JP2003287312A - Device and method for controlling expansion valve of multi-room type air-conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expansion valve control device of a multi-chamber type air-conditioner for collecting refrigerating machine oil discharged from a compressor without allowing the refrigerating machine oil to stay in a stopped indoor unit when the compressor is started in the heating operation with the stopped indoor unit present therein, and ensuring the refrigerating machine oil of the amount sufficient for not causing troubles of the compressor. <P>SOLUTION: This expansion valve comprises a means for setting the opening of an electric-driven expansion valve to control the refrigerant flow rate of the stopped indoor unit when the compressor is started, a refrigerating machine oil take-out quantity determining means to determine whether or not the take- out quantity of the refrigerating machine oil from the compressor is large based on the shell temperature of the compressor, and an electric-driven expansion valve opening correcting means to maintain the opening of the electric-driven expansion valve if the take-out quantity of the refrigerating machine oil is determined to be larger by this refrigerating machine oil take-out determining means. The refrigerating machine oil discharged from the compressor can be collected thereby. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a plurality of heat exchangers, and an expansion valve control for a multi-chamber air conditioner having a throttle mechanism for adjusting the flow rate of refrigerant flowing through the heat exchangers. The present invention relates to a device and a control method.

[0002]

2. Description of the Related Art FIG. 10 shows, for example, Japanese Patent Laid-Open No. 11-2646.
FIG. 10 is a system configuration diagram showing an expansion valve control device of a conventional multi-room air conditioner disclosed in Japanese Patent Publication No. 20-52. In the figure,
An outdoor unit 1 includes a compressor 4 that compresses a refrigerant, a four-way valve 5 that switches the flow of the refrigerant, an outdoor heat exchanger 6, and electric expansion valves 7 and 8. 2 is an indoor unit A, 3 is an indoor unit B,
Each has an indoor unit A heat exchanger 9 and an indoor unit B heat exchanger 10. The indoor unit A heat exchanger 9 is connected to the indoor unit A electric expansion valve 7, and the indoor unit B heat exchanger 10 is connected to the indoor unit B3 electric expansion valve 8.

Reference numeral 11 denotes an outdoor heat exchanger temperature detecting means mounted on the outdoor heat exchanger 6 for detecting the temperature of the outdoor heat exchanger 6, and 12 denotes a refrigerant shortage based on an output result of the outdoor heat exchanger temperature detecting means 11. Refrigerant pooling determination means for determining that the state is set to 13, 13 is an electric expansion valve for indoor unit A that is stopped based on the output result of the coolant pooling determination means.
The electric expansion valve opening correction means for correcting and adjusting the opening of the electric expansion valve.

Here, the structure is taken up as an example of a two-chamber type, but in a type such as a three-chamber type and a four-chamber type to which more indoor units are connected, the indoor heat exchanger has a structure correspondingly. Will increase.

Next, the operation will be described. As for the flow of the refrigerant, the refrigerant discharged from the compressor 4 during cooling is
After passing through the four-way valve 5 to the side of the outdoor heat exchanger 6 and condensed there, it branches to the electric expansion valve 7 for the indoor unit A and the indoor unit B.
Flow to the electric expansion valve 8 for use. The refrigerant decompressed by the electric expansion valve 7 for the indoor unit A goes to the indoor unit A heat exchanger 9, the refrigerant decompressed by the electric expansion valve 8 for the indoor unit B goes to the indoor unit B heat exchanger 10, and then merges. , And returns to the compressor 4 via the four-way valve 5.

During heating, the refrigerant discharged from the compressor 4 passes through the four-way valve 5 and then branches to the indoor unit A heat exchanger 9 to the indoor unit A electric expansion valve 7 and the indoor unit B heat exchange. After going from the device 10 to the electric expansion valve 8 for the indoor unit B and joining, the flow returns to the compressor 4 via the outdoor heat exchanger 6 and the four-way valve 5.

Here, as can be seen from the circuit configuration,
Since it is not necessary to flow the refrigerant to either the indoor unit A2 chamber or the indoor unit B3 chamber that is not operating, the electric expansion valve opening on the stop side should be fully closed, but in the circuit as shown in FIG. Since there is an electric expansion valve on the inlet side (outlet side in the heating circuit) of the cooling circuit of the indoor heat exchanger, it can be fully closed in the cooling circuit as it is, but in the heating circuit, when it is fully closed, the stop side indoor unit Since the refrigerant accumulates in the refrigerant and the refrigerant becomes insufficient, the electric expansion valve is slightly opened to prevent the refrigerant from leaking so that the refrigerant does not accumulate.

