WO2023284193A1

WO2023284193A1 - Control method for implementing self-cleaning function outside of coiled pipe of outdoor heat exchanger

Info

Publication number: WO2023284193A1
Application number: PCT/CN2021/129794
Authority: WO
Inventors: 罗荣邦; 崔俊
Original assignee: 青岛海尔空调器有限总公司; 青岛海尔空调电子有限公司; 海尔智家股份有限公司
Priority date: 2021-07-15
Filing date: 2021-11-10
Publication date: 2023-01-19
Also published as: CN113639411B; CN113639411A

Abstract

The present invention relates to the technical field of self-cleaning functions of an air conditioner, and in particular relates to a control method for implementing a self-cleaning function outside of a coiled pipe of an outdoor heat exchanger. The present application is aimed at solving the problem of it not being possible to control, according to the degree of dirtiness of an outdoor coiled pipe, a self-cleaning degree by means of an existing control method for implementing a self-cleaning function. With regards to this objective, an air conditioner in the present application comprises a recovery pipeline, a first on-off valve and a second on-off valve. The control method comprises: acquiring a running parameter of an outdoor fan; on the basis of the running parameter, determining a dust attachment degree of an outdoor heat exchanger; and on the basis of the dust attachment degree, executing a corresponding out-of-coiled-pipe self-cleaning mode, wherein the dust attachment degree comprises mild attachment, moderate attachment and severe attachment, and the out-of-coiled-pipe self-cleaning mode comprises a mild self-cleaning mode, a moderate self-cleaning mode and a deep self-cleaning mode. By means of the present application, a matched out-of-coiled-pipe self-cleaning mode can be executed on the basis of a dust attachment degree of an outdoor heat exchanger, thereby implementing a more intelligent out-of-coiled-pipe self-cleaning mode.

Description

Self-cleaning control method outside the tube of outdoor heat exchanger

technical field

The invention relates to the technical field of self-cleaning of air conditioners, in particular to a method for controlling self-cleaning outside the tube of an outdoor heat exchanger.

Background technique

Some of the current air conditioners have the self-cleaning function of the inner and outer units. Take the self-cleaning process of the outdoor heat exchanger as an example. When the self-cleaning function is executed, the frosting and defrosting operations of the outdoor coil are realized by switching between cooling and heating modes, so that when the frost layer melts, the outdoor coil will be adhered to Rinse away the dirt.

However, after the current air conditioner enters the self-cleaning mode, the cleaning method is fixed, and the degree of self-cleaning cannot be intelligently controlled according to the dirtiness of the outdoor coil. The self-cleaning time is long, which affects the normal user experience, and the self-cleaning is not thorough when the outer surface of the outdoor coil is seriously dirty.

Correspondingly, there is a need in the art for a new control method for external self-cleaning of outdoor heat exchangers to solve the above problems.

Contents of the invention

In order to solve at least one of the above-mentioned problems in the prior art, that is, in order to solve the problem that the existing self-cleaning control method cannot control the degree of self-cleaning according to the degree of dirt of the outdoor coil, the application provides an external heat exchanger for outdoor heat exchangers. The self-cleaning control method is applied to an air conditioner, and the air conditioner includes a compressor, a four-way valve, an indoor heat exchanger, a throttling device, and an outdoor heat exchanger sequentially connected through a refrigerant pipeline, and the outdoor heat exchanger is configured There is an outdoor fan, and the air conditioner also includes a recovery pipeline, a first on-off valve and a second on-off valve, the first on-off valve is arranged between the indoor heat exchanger and the throttling device On the refrigerant pipeline, one end of the recovery pipeline is arranged on the refrigerant pipeline between the first on-off valve and the throttling device, and the other end of the recovery pipeline is connected to the suction port of the compressor. connected, the second on-off valve is set on the recovery pipeline,

The control methods include:

Obtain the operating parameters of the outdoor fan;

Based on the operating parameters, judging the degree of dust adhesion of the outdoor heat exchanger;

Based on the degree of dust adhesion, perform a corresponding self-cleaning mode outside the pipe;

The degree of dust adhesion includes light adhesion, moderate adhesion and heavy adhesion, and the self-cleaning mode outside the pipe includes mild self-cleaning mode, moderate self-cleaning mode and deep self-cleaning mode;

The mild self-cleaning mode includes: controlling the air conditioner to run in heating mode; controlling the compressor to adjust to the first self-cleaning frequency; adjusting the opening of the throttling device so that the outdoor heat exchanger The coil temperature is less than or equal to the first preset temperature to realize frosting; when the coil temperature is less than or equal to the first preset temperature and lasts for a first preset time, control the air conditioner to switch to cooling mode; Controlling the opening of the second on-off valve and the opening of the throttling device to a first preset opening for a second preset duration to achieve defrosting;

The moderate self-cleaning mode includes: controlling the air conditioner to operate in a heating mode; controlling the compressor to adjust to the second self-cleaning frequency; adjusting the opening of the throttling device so that the outdoor heat exchanger The coil temperature is less than or equal to the second preset temperature to realize frosting; when the coil temperature is less than or equal to the second preset temperature and lasts for a third preset time, control the air conditioner to switch to cooling mode; Controlling the first on-off valve and the second on-off valve to close; when the first preset condition is met, controlling the second on-off valve to open and the throttling device to open to a second preset opening degree , and last for the fourth preset time to achieve defrosting;

The deep self-cleaning mode includes: controlling the air conditioner to run in heating mode; controlling the compressor to adjust to the third self-cleaning frequency; adjusting the opening of the throttling device so that the outdoor heat exchanger The coil temperature is less than or equal to the third preset temperature to realize frosting; when the coil temperature is less than or equal to the third preset temperature and lasts for a fifth preset time, control the air conditioner to switch to cooling mode; control The first on-off valve and the second on-off valve are closed; when a second preset condition is met, the second on-off valve is controlled to open, and the throttling device is opened to a third preset opening degree; After the sixth preset duration, control the second on-off valve to close; when the second preset condition is met again, control the second on-off valve to open again, and last for the seventh preset duration, to achieve defrost.

In the preferred technical solution of the above-mentioned external self-cleaning control method for outdoor heat exchangers, the mild self-cleaning mode further includes: after controlling the air conditioner to switch to cooling mode, controlling the compressor to adjust to the outdoor environment The maximum limit frequency corresponding to the temperature; and/or

After controlling the air conditioner to switch to the cooling mode, the indoor fan is controlled to stop running; and/or

The mild self-cleaning mode further includes: before adjusting the opening of the throttling device, controlling the outdoor fan to run at the lowest wind speed, and controlling the indoor fan to run at the first preset speed; and/or

The first preset opening degree is the maximum opening degree of the throttling device.

In the preferred technical solution of the above-mentioned external self-cleaning control method of the outdoor heat exchanger, the control method further includes:

After the second on-off valve is opened and the throttling device is opened to the first preset opening for the second preset duration, the mild self-cleaning mode is exited, and the air conditioner is controlled to recover to the operating state prior to entering the mild self-cleaning mode.

In the preferred technical solution of the above-mentioned external self-cleaning control method for outdoor heat exchangers, the moderate self-cleaning mode further includes: after controlling the air conditioner to switch to cooling mode, controlling the compressor to adjust to the outdoor environment The maximum limit frequency corresponding to the temperature; and/or

The moderate self-cleaning mode further includes: before adjusting the opening degree of the throttling device, controlling the outdoor fan to run at the lowest speed, and controlling the indoor fan to run at the second preset speed; and/or

The second preset opening degree is the maximum opening degree of the throttling device.

In the preferred technical solution of the above-mentioned external self-cleaning control method of the outdoor heat exchanger, the control method also includes:

After the second on-off valve is opened and the throttling device is opened to the second preset opening for the fourth preset duration, the moderate self-cleaning mode is exited, and the air conditioner is controlled to recover to the operating state before entering the intermediate self-cleaning mode.

In the preferred technical solution of the method for controlling the self-cleaning outside the pipe of the outdoor heat exchanger, the deep self-cleaning mode further includes: after controlling the air conditioner to switch to cooling mode, controlling the compressor to adjust to the outdoor ambient temperature the corresponding upper limit frequency; and/or

The deep self-cleaning mode further includes: before adjusting the opening of the throttling device, controlling the outdoor fan to run at the lowest speed, and controlling the indoor fan to run at the third preset speed; and/or

The third preset opening degree is the maximum opening degree of the throttling device.

