to the second control valve (10), the second pressure reducing valve (11),
A hot gas heater cycle that circulates a path returning to the refrigerant compressor (2) via the heat exchanger (6) is executed. During the operation of the hot gas heater cycle, the refrigerant on the discharge side of the refrigerant compressor (2) When the pressure is abnormally high, the refrigerant state detecting means (14, 1) is used until the refrigerant pressure during the hot gas heater cycle drops below a predetermined value.
(14) opening the refrigerant, and discharging the refrigerant in the hot gas heater cycle from the refrigerant state detecting means (14, 114) to the low pressure side stop cycle.