CN113551388B - Self-cleaning control method in outdoor unit pipe of air conditioning system - Google Patents

Abstract

The invention relates to the technical field of air conditioners, in particular to a self-cleaning control method in an outdoor unit pipe of an air conditioning system. The invention aims to solve the problem that the heat exchange effect of an outdoor heat exchanger is influenced because the refrigerator oil is easy to carbonize at high temperature. To this end, the method for controlling self-cleaning in the outdoor unit tube of the present invention comprises: after the air conditioning system runs for a set time, acquiring the inlet pressure and the outlet pressure of the outdoor heat exchanger; calculating an inlet-outlet pressure difference based on the inlet pressure and the outlet pressure of the outdoor heat exchanger; comparing the inlet-outlet pressure difference with a pressure difference threshold value; and selectively controlling the air conditioning system to execute the self-cleaning mode in the outdoor unit pipe based on the comparison result. Through the control mode, the method for controlling the self-cleaning in the outdoor unit pipe can remove impurities accumulated in the outdoor heat exchanger pipe, ensures that the pipe is clean and free of foreign matters, improves the overall heat exchange effect and efficiency of the outdoor heat exchanger, guarantees the service life sustainability of the outdoor heat exchanger, and improves user experience.

Description

Self-cleaning control method in outdoor unit pipe of air conditioning system

technical field

The invention relates to the technical field of air conditioning, in particular to a self-cleaning control method in an outdoor unit pipe of an air conditioning system.

Background technique

The compressor is usually filled with refrigerating machine oil. During the operation of the air conditioning system, the refrigerating machine oil flows into the heat exchanger of the outdoor unit together with the refrigerant. Affected by the high temperature and wear of the compressor, the refrigerating machine oil will be carbonized at high temperature, and carbon substances will be precipitated from the refrigerating machine oil mixture and become impurities. However, the heat exchange copper tubes of existing outdoor heat exchangers are generally internally threaded copper tubes. The zigzag shape in the tube hinders the movement of impurities. Over time, the impurities accumulate in the tubes, hindering the heat exchange between the refrigerant and the outside world. As a result, the heat exchange area and temperature difference of the outdoor heat exchanger are reduced, and the heat exchange efficiency is reduced, which indirectly affects the user experience of indoor users.

For the above problems, there is no practical and effective solution in the prior art.

Correspondingly, there is a need in the art for a new self-cleaning control method in the pipe of an outdoor unit of an air-conditioning system to solve the above problems.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, that is, to solve the problem that the refrigerating machine oil is easily carbonized at high temperature and affects the heat exchange effect of the outdoor heat exchanger, the present invention provides a self-cleaning control method in the pipe of the outdoor unit of the air-conditioning system. The air conditioning system includes a compressor, an outdoor heat exchanger, an outdoor fan, a first throttling element, an indoor heat exchanger, an indoor fan, and an oil controller. The oil control device includes a housing and an inlet pipe, an outlet pipe and an oil return pipe arranged in the housing, the oil return pipe communicates with the inlet of the liquid reservoir, and the oil return pipe communicates with the liquid reservoir A second throttling element is set between the inlets,

The self-cleaning control method in the pipe of the outdoor unit includes:

Obtain the inlet pressure and outlet pressure of the outdoor heat exchanger after the air conditioning system has been running for a set time;

calculating the pressure difference between the inlet and outlet based on the inlet pressure and outlet pressure of the outdoor heat exchanger;

Comparing the pressure difference between the inlet and outlet with the pressure difference threshold;

Based on the comparison result, selectively controlling the air conditioning system to execute the self-cleaning mode in the pipe of the outdoor unit;

Wherein, when the self-cleaning mode in the pipe of the outdoor unit is running, at least part of the impurities in the outdoor heat exchanger can flow into the accumulator together with the refrigerant and the refrigerating machine oil.

In the preferred technical solution of the self-cleaning control method of the outdoor unit duct of the above-mentioned air conditioning system, the step of "selectively controlling the air conditioning system to perform the self-cleaning mode in the duct of the outdoor unit based on the comparison result" further includes:

When the pressure difference between the inlet and outlet is greater than or equal to the pressure difference threshold, the air conditioning system is controlled to execute the self-cleaning mode in the pipe of the outdoor unit.

In the preferred technical solution of the self-cleaning control method of the outdoor unit pipe of the above-mentioned air-conditioning system, the step of "selectively controlling the air-conditioning system to perform the self-cleaning mode in the outdoor unit pipe based on the comparison result" further includes:

When the pressure difference between the inlet and outlet is less than the pressure difference threshold, the air conditioning system is controlled to maintain the current operating state.

In the preferred technical solution of the self-cleaning control method of the outdoor unit pipe of the above-mentioned air-conditioning system, the step of "controlling the air-conditioning system to execute the self-cleaning mode in the outdoor unit pipe" further includes:

Obtain the working mode of the air conditioning system;

When the air-conditioning system operates in cooling mode, control the air-conditioning system to perform the first self-cleaning step in the pipe;

When the air-conditioning system operates in a heating mode, the air-conditioning system is controlled to perform a second self-cleaning step in the pipe.

