CN113483449B - Oil return control method for indoor unit - Google Patents
Oil return control method for indoor unit Download PDFInfo
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- CN113483449B CN113483449B CN202110778994.XA CN202110778994A CN113483449B CN 113483449 B CN113483449 B CN 113483449B CN 202110778994 A CN202110778994 A CN 202110778994A CN 113483449 B CN113483449 B CN 113483449B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/50—Control or safety arrangements characterised by user interfaces or communication
- F24F11/61—Control or safety arrangements characterised by user interfaces or communication using timers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
- F24F11/63—Electronic processing
- F24F11/64—Electronic processing using pre-stored data
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/62—Control or safety arrangements characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
- F24F11/63—Electronic processing
- F24F11/65—Electronic processing for selecting an operating mode
- F24F11/67—Switching between heating and cooling modes
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/70—Control systems characterised by their outputs; Constructional details thereof
- F24F11/80—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air
- F24F11/86—Control systems characterised by their outputs; Constructional details thereof for controlling the temperature of the supplied air by controlling compressors within refrigeration or heat pump circuits
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B41/00—Fluid-circulation arrangements
- F25B41/30—Expansion means; Dispositions thereof
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
- F25B43/02—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat for separating lubricants from the refrigerant
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F2140/00—Control inputs relating to system states
- F24F2140/20—Heat-exchange fluid temperature
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
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Abstract
The invention relates to the technical field of air conditioner oil return, in particular to an indoor unit oil return control method. The problem of how to guarantee indoor set oil return is aimed at to solve. For this purpose, the air conditioner of this application includes the recovery pipeline, and its one end and outdoor heat exchanger export intercommunication, the other end and compressor induction port intercommunication are equipped with the on-off valve on the recovery pipeline. The control method comprises the following steps: in the refrigeration mode, when the continuous operation time of the air conditioner reaches a first preset time length, calculating a first high-low pressure ratio of the pressure of the outdoor heat exchanger to the pressure of the indoor heat exchanger; when the continuous operation time of the air conditioner reaches a second preset time, calculating a second high-low pressure ratio of the pressure of the outdoor heat exchanger to the pressure of the indoor heat exchanger; judging the range of the first ratio of the second high-low pressure ratio and the first high-low pressure ratio; and selectively executing the oil return operation of the indoor unit according to the judgment result. This application can realize the effective oil return of indoor set, guarantees lubricated effect of compressor and air conditioner operation effect.
Description
Technical Field
The invention relates to the technical field of air conditioner oil return, in particular to an indoor unit oil return control method.
Background
The refrigerating machine oil inside the compressor has three functions: sealing the compression part, cooling the motor and lubricating the moving parts. In the refrigerant circulation process of the air conditioning system, the refrigerating machine oil can participate in circulation along with the refrigerant.
Under the refrigeration condition, when the refrigerating machine oil circulates to the indoor heat exchanger along with the refrigerant, the flowing of the refrigerating machine oil is influenced because the hairpin pipe of the existing heat exchanger is the internal thread copper pipe, and in addition, the centrifugal force action of the flowing of the refrigerant causes that part of the refrigerating machine oil cannot return to the inside of the compressor in time and stays on the inner wall of the thread copper pipe, so that the heat transfer between the refrigerant and the coil pipe is blocked, the heat transfer temperature difference is reduced, and the refrigerating and heating effects of the air conditioner are poor. Meanwhile, as part of the refrigerating machine oil does not return to the interior of the compressor in time, the problems of insufficient lubrication of the compressor and the like can also occur. Therefore, how to control oil return of the indoor heat exchanger becomes an urgent problem to be solved by air conditioner manufacturers.
Accordingly, there is a need in the art for a new oil return control method for an indoor unit to solve the above problems.
Disclosure of Invention
In order to solve at least one problem in the prior art, namely to solve the problem of how to ensure oil return of the indoor unit, the application provides an oil return control method of the indoor unit, which is applied to an air conditioner, wherein the air conditioner comprises a compressor, a four-way valve, an outdoor heat exchanger, a throttling device and an indoor heat exchanger which are connected through refrigerant pipelines, a first pressure sensor is arranged on the indoor heat exchanger, a second pressure sensor is arranged on the outdoor heat exchanger, the air conditioner also comprises a recovery pipeline, one end of the recovery pipeline is communicated with an outlet of the outdoor heat exchanger, the other end of the recovery pipeline is communicated with an air suction port of the compressor, an on-off valve is arranged on the recovery pipeline, and the on-off valve is a normally-closed valve,
the control method comprises the following steps:
in a refrigeration mode, when the continuous operation time of the air conditioner reaches a first preset time length, calculating a first high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger;
when the continuous operation time of the air conditioner reaches a second preset time, calculating a second high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger;
judging the range of a first ratio between the second high-low pressure ratio and the first high-low pressure ratio;
selectively executing oil return operation of the indoor unit according to the judgment result;
and the second preset time length is greater than the first preset time length.
In a preferred embodiment of the oil return control method for the indoor unit, the step of "selectively performing an oil return operation of the indoor unit according to the determination result" further includes:
and if the first ratio is larger than or equal to a first threshold value, executing oil return operation of the indoor unit.
In a preferred technical solution of the above indoor unit oil return control method, the step of "selectively performing an indoor unit oil return operation according to a judgment result" further includes:
if the first ratio is smaller than the first threshold value and larger than or equal to a second threshold value, acquiring a first operating frequency of the compressor;
judging the magnitude of the first operating frequency and the first oil return frequency;
if the first operation frequency is less than the first oil return frequency, controlling the compressor to be in an up-conversion operation to the first oil return frequency;
when the compressor continuously operates at the first oil return frequency for a third preset time length, calculating a third high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger;
judging the range of a second ratio between the third high-low pressure ratio and the second high-low pressure ratio;
and selectively executing the oil return operation of the indoor unit according to the judgment result.
