Air conditioner and self-cleaning control method thereof

Abstract

The present invention discloses an air conditioner and a self-cleaning control method for the air conditioner. The air conditioner includes: a filter screen disposed on the indoor side for filtering the air input from the outdoor side into the indoor side; a controller configured to: determine the current operating condition of the air conditioner; obtain the inlet temperature and the outlet temperature of the evaporator, as well as obtain the air outlet speed of the air conditioner, and obtain the air outlet temperature and the air inlet temperature of the air conditioner; obtain a first temperature difference based on the inlet temperature and the outlet temperature; determine the fouling position of the air conditioner under the current operating condition according to the first temperature difference, the air outlet speed, the air outlet temperature and the air inlet temperature; if it is determined that the fouling position is the filter screen fouling, control the air conditioner to execute the filter screen self-cleaning mode; if it is determined that the fouling position is the heat exchanger fouling, control the air conditioner to execute the heat exchanger self-cleaning mode. By using this air conditioner, the fouling position of the air conditioner can be distinguished and the corresponding self-cleaning mode can be executed, thereby improving the user experience.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and in particular to an air conditioner and a self-cleaning control method for an air conditioner. Background Art

[0002] In related technologies, most of the existing methods for determining the self-cleaning of air conditioners are limited to whether there is dust accumulation in the overall indoor unit of the air conditioner, and it is impossible to specifically determine the components with dust accumulation, such as filters, evaporators, and fans. The main object of self-cleaning of the indoor unit of the air conditioner is the heat exchanger. As a result, when other components need to be self-cleaned, the air conditioner may misjudge that the heat exchanger needs to be self-cleaned and repeatedly perform self-cleaning on the heat exchanger. For example, when the filter is dirty and blocked while the heat exchanger is not dirty and blocked, at this time, the heat exchanger does not meet the conditions for self-cleaning. However, the built-in program of the air conditioner detects that the indoor unit of the air conditioner is dirty and blocked, and then performs self-cleaning on the heat exchanger according to the set self-cleaning strategy. But the actual situation is that the filter needs to be self-cleaned, resulting in misjudgment of the components that need to be self-cleaned, repeatedly performing self-cleaning on the heat exchanger, and the filter still has a dirty and blocked situation, reducing the user experience. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. For this reason, an object of the present invention is to provide an air conditioner that can distinguish the dirty and blocked positions of the air conditioner and execute corresponding self-cleaning modes, thereby improving the user experience.

[0004] A second object of the present invention is to provide a self-cleaning control method for an air conditioner.

[0005] To solve the above problems, an embodiment of the first aspect of the present invention provides an air conditioner, including: a refrigerant circulation circuit that circulates refrigerant in a circuit composed of a compressor, a condenser, an expansion valve, an evaporator, and a four-way valve; a compressor configured to compress low-temperature and low-pressure refrigerant gas into high-temperature and high-pressure refrigerant gas and discharge it to the condenser; a first heat exchanger and a second heat exchanger, where one operates as a condenser and the other operates as an evaporator; a four-way valve configured to control the flow direction of the refrigerant in the refrigerant circuit so as to switch the first heat exchanger and the second heat exchanger between acting as a condenser and an evaporator; a filter screen disposed on the indoor side and configured to filter the air input from the outdoor side into the indoor side; a first temperature sensor configured to collect the inlet temperature of the evaporator; a second temperature sensor configured to collect the outlet temperature of the evaporator; a third temperature sensor configured to collect the air outlet temperature of the air conditioner; a fourth temperature sensor configured to collect the air inlet temperature of the air conditioner; a speed sensor configured to collect the air outlet speed of the air conditioner; and a controller configured to: determine the current operating condition of the air conditioner; obtain the inlet temperature and the outlet temperature of the evaporator, obtain the air outlet speed of the air conditioner, and obtain the air outlet temperature and the air inlet temperature of the air conditioner; obtain a first temperature difference based on the inlet temperature and the outlet temperature; determine the fouling position of the air conditioner under the current operating condition based on the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature; if it is determined that the fouling position is a dirty filter screen, control the air conditioner to execute a filter screen self-cleaning mode; and if it is determined that the fouling position is a dirty heat exchanger, control the air conditioner to execute a heat exchanger self-cleaning mode.

[0006] For the air conditioner according to the embodiment of the present invention, after determining the current operating condition of the air conditioner, different filter screen fouling conditions or heat exchanger fouling conditions are preset in the controller according to the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature. Thus, by determining whether the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature meet the filter screen fouling conditions or the heat exchanger fouling conditions, the fouling position of the air conditioner is judged, thereby reducing the possibility of misjudging the fouling position of the air conditioner and improving the user experience.

[0007] In some embodiments, when determining the fouling position of the air conditioner under the current operating condition according to the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, the controller is specifically configured to: in the cooling condition of the air conditioner, obtain a first preset temperature difference, a first preset air outlet speed, a first preset temperature, and a second preset temperature; if it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is lower than the first preset temperature, then determine that the fouling position is the filter fouling; if it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is higher than the second preset temperature, then determine that the fouling position is the heat exchanger fouling; wherein, the second preset temperature is greater than the first preset temperature.