However, since the electric expansion valve of the indoor unit on the stop side cannot be opened very slightly to suppress the decrease in capacity, a certain amount of refrigerant is always accumulated in the indoor unit on the stop side. At this time, a certain amount of refrigerating machine oil taken out together with the refrigerant also accumulates in the stop side indoor unit, which causes a failure of the compressor 4.

Therefore, during the heating operation, based on the output result of the outdoor heat exchanger temperature detecting means 11, the refrigerant accumulation judging means 12 judges whether the refrigerant has accumulated in the stop side indoor unit A2, and the refrigerant accumulates. When it is determined that the stop side indoor unit A2 is determined by the electric expansion valve opening correction unit 13.
The expansion valve opening of is adjusted to prevent refrigerant accumulation.

Also, the compressor operation / stop time is measured for each indoor unit, and when the set time is integrated, the valve is "open" and "closed".
Japanese Patent Application Laid-Open No. 02-044157 discloses a technique of issuing a command and collecting the retained refrigerant and the refrigerating machine oil in a compressor.

[0011]

Since the conventional expansion valve control device for a multi-room air conditioner is configured as described above, when there is a stopped indoor unit during heating operation, outdoor heat exchange during operation is performed. Accumulation of refrigerant and refrigerating machine oil in the stop side indoor unit is detected by integrating the unit temperature and the off side indoor unit off time, and the opening of the electric expansion valve is adjusted to collect in the stop side indoor unit. Therefore, it is impossible to prevent the accumulation of refrigerating machine oil in the stop side indoor unit when starting the compressor, which is the one that most often takes out refrigerating machine oil, and secure the necessary amount of refrigerating machine oil to ensure the quality of the compressor. There was a problem that I could not.

The present invention has been made to solve the above problems, and when the compressor is started in the heating operation in which the stopped indoor unit exists, the compressor oil does not stay in the stopped indoor unit and is compressed. It is an object of the present invention to provide an expansion valve control device and control method for a multi-chamber air conditioner that can collect refrigerating machine oil discharged from a compressor and can secure a sufficient amount of refrigerating machine oil to prevent a compressor from malfunctioning. And

[0013]

An expansion valve control device for a multi-room air conditioner according to the present invention is provided with a plurality of indoor units and a plurality of electric expansion valves for controlling the refrigerant flow rate of each indoor unit. In a multi-room air conditioner having two outdoor units, during the heating operation with the stopped indoor unit, the opening degree of the electric expansion valve that controls the refrigerant flow rate of the stopped indoor unit from the start of the compressor to a predetermined opening degree. A larger setting means, a refrigerating machine oil take-out judging means for judging whether or not the refrigerating machine oil carry-out quantity from the compressor is large based on the compressor shell temperature, and a large amount of refrigerating machine oil carry-out by the refrigerating machine oil take-out judging means. When it is determined that the refrigerating machine oil discharged from the compressor is provided with an electric expansion valve opening correction means for maintaining the opening of the electric expansion valve.

Further, in the expansion valve control device for a multi-room air conditioner according to the present invention, the refrigerating machine oil take-out determining means has a large take-out amount of refrigerating machine oil from the compressor when the compressor shell temperature is low, When the machine shell temperature is high, it is determined that the taken-out amount of the refrigerating machine oil from the compressor is small.

Further, the expansion valve control device for a multi-room air conditioner according to the present invention is characterized in that the refrigerating machine oil take-out judging means is used.
When the amount of refrigerating machine oil taken out from the compressor is small, that is, when the compressor shell temperature is higher than a predetermined value, the electric expansion valve opening degree of the stopped indoor unit is returned to the predetermined opening degree.

Further, the expansion valve control device for a multi-room air conditioner according to the present invention is provided with a necessary compressor operating time calculating means for judging whether or not a necessary time for refrigerating machine oil recovery has elapsed, and a refrigerating machine oil take-out judging means. Therefore, even when it is determined that the amount of refrigerating machine oil taken out is small, the required compressor operating time calculation means calculates the operating time from the start of the compressor, and the opening degree of the electric expansion valve opening degree is calculated until a predetermined time elapses. By maintaining
It is characterized in that the refrigerating machine oil accumulated in the stopped indoor unit is recovered by the compressor.

Further, in the expansion valve control device for a multi-room air conditioner according to the present invention, when the predetermined time has passed by the required compressor operating time calculation means, the electric expansion valve of the stopped indoor unit is opened. The feature is that the degree is returned to a predetermined opening degree.

