JP2003090582A - Control method for air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control method for an air conditioner capable of protecting a compressor by judging that a refrigerant does not flow by detecting an intermediate temperature of the temperature of an outdoor heat exchanger and that of an indoor heat exchanger, and detecting inconvenience such as a large quantity of gas leakage, full closing of an electronic expansion valve, and forgetting of two and three way valves being opened. SOLUTION: When, after the passage of a predetermined time since the starting of the operation of a compressor (ST1), discharge temperature of the compressor is lower than set temperature (ST2), room temperature and the temperature of an intermediate portion between indoor heat exchangers are detected. When a temperature difference between the detected room temperature and intermediate temperature between the indoor heat exchangers ranges within a predetermined temperature (ST3), the compressor is interrupted (ST4). After the passage of a predetermined time (ST6), the operation of the compressor is again started. When a processing of interrupting the compressor is performed continuously by the predetermined number of times when a temperature difference falls within a predetermined temperature range (ST9), a refrigerant is judged not to flow, and hence the compressor is interrupted not to be started again (ST10).

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 method of controlling an air conditioner that detects when no refrigerant flows in a refrigeration cycle to protect the compressor.

[0002]

2. Description of the Related Art Conventionally, in an air conditioner, an overload relay that responds to a temperature or an operating current is used in order to protect the compressor in the event of a malfunction such as the electronic expansion valve becoming clogged due to outgassing or foreign matter. An overload relay was added to the surface of the compressor to stop the operation of the compressor when the surface temperature of the compressor or the operating current exceeds a certain value. The discharge temperature is detected, and when the discharge temperature rises, the compressor is controlled to stop.

FIG. 4 is a refrigeration cycle diagram in a conventional heat pump type air conditioner. In the figure, 31 is a compressor, 32 is a four-way valve, 33 is an outdoor heat exchanger, 34 is an indoor heat exchanger, and 35 is an electronic expansion valve, which forms a refrigeration cycle, and cools by switching the four-way valve 32. It can be operated or heated. Further, 36 is a discharge temperature sensor for detecting the discharge temperature of the discharge port of the compressor 31.

FIG. 5 shows a conventional control block diagram, and 37 is a control section (microcomputer) for inputting the detection signal of the discharge temperature sensor 36 and controlling the compressor 31 and the like. The control unit 37 detects the temperature detected by the discharge temperature sensor 36 by A / D conversion by the discharge temperature detection unit 38, and operates the compressor 31 via the compressor drive unit 39 based on the detected temperature. To control. Further, the compressor drive unit 39, from the stop of the compressor 31,
The timer 40 measures the time until the next restart, while the counter 41 counts the number of times the compressor 31 is operated and stopped.

Next, the control operation will be described with reference to the flowchart of FIG. Discharge temperature sensor 36 during operation of the air conditioner
It is judged whether the discharge temperature detected by is 115 ℃ or more (step ST51). If it is 115 ℃ or more,
When it is judged that the refrigerant is insufficient due to gas escape from the refrigeration cycle, the compressor 31 is stopped (step ST52), and at the same time, the timer 40 sets the timer (step ST53). Step
In ST54, it is judged whether or not 3 minutes have passed after the compressor 31 was stopped, and if it has passed, the operation of the compressor 31 is restarted in step ST55, and at the same time, the counter 41 is set in step ST56, and in step ST57. It is determined whether or not the operation and stop processing of the compressor 31 has been repeated three times in succession, and if the operation has been repeated three times, the operation is permanently stopped (stopped). That is, the air conditioner is prevented from operating by remote control operation.

In the above structure, the compressor 31 can be protected by detecting the shortage of the refrigerant due to the gas release due to the rise of the discharge temperature and stopping the operation of the compressor 31. However, if the electronic expansion valve is blocked by a large amount of gas escaped from the refrigeration cycle or foreign matter, or when the air conditioner is installed,
Problems such as forgetting to open the two- and three-way valve may be difficult to detect because the refrigerant does not flow, and the temperature of the motor coil in the compressor may continue to rise, possibly leading to failure of the compressor.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is determined by the detection of the temperature of the outdoor heat exchanger and the intermediate temperature of the indoor heat exchanger that no refrigerant is flowing, An object of the present invention is to provide an air conditioner control method capable of protecting a compressor by detecting defects such as a large amount of gas leakage, a fully closed state of an electronic expansion valve, and forgetting to open a two- or three-way valve.