After the second on-off valve is opened again for the seventh preset time period, the deep self-cleaning mode is exited, and the air conditioner is controlled to return to the operating state before entering the deep self-cleaning mode.

When entering the self-cleaning mode outside the tube, the outdoor anti-freezing protection function and the outdoor ambient temperature frequency limiting function are turned off.

In the preferred technical solution of the control method for self-cleaning outside the tube of the outdoor heat exchanger, the outdoor fan is a DC fan, and the operating parameters include the actual speed and voltage of the outdoor fan,

The step of "judging the degree of dust adhesion of the outdoor heat exchanger based on the operating parameters" further includes:

determining a theoretical voltage value corresponding to the actual rotational speed;

calculating an absolute value of the difference between the actual voltage value and the theoretical voltage value, and calculating a ratio between the absolute value of the difference and the theoretical voltage value;

When the ratio is greater than the first threshold and less than or equal to the second threshold, it is judged that the outdoor heat exchanger is the lightly attached;

When the ratio is greater than the second threshold and less than or equal to a third threshold, it is determined that the outdoor heat exchanger is moderately attached;

When the ratio is greater than the third threshold, it is determined that the outdoor heat exchanger is heavily attached.

In the preferred technical solution of the control method for self-cleaning outside the tube of the outdoor heat exchanger, the outdoor fan is an AC fan, and the operating parameters include the actual speed and current value of the outdoor fan,

determining a theoretical current value corresponding to the actual rotational speed;

calculating an absolute value of the difference between the actual current value and the theoretical current value, and calculating a ratio between the absolute value of the difference and the theoretical current value;

When the ratio is greater than the fourth threshold and less than or equal to the fifth threshold, it is determined that the outdoor heat exchanger is the lightly attached;

When the ratio is greater than the fifth threshold and less than or equal to the sixth threshold, it is determined that the outdoor heat exchanger is moderately attached;

When the ratio is greater than the sixth threshold, it is determined that the outdoor heat exchanger is heavily attached.

By judging the degree of dust adhesion of the outdoor heat exchanger according to the operating parameters of the outdoor fan, and then operating different self-cleaning modes outside the pipe based on the degree of dust adhesion, the control method of the present application can not only realize the self-cleaning outside the pipe of the outdoor heat exchanger, Moreover, it is also possible to implement a matching external self-cleaning mode based on the degree of dust adhesion of the outdoor heat exchanger to achieve more intelligent external self-cleaning.

Description of drawings

The method for controlling the self-cleaning outside the pipe of the outdoor heat exchanger of the present application will be described below with reference to the accompanying drawings. In the attached picture:

Fig. 1 is the system diagram of the air conditioner of the present application in heating mode;

Fig. 2 is the system diagram of the air conditioner of the present application in cooling mode;

Fig. 3 is the flowchart of the self-cleaning control method outside the tube of the outdoor heat exchanger of the present application;

Fig. 4 is a logic diagram of a possible implementation process of the method for controlling the self-cleaning outside the pipe of the outdoor heat exchanger of the present application.

List of reference signs

1. Compressor; 2. Four-way valve; 3. Outdoor heat exchanger; 4. Throttle device; 5. Indoor heat exchanger; 6. Refrigerant pipeline; 7. Recovery pipeline; 8. First on-off valve ; 9, the second on-off valve; 11, the reservoir.

detailed description

Preferred embodiments of the present application 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 application, and are not intended to limit the protection scope of the present application. For example, although the detailed steps of the method of the present application are described in detail below, those skilled in the art can combine, split and change the order of the above steps without departing from the basic principles of the present application. The scheme does not change the basic idea of the application, and therefore also falls within the scope of protection of the application.

It should be noted that in the description of this application, the terms "first", "second", "third", "fourth", "fifth", "sixth", and "seventh" are only used for describe purpose and should not be read as indicating or implying relative importance.

It should also be noted that, in the description of this application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two components. Those skilled in the art can understand the specific meanings of the above terms in this application according to specific situations.

Referring first to FIG. 1 , the structure of the air conditioner of the present application will be described. Wherein, FIG. 1 is a system diagram of the air conditioner of the present application in a heating mode.

As shown in Figure 1, in a possible implementation, the air conditioner includes a compressor 1, a four-way valve 2, an indoor heat exchanger 5, a throttling device 4, an outdoor heat exchanger 3, and a liquid reservoir 11. The heat exchanger 5 is configured with an indoor fan, and the outdoor heat exchanger 3 is configured with an outdoor fan. The exhaust port of the compressor 1 is connected with the P port of the four-way valve 2 through the refrigerant pipeline 6, and the E port of the four-way valve 2 is connected with the inlet of the indoor heat exchanger 5 through the refrigerant pipeline 6. The outlet communicates with one port of the throttling device 4 through the refrigerant pipeline 6, and the other port of the throttling device 4 communicates with the inlet of the outdoor heat exchanger 3 through the refrigerant pipeline 6, and the outlet of the outdoor heat exchanger 3 passes through the refrigerant pipeline 6 is connected with the C port of the four-way valve 2, the S port of the four-way valve 2 is connected with the inlet of the accumulator 11 through the refrigerant pipeline 6, and the outlet of the accumulator 11 is connected with the suction port of the compressor 1 through the pipeline . The throttling device 4 is preferably an electronic expansion valve, and a filter is provided in the liquid reservoir 11. The liquid reservoir 11 can store refrigerant, separate gas and liquid of refrigerant, filter oil, eliminate noise, and buffer refrigerant.

The air conditioner also includes a first on-off valve 8, a second on-off valve 9 and a recovery pipeline 7, the first on-off valve 8 and the second on-off valve 9 are preferably electromagnetic valves, and the first on-off valve 8 is Normally open valve, which is arranged on the refrigerant pipeline 6 between the throttling device 4 and the indoor heat exchanger 5, the second on-off valve 9 is a normally closed valve, which is arranged on the recovery pipeline 7, and the recovery pipeline 7 A copper tube with a smooth inner wall is used. The first end of the copper tube is set on the refrigerant pipeline 6 between the throttling device 4 and the first on-off valve 8, and the second end of the copper tube is set on the S of the four-way valve 2. On the refrigerant pipeline 6 between the interface and the inlet of the accumulator 11. Both the first on-off valve 8 and the second on-off valve 9 are communicatively connected with the controller of the air conditioner, so as to receive opening and closing signals issued by the controller. Of course, one or more of the above-mentioned on-off valves can also be replaced by electronically controlled valves such as electronic expansion valves.

The method for controlling the self-cleaning outside the tube of the outdoor heat exchanger in this embodiment will be described below in conjunction with the structure of the above-mentioned air conditioner, but those skilled in the art can understand that the specific structural composition of the air conditioner is not static, and those skilled in the art can To adjust it, for example, add or delete parts etc. on the basis of the structure of the above-mentioned air conditioner.

In the following, with reference to Fig. 1 , Fig. 2 and Fig. 3 , the method for controlling the self-cleaning outside the tube of the outdoor heat exchanger of the present application will be introduced. Wherein, FIG. 2 is a system diagram of the air conditioner of the present application in cooling mode; FIG. 3 is a flow chart of the control method of the outdoor heat exchanger for self-cleaning outside the tube of the present application.

As shown in Figure 3, in order to solve the problem that the existing self-cleaning control method cannot control the degree of self-cleaning according to the degree of dirt of the outdoor heat exchanger, the external self-cleaning control method of the outdoor heat exchanger of the present application includes:

S101. Obtain operating parameters of an outdoor fan.

In a possible implementation manner, the operating parameters of the outdoor fan include actual rotational speed, actual current value, actual voltage value, etc., and one or more of the above operating parameters of the outdoor fan are acquired during the operation of the air conditioner. Wherein, the acquisition methods of the above-mentioned operating parameters belong to conventional means in the art, and will not be repeated here.

S103. Based on the operating parameters, determine the degree of dust adhesion of the outdoor heat exchanger.

In a possible implementation manner, by reasonably calculating the above operating parameters and comparing them with preset thresholds, the range or size of the operating parameters is determined, and then the dust adhesion degree of the outdoor heat exchanger is determined. .

S105. Based on the degree of dust adhesion, execute a corresponding self-cleaning mode outside the tube.