Further, the expansion valve control device for a multi-room air conditioner according to the present invention is provided with a stop indoor unit capacity determining means for determining the capacity of the stop indoor unit, and
It is characterized in that the opening degree of the electric expansion valve of the stopped indoor unit is determined.

An expansion valve control method for a multi-room air conditioner according to the present invention comprises a plurality of indoor units and one outdoor unit equipped with a plurality of electric expansion valves for controlling the refrigerant flow rate of each indoor unit. In a multi-room air conditioner having, in heating operation with a stopped indoor unit, from the time of starting the compressor, a step of setting the opening of the electric expansion valve for controlling the refrigerant flow rate of the stopped indoor unit to be larger than a predetermined opening, A step of determining whether or not the amount of refrigerating machine oil carried out from the compressor is large based on the compressor shell temperature;
When it is determined that the amount of refrigerating machine oil taken out is large, a step of maintaining the opening degree of the electric expansion valve is included, and the refrigerating machine oil discharged from the compressor is recovered.

Further, in the expansion valve control method for a multi-room air conditioner according to the present invention, the amount of refrigerating machine oil taken out is determined by determining the amount of refrigerating machine oil taken out from the compressor when the compressor shell temperature is low. It is characterized in that it is determined that the amount of refrigerating machine oil carried out from the compressor is small when the compressor shell temperature is high.

Further, the expansion valve control method for a multi-room air conditioner according to the present invention determines the refrigerating machine oil carry-out amount,
When the amount of refrigerating machine oil taken out from the compressor is small, that is, when the compressor shell temperature is higher than a predetermined value, the electric expansion valve opening degree of the stopped indoor unit is returned to the predetermined opening degree.

Further, according to the expansion valve control method for a multi-chamber air conditioner according to the present invention, even when it is judged that the amount of refrigerating machine oil taken out from the compressor is small based on the compressor shell temperature, the refrigerating machine oil is recovered. Judge whether the required time of has passed,
By maintaining the opening degree of the electric expansion valve until a predetermined time elapses, the refrigerating machine oil accumulated in the stopped indoor unit is recovered in the compressor.

Further, in the expansion valve control method for a multi-chamber air conditioner according to the present invention, when the predetermined time for refrigerating machine oil recovery has elapsed, the electric expansion valve opening degree of the stopped indoor unit is changed to the predetermined opening degree. It is characterized by returning to.

In the expansion valve control method for a multi-room air conditioner according to the present invention, the capacity of the stopped indoor unit is determined, and the electric expansion valve opening degree of the stopped indoor unit is determined based on the capacity of the stopped indoor unit. It is characterized by

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1. 1 to 3 are views showing the first embodiment, FIG. 1 is a system configuration diagram showing an expansion valve control device of a multi-room air conditioner, and FIG. 2 is a relational diagram of compressor shell temperature and refrigerator oil carry-out amount, FIG. 3 is a control flowchart showing the operation contents.

In FIG. 1, reference numeral 1 is an outdoor unit, a compressor 4 for compressing a refrigerant, a four-way valve 5 for switching the flow of the refrigerant,
Outdoor heat exchanger 6, electric expansion valve 7 for indoor unit A, indoor unit B
And an electric expansion valve 8 for the vehicle. Reference numeral 2 is an indoor unit A, 3 is an indoor unit B, each having an indoor unit A heat exchanger 9 and an indoor unit B heat exchanger 10. Then, the indoor unit A heat exchanger 9 is connected to the indoor unit A
The electric expansion valve 7 for indoor unit B and the electric expansion valve 8 for indoor unit B are connected to the indoor unit B heat exchanger 10.

Further, 14 is a compressor shell temperature detecting means for detecting the shell temperature of the compressor 4, and 15 is a judgment on the basis of the output of the compressor shell temperature detecting means 14 whether or not the taken-out amount of the refrigerating machine oil is large. The refrigerating machine oil take-out determination means 13 is based on the refrigerating machine oil take-out determination means 15 and is electrically connected to the indoor unit A9 which is the stopped indoor unit and corrects the opening degree of the electric expansion valve 7 for the indoor unit A. It is an electric expansion valve opening correction means for adjusting.

Here, the refrigerating machine oil carry-out judging means 15 will be described with reference to FIG. 2 as to how the refrigerating machine oil carry-out is judged according to the compressor shell temperature. As shown in the figure, the carry-out amount of the refrigerating machine oil from the compressor 4 increases as the compressor shell temperature decreases, and decreases as the compressor shell temperature increases. Therefore, by detecting the compressor shell temperature from the time of starting the compressor, it can be determined that the amount of refrigerating machine oil taken out from the compressor 4 has decreased.