In a preferred embodiment of the indoor unit oil return control method, the step of "selectively performing the indoor unit oil return operation according to the determination result" further includes:
if the second ratio is smaller than the first threshold and larger than or equal to the second threshold, controlling the compressor to increase the frequency to a second oil return frequency for operation;
calculating a fourth high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger when the compressor continuously operates at the second oil return frequency for a fourth preset time length;
judging the range of a third ratio between the fourth high-low pressure ratio and the third high-low pressure ratio;
selectively executing oil return operation of the indoor unit according to the judgment result; and/or
And if the second ratio is smaller than the second threshold value, controlling the air conditioner to keep the current running state, and executing the oil return operation of the indoor unit until the ratio between the high-low pressure ratio and the high-low pressure ratio calculated twice is larger than or equal to the first threshold value.
In a preferred embodiment of the indoor unit oil return control method, the step of "selectively performing the indoor unit oil return operation according to the determination result" further includes:
if the third ratio is smaller than the first threshold and larger than or equal to the second threshold, executing oil return operation of the indoor unit; and/or
And if the third ratio is smaller than the second threshold, controlling the air conditioner to keep the current running state, and executing the oil return operation of the indoor unit until the ratio between the high-low pressure ratio and the high-low pressure ratio calculated twice is larger than or equal to the first threshold.
In a preferred technical solution of the indoor unit oil return control method, the control method further includes:
if the first operating frequency is greater than or equal to the first oil return frequency, further judging the magnitude of the first operating frequency and the second oil return frequency;
if the first operation frequency is smaller than the second oil return frequency, controlling the compressor to increase the frequency to the second oil return frequency for operation;
calculating a fifth high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger when the compressor continuously operates at the second oil return frequency for a fifth preset time duration;
judging the range of a fourth ratio between the fifth high-low pressure ratio and the second high-low pressure ratio;
selectively executing oil return operation of the indoor unit according to the judgment result; and/or
And if the first operating frequency is greater than or equal to the second oil return frequency, controlling the air conditioner to keep the current operating state until the ratio of the high-pressure ratio to the low-pressure ratio calculated twice is greater than or equal to the first threshold value, and then executing oil return operation of the indoor unit.
In a preferred embodiment of the indoor unit oil return control method, the step of "selectively performing the indoor unit oil return operation according to the determination result" further includes:
if the fourth ratio is smaller than the first threshold and larger than or equal to the second threshold, executing oil return operation of the indoor unit; and/or
And if the fourth ratio is smaller than the second threshold, controlling the air conditioner to keep the current running state, and executing the oil return operation of the indoor unit until the ratio between the high-low pressure ratio and the high-low pressure ratio calculated twice is larger than or equal to the first threshold.
In a preferred embodiment of the oil return control method for the indoor unit, the step of "selectively performing an oil return operation of the indoor unit according to the determination result" further includes:
and if the first ratio is smaller than a second threshold value, the oil return operation of the indoor unit is not executed, and the air conditioner is controlled to keep the current running state.
In a preferred technical solution of the above indoor unit oil return control method, "executing an indoor unit oil return operation" further includes:
controlling the compressor to reduce the frequency to a first reversing frequency;
controlling the four-way valve to change direction to convert into a heating mode;
after the four-way valve is switched, controlling the indoor fan to continuously run for a sixth preset time and then closing the indoor fan;
controlling the compressor to increase the frequency to a third oil return frequency;
and controlling the on-off valve to be opened, and opening the throttling device to the maximum opening degree.
In a preferred embodiment of the oil return control method for an indoor unit, after the step of "controlling the on-off valve to be opened and the throttle device to be opened to the maximum opening", the control method further includes:
after the on-off valve is opened and lasts for a seventh preset time, controlling the compressor to reduce the frequency to a second reversing frequency;
controlling the four-way valve to change direction to convert into a refrigeration mode;
controlling the indoor fan to start and operate;
determining a second operating frequency based on the set temperature, and controlling the compressor to operate according to the second operating frequency;
and controlling the on-off valve to be closed.
It should be noted that, in the preferred technical scheme of this application, the air conditioner includes the compressor through refrigerant tube coupling, the cross valve, outdoor heat exchanger, throttling arrangement, indoor heat exchanger, be provided with first pressure sensor on the indoor heat exchanger, be provided with second pressure sensor on the outdoor heat exchanger, the air conditioner still includes the recovery pipeline, the one end of recovery pipeline and the export intercommunication of outdoor heat exchanger, the other end of recovery pipeline and the induction port intercommunication of compressor, be provided with the on-off valve on the recovery pipeline, the on-off valve is the normally closed valve, the control method includes: in the refrigeration mode, when the continuous operation duration of the air conditioner reaches a first preset duration, calculating a first high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger; when the continuous operation time of the air conditioner reaches a second preset time, calculating a second high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger; judging the range of the first ratio between the second high-low pressure ratio and the first high-low pressure ratio; selectively executing oil return operation of the indoor unit according to the judgment result; and the second preset time length is greater than the first preset time length.
Through the control mode, effective oil return of the indoor unit can be realized, and the lubricating effect of the compressor and the operation effect of the air conditioner are guaranteed. Specifically, a first high-low pressure ratio when the continuous operation time of the air conditioner reaches a first preset time and a second high-low pressure ratio when the continuous operation time of the air conditioner reaches a second preset time are calculated in a refrigeration mode, the range of a first ratio between the second high-low pressure ratio and the first high-low pressure ratio is judged, and then oil return operation of the indoor unit is selectively executed based on the judgment result.