In a possible implementation, the degree of dust adhesion in this application can be divided into light adhesion, moderate adhesion and heavy adhesion. Correspondingly, the self-cleaning mode outside the pipe includes mild self-cleaning mode, medium High self-cleaning mode and deep self-cleaning mode. That is to say, when it is judged that the degree of dust adhesion on the outdoor heat exchanger is mild, the air conditioner is controlled to perform a mild self-cleaning mode; when it is judged that the degree of dust adhesion on the outdoor heat exchanger is moderate, the air conditioner is controlled to The air conditioner performs a moderate self-cleaning mode; when it is judged that the degree of dust adhesion on the outdoor heat exchanger is heavy, the air conditioner is controlled to perform a deep self-cleaning mode.

It can be seen that by judging the degree of dust adhesion of the outdoor heat exchanger according to the operating parameters of the outdoor fan, and then operating different self-cleaning modes outside the tube based on the degree of dust adhesion, the control method of the present application can not only realize the control of the outdoor heat exchanger. External self-cleaning, and can also implement a corresponding degree of external self-cleaning mode based on the dust adhesion degree of the outdoor heat exchanger, so that the self-cleaning effect can adapt to the dust adhesion degree, and realize more intelligent external self-cleaning.

Several possible embodiments of the present application for judging the degree of dust adhesion of the outdoor heat exchanger according to the operating parameters of the air conditioner are introduced below.

Example 1

In this embodiment, the outdoor fan is a DC fan, and the operating parameters include the actual rotational speed and actual voltage value of the outdoor fan. Obtaining the operating parameters of the outdoor fan means obtaining the actual rotational speed and actual voltage value of the outdoor fan. Wherein, the way of obtaining the actual voltage value of the outdoor fan belongs to the conventional means in the field, and will not be repeated here. Wherein, the acquisition of the actual rotational speed of the outdoor fan may be achieved in the following manner:

Usually, the speed of the indoor fan is set by the user or automatically, while the speed of the outdoor fan is determined by the system according to the operating environment. In a possible implementation manner, the rotation speed of the outdoor fan is jointly determined by the frequency of the compressor and the outdoor ambient temperature. Specifically, the speed of the outdoor fan is determined by the following formula:

r＝a×f+b×Tao+c (1)

In formula (1), r is the speed of the outdoor fan, f is the operating frequency of the compressor, Tao is the outdoor ambient temperature, a is the frequency coefficient, b is the temperature coefficient, and c is a constant. a, b, and c can be determined based on the test method. The experimental process is roughly as follows: adjust the speed of the outdoor fan for each compressor operating frequency and outdoor ambient temperature, and obtain the outdoor fan speed when the outdoor heat exchanger is better. The rotational speed is taken as the optimum rotational speed of the outdoor fan at the corresponding operating frequency of the compressor and the outdoor ambient temperature. After adjusting the operating frequency of the compressor and the outdoor ambient temperature, multiple sets of test data of the optimal rotational speed are obtained, and the specific values of a, b, and c are obtained by fitting the test data.

When the air conditioner is running, the actual rotational speed of the outdoor fan is determined and adjusted in real time based on the operating frequency of the compressor and the outdoor ambient temperature. Therefore, obtaining the actual rotational speed of the outdoor fan means obtaining the current operating frequency of the compressor and the outdoor ambient temperature, and then calculating the actual rotational speed of the outdoor fan based on formula (1).

Of course, the acquisition of the actual rotational speed can also directly read the rotational speed of the outdoor fan. In this application, the actual rotational speed is acquired through a formula, which is more convenient for the following calculation and judgment process.

After obtaining the actual speed and voltage of the outdoor fan, the step of "judging the degree of dust adhesion of the outdoor heat exchanger based on the operating parameters" further includes:

Determine the theoretical voltage value corresponding to the actual speed; calculate the absolute value of the difference between the actual voltage value and the theoretical voltage value, and calculate the ratio between the absolute value of the difference and the theoretical voltage value; when the ratio is greater than the first threshold and less than or equal to When the second threshold is reached, it is judged that the outdoor heat exchanger is slightly attached; when the ratio is greater than the second threshold and less than or equal to the third threshold, it is judged that the outdoor heat exchanger is moderately attached; when the ratio is greater than the third threshold, it is judged that the outdoor heat exchanger is The heater is heavily attached.

In a possible implementation manner, the theoretical voltage value is determined based on experiments. Specifically, for different actual speeds of outdoor fans (determined based on the above formula), the input current value is fixed under the same load (such as no dust on the outdoor heat exchanger), and then the bus voltage value at each speed is recorded as The theoretical voltage value of the outdoor fan at the actual speed. During actual operation, due to the dust attached to the outdoor heat exchanger, the actual load of the outdoor fan changes. When the actual speed calculated according to the outdoor ambient temperature and the operating frequency of the compressor remains unchanged, if you still want to reach this speed, Then the air conditioner will automatically adjust the input voltage value of the outdoor fan, and the greater the load, the greater the adjusted input voltage value. Therefore, the comparison between the actual voltage value of the outdoor fan and its theoretical voltage value can be used to determine whether there is dust adhesion on the outdoor heat exchanger and the degree of dust adhesion.

For example, assuming that the theoretical voltage value corresponding to the obtained actual speed of the outdoor fan is Un, and the actual voltage value of the outdoor fan is U, first calculate the absolute value of the difference between the two △U=|U-Un| , and then calculate the ratio △U/Un of the difference △U and the theoretical voltage value, and judge the range of the ratio. In this application, the first threshold, the second threshold and the third threshold increase sequentially, wherein the first threshold is any value in 0.9-1.05, the second threshold is any value in 1.05-1.2, and the third threshold is 1.3 Any value from -1.6. In this application, the first threshold value is 1, the second threshold value is 1.1, and the third threshold value is 1.5. If △U/Un≤1, it is considered that the dust adhesion degree of the outdoor heat exchanger is not large and self-cleaning is not required; if 1 <△U/Un≤1.1, the outdoor heat exchanger is considered to be slightly attached; if 1.1<△U/Un≤1.5, the outdoor heat exchanger is considered to be moderately attached; if △U/Un>1.5, considered to be The outdoor heat exchanger is heavily attached.

Example 2

In this embodiment, the outdoor fan is an AC fan, and the operating parameters include the actual rotational speed and actual current value of the outdoor fan. Obtaining the operating parameters of the outdoor fan means obtaining the actual rotational speed and actual current value of the outdoor fan. Wherein, the manner of obtaining the actual current value of the outdoor fan belongs to conventional means in the field, and will not be repeated here. The actual rotational speed of the outdoor fan may be obtained in the same manner as in Embodiment 1, by using a formula, or directly.

After obtaining the actual rotational speed and actual current value of the outdoor fan, the step of "judging the degree of dust adhesion of the outdoor heat exchanger based on the operating parameters" further includes:

Determine the theoretical current value corresponding to the actual rotational speed; calculate the absolute value of the difference between the actual current value and the theoretical current value, and calculate the ratio between the absolute value of the difference and the theoretical current value; when the ratio is greater than the fourth threshold and less than or equal to At the fifth threshold, it is judged that the outdoor heat exchanger is slightly attached; when the ratio is greater than the fifth threshold and less than or equal to the sixth threshold, it is judged that the outdoor heat exchanger is moderately attached; when the ratio is greater than the sixth threshold, it is judged that the outdoor heat exchanger is The heater is heavily attached.

In a possible implementation manner, the theoretical current value is determined based on experiments. Specifically, for the AC fan, its voltage is a constant voltage, and for different actual speeds of the outdoor fan (determined based on the above formula), record each speed under the same load (such as no dust attached to the outdoor heat exchanger) The input current value below is taken as the theoretical current value of the outdoor fan at the actual speed. During actual operation, due to the dust attached to the outdoor heat exchanger, the actual load of the outdoor fan changes. When the actual speed calculated according to the formula remains unchanged, if the speed is still to be reached, the air conditioner will automatically adjust the outdoor fan speed. The input current value of the fan, and the greater the load, the greater the adjusted input current value. Therefore, the comparison between the actual current value of the outdoor fan and its theoretical current value can be used to determine whether there is dust adhesion on the outdoor heat exchanger and the degree of dust adhesion.

