JPH04124545A - Electric expansion valve control method for air conditioner - Google Patents

Abstract

PURPOSE:To eliminate the condition in which all indoor electric expansion valves are fully closed, thereby stable operation control being ensured, by checking that at least one electric expansion valve is not fully closed before the electric expansion valve of each indoor unit is fully closed. CONSTITUTION:Assume that all indoor units 2a, 2b are in cooling operation. When the operation of one indoor unit 2b stops, a fully closing control means 16b judges from the communication data of indoor transmission means 15a, 15b whether all electric expansion valves of another indoor unit 2a are fully closed or not. When even one electric expansion valve 9a is not fully closed in another indoor unit 2a as a result of this judgment, the fully closing control means 16b tells to a valve opening control means 13b that the electric expansion valve 9b is to be closed. The valve opening control means 13b fully closes the electric expansion valve 9b. Next, the indoor unit 2a in operation is stopped by a line 21. Since all electric expansion valves 9b of another indoor unit 2b are fully closed, an electric expansion valve 9a is not fully closed, and a compressor 3 is stopped.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an electric expansion valve control method for an indoor unit of an air conditioner in which a plurality of indoor units are connected to one outdoor unit. .

BACKGROUND OF THE INVENTION A conventional electric expansion valve control method for an air conditioner in which a plurality of indoor units are connected to one outdoor unit will be described with reference to the drawings.

Figure 3 is a refrigerant piping system diagram, where 1 is the outdoor unit and 2a is the outdoor unit.
, 2b is an indoor unit. The outdoor unit 1 mainly includes a compressor 3, an inverter 4 that changes the frequency to adjust the capacity of the compressor, a four-way valve 5 that switches the flow of refrigerant, an accumulator 6, and an outdoor heat exchanger 7. As for the equipment, indoor heat exchangers 8a and 8b and indoor electric expansion valves 9a and 9b are respectively installed in the indoor units 2a and 2b as main equipment, and each of the above-mentioned main equipment is connected to each other by a refrigerant pipe 1o. has been done.

FIG. 4 is a control circuit configuration diagram of the conventional air conditioner, in which the outdoor unit 1 includes a compressor 3, an inverter 4 that adjusts the capacity by varying the operating frequency of the compressor 3, and an outdoor transmission means 11.
However, the indoor units 2a and 2b have indoor transmission means 12a and 12b.
, indoor electric expansion valves 9a and 9b that control the flow rate of refrigerant, and valve opening control means 13a and 13b that control the opening degrees of the electric expansion valves 9a and 9b to predetermined valve openings, and set the operating state. Remote control switches 14a and 14b are connected.

The operation of the air conditioner configured as above will be explained below.

Now, the indoor units 2a and 2b are connected to the remote control switch 14a.

It is assumed that the indoor unit 2b is in the cooling operation state by the remote control switch 14b, and then the operation state of the indoor unit 2b is changed to the stopped state by the remote control switch 14b. At this time, the electric expansion valve 9b of the indoor unit 2b is brought into a fully closed state by the valve opening control means 13b. When this state occurs, the refrigerant is transferred from the compressor 3 to the four-way valve 5.
It circulates with the outdoor heat exchanger 7, passes through the electric expansion valve 9a of the indoor unit through the refrigerant piping 1o, is heat exchanged with the indoor heat exchanger 8a, passes through the four-way valve 6, the accumulator 6, and the compressor 3.
, and the water does not flow to the indoor unit 2b.

Further, when the indoor unit 2a is brought into a stopped state by the remote control switch 14a, the electric expansion valve 9a of the indoor unit 2a is brought into a fully closed state by the valve opening means 13a, and the compressor 3 is brought into a stopped state. becomes.

Incidentally, as shown in this conventional example, an air conditioner is known that is equipped with an inverter, a compressor, and an electric expansion valve to perform capacity control (Japanese Unexamined Patent Publication No. 58-205057).
.

Problems to be Solved by the Invention However, in conventional electric expansion valve control for indoor units, each indoor unit controls the electric expansion valves of other indoor units independently of the opening degree and the operating state of the compressor of the outdoor unit. Therefore, due to transmission delays, inverter stop delays, etc., the electric expansion valves of all indoor units may become fully closed even though the compressor is in operation, resulting in an abnormal rise in pressure within the refrigeration system. This will not only cause the equipment's protection device to activate and stop it, but also
This had problems such as shortening the life of the equipment.

The present invention solves the conventional problems, and an object of the present invention is to provide a control method for electric expansion valves that eliminates a situation in which a compressor is operating while the electric expansion valves of all indoor units are fully closed. .

Means for Solving the Problems To achieve this object, the electric expansion valve control method of the present invention includes an outdoor transmission means for the outdoor unit, an indoor transmission means and a fully closed control means for the indoor unit, and a control method for each indoor unit. The transmission means reads the opening degrees of the electric expansion valves of other indoor units, and the fully-closed control means determines whether to fully close the electric expansion valves.

