JPH09159292A - Controller for air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a change in resistance of a refrigerant passage and a rapid change in the resistance upon starting, and hence realize smooth starting. SOLUTION: Upon starting of cooling a refrigerant distribution motor driven expansion valve 9 is fully opened for a predetermined time. The amount of one time opening operation of the refrigerant distributing motor driven expansion valve 9 is specified, and once the opening is operated, the valve travel is kept for a predetermined time. Upon starting of heating a refrigerant flow rate adjusting motor driven expansion valve 10 is fully opened for a predetermined time, and then the control is changed to control with a temperature difference between a saturation temperature sensor and a suction temperature sensor. Further, upon starting of cooling and heating a solenoid valve 11 provided on a bypass circuit 7 is closed for a predetermined time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to control of an air conditioner.

[0002]

2. Description of the Related Art Conventionally, in an air conditioner equipped with an electric expansion valve of this type and a bypass circuit for detecting a saturation temperature,
The opening of the electric expansion valve for adjusting the refrigerant flow rate is controlled by the temperature difference between the saturation temperature sensor installed in the bypass circuit and the intake temperature sensor installed in the compressor intake passage to control the operating status of the indoor unit and the indoor air conditioning. It is known that the opening degree of an electric expansion valve for distributing refrigerant and the frequency of a compressor are uniquely changed according to a load.

[0003]

In the case of a so-called multi-type air conditioner in which the outdoor unit is large and there are many indoor units and the length of the connecting pipe is long, the refrigerant flow resistance of the connecting pipe and the pipe in the outdoor unit is large. large. Therefore, when the compressor is started from the compressor stopped state during cooling, the flow of the refrigerant is poor and the refrigerant does not return easily, the load on the compressor becomes large, and it takes time to stabilize the refrigeration cycle. Also, if the electric expansion valve for distributing refrigerant is changed from the fully opened state to the set opening degree according to the load at once, the electric expansion valve for adjusting the refrigerant flow rate reacts to changes in the refrigeration cycle, and the opening degree changes greatly. It takes time to return to the original opening. Similarly, when starting an outdoor unit with a bypass circuit for saturation temperature detection, if the refrigerant flow resistance to the connecting pipes or the outdoor heat exchanger is large, the refrigerant will flow to the bypass circuit and heat will not be sufficiently generated in the evaporator. It cannot be replaced and it takes time for the refrigeration cycle to stabilize.

In consideration of the above points, the present invention is to reduce the resistance of the refrigerant passage and the abrupt change of resistance at the time of starting to realize a smooth starting.

[0005]

In order to solve the above-mentioned problems, in the present invention, the electric expansion valve for distributing the refrigerant is fully opened for a certain period of time when the cooling is started. In addition, the amount of operation of the opening of the electric expansion valve for distributing the refrigerant was regulated, and once the opening was operated, the opening was maintained for a certain period of time. When the heating is started, the electric expansion valve for adjusting the refrigerant flow rate is fully opened for a certain period of time, and then the control is shifted to the control based on the temperature difference between the saturation temperature sensor and the suction temperature sensor. In addition, the solenoid valve provided on the bypass circuit was closed for a certain period of time both when cooling and when starting heating.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Since the refrigerant flows when the electric expansion valve for distributing the refrigerant is fully opened when the cooling is started, the refrigerant flow resistance on the indoor unit side is reduced as compared with the conventional indoor load control, and the refrigerant circulation amount is increased. Will speed up the stabilization.

Further, the opening of the electric expansion valve for distributing the refrigerant gradually shifts to the opening due to the conventional indoor load,
There is no sudden change in the refrigeration cycle, and the system enters a stable state smoothly.

Further, since the refrigerant flows with the electric expansion valve for adjusting the refrigerant flow rate fully opened when the heating is started, the refrigerant circulation amount on the evaporator side of the outdoor unit is controlled by the temperature difference between the conventional saturation temperature sensor and the suction temperature sensor. More than time, the time to stabilize is faster.