[0008]

In order to solve the above problems, the present invention has a refrigeration cycle in which a compressor, an indoor heat exchanger, an electronic expansion valve, and an outdoor heat exchanger are sequentially circulated, and an air conditioner After starting the operation, the temperature of the discharge port of the compressor is detected, and when the discharge temperature of the compressor exceeds the set temperature, it is judged that the refrigerant flow rate is abnormal, and the operation of the compressor is stopped to protect it. In the air conditioner consisting of, after a lapse of a predetermined time from the start of operation of the compressor, when the discharge temperature of the compressor is lower than a set temperature, the room temperature and the temperature of the intermediate portion of the indoor heat exchanger are detected, When the temperature difference between the detected room temperature and the intermediate temperature of the indoor heat exchanger is within a predetermined temperature, the compressor is stopped, and after a predetermined time elapses, the operation of the compressor is restarted, and then the temperature difference is reached. The process of stopping the compressor within a predetermined temperature continues If made constant number, it is determined that the refrigerant does not flow, and has a configuration in which a stop not to restart the compressor.

Further, it has a refrigeration cycle in which a compressor, an indoor heat exchanger, an electronic expansion valve, and an outdoor heat exchanger are sequentially circulated,
After starting the operation of the air conditioner, the temperature of the discharge port of the compressor is detected, and if the discharge temperature of the compressor exceeds the set temperature, it is judged that the refrigerant flow rate is abnormal, and the operation of the compressor is stopped. In an air conditioner configured to protect, when the discharge temperature of the compressor is lower than a set temperature after a predetermined time has passed since the start of operation of the compressor, the outside air temperature and the temperature of the outdoor heat exchanger are detected. However, when the temperature difference between the detected outside air temperature and the temperature of the outdoor heat exchanger is within a predetermined temperature, the compressor is stopped, and after a predetermined time elapses, the operation of the compressor is restarted and then the temperature is changed. If the difference is within a predetermined temperature and the process of stopping the compressor is continuously performed a predetermined number of times, it is determined that the refrigerant is not flowing, and the compressor is stopped so as not to be restarted. .

Further, it is configured such that when the refrigerant is not flowing, it is judged that the electronic expansion valve is locked while it is closed or foreign matter is mixed in the valve.

Further, the refrigerant is not flowing and it is judged that the two-way valve provided between the indoor heat exchanger and the electronic expansion valve is forgotten to be opened.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a control method for an air conditioner according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram showing a refrigeration cycle of an air conditioner according to the present invention. In the figure, 1 is a compressor, 2 is a four-way valve, 3 is an outdoor heat exchanger, 4 is an indoor heat exchanger, 5 is an electronic expansion valve, and a refrigeration cycle is formed, and cooling is performed by switching the four-way valve 2. It can be operated or heated. 6 is a room temperature sensor that detects the temperature inside the room, 7 is an indoor heat exchange temperature sensor that detects the temperature of the intermediate portion of the indoor heat exchanger 4, 8 is an outside air temperature sensor that detects the outside air temperature, and 9 is the outdoor heat exchanger 3 An outdoor heat exchange temperature sensor for detecting the temperature of 10 and a discharge temperature sensor for detecting the discharge temperature of the discharge port of the compressor 1.

FIG. 2 is a block diagram of an air conditioner to which the control method according to the present invention is applied. In the figure, this air conditioner includes an indoor control device 12 and an outdoor control device 16 each having a microcomputer, a drive circuit, and the like. The indoor control device 12 sends a predetermined command to the outdoor control device 16 in accordance with the operation of the remote controller and the temperature of the indoor heat exchanger (indoor heat exchange temperature), and the outdoor control device 16 drives the compressor 1 to the inverter according to the predetermined command. The refrigerant that is controlled and obtained in the compressor 1 is circulated to the indoor heat exchanger 4 of the indoor unit.