Thus, when the compressor shell temperature is low at the time of starting the compressor, it is determined that the amount of refrigerating machine oil taken out from the compressor 4 is large, and the opening degree of the electric expansion valve 7 for the stopped indoor unit A is set. By opening from the predetermined opening degree, the refrigerating machine oil accumulated in the stopped indoor unit A2 is reduced, and the refrigerating machine oil taken out from the compressor 4 is collected in the compressor 4.

Next, the operation will be described with reference to the flowchart of FIG. First, in step S1, the compressor 4 is started by operating one heating unit. In step S2, the electric expansion valve opening degree of the stopped indoor unit is set to be larger than a predetermined opening degree. In step 3, it is determined whether the compressor shell temperature is higher than a predetermined value X ° C. When the compressor shell temperature is equal to or lower than the predetermined value X ° C., the process returns to step S2 and the electric expansion valve opening degree of the stopped indoor unit is set to be larger than the predetermined opening degree. When the compressor shell temperature is higher than the predetermined value X ° C., the electric expansion valve opening degree of the stopped indoor unit is returned to the predetermined opening degree in step S4.

Here, the electric expansion valve opening of the stopped indoor unit opened to a larger opening than the predetermined opening is returned to the predetermined opening to open the electric expansion valve opening of the stopped indoor unit larger than the predetermined opening. It is possible to prevent the heat radiation loss that occurs when the temperature is set to a certain value.

According to the above-described embodiment, in the heating operation with the stopped indoor unit, the opening degree of the electric expansion valve for controlling the refrigerant flow rate of the stopped indoor unit is set to be larger than the predetermined opening degree from the start of the compressor. When the refrigerating machine oil take-out judging means 15 for judging whether or not the refrigerating machine oil take-out quantity from the compressor 4 is large based on the compressor shell temperature, when the refrigerating machine oil take-out quantity is judged to be large, the opening degree thereof should be maintained. so,
Refrigerator oil is prevented from accumulating in the stopped indoor unit, and the compressor 4
Refrigerator oil discharged from the compressor 4 can be recovered.
Has the effect of securing a sufficient amount of refrigerating machine oil so as not to cause a breakdown.

Embodiment 2. 4 to 6 are views showing the second embodiment, FIG. 4 is a system configuration diagram showing an expansion valve control device of a multi-room air conditioner, and FIG. 5 is an electric expansion valve opening degree of a stopped indoor unit and a stopped indoor unit. Diagram of the amount of refrigerating machine oil collected from
FIG. 6 is a control flow chart showing the operation contents.

FIG. 4 shows a system configuration of FIG. 1 shown in the first embodiment, in which a necessary compressor operating time calculating means 16 for determining whether or not a required time for refrigerating machine oil recovery has elapsed is added.

FIG. 5 shows the relationship between the time required to maintain the electric expansion valve of the stopped indoor unit larger than a predetermined opening and the amount of refrigerating machine oil collected in the stopped indoor unit, which is determined by a test. . As shown in the figure, if the time period in which the electric expansion valve opening degree of the stopped indoor unit is kept larger than the predetermined opening degree is long, a large amount of refrigerating machine oil accumulated in the stopped indoor unit can be collected. Therefore, by the time to maintain the electric expansion valve opening of the stopped indoor unit at an opening larger than the predetermined opening,
It is possible to judge how much refrigerating machine oil accumulated in the stopped indoor unit can be collected.

Thus, the refrigerating machine oil carry-out determination means 1
Even when the determination of 5 indicates that the amount of refrigerating machine oil taken out from the compressor 4 is reduced, when the necessary compressor operating time calculating means 16 determines that the refrigerating machine oil accumulated in the stopped indoor unit is insufficiently collected. By setting the electric expansion valve opening of the stopped indoor unit to a value larger than the specified opening until that time is sufficient, the refrigeration oil accumulated in the stopped indoor unit can be reliably collected, which is necessary for ensuring compressor quality. Refrigerating machine oil can be collected in the compressor 4.