For example, assuming that the theoretical current value corresponding to the obtained actual rotational speed of the outdoor fan is In, and the actual current value of the outdoor fan is I, at this time, the absolute value of the difference between the two is first calculated △I=|I-In| , and then calculate the ratio △I/In of the difference △I and the theoretical current value, and judge the range of the ratio. In this application, the fourth threshold, the fifth threshold and the sixth threshold increase sequentially, wherein the fourth threshold is any value in 0.9-1.05, the fifth threshold is any value in 1.05-1.2, and the sixth threshold is 1.3 Any value from -1.6. In this application, the fourth threshold value is 1, the fifth threshold value is 1.1, and the sixth threshold value is 1.5. If △I/In≤1, it is considered that the dust adhesion degree of the outdoor heat exchanger is not large and self-cleaning is not required; if 1 <△I/In≤1.1, the outdoor heat exchanger is considered to be mildly attached; if 1.1<△I/In≤1.5, the outdoor heat exchanger is considered to be moderately attached; if △I/In>1.5, considered to be The outdoor heat exchanger is heavily attached.

The specific control process of each external self-cleaning mode of the present application will be introduced below.

In a possible implementation, the mild self-cleaning mode includes: controlling the air conditioner to run in the heating mode; controlling the compressor to adjust to the first self-cleaning frequency; adjusting the opening of the throttling device so that the outdoor The coil temperature of the heater is less than or equal to the first preset temperature to realize frosting on the outer surface of the coil; when the coil temperature is less than or equal to the first preset temperature and lasts for the first preset time, the air conditioner is controlled to switch to cooling mode ; Control the opening of the second on-off valve and the opening of the throttling device to the first preset opening degree, and last for the second preset duration, so as to realize the defrosting of the outer surface of the coil. specifically,

First, the air conditioner is controlled to operate in a heating mode. The switch between the operating modes of the air conditioner can be controlled by controlling the power on and off of the four-way valve. For example, when the four-way valve is powered on, the air conditioner operates in heating mode, and when the four-way valve is powered off, the air conditioner operates in cooling mode. model. In this embodiment, after entering the mild self-cleaning mode, if the air conditioner is running in the heating mode, no adjustment is required, and the air conditioner is controlled to continue running; if the air conditioner is running in the non-heating mode, the air conditioner is controlled to switch to heating Hot mode operation.

Then, control the compressor to adjust to the first self-cleaning frequency. The first self-cleaning frequency is a frequency determined in advance through experiments, for example, it may be determined based on the correspondence between the outdoor ambient temperature and the first self-cleaning frequency in Table 1 below. When the compressor operates at the first self-cleaning frequency, it facilitates the implementation of the subsequent control process.

Table 1 Comparison table between outdoor ambient temperature and first self-cleaning frequency

室外环境温度(℃)Outdoor ambient temperature (℃)	第一自清洁频率(Hz)The first self-cleaning frequency (Hz)
Tao≤-20Tao≤-20	外环温限频最高频-5Maximum frequency of outer ring temperature limit frequency -5
-20<Tao≤-10-20<Tao≤-10	外环温限频最高频-5Maximum frequency of outer ring temperature limit frequency -5
-10<Tao≤-5-10<Tao≤-5	外环温限频最高频-5Maximum frequency of outer ring temperature limit frequency -5

-5<Tao≤0-5<Tao≤0	外环温限频最高频Maximum frequency of outer ring temperature limit frequency
0<Tao≤50<Tao≤5	外环温限频最高频Maximum frequency of outer ring temperature limit frequency
5<Tao≤105<Tao≤10	外环温限频最高频+5The highest frequency of the outer ring temperature limit frequency +5
10<Tao≤1610<Tao≤16	外环温限频最高频+5The highest frequency of the outer ring temperature limit frequency +5
Tao>16Tao>16	外环温限频最高频+5The highest frequency of the outer ring temperature limit frequency +5

Next, the opening degree of the throttling device is adjusted so that the coil temperature of the outdoor heat exchanger is less than or equal to the first preset temperature, so as to achieve frosting on the outer surface of the coil. In a possible implementation, the temperature sensor can detect the coil temperature of the outdoor heat exchanger, and dynamically adjust the opening degree of the electronic expansion valve, so that the coil temperature of the outdoor heat exchanger is less than or equal to the first preset temperature. Due to the dust attached to the outer surface of the outdoor heat exchanger, after the coil temperature drops to a certain temperature and lasts for a certain period of time, frost will appear on the outer surface of the coil. The first preset temperature in this application may be set at -1°C to -10°C, and in this application, the first preset temperature may be -5°C. That is to say, the coil temperature of the outdoor heat exchanger is less than or equal to the first preset temperature as the control purpose, and by adjusting the opening degree of the electronic expansion valve (such as PID adjustment, etc.), the coil temperature of the outdoor heat exchanger is always at The state of being less than or equal to the first preset temperature.

Referring to Fig. 1, when the air conditioner is running in heating mode, the coil temperature of the outdoor heat exchanger is kept at a state of less than or equal to -5°C, and frost will form on the outer surface of the outdoor heat exchanger at this time.

Certainly, in other implementation manners, the coil temperature of the outdoor heat exchanger can also be made to be less than or equal to the first preset temperature by adjusting the opening degree of the electronic expansion valve to a fixed opening degree.

Immediately afterwards, when the coil temperature is less than or equal to the first preset temperature for a first preset time period, the air conditioner is controlled to switch to the cooling mode. The first preset duration may be any value in 5-15 minutes. Preferably, the first preset time length in this embodiment is 10 minutes. When the coil temperature is less than or equal to -5°C and lasts for 10 minutes, a layer of frost has formed on the surface of the outdoor heat exchanger. At this time, the outdoor heat can be exchanged. The device performs defrosting operation. At this time, the switch between the operation modes of the air conditioner is controlled by controlling the power on and off of the four-way valve, for example, the power off of the four-way valve is controlled, and the air conditioner operates in the cooling mode.

Finally, the second on-off valve is controlled to open, and the throttling device is opened to the first preset opening degree for a second preset duration to realize defrosting. In the present application, the first preset opening degree is the maximum opening degree of the throttling device. The second preset duration can be any value in 3min-10min, preferably 5min in this application. When the operation mode is switched to refrigeration mode, control the opening of the second on-off valve and the throttling device to the maximum opening, and keep this state for 5 minutes. At this time, as shown by the arrow in Figure 2, the high-temperature and high-pressure refrigerant discharged from the compressor flows through the outdoor heat exchanger, and the high-temperature and high-pressure refrigerant exchanges heat with the coil of the outdoor heat exchanger, melting the frost layer on the outer surface of the outdoor heat exchanger , the dust attached to the outer surface of the outdoor heat exchanger also flows away with the melted water. The high-temperature refrigerant flows back to the liquid receiver through the recovery pipeline to achieve the purpose of self-cleaning outside the tube of the outdoor heat exchanger. Control the throttling device to open to the maximum opening, so that the high-temperature and high-pressure refrigerant can pass quickly, reduce the pressure drop during the refrigerant flow process, and improve the self-cleaning effect outside the pipe.

In a possible implementation manner, the mild self-cleaning mode further includes: after the step of controlling the air conditioner to switch to cooling mode, controlling the compressor to adjust to the highest limit frequency corresponding to the outdoor ambient temperature. Usually, the operating frequency of the compressor is affected by the outdoor ambient temperature and cannot be increased without limit, otherwise the phenomenon of high temperature protection shutdown of the compressor will easily occur, which will have a negative impact on the life of the compressor. Therefore, the compressors are all equipped with a protection mechanism. Under different outdoor ambient temperatures, the corresponding maximum frequency limit is set. In this application, after the air conditioner is converted to cooling mode, the rating of the compressor is adjusted to the current outdoor ambient temperature. Under this frequency limit, the compressor can increase the temperature and pressure of the refrigerant in the shortest time, thereby improving the self-cleaning effect. Wherein, the manner of obtaining the outdoor ambient temperature is a conventional means in the field, and will not be repeated here.

In a possible implementation manner, the mild self-cleaning mode further includes: before adjusting the opening degree of the throttling device, controlling the outdoor fan to run at the lowest speed, and controlling the indoor fan to run at the first preset speed. Specifically, in the mild self-cleaning mode, before adjusting the opening of the throttling device, the outdoor fan is controlled to run at the lowest speed to reduce the heat exchange effect between the outdoor heat exchanger and the air, thereby speeding up the cooling of the outdoor disk. The temperature reduction speed of the tube improves the self-cleaning efficiency outside the tube. The first preset speed in this application can be the lowest speed in the speed of the indoor fan, such as 400r/min-700r/min, this application can be 500r/min, because the dust adhesion of the outdoor heat exchanger is not serious , and the air conditioner is adjusting the indoor ambient temperature before entering the mild self-cleaning mode, so on the basis of ensuring the self-cleaning effect, by controlling the outdoor fan to run at the lowest speed, and the indoor fan to run at the first preset speed , to ensure a certain degree of indoor comfort.