The indoor control device 12 detects the temperature detected by the room temperature sensor 6 by A / D conversion by the room temperature detecting section 13, while detecting the temperature detected by the indoor heat exchange temperature sensor 7 in the indoor heat exchange temperature detecting section. The A / D conversion is detected at 14, and the temperature difference between these detected temperatures and the predetermined temperature difference set in advance are compared and judged by the temperature comparison unit 15, and a predetermined command is issued according to the temperature difference. The outdoor controller 16 is configured to control the start / stop of the feed compressor 1.

The outdoor control unit 16 detects the temperature detected by the outdoor air temperature sensor 8 by A / D conversion by the outdoor air temperature detection unit 17, while detecting the temperature detected by the indoor heat and outdoor temperature sensor 9 in the outdoor heat exchange temperature. The detection unit 18 performs A / D conversion to detect the temperature difference, and the temperature comparison unit 15 compares and determines the temperature difference between these detected temperatures and a preset predetermined temperature difference, and the compressor is determined according to the temperature difference. The operation / stop of the compressor 1 is controlled via the drive unit 21.

Further, the temperature detected by the discharge temperature sensor 10 is A / D converted and detected by the discharge temperature detecting section 19, and the compressor 1 is operated via the compressor drive section 21 based on the detected temperature. Control. Further, the compressor drive unit 21 measures the time from the stop of the compressor 1 to the next restart with the timer 22, while counting the number of repetitions of the operation and stop processing of the compressor 1.
It is configured to count at 23.

FIG. 3 is a flow chart for explaining the control method of the air conditioner having the above construction. less than,
The control method of the air conditioner of the present invention will be described in detail with reference to FIG. First, the air conditioner is started for cooling or heating, and it is judged whether the compressor 1 has been operated for 30 minutes or more (step ST1). If it has passed, the discharge temperature sensor 10 detects it. It is judged whether the discharge temperature is 115 ° C or higher (step ST2). If it is 115 ° C or higher, it is judged that the refrigerant is insufficient due to gas escape from the refrigeration cycle, and the compressor 1 is stopped (step ST4), and at the same time the timer 22 is set. , Set timer (step ST
5). Next, in step ST6, it is determined whether or not 3 minutes have passed after the compressor 1 was stopped, and if so, step ST6
The operation of the compressor 1 is restarted at 7, the counter 23 is set at the same time at step ST8, and the operation of the compressor 1 is started at step ST9.
Determine if the process of stopping has been repeated three times in a row,
If it is repeated three times, the operation is stopped so as not to restart the operation in step ST10. That is, the air conditioner is prevented from operating by remote control operation.

If the discharge temperature is 115 ° C. or less in step ST2, the temperature difference between the room temperature detected by the room temperature sensor 6 in step ST3 and the indoor heat exchange temperature detected by the indoor heat exchange temperature sensor 7 is within 2 ° C. If it is within 2 ° C, it is determined that the refrigerant is not flowing in the refrigeration cycle, the compressor 1 is stopped in step ST4, and thereafter the operations from step ST5 to step ST10 are performed in the same manner as above. .

If the temperature difference between the room temperature and the indoor heat exchange temperature is 2 ° C. or more in step ST3, the outdoor air temperature detected by the outdoor air temperature sensor 8 and the outdoor heat detected by the outdoor heat exchange temperature sensor 9 in step ST11. It is determined whether or not the temperature difference from the cross temperature is within 2 ° C. If it is within 2 ° C, it is determined that the refrigerant is not flowing in the refrigeration cycle, the compressor 1 is stopped in step ST4, and the same as above. The operations from step ST5 to step ST10 are performed.

As explained above, the discharge temperature is 115 ° C.
In the following, when the temperature difference between the room temperature and the indoor heat exchange temperature is within 2 ° C or the temperature difference between the outside air temperature and the outdoor heat exchange temperature is within 2 ° C, the refrigerant is not flowing in the refrigeration cycle, that is,
A large amount of gas has escaped from the refrigeration cycle, is completely out of gas, is the electronic expansion valve 5 locked while it is still closed, or is the valve fully closed due to foreign matter entering the valve, or forgetting to open the 2-, 3-way valve, etc. It can be judged that there is a problem with the above, and the compressor can be stopped and protected.

