JPH07158980A - Expansion valve controller for air conditioner - Google Patents

Abstract

PURPOSE:To prevent freezing of an indoor heat exchanger, to prevent a decrease in a discharge temperature, and to reduce a change of the discharge temperature. CONSTITUTION:An air conditioner capable of cooling is formed by annularly coupling a compressor 1, an indoor heat exchanger, an expansion valve 2, and an outdoor heat exchanger as a refrigerating cycle. An expansion valve controller for the conditioner comprises an atmospheric temperature sensor 4 for sensing an atmospheric temperature, a comparator 4a for comparing the detected temperature with a set temperature, and expansion valve control means for altering to shift the valve to an opening direction if an opening proportional relationship between a compressor operating frequency and the valve is higher than a compressor operating frequency from a comparison result or to shift it to a closing direction if it is lower than the frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expansion valve control device for cooling operation of an air conditioner.

[0002]

2. Description of the Related Art Conventionally, the expansion valve control of an air conditioner is based on the proportional relationship between the compressor operating frequency and the opening of the expansion valve.
Further, the opening degree of the expansion valve is changed according to the degree of superheat.

[0003]

By the way, when the cooling operation is carried out under the condition of low outside air temperature, the temperature outside the room is low, so that the heat radiation effect is large, the rise of the high pressure of the refrigeration cycle is small, and the pressure of the indoor heat exchanger is also small. When the temperature drops and the blowout temperature is operated near zero, it causes discomfort to the human body and air-conditioning disease. There is also control that turns on and off the outdoor blower so that it can be operated at a low outside air temperature, but at this time the blowing temperature changes greatly, causing discomfort due to changes in the cold air temperature, and increasing the efficiency. It is bad driving. In this way, comfort, health,
In operation efficiency, there is a problem in cooling operation at low outside air temperature.

In view of the above-mentioned problems, the present invention prevents freezing of the indoor heat exchanger in a cooling operation under a low outside air temperature condition, expands the cooling operation range, prevents the blowout temperature from lowering, and improves the blowout temperature. It is an object of the present invention to provide an expansion valve control device that minimizes changes.

[0005]

To achieve the above object, the present invention provides an air conditioner capable of cooling operation by annularly connecting a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger as a refrigeration cycle. Of the compressor, detecting means for detecting the outside air temperature, comparing means for comparing the detected temperature with the set temperature, and there is a proportional relationship between the compressor operating frequency and the opening degree of the expansion valve according to the comparison result. If the frequency is higher than the frequency, a shift is performed in the opening direction, and if the frequency is lower than a certain frequency, a shift is performed in the closing direction.

Further, the present invention has the refrigeration cycle described above, and a detecting means for detecting the outside air temperature, a comparing means for comparing the detected temperature with a set temperature, and a compression by the comparison result. An expansion valve control means is provided which shifts the proportional relationship between the machine operating frequency and the opening degree of the expansion valve in the opening direction stepwise according to the change of the outside air temperature at the same frequency.

[0007]

According to the present invention, in the above-described structure, the outside air temperature is detected, the detected temperature value is compared with the set temperature, and if the temperature is lower than the set temperature, the compressor operating frequency and the expansion are expanded. Expansion valve control is performed to change the proportional relationship of the valve opening. As a result, the operable range of cooling under low-temperature conditions indoors and outdoors is widened to prevent an extreme drop in the blowing temperature.

The present invention also relates to the operating current of the outdoor blower,
The expansion valve is controlled by accurately recognizing that the outdoor blower control at a low outside air temperature has operated, and further, the fluctuation of the blowing temperature is reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An expansion valve control device for an air conditioner according to an embodiment of the present invention will be described below with reference to the drawings.

First, a first embodiment of the control device of the present invention will be described with reference to FIGS. In FIG. 1, as components of the refrigeration cycle, 1 is a variable frequency compressor, 2 is an expansion valve, 12 is an outdoor heat exchanger, 13 is an indoor heat exchanger, 14 is an outdoor blower, and 15 is an indoor blower.

