JP3303443B2 - Air conditioner - 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 a vehicle 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 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 using an auxiliary heating apparatus that supplements the main heating apparatus to improve the heating capacity when the internal combustion engine starts up. As the auxiliary heating device, an electric heater, a combustion heater, a heat pump 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, the electric power of a vehicle is not used in the case of using an electric heater in combination. There is a problem that shortage is apt to occur, and there is a problem that safety is likely to be reduced when a combustion heater is used together, and a problem that a heat pump is used together becomes impossible in a cold region.

Therefore, in order to solve such problems, in addition to a main heating device such as a hot water heater, an auxiliary vehicle for improving the heating capacity by using a high-temperature high-pressure gas refrigerant (hot gas) in a refrigeration cycle. A heating device is conceivable. However, in the above vehicle auxiliary heating device using the high-temperature and high-pressure gas refrigerant in the refrigeration cycle, during overload operation when the vehicle interior temperature is high, the pressure of the gas refrigerant discharged from the compressor becomes abnormally high, and the heating operation is performed. May stop.

Accordingly, an object of the present invention is to provide an air conditioner capable of maintaining a heating capacity while preventing the pressure in a refrigeration cycle from becoming abnormally high.

[0007]

In order to achieve the above object, the present invention provides a refrigerant compressor which compresses a refrigerant into a high-temperature and high-pressure gas refrigerant, and is connected to a discharge side of the refrigerant compressor.
A condenser for condensing the gas refrigerant compressed by the refrigerant compressor; a first decompression means for decompressing the refrigerant condensed in the condenser; a discharge side of the first decompression means and the refrigerant compressor A heat exchanger connected to the suction side of the first compressor, a first control valve provided on a path connecting the refrigerant compressor and the condenser, and opening and closing the path, the condenser and the first depressurization A first bypass flow path that bypasses the means and connects the inlet side of the first control valve and the outlet side of the first pressure reducing means, and a refrigerant that flows in the middle of the first bypass flow path A second decompression means for reducing the pressure, a second control valve provided in the middle of the first bypass flow passage, for opening and closing the first bypass flow passage, and a middle of the first bypass flow passage. A second bypass flow path connecting the first control valve and the first pressure reducing means; Provided in the second bypass passage,
A pressure control means that opens when the pressure in the first bypass flow path is higher than a predetermined pressure, and closes when the pressure in the first bypass flow path is lower than or equal to a predetermined pressure; Control means for opening the valve and closing the second control valve, and for heating, closing the first control valve and opening the second control valve during heating. It is.

[0008]

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. Accordingly, the high-temperature and high-pressure refrigerant discharged from the compressor flows into the condenser and is condensed, and the refrigerant condensed in the condenser is depressurized by the first decompression means. The depressurized refrigerant 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 a compressor, a second pressure reducing means, and a heat exchanger. I do. Therefore, the high-temperature and high-pressure refrigerant discharged from the compressor flows into the first bypass flow path, is depressurized 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
The heat is exchanged with the airflow flowing outside the heat exchanger to radiate heat. On the other hand, heating is performed by the heat exchanged airflow.

At the time of heating, if the pressure in the heating cycle becomes higher than a predetermined pressure due to a change in the load state, the pressure control means provided in the second bypass flow path is opened to open the heating cycle. The refrigerant flows into a flow path between the first control valve and the first pressure reducing means. Thereby, the amount of the refrigerant in the heating cycle is maintained at an appropriate amount.

[0011]

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. FIG.
FIG. 2 is a diagram showing a refrigeration cycle of the present invention, FIG. 2 is a Mollier diagram showing a state in the refrigeration cycle, and FIG. 3 is a diagram showing a gas release mechanism which is a main part of the present invention.

The refrigeration cycle according to the present invention includes a sub engine 1
1, a refrigeration cycle including a compressor (compressor) 12, a condenser (condenser) 13, a receiver 14, a supercooler 15, an expansion valve 16, and an evaporator 17 is connected by a pipe 23, 1
An electromagnetic valve (corresponding to a first control valve of the present invention) 18 is provided in the middle of a pipe 23 connecting the capacitor 2 and the condenser 13,
A first bypass flow path 24 is provided to connect a pipe 23 connecting the expansion valve 16 and the evaporator 17 with a pipe 23 between the compressor 12 and the electromagnetic valve 18. An electromagnetic valve (corresponding to a second control valve of the present invention) 19 and a pressure reducing device 20 composed of a fixed throttle are provided in the middle of the first bypass flow passage 24. Also, super cooler 15
A check valve 25 is provided between the evaporator 17 and the expansion valve 16 so that the refrigerant does not flow backward from the evaporator 17 to the expansion valve 16 and the super cooler 15.