[0008] In some embodiments, the controller is further configured to: if it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is between the first preset temperature and the second preset temperature, then control the air conditioner to continue operating in the cooling condition. Or, obtain a second temperature difference according to the air outlet temperature and the air inlet temperature; if it is determined that the first temperature difference is higher than the first preset temperature difference, the air outlet speed is higher than the first preset air outlet speed, and the second temperature difference is higher than the second preset temperature difference, then control the air conditioner to continue operating in the cooling condition.

[0009] In some embodiments, when obtaining the first preset temperature difference, the first preset air outlet speed, the first preset temperature, and the second preset temperature, the controller is specifically configured to: obtain the operating duration, the indoor fan speed, the indoor coil temperature, and the working environment humidity of the air conditioner; determine the condensation state of the evaporator according to the operating duration, the air inlet temperature, and the working environment humidity; determine the first preset air outlet speed when the air conditioner is in a clean state according to the condensation state and the indoor fan speed; obtain the first preset air outlet temperature when the air conditioner is in a clean state according to the indoor coil temperature, the air inlet temperature, the indoor fan speed, and the condensation state; use the difference between the first preset air outlet temperature and the first allowable temperature error as the first preset temperature; use the sum of the first preset air outlet temperature and the first allowable temperature error as the second preset temperature; determine the first preset temperature difference when the air conditioner is in a clean state according to the outlet temperature and the inlet temperature.

[0010] In some embodiments, when determining the fouling location of the air conditioner under the current operating condition according to the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, the controller is specifically configured to: in the heating mode of the air conditioner, obtain a third preset temperature difference, a second preset air outlet speed, a third preset temperature, and a fourth preset temperature; if it is determined that the first temperature difference is lower than the third preset temperature difference, the air outlet speed is lower than the second preset air outlet speed, and the air outlet temperature is higher than the third preset temperature, then determine that the fouling location is the filter fouling; if it is determined that the first temperature difference is lower than the third preset temperature difference, the air outlet speed is lower than the second preset air outlet speed, and the air outlet temperature is lower than the fourth preset temperature, then determine that the fouling location is the heat exchanger fouling; wherein, the third preset temperature is greater than the fourth preset temperature.

[0011] In some embodiments, the controller is further configured to: if it is determined that the first temperature difference is lower than the third preset temperature difference, the air outlet speed is lower than the second preset air outlet speed, and the air outlet temperature is between the fourth preset temperature and the third preset temperature, then control the air conditioner to continue operating in the heating mode. Or, obtain a second temperature difference according to the air outlet temperature and the air inlet temperature; if it is determined that the first temperature difference is higher than the third preset temperature difference, the air outlet speed is higher than the second preset air outlet speed, and the second temperature difference is higher than the fourth preset temperature difference, then control the air conditioner to continue operating in the heating mode.

[0012] In some embodiments, when obtaining the third preset temperature difference, the second preset air outlet speed, the third preset temperature, and the fourth preset temperature, the controller is specifically configured to: obtain the indoor fan speed and the indoor coil temperature of the air conditioner; determine the second preset air outlet speed when the air conditioner is in a clean state according to the indoor fan speed; obtain the second preset air outlet temperature when the air conditioner is in a clean state according to the indoor coil temperature, the air inlet temperature, and the indoor fan speed; use the sum value of the second preset air outlet temperature and the second allowable temperature error as the third preset temperature; use the difference value between the second preset air outlet temperature and the second allowable temperature error as the fourth preset temperature; determine the third preset temperature difference when the air conditioner is in a clean state according to the outlet temperature and the inlet temperature.

[0013] In a second aspect embodiment of the present invention, a self-cleaning control method for an air conditioner is provided, including: determining the current operating condition of the air conditioner; obtaining the inlet temperature and the outlet temperature of the evaporator, obtaining the air outlet speed of the air conditioner, and obtaining the air outlet temperature and the air inlet temperature of the air conditioner; obtaining a first temperature difference based on the inlet temperature and the outlet temperature; determining the fouling position of the air conditioner under the current operating condition based on the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature; if it is determined that the fouling position is a filter fouling, controlling the air conditioner to execute a filter self-cleaning mode; if it is determined that the fouling position is a heat exchanger fouling, controlling the air conditioner to execute a heat exchanger self-cleaning mode.

[0014] According to the self-cleaning control method of the air conditioner in the embodiment of the present invention, after determining the current operating condition of the air conditioner, by presetting a filter fouling condition or a heat exchanger fouling condition in the controller according to the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, it is possible to determine the fouling position of the air conditioner by judging whether the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature meet the filter fouling condition or the heat exchanger fouling condition, thereby reducing the possibility of misjudging the fouling position of the air conditioner and improving the user experience.

[0015] In some embodiments, determining the fouling position of the air conditioner under the current operating condition based on the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature includes: in the refrigeration condition of the air conditioner, obtaining a first preset temperature difference, a first preset air outlet speed, a first preset temperature, and a second preset temperature; if it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is lower than the first preset temperature, determining that the fouling position is a filter fouling; if it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is higher than the second preset temperature, determining that the fouling position is a heat exchanger fouling; wherein, the second preset temperature is greater than the first preset temperature.