In the preferred technical solution of the self-cleaning control method in the outdoor unit pipe of the above-mentioned air-conditioning system, the first self-cleaning step in the pipe includes:

Control the air conditioning system to adjust to the following state and continue to run for a first set time: the compressor runs at the first set frequency, the outdoor fan runs at the maximum wind speed, the indoor fan runs at the natural wind mode, all said first throttle element and said second throttle element are closed;

Controlling the air conditioning system to adjust to the following state and continue to run for a second set duration: the compressor stops running, the outdoor fan stops running, the indoor fan runs in natural wind mode, and the first throttling element is closed , the second throttling element operates at the maximum opening degree.

In the preferred technical solution of the self-cleaning control method in the outdoor unit pipe of the above-mentioned air-conditioning system, the second self-cleaning step in the pipe includes:

Controlling the air conditioning system to adjust to the following state and continue to run for a third set duration: the compressor runs at a second set frequency, the outdoor fan runs at a minimum wind speed, the indoor fan runs at a low wind speed, the The first throttling element operates at the maximum opening degree, and the second throttling element is closed;

Controlling the air conditioning system to adjust to the following state and continue to run for a fourth set time period: the compressor stops running, the outdoor fan and the indoor fan both stop running, the first throttling element is closed, the second Two throttling elements operate at the maximum opening;

Wherein, the rotation speed of the outdoor fan when operating at the low wind speed is greater than the rotation speed when operating at the minimum wind speed.

In the preferred technical solution of the self-cleaning control method in the outdoor unit pipe of the above-mentioned air-conditioning system, the self-cleaning control method in the outdoor unit pipe also includes:

After the self-cleaning mode in the pipe of the outdoor unit is completed, the air-conditioning system is controlled to return to the state before the self-cleaning mode in the pipe of the outdoor unit is executed to continue running.

In the preferred technical solution of the self-cleaning control method in the outdoor unit pipe of the above-mentioned air-conditioning system, the following formula is used to calculate the pressure difference between the inlet and outlet:

P=ABS(P _con-in - P _con-out )

Wherein, the P is the pressure difference between the inlet and outlet; the P _con-in is the inlet pressure of the outdoor heat exchanger; P _con-out is the outlet pressure of the outdoor heat exchanger.

In the preferred technical solution of the self-cleaning control method in the pipe of the outdoor unit of the above-mentioned air conditioning system, the inlet pipe communicates with the outlet of the outdoor heat exchanger, the outlet pipe communicates with the inlet of the indoor heat exchanger, and the The first throttling element is arranged between the outlet pipe and the inlet of the indoor heat exchanger.

In the preferred technical solution of the self-cleaning control method in the pipe of the outdoor unit of the above-mentioned air conditioning system, the first throttling element is an electronic expansion valve; and/or the second throttling element is an electronic expansion valve or a controllable opening The electromagnetic valve.

Those skilled in the art can understand that, in the preferred technical solution of the present invention, the air conditioning system includes a compressor, an outdoor heat exchanger, an outdoor fan, a first throttling element, an indoor heat exchanger, an indoor fan and an oil controller, and the compression The engine is equipped with a liquid reservoir, and a filter is arranged in the liquid reservoir. The oil control device includes a casing and an inlet pipe, an outlet pipe and an oil return pipe arranged on the casing. The oil return pipe is connected with the inlet of the liquid reservoir, and the oil return pipe is connected with the A second throttling element is arranged between the inlets of the liquid tank, and the self-cleaning control method in the outdoor unit pipe includes: obtaining the inlet pressure and outlet pressure of the outdoor heat exchanger after the air conditioning system runs for a set time; Inlet pressure and outlet pressure, calculate the inlet and outlet pressure difference; compare the size of the inlet and outlet pressure difference and the pressure difference threshold; based on the comparison result, selectively control the air conditioning system to implement the self-cleaning mode in the outdoor unit pipe; where, when the outdoor unit pipe self-cleaning When operating in the refrigerating mode, at least part of the impurities in the outdoor unit can flow into the accumulator together with the refrigerant and the refrigerating machine oil.

Through the above-mentioned control method, the self-cleaning control method in the pipe of the outdoor unit of the present application can remove the impurities accumulated in the pipe of the outdoor heat exchanger, ensure that the pipe is clean and free of foreign matter, improve the overall heat exchange effect and efficiency of the outdoor heat exchanger, and ensure that the outdoor heat exchanger Heater life sustainability, improve user experience.

Specifically, by comparing the pressure difference between the inlet and outlet of the outdoor heat exchanger and the pressure difference threshold, the circulation resistance of the refrigerant in the pipeline of the outdoor heat exchanger can be reflected. When the threshold value is reached, it indicates that the pressure drop between the inlet and outlet of the outdoor heat exchanger is too large, that is, the flow resistance of the refrigerant is too large. Clean the inside of the pipeline to remove the accumulation of impurities. At this time, by controlling the air conditioning system to execute the self-cleaning mode in the pipe of the outdoor unit, the impurities accumulated in the outdoor heat exchanger can flow into the accumulator along with the refrigerant and refrigerating machine oil, and then filter the impurities with the help of the filter set inside the accumulator , so that the filtered refrigerant and refrigerating machine oil are relatively clean and contain less impurities, and finally realize the cleaning of the tube of the outdoor heat exchanger, improve the heat exchange area and heat exchange effect of the outdoor heat exchanger, and ensure that the air conditioning system is always at a high level work efficiency and improve user experience.