Reference numeral 22 denotes a heater core into which cooling water for a traveling engine (not shown) flows. Reference numeral 26 denotes a blower fan for blowing air into the vehicle interior, and is driven by a motor 27 that receives the power of the sub engine 11. A second bypass flow path 28 is provided for connecting the receiver 14 with the middle of the first bypass flow path 24, and a pressure relief valve 21 is provided in the middle of the second bypass flow path 28. Reference numeral 30 denotes a radiator that flows into the sub engine 11 and into which engine cooling water for cooling the sub engine 11 flows. The radiator 30 exchanges heat with external air to cool the engine cooling water.

The compressor 12 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. Capacitor 13
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 12 and exchanges heat with external air to condense the refrigerant. The receiver 14 includes the capacitor 1
The refrigerant flowing in from 3 flows in, and only the liquid refrigerant flows into the super cooler 15.

The supercooler 15 supercools the high-pressure liquid refrigerant flowing from the receiver 14. The expansion valve 16
The high-pressure liquid refrigerant flowing from the supercooler 15 is decompressed into a low-temperature and low-pressure mist-like refrigerant. The evaporator 17 is equivalent to the heat exchanger of the present invention, in which the mist-like refrigerant which has become low temperature and low pressure flows in the expansion valve 16 and exchanges heat with the external air to cool the air. The refrigerant is a gaseous refrigerant. The evaporator 17 is arranged at least partially in series with the heater core 22. In this embodiment, the evaporator 17 is arranged in series so that all the air passing through the evaporator 17 flows into the heater core 22.

As shown in the detailed view of FIG. 3, the pressure relief valve 21 is provided with a bottomed tubular portion 213 so as to form a T-shaped path in the second bypass flow path 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 opening and closing of the solenoid valves 18 and 19 is controlled by a control unit (corresponding to the control means of the present invention) 29. The control unit 20 opens the solenoid valve 18 and closes the solenoid valve 19 during cooling, and controls the solenoid valve 19 during heating.
And the solenoid valve 18 is closed. Next, the operation of the refrigeration cycle will be described. During cooling, the solenoid valve 18 is opened and the solenoid valve 19 is closed, so that the compressor 12, the condenser 13, the receiver 14, the super cooler 15, the expansion valve 16, the evaporator A cooling cycle in which the refrigerant flows in the pipe 23 connecting the pipes 17 with each other is performed, and each part operates as described above.

On the other hand, at the time of heating, the solenoid valve 18 is closed,
By opening the solenoid valve 19, the refrigerant that has flowed out at a high temperature and a high pressure in the compressor 12 flows through the first bypass passage 24.
Flows into. This refrigerant is depressurized by the decompression device 20 and flows into the evaporator 17. Evaporator 17
The refrigerant flowing into the inside 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, by the cycle including the compressor 12, the decompression device 20, and the evaporator 17 (hereinafter, referred to as a hot gas heater cycle), in addition to the amount of heating to air in the heater core 22 as the main heating device, as well as the auxiliary heating device The air can be heated.

In this hot gas heater cycle, during high-load operation such as when the temperature in the vehicle compartment is high, the pressure in the cycle increases, and operation stops when the cycle reaches an abnormally high pressure. In order to prevent such a state, in the present invention,
A second bypass passage 28 and a pressure relief valve 21 provided in the second bypass passage 28. Since the spring 212 of the pressure relief valve 21 presses the plate 211 with a predetermined pressing force, the plate 211 closes the second bypass channel 28 when the pressure of the refrigerant in the first bypass channel 24 is lower than the predetermined pressure. It is in a state of being left. Meanwhile, the first
When the pressure of the refrigerant in the bypass flow passage 24 becomes equal to or higher than a predetermined pressure, this pressure overcomes the pressing force of the spring 212, the plate 211 is pushed up, and the first bypass flow passage 24 and the second
The bypass passage 28 communicates with the bypass passage 28. Therefore, when the pressure of the refrigerant which has been increased by the compressor 12 exceeds a predetermined pressure, the pressure relief valve 21 is opened and the refrigerant is discharged, so that an abnormally high pressure can be avoided. Note that this hot gas heater cycle includes the bypass passages 24, 2 and
Since the cooling cycle is stopped during the operation of the hot gas heater cycle, the heating operation can be continued by discharging the refrigerant to the stopped cycle side.