[0016] In some embodiments, determining the fouling location of the air conditioner under the current operating condition according to the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature includes: in the heating mode of the air conditioner, obtaining a third preset temperature difference, a second preset air outlet speed, a third preset temperature, and a fourth preset temperature; if it is determined that the first temperature difference is lower than the third preset temperature difference, the air outlet speed is lower than the second preset air outlet speed, and the air outlet temperature is higher than the third preset temperature, then it is determined that the fouling location is the filter fouled; if it is determined that the first temperature difference is lower than the third preset temperature difference, the air outlet speed is lower than the second preset air outlet speed, and the air outlet temperature is lower than the fourth preset temperature, then it is determined that the fouling location is the heat exchanger fouled; wherein, the third preset temperature is greater than the fourth preset temperature.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0019] Figure 1 is a perspective view of the appearance of an air conditioner according to an embodiment of the present invention;

[0020] Figure 2 is a schematic circuit diagram of the structure of an air conditioner according to an embodiment of the present invention;

[0021] Figure 3 is a block diagram of the structure of an air conditioner according to an embodiment of the present invention;

[0022] Figure 4 is a flowchart of a self-cleaning control method of an air conditioner in a cooling mode according to an embodiment of the present invention;

[0023] Figure 5 is a flowchart of a self-cleaning control method of an air conditioner in a cooling mode according to another embodiment of the present invention;

[0024] Figure 6 is a flowchart of a self-cleaning control method of an air conditioner in a heating mode according to an embodiment of the present invention;

[0025] Figure 7 is a flowchart of a self-cleaning control method of an air conditioner in a heating mode according to another embodiment of the present invention;

[0026] Figure 8 is a flowchart of a self-cleaning control method of an air conditioner according to an embodiment of the present invention;

[0027] Figure 9 is a flowchart of a self-cleaning control method for an air conditioner according to another embodiment of the present invention;

[0028] Figure 10 is a flowchart of a self-cleaning control method for an air conditioner according to another embodiment of the present invention.

[0029] Reference numerals:

[0030] 1: Air conditioner; 2: Outdoor unit; 3: Indoor unit; 4: Connecting pipe;

[0031] 11: Compressor; 12: First temperature sensor; 13: Second temperature sensor; 14: Expansion valve; 16: First heat exchanger; 17: Third temperature sensor; 18: Fourth temperature sensor; 19: Speed sensor; 22: Second heat exchanger; 29: Four-way valve; 31: Indoor fan; 50: Controller. Detailed implementation manners

[0032] Embodiments of the present invention will be described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Embodiments of the present invention will be described in detail below.

[0033] In this application, the air conditioner performs a refrigeration cycle by using a compressor, a condenser, an expansion valve, and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation, and supplies refrigerant to the air that has been conditioned and heat-exchanged.

[0034] The compressor compresses the refrigerant gas in a high-temperature and high-pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process.

[0035] The expansion valve expands the liquid-phase refrigerant in a high-temperature and high-pressure state condensed in the condenser into a low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor. The evaporator can achieve a refrigeration effect by using the latent heat of evaporation of the refrigerant to perform heat exchange with the material to be cooled. Throughout the cycle, the air conditioner can adjust the temperature of the indoor space.

[0036] The outdoor unit of the air conditioner refers to the part of the refrigeration cycle including the compressor and the outdoor heat exchanger. The indoor unit of the air conditioner includes the indoor heat exchanger, and the expansion valve can be provided in the indoor unit or the outdoor unit.

[0037] The indoor heat exchanger and the outdoor heat exchanger are used as condensers or evaporators. When the indoor heat exchanger is used as a condenser, the air conditioner serves as a heater in the heating mode, and when the indoor heat exchanger is used as an evaporator, the air conditioner serves as a cooler in the cooling mode.

[0038] Figure 1 The illustrated air conditioner 1 includes: an indoor unit 3. Taking an indoor wall-mounted unit (shown in the figure) as an example, the indoor wall-mounted unit is usually installed on the indoor wall surface. For another example, an indoor cabinet unit (not shown in the figure) is also a form of the indoor unit. An outdoor unit 2, which is usually installed outdoors and is used for heat exchange with the indoor environment.

[0039] Figure 2 The circuit structure of the air conditioner 1 is shown. The air conditioner 1 includes an indoor controller to control the operation of each component inside the air conditioner 1, so that the operation of each component of the air conditioner 1 realizes each predetermined function of the air conditioner 1.

[0040] In addition, as Figure 2 shown, the air conditioner 1 further includes a compressor 11, a first heat exchanger 16, an expansion valve 14, and a second heat exchanger 22. Among them, the first heat exchanger 16 and the second heat exchanger 22 operate as condensers or evaporators, that is, one of them operates as a condenser and the other operates as an evaporator. The compressor 11 sucks in the refrigerant from the suction port and discharges the compressed refrigerant inside from the discharge port to the first heat exchanger 16. The compressor 11 is a variable-capacity inverter compressor that performs speed control based on an inverter. The compressor 11 is used to compress the low-temperature and low-pressure refrigerant gas into a high-temperature and high-pressure refrigerant gas and discharge it to the condenser; the four-way valve 29 is used to control the flow direction of the refrigerant in the refrigerant circuit so that the first heat exchanger 16 and the second heat exchanger 22 are switched between being a condenser and an evaporator.