Next, the operation will be described with reference to the flowchart of FIG. First, in step S1, the compressor 4 is started by operating one heating unit. In step S2, the electric expansion valve opening degree of the stopped indoor unit is set to be larger than a predetermined opening degree. In step 3, it is determined whether the compressor shell temperature is higher than a predetermined value X ° C. When the compressor shell temperature is equal to or lower than the predetermined value X ° C., the process returns to step S2 and the electric expansion valve opening degree of the stopped indoor unit is set to be larger than the predetermined opening degree. Compressor shell temperature is a predetermined value X
If the temperature is higher than ° C, the process proceeds to step S5. Step S5
When the required operation time is Y minutes or less, the process returns to step S2 and the electric expansion valve opening degree of the stopped indoor unit is set to be larger than the predetermined opening degree. If it has been more than Y minutes, the process proceeds to step 4 to return the electric expansion valve opening degree of the stopped indoor unit to the predetermined opening degree.

Here, the electric expansion valve opening of the stopped indoor unit which is opened to a larger opening than the predetermined opening is returned to the predetermined opening to open the electric expansion valve opening of the stopped indoor unit to a larger opening than the predetermined opening. It is possible to prevent the heat radiation loss that occurs when the temperature is set to a certain value.

According to the above-described embodiment, since the refrigerating machine oil carry-out judging means 15 is provided with the necessary compressor operating time calculating means 16 for judging whether or not the necessary time for refrigerating machine oil recovery has passed, the stop chamber is stopped. The refrigerating machine oil accumulated in the machine can be reliably collected in the compressor 4.

Embodiment 3. 7 to 9 are views showing the third embodiment, FIG. 7 is a system configuration diagram showing an expansion valve control device of a multi-room air conditioner, and FIG. 8 is a volume of the stopped indoor unit and a trap in the stopped indoor unit. FIG. 9 is a control flow chart showing the operation contents of the electric expansion valve opening required for prevention.

FIG. 7 shows a system configuration of FIG. 4 shown in the second embodiment with a stopped indoor unit capacity determining means 17 added.

FIG. 7 shows the relationship between the volume of the stopped indoor unit and the opening degree of the electric expansion valve required to collect the refrigerant accumulated in the stopped indoor unit. As shown in the figure, if the volume of the stopped indoor unit is large, it is necessary to set the electric expansion valve opening degree of the stopped indoor unit large. Therefore, it is possible to determine how to set the electric expansion valve opening degree of the stopped indoor unit based on the volume of the stopped indoor unit.

Thus, by determining the volume of the stopped indoor unit, it is possible to determine the opening degree of the electric expansion valve required for the refrigerant not to accumulate in the stopped indoor unit, and to stop regardless of the volume of the stopped indoor unit. The refrigerating machine oil accumulated in the indoor unit can be surely recovered, and the refrigerating machine oil necessary for ensuring the compressor quality can be recovered in the compressor.

Next, the operation will be described with reference to the flowchart of FIG. First, in step S1, the compressor is started by operating one heater. In step S6, it is determined to what extent the electric expansion valve opening degree of the stopped indoor unit is made larger than a predetermined opening degree by the volume of the stopped indoor unit, and is set to that opening degree. In step 3, it is determined whether the compressor shell temperature is higher than a predetermined value X ° C. When the compressor shell temperature is equal to or lower than the predetermined value X ° C, the process returns to step S6. Compressor shell temperature is a predetermined value X
If the temperature is higher than ° C, the process proceeds to step S5. Step S5
If the required operating time is Y minutes or less, the process returns to step S6. Step 4 if Y minutes have passed
Then, the opening degree of the electric expansion valve of the stopped indoor unit is returned to the predetermined opening degree.

Here, the electric expansion valve opening of the stopped indoor unit which is opened to a larger opening than the predetermined opening is returned to the predetermined opening to open the electric expansion valve opening of the stopped indoor unit to a larger opening than the predetermined opening. It is possible to prevent the heat radiation loss that occurs when the temperature is set to a certain value.

According to the above-described embodiment, by providing the stopped indoor unit capacity determining means 17 for determining the capacity of the stopped indoor unit, the optimal electric expansion valve for the stopped indoor unit in which refrigerating machine oil in the stopped indoor unit does not stay. Since the opening can be determined, the refrigerating machine oil accumulated in the stopped indoor unit can be reliably collected in the compressor even when an indoor unit of any volume is connected.

