JPS6287763A - Method of controlling refrigeration cycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] It's about good control methods.

[Conventional technology]

FIG. 4 is a diagram showing a conventional air conditioner refrigeration cycle that is effective for improving efficiency, as disclosed in, for example, Japanese Unexamined Patent Publication No. 58-15074. In the figure, (1) is a compressor, (2) is a condenser, (3) is a capillary throttle device, (4) is an evaporator, (5) is an accumulator, and (6) is a condenser.
is a solenoid valve 1 that prevents the refrigerant liquid in the condenser (2) and the cavity 21 (3) from flowing into the evaporator (4);
The circuit is open when No. 11 is in operation, and closed when it is stopped. (7) is a bypass that connects the discharge port and suction port of the compressor fl), and (8) is a solenoid valve installed in the bypass (7), which closes when the compressor +11 is in operation and opens when it stops. It looks like this. (9) is a check valve that prevents the flow of refrigerant from the condenser (2) side to the discharge port of the compressor (1).

In a refrigeration cycle configured in this way.

To explain the operation during cooling when the evaporator (4) is used as a heat exchanger on the heat utilization side, 2. During normal operation, solenoid valve 1 (6) is open, and '#L solenoid valve ■ (8) is closed. .

Now, when the indoor temperature falls below the set temperature, the compressor (1)
At the same time as stopping operation, solenoid valve 1 (6) is closed,
It confines the high-pressure refrigerant liquid in the condenser (2) between the check valve (9) and prevents heat loss caused by mixing with the low-temperature refrigerant in the evaporator (4). The circuit is opened and the compressor (1
) is equalized through the bypass (7) to reduce the load on the compressor (11) when restarting.It also prevents the refrigerant from returning to liquid when starting up the compression +* (tl). Not only can this be done, but the condenser (
2) The refrigerant liquid stored in is a solenoid valve! When the refrigerant (6) is opened, it flows into the evaporator (4) and evaporation of the refrigerant begins immediately, quickly cooling the room and increasing the efficiency of the refrigeration cycle.

[Problem that the invention seeks to solve]

The conventional refrigeration cycle configured as described above is an effective means of increasing the efficiency of the device, but in recent years.

The compressor (1) now performs capacity control by variable frequency, and an electric throttle device with a full opening function that integrates the conventional capillary (3) throttle device and solenoid valve I (6) is used as the throttle 9 device. FC has become popular. However, with this electric throttle device that has a fully closing function, it takes several seconds to go from fully open to fully closed, and when the compressor (1) is stopped, it takes a few seconds to go from the normal operating opening to fully open. A large amount of high-pressure refrigerant liquid from the condenser (2) side flows into the evaporator (4), weakening the conventional effect, and in order to obtain the conventional effect, the electric throttle is closed before the compressor (1) stops. When the device is fully closed.

A problem has arisen in that the separation pressure increases and has an adverse effect on the equipment.

This invention was made to solve the above-mentioned problems, and it is possible to maintain the efficiency of conventional refrigeration cycle equipment by changing the refrigeration cycle control method even in a refrigerant circuit using an electric throttling device. That's what I tried to do.

[Failure to solve the problem J A method for controlling a refrigeration cycle device according to the present invention is a method for controlling a refrigeration cycle device.

When the compressor (1) attempts to stop due to a temperature signal, etc.

The electric throttling device is operated to close, and the compressor (1) continues to operate until the opening is below a predetermined opening.

[Function J In this invention, an electric throttle device is used as a compressor filter.
It is sufficiently throttled before the compressor (1) stops, and even if the compressor (1) stops, it is quickly fully opened and the flow from the condenser (2) to the evaporator (4) is fully throttled.
Prevent the flow of refrigerant liquid to.

[Embodiment J Hereinafter, one embodiment of the present invention will be described with reference to the drawings. 1st
This figure shows a refrigeration cycle during cooling, and in this figure, the same reference numerals as in FIG. 4 are the same as or correspond to the conventional one in FIG. 4. [+1 is an electric throttle device driven by a stepping motor, etc. installed between the condenser (2) and the evaporator (4), and +lυ is a four-way valve that switches between cooling and heating (the figure shows cooling) ), α2 is the room temperature sensor, θJ is the signal from the room temperature sensor α, compressor il+, ' solenoid valve n (81,'
Electric throttle device (11, control circuit that controls the four-way valve 0υ).

In the refrigeration cycle control device αJ, which is an embodiment of the present invention configured as described above, as shown in the time chart of FIG. Temperature control signal α4 in the device urn
changes from ON to OFF. This @tonal signal α heart is OFF
Even if the compressor operation signal becomes OFF, the opening signal αS of the electronic throttle device first becomes in the closing direction, and the opening gradually closes.

Then, when the opening degree becomes below the predetermined opening determined at time b, the compressor operation signal no turns OFF, and the compressor (11
stops. At this time, the solenoid valve ■signal αD is turned ON, and the bypass (7) of the discharge port and suction port of the compressor (1) is turned on.
Open and balance low and high pressure. At time C, the electronic throttle device un is fully closed, and the refrigerant liquid can be trapped in the condenser (2) between it and the check valve (9).

Further, in the above embodiment, when the compressor fil is a variable frequency type (inverter) compressor.

As shown in the time chart shown in Fig. 3, when the temperature control signal α4 turns OFF at time d, the compressor operating signal (frequency) (IG becomes the lowest operating frequency, and the electronic throttle device opening signal a9 moves in the closing direction and gradually closes its opening.When the opening becomes fully closed at time e, the compressor operation signal (frequency) becomes OFF (OHz) and the compressor (1) stops. , the solenoid valve H signal αη turns ON, and the same effect as above can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, the compressor is stopped after the electric throttling device has sufficiently throttled the compressor, thereby preventing an abnormally high pressure from rising before the stop and immediately sealing the refrigerant in the condenser after the compressor is stopped. Because you can.

Even when an electric throttle device is used, the same effect as the conventional one can be obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a refrigeration cycle of an air conditioner according to an embodiment of the present invention, FIG. 2 is a time chart diagram showing a control method according to the embodiment of FIG. 1, and FIG. 3 is a diagram showing another embodiment of the present invention. FIG. 4 is a time chart diagram showing the control method according to the embodiment. FIG. 4 is a diagram showing the refrigeration cycle of a conventional air conditioner. (1) is a compressor, (2) is a condenser, (4) is an evaporator, H
(+31 is a control device. In Figure 7, the same reference numerals indicate the same - or corresponding parts.

Claims (2)

[Claims] (1) An electric throttle device with a full-closing function and a solenoid valve that opens and closes a bypass connecting the compressor discharge port and suction port;
and a refrigeration cycle in which a check valve is provided to prevent the flow of refrigerant from the condenser side to the discharge port of the compressor and the bypass to reduce heat loss due to operation and stop of the compressor, when the compressor stops. A method for controlling a refrigeration cycle, characterized in that the electric throttling device prohibits the compressor from stopping until the throttling amount (opening degree) becomes equal to or less than a predetermined throttling amount. (2) When the compressor is a frequency variable type (inverter) compressor, the compressor is stopped after the compressor is operated at the lowest frequency and the electric throttle device is completely closed. A method for controlling a refrigeration cycle according to item 1.