Drawings
The oil return control method of the indoor unit of the present application is described below with reference to the accompanying drawings. In the drawings:
FIG. 1 is a system diagram of an air conditioner of the present application in a cooling mode;
FIG. 2 is a system diagram of the air conditioner of the present application in a heating mode;
fig. 3 is a flowchart of an oil return control method of an indoor unit according to the present application;
fig. 4 is a logic diagram of a possible implementation process of the oil return control method for the indoor unit according to the present application.
List of reference numerals
1. A compressor; 2. a four-way valve; 3. an outdoor heat exchanger; 4. a throttling device; 5. an indoor heat exchanger; 6. a refrigerant pipeline; 7. a recovery pipeline; 8. an on-off valve; 9. a reservoir; 10. a first pressure sensor; 11. a second pressure sensor.
Detailed Description
Preferred embodiments of the present application are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principles of the present application, and are not intended to limit the scope of the present application. For example, although the following detailed description describes the detailed steps of the method of the present application, those skilled in the art can combine, split and exchange the order of the above steps without departing from the basic principle of the present application, and the modified technical solution does not change the basic concept of the present application and therefore falls into the protection scope of the present application.
It should be noted that, in the description of the present application, the terms "first", "second", "third", "fourth", "fifth", "sixth", "seventh" and eighth "are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
It should also be noted that, unless expressly stated or limited otherwise, the term "coupled" is used in the description of the invention in its broadest sense, and thus, for example, may be fixedly coupled, releasably coupled, or integrally coupled; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those skilled in the art as the case may be.
First, referring to fig. 1, the structure of the air conditioner of the present application will be described. Fig. 1 is a system diagram of an air conditioner according to the present invention in a cooling mode.
As shown in fig. 1, in one possible embodiment, the air conditioner includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a throttling device 4, an indoor heat exchanger 5, and an accumulator 9. Compressor 1 'S gas vent passes through refrigerant pipeline 6 and the P interface intercommunication of cross valve 2, the C interface of cross valve 2 passes through refrigerant pipeline 6 and outdoor heat exchanger 3' S import intercommunication, refrigerant pipeline 6 and throttling arrangement 4 'S a port intercommunication is passed through in outdoor heat exchanger 3' S export, refrigerant pipeline 6 and indoor heat exchanger 5 'S import intercommunication is passed through to throttling arrangement 4' S another port, refrigerant pipeline 6 and cross valve 2 'S E interface intercommunication is passed through in indoor heat exchanger 5' S export, refrigerant pipeline 6 and reservoir 9 'S import intercommunication is passed through to cross valve 2' S S interface, the pipeline is passed through in reservoir 9 'S export and compressor 1' S induction port intercommunication. The throttling device 4 is preferably an electronic expansion valve, a filter screen is arranged in the liquid storage device 9, and the liquid storage device 9 can play roles in storing refrigerants, separating refrigerant gas and liquid, filtering oil stains, silencing, buffering the refrigerants and the like.
The air conditioner further comprises a recovery pipeline 7 and an on-off valve 8, wherein the recovery pipeline 7 is a copper pipe with a smooth inner wall, the first end of the copper pipe is arranged on a refrigerant pipeline 6 between the outlet of the outdoor heat exchanger 3 and the throttling device 4, and the second end of the copper pipe is arranged on the refrigerant pipeline 6 between an S interface of the four-way valve 2 and the inlet of the liquid storage device 9. The on-off valve 8 is preferably a solenoid valve which is a normally closed valve and is arranged on the recovery pipeline 7, and the solenoid valve is in communication connection with a controller of the air conditioner to receive an opening and closing signal sent by the controller. Of course, the on-off valve 8 may be an electrically controlled valve such as an electronic expansion valve.
In order to implement the following method, a first pressure sensor 10 is further disposed on the coil of the indoor heat exchanger 5, and the first pressure sensor 10 is used for detecting the pressure of the indoor heat exchanger 5. A second pressure sensor 11 is further arranged on the coil of the outdoor heat exchanger 3, and the second pressure sensor 11 is used for detecting the pressure of the outdoor heat exchanger 3. The principle of detecting the pressure of the heat exchanger by means of a pressure sensor is well known in the art and will not be described in detail herein.
The oil return control method of the indoor unit in the following embodiment will be described in conjunction with the structure of the air conditioner, but it can be understood by those skilled in the art that the specific structural composition of the air conditioner is not constant, and those skilled in the art can adjust the oil return control method, for example, the liquid reservoir 9 may be omitted, or other components may be added on the basis of the structure of the air conditioner.
The oil return control method of the indoor unit of the present application is described below with reference to fig. 1, fig. 2, and fig. 3. Wherein, fig. 2 is a system diagram of the air conditioner of the present application in a heating mode; fig. 3 is a flowchart of an indoor unit oil return control method according to the present application.
As shown in fig. 1, when the air conditioner operates in the cooling mode, the flow direction of the refrigerant is as follows: compressor → four-way valve → outdoor heat exchanger → throttling device → indoor heat exchanger → four-way valve → compressor. The refrigerant is in high temperature and high pressure state in the outdoor heat exchanger and in low temperature and low pressure state in the indoor heat exchanger, so that the refrigerating machine oil is easier to accumulate in the indoor heat exchanger.
As shown in fig. 3, in order to solve the problem of how to ensure oil return of the indoor unit, the oil return control method of the indoor unit of the present application includes:
s101, in a refrigeration mode, when the continuous operation time of the air conditioner reaches a first preset time, calculating a first high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger.
In a possible embodiment, the first preset time period may be any value from 10min to 50min, preferably 30min in the present application, and when the air conditioner continuously operates in the cooling mode for 30min, the pressure of the indoor heat exchanger and the pressure of the outdoor heat exchanger are respectively detected by the first pressure sensor and the second pressure sensor, and then a first high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger is calculated.