[0047]

The expansion valve control device for a multi-room air conditioner according to the present invention, in the heating operation with a stopped indoor unit,
From the time of starting the compressor, means for setting the opening degree of the electric expansion valve for controlling the refrigerant flow rate of the stopped indoor unit to be larger than a predetermined opening degree,
Refrigerator oil take-out determination means for determining whether the taken-out amount of refrigerating machine oil from the compressor is large based on the compressor shell temperature, and if it is determined that the taken-out amount of refrigerating machine oil is large by this refrigerating machine oil taking-out determination means, An electric expansion valve opening correction means for maintaining the opening of the electric expansion valve is provided, and when the refrigerating machine oil discharged from the compressor is collected, the opening degree of the refrigerating machine oil is adjusted when it is determined that the taken-out amount of the refrigerating machine oil is large. By maintaining it, it is possible to prevent refrigerating machine oil from accumulating in the stopped indoor unit, to collect refrigerating machine oil discharged from the compressor, and to secure a sufficient amount of refrigerating machine oil so that the compressor does not malfunction. is there.

Further, in the expansion valve control device for a multi-chamber air conditioner according to the present invention, the refrigerating machine oil take-out determining means has a large take-out amount of refrigerating machine oil from the compressor when the compressor shell temperature is low, By determining that the amount of refrigerating machine oil carried out from the compressor is small when the machine shell temperature is high, it is possible to determine the amount of refrigerating machine oil carried out only by detecting the compressor shell temperature.

Further, the expansion valve control device for a multi-chamber air conditioner according to the present invention uses the refrigerating machine oil carry-out judging means.
When the amount of refrigerating machine oil taken out from the compressor is small, that is, when the compressor shell temperature is higher than a predetermined value, by returning the electric expansion valve opening degree of the stopped indoor unit to the predetermined opening degree, it is taken out at the time of starting the compressor. The refrigerating machine oil can be reliably collected,
There is an effect that it is possible to prevent heat loss caused by making the electric expansion valve of the stopped indoor unit larger than a predetermined opening.

Further, the expansion valve control device for a multi-chamber air conditioner according to the present invention is provided with a necessary compressor operating time calculating means for judging whether or not a necessary time for refrigerating machine oil recovery has elapsed, and a refrigerating machine oil take-out judging means. Therefore, even when it is determined that the amount of refrigerating machine oil taken out is small, the required compressor operating time calculation means calculates the operating time from the start of the compressor, and the opening degree of the electric expansion valve opening degree is calculated until a predetermined time elapses. By maintaining
By collecting the refrigerating machine oil accumulated in the stopped indoor unit into the compressor, there is an effect that the refrigerating machine oil accumulated in the stopped indoor unit can be more reliably collected in the compressor.

Further, in the expansion valve control device for a multi-room air conditioner according to the present invention, when the predetermined time has elapsed by the required compressor operating time calculation means, the electric expansion valve opening of the stopped indoor unit is opened. By returning the degree to a predetermined degree, it is possible to reliably collect the refrigerating machine oil taken out when the compressor is started,
There is an effect that it is possible to prevent heat loss caused by making the electric expansion valve of the stopped indoor unit larger than a predetermined opening.

Further, the expansion valve control device for a multi-room air conditioner according to the present invention is provided with a stop indoor unit capacity determining means for determining the capacity of the stop indoor unit, and
When the electric expansion valve opening of the stopped indoor unit is determined, the optimal electric expansion valve opening of the stopped indoor unit where the refrigeration oil of the stopped indoor unit does not stay can be determined. Moreover, there is an effect that the refrigerating machine oil accumulated in the stopped indoor unit can be surely collected in the compressor.

In the expansion valve control method for a multi-room air conditioner according to the present invention, in the heating operation with the stopped indoor unit, the opening degree of the electric expansion valve for controlling the refrigerant flow rate of the stopped indoor unit from the start of the compressor. A step of setting a larger than a predetermined opening degree, a step of determining whether the amount of refrigerating machine oil taken out from the compressor is large based on the compressor shell temperature, and if it is determined that the amount of refrigerating machine oil taken out is large, A step of maintaining the opening degree of the electric expansion valve, and by collecting the refrigerating machine oil discharged from the compressor, by maintaining the opening degree when it is determined that the carry-out amount of the refrigerating machine oil is large. The refrigerating machine oil is prevented from accumulating in the stopped indoor unit, the refrigerating machine oil discharged from the compressor can be collected, and there is an effect of securing a sufficient refrigerating machine oil amount so as not to cause a failure of the compressor.

Further, in the expansion valve control method for a multi-room air conditioner according to the present invention, the amount of refrigerating machine oil taken out is large when the compressor shell temperature is low. By determining that the taken-out amount of refrigerating machine oil from the compressor is small when the compressor shell temperature is high, it is possible to judge the taken-out amount of refrigerating machine oil only by detecting the compressor shell temperature.