In a possible implementation manner, after the air conditioner is controlled to switch to cooling mode, the indoor fan is controlled to stop running. Specifically, when the cooling mode is running, the outlet air temperature of the indoor unit gradually decreases, which will bring bad user experience to the user. At this time, the fan in the control room stops running after running for 30 seconds, which can prevent the temperature of the outlet air from being too low and affect the user experience. Of course, those skilled in the art can adjust the above 30s, such as adjusting to any value in 10s-1min.

In a possible implementation manner, the method further includes: when entering the mild self-cleaning mode, turning off the outdoor antifreeze protection function and the outdoor ambient temperature frequency limiting function. Since the coil temperature of the outdoor heat exchanger needs to be lowered to a lower value, in order to reach this condition as soon as possible, the compressor needs to run at high frequency. frequency function to ensure the smooth execution of the method. However, other protection functions of the air conditioner are turned on as usual, such as compressor exhaust protection and current overload protection, etc., to prevent adverse effects on the life of the air conditioner.

Of course, the specific control process of the mild self-cleaning mode is not unique, and those skilled in the art can adjust the control method. For example, on the premise that the coil temperature of the outdoor heat exchanger can be kept at or below the first preset temperature, the operation frequency of the compressor, the opening degree of the electronic expansion valve, the speed of the indoor fan and the One or more of the rotational speeds of the outdoor fans are omitted. For another example, after the air conditioner is controlled to switch to cooling mode, no adjustments may be made to the throttling device.

In a possible implementation, the method further includes: exiting the mild self-cleaning mode and controlling the air conditioner to return to The operating state before entering the light self-cleaning mode. When the second on-off valve is opened and the throttling device is opened to the maximum opening for 5 minutes, the high-temperature and high-pressure refrigerant has circulated several times, which is enough to complete the defrosting operation. Therefore, when the second on-off valve is opened and the throttling device is opened to When the maximum opening lasts for 5 minutes, the mild self-cleaning mode can be exited.

Specifically, the step of exiting the mild self-cleaning mode further includes: controlling the air conditioner to return to the operating mode before entering the mild self-cleaning mode, controlling the compressor to return to the frequency before entering the mild self-cleaning mode, controlling the indoor fan to turn on and The air deflector of the indoor unit supplies air upwards, controls the throttling device to open to the maximum opening, and controls the second on-off valve to close. After the light self-cleaning mode is completed, the air conditioner needs to return to the operating mode before entering the light self-cleaning mode, so as to continue to adjust the indoor temperature. The following takes the heating mode of the air conditioner before entering the mild self-cleaning mode as an example. After the light self-cleaning mode is executed, it needs to switch back to the heating mode. At this time, control the four-way valve to restore the heating mode, control the frequency of the compressor to return from the maximum limit value to the frequency before entering the mild self-cleaning mode, control the indoor fan to turn on and the air deflector of the indoor unit to send air upward, and control the electronic The expansion valve is opened to the maximum opening degree, and the second on-off valve is controlled to be closed, so that the refrigerant flows in the normal heating mode flow direction. Among them, the indoor fan is turned on and the air deflector of the indoor unit blows air upwards, so as to prevent the user from having a bad user experience when the temperature of the outdoor heat exchanger coil is too low when the air conditioner just switches to the heating mode. Among them, the throttling device is opened to the maximum opening, because the refrigerant circulates between the compressor and the outdoor heat exchanger when the mild self-cleaning mode is running, resulting in the lack of refrigerant in the indoor heat exchanger, so the throttling device is opened to the maximum opening , so that the refrigerant quickly fills the indoor heat exchanger, so as to realize the normal circulation of the refrigerant as soon as possible.

Correspondingly, after the fan in the control room is turned on and the wind deflector is blowing air upwards for the first duration, the fan in the control room and the wind deflector return to the operating state before entering the mild self-cleaning mode. Wherein, the first duration can be any value from 20s to 1min. In this application, it is preferably 30s. When the indoor fan is turned on and the air guide plate blows air upwards for 30s, the temperature of the coil of the outdoor heat exchanger has dropped to the same level as that of heating. At this time, control the indoor fan and the wind deflector to return to the operating mode before entering the mild self-cleaning mode to meet the heating demand of the user.

Correspondingly, after the throttling device is controlled to open to the maximum opening for a second duration, the throttling device is controlled to return to the opening before entering the mild self-cleaning mode. Among them, the second duration can be any value within 1min-5min, and it is preferably 3min in this application. When the electronic expansion valve maintains the maximum opening and runs for 3min, the refrigerant circulation has tended to be stable. The opening degree before the mild self-cleaning mode, so that the air conditioner can fully restore the heating parameters before entering the mild self-cleaning mode and continue to run.

Of course, the way to exit the mild self-cleaning mode is not limited to the above one, and those skilled in the art can freely choose a specific control mode on the premise that the air conditioner can be restored to the operating state before entering the mild self-cleaning mode. This choice does not depart from the principles of the present application. For example, the outdoor fan can be controlled to return to the operating state before entering the mild self-cleaning mode; another example, the indoor fan can be controlled to be turned off first, and then the temperature of the coil of the outdoor heat exchanger has dropped to a level suitable for the heating mode. After the temperature is reached, the indoor fan is controlled to start running. For another example, it is also possible to control the various components of the air conditioner to directly return to the operating parameters before entering the mild self-cleaning mode.

In a possible implementation, the moderate self-cleaning mode includes: controlling the air conditioner to run in the heating mode; controlling the compressor to adjust to the second self-cleaning frequency; adjusting the opening degree of the throttling device so that the disc of the outdoor heat exchanger The tube temperature is less than or equal to the second preset temperature to realize frosting; when the coil temperature is less than or equal to the second preset temperature and lasts for the third preset time, control the air conditioner to switch to cooling mode; control the first on-off valve and the second The two-way on-off valve is closed; when the first preset condition is met, the second on-off valve is controlled to open, and the throttling device is opened to the second preset opening degree, and lasts for a fourth preset time period to realize defrosting. specifically,

First, the air conditioner is controlled to operate in a heating mode. Similar to the above mild self-cleaning mode, switching between operating modes of the air conditioner can be controlled by controlling the four-way valve on and off. In this embodiment, after entering the moderate self-cleaning mode, if the air conditioner is running in the heating mode, no adjustment is required, and the air conditioner is controlled to continue running; if the air conditioner is in the non-heating mode, the air conditioner is controlled to switch to the heating mode Hot mode operation.

Then, control the compressor to adjust to the second self-cleaning frequency. The second self-cleaning frequency is a frequency determined through experiments in advance, and its determination method can refer to the above-mentioned Table 1, which will not be repeated here. When the compressor operates at the second self-cleaning frequency, it facilitates the implementation of the subsequent control process.

Next, the opening degree of the throttling device is adjusted so that the coil temperature of the outdoor heat exchanger is less than or equal to the second preset temperature, so as to achieve frosting on the outer surface of the coil. Preferably, the second preset temperature is lower than the first preset temperature. In this application, the second preset temperature may be -10°C. That is to say, the coil temperature of the outdoor heat exchanger is less than or equal to the second preset temperature as the control purpose, and by adjusting the opening degree of the electronic expansion valve (such as PID adjustment, etc.), the coil temperature of the outdoor heat exchanger is always at The state of being less than or equal to the second preset temperature. In this way, the outer surface of the coil can be frosted faster than in the mild self-cleaning mode, and the thickness of the frost layer is thicker.

Referring to Figure 1, when the air conditioner is running in the heating mode, the coil temperature of the outdoor heat exchanger is kept at a state of less than or equal to -10°C. At this time, frost forms on the outer surface of the outdoor heat exchanger and the frost layer adheres to the outside The outer surface of the coil of the heat exchanger.

Certainly, in other implementation manners, the coil temperature of the outdoor heat exchanger can also be made to be less than or equal to the second preset temperature by adjusting the opening degree of the electronic expansion valve to a fixed opening degree.

Immediately afterwards, when the coil temperature is less than or equal to the second preset temperature for a third preset time period, the air conditioner is controlled to switch to the cooling mode. The third preset duration may be any value in 5-15 minutes. Preferably, the third preset time length in this embodiment is 10 minutes. When the coil temperature is less than or equal to -10°C and lasts for 10 minutes, a layer of frost has formed on the surface of the outdoor heat exchanger. At this time, the outdoor heat can be exchanged. The device performs defrosting operation. At this time, the switch between the operation modes of the air conditioner is controlled by controlling the power on and off of the four-way valve, for example, the power off of the four-way valve is controlled, and the air conditioner operates in the cooling mode.