In FIG. 3, reference numeral 11 is an outdoor unit main body, and 4 is an outside air temperature detecting thermistor, which inputs a temperature change to the outdoor microcomputer 3 as a divided voltage with the resistor Ra. The outside air temperature data is compared and examined by the comparison device 4a with a preset temperature, and based on the comparison result, an instruction to change the compressor operating frequency and the proportional relationship of the opening degree of the expansion valve is given.
The expansion valve 2 is controlled. In FIG. 3, 5 is an outdoor fan, 6 is a current detection device, 7 is a pipe sensor,
Reference numeral 8 is a pressure sensor, 4a, 6a, 7a and 8a are comparison devices, 9 is a power source, and 10 is a power transistor.

The control operation of this embodiment will be described with reference to FIGS. 4 and 12. A cooling operation is performed by initially setting the set outdoor air temperature, the compressor operating frequency at which the basic expansion valve is opened, and the expansion valve opening proportional relationship. The outside air temperature T0 is detected by the detecting means, and if the outside air temperature T0 is lower than the set temperature T01 due to the decrease in the detected outside air temperature T0, the expansion valve 2 opens the expansion valve opening direction when it is higher than a certain compressor operating frequency. When the shift is changed and is lower than a certain compressor operating frequency, the expansion valve opening is changed to the closing direction. This shift change changes the proportional relationship between the compressor operating frequency and the expansion valve.

Next, a second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 3, this embodiment has a current detection device 6 attached to the outdoor blower, and the current detection device 6 converts the current into a voltage. The current detected by the current detection device 6 is input to the outdoor microcomputer 3 as a voltage change. With this signal, the current data is compared and examined by the comparison device 6a with the preset current, and based on the comparison result, the compressor operating frequency and the expansion valve opening proportional relation change instruction are given to control the expansion valve 2. .

The control operation of this embodiment will be described with reference to FIGS. The set outdoor blower operating current, the compressor operating frequency that becomes the basic expansion valve opening, and the proportional relationship of the opening of the expansion valve are initialized, and the cooling operation is performed. The current A0 is detected by the detection means, and if the outdoor blower current A0 is lower than the set current A01 due to the decrease in the detected outdoor blower current A0, the expansion valve 2 opens the expansion valve opening direction if the expansion valve 2 is higher than a certain compressor operating frequency. When the frequency is lower than a certain compressor operating frequency, the expansion valve opening is shifted in the closing direction. This shift change changes the proportional relationship between the compressor operating frequency and the expansion valve.

Next, a third embodiment of the present invention will be described with reference to FIG. This embodiment has an outdoor pipe temperature thermistor 7, and the voltage is input to the outdoor microcomputer 3 by using the temperature change as a divided voltage with the resistor Rb. The pipe temperature data is compared and examined by the comparison device 7a with a preset pipe temperature, and based on the comparison result, the expansion valve 2 is controlled by instructing the change of the compressor operating frequency and the expansion valve opening proportional relationship.

The control operation of this embodiment will be described with reference to FIGS. 6 and 14. The cooling operation is performed by initially setting the set pipe temperature, the compressor operating frequency that becomes the basic expansion valve opening, and the expansion valve opening proportional relationship. The pipe temperature Th is detected by the detecting means, and if the pipe temperature Th is lower than the set temperature Th1 due to the decrease in the detected pipe temperature Th, the expansion valve 2 opens the expansion valve opening direction when the expansion valve 2 is higher than a certain compressor operating frequency. When the frequency is lower than a certain compressor operating frequency, the expansion valve opening is shifted in the closing direction. This shift change changes the proportional relationship between the compressor operating frequency and the expansion valve.

Next, a fourth embodiment of the present invention will be described with reference to FIG. This embodiment has a pressure sensor 8 attached to the outdoor heat exchanger, which converts the pressure into a voltage. The outdoor microcomputer 3 uses the pressure detected by the pressure sensor 8 as a voltage change.
To enter. This signal causes the pressure data to be compared with the comparison device 8a.
Thus, the pressure is compared with a preset pressure, and based on the result, the change of the compressor operating frequency and the proportional relationship of the opening degree of the expansion valve is instructed to control the expansion valve 2.

The control operation of this embodiment will be described with reference to FIGS. 7 and 15. A cooling operation is performed by initially setting the set pressure, the compressor operating frequency that becomes the basic expansion valve opening, and the expansion valve opening proportional relationship. The pressure P0 is detected by the detecting means, and if the pressure P0 is lower than the set pressure P1 due to the decrease in the detected pressure P0, the expansion valve 2 shifts the opening degree of the expansion valve in the opening direction when the expansion valve 2 is higher than a certain compressor operating frequency. If it is lower than a certain compressor operating frequency, the expansion valve opening degree is shifted and changed to the closing direction. This shift change changes the proportional relationship between the compressor operating frequency and the expansion valve.