The state of an abnormally high pressure will be described with reference to the Mollier diagram of FIG. As shown in FIG. 2, 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 gradually increases from the state to the state, the heating operation stops 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 21, and thereafter, the heating operation is performed while maintaining the state such that the high pressure does not become abnormally high. be able to. 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.

In the present embodiment, in the hot gas heater cycle, it is possible to easily determine whether or not the high-pressure side refrigerant in the cycle is in an abnormal region with the high-pressure gas refrigerant discharged from the compressor 12. it can. In the above-mentioned hot gas heater cycle, the gas refrigerant discharged from the compressor 12 is directly depressurized by the decompression device 20 and is radiated by the evaporator 17, but as another embodiment, the refrigerant discharged from the compressor 12 is It is also possible to adopt a configuration in which heat flows directly into the evaporator 17 to radiate heat, and then the pressure is reduced by the pressure reducing device 20. In this case, in the Mollier diagram, an inverted triangle is formed as shown in the state of FIG. 2. In this cycle, the refrigerant can be discharged when the pressure of the refrigerant discharged from the compressor 12 becomes abnormally high. , A pressure relief valve 21 may be provided.

Further, in the present invention, the pressure relief valve 21 is provided in the high-pressure refrigerant pipe discharged from the compressor 12. However, the present invention is not limited to this. May be provided with a pressure relief valve 21.

[0023]

As described above, according to the air conditioner of the present invention, the pressure of the refrigerant in the heating cycle during the driving of the heating cycle including the compressor, the second pressure reducing means, and the heat exchanger is controlled. Is higher than a predetermined pressure, the pressure control means allows the refrigerant in the heating cycle to escape to a pipe not used for heating, so that the heating cycle does not become abnormally high and the heating operation is maintained. be able to.

[Brief description of the drawings]

FIG. 1 is a diagram showing a refrigeration cycle used in a vehicle air conditioner of the present invention.

FIG. 2 is a Mollier diagram.

FIG. 3 is a detailed view showing a pressure relief valve of the present invention.

[Explanation of symbols]

 12 Compressor (refrigerant compressor) 13 Condenser (condenser) 14 Receiver 15 Supercooler 16 Expansion valve (first decompression means) 17 Evaporator (Heat exchanger) 18 Solenoid valve (First control valve) 19 Solenoid valve (No. 2 control valve) 20 pressure reducing device (second pressure reducing means) 21 pressure relief valve (pressure control means) 23 pipe 24 first bypass flow path 28 second bypass flow path 29 control unit (control means)

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F25B 6/04 F25B 1/00

Claims (1)

(57) [Claims] 1. A refrigerant compressor that compresses a refrigerant into a high-temperature and high-pressure gas refrigerant, a condenser connected to a discharge side of the refrigerant compressor, and condenses the gas refrigerant compressed by the refrigerant compressor. First decompression means for decompressing the refrigerant condensed in the condenser, a heat exchanger connected to a discharge side of the first decompression means and a suction side of the refrigerant compressor, and the refrigerant compressor A first control valve provided on a path connecting the condenser and opening and closing the path; an inlet side of the first control valve bypassing the condenser and the first pressure reducing means; A first bypass flow path connecting the outlet side of the one decompression means, a second decompression means provided in the middle of the first bypass flow path to decompress a refrigerant flowing therein, and the first bypass flow path A second control valve that is provided in the middle of and opens and closes the first bypass flow path; A second bypass flow path connecting the middle of the first bypass flow path and the first control valve and the first pressure reducing means; and a second bypass flow path provided in the second bypass flow path. A pressure control means that opens when the pressure in the one bypass flow path is higher than a predetermined pressure, and closes when the pressure in the first bypass flow path is equal to or lower than the predetermined pressure; and the first control valve during cooling. An air conditioner comprising: a control unit that opens and closes the second control valve, and closes the first control valve and opens the second control valve during heating.