And S103, when the continuous operation time of the air conditioner reaches a second preset time, calculating a second high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger.
In a possible embodiment, the second preset time period is longer than the first preset time period, the second preset time period may be any value from 30min to 90min, preferably 60min in the present application, after the air conditioner operates in the cooling mode for 30min, and then continues to operate for 30min, that is, when the continuous operation time period reaches 60min, the pressure of the indoor heat exchanger and the pressure of the outdoor heat exchanger are detected by the first pressure sensor and the second pressure sensor, respectively, and then the second high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger is calculated.
And S105, judging the range of the first ratio between the second high-low pressure ratio and the first high-low pressure ratio.
In one possible embodiment, after obtaining the first high-low pressure ratio and the second high-low pressure ratio, a first ratio between the second high-low pressure ratio and the first high-low pressure ratio is calculated, and a range in which the first ratio is located is determined. In the application, the first ratio is compared with the first threshold and the second threshold, and the range where the first ratio is located is judged. Wherein the first threshold is greater than the second threshold. In the present application, the first threshold value may be any value from 1.3 to 1.6, and the second threshold value may be any value from 1.05 to 1.3.
And S107, selectively executing the oil return operation of the indoor unit according to the judgment result.
In one possible embodiment, the step of selectively performing an oil return operation of the indoor unit according to the determination result specifically includes:
(1) and if the first ratio is greater than or equal to the first threshold value, executing oil return operation of the indoor unit. When the first ratio is greater than or equal to the first threshold, it is proved that the high-low pressure ratio of the air conditioner is increased in a large range during continuous cooling operation, that is, more refrigerating machine oil is accumulated in the indoor heat exchanger, resulting in an increase in the high-low pressure of the air conditioner. At this time, it is necessary to immediately perform an oil return operation of the indoor unit so that the refrigerating machine oil accumulated in the indoor unit is returned to the compressor.
(2) And if the first ratio is smaller than the second threshold value, the oil return operation of the indoor unit is not executed, and the air conditioner is controlled to keep the current running state. When the first ratio is smaller than the second threshold, it is proved that the high-low pressure ratio of the air conditioner is not changed greatly during continuous refrigerating operation, the air conditioner operates more stably, and the oil return is normal. At the moment, the oil return operation of the indoor unit is not required to be executed, and the air conditioner is controlled to keep the current running state.
(3) If the first ratio is smaller than a first threshold value and larger than or equal to a second threshold value, acquiring a first operating frequency of the compressor; and judging the magnitude of the first operating frequency and the first oil return frequency. When the first ratio is smaller than the first threshold and greater than or equal to the second threshold, it is proved that the high-low pressure ratio of the air conditioner is increased to a certain extent during continuous cooling operation, and the refrigerating machine oil in the indoor heat exchanger is accumulated to a certain extent. However, since the oil return operation of the indoor unit described below temporarily switches the operation mode of the air conditioner, terminates the adjustment of the indoor air, and has a large influence on the user experience, when the first ratio is smaller than the first threshold and is greater than or equal to the second threshold, the first operation frequency of the compressor is obtained first, and how to operate is determined based on the first operation frequency, the first oil return frequency, and the second oil return frequency. Specifically, the method comprises the following steps:
(3a) and if the first operation frequency is less than the first oil return frequency, controlling the compressor to be operated up to the first oil return frequency. In the prior art, in order to ensure that the refrigerating machine oil smoothly flows back to the compressor, an oil return frequency is generally set, and when the air conditioner operates at the oil return frequency, the refrigerating machine oil can well flow back to the compressor. This application utilizes this technical means, when first operating frequency is less than first oil return frequency, controls the compressor earlier and rises frequently to first oil return frequency operation to under the prerequisite that does not change the operational mode of air conditioner, make refrigerator oil can flow back to the compressor smoothly.
Further, when the compressor continuously operates at the first oil return frequency for a third preset time length, calculating a third high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger; judging the range of a second ratio between the third high-low pressure ratio and the second high-low pressure ratio; if the second ratio is smaller than the first threshold and larger than or equal to the second threshold, controlling the compressor to increase the frequency to a second oil return frequency for operation; and if the second ratio is smaller than the second threshold value, controlling the air conditioner to keep the current running state until the ratio between the high-low pressure ratio and the high-low pressure ratio calculated twice in sequence is larger than or equal to the first threshold value, and executing oil return operation of the indoor unit.
Specifically, the third preset duration may be any value from 5min to 20min, 10min is taken in the present application, when the compressor continuously operates at the first oil return frequency for 10min, a better oil return effect has been theoretically achieved, at this time, the third high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger is calculated again, and the range where the second ratio between the third high-low pressure ratio and the second high-low pressure is located is determined to verify the oil return effect. If the second ratio is still between the first threshold and the second threshold, the current oil return effect is proved to be poor, the high-low pressure ratio of the air conditioner is still increased, at the moment, the compressor is controlled to continuously increase the frequency to the second oil return frequency for operation, and the air conditioner is subjected to oil return at a higher oil return frequency. When the second ratio is smaller than the second threshold value, the fact that the high-low pressure ratio of the air conditioner falls back is proved, a certain oil return effect is achieved, the comfort level of the indoor environment is preferentially guaranteed at the moment, the air conditioner is controlled to keep the current running state to continue running, and the oil return operation of the indoor unit is executed until the ratio between the high-low pressure ratio calculated twice is larger than or equal to the first threshold value. The interval between the two successive calculations of the high-low pressure ratio can be set arbitrarily, such as 10min or 20 min.