[0041] In the embodiment, as Figure 3 shown, the air conditioner 1 further includes a filter (not shown in the figure), a first temperature sensor 12, a second temperature sensor 13, a third temperature sensor 17, a fourth temperature sensor 18, and a speed sensor 19. Among them, the filter is provided on the indoor side and is used to filter the air input from the outdoor side to the indoor side; the first temperature sensor 12 is used to collect the inlet temperature of the evaporator; the second temperature sensor 13 is used to collect the outlet temperature of the evaporator; the third temperature sensor 17 is used to collect the air outlet temperature of the air conditioner 1; the fourth temperature sensor 18 is used to collect the air inlet temperature of the air conditioner 1; the speed sensor 19 is used to collect the air outlet speed of the air conditioner 1.

[0042] To solve the above problems, the controller 50 is configured to determine the fouling position of the air conditioner 1 through the following steps.

[0043] First, determine the current operating condition of the air conditioner 1.

[0044] Specifically, the air conditioner 1 turns on the cooling mode or the heating mode according to the magnitude of the outdoor ambient temperature. Therefore, the current operating condition of the air conditioner 1 is judged by the collected outdoor ambient temperature. If it is detected that the outdoor ambient temperature is higher than the temperature value preset according to the cooling mode, it indicates that the current operating condition of the air conditioner 1 is the cooling condition. Or if it is detected that the outdoor ambient temperature is lower than the temperature value preset according to the heating mode, it indicates that the current operating condition of the air conditioner 1 is the heating condition. And since the air conditioner 1 can increase or decrease the indoor ambient temperature through the cooling mode or the heating mode, the current operating condition of the air conditioner 1 is judged by the magnitude of the collected indoor ambient temperature. If it is continuously detected that the indoor ambient temperature is lower than the temperature value preset according to the cooling mode, it indicates that the current operating condition of the air conditioner 1 is the cooling condition. Or if it is detected that the indoor ambient temperature is higher than the temperature value preset according to the heating mode, it indicates that the current operating condition of the air conditioner 1 is the heating condition. And since the four-way valve states are different when the air conditioner 1 is in the cooling condition or the heating condition, that is, when the air conditioner 1 is in the heating condition, the four-way valve state is the energized state, and when the air conditioner 1 is in the cooling condition, the four-way valve state is the de-energized state. Therefore, the current operating condition of the air conditioner 1 can be judged by the four-way valve state obtained by the controller 50.

[0045] Secondly, obtain the inlet temperature and the outlet temperature of the evaporator, and obtain the air outlet speed of the air conditioner 1, and obtain the air outlet temperature and the air inlet temperature of the air conditioner 1.

[0046] Specifically, the inlet temperature of the evaporator is collected by the first temperature sensor 12, and the collected inlet temperature of the evaporator is transmitted to the controller 50; and the outlet temperature of the evaporator is collected by the second temperature sensor 13, and the collected outlet temperature of the evaporator is transmitted to the controller 50; and the air outlet speed of the air conditioner 1 is collected by the speed sensor 19, and the collected air outlet speed of the air conditioner 1 is transmitted to the controller 50; and the air outlet temperature of the air conditioner 1 is collected by the third temperature sensor 17, and the collected air outlet temperature of the air conditioner 1 is transmitted to the controller 50; and the air inlet temperature of the air conditioner 1 is collected by the fourth temperature sensor 18, and the collected air inlet temperature of the air conditioner 1 is transmitted to the controller 50.

[0047] Thirdly, obtain the first temperature difference according to the inlet temperature and the outlet temperature.

[0048] Specifically, the inlet temperature and the outlet temperature of the evaporator are subtracted to obtain the first temperature difference. Wherein, the first temperature difference = inlet temperature - outlet temperature.

[0049] Then, determine the fouling position of the air conditioner 1 under the current operating condition according to the first temperature difference, the air outlet speed, the air outlet temperature and the air inlet temperature.

[0050] Specifically, the existing self-cleaning determination method determines whether the entire indoor unit of the air conditioner 1 is dirty and blocked and requires self-cleaning, but it cannot determine the specific dirty and blocked components of the air conditioner 1. When the filter is dirty and blocked while the heat exchanger is not dirty and blocked, at this time, the heat exchanger is not dirty and blocked and does not meet the conditions for self-cleaning. However, the built-in program of the air conditioner 1 detects that the indoor unit of the air conditioner 1 is dirty and blocked, and then performs self-cleaning on the heat exchanger according to the set self-cleaning strategy. However, the actual situation is that the filter is dirty and blocked, resulting in misjudgment of the components that need to be self-cleaned, and repeatedly performing self-cleaning on the heat exchanger, so that the filter still has a dirty and blocked situation. To solve this problem, in this application, by judging the ranges of the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, the dirty and blocked position of the air conditioner 1 under the current operating conditions is determined. That is to say, when the filter or the heat exchanger is dirty and blocked, the filter or the heat exchanger affects the air outlet speed and the air intake volume of the air conditioner 1 due to the deposition of a large amount of dust, and further affects the difference between the air outlet temperature and the air inlet temperature of the air conditioner 1 and the heat exchange capacity of the heat exchanger, resulting in a decrease in the first temperature difference between the air outlet temperature of the air conditioner 1 and the evaporator. And because the influence of the dirty and blocked filter or heat exchanger on the heat exchange capacity of the heat exchanger is different, and the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature of the air conditioner 1 are different under the refrigeration condition or the heating condition, the controller 50 presets the filter dirty and blocked conditions and the heat exchanger dirty and blocked conditions of the air conditioner 1 under the current operating conditions through the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, and the filter dirty and blocked conditions are different from the heat exchanger dirty and blocked conditions. Thus, by judging whether the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature are within the filter dirty and blocked conditions or the heat exchanger dirty and blocked conditions, the dirty and blocked position of the air conditioner 1 is judged. Therefore, in this application, by judging the ranges of the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, the dirty and blocked position of the air conditioner 1 is judged, thereby reducing the possibility of misjudgment of the dirty and blocked position of the air conditioner 1 and improving the user experience.