Next, a fifth embodiment of the present invention will be described with reference to FIG. This embodiment has an outside air temperature detecting thermistor 4 and inputs the temperature change to the outdoor microcomputer 3 as a divided voltage with the resistor Ra. The outside air temperature data is compared and examined with a preset temperature by the comparison device 4a, and based on the comparison result, the expansion valve 2 is controlled by instructing the change of the compressor operating frequency and the expansion valve opening proportional relationship.

The control operation of this embodiment will be described with reference to FIGS. A cooling operation is performed by initially setting the set outdoor air temperature, the compressor operating frequency at which the basic expansion valve is opened, and the expansion valve opening proportional relationship. The outside air temperature T0 is detected by the detection means, and if the outside air temperature T0 is lower than the set temperature T01 due to the decrease in the detected outside air temperature T0, the expansion valve 2 shifts the opening degree stepwise at the same frequency. This shift change changes the proportional relationship between the compressor operating frequency and the expansion valve.

Next, a sixth embodiment of the present invention will be described with reference to FIG. This embodiment has a current detecting device 6 attached to the outdoor blower, and the current detecting device 6 converts the current into a voltage. The current detected by the current detection device 6 is input to the outdoor microcomputer 3 as a voltage change. With this signal, the current data is compared and examined by the comparison device 6a with the preset current, and based on the comparison result, the compressor operating frequency and the expansion valve opening proportional relation change instruction are given to control the expansion valve 2. .

The control operation of this embodiment will be described with reference to FIGS. 9 and 13. The set outdoor blower operating current, the compressor operating frequency that becomes the basic expansion valve opening, and the proportional relationship of the opening of the expansion valve are initialized, and the cooling operation is performed. The current A0 is detected by the detecting means, and if the outdoor blower current A0 is lower than the set current A01 due to the decrease in the detected outdoor blower current A0, the expansion valve 2 shifts the opening degree stepwise at the same frequency. This shift change changes the proportional relationship between the compressor operating frequency and the expansion valve.

Next, a seventh embodiment of the present invention will be described with reference to FIG. This embodiment has an outdoor pipe temperature thermistor 7, and the voltage is input to the outdoor microcomputer 3 by using the temperature change as a divided voltage with the resistor Rb. The pipe temperature data is compared and examined by the comparison device 7a with a preset pipe temperature, and based on the comparison result, an instruction to change the compressor operating frequency and the expansion valve opening proportional relationship is given.
Control the expansion valve 2.

The control operation of this embodiment will be described with reference to FIGS. The cooling operation is performed by initially setting the set pipe temperature, the compressor operating frequency that becomes the basic expansion valve opening, and the expansion valve opening proportional relationship. The pipe temperature Th is detected by the detecting means, and if the pipe temperature Th is lower than the set temperature Th1 due to the decrease in the detected pipe temperature Th, the expansion valve 2 shifts the opening degree stepwise at the same frequency. This shift change changes the proportional relationship between the compressor operating frequency and the expansion valve.

Next, an eighth embodiment of the present invention will be described with reference to FIG. This embodiment has a pressure sensor 8 attached to the outdoor heat exchanger, converting pressure into voltage. The pressure detected by the pressure sensor 8 is input to the outdoor microcomputer 3 as a voltage change. With this signal, the pressure data is compared and examined by the comparison device 8a with a preset pressure, and from the proportional result, an instruction to change the compressor operating frequency and the proportional relationship of the opening of the expansion valve is given.
Control the expansion valve 2.

The control operation of this embodiment will be described with reference to FIGS. 11 and 15. A cooling operation is performed by initially setting the set pressure, the compressor operating frequency that becomes the basic expansion valve opening, and the expansion valve opening proportional relationship.

The pressure P0 is detected by the detecting means, and if the pressure P0 is lower than the set pressure P1 due to the decrease in the detected pressure P0, the expansion valve 2 shifts the opening degree stepwise at the same frequency. This shift change changes the proportional relationship between the compressor operating frequency and the expansion valve.

