JP2882172B2 - 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 a control device.

[0002]

2. Description of the Related Art FIG.
FIG. 1 shows a refrigerant circuit of a conventional air conditioner shown in Japanese Patent Application Publication No. 5 (1993) -207, in which 1 is a compressor that compresses and discharges refrigerant, 2 is a four-way valve that switches refrigerant inlet and outlet to this compressor 1, and 3 is An outdoor heat exchanger, 4 is an electric expansion valve, and 5 is an indoor heat exchanger. The compressor 1, the four-way valve 2, the outdoor heat exchanger 3, and the electric expansion valve 4 are sequentially connected by a refrigerant pipe 6, and a refrigerant circuit is provided. Is composed. Reference numeral 7 denotes a bypass pipe which connects the discharge-side high-pressure pipe 6a and the suction-side low-pressure pipe 6b of the compressor 1 to each other. Reference numeral 8 denotes a solenoid valve provided in the middle of the bypass pipe 7. 9 the control unit for operating the control device including the indoor unit of the electromagnetic valve 8, 10 is a detector for detecting the discharged refrigerant gas temperature.

Next, the operation will be described. During cooling operation, the refrigerant is sent to the outdoor heat exchanger 3 through the four-way valve 2 from the compressor 1, after liquefied by condensation at depressurized chamber heat exchanger 5 by the electric expansion valve 4 It evaporates and becomes a gas refrigerant, passes through the four-way valve 2 and returns to the compressor 1.

In the state where such a cooling operation cycle is formed, if the temperature of the discharged refrigerant gas rises above a set temperature considered to be abnormal in the formation of the refrigeration cycle, the control unit 9 detects this. Compressor 1 detected by compressor 10
Is controlled to stop temporarily. At this time, the control unit 9 performs control so that the solenoid valve 8 of the bypass pipe 7 which has been closed up to now is simultaneously opened. By performing these controls, the refrigerant gas once discharged from the compressor 1 is controlled. Is liquefied and flows backward due to the stoppage of the compressor 1, a part of it flows into the low pressure side pipe 6b via the bypass pipe 7, and the pressure in the cycle pipe is balanced without the discharge pipe 6a becoming high pressure. And the refrigeration cycle is restarted without applying a high load when the compressor 1 is restarted.

[0005]

The control device of the conventional air conditioner is configured as described above. During the cooling operation, when the cooling air is overloaded, such as when the outside air temperature is high, the temperature and pressure of the refrigerant are abnormal. When the operation of the protection device is detected due to a rise or the like, the operation of the air conditioner is stopped, and there has been a problem that the cooling effect cannot be achieved. Further, when the protection device is operated under an overload condition or the like, if the protection device is once stopped, it may not be possible to restart even if the bypass valve is opened.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is possible to prevent an air conditioner from being frequently stopped abnormally under an overload condition during a cooling operation, and to prevent an overrun during a cooling operation. An object of the present invention is to provide a control unit of an air conditioner capable of expanding an operation range under a load condition.

[0007]

In the air conditioner according to the present invention, a refrigeration cycle in which a compressor, an outdoor heat exchanger, a pressure reducing means, and an indoor heat exchanger are sequentially connected by a refrigerant pipe; A bypass pipe connected via a solenoid valve to a refrigerant pipe connecting the pressure reducing means and the indoor heat exchanger from the refrigerant discharge side, and a detecting means for detecting the temperature or pressure of the outdoor heat exchanger, Control means for opening the solenoid valve at a value lower than a predetermined value corresponding to the temperature or pressure of the outdoor heat exchanger when the output signal of the detecting means is in the cooling operation overload state.

[0008]

In the air conditioner configured as described above, during the cooling operation, the temperature or pressure of the outdoor heat exchanger that condenses the refrigerant reaches a value lower than a predetermined value that causes the operation to stop in the cooling overload state. At this point, the electromagnetic valve is opened by the control means, the flow rate of the refrigerant to the outdoor heat exchanger is reduced, and the operation of the air conditioner is continued by preventing the protection device from operating.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 11 denotes operation input means which operates in response to operation command input ON / OFF from an input terminal 11a;
12 is a temperature or pressure detecting means of the outdoor heat exchanger 3 for detecting a temperature or pressure value of the outdoor heat exchanger 3 from the thermistor or the pressure sensor 13, and 14 is the operation command input means 1.
1 based on the output signal from the compressor 1 and the output signal from the temperature or pressure detecting means 12 of the outdoor heat exchanger 3 to start / stop the electric equipment such as the compressor 1 and the solenoid valve 8 and to hold / check the self-maintenance when an abnormality occurs. The control means 14 controls a mode and a restart. The control means 14 is connected to a compressor drive means 1a, a display drive means 15 and a solenoid valve drive means 8a which are controlled by the command output. The compressor 1 is connected to 1a, the electromagnetic valve 8 is connected to the electromagnetic valve driving means 8a, and the display 16 for displaying an abnormality is connected to the display driving means 15.