[0021]

As described above, according to the air conditioner control method of the present invention, the temperature difference between the room temperature and the indoor heat exchange temperature is within 2 ° C., or the temperature between the outdoor air temperature and the outdoor heat exchange temperature. If the difference is within 2 ° C., the refrigerant is not flowing in the refrigeration cycle, that is, a large amount of gas is completely removed from the refrigeration cycle, or the electronic expansion valve is locked while being closed, or The compressor can be stopped and protected by determining that the valve is completely closed due to foreign matter mixed in, or that the two-way valve has not been opened.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a refrigeration cycle of an air conditioner according to the present invention.

FIG. 2 is a block diagram of an air conditioner according to the present invention.

FIG. 3 is a flowchart of a method for controlling an air conditioner according to the present invention.

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

FIG. 5 is a block diagram of an air conditioner according to a conventional example.

FIG. 6 is a flowchart of a control method for an air conditioner according to a conventional example.

[Explanation of symbols]

1 compressor 2 four-way valve 3 outdoor heat exchanger 4 Indoor heat exchanger 5 Electronic expansion valve 6 Room temperature sensor 7 Indoor heat exchange temperature sensor 8 Outside temperature sensor 9 Outdoor heat exchange temperature sensor 10 Discharge temperature sensor 12 Indoor control device 13 Room temperature detector 14 Indoor heat exchange temperature detector 15 Temperature comparison part 16 Outdoor control device 17 Outside temperature detector 18 Outdoor heat exchange temperature detector 19 Discharge temperature detector 20 Temperature comparison part 21 Compressor drive 22 timer 23 counter

Claims (4)

[Claims] 1. A refrigeration cycle in which a compressor, an indoor heat exchanger, an electronic expansion valve, and an outdoor heat exchanger are sequentially circulated, and after the operation of the air conditioner is started, the temperature of the discharge port of the compressor is detected, In the air conditioner, which determines that the refrigerant flow rate is abnormal when the discharge temperature of the compressor exceeds a set temperature, and stops the operation of the compressor to protect it, the operation of the compressor is started. After a predetermined time from, if the discharge temperature of the compressor is lower than the set temperature, the temperature between the room temperature and the intermediate portion of the indoor heat exchanger is detected, and the detected room temperature and the intermediate portion temperature of the indoor heat exchanger are When the temperature difference is within a predetermined temperature, the compressor is stopped, after a predetermined time elapses, the operation of the compressor is restarted, and then the process of stopping the compressor within the predetermined temperature difference is continued. After a predetermined number of times, it is determined that the refrigerant is not flowing. The control method of an air conditioner characterized by comprising stop not to restart the compressor. 2. A refrigeration cycle in which a compressor, an indoor heat exchanger, an electronic expansion valve, and an outdoor heat exchanger are sequentially circulated, and after the operation of the air conditioner is started, the temperature of the discharge port of the compressor is detected, In the air conditioner, which determines that the refrigerant flow rate is abnormal when the discharge temperature of the compressor exceeds a set temperature, and stops the operation of the compressor to protect it, the operation of the compressor is started. After a lapse of a predetermined time from, if the discharge temperature of the compressor is lower than the set temperature, the outside air temperature and the temperature of the outdoor heat exchanger are detected, and the temperature difference between the detected outside air temperature and the temperature of the outdoor heat exchanger is When the temperature is within a predetermined temperature, the compressor is stopped, after a predetermined time has elapsed, the operation of the compressor is restarted, and then the process of stopping the compressor within the predetermined temperature difference is within a predetermined number of times consecutively. If done,
A method for controlling an air conditioner, characterized in that it is judged that no refrigerant is flowing and the compressor is stopped so as not to be restarted. 3. The method according to claim 1, wherein the state in which the refrigerant is not flowing is determined as the electronic expansion valve is locked while being closed or foreign matter is mixed in the valve. A method for controlling the air conditioner described. 4. The method according to claim 1, wherein the state in which the refrigerant is not flowing is determined as a failure to open a two-way valve provided between the indoor heat exchanger and the electronic expansion valve. The method for controlling an air conditioner according to claim 2.