The control and operation results of the expansion valve will be described with reference to FIGS. 16, 17, and 18 by the configuration and control operation of each of the above embodiments. FIG. 16 shows the first to fourth embodiments.
The operation of the expansion valve up to the embodiment, the opening of the basic expansion valve, the detection result by the detection means is compared with a preset value, the opening of the expansion valve is shifted by the comparison result. To do.

The opening shift of the expansion valve is changed in the opening direction when the operating frequency of the variable frequency compressor is higher than a certain frequency, and is changed in the closing direction when the operating frequency is lower than a certain compressor operating frequency. .

FIG. 17 shows the control operation of the expansion valve from the fifth embodiment to the eighth embodiment, and the opening degree of the basic expansion valve is
The detection result of the detection means is compared with a preset value, and the opening degree of the expansion valve is shifted according to the comparison result. This opening shift of the expansion valve shifts the opening in a stepwise manner when the operating frequency of the variable frequency compressor is the same.

By changing the opening degree of the expansion valve with respect to the frequency as described above, it is possible to further reduce the rate of change of the blowout temperature or decrease the drop of the blowout temperature at a high frequency. Further, the small opening shift in the low frequency operation is effective in securing the pressure difference of the compressor in the refrigeration cycle to prevent the liquid pool phenomenon in the refrigeration cycle and performing the operation with high efficiency.

FIG. 8 shows the change of the blowout temperature by shifting the opening degree of the expansion valve in FIGS. By changing the opening of the expansion valve, the change time of the outdoor pressure changes from S1 at the basic expansion valve opening to S2 at the expansion valve opening shift. As a result, the change time of the blowout temperature changes from S1 to S2, and the change width changes from W1 to W2.

[0033]

As is clear from the description of the above embodiment,
The present invention, in the cooling operation under low indoor and outdoor air temperature conditions,
Depending on the change in the outdoor heat exchanger temperature, the compressor operating frequency and the expansion valve opening proportional shift are changed to prevent freezing of the indoor heat exchanger, widen the cooling operation range, and lower the blowout temperature. It has a preventive effect.

Further, by detecting the pressure with the pressure sensor, there is an effect that reliable control can be performed even in a transient state without being affected by the degree of superheat of the refrigeration cycle. Further, by detecting the outdoor blower current with the current detection device, there is an effect that the variation range of the blowout temperature can be reduced, and the outdoor blower can be controlled by a method that is structurally simple and inexpensive.

[Brief description of drawings]

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

[Fig. 2] Relationship between conventional operating frequency and expansion valve opening

FIG. 3 is a configuration diagram of an expansion valve control device according to an embodiment of the present invention.

FIG. 4 is a flowchart of expansion valve control according to an embodiment of the present invention.

FIG. 5 is a flowchart of expansion valve control according to another embodiment of the present invention.

FIG. 6 is a flowchart of expansion valve control according to another embodiment of the present invention.

FIG. 7 is a flowchart of expansion valve control according to another embodiment of the present invention.

FIG. 8 is a flowchart of expansion valve control according to another embodiment of the present invention.

FIG. 9 is a flowchart of expansion valve control according to another embodiment of the present invention.

FIG. 10 is a flowchart of expansion valve control according to another embodiment of the present invention.

FIG. 11 is a flowchart of expansion valve control according to another embodiment of the present invention.

FIG. 12 is an operation explanatory diagram of expansion valve control according to an embodiment of the present invention.

FIG. 13 is an operation explanatory diagram of an expansion valve control according to another embodiment of the present invention.

FIG. 14 is an operation explanatory diagram of expansion valve control according to another embodiment of the present invention.

FIG. 15 is an operation explanatory view of expansion valve control according to another embodiment of the present invention.

FIG. 16 is a diagram showing the relationship between the operating frequency and the expansion valve opening according to the embodiment of this invention.

FIG. 17 is a relationship diagram between the operating frequency and the expansion valve opening degree according to the embodiment of this invention

FIG. 18 is a relational diagram of the basic expansion valve opening and the expansion valve opening shift in the embodiment of the present invention.