Further, by selecting the control method of performing the first self-cleaning step in the pipe or the second self-cleaning step in the pipe based on the working mode of the air-conditioning system, the control method of the present application can also adopt different cleaning methods based on different working modes. method, so as to improve the self-cleaning effect in the tube under each working mode under the premise of ensuring the user experience.

Description of drawings

The self-cleaning control method in the pipe of the outdoor unit of the air conditioning system of the present invention will be described below with reference to the accompanying drawings. In the attached picture:

Fig. 1 is the system diagram of the air conditioning system of the present invention;

Fig. 2 is the flowchart of the self-cleaning control method in the pipe of the outdoor unit of the air conditioning system of the present invention;

Fig. 3 is a logic diagram of the self-cleaning control method in the pipe of the outdoor unit of the air conditioning system of the present invention.

List of reference signs

1. Compressor; 2. Four-way valve; 3. Outdoor heat exchanger; 4. First throttling element; 5. Bridge rectifier pipeline; 6. Oil controller; 61. Inlet pipe; 62. Outlet pipe; 63 , Oil return pipe; 7, Indoor heat exchanger; 8, Second throttling element; 9, Liquid reservoir.

detailed description

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention, and are not intended to limit the protection scope of the present invention. For example, although the steps of the method of the present invention are described in detail below, under the premise of not departing from the basic principle of the present invention, those skilled in the art can combine, split and exchange the above steps, so that the modified technical solution It does not change the basic idea of the present invention, so it also falls within the protection scope of the present invention.

It should be noted that, in the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" etc. The terms of the indicated direction or positional relationship are based on the direction or positional relationship shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation , and therefore cannot be construed as a limitation of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

In addition, it should be noted that, in the description of the present invention, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a It is a detachable connection or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediary, and it may be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

Referring first to Fig. 1, the structure of the air conditioning system of the present invention will be described.

As shown in Figure 1, Figure 1 shows the system diagram of the air-conditioning system. In this application, the air-conditioning system includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a first throttling element 4, and a bridge rectifier Road 5, oil controller 6, indoor heat exchanger 7, second throttling element 8 and liquid reservoir 9. The oil controller 6 includes a housing and an inlet pipe 61, an outlet pipe 62 and an oil return pipe 63 arranged on the housing. The inlet pipe 61 extends from the top of the housing, and the outlet pipe 62 and the oil return pipe 63 extend from the bottom of the housing. , and the protruding height of the outlet pipe 62 is greater than the protruding height of the oil return pipe 63 . The bridge rectification pipeline 5 is composed of four pipelines to form a bridge structure, and each pipeline is provided with a one-way valve (5a-5d). A filter screen is arranged in the liquid reservoir 9, and the filter screen can filter other impurities on the basis of allowing the refrigerant and the refrigerating machine oil to penetrate. In this application, the first throttling element 4 is an electronic expansion valve, and the second throttling element 8 may be an electronic expansion valve or a solenoid valve with a controllable opening.

Referring to Figure 1, when the air conditioning system is in cooling mode, the exhaust port of the compressor 1 is connected to the inlet of the outdoor heat exchanger 3 through the four-way valve 2, and the outlet of the outdoor heat exchanger 3 is connected to the one-way bridge rectifier pipeline 5. The valve 5a communicates with the inlet pipe 61 of the oil controller 6, the outlet pipe 62 of the oil controller 6 communicates with the inlet of the first throttling element 4, and the outlet of the first throttling element 4 communicates with the outlet of the indoor heat exchanger 7 through the one-way valve 5c. The inlet is connected, and the outlet of the indoor heat exchanger 7 is connected with the inlet of the accumulator 9 after passing through the four-way valve 2, and the outlet of the accumulator 9 is connected with the suction port of the compressor 1. The oil return pipe 63 of the oil controller 6 communicates with the inlet of the liquid reservoir 9 through the second throttling element 8 .

When the air conditioning system is in cooling operation, the gaseous refrigerant mixed with refrigerating machine oil discharged from the compressor 1 enters the outdoor heat exchanger 3 through the four-way valve 2 and is liquefied into a liquid refrigerant. The liquid refrigerant enters the oil control through the check valve 5a and the inlet pipe 61 Inside the housing of device 6. The liquid refrigerant entering the oil controller 6 will have a small amount of flash, and most of it is still in a liquid state. In the oil controller 6, the refrigerating machine oil will be layered with the liquid refrigerant. The refrigerating machine oil is in the lower layer, the middle layer is liquid refrigerant, and the upper layer is gaseous refrigerant. After the gaseous and liquid refrigerants are throttled by the outlet pipe 62 and the first throttling element 4, they enter the indoor heat exchanger 7 through the check valve 5c and are vaporized into gaseous refrigerants. The gaseous refrigerants pass through the four-way valve 2 and the liquid receiver 9 Enter the suction port of compressor 1 to realize the circulation of refrigerant. The refrigerating machine oil in the lowermost layer of the oil controller 6 enters the suction port of the compressor 1 after passing through the second throttling element 8 and the liquid reservoir 9 to realize the circulation of the refrigerating machine oil.