[0051] Finally, if the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature meet the filter dirty and blocked conditions, it is determined that the dirty and blocked position is the filter dirty and blocked, and then the air conditioner 1 is controlled to execute the filter self-cleaning mode to clean the filter.

[0052] Moreover, if the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature meet the heat exchanger dirty and blocked conditions, it is determined that the dirty and blocked position of the air conditioner 1 is the heat exchanger dirty and blocked, and then the air conditioner 1 is controlled to execute the heat exchanger self-cleaning mode to clean the heat exchanger.

[0053] According to the air conditioner 1 of an embodiment of the present invention, after the controller 50 determines the current operating condition of the air conditioner 1, different filter clogging conditions or heat exchanger clogging conditions are preset in the controller 50 according to the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, so as to determine whether the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature meet the filter clogging conditions or the heat exchanger clogging conditions, so as to judge the clogging position of the air conditioner 1, thereby reducing the possibility of misjudging the clogging position of the air conditioner 1 and improving the user experience.

[0054] In some embodiments, when determining the clogging position of the air conditioner 1 under the current operating condition according to the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, as Figure 4 shown, the controller 50 is specifically configured to perform the following steps.

[0055] Step S40, in the refrigeration condition of the air conditioner, obtain a first preset temperature difference, a first preset air outlet speed, a first preset temperature, and a second preset temperature.

[0056] Step S41, if it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is lower than the first preset temperature, it is determined that the clogging position is a filter clog.

[0057] Step S42, if it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is higher than the second preset temperature, it is determined that the clogging position is a heat exchanger clog; wherein, the second preset temperature is greater than the first preset temperature.

[0058] Specifically, when the filter is severely clogged and the heat exchanger is not severely clogged, the filter affects the air inlet volume and air speed of the heat exchanger and the air outlet speed of the air conditioner 1 due to the deposition of a large amount of dust, and the theoretical heat exchange capacity of the heat exchanger is not affected. Therefore, when the air entering the air conditioner 1 during filter clogging exchanges heat with the heat exchanger, a small amount of air inlet volume releases more heat than the heat corresponding to this air inlet volume. At this time, the air outlet temperature of the air conditioner 1 is lower than the air outlet temperature corresponding to the air conditioner 1 during filter clogging, and the first temperature difference between the inlet temperature and the outlet temperature of the evaporator decreases. Therefore, in the refrigeration condition of the air conditioner 1, obtain a first preset temperature difference, a first preset air outlet speed, and a first preset temperature, and judge whether the clogging position is a filter clog by judging whether the first temperature difference is lower than the first preset temperature difference, whether the air outlet speed is lower than the first preset air outlet speed, and whether the air outlet temperature is lower than the first preset temperature. If it is determined that the first temperature difference is lower than the first preset temperature difference, it means that the actual heat exchange capacity of the heat exchanger has weakened, and if the air outlet speed is lower than the first preset air outlet speed, it means that the air outlet speed of the air conditioner 1 exceeds the error range, and the air outlet temperature of the air conditioner 1 is lower than the first preset temperature. At this time, the air outlet temperature of the air conditioner 1 is abnormal, and it is determined that the clogging position is a filter clog at this time.

[0059] Or when the heat exchanger is dirty and blocked while the filter screen is not, the air intake volume and air velocity passing through the filter screen are within the normal range, while the air intake volume and air velocity entering the heat exchanger decrease. At this time, due to the dirty blockage of the heat exchanger, the heat exchange capacity of the heat exchanger decreases. Therefore, when the air entering the air conditioner 1 exchanges heat with the heat exchanger when the heat exchanger is dirty and blocked, a small air intake volume releases less heat corresponding to this air intake volume, making the outlet air temperature of the air conditioner 1 higher than the outlet air temperature of the air conditioner 1 corresponding to when the heat exchanger is dirty and blocked, and the first temperature difference between the inlet temperature and the outlet temperature of the evaporator decreases. Therefore, under the refrigeration condition of the air conditioner 1, obtain the first preset temperature difference, the first preset outlet air velocity, and the second preset temperature, and determine whether the dirty blockage position is the dirty blockage of the heat exchanger by judging whether the first temperature difference is lower than the first preset temperature difference, whether the outlet air velocity is lower than the first preset outlet air velocity, and whether the outlet air temperature is higher than the second preset temperature. If it is determined that the first temperature difference is lower than the first preset temperature difference, it indicates that the actual heat exchange capacity of the heat exchanger has weakened, and if the outlet air velocity is lower than the first preset outlet air velocity, it indicates that the outlet air velocity has exceeded the error range, and if the outlet air temperature is higher than the second preset temperature, at this time, the outlet air temperature of the air conditioner 1 is abnormal, then it is determined that the dirty blockage position is the dirty blockage of the heat exchanger.