For example, when the second ratio is smaller than the second threshold, the air conditioner is controlled to continue to operate by taking the current set temperature as the target temperature, and the frequency of the compressor, the opening degree of the throttling device, the wind speed of the indoor fan and the wind speed of the outdoor fan and the like can be adjusted in the operation process. And in the process of continuing operation, acquiring the high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger every 10 min. After at least two high-low pressure ratios are continuously obtained, the ratio between the two high-low pressure ratios is calculated, the ratio is compared with a first threshold value, and when the ratio is larger than or equal to the first threshold value, oil return operation is directly executed.
Further, when the compressor continuously operates for a fourth preset time length at the second oil return frequency, a fourth high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger is calculated; judging the range of a third ratio between the fourth high-low pressure ratio and the third high-low pressure ratio; if the third ratio is smaller than the first threshold and larger than or equal to the second threshold, executing oil return operation of the indoor unit; and if the third ratio is smaller than the second threshold, controlling the air conditioner to keep the current running state until the ratio between the high-low pressure ratio and the high-low pressure ratio calculated twice in sequence is larger than or equal to the first threshold, and executing oil return operation of the indoor unit.
Specifically, the fourth preset duration may be any value from 5min to 20min, 10min is taken in the present application, when the compressor continuously operates at the second oil return frequency for 10min, a better oil return effect has been theoretically achieved, at this time, the fourth high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger is calculated again, and the range where the third ratio between the fourth high-low pressure ratio and the third high-low pressure is located is determined to verify the oil return effect. If the third ratio is still between the first threshold and the second threshold, the current oil return effect is poor, the high-low pressure ratio of the air conditioner is still increased, and at the moment, the compressor is controlled to directly execute oil return operation of the indoor unit so as to perform forced oil return on the indoor unit. When the third ratio is smaller than the second threshold, the fact that the high-low pressure ratio of the air conditioner falls back is proved, a certain oil return effect is achieved, the comfort level of the indoor environment is preferentially guaranteed at the moment, the air conditioner is controlled to keep the current running state to continue running, and the oil return operation of the indoor unit is executed until the ratio between the high-low pressure ratio calculated twice is larger than or equal to the first threshold. The step of controlling the air conditioner to keep running continuously in the current running state until the ratio between the high-low pressure ratio calculated twice is greater than or equal to the first threshold value and then performing the oil return operation of the indoor unit is similar to the control process, and is not described again here.
(3b) And if the first operation frequency is greater than or equal to the first oil return frequency but less than the second oil return frequency, controlling the compressor to be operated at the second oil return frequency in an up-conversion mode. When the first operating frequency is greater than the first oil return frequency but less than the second oil return frequency, the compressor is controlled to be increased to the second oil return frequency for operation, so that the refrigerating machine oil can smoothly flow back to the compressor on the premise of not changing the operating mode of the air conditioner.
Further, when the compressor continuously operates at the second oil return frequency for a fifth preset time length, calculating a fifth high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger; judging the range of a fourth ratio between the fifth high-low pressure ratio and the second high-low pressure ratio; if the fourth ratio is smaller than the first threshold and larger than or equal to the second threshold, executing oil return operation of the indoor unit; and if the fourth ratio is smaller than the second threshold value, controlling the air conditioner to keep the current running state until the ratio between the high-low pressure ratio and the high-low pressure ratio calculated twice in sequence is larger than or equal to the first threshold value, and executing oil return operation of the indoor unit.
Similarly to the foregoing, the fifth preset duration may be any value from 5min to 20min, 10min is taken in this application, when the compressor continues to operate at the second oil return frequency for 10min, a better oil return effect has been theoretically achieved, at this time, the fifth high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger is calculated again, and the range where the fourth ratio between the fifth high-low pressure ratio and the second high-low pressure is located is determined to verify the oil return effect. If the fourth ratio is still between the first threshold and the second threshold, the current oil return effect is poor, the high-low pressure ratio of the air conditioner is still increased, and at the moment, the compressor is controlled to directly execute oil return operation of the indoor unit so as to perform forced oil return on the indoor unit. When the fourth ratio is smaller than the second threshold value, the fact that the high-low pressure ratio of the air conditioner falls back is proved, a certain oil return effect is achieved, the comfort level of the indoor environment is preferentially guaranteed at the moment, the air conditioner is controlled to keep the current running state to continue running, and the oil return operation of the indoor unit is executed until the ratio between the high-low pressure ratio calculated twice is larger than or equal to the first threshold value. The step of controlling the air conditioner to keep running continuously in the current running state until the ratio between the high-low pressure ratio calculated twice is greater than or equal to the first threshold value and then performing the oil return operation of the indoor unit is similar to the control process, and is not described again here.
(3c) And if the first operation frequency is greater than or equal to the second oil return frequency, controlling the air conditioner to keep the current operation state, and executing the oil return operation of the indoor unit until the ratio of the high-low pressure ratio calculated twice is greater than or equal to the first threshold value. If the first operation frequency is greater than or equal to the second oil return frequency, the current compressor is proved to be in high-frequency operation, oil return cannot be achieved in a frequency increasing mode, at the moment, the air conditioner is controlled to keep the current operation state, and the oil return operation of the indoor unit is executed until the ratio between the high-pressure ratio and the low-pressure ratio calculated twice is greater than or equal to the first threshold value. The step of controlling the air conditioner to keep running continuously in the current running state until the ratio between the high-low pressure ratio calculated twice is greater than or equal to the first threshold value and then executing the oil return operation of the indoor unit is similar to the control process, and is not described herein again.
In one possible embodiment, the step of "performing an indoor unit oil return operation" further includes:
controlling the compressor to reduce the frequency to a first reversing frequency; controlling the four-way valve to change the direction to convert into a heating mode; after the four-way valve is switched, controlling the indoor fan to continuously run for a sixth preset time and then closing the indoor fan; controlling the compressor to increase the frequency to a third oil return frequency; and controlling the on-off valve to be opened, and opening the throttling device to the maximum opening degree.