Further, the expansion valve control method for a multi-room air conditioner according to the present invention determines the refrigerating machine oil carry-out amount by
When the amount of refrigerating machine oil taken out from the compressor is small, that is, when the compressor shell temperature is higher than a predetermined value, by returning the electric expansion valve opening degree of the stopped indoor unit to the predetermined opening degree, it is taken out at the time of starting the compressor. The refrigerating machine oil can be reliably collected,
There is an effect that it is possible to prevent heat loss caused by making the electric expansion valve of the stopped indoor unit larger than a predetermined opening.

Further, according to the expansion valve control method for a multi-room air conditioner according to the present invention, the refrigerating machine oil is recovered even when it is judged that the taken-out amount of the refrigerating machine oil from the compressor is small on the basis of the compressor shell temperature. Judge whether the required time of has passed,
By maintaining the opening degree of the electric expansion valve opening degree until a predetermined time elapses, the refrigerating machine oil accumulated in the stopped indoor unit is recovered by the compressor, so that the refrigerating machine oil accumulated in the stopped indoor unit is more effectively collected. There is an effect that it can be reliably collected in the compressor.

In the expansion valve control method for a multi-room air conditioner according to the present invention, when the predetermined time for refrigerating machine oil recovery has elapsed, the electric expansion valve opening degree of the stopped indoor unit is changed to the predetermined opening degree. When the compressor is started, the refrigerating machine oil taken out can be surely recovered, and the heat dissipation loss caused by making the electric expansion valve of the stopped indoor unit larger than a predetermined opening degree can be prevented. .

In the expansion valve control method for a multi-room air conditioner according to the present invention, the capacity of the stopped indoor unit is determined and the electric expansion valve opening degree of the stopped indoor unit is determined based on the capacity of the stopped indoor unit. By this, the optimum electric expansion valve opening of the stopped indoor unit where the refrigeration oil of the stopped indoor unit does not stay can be determined, so even when an indoor unit of any volume is connected, the refrigeration oil accumulated in the stopped indoor unit It has the effect that it can be reliably collected in the compressor.

[Brief description of drawings]

FIG. 1 shows the first embodiment and is a system configuration diagram showing an expansion valve control device of a multi-room air conditioner.

FIG. 2 is a diagram showing the first embodiment, and is a relationship diagram between a compressor shell temperature and a refrigerator oil carry-out amount.

FIG. 3 is a diagram showing the first embodiment and is a control flowchart showing the operation content.

FIG. 4 is a diagram illustrating the second embodiment and is a system configuration diagram illustrating an expansion valve control device of a multi-room air conditioner.

FIG. 5 is a diagram showing the second embodiment, and is a relationship diagram between the electric expansion valve opening degree of the stopped indoor unit and the amount of refrigerating machine oil collected from the stopped indoor unit.

FIG. 6 is a diagram showing the second embodiment and is a control flowchart showing the operation contents.

FIG. 7 is a diagram showing the third embodiment and is a system configuration diagram showing an expansion valve control device of a multi-room air conditioner.

FIG. 8 is a diagram showing the third embodiment and is a relationship diagram of the volume of the stopped indoor unit and the opening degree of the electric expansion valve necessary to prevent accumulation in the stopped indoor unit.

FIG. 9 is a diagram showing the third embodiment and is a control flowchart showing the operation content.

FIG. 10 is a system configuration diagram showing an expansion valve control device of a conventional multi-room air conditioner.

[Explanation of symbols]

1 outdoor unit, 2 indoor unit A, 3 indoor unit B, 4 compressor, 5 four-way valve, 6 outdoor heat exchanger, 7 electric expansion valve for indoor unit A, 8 electric expansion valve for indoor unit B, 9 indoor unit A Heat exchanger, 10 Indoor unit B heat exchanger, 11 Outdoor heat exchanger temperature detecting means, 12 Refrigerant trapping judging means, 13
Electric expansion valve opening correction means, 14 compressor shell temperature detection means, 15 refrigerating machine oil take-out determination means, 16 required compressor operating time calculation means, 17 stopped indoor unit capacity determination means.