Next, after the air conditioner is converted into cooling mode, the first on-off valve and the second on-off valve are controlled to be closed. After the first on-off valve and the second on-off valve are closed, the refrigerant pipeline and the recovery pipeline between the throttling device and the indoor heat exchanger are throttled. At this time, as shown in Figure 2, the indoor heat exchanger and the refrigerant in the refrigerant pipeline is discharged by the compressor and accumulated in the outdoor heat exchanger.

Finally, it is judged whether the first preset condition is met, and when the first preset condition is met, the second on-off valve is controlled to open, and the throttling device is opened to the second preset opening degree for a fourth preset duration. In the present application, the first preset condition is that the discharge temperature of the compressor is greater than or equal to the discharge temperature threshold and lasts for an eighth preset duration. Wherein, the eighth preset duration is preferably any value in 3s-10s, and 5s is used in this application. The exhaust gas temperature can be acquired continuously or at intervals, such as every 1s-5s. In the present application, the second preset opening degree is the maximum opening degree of the throttling device, and the throttling device is controlled to open to the maximum opening degree, so that the high-temperature and high-pressure refrigerant can pass quickly. The fourth preset duration can be any value in 3min-10min, preferably 5min in this application. When the discharge temperature is greater than or equal to the discharge temperature threshold and lasts for the eighth preset time, the refrigerant has accumulated in the outdoor heat exchanger and the pressure of the discharge port of the compressor rises to a higher value at this time, which meets the conditions and can be carried out Defrost operation. Therefore, when the above conditions are satisfied, open the second on-off valve, open the throttling device to the maximum opening, and keep this state for 5 minutes to realize the defrosting of the high-temperature and high-pressure refrigerant and ensure the speed and effect of defrosting. At this time, as shown by the arrow in Figure 2, the high-temperature and high-pressure refrigerant discharged from the compressor flows through the outdoor heat exchanger, and the high-temperature and high-pressure refrigerant exchanges heat with the coil of the outdoor heat exchanger, melting the frost layer on the outer surface of the outdoor heat exchanger , the dust attached to the outer surface of the outdoor heat exchanger also flows away with the melted water. The high-temperature refrigerant flows back to the liquid receiver through the recovery pipeline to achieve the purpose of self-cleaning outside the tube of the outdoor heat exchanger.

Although the exhaust gas temperature threshold is not illustrated in the above embodiments, this does not mean that the technical solution of the present application cannot be implemented. On the contrary, those skilled in the art can test and determine the exhaust gas temperature threshold based on the principles disclosed in this application, as long as the threshold is set so that the outdoor heat exchanger has a better defrosting effect when the second on-off valve is opened. The effect is enough. In addition, the first preset condition is not limited to the above-mentioned discharge temperature being greater than or equal to the preset discharge temperature threshold. On the premise that the pressure/temperature state at the compressor discharge port can be judged, those skilled in the art can use other parameters Replace it. For example, the comparison between the discharge pressure of the compressor and the preset discharge pressure may be selected as the first preset condition, or the comparison between the suction pressure of the compressor and the preset suction pressure threshold may be used as the first preset condition.

In a possible implementation manner, the moderate self-cleaning mode further includes: after the step of controlling the air conditioner to switch to cooling mode, controlling the compressor to adjust to the highest limit frequency corresponding to the outdoor ambient temperature. Usually, the operating frequency of the compressor is affected by the outdoor ambient temperature and cannot be increased indefinitely, otherwise the phenomenon of high temperature protection shutdown of the compressor will easily occur, which will have a negative impact on the life of the compressor. Therefore, the compressors are all equipped with a protection mechanism. Under different outdoor ambient temperatures, the corresponding maximum frequency limit is set. In this application, after the air conditioner is switched to cooling mode, the rating of the compressor is adjusted to the current outdoor ambient temperature. Under this frequency limit, the compressor can increase the temperature and pressure of the refrigerant in the shortest time, thereby improving the self-cleaning effect. Wherein, the manner of obtaining the outdoor ambient temperature is a conventional means in the field, and will not be repeated here.

In a possible implementation manner, the moderate self-cleaning mode further includes, before adjusting the opening degree of the throttling device, controlling the outdoor fan to run at the lowest speed, and controlling the indoor fan to run at the second preset speed. Specifically, in the moderate self-cleaning mode, before adjusting the opening degree of the throttling device, the outdoor fan is controlled to run at the lowest speed to reduce the heat exchange effect between the outdoor heat exchanger and the air, so that the outdoor disk can be accelerated. The temperature reduction speed of the tube improves the self-cleaning efficiency outside the tube. In this application, the second preset speed can be the highest speed of the indoor fan. Since the dust adhesion of the outdoor heat exchanger is relatively serious, before adjusting the opening of the throttling device, the indoor fan can be controlled to run at the highest speed, which can improve The heat exchange effect between the refrigerant in the indoor heat exchanger and the environment, thereby reducing the temperature and pressure of the refrigerant, improving the evaporation effect of the refrigerant in the outdoor heat exchanger, and reducing the outdoor coil to the second preset temperature at a faster speed. Set temperature.

In a possible implementation manner, the moderate self-cleaning mode further includes: controlling the indoor fan to stop running after controlling the air conditioner to switch to the cooling mode. Specifically, when the cooling mode is running, the outlet air temperature of the indoor unit will gradually decrease, which will bring a bad experience to the user. At this time, the fan in the control room stops running after running for 30 seconds, which can prevent the temperature of the outlet air from being too low and affect the user experience. Of course, those skilled in the art can adjust the above 30s, such as adjusting to any value in 10s-1min.

In a possible implementation, the method further includes: when entering the moderate self-cleaning mode, turning off the outdoor antifreeze protection function and the outdoor ambient temperature frequency limiting function, but turning on other protection functions of the air conditioner as usual. The purpose and implementation of this step are the same as those in the light cleaning mode, so details will not be repeated here.

Of course, the specific control process of the moderate self-cleaning mode is not unique, and those skilled in the art can adjust the control method. For example, on the premise that the coil temperature of the outdoor heat exchanger can be kept less than or equal to the second preset temperature, the operation frequency of the compressor, the opening degree of the electronic expansion valve, the speed of the indoor fan and the One or more of the rotational speeds of the outdoor fans are omitted. For another example, after the air conditioner is controlled to switch to cooling mode, no adjustments may be made to the throttling device.

In a possible implementation, the method further includes: exiting the moderate self-cleaning mode and controlling the air conditioner to return to Operating state prior to entering moderate self-cleaning mode. When the second on-off valve is opened and the throttling device is opened to the maximum for 5 minutes, the high-temperature and high-pressure refrigerant has circulated for many times, which is enough to produce defrosting operation, so when the second on-off valve is opened, the throttle device is opened to the maximum and When it lasts for 5 minutes, you can exit the moderate self-cleaning mode.

In the present application, the purpose of exiting the moderate self-cleaning mode can be achieved by using the same control method as that for exiting the mild self-cleaning mode described above, which will not be repeated here.

Of course, the way of exiting the moderate self-cleaning mode is not limited to the same method as exiting the mild self-cleaning mode. On the premise that the air conditioner can be restored to the operating state before entering the moderate self-cleaning mode, the technology in the art Personnel can freely choose a specific control mode, and this choice does not deviate from the principle of the present application. For example, the outdoor fan can be controlled to return to the operating state before entering the moderate self-cleaning mode; another example, the indoor fan can be controlled to be turned off first, and then the temperature of the coil of the indoor heat exchanger rises to a temperature suitable for the heating mode. After the temperature is reached, the indoor fan is controlled to start running. For another example, various components of the air conditioner can be controlled to directly restore to the operating parameters before entering the moderate self-cleaning mode.