Further, since the refrigerant flows in a state where the bypass circuit is shut off at the time of starting cooling and heating, the bypass loss of the refrigerant is eliminated and the refrigerant circulation to the indoor unit and the outdoor unit increases,
The stabilization time of the refrigeration cycle is shortened.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of an embodiment of the present invention will be described with reference to FIG. An electric expansion valve 10 for adjusting the refrigerant flow rate and an electric expansion valve 9 for distributing the refrigerant are provided in the liquid side refrigerant passages of the outdoor unit 5 and the indoor unit 8.
Is provided. Further, a bypass circuit 7 is provided from the liquid side refrigerant passage to the suction passage of the compressor. In the bypass circuit 7, a solenoid valve 11 and a saturation temperature sensor 12 for detecting the saturation temperature of the low pressure side are provided in the suction passage of the compressor. Is provided with a suction temperature sensor 13. The electric expansion valve 9, the electric expansion valve 10 and the electromagnetic valve 11 are controlled by the first expansion valve control means, the second expansion valve control means and the electromagnetic valve control means, respectively, by signals from the electronic control unit 4.

Next, the operation contents during cooling will be described with reference to FIGS. First, when the cooling start signal is sent from the indoor unit 8 to the electronic control unit 4, the electronic control unit 4 sends a cooling start signal to the first expansion valve control means, and the first expansion valve control means causes the first expansion valve control means to perform the cooling operation. According to the control flow, the electric expansion valve 9 for distributing the refrigerant is held in a fully opened state. By the control, the refrigerant flow resistance to the indoor unit 8 is reduced as compared with the conventional control by the indoor load, and the flow rate of the refrigerant is increased. Therefore, the load on the compressor at the time of start-up is reduced and the time required for stabilization is shortened. Then, after the time T ₁ when the pressure becomes stable, the electric expansion valve 9 is returned to the conventional control by the indoor load, so that the proper refrigerant distribution becomes possible. FIG. 3 shows an operation example of the electric expansion valve 9 of the present invention and a conventional operation example.

Further, once the opening operation amount of the electric expansion valve 9 for distributing the refrigerant is regulated to P pulse and the fixed opening is operated, the opening is maintained for T ₂ seconds. The operation contents of the electric expansion valve 9 at this time will be described with reference to the control flow of FIG.
First, after the electric expansion valve 9 is held fully open for T ₁ second, the difference ΔT between the current opening and the target opening due to the indoor load is calculated. If there is P pulses or more, the P pulse is closed and T ₂ seconds are waited again. Take control action. If it is equal to or less than the P pulse, the difference ΔT between the present opening degree and the target opening degree due to the indoor load is closed. By the above control, it is possible to gradually shift to the target opening degree by P pulses. Therefore, the opening of the electric expansion valve 10 for adjusting the refrigerant flow rate does not change significantly in response to a sudden change in the refrigeration cycle, and the refrigeration cycle can be smoothly shifted to a stable state. FIG. 5 shows an operation example of the electric expansion valve 9 of the present invention and a conventional operation example.

Next, the operation contents during heating will be described with reference to FIGS. The electronic control unit 4 sends a heating start signal to the second expansion valve control means, and the second expansion valve control means holds the electric expansion valve 10 for adjusting the refrigerant flow rate in a fully opened state in accordance with the control flow during heating shown in FIG. To do. Due to the above control, the refrigerant flow resistance on the evaporator side of the outdoor unit 5 is reduced as compared with the conventional control by the temperature difference between the saturation temperature sensor 12 and the suction temperature sensor 13, so that the refrigerant flow rate to the evaporator is increased and the heat absorption amount is increased. Increases and the time to stabilize becomes faster. And T where the pressure is stable
After ₃ seconds, the electric expansion valve 10 for adjusting the refrigerant flow rate is returned to the conventional control based on the temperature difference between the saturation temperature sensor 12 and the suction temperature sensor 13. FIG. 7 shows an operation example of the electric expansion valve 10 of the present invention and a conventional operation example. Note that the purpose of the control based on the temperature difference between the saturation temperature sensor 12 and the suction temperature sensor 13 is to control the heating degree of the refrigerant on the suction side of the compressor, but the detailed content is omitted because it is different from the spirit of the present invention.

Next, the operation contents of the solenoid valve 11 provided in the bypass circuit 7 will be described with reference to FIGS. When a cooling or heating start signal is sent from the indoor unit 8 to the electronic control unit 4, the electronic control unit 4 sends a cooling or heating start signal to the solenoid valve control means 3, and the solenoid valve control means 3 electromagnetically follows the control flow of FIG. Close valve 11. Since the bypass circuit 7 is cut off by the control, the bypass loss of the liquid refrigerant through the bypass circuit 7 is eliminated, the refrigerant flow rate to the indoor unit 8 and the outdoor heat exchanger 6 is increased, and the stabilization time is shortened. Inhalation to the compressor can be reduced. Then, by opening the solenoid valve 11 after T ₄ when the pressure becomes stable, the saturation temperature can be detected and the refrigerant flow rate can be adjusted. FIG. 9 shows an operation example of the solenoid valve 11 of the present invention.