[0060] In some embodiments, as Figure 5 shown, the controller 50 is further configured to perform the following steps.

[0061] Step S43, if it is determined that the first temperature difference is lower than the first preset temperature difference, the outlet air velocity is lower than the first preset outlet air velocity, and the outlet air temperature is between the first preset temperature and the second preset temperature, then control the air conditioner to continue operating in the refrigeration condition.

[0062] Step S44, or obtain a second temperature difference according to the outlet air temperature and the inlet air temperature.

[0063] Step S45, if it is determined that the first temperature difference is higher than the first preset temperature difference, the outlet air velocity is higher than the first preset outlet air velocity, and the second temperature difference is higher than the second preset temperature difference, then control the air conditioner to continue operating in the refrigeration condition.

[0064] Specifically, since the sensor generates acquisition errors when obtaining the inlet temperature and outlet temperature of the evaporator, the air outlet speed and the air outlet temperature; and the air conditioner 1 generates fluctuation errors, errors in the indoor fan speed, superposition of errors caused by a small amount of dust accumulation, and aging errors during operation, resulting in a decrease in the air outlet temperature of the air conditioner 1 and a decrease in the first temperature difference. Therefore, it may be detected that the first temperature difference between the inlet temperature and the outlet temperature of the evaporator is lower than the first preset temperature difference. At this time, the heat exchange capacity of the heat exchanger has weakened, and it is detected that the air outlet speed of the air conditioner 1 is lower than the first preset air outlet speed, indicating that the air outlet speed of the air conditioner 1 exceeds the error range of the air outlet speed. However, if it is detected that the air outlet temperature is between the first preset temperature and the second preset temperature, and at this time the air outlet temperature of the air conditioner 1 is within the normal temperature range, it indicates that the filter screen and the heat exchanger are not dirty blocked, and then the air conditioner 1 is controlled to continue operating in the cooling mode.

[0065] Alternatively, by determining whether the first temperature difference is higher than the first preset temperature difference, whether the air outlet speed is higher than the first preset air outlet speed, and whether the second temperature difference is higher than the second preset temperature difference, to determine whether the air conditioner 1 needs to perform self-cleaning. First, the difference between the air outlet temperature and the air inlet temperature of the air conditioner 1 is calculated to obtain the second temperature difference. If it is determined that the first temperature difference is higher than the first preset temperature difference, it indicates that the heat exchange capacity of the heat exchanger has not weakened, and the air outlet speed is higher than the first preset air outlet speed, indicating that the air outlet speed is within the error range of the air outlet speed, and the second temperature difference is higher than the second preset temperature difference, indicating that the second temperature difference is within the temperature error range under the normal heat exchange capacity of the heat exchanger. At this time, the air conditioner 1 does not need to perform self-cleaning, and then the air conditioner 1 is controlled to continue operating in the cooling mode.

[0066] In some embodiments, when obtaining the first preset temperature difference, the first preset air outlet speed, the first preset temperature, and the second preset temperature, the controller 50 is specifically configured to: obtain the operating duration, the indoor fan speed, the indoor coil temperature, and the working environment humidity of the air conditioner 1; determine the condensation state of the evaporator according to the operating duration, the air inlet temperature, and the working environment humidity; determine the first preset air outlet speed when the air conditioner 1 is in the cleaning state according to the condensation state and the indoor fan speed; obtain the first preset air outlet temperature when the air conditioner 1 is in the cleaning state according to the indoor coil temperature, the air inlet temperature, the indoor fan speed, and the condensation state; use the difference between the first preset air outlet temperature and the first allowable temperature error as the first preset temperature; use the sum of the first preset air outlet temperature and the first allowable temperature error as the second preset temperature; determine the first preset temperature difference when the air conditioner 1 is in the cleaning state according to the outlet temperature and the inlet temperature.

[0067] In an embodiment, before the air conditioner leaves the factory, it is assumed by default that the air conditioner is in a clean state, that is, neither the filter nor the heat exchanger of the air conditioner is clogged. Therefore, at this time, the air conditioner is tested to detect and store the condensation states corresponding to different operating durations, different inlet air temperatures, and different working environment humidities when the air conditioner is in a clean state. That is to say, there is a one-to-one correspondence between the operating duration, the inlet air temperature, the working environment humidity, and the condensation state; and, detect and store the first preset air outlet speed corresponding to different condensation states and different indoor fan speeds when the air conditioner is in a clean state. That is to say, there is a one-to-one correspondence between the condensation state, the indoor fan speed, and the first preset air outlet speed; and, detect and store the first preset air outlet temperature corresponding to different indoor coil temperatures, different inlet air temperatures, different indoor fan speeds, and different condensation states when the air conditioner is in a clean state. That is to say, there is a one-to-one correspondence between the indoor coil temperature, the inlet air temperature, the indoor fan speed, the condensation state, and the first preset air outlet temperature; and, detect and store the first preset temperature difference corresponding to different outlet temperatures and different inlet temperatures when the air conditioner is in a clean state. That is to say, there is a one-to-one correspondence between the outlet temperature, the inlet temperature, and the first preset temperature difference.