In a possible implementation, the deep self-cleaning mode includes: controlling the air conditioner to run in heating mode; controlling the compressor to adjust to the third self-cleaning frequency; adjusting the opening degree of the throttling device so that the coil of the outdoor heat exchanger The temperature is less than or equal to the third preset temperature to realize frosting; when the coil temperature is less than or equal to the third preset temperature and lasts for the fifth preset time, control the air conditioner to switch to cooling mode; control the first on-off valve and the second The on-off valve is closed; when the second preset condition is met, the second on-off valve is controlled to open, and the throttling device is opened to the third preset opening degree; after the sixth preset duration, the second on-off valve is controlled to be closed ; When the second preset condition is met again, control the second on-off valve to open again, and last for the seventh preset time to realize defrosting. specifically,

More preferably, the above operating parameters of deep self-cleaning in the present application can be set the same as the corresponding parameters in the moderate self-cleaning mode, that is, the third self-cleaning frequency, the third preset temperature, the fifth preset duration, the first Parameters such as the second preset condition and the sixth preset duration are the same as the moderate self-cleaning. The difference between the control process of the deep self-cleaning mode and the moderate self-cleaning mode is:

After the second preset condition is met, the second on-off valve is controlled to open, the throttle device is opened to the maximum opening and lasts for the sixth preset time, the deep self-cleaning mode is not immediately exited, but the second on-off valve is controlled Close it again, and then continue to judge whether the second preset condition is met, and if it is met, open the second on-off valve again to defrost the outdoor heat exchanger for the seventh preset time. Wherein, the seventh preset duration can be any value in 1-5 minutes in this application, and 3 minutes is selected in this application. By controlling the first on-off valve to close and open again, the defrosting of the outdoor heat exchanger is more thorough, and the self-cleaning effect is more in line with the current degree of dust adhesion of the outdoor heat exchanger.

Of course, it is only a preferred embodiment that the control parameters of deep self-cleaning are the same as those of moderate self-cleaning. In other embodiments, those skilled in the art can also adjust the control parameters of deep self-cleaning to achieve better Good deep self-cleaning effect. For example, the deep self-cleaning mode can only run for one cycle, and the third preset temperature can be further lowered than the second preset temperature, and the fifth or sixth preset duration can be compared with the third or fourth preset temperature. Set the duration to increase, etc.

In a possible implementation manner, the deep self-cleaning mode further includes: after the step of controlling the air conditioner to switch to cooling mode, controlling the compressor to adjust to the highest limit frequency corresponding to the outdoor ambient temperature.

In a possible implementation manner, the deep self-cleaning mode further includes: before adjusting the opening of the throttling device, controlling the outdoor fan to run at the lowest speed, and controlling the indoor fan to run at the third preset speed. Specifically, in the deep self-cleaning mode, before adjusting the opening of the throttling device, the outdoor fan is first controlled to run at the lowest speed to reduce the heat exchange effect between the outdoor heat exchanger and the air, thereby speeding up the cooling of the outdoor coil. The lowering speed of the temperature improves the self-cleaning efficiency in the tube. In this application, the third preset speed can be the highest speed of the indoor fan. Since the outdoor heat exchanger is more dirty and clogged, before adjusting the opening of the throttling device, the indoor fan can be controlled to run at the highest speed, which can improve The heat exchange effect between the refrigerant in the indoor heat exchanger and the environment, thereby reducing the temperature and pressure of the refrigerant, improving the evaporation effect of the refrigerant in the outdoor heat exchanger, and reducing the outdoor coil to the third preset temperature at a faster speed .

In a possible implementation manner, the deep self-cleaning mode further includes: controlling the indoor fan to stop running after the air conditioner is controlled to switch to the cooling mode. Specifically, when the cooling mode is running, the outlet air temperature of the indoor unit gradually decreases, which will bring bad user experience to the user. At this time, the fan in the control room stops running after running for 30 seconds, which can prevent the temperature of the outlet air from being too low and affect the user experience. Of course, those skilled in the art can adjust the above 30s, such as adjusting to any value in 10s-1min.

In a possible implementation, the method further includes: when entering the deep self-cleaning mode, turning off the outdoor antifreeze protection function and the outdoor ambient temperature frequency limiting function, but turning on other protection functions of the air conditioner as usual. The purpose and implementation of this step are the same as those in the light cleaning mode, so details will not be repeated here.

Of course, the specific control process of the deep self-cleaning mode is not unique, and those skilled in the art can adjust the control method. For example, on the premise that the coil temperature of the outdoor heat exchanger can be kept at or below the third preset temperature, the operation frequency of the compressor, the opening degree of the electronic expansion valve, the speed of the indoor fan and the One or more of the rotational speeds of the outdoor fans are omitted. For another example, after the air conditioner is controlled to switch to cooling mode, no adjustments may be made to the throttling device.

In a possible implementation, the method further includes: exiting the deep self-cleaning mode after the second on-off valve is opened again for a seventh preset period of time, and controlling the air conditioner to return to the operating state before entering the deep self-cleaning mode . When the second on-off valve is opened for the second time and lasts for the seventh preset time, it is enough to produce a better defrosting effect, so when the second on-off valve is opened again and lasts for the seventh preset time, you can exit the deep automatic cleaning mode.

In the present application, the purpose of exiting the deep self-cleaning mode can be realized by using the same control method as exiting the light self-cleaning mode described above, which will not be repeated here.

Of course, the method of exiting the deep self-cleaning mode is not limited to the same method as exiting the mild self-cleaning mode. On the premise that the air conditioner can be restored to the operating state before entering the deep self-cleaning mode, those skilled in the art can The specific control mode is free to choose, and this choice does not deviate from the principle of the present application. For example, the outdoor fan can be controlled to return to the operating state before entering the deep self-cleaning mode; another example, the indoor fan can be controlled to be turned off first, and then the coil temperature of the indoor heat exchanger can be obtained to rise to a temperature suitable for the heating mode After that, control the indoor fan to start running. For another example, it is possible to control the various components of the air conditioner to directly return to the operating parameters before entering the deep self-cleaning mode.

In general, the three external self-cleaning modes of this application, by controlling the air conditioner to run the heating mode first, and adjusting the opening of the throttling device to make frost on the outer surface of the outdoor heat exchanger, and then control the air conditioner Switch to refrigeration mode, and open the second on-off valve or first close the first on-off valve and the second on-off valve and open the second on-off valve and throttling device when the preset conditions are met, using high-temperature and high-pressure refrigerant to communicate with the outdoor The coil of the heat exchanger conducts heat exchange for high-temperature defrosting, so that the dust attached to the outer surface of the coil falls together with the melted water after the frost layer melts, and the refrigerant is directly returned to the inside of the liquid receiver through the recovery pipeline to realize Self-cleaning outside the tubes of outdoor heat exchangers. In addition, the cleaning effect of the three external self-cleaning modes from mild, moderate to deep self-cleaning mode is enhanced sequentially, which can make the cleaning effect match the dust adhesion effect and realize the intelligent self-cleaning of the outdoor heat exchanger.

In addition, by setting the recovery pipeline in the air conditioner, the application can use the recovery pipeline to shorten the circulation path of the refrigerant during the self-cleaning process outside the tube of the outdoor heat exchanger, and realize the high-efficiency of the high-temperature and high-pressure refrigerant and the outdoor heat exchanger. Heat exchange reduces the pressure drop along the way and improves the self-cleaning effect outside the tube.

A possible implementation process of the present application will be described below with reference to FIG. 4 . Wherein, FIG. 4 is a logic diagram of a possible implementation process of the method for controlling the self-cleaning outside the pipe of the outdoor heat exchanger of the present application.

As shown in Figure 4, the air conditioner is turned on for heating and running, and then performs the following operations:

First, step S201 is executed to obtain the actual voltage value U of the outdoor fan, the operating frequency f of the compressor, and the outdoor ambient temperature Tao.

Next, step S203 is executed to calculate the actual rotational speed r of the outdoor fan based on the formula r=a×f+b×Tao+c.

Next, step S205 is executed, based on the actual rotational speed r, the corresponding theoretical voltage value Un is determined, and ΔU=|U-Un| is calculated.

Next, step S207 is executed to determine whether △U/Un≤1 is true, and if true, end the operation; otherwise, when not true, execute step S209, where △U=|U-Un|, Un is the actual speed of the outdoor fan The corresponding theoretical voltage value, U is the actual voltage value of the outdoor fan.

S209 , judging whether 1<ΔU/Un≦1.1 is true; if true, execute step S213 ; otherwise, if not, execute step S211 .

S211, judging whether 1.1<ΔU/Un≤1.5 holds true; if true, execute step S215; otherwise, if not, execute step S217.

S213, executing a mild self-cleaning mode.

S215, executing a moderate self-cleaning mode.

S217, executing a deep self-cleaning mode.