Continuing to refer to Fig. 1, in the heating mode, the exhaust port of compressor 1 is connected to the inlet of indoor heat exchanger 7 through four-way valve 2, and the outlet of indoor heat exchanger 7 is connected to the single channel of bridge rectifier pipeline 5. The direction valve 5b communicates with the inlet pipe 61 of the oil controller 6, the outlet pipe 62 of the oil controller 6 communicates with the inlet of the first throttling element 4, and the outlet of the first throttling element 4 communicates with the outdoor heat exchanger 3 through the one-way valve 5d. The inlet of the outdoor heat exchanger 3 is communicated with the inlet of the accumulator 9 after passing through the four-way valve 2, and the outlet of the accumulator 9 is communicated with the suction port of the compressor 1. The oil return pipe 63 of the oil controller 6 communicates with the inlet of the liquid reservoir 9 through the second throttling element 8 .

When the air conditioning system is in heating operation, the gaseous refrigerant mixed with refrigerating machine oil discharged from the compressor 1 enters the indoor heat exchanger 7 through the four-way valve 2 and is liquefied into a liquid refrigerant. The liquid refrigerant enters through the one-way valve 5b and the inlet pipe 61 Inside the housing of oil controller 6. The liquid refrigerant entering the oil controller 6 will have a small amount of flash, and most of it is still in a liquid state. In the oil controller 6, the refrigerating machine oil will be layered with the liquid refrigerant. The refrigerating machine oil is in the lower layer, the middle layer is liquid refrigerant, and the upper layer is gaseous refrigerant. After the gaseous and liquid refrigerants are throttled by the outlet pipe 62 and the first throttling element 4, they enter the outdoor heat exchanger 3 through the one-way valve 5d and are vaporized into gaseous refrigerants. The gaseous refrigerants pass through the four-way valve 2 and the liquid receiver 9 Enter the suction port of compressor 1 to realize the circulation of refrigerant. The refrigerating machine oil in the lowermost layer of the oil controller 6 enters the suction port of the compressor 1 after passing through the second throttling element 8 and the liquid reservoir 9 to realize the circulation of the refrigerating machine oil.

Those skilled in the art can understand that although the air-conditioning system of the present application is introduced in conjunction with the above-mentioned specific setting methods, this is not intended to limit the scope of protection of the present application. Personnel can add or delete one or several components, or adjust the setting position of one or several components on the basis of the above-mentioned setting methods. For example, the oil controller 6 can also be replaced with other structures in the prior art, and its setting position can also be between the rotary compressor 1 and the outdoor heat exchanger 3 . For another example, the four-way valve 2 may not be provided in the air-conditioning system, and accordingly the bridge rectifier pipeline 5 also needs to be deleted by two pipelines.

In addition, although the specific structure of the accumulator 9 is not discussed in this application, it is not that the disclosure of this application is insufficient. Those skilled in the art can understand that as long as the process of passing through the refrigerant and refrigerating machine oil can be satisfied, For the conditions of filtering impurities and making the filtered refrigerating machine oil and gaseous refrigerant return to the compressor smoothly, any structure of the accumulator can be applied to this application.

The self-cleaning control method in the pipe of the outdoor unit of the air conditioning system of the present invention will be introduced below with reference to FIG. 2 and FIG. 3 . Wherein, FIG. 2 is a flow chart of the self-cleaning control method of the outdoor unit duct of the air conditioning system of the present invention; FIG. 3 is a logic diagram of the self-cleaning control method of the outdoor unit duct of the air conditioning system of the present invention.

As mentioned in the background art, in the prior art, refrigerating machine oil is prone to high-temperature carbonization due to the high temperature and wear of the compressor, and carbon substances will be precipitated from the refrigerating machine oil mixture and become impurities and circulate in the system along with the refrigerant. However, because most of the outdoor heat exchangers are internally threaded copper tubes, their internal structure easily hinders the movement of impurities, resulting in the accumulation of impurities. The heat exchange effect of the heater decreases, and the heat exchange efficiency decreases, which affects the user experience. In order to solve the above problems, the self-cleaning control method in the outdoor unit pipe of the air conditioning system of the present application mainly includes the following steps:

S100. Obtain the inlet pressure and outlet pressure of the outdoor heat exchanger after the air conditioning system has been running for a set time; The pressure sensor on the pipeline obtains the inlet pressure and outlet pressure of the outdoor heat exchanger respectively. Of course, the specific value of the set time and the pressure collection method are not unique, and can be adjusted by those skilled in the art. The purpose of setting the time is to collect pressure data after the air-conditioning system runs stably, so as to ensure the accuracy of data collection and the determination of pressure. The temperature can also be collected by a temperature sensor and obtained through the corresponding relationship between temperature and pressure.

S200. Calculate the inlet and outlet pressure difference based on the inlet pressure and outlet pressure of the outdoor heat exchanger; for example, calculate the inlet and outlet pressure difference by calculating the absolute value of the difference between the inlet pressure and the outlet pressure (such as using the ABS function) . Of course, the inlet and outlet pressure difference can also be obtained by subtracting the smaller value from the larger value of the inlet pressure and the outlet pressure.