Specifically, the normal operating frequency of the compressor is high, and the four-way valve cannot be reversed. Therefore, when the air conditioner starts to perform the oil return operation of the indoor unit, the compressor is first lowered from the normal operating frequency to a first reversing frequency that can allow the four-way valve to reverse, so that the four-way valve can reverse to switch to the heating mode.
After the four-way valve is switched, the air conditioner runs in a heating mode, and if the indoor unit continues to supply air, hot air is blown to the indoor space, so that poor use experience is brought to users. At this moment, the control room fan operation sixth is preset for a long time, blows off the residual cold, then the shutdown avoids the air-out becoming hot, influences user experience. The sixth preset time period may be any value from 10s to 1min, and may be 30s in the present application.
After the four-way valve is switched, the compressor is controlled to be frequency-raised to a third oil return frequency, and the third oil return frequency can be the highest frequency of the compressor in the application. At this frequency, the compressor can increase the temperature and pressure of the refrigerant in the shortest time, thereby improving the oil return effect.
And when the operation mode is switched to the heating mode, the on-off valve is controlled to be opened, and the throttling device is opened to the maximum opening degree. At this time, as shown by arrows in fig. 2, the high-temperature and high-pressure refrigerant discharged from the compressor flows through the indoor heat exchanger, the high-temperature and high-pressure refrigerant quickly impacts the coil of the indoor heat exchanger, and the refrigerating machine oil inside the coil flows back to the reservoir through the recovery pipeline under the driving of the high-temperature refrigerant, so that the machine oil is recovered. The throttle device is controlled to be opened to the maximum opening degree, so that high-temperature and high-pressure refrigerants can rapidly pass through the throttle device, the pressure drop in the flowing process of the refrigerants is reduced, and the oil return effect of the indoor unit is improved.
In one possible embodiment, after the step of "controlling the on-off valve to be opened and the throttle device to be opened to the maximum opening degree", the control method further includes: after the on-off valve is opened and lasts for a seventh preset time, controlling the compressor to reduce the frequency to a second reversing frequency; controlling the four-way valve to change direction to convert into a refrigeration mode; controlling the indoor fan to start and operate; determining a second operating frequency based on the set temperature, and controlling the compressor to operate according to the second operating frequency; and controlling the on-off valve to be closed.
Wherein, the seventh preset time period can be any value from 5min to 15min, and the application is preferably 10 min. When the opening time of the throttling device and the on-off valve lasts for 10min, the high-temperature and high-pressure refrigerant is circulated for many times to generate a better oil return effect, so that the oil return operation of the indoor unit can be quitted when the throttling device and the on-off valve are opened for 10 min.
Specifically, after the oil return operation of the indoor unit is completed, the air conditioner needs to be restored to the operation mode before entering the oil return operation to continue to adjust the indoor temperature. At this time, the compressor is controlled to be reduced from the current working frequency to a second reversing frequency which can allow the four-way valve to reverse, so that the four-way valve can reverse, the refrigeration mode is switched to, the indoor fan is controlled to start to operate, the second operating frequency of the compressor is determined based on the set temperature, then the compressor is controlled to operate at the second operating frequency, and the on-off valve is controlled to be closed. Thus, the refrigerant flows in the direction of the normal cooling mode. By this point, the oil return operation is ended.
Of course, the mode of exiting the indoor unit oil-return operation is not limited to the above-mentioned one, and a person skilled in the art can freely select a specific control mode on the premise of being able to restore the air conditioner to the operation state before entering the indoor unit oil-return operation, and such a selection does not deviate from the principle of the present application. For example, the air guide plate of the indoor unit can supply air upwards when the indoor fan is started, so that the problem that poor use experience is brought to users due to the fact that the temperature of the coil pipe of the indoor heat exchanger is too high and the air is discharged when the air conditioner is just switched to the cooling mode is avoided. For another example, the throttle device may be controlled to maintain the maximum opening, and since refrigerant circulates between the compressor and the indoor heat exchanger when the oil return operation of the indoor unit is performed, refrigerant in the outdoor heat exchanger is lost, the throttle device maintains the maximum opening, so that the refrigerant quickly fills the outdoor heat exchanger, and normal circulation of the refrigerant is realized as soon as possible.
The method comprises the steps of calculating a first high-low pressure ratio when the continuous operation time of the air conditioner reaches a first preset time and a second high-low pressure ratio when the continuous operation time of the air conditioner reaches a second preset time under a refrigeration mode, judging the range of a first ratio between the second high-low pressure ratio and the first high-low pressure ratio, and selectively executing oil return operation of the indoor unit based on the judgment result. During oil return operation, the air conditioner heat exchanger is controlled to be switched into a heating mode, the on-off valve and the throttling device are opened, the interior of a coil pipe of the indoor heat exchanger can be impacted by utilizing rapid flowing of high-temperature and high-pressure refrigerants, the refrigerating machine oil is directly returned to the interior of the liquid storage device along with the refrigerants through the recovery pipeline, and efficient oil return is achieved.
In addition, through set up the recovery pipeline in the air conditioner, this application can utilize the recovery pipeline to realize the recovery to refrigerator oil in carrying out indoor set oil return operation process, realizes that the high temperature high pressure refrigerant is scouring away the back to indoor heat exchanger, need not to pass through outdoor heat exchanger once more, but directly takes refrigerator oil back to the reservoir and retrieves, has reduced the flow stroke of high temperature refrigerant, has reduced along journey pressure drop, improves indoor set oil return effect.
It should be noted that the above control method is only a preferred embodiment of the present application, and those skilled in the art can adjust the above control method without departing from the principle of the present application.