Those skilled in the art can understand that the above air conditioner also includes some other known structures, such as a processor, a controller, a memory, etc., wherein the memory includes but 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 processors, MIPS processors, etc. These well-known structures are not shown in the figures in order to unnecessarily obscure the embodiments of the present disclosure.

In the above embodiment, although the various steps are described according to 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, and they can be performed at the same time ( Parallel) execution or execution in reversed order, these simple changes are all within the protection scope of the present application.

So far, the technical solutions of the present application have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principle of the present application, 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 application.

Claims

A self-cleaning control method outside the tube of an outdoor heat exchanger, which is applied to an air conditioner, and is characterized in that the air conditioner includes a compressor, a four-way valve, an indoor heat exchanger, and a throttling device sequentially connected through a refrigerant pipeline . An outdoor heat exchanger, the outdoor heat exchanger is equipped with an outdoor fan, the air conditioner also includes a recovery pipeline, a first on-off valve and a second on-off valve, the first on-off valve is arranged on the On the refrigerant pipeline between the indoor heat exchanger and the throttling device, one end of the recovery pipeline is arranged on the refrigerant pipeline between the first on-off valve and the throttling device, and the recovery pipeline The other end of the pipeline communicates with the suction port of the compressor, and the second on-off valve is arranged on the recovery pipeline,

The control methods include:

Obtain the operating parameters of the outdoor fan;

Based on the operating parameters, judging the degree of dust adhesion of the outdoor heat exchanger;

Based on the degree of dust adhesion, perform a corresponding self-cleaning mode outside the pipe;

The degree of dust adhesion includes light adhesion, moderate adhesion and heavy adhesion, and the self-cleaning mode outside the pipe includes mild self-cleaning mode, moderate self-cleaning mode and deep self-cleaning mode;

The mild self-cleaning mode includes: controlling the air conditioner to run in heating mode; controlling the compressor to adjust to the first self-cleaning frequency; adjusting the opening of the throttling device so that the outdoor heat exchanger The coil temperature is less than or equal to the first preset temperature to realize frosting; when the coil temperature is less than or equal to the first preset temperature and lasts for a first preset time, control the air conditioner to switch to cooling mode; Controlling the opening of the second on-off valve and the opening of the throttling device to a first preset opening for a second preset duration to achieve defrosting;

The moderate self-cleaning mode includes: controlling the air conditioner to operate in a heating mode; controlling the compressor to adjust to the second self-cleaning frequency; adjusting the opening of the throttling device so that the outdoor heat exchanger The coil temperature is less than or equal to the second preset temperature to realize frosting; when the coil temperature is less than or equal to the second preset temperature and lasts for a third preset time, control the air conditioner to switch to cooling mode; Controlling the first on-off valve and the second on-off valve to close; when the first preset condition is met, controlling the second on-off valve to open and the throttling device to open to a second preset opening degree , and last for the fourth preset time to achieve defrosting;

The deep self-cleaning mode includes: controlling the air conditioner to run in heating mode; controlling the compressor to adjust to the third self-cleaning frequency; adjusting the opening of the throttling device so that the outdoor heat exchanger The coil temperature is less than or equal to the third preset temperature to realize frosting; when the coil temperature is less than or equal to the third preset temperature and lasts for a fifth preset time, control the air conditioner to switch to cooling mode; control The first on-off valve and the second on-off valve are closed; when a second preset condition is met, the second on-off valve is controlled to open, and the throttling device is opened to a third preset opening degree; After the sixth preset duration, control the second on-off valve to close; when the second preset condition is met again, control the second on-off valve to open again, and last for the seventh preset duration, to achieve defrost.
The external self-cleaning control method of the outdoor heat exchanger according to claim 1, characterized in that:

The mild self-cleaning mode further includes: after controlling the air conditioner to switch to cooling mode, controlling the compressor to adjust to the highest limit frequency corresponding to the outdoor ambient temperature; and/or

After controlling the air conditioner to switch to the cooling mode, the indoor fan is controlled to stop running; and/or

The mild self-cleaning mode further includes: before adjusting the opening of the throttling device, controlling the outdoor fan to run at the lowest wind speed, and controlling the indoor fan to run at the first preset speed; and/or

The first preset opening degree is the maximum opening degree of the throttling device.
The method for controlling self-cleaning outside the pipe of an outdoor heat exchanger according to claim 2, wherein the control method further comprises:

After the second on-off valve is opened and the throttling device is opened to the first preset opening for the second preset duration, the mild self-cleaning mode is exited, and the air conditioner is controlled to recover to the operating state prior to entering the mild self-cleaning mode.
The external self-cleaning control method of the outdoor heat exchanger according to claim 1, characterized in that:

The moderate self-cleaning mode further includes: after controlling the air conditioner to switch to cooling mode, controlling the compressor to adjust to the highest limit frequency corresponding to the outdoor ambient temperature; and/or

After controlling the air conditioner to switch to the cooling mode, the indoor fan is controlled to stop running; and/or

The moderate self-cleaning mode further includes: before adjusting the opening degree of the throttling device, controlling the outdoor fan to run at the lowest speed, and controlling the indoor fan to run at the second preset speed; and/or

The second preset opening degree is the maximum opening degree of the throttling device.
The method for controlling the self-cleaning outside the tube of an outdoor heat exchanger according to claim 4, wherein the control method further comprises:

After the second on-off valve is opened and the throttling device is opened to the second preset opening for the fourth preset duration, the moderate self-cleaning mode is exited, and the air conditioner is controlled to recover to the operating state before entering the intermediate self-cleaning mode.
The external self-cleaning control method of the outdoor heat exchanger according to claim 1, characterized in that:

The deep self-cleaning mode further includes: after controlling the air conditioner to switch to cooling mode, controlling the compressor to adjust to the highest limit frequency corresponding to the outdoor ambient temperature; and/or

After controlling the air conditioner to switch to the cooling mode, the indoor fan is controlled to stop running; and/or

The deep self-cleaning mode further includes: before adjusting the opening of the throttling device, controlling the outdoor fan to run at the lowest speed, and controlling the indoor fan to run at the third preset speed; and/or

The third preset opening degree is the maximum opening degree of the throttling device.
The method for controlling the self-cleaning outside the tube of an outdoor heat exchanger according to claim 6, wherein the control method further comprises:

After the second on-off valve is opened again for the seventh preset time period, the deep self-cleaning mode is exited, and the air conditioner is controlled to return to the operating state before entering the deep self-cleaning mode.
The method for controlling self-cleaning outside the pipe of an outdoor heat exchanger according to claim 1, wherein the control method further comprises:

When entering the self-cleaning mode outside the tube, the outdoor anti-freezing protection function and the outdoor ambient temperature frequency limiting function are turned off.
The method for controlling self-cleaning outside the tube of an outdoor heat exchanger according to claim 1, wherein the outdoor fan is a DC fan, and the operating parameters include the actual speed and voltage of the outdoor fan,

The step of "judging the degree of dust adhesion of the outdoor heat exchanger based on the operating parameters" further includes:

determining a theoretical voltage value corresponding to the actual rotational speed;

calculating an absolute value of the difference between the actual voltage value and the theoretical voltage value, and calculating a ratio between the absolute value of the difference and the theoretical voltage value;

When the ratio is greater than the first threshold and less than or equal to the second threshold, it is judged that the outdoor heat exchanger is the lightly attached;

When the ratio is greater than the second threshold and less than or equal to a third threshold, it is determined that the outdoor heat exchanger is moderately attached;

When the ratio is greater than the third threshold, it is determined that the outdoor heat exchanger is heavily attached.
The method for controlling self-cleaning outside the tube of an outdoor heat exchanger according to claim 1, wherein the outdoor fan is an AC fan, and the operating parameters include the actual speed and current value of the outdoor fan,

The step of "judging the degree of dust adhesion of the outdoor heat exchanger based on the operating parameters" further includes:

determining a theoretical current value corresponding to the actual rotational speed;

calculating an absolute value of the difference between the actual current value and the theoretical current value, and calculating a ratio between the absolute value of the difference and the theoretical current value;

When the ratio is greater than the fourth threshold and less than or equal to the fifth threshold, it is determined that the outdoor heat exchanger is the lightly attached;

When the ratio is greater than the fifth threshold and less than or equal to the sixth threshold, it is determined that the outdoor heat exchanger is moderately attached;

When the ratio is greater than the sixth threshold, it is determined that the outdoor heat exchanger is heavily attached.