S300. Compare the inlet and outlet pressure difference with the pressure difference threshold; for example, after calculating the inlet and outlet pressure difference, compare the inlet and outlet pressure difference with the pressure difference threshold by comparing the difference or ratio between the two.

S400. Based on the comparison result, selectively control the air conditioning system to execute the self-cleaning mode in the outdoor unit duct; for example, when the comparison result shows that the pressure difference between the inlet and outlet is greater than or equal to the pressure difference threshold, control the air conditioning system to implement the self-cleaning mode in the outdoor unit duct.

Among them, it should be noted that in this application, when the self-cleaning mode in the pipe of the outdoor unit is running, at least part of the impurities in the pipeline of the outdoor heat exchanger can be taken away by the flow and flushing action of the refrigerant and refrigerating machine oil and mixed with the refrigerant and refrigerating machine oil. Refrigerator oil flows into the reservoir together.

From the above description, it can be seen that the self-cleaning control method in the pipe of the outdoor unit of the present application can remove the accumulated impurities in the pipes of the system, especially in the pipes of the outdoor heat exchanger, by running the self-cleaning mode in the pipes of the outdoor unit, so as to ensure that the pipes are clean and free of foreign matter , improve the overall heat exchange effect and efficiency of the outdoor heat exchanger, ensure the sustainability of the life of the outdoor heat exchanger, and improve user experience.

Specifically, by comparing the pressure difference between the inlet and outlet of the outdoor heat exchanger with the pressure difference threshold, the circulation resistance of the refrigerant in the pipeline can be reflected. When the pressure difference between the inlet and outlet is greater than or equal to the pressure difference threshold, it indicates that the outdoor The pressure drop between the inlet and outlet of the heat exchanger is too large, that is, the flow resistance of the refrigerant is too large. This result is caused by excessive accumulation of impurities in the pipeline and hindering the circulation of the refrigerant. Clean to remove accumulated impurities. At this time, by controlling the air conditioning system to execute the self-cleaning mode in the pipe of the outdoor unit, the refrigerant and refrigerating machine oil can take away the accumulated impurities in the outdoor heat exchanger under the action of high-speed flow and flushing, and flow into the storage liquid together with the refrigerant and refrigerating machine oil Then filter the impurities with the help of the filter set inside the liquid receiver, so that the filtered refrigerant and refrigerating machine oil are relatively clean and contain less impurities, so as to realize the cleaning of the tubes of the outdoor heat exchanger and improve the efficiency of the outdoor heat exchanger. The heat exchange area and heat exchange effect ensure that the outdoor heat exchanger is always at a high working efficiency.

The self-cleaning control method in the pipe of the outdoor unit of the air conditioning system of the present application will be discussed in detail below.

In a more preferred implementation, step S400 further includes: when the pressure difference between the inlet and outlet is greater than or equal to the pressure difference threshold, control the air conditioning system to execute the self-cleaning mode in the pipe of the outdoor unit; when the inlet and outlet pressure difference is less than the pressure difference threshold, control The air conditioning system remains in its current operating state.

Specifically, when the pressure difference between the inlet and outlet is greater than or equal to the pressure difference threshold, it indicates that the pressure drop between the inlet and outlet of the outdoor heat exchanger is too large. In other words, the circulation resistance of the refrigerant in the outdoor heat exchanger is too large. This result is due to Excessive accumulation of impurities in the pipeline of the outdoor heat exchanger hinders the circulation of the refrigerant. Therefore, it is necessary to clean the inside of the pipeline of the outdoor heat exchanger to remove the accumulated impurities. When the inlet and outlet pressure difference is less than the pressure difference threshold, it indicates that the pressure drop between the inlet and outlet of the outdoor heat exchanger is small, and the refrigerant circulation is normal, so there is no need to clean the outdoor heat exchanger, just keep the current operating state of the air conditioning system .

In another preferred embodiment, since the operating mode of the air conditioning system determines the flow direction of the refrigerant in the system, and the flow direction of the refrigerant has a decisive impact on the cleaning method, before cleaning the outdoor heat exchanger, it is necessary to First determine the current operating mode of the air conditioning system, and based on the operating mode, specifically determine the specific cleaning steps of the self-cleaning mode in the outdoor unit pipe. That is to say, the step of controlling the air-conditioning system to execute the self-cleaning mode of the outdoor unit further includes: obtaining the working mode of the air-conditioning system; mode, control the air conditioning system to perform the second self-cleaning step in the pipe.

Before describing the first in-pipe self-cleaning step and the second in-pipe self-cleaning step, it should first be explained that the indoor fans of existing air-conditioning systems usually include multiple wind speeds. In order to make the following description clearer, the indoor The wind speed of the fan is divided according to the rotation speed from low to high as follows: minimum wind speed < low wind speed < medium wind speed < high wind speed < maximum wind speed. Among them, the minimum wind speed and maximum wind speed correspond to the minimum speed and maximum speed of the indoor fan respectively (the same is true for the outdoor fan). In addition, the fan in this embodiment also has a natural wind mode. In this mode, the wind speed and air volume of the fan are random and non-repetitive, but are closest to nature. Certainly, the purpose of the above division methods is to describe the technical solution of the present application more clearly, but not to limit the protection scope of the present application. Without departing from the principles of the present application, those skilled in the art can use other division methods to re-divide the wind speed of the indoor fan.