[0068] Specifically, after the air conditioner 1 operates in the cooling condition for a period of time, condensed water, i.e., dew, will be generated on the evaporator. The dew accumulated on the evaporator increases with the increase of the operating duration of the air conditioner 1, and the dew state on the evaporator maintains a relatively stable state under the cooling condition. The time when the dew state reaches the stable state is related to the inlet air temperature, the working environment humidity, and the operating duration of the air conditioner 1. Moreover, the greater the inlet air temperature and the working environment humidity of the air conditioner 1, the more dew will be generated on the evaporator, and the longer the operating duration of the air conditioner 1, the more stable the dew state of the evaporator. Therefore, based on the corresponding relationship between the operating duration, the inlet air temperature, the working environment humidity, and the dew state stored before the air conditioner leaves the factory as described above, the dew state of the evaporator can be determined by the actually detected operating duration, inlet air temperature, and working environment humidity. Herein, the dew state can be understood as the water hanging amount on the evaporator. The water hanging amount on the evaporator will affect the inlet air volume and the air outlet speed of the evaporator, and when the water hanging amount on the evaporator is zero, the inlet air volume and the air outlet speed of the evaporator can be obtained according to the indoor fan speed. Therefore, based on the corresponding relationship between the dew state and the indoor fan speed and the first preset air outlet speed stored before the air conditioner leaves the factory as described above, the first preset air outlet speed when the air conditioner 1 is in the clean state can be determined according to the actually detected dew state and the indoor fan speed. And the first preset air outlet speed is a variable value, that is, different dew states and indoor fan speeds correspond to different first preset air outlet speeds. Since when the air conditioner 1 is in the stable operating state, the indoor coil temperature is in a relatively stable state, and both the dew state and the inlet air temperature of the evaporator will affect the heat exchange capacity of the evaporator. When the dew state of the evaporator is stable, the decrease of the inlet air temperature of the air conditioner 1 is in the direction of the coil temperature. Therefore, based on the corresponding relationship between the indoor coil temperature, the inlet air temperature, the indoor fan speed, and the dew state and the first preset air outlet temperature stored before the air conditioner leaves the factory as described above, when the indoor fan speed and the dew state are stable, the first preset air outlet temperature when the air conditioner 1 is in the clean state can be obtained. And the first preset air outlet temperature is a variable value, that is, different indoor fan speeds and dew states correspond to different first preset air outlet temperatures. Then, the sum value of the first preset air outlet temperature and the first allowable temperature error is used as the second preset temperature, and the second preset temperature is a variable value, that is, different first preset air outlet temperatures and first allowable temperature errors correspond to different second preset temperatures. Moreover, based on the corresponding relationship between the outlet temperature and the inlet temperature and the first preset temperature difference stored before the air conditioner leaves the factory as described above, the first preset temperature difference when the air conditioner 1 is in the clean state can be determined according to the outlet temperature and the inlet temperature when the air conditioner 1 is in the clean state. And the first preset temperature difference is a variable value, that is, different outlet temperatures and inlet temperatures correspond to different first preset temperature differences.

[0069] In some embodiments, when determining the fouling position of the air conditioner 1 under the current operating conditions according to the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, as Figure 6 shown, the controller 50 is specifically configured to perform the following steps.

[0070] Step S46, in the heating mode of the air conditioner, obtain a third preset temperature difference, a second preset air outlet speed, a third preset temperature, and a fourth preset temperature.

[0071] Step S47, if it is determined that the first temperature difference is lower than the third preset temperature difference, the air outlet speed is lower than the second preset air outlet speed, and the air outlet temperature is higher than the third preset temperature, then determine that the fouling position is the filter fouling.

[0072] Step S48, if it is determined that the first temperature difference is lower than the third preset temperature difference, the air outlet speed is lower than the second preset air outlet speed, and the air outlet temperature is lower than the fourth preset temperature, then determine that the fouling position is the heat exchanger fouling; wherein, the third preset temperature is greater than the fourth preset temperature.

[0073] Specifically, when the filter is severely fouled and the heat exchanger is not severely fouled, the filter affects the air inlet volume, air speed of the heat exchanger, and the air outlet speed of the air conditioner 1 due to the deposition of a large amount of dust, while the theoretical heat exchange capacity of the heat exchanger is not affected. Therefore, when the air entering the air conditioner 1 exchanges heat with the heat exchanger when the filter is fouled, a small amount of air inlet volume releases more heat than the heat corresponding to this air inlet volume. At this time, the air outlet temperature of the air conditioner 1 is lower than the air outlet temperature corresponding to the air conditioner 1 when the filter is fouled, and the first temperature difference between the inlet temperature and the outlet temperature of the evaporator decreases. Therefore, in the heating mode of the air conditioner 1, obtain a third preset temperature difference, a second preset air outlet speed, and a third preset temperature, and determine whether the fouling position is the filter fouling by judging whether the first temperature difference is lower than the third preset temperature difference, whether the air outlet speed is lower than the second preset air outlet speed, and whether the air outlet temperature is higher than the third preset temperature. If it is determined that the first temperature difference is lower than the third preset temperature difference, it means that the heat exchange capacity of the heat exchanger has weakened, and if the air outlet speed is lower than the second preset air outlet speed, it means that the air outlet speed has exceeded the error range of the air speed, and if the air outlet temperature is higher than the third preset temperature, it means that the air outlet temperature has decreased and is lower than the air outlet temperature when the filter is not fouled, and the air outlet temperature of the air conditioner 1 is in an abnormal state, then determine that the fouling position is the filter fouling.