Effect: With the above configuration, when each indoor unit brings the electric expansion valve into the fully closed state, it is determined from the communication data with each indoor transmission means that at least one electric expansion valve of the other indoor units is not fully closed. The fully closed control means determines to fully close the valve after confirming the following. As a result, the electric expansion valves of all the indoor units are not completely closed, and the pressure inside the refrigeration system 7 does not increase, making stable operation control possible.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

The refrigerant piping system is the same as the conventional configuration shown in FIG. 3, and the circuit configurations in FIG. 1 that are the same as those in the conventional configuration shown in FIG.

FIG. 1 shows a circuit configuration of an air conditioner according to an embodiment of the present invention. Outdoor unit 1. Compressor 3. Inverter 4. The outdoor transmission means 11 is the same as the conventional one, and the indoor units 2a and 2b include a means for communicating between the outdoors and each room, and an indoor transmission means 15.
a, 1sb, indoor electric expansion valves sa, 9b that control the flow rate of refrigerant, and valve opening degree control means 13a, 13 that control the opening degrees of the electric expansion valves 9a, sb to predetermined valve opening degrees.
b, and an indoor electric expansion valve 9a connected to the indoor transmission means 15a, 16b and the valve opening control means 13a, 13b.
.

Fully closed control means 16a, 16b for determining whether or not 9b is fully closed;
A remote controller 14a for setting the operating state.

14b is connected.

Next, the operation of this embodiment will be explained with reference to the flowchart shown in FIG.

Assume that all the indoor units 2a and 2b are now in the cooling operation state. After that, when one of the indoor units 2b enters the operation stop state 18 due to the control switch 14b, a judgment 19 as to whether all the electric expansion valves of the other indoor units 2a are fully closed is made from the communication data of the indoor transmission means 15a and 16b. This is performed by the closing control means 16b. In this judgment 19, one of the other indoor units 2a
If the electric expansion valve 9a is not fully closed in the case of No, the full-close control means 16b notifies the valve opening degree control means 13b that the electric expansion valve 9b is to be fully closed, and the valve opening degree control means 13b The valve 9b is fully closed 20 degrees.Next, the indoor unit 2a, which is currently in operation via the line 21, is brought to a stop state 18 using the remote control switch 14a. In judgment 19, all the electric expansion valves 9b of the other indoor units 2b are fully closed (Yes), so the fully closed control means 16a transmits the fully closed signal to the valve opening control means 1.
It is not sent to 3M, the electric expansion valve 9 & is not fully closed (22), and the compressor 3 is stopped (23).

The above control prevents the electric expansion valves 9a and 9b of all indoor units 2a and 2b from becoming fully closed even though the compressor 3 is in operation due to transmission delays, stop delay time of the inverter 4, etc. This causes an abnormal increase in pressure within the refrigeration system.

Effects of the Invention As described above, the present invention is an air conditioner in which a plurality of indoor units are connected to one outdoor unit, and the outdoor unit is connected to an outdoor transmission means, and the indoor unit is connected to an indoor transmission means. Equipped with a control means, when each indoor unit fully closes the electric expansion valve,
After the fully closed control means confirms from the communication data between the outdoor transmission means and the indoor transmission means of each indoor unit that the electric expansion valve of at least one of the other indoor units is not in a fully closed state, the valve opening degree control means By fully closing the electric expansion valve, the pressure within the refrigeration system does not increase, making stable operation control possible and preventing a reduction in the life of the equipment.

[Brief explanation of drawings]

Fig. 1 is a control circuit configuration diagram of an air conditioner according to an embodiment of the present invention, Fig. 2 is a flowchart showing control details of the present invention, and Fig. 3 is a conventional air conditioner ≠ an air conditioner according to an embodiment of the present invention. FIG. 4 is a control circuit configuration diagram of a conventional air conditioner. 1...Outdoor unit, 2a, 2b...Indoor unit, 3...Compressor, 9a, 9b...Electric expansion valve, 13a. 13b...Valve opening control means, 16a, 16
b...Fully closed control means. Name of agent: Patent attorney Akira Fukuji et al.

Claims (1)

[Claims] An outdoor unit that has an outdoor transmission means and a compressor for communicating with multiple indoor units, an indoor transmission means for communicating with this outdoor unit and other indoor units, and an electric expansion that controls the flow rate of refrigerant. The transmission means includes a valve, a valve opening control means for controlling the electric expansion valve, and a fully closing control means for determining whether the electric expansion valve is fully closed, and the outdoor unit and the plurality of indoor units are connected to each transmission means. When the indoor unit fully closes the electric expansion valve depending on the operating state, the fully closed control means determines whether the other An electric expansion valve for an air conditioner, wherein after confirming that at least one electric expansion valve of the indoor unit is not fully closed, the valve opening degree control means performs a fully closing operation of the electric expansion valve. Control method.