The two self-cleaning steps are described in detail below. When the air-conditioning system operates in cooling mode, the step of controlling the air-conditioning system to perform the first self-cleaning in the pipe further includes: controlling the air-conditioning system to adjust to the following state and continue to run for the first set time: the compressor runs at the first set frequency, the outdoor fan runs at the first set frequency The maximum wind speed is running, the indoor fan is running in natural wind mode, the first throttling element and the second throttling element are closed; then control the air conditioning system to adjust to the following state and continue to run for the second set time: the compressor stops running, the outdoor fan stops running, the indoor fan operates in natural wind mode, the first throttling element is closed, and the second throttling element operates at the maximum opening.

For example, when the air conditioning system is in cooling mode, the flow direction of the refrigerant is compressor→outdoor heat exchanger→oil controller→first throttling element→indoor heat exchanger→accumulator→compressor, and the flow direction of refrigerating machine oil is Compressor→outdoor heat exchanger→oil controller→second throttling element→accumulator→compressor. Since the refrigerant flows through the outdoor heat exchanger first, the outdoor heat exchanger can be cleaned ingeniously by means of a cycle composed of compressor→outdoor heat exchanger→oil controller→accumulator→compressor. At this time, firstly, the compressor is controlled to run at the first set frequency, and the first set frequency may be a higher frequency, so that the pressure in the system is higher, so as to speed up the flow rate of the refrigerant. Wherein, the specific numerical value of the first set frequency can be obtained through experiments, and is not specifically limited in this embodiment. Driven by the high frequency of the compressor, the gaseous refrigerant enters the outdoor heat exchanger through the four-way valve. At this time, the outdoor fan runs at the maximum wind speed, and the heat exchange between the gaseous refrigerant entering the outdoor heat exchanger and the air is intense and rapidly condensed into The liquid refrigerant flows quickly under high pressure to wash the heat exchange copper tube, taking away the impurities in the heat exchange copper tube and entering the oil control device through the inlet pipe of the oil control device. At this time, since the first throttling element and the second throttling element are both closed, liquid refrigerant and impurities accumulate in the oil controller, and the pressure in the oil controller rises. When the above operating state lasts for the first set time, the pressure in the oil controller rises to a higher value. At this time, the control compressor stops running, the outdoor fan stops running, the first throttling element remains closed, and the second throttling element keeps closed. Operating at the maximum opening, under the action of pressure, the refrigerant, refrigerating machine oil and impurities in the oil controller flow back into the accumulator through the oil return pipe and the second throttling element, and filter the impurities with the help of the filter inside the accumulator . After the second set time period, the liquid refrigerant, refrigerating machine oil and impurities in the oil controller are basically completely refluxed. At this time, the refrigerant and refrigerating machine oil in the accumulator are relatively clean, realizing the self-cleaning of the outdoor unit in the tube under cooling conditions. During the operation of the self-cleaning mode in the first pipe, in order to ensure the experience of indoor users, the indoor fan always operates in the natural wind mode.

When the air-conditioning system operates in the heating mode, the step of controlling the air-conditioning system to perform the second self-cleaning in the pipe further includes: controlling the air-conditioning system to adjust to the following state and continue to run for a third set duration: the compressor runs at the second set frequency, the outdoor fan Run at the minimum wind speed, the indoor fan runs at low wind speed, the first throttling element runs at the maximum opening, and the second throttling element closes; then control the air conditioning system to adjust to the following state and continue to run for the fourth set time: the compressor stops running, both the outdoor fan and the indoor fan stop running, the first throttling element is closed, and the second throttling element is running at the maximum opening.

For example, when the air conditioning system operates in heating mode, the flow direction of the refrigerant is compressor→indoor heat exchanger→oil controller→first throttling element→outdoor heat exchanger→accumulator→compressor. Since the refrigerant flows through the indoor heat exchanger first and then through the outdoor heat exchanger, the outdoor heat exchanger can be cleaned by means of a normal refrigerant circulation circuit. At this time, firstly, the compressor is controlled to run at the second set frequency, and the second set frequency may be a higher frequency, so that the pressure in the system is higher, so as to speed up the flow rate of the refrigerant. Wherein, the specific value of the second set frequency can be obtained through experiments, and is not specifically limited in this embodiment. Driven by the high frequency of the compressor, the gaseous refrigerant enters the indoor heat exchanger through the four-way valve. At this time, the indoor fan operates at a low wind speed, which can balance the condensation effect of the refrigerant and the heat exchange effect in the room. The gaseous refrigerant entering the indoor heat exchanger exchanges heat with the air and condenses into a liquid refrigerant, which quickly flows into the oil controller. At this time, since the first throttling element operates at the maximum opening and the second throttling element is closed, the boiling point of the liquid refrigerant does not drop significantly when it enters the outdoor heat exchanger, and the evaporation process of the refrigerant in the outdoor heat exchanger is not violent , and the outdoor unit runs at the minimum wind speed, the heat exchange between the refrigerant and the outdoor air is not strong, so part of the refrigerant still flows through the outdoor heat exchanger in a liquid state, and flushes the heat transfer copper tube during the flow, and the heat transfer Impurities in the copper tube are taken away and returned to the accumulator through the four-way valve. The refrigerant mixed with refrigerating machine oil and impurities is filtered by the filter inside the accumulator, and then re-enters the compressor to participate in the cycle. When the above operating state lasts for the third set time, all the refrigerant circulates in the air conditioning system once or more times, at this time, the control compressor stops running, the outdoor fan and the indoor fan stop running, the first throttling element remains closed, The second throttling element operates at the maximum opening. Under the action of pressure, the refrigerant, refrigerating machine oil and a small part of impurities in the oil controller flow back into the accumulator through the oil return pipe and the second throttling element. The internal filter screen filters impurities. After the fourth set time, the liquid refrigerant, refrigerating machine oil and impurities in the oil controller are basically backflowed. At this time, the refrigerant and refrigerating machine oil in the system are relatively clean, realizing the self-cleaning of the pipe of the outdoor unit under heating conditions. During the operation of the self-cleaning step in the second pipe, in order to ensure the cleaning effect without greatly sacrificing the experience of indoor users, when the compressor is running at the second set frequency, the indoor fan is controlled to run at a low wind speed. When shutting down, control the indoor fan to stop running to prevent the air conditioner from blowing cold air.