In the above embodiment, the case where the electric expansion valve 9 for distributing the refrigerant is independent has been described as an example, but a type in which the electric expansion valve 9 for distributing the refrigerant is housed in the outdoor unit and the indoor unit is explained. Needless to say, the same can be applied to the multi-type air conditioner having two or more air conditioners and indoor units.

[0016]

As is apparent from the above embodiments, according to the present invention, the refrigerant circulation resistance in the indoor side at the start of the cooling operation decreases, the refrigerant circulation amount increases, the stabilization time shortens, and the blowing of cold air is accelerated. At the same time, the reliability of the compressor is improved by reducing the load on the compressor.

Further, by rapidly changing the refrigerant flow resistance inside the room during the cooling operation, it is possible to prevent a sudden change in the refrigeration cycle and to smoothly shift to a stable state.

Further, the refrigerant circulation resistance on the side of the evaporator at the start of the heating operation is reduced, so that the refrigerant circulation amount is increased, the stabilization time is shortened, and the hot air is blown out faster.

Further, by closing the bypass circuit for a certain period of time after starting the cooling and heating operations, the bypass loss of the liquid refrigerant is eliminated, the stabilization time is shortened, and the suction of the liquid refrigerant to the compressor at the time of startup can be reduced.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle diagram according to one embodiment of the present invention.

FIG. 2 is a control system diagram in one embodiment of the present invention.

FIG. 3 is an operation graph of an electric expansion valve for distributing refrigerant according to an embodiment of the present invention and a conventional example.

FIG. 4 is a control system diagram in one embodiment of the present invention.

FIG. 5 is an operation graph of an electric expansion valve for distributing refrigerant according to an embodiment of the present invention and a conventional example.

FIG. 6 is a control system diagram in an embodiment of the present invention.

FIG. 7 is an operation graph of an electric expansion valve for adjusting a refrigerant flow rate according to an embodiment of the present invention and a conventional example.

FIG. 8 is a control system diagram in one embodiment of the present invention.

FIG. 9 is an operation graph of the solenoid valve according to the embodiment of the present invention.

[Explanation of symbols]

 1 expansion valve control means 2 expansion valve control means 3 solenoid valve control means 4 electronic control unit 5 outdoor unit 6 outdoor heat exchanger 7 bypass circuit 8 indoor unit 9 electric expansion valve 10 electric expansion valve 11 electromagnetic valve

Claims (4)

[Claims] 1. An electronic control unit for providing a plurality of electric expansion valves for distributing a refrigerant in a liquid side refrigerant passage between an outdoor heat exchanger and a plurality of indoor units, and for processing a signal from the indoor unit. A first expansion valve control means for controlling the opening degree of the electric expansion valve for distributing the refrigerant is provided to receive a signal from the electronic control unit, and the electric expansion valve for distributing the refrigerant for a certain period of time after a cooling operation is started. A control device for an air conditioner, which is characterized in that the opening of the air conditioner is fully opened. 2. The air conditioner according to claim 1, wherein the electric expansion valve for distributing the refrigerant defines a single opening operation amount and holds the opening for a certain period of time once the opening is operated. Machine control device. 3. An electric expansion valve for adjusting a refrigerant flow rate is provided between the liquid side refrigerant passage of the outdoor unit and a suction passage of the compressor, the bypass circuit for detecting a saturation temperature is provided between the bypass circuit and the outdoor heat exchanger. And a second expansion valve control means for controlling the opening degree of the electric expansion valve for adjusting the refrigerant flow rate for receiving the signal from the electronic control unit, and for adjusting the refrigerant flow rate for a certain period of time after starting the heating operation. The air conditioner control device having the characteristic that the opening degree of the electric expansion valve is fully opened. 4. A solenoid valve is provided in a saturation temperature detecting bypass circuit, and a solenoid valve control means is provided for controlling opening and closing of the solenoid valve by receiving a signal from an electronic control unit, and after cooling and heating operations are started. An air conditioner control device characterized in that the solenoid valve is closed for a certain period of time.