[Explanation of symbols]

 1 Variable Frequency Compressor 2 Expansion Valve 3 Microcomputer 4 Outdoor Air Temperature Thermistor 5 Outdoor Blower 6 Current Detector 7 Outdoor Pipe Temperature Thermistor 8 Pressure Sensors 4a-8a Comparison Device 11 Outdoor Unit 12 Outdoor Heat Exchanger 13 Indoor Heat Exchanger 14 Outdoor Blower

Claims (8)

[Claims] 1. A detection means for detecting an outside air temperature, which constitutes an air conditioner capable of cooling operation by annularly connecting a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger as a refrigeration cycle, and a detecting means therefor. Comparison means for comparing the detected temperature and the set temperature, and if the comparison result indicates that the compressor operating frequency and the expansion valve opening proportional relationship are higher than a certain compressor operating frequency, a shift change is performed in the opening direction. Further, an expansion valve control device for an air conditioner, which is provided with an expansion valve control means for changing a shift in a closing direction if the frequency is lower than a certain compressor operating frequency. 2. A detection means for detecting an operating current of an outdoor blower by constructing an air conditioner capable of cooling operation by annularly connecting a compressor, an indoor heat exchanger, an expansion valve and an outdoor heat exchanger as a refrigeration cycle. And a comparing means for comparing the detected current with the set current, and if the comparison result shows that the compressor operating frequency and the opening degree of the expansion valve are higher than a certain compressor operating frequency, the shift is changed to the opening direction. In addition, the expansion valve control device for an air conditioner is provided with an expansion valve control means for performing shift change in a closing direction if the operation frequency is lower than a certain compressor operating frequency. 3. An air conditioner capable of cooling operation is constructed by annularly connecting a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger as a refrigeration cycle, and heat is exchanged by the outdoor heat exchanger. The detecting means for detecting the temperature, the comparing means for comparing the detected temperature with the set temperature, and the comparison result shows that the compressor operating frequency and the expansion valve opening proportional relationship are higher than a certain compressor operating frequency. An expansion valve control device for an air conditioner, comprising: an expansion valve control means for changing the shift in the opening direction and for changing the shift in the closing direction if the frequency is lower than a certain compressor operating frequency. 4. A detection means for detecting pressure from a pressure detector, which constitutes an air conditioner capable of cooling operation by annularly connecting a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger as a refrigeration cycle. And a comparison means for comparing the detected pressure with the set pressure, and if the comparison result shows that the compressor operating frequency and the expansion valve opening proportional relationship are higher than a certain compressor operating frequency, the shift change in the opening direction is changed. An expansion valve control device for an air conditioner, which is provided with expansion valve control means for performing a shift change in a closing direction if the operation frequency is lower than a certain compressor operating frequency. 5. A detection means for detecting the outside air temperature, which constitutes an air conditioner capable of cooling operation by annularly connecting a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger as a refrigeration cycle, and a detecting means therefor. Comparing means for comparing the detected temperature with the set temperature, and by the comparison result, the compressor operating frequency and the opening proportionality relationship of the expansion valve are changed stepwise according to the change of the outside air temperature at the same frequency, An expansion valve control device for an air conditioner, which is provided with an expansion valve control means for changing a shift in an opening direction. 6. A detection means for detecting an operating current of an outdoor blower by constructing an air conditioner capable of cooling operation by annularly connecting a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger as a refrigeration cycle. And a comparison means for comparing the detected current and the set temperature, and the comparison result shows that the compressor operating frequency and the opening proportionality of the expansion valve are stepwise according to the change of the operating current at the same frequency. An expansion valve control device for an air conditioner, characterized by comprising expansion valve control means for changing and shifting in the opening direction. 7. A compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger are annularly connected as a refrigeration cycle to form an air conditioner capable of cooling operation, and heat is exchanged in the outdoor heat exchanger. Detecting means for detecting the temperature, comparing means for comparing the detected temperature with the set temperature, and the result of the comparison shows that the compressor operating frequency and the opening proportionality of the expansion valve are proportional to each other at the same frequency. An expansion valve control device for an air conditioner, which is provided with an expansion valve control means for performing a stepwise change according to a change in temperature and performing a shift change in an open compressor operating direction. 8. A detection means for detecting pressure from a pressure detector, which constitutes an air conditioner capable of cooling operation by annularly connecting a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger as a refrigeration cycle. And the comparison means for comparing the detected temperature with the set temperature, and the comparison result indicates that the compressor operating frequency and the expansion valve opening proportional relationship are changed to the change in the pressure detected by the pressure detection at the same frequency. An expansion valve control device for an air conditioner, which is provided with expansion valve control means for performing a stepwise change in accordance with a shift change in the opening direction.