It can be seen from the above description that the present application controls the compressor, the indoor fan, the outdoor fan, the first throttling element and the second throttling element to operate in different working states in the cooling mode and the heating mode, and can clean the air in a balanced manner. Under the premise of effective and indoor user experience, the self-cleaning of the outdoor heat exchanger tube can be realized to ensure the heat exchange area and heat exchange effect of the cleaned outdoor heat exchanger, so that the outdoor heat exchanger can always work at a high efficiency and improve user experience.

In another preferred embodiment, the method for controlling the self-cleaning in-pipe of the outdoor unit further includes: after the self-cleaning mode in the outdoor unit is completed, controlling the air-conditioning system to return to the state before the self-cleaning mode in the outdoor unit is executed to continue running. Specifically, after running the self-cleaning mode in the outdoor unit tube, the impurities in the outdoor heat exchanger have been removed. At this time, the air conditioner can be controlled to return to the operating state before the self-cleaning mode in the outdoor unit tube to ensure the user experience .

In another preferred implementation, the following formula can be used to calculate the pressure difference between the inlet and outlet:

P=ABS ( P _con-in - P _con-out ) (1)

In the formula (1), P is the pressure difference between the inlet and outlet, P _con-in is the inlet pressure of the outdoor heat exchanger; P _con-out is the outlet pressure of the outdoor heat exchanger.

It should be noted that, in the above description, although the pressure difference threshold, the first to fourth set time lengths, the first/second set frequency, etc. have not given specific values, this does not mean that the disclosure of the present application is insufficient, on the contrary , those skilled in the art can set the above parameters experimentally or empirically based on the specific application scenarios of the air-conditioning system, so that the control method can better exert its efficacy.

A possible implementation process of the control method of the present invention will be introduced below with reference to FIG. 3 . Wherein, FIG. 3 is a logic diagram of the self-cleaning control method in the pipe of the outdoor unit of the air-conditioning system of the present invention.

As shown in Figure 3, in a possible implementation, after the air conditioner is started, step S10 is first performed: obtain the running time t → after obtaining the running time t , perform step S20: compare the running time t with 3min → if t ≥ 3min , then execute step S30: obtain the inlet pressure P _con-in and outlet pressure P _con-out of the outdoor heat exchanger → after obtaining the above parameters, execute step S40: use the formula (1) to calculate the temperature difference P between the inlet and outlet → calculate the inlet and outlet After the temperature difference, execute step S50: compare the inlet and outlet pressure difference P with the pressure difference threshold △P → when P≥△P is established, execute step S60: judge whether the working mode of the air conditioner is cooling mode → if the judgment result is yes, Then perform step S61: perform the first self-cleaning step in the pipe → otherwise, perform step S70: judge whether the air-conditioning system is in heating mode → if the judgment result is yes, perform step S71: perform the second self-cleaning step in the pipe → when step S50 If the result of the comparison is that P≥ΔP is not established, or if the result of the judgment in step S70 is negative, the procedure ends and the current operating state of the air conditioning system remains unchanged.

It should be noted that, physically, the controller used to execute the above control method may be a controller specially used to execute the method of the present invention, or may be a controller of an existing air conditioning system, or may be a functional module of a general controller or functional units.

Those skilled in the art can understand that although the specific structure of the controller is not described in the above-mentioned embodiments, the controller of the above-mentioned air-conditioning system also includes some other known structures, such as a processor, a memory, etc., wherein the memory includes but is not limited to Random access memory, flash memory, read-only memory, programmable read-only memory, volatile memory, non-volatile memory, serial memory, parallel memory or registers, etc. Processors include but not limited to CPLD/FPGA, DSP, ARM processing processor, MIPS processor, etc. These well-known structures are not shown in the figures in order to unnecessarily obscure the embodiments of the present disclosure.