For example, in an alternative embodiment, although the above example is described in connection with the comparison of the first ratio to the first threshold and the second threshold, it will be apparent to those skilled in the art that the threshold number may be adjusted without departing from the principles of the present application. For example, the first ratio is compared with only one threshold, or with three or four thresholds, etc.
For another example, in an alternative embodiment, the specific operation of the above embodiment when the first ratio is smaller than the first threshold and is greater than or equal to the second threshold is not constant, and a person skilled in the art may make adjustments based on the above control method, where the adjustments include, but are not limited to, adjusting the number of oil return frequencies, adjusting the preset time length, adjusting the step deletion of a partial intermediate process, and the like.
One possible implementation of the present application is described below with reference to fig. 4. Fig. 4 is a logic diagram of a possible implementation process of the oil return control method for the indoor unit according to the present application.
In one possible implementation, as shown in fig. 4, after the air conditioner operates in the cooling mode, the following operations are performed:
step S201 is performed first, and when the cooling continues to operate for 30min, the pressure P21 of the outdoor heat exchanger and the pressure P11 of the indoor heat exchanger are acquired, respectively, and K1 is calculated to be P21/P11.
Step S203 is performed next, and when the cooling continues to operate for 60min, the pressure P22 of the outdoor heat exchanger and the pressure P12 of the indoor heat exchanger are respectively obtained, and K2 is calculated to be P22/P12.
Next, step S205 is executed, calculating K2/K1 and determining whether K2/K1 ≧ 1.5 holds. If the determination result is positive, step S231 is executed, otherwise, if the determination result is negative, step S207 is executed.
S207, further judge whether K2/K1 < 1.1. When the judgment result is true, executing step S209; otherwise, when the determination result is false, step S211 is executed.
And S209, controlling the air conditioner to keep the current running state.
S211, acquiring the operation frequency f of the compressor and judging whether the operation frequency f < f1 is satisfied. If the determination result is true, go to step S213; otherwise, when the determination result is false, step S221 is executed.
And S213, controlling the compressor to be boosted to a first oil return frequency f1 and run for 10min, then respectively acquiring the pressure P23 of the outdoor heat exchanger and the pressure P13 of the indoor heat exchanger, and calculating K3 to be P23/P13.
Then, step S215 is executed, K3/K2 is calculated and it is judged whether 1.1. ltoreq.K 3/K2 < 1.5 holds. When the determination result is true, step S217 is performed, otherwise, when the determination result is false, step S227 is performed.
And S217, controlling the compressor to be frequency-increased to a second oil return frequency f2 and run for 10min, then respectively acquiring the pressure P24 of the outdoor heat exchanger and the pressure P14 of the indoor heat exchanger, and calculating K4 to be P24/P14.
Then, step S219 is performed, K4/K3 is calculated and it is judged whether 1.1. ltoreq.K 4/K3 < 1.5 holds. When the determination result is true, step S231 is executed, otherwise, when the determination result is false, step S227 is executed.
S221 determines whether or not the operating frequency f < f2 is satisfied. When the judgment result is true, executing step S223; otherwise, when the determination result is false, step S227 is executed.
And S223, controlling the compressor to be frequency-increased to a second oil return frequency f2 and running for 10min, then respectively acquiring the pressure P25 of the outdoor heat exchanger and the pressure P15 of the indoor heat exchanger, and calculating K5 to be P25/P15.
Then, step S225 is executed, K5/K2 is calculated and it is judged whether 1.1. ltoreq.K 5/K2 < 1.5 holds. When the determination result is true, step S231 is executed, otherwise, when the determination result is false, step S227 is executed.
And S227, keeping the current operation state, respectively acquiring the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger every 10min, and calculating the high-low pressure ratio of the outdoor heat exchanger and the indoor heat exchanger.
S229, calculating the ratio Kn +1/Kn between two adjacent high-low pressure ratios and judging whether the Kn +1/Kn is larger than or equal to 1.5. If the determination result is positive, step S231 is executed, otherwise, if the determination result is negative, the process returns to continue to execute step S227.
And S231, controlling the air conditioner to execute an indoor unit oil return operation.
Those skilled in the art will appreciate that the above described air conditioner may also include other well known structures such as processors, controllers, memories, etc., wherein the memories include, but are not limited to, ram, flash, rom, prom, volatile, non-volatile, serial, parallel, or registers, etc., and the processors include, but are not limited to, CPLD/FPGA, DSP, ARM processor, MIPS processor, etc. Such well-known structures are not shown in the drawings in order to not unnecessarily obscure embodiments of the present disclosure.
Although the foregoing embodiments describe the steps in the above sequential order, those skilled in the art can understand that, in order to achieve the effect of the present embodiments, the different steps need not be executed in such an order, and may be executed simultaneously (in parallel) or in an inverted order, and these simple changes are all within the scope of protection of the present application.
So far, the technical solutions of the present application have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present application is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the present application, and the technical scheme after the changes or substitutions will fall into the protection scope of the present application.