[0074] Or when the heat exchanger is dirty and blocked while the filter screen is not, the air intake volume and air velocity passing through the filter screen are within the normal range, while the air intake volume and air velocity entering the heat exchanger decrease. At this time, due to the dirty blockage of the heat exchanger, the heat exchange capacity of the heat exchanger decreases. Therefore, when the air entering the air conditioner 1 exchanges heat with the heat exchanger when the heat exchanger is dirty and blocked, a small air intake volume releases less heat corresponding to this air intake volume, making the outlet air temperature of the air conditioner 1 higher than the outlet air temperature corresponding to the air conditioner 1 when the heat exchanger is dirty and blocked, and the first temperature difference between the inlet temperature and the outlet temperature of the evaporator decreases. Therefore, in the heating mode of the air conditioner 1, the third preset temperature difference, the second preset outlet air velocity, and the fourth preset temperature are obtained. By judging whether the first temperature difference is lower than the third preset temperature difference, whether the outlet air velocity is lower than the second preset outlet air velocity, and whether the outlet air temperature is lower than the fourth preset temperature, it is determined whether the dirty blockage position of the air conditioner 1 is the filter screen dirty blockage in the heating mode. If it is determined that the first temperature difference is lower than the third preset temperature difference, it indicates that the heat exchange capacity of the heat exchanger has weakened. If the outlet air velocity is lower than the second preset outlet air velocity, it indicates that the outlet air velocity has exceeded the error range. If the outlet air temperature is lower than the fourth preset temperature, it indicates that the outlet air temperature has decreased and is lower than the outlet air temperature when the heat exchanger is not dirty and blocked, and the outlet air temperature is in an abnormal state, then it is determined that the dirty blockage position is the heat exchanger dirty blockage.

[0075] In some embodiments, as Figure 7 shown, the controller 50 is further configured to perform the following steps.

[0076] Step S49, if it is determined that the first temperature difference is lower than the third preset temperature difference, the outlet air velocity is lower than the second preset outlet air velocity, and the outlet air temperature is between the fourth preset temperature and the third preset temperature, then control the air conditioner to continue operating in the heating mode.

[0077] Step S50, or, obtain the second temperature difference according to the outlet air temperature and the inlet air temperature.

[0078] Step S51, if it is determined that the first temperature difference is higher than the third preset temperature difference, the outlet air velocity is higher than the second preset outlet air velocity, and the second temperature difference is higher than the fourth preset temperature difference, then control the air conditioner to continue operating in the heating mode.

[0079] Specifically, since there are acquisition errors when the sensor obtains the inlet temperature and outlet temperature of the evaporator, the air outlet speed and the air outlet temperature; and there are fluctuation errors, errors in the indoor fan speed, superposition of errors caused by a small amount of dust accumulation, and aging errors of the air conditioner 1 during the operation of the air conditioner 1, resulting in a decrease in the air outlet temperature and the first temperature difference of the air conditioner 1. Therefore, it may be detected that the first temperature difference is lower than the third preset temperature difference. At this time, the heat exchange capacity of the heat exchanger has weakened, and the air outlet speed is lower than the second preset air outlet speed, indicating that the air outlet speed has exceeded the error range, and the air outlet temperature is between the fourth preset temperature and the third preset temperature, indicating that the air outlet temperature of the air conditioner 1 is within the normal range. At this time, the air conditioner 1 does not need to perform self-cleaning, and the air conditioner 1 is controlled to continue operating in the heating mode.

[0080] Alternatively, by judging whether the first temperature difference is higher than the third preset temperature difference, whether the air outlet speed is higher than the second preset air outlet speed, and whether the second temperature difference is higher than the fourth preset temperature difference, to judge whether the air conditioner 1 needs to perform self-cleaning. First, the air outlet temperature and the inlet temperature are subtracted to obtain the second temperature difference. If it is determined that the first temperature difference is higher than the third preset temperature difference, it means that the heat exchange capacity of the heat exchanger has not weakened, and the air outlet speed is higher than the second preset air outlet speed, indicating that the air outlet speed is within the error range of the air outlet speed. And if the second temperature difference is higher than the fourth preset temperature difference, it means that the second temperature difference is within the temperature difference error range corresponding to the normal heat exchange capacity of the heat exchanger. At this time, the air conditioner 1 does not need to perform self-cleaning, and the air conditioner 1 is controlled to continue operating in the heating mode.

[0081] In some embodiments, when obtaining the third preset temperature difference, the second preset air outlet speed, the third preset temperature, and the fourth preset temperature, the controller 50 is specifically configured to: obtain the indoor fan speed and the indoor coil temperature of the air conditioner 1; determine the second preset air outlet speed when the air conditioner 1 is in the cleaning state according to the indoor fan speed; obtain the second preset air outlet temperature when the air conditioner 1 is in the cleaning state according to the indoor coil temperature, the inlet temperature, and the indoor fan speed; use the sum of the second preset air outlet temperature and the second allowable temperature error as the third preset temperature; use the difference between the second preset air outlet temperature and the second allowable temperature error as the fourth preset temperature; determine the third preset temperature difference when the air conditioner 1 is in the cleaning state according to the outlet temperature and the inlet temperature.

[0082] In an embodiment, before the air conditioner leaves the factory, it