In addition, although the steps in the above embodiment are described in the above sequence, those skilled in the art can understand that in order to achieve the effect of this embodiment, different steps do not have to be executed in this order, which can be Simultaneous (parallel) execution or execution in reverse order, these simple variations are within the scope of the invention. For example, the step of obtaining the inlet and outlet pressures of the outdoor heat exchanger may be executed simultaneously or sequentially.

So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings, but those skilled in the art will easily understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

Claims (7)

1. A self-cleaning control method in an outdoor unit pipe of an air-conditioning system, said air-conditioning system comprising a compressor, an outdoor heat exchanger, an outdoor fan, a first throttling element, an indoor heat exchanger, an indoor fan and an oil controller, said The compressor is equipped with a liquid accumulator, and a filter screen is arranged in the liquid accumulator, and the oil control device includes a housing, an inlet pipe, an outlet pipe and an oil return pipe arranged in the housing, and the oil return pipe is connected to the oil return pipe. The inlet of the liquid reservoir is connected, and a second throttling element is arranged between the oil return pipe and the inlet of the liquid reservoir, The self-cleaning control method in the pipe of the outdoor unit includes: Obtain the inlet pressure and outlet pressure of the outdoor heat exchanger after the air conditioning system has been running for a set time; calculating the pressure difference between the inlet and outlet based on the inlet pressure and outlet pressure of the outdoor heat exchanger; Comparing the pressure difference between the inlet and outlet with the pressure difference threshold; Based on the comparison result, selectively controlling the air conditioning system to execute the self-cleaning mode in the pipe of the outdoor unit; Wherein, when the self-cleaning mode in the pipe of the outdoor unit is running, at least part of the impurities in the outdoor heat exchanger can flow into the accumulator together with the refrigerant and refrigerating machine oil; The step of "selectively controlling the air-conditioning system to execute the self-cleaning mode in the pipe of the outdoor unit based on the comparison result" further includes: When the pressure difference between the inlet and outlet is greater than or equal to the pressure difference threshold, the air conditioning system is controlled to execute the self-cleaning mode in the pipe of the outdoor unit; The step of "controlling the air-conditioning system to execute the self-cleaning mode in the outdoor unit pipe" further includes: Obtain the working mode of the air conditioning system; When the air-conditioning system operates in cooling mode, control the air-conditioning system to perform the first self-cleaning step in the pipe; When the air-conditioning system operates in a heating mode, control the air-conditioning system to perform a second self-cleaning step in the pipe; The self-cleaning step in the first tube comprises: Control the air conditioning system to adjust to the following state and continue to run for a first set time: the compressor runs at the first set frequency, the outdoor fan runs at the maximum wind speed, the indoor fan runs at the natural wind mode, all said first throttle element and said second throttle element are closed; Controlling the air conditioning system to adjust to the following state and continue to run for a second set duration: the compressor stops running, the outdoor fan stops running, the indoor fan runs in natural wind mode, and the first throttling element is closed , the second throttling element operates at the maximum opening degree. 2. The self-cleaning control method of the outdoor unit duct of the air-conditioning system according to claim 1, wherein the step of "selectively controlling the air-conditioning system to perform the self-cleaning mode of the outdoor unit duct based on the comparison result" further comprises: When the pressure difference between the inlet and outlet is less than the pressure difference threshold, the air conditioning system is controlled to maintain the current operating state. 3. The self-cleaning control method in the pipe of the outdoor unit of the air-conditioning system according to claim 1, wherein the second self-cleaning step in the pipe comprises: Controlling the air conditioning system to adjust to the following state and continue to run for a third set duration: the compressor runs at a second set frequency, the outdoor fan runs at a minimum wind speed, the indoor fan runs at a low wind speed, the the first throttling element operates at the maximum opening degree, and the second throttling element is closed; Controlling the air conditioning system to adjust to the following state and continue to run for a fourth set time period: the compressor stops running, the outdoor fan and the indoor fan both stop running, the first throttling element is closed, the second The two throttling elements operate at the maximum opening. 4. The self-cleaning control method in the pipe of the outdoor unit of the air-conditioning system according to claim 1, wherein the self-cleaning control method in the pipe of the outdoor unit further comprises: After the self-cleaning mode in the pipe of the outdoor unit is completed, the air-conditioning system is controlled to return to the state before the self-cleaning mode in the pipe of the outdoor unit is executed to continue running. 5. The self-cleaning control method in the outdoor unit pipe of the air conditioning system according to claim 1, characterized in that the following formula is used to calculate the pressure difference between the inlet and outlet: P=ABS(P _con-in - P _con-out ) Wherein, the P is the inlet and outlet pressure difference; the P _con-in is the inlet pressure of the outdoor heat exchanger; P _con-out is the outlet pressure of the outdoor heat exchanger, and the ABS means absolute value. 6. The self-cleaning control method in the pipe of an outdoor unit of an air conditioning system according to claim 1, wherein the inlet pipe communicates with the outlet of the outdoor heat exchanger, and the outlet pipe communicates with the outlet of the indoor heat exchanger The inlet is connected, and the first throttling element is arranged between the outlet pipe and the inlet of the indoor heat exchanger. 7. The self-cleaning control method in the pipe of an outdoor unit of an air conditioning system according to claim 1, wherein the first throttling element is an electronic expansion valve; and/or the second throttling element is an electronic expansion valve Or a solenoid valve with controllable opening.

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