Claims (12)

[Claims] 1. A multi-room air conditioner having a plurality of indoor units and a single outdoor unit having a plurality of electric expansion valves for controlling the refrigerant flow rate of each indoor unit. During operation, means for setting the opening degree of the electric expansion valve for controlling the refrigerant flow rate of the stopped indoor unit to be larger than a predetermined opening degree from the time of starting the compressor, and refrigerating machine oil from the compressor based on the compressor shell temperature. The refrigerating machine oil take-out judging means for judging whether the take-out quantity of the refrigerating machine oil is large, and the electric expansion valve for maintaining the opening degree of the electric expansion valve when the refrigerating machine oil take-out judging means judges that the take-out quantity of the refrigerating machine oil is large. An expansion valve control device for a multi-chamber air conditioner, comprising: an opening correction means; and collecting refrigerating machine oil discharged from a compressor. 2. The amount of refrigerating machine oil taken out from the compressor is large when the compressor shell temperature is low, and the amount of refrigerating machine oil taken out of the compressor is high when the compressor shell temperature is high. The expansion valve control device for a multi-room air conditioner according to claim 1, wherein the expansion valve control device is determined to be small. 3. The refrigerating machine oil carry-out determination means,
The electric expansion valve opening degree of the stopped indoor unit is returned to a predetermined opening degree when the carry-out amount of the refrigerating machine oil from the compressor is small, that is, when the compressor shell temperature is higher than a predetermined value. An expansion valve control device for a multi-room air conditioner as described. 4. A necessary compressor operating time calculating means for determining whether a required time for refrigerating machine oil recovery has elapsed, and even when the refrigerating machine oil take-out judging means judges that the taken-out amount of refrigerating machine oil is small, The required compressor operating time calculating means calculates the operating time from the start of the compressor and maintains the opening of the electric expansion valve opening until a predetermined time elapses, thereby refrigerating machine oil accumulated in the stopped indoor unit. The expansion valve control device of the multi-room air conditioner according to claim 1, wherein the expansion valve control device recovers the air. 5. The electric expansion valve opening degree of the stopped indoor unit is returned to the predetermined opening degree by the required compressor operating time calculating means when the predetermined time period has elapsed. An expansion valve control device for a multi-room air conditioner as described. 6. The stopped indoor unit capacity determining means for determining the capacity of the stopped indoor unit is provided, and the electric expansion valve opening of the stopped indoor unit is determined by the capacity of the stopped indoor unit. The expansion valve control device for a multi-room air conditioner according to claim 4. 7. A multi-room air conditioner having a plurality of indoor units and a single outdoor unit equipped with a plurality of electric expansion valves for controlling the refrigerant flow rate of each indoor unit. In operation, from the start of the compressor, the step of setting the opening of the electric expansion valve that controls the refrigerant flow rate of the stopped indoor unit to be larger than a predetermined opening, and the operation of refrigerating machine oil from the compressor based on the compressor shell temperature. The process includes a step of determining whether the taken-out amount is large, and a step of maintaining the opening degree of the electric expansion valve when it is judged that the taken-out amount of the refrigerating machine oil is large, and collecting the refrigerating machine oil discharged from the compressor. An expansion valve control method for a multi-room air conditioner, comprising: 8. The determination of the refrigerating machine oil take-out amount is such that when the compressor shell temperature is low, the refrigerating machine oil take-out amount is large, and when the compressor shell temperature is high, the refrigerating machine oil take-out amount of the refrigerating machine oil is high. The expansion valve control method for a multi-room air conditioner according to claim 7, wherein it is determined that the carry-out amount is small. 9. The determination of the amount of refrigerating machine oil taken out,
The electric expansion valve opening degree of the stopped indoor unit is returned to a predetermined opening degree when the carry-out amount of the refrigerating machine oil from the compressor is small, that is, when the compressor shell temperature is higher than a predetermined value. An expansion valve control method for a multi-room air conditioner as described. 10. Even if it is determined based on the compressor shell temperature that the amount of refrigerating machine oil taken out from the compressor is small, it is determined whether the required time for refrigerating machine oil recovery has elapsed, and until the predetermined time elapses. The expansion valve for a multi-chamber air conditioner according to claim 7, wherein refrigerating machine oil accumulated in the stopped indoor unit is recovered in the compressor by maintaining the opening degree of the electric expansion valve opening degree. Control method. 11. The multi-chamber type air according to claim 10, wherein the opening degree of the electric expansion valve of the stopped indoor unit is returned to a predetermined opening degree when a predetermined time for refrigerating machine oil recovery has elapsed. Control method for expansion valve of air conditioner. 12. The multi-chamber according to claim 7 or 10, wherein the capacity of the stopped indoor unit is determined, and the electric expansion valve opening degree of the stopped indoor unit is determined based on the capacity of the stopped indoor unit. Type air conditioner expansion valve control method.