Claims (8)
1. An indoor unit oil return control method is applied to an air conditioner and is characterized in that the air conditioner comprises a compressor, a four-way valve, an outdoor heat exchanger, a throttling device and an indoor heat exchanger which are connected through refrigerant pipelines, a first pressure sensor is arranged on the indoor heat exchanger, a second pressure sensor is arranged on the outdoor heat exchanger, the air conditioner further comprises a recovery pipeline, one end of the recovery pipeline is communicated with an outlet of the outdoor heat exchanger, the other end of the recovery pipeline is communicated with an air suction port of the compressor, an on-off valve is arranged on the recovery pipeline and is a normally-closed valve,
the control method comprises the following steps:
in a refrigeration mode, when the continuous operation duration of the air conditioner reaches a first preset duration, calculating a first high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger;
when the continuous operation time of the air conditioner reaches a second preset time, calculating a second high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger;
judging the range of a first ratio between the second high-low pressure ratio and the first high-low pressure ratio;
selectively executing oil return operation of the indoor unit according to the judgment result;
the second preset time length is longer than the first preset time length;
the step of selectively executing the oil return operation of the indoor unit according to the judgment result further comprises the following steps:
if the first ratio is larger than or equal to a first threshold value, executing oil return operation of the indoor unit;
the step of selectively executing the oil return operation of the indoor unit according to the judgment result further comprises the following steps:
if the first ratio is smaller than the first threshold value and larger than or equal to a second threshold value, acquiring a first operating frequency of the compressor;
judging the magnitude of the first operating frequency and the first oil return frequency;
if the first operation frequency is less than the first oil return frequency, controlling the compressor to be in an up-conversion operation to the first oil return frequency;
when the compressor continuously operates at the first oil return frequency for a third preset time length, calculating a third high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger;
judging the range of a second ratio between the third high-low pressure ratio and the second high-low pressure ratio;
and selectively executing the oil return operation of the indoor unit according to the judgment result.
2. The indoor unit oil return control method according to claim 1, wherein the step of selectively performing the indoor unit oil return operation according to the determination result further includes:
if the second ratio is smaller than the first threshold and larger than or equal to the second threshold, controlling the compressor to increase the frequency to a second oil return frequency for operation;
calculating a fourth high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger when the compressor continuously operates at the second oil return frequency for a fourth preset time length;
judging the range of a third ratio between the fourth high-low pressure ratio and the third high-low pressure ratio;
selectively executing oil return operation of the indoor unit according to the judgment result; and/or
And if the second ratio is smaller than the second threshold value, controlling the air conditioner to keep the current running state, and executing the oil return operation of the indoor unit until the ratio between the high-low pressure ratio and the high-low pressure ratio calculated twice is larger than or equal to the first threshold value.
3. The indoor unit oil return control method according to claim 2, wherein the step of selectively performing the indoor unit oil return operation according to the determination result further includes:
if the third ratio is smaller than the first threshold and larger than or equal to the second threshold, executing oil return operation of the indoor unit; and/or
And if the third ratio is smaller than the second threshold, controlling the air conditioner to keep the current running state, and executing the oil return operation of the indoor unit until the ratio between the high-low pressure ratio and the high-low pressure ratio calculated twice is larger than or equal to the first threshold.
4. The indoor unit oil return control method according to claim 2, characterized by further comprising:
if the first operating frequency is greater than or equal to the first oil return frequency, further judging the magnitude of the first operating frequency and the second oil return frequency;
if the first operation frequency is smaller than the second oil return frequency, controlling the compressor to increase the frequency to the second oil return frequency for operation;
calculating a fifth high-low pressure ratio between the pressure of the outdoor heat exchanger and the pressure of the indoor heat exchanger when the compressor continuously operates at the second oil return frequency for a fifth preset time duration;
judging the range of a fourth ratio between the fifth high-low pressure ratio and the second high-low pressure ratio;
selectively executing oil return operation of the indoor unit according to the judgment result; and/or
And if the first operating frequency is greater than or equal to the second oil return frequency, controlling the air conditioner to keep the current operating state until the ratio of the high-low pressure ratio calculated twice is greater than or equal to the first threshold value, and executing the oil return operation of the indoor unit.
5. The indoor unit oil return control method according to claim 4, wherein the step of selectively performing the indoor unit oil return operation according to the determination result further includes:
if the fourth ratio is smaller than the first threshold and larger than or equal to the second threshold, executing oil return operation of the indoor unit; and/or
And if the fourth ratio is smaller than the second threshold value, controlling the air conditioner to keep the current running state, and executing the oil return operation of the indoor unit when the ratio between the high-pressure ratio and the low-pressure ratio calculated twice is larger than or equal to the first threshold value.
6. The indoor unit oil return control method according to claim 1, wherein the step of selectively performing an indoor unit oil return operation according to the determination result further includes:
and if the first ratio is smaller than the second threshold value, the oil return operation of the indoor unit is not executed, and the air conditioner is controlled to keep the current running state.
7. The indoor unit oil return control method according to claim 1, wherein the step of performing an indoor unit oil return operation further comprises:
controlling the compressor to reduce the frequency to a first reversing frequency;
controlling the four-way valve to change direction to convert into a heating mode;
after the four-way valve is switched, controlling the indoor fan to continuously run for a sixth preset time and then closing the indoor fan;
controlling the compressor to increase the frequency to a third oil return frequency;
and controlling the on-off valve to be opened, and opening the throttling device to the maximum opening degree.
8. The indoor unit oil return control method according to claim 7, wherein after the step of "controlling the on-off valve to be opened and the throttle device to be opened to the maximum opening degree", the control method further comprises:
after the on-off valve is opened and lasts for a seventh preset time, controlling the compressor to reduce the frequency to a second reversing frequency;
controlling the four-way valve to change direction to convert into a refrigeration mode;
controlling the indoor fan to start and operate;
determining a second operating frequency based on the set temperature, and controlling the compressor to operate according to the second operating frequency;
and controlling the on-off valve to close.
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| CN202110778994.XA CN113483449B (en) | 2021-07-09 | 2021-07-09 | Oil return control method for indoor unit |
| PCT/CN2021/129819 WO2023279616A1 (en) | 2021-07-09 | 2021-11-10 | Indoor unit oil return control method |
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| CN115950067A (en) * | 2022-12-05 | 2023-04-11 | 珠海格力电器股份有限公司 | Air conditioning system, oil return control method and device thereof, and storage medium |
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| Publication number | Publication date |
|---|---|
| CN113483449A (en) | 2021-10-08 |
| WO2023279616A1 (en) | 2023-01-12 |
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