FIG. 2 is a configuration diagram of a refrigeration cycle showing the embodiment of FIG. In FIG. 2, 1 is a compressor that compresses and discharges refrigerant, 2 is a four-way valve that switches the refrigerant inflow path to the compressor 1 and the destination of compressed refrigerant, 3 is an outdoor heat exchanger, 4 is a decompression device, and 5 is an indoor unit. It is a heat exchanger. These are sequentially connected by a refrigerant pipe to form a refrigerant circuit of the air conditioner. 13 is installed on the refrigerant pipe in the vicinity of the outdoor heat exchanger 3, and a thermistor as a temperature detecting means or a pressure sensor as a pressure detecting means of the refrigerant pipe, 7 is a pressure reducing device 4 from the discharge end of the compressor 1 A bypass pipe 8 connected to a pipe 6 connecting the heat exchanger 5 and the indoor heat exchanger 5 is an electromagnetic valve disposed in the bypass pipe 7.

Hereinafter, the operation of the air conditioner having the above configuration will be described. During the cooling operation, the high-temperature and high-pressure refrigerant gas discharged from the compressor 1 is supplied to the outdoor heat exchanger 3 via the four-way valve 2 so that heat is exchanged with outdoor air to become a high-pressure liquid refrigerant. Then this high-pressure liquid refrigerant, is more reduced pressure to pass through the pressure reducing device 4, further at home through the indoor heat exchanger 5, low-pressure refrigerant is evaporated by performing the cooling by exchanging heat with indoor air It becomes gas. And
The low-pressure refrigerant gas is sucked into the compressor 1 through the four-way valve 2 and is compressed again and discharged as a high-temperature and high-pressure refrigerant gas, thereby forming a refrigeration cycle.

Here, the cooling operation mode input terminal 11a
When an operation ON command is input to the control unit 14, an operation ON command signal is output from the operation command input unit 11 and is taken into the control unit 14. The control means 14 outputs an operation command to the compressor drive means 1a in accordance with the operation ON command signal, and by operating this, power is supplied to the electric compressor 1 and the compressor 1 is operated by operating the compressor 1 Construct a refrigeration cycle and operate the air conditioner.

In such a cooling operation state, the temperature or pressure of the outdoor heat exchanger 3 by the thermistor or pressure sensor 13 is detected by the outdoor heat exchanger temperature or pressure detecting means 12, and an output signal is sent to the control means 14. When the temperature or pressure of the outdoor heat exchanger 3 reaches a second predetermined value lower than the first predetermined value at which the cooling operation is stopped, the control unit 14 outputs to the electromagnetic valve driving unit 8a to open the electromagnetic valve 8. .

When the solenoid valve 8 is opened, the compressor 1
A part of the high-temperature and high-pressure refrigerant gas discharged from the refrigerant is distributed to the low-pressure refrigerant gas side depressurized by the decompression device 4 through the bypass pipe 7, and the flow rate of the refrigerant flowing to the outdoor heat exchanger 3 is reduced, so that the outdoor heat The temperature or pressure of the exchanger 3 decreases. Therefore, during the cooling operation, the air conditioner does not abnormally stop under the overload condition.

[0015] Next the operation of the air conditioner based on the flowchart shown in FIG. First, step 3
In step 1, the cooling operation mode is set. In the next step 32, the control unit sends an output signal to the solenoid valve driving unit 8a to close the solenoid valve 8. In the next step 33, it is determined whether or not an operation command has been input from the input terminal 11a. If the operation command signal is OFF, the process proceeds to step 42, in which the compressor 1 is stopped, and the process proceeds to step 43 stop mode. If the operation command signal is ON, the routine proceeds to step 34, where power is supplied from the control means to the compressor 1, and the compressor 1 is driven to start the operation of the air conditioner. Then, the process proceeds to the next step 35 . Steps
At 35 , by the thermistor or pressure sensor 13 ,
Temperature or pressure detecting means for detecting the temperature or pressure of the outdoor heat exchanger 3
Then , the output signal is sent to the control means, and the flow advances to step 46. In the next step 46, the control means controls the temperature T or the pressure value P of the outdoor heat exchanger 3 and the predetermined temperature T _1.
Alternatively, it is compared with a predetermined pressure P ₁ to determine whether T> T ₁ or P> P ₁ . If the determination in step 46 is No, the process returns to step 33.
If the determination in step 46 is Yes, the process proceeds to step 47. In the next step 47, the control means 1
In step 4, the output is output to the solenoid valve driving means 8a to open the solenoid valve 8, and the flow advances to the next step 48. In step 48, the temperature or pressure of the outdoor heat exchanger 3 is detected by the temperature or pressure detecting means 12 by the thermistor or the pressure sensor 13, and an output signal is sent to the control means 14 , and the process proceeds to step 49. And the temperature T or the pressure value P of the outdoor heat exchanger 3 in the next step 49 the control unit 14 compares the predetermined temperature T ₀ or the predetermined pressure P _0, T> or a T ₀ or P> P ₀ not Is determined.

If the determination in step 49 is Yes, it is determined that the protection device is activated, and the routine proceeds to step 52. In the next step 52, the control means 14 outputs a stop command to the compressor driving means 1a to stop the operation of the compressor 1 and proceeds to step 53. In step 53, the control means 14 outputs the signal to the abnormality display drive means 15, and the display 16
Is turned on to display an abnormality, and the process proceeds to the next step 54 lighting mode. If the determination in step 49 is No, the process proceeds to step 55. In step 55, the temperature or pressure of the outdoor heat exchanger 3 is detected by the temperature or pressure detecting means 12 by the thermistor or the pressure sensor 13, and an output signal is sent to the control means 14. It compares the temperature T or the pressure value P of the outdoor heat exchanger 3 in the next step 50 the control unit 14, and a predetermined temperature T ₂ or a predetermined pressure P _2, whether it is T ≦ T ₂ or P ≦ P ₂ whether Is determined. If the determination in step 50 is No, the process returns to step 47. Also,
If the determination in step 50 is Yes, the process proceeds to step 51. In the next step 51, the control means 14 sends an output signal to the solenoid valve driving means 8a to close the solenoid valve 8 and returns to step 33.

Therefore, during the cooling operation, the air conditioner can be operated without activating the protection device and stopping abnormally according to the protection device operating condition (operating condition).
This has the effect of expanding the operating range under overload conditions.

Since the present invention is configured as described above, even if the outside air temperature rises and the temperature and pressure of the refrigerant increase, the solenoid valve is opened and the high temperature and high pressure refrigerant are bypassed to the low pressure side. Since the refrigerant is always maintained at a predetermined temperature and pressure or lower, it is possible to prevent an accident such as a pressure machine bearing caused by a rise in the temperature and pressure of the refrigerant, and to continue the operation even in an overload condition. Thus, an air conditioner that is easy to use and highly reliable can be obtained.

[Brief description of the drawings]

FIG. 1 is a principle block diagram showing a configuration of a control device for an air conditioner according to the present invention.

FIG. 2 is a configuration diagram of a refrigeration cycle showing an embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the second embodiment of the present invention.

FIG. 4 is a refrigeration cycle configuration diagram showing an example of a conventional air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 3 Outdoor heat exchanger 4 Decompression means 7 Bypass piping 8 Solenoid valve 14 Control means

Claims (1)

(57) [Claims] 1. A refrigeration cycle in which a compressor, an outdoor heat exchanger, a pressure reducing means, and an indoor heat exchanger are sequentially connected by refrigerant pipes, and a discharge side of the compressor and suction of the indoor heat exchanger.
A bypass pipe connecting the inlet side via a solenoid valve,
Detecting means for detecting the temperature or pressure of the outdoor heat exchanger;
Control the opening and closing of the solenoid valve by the output signal of the detection means.
Control means, wherein the control means outputs the output signal of the detection means.
Is the temperature of the outdoor heat exchanger when the cooling operation is overloaded.
Opens the solenoid valve at a value lower than the specified value corresponding to the pressure.
An air conditioner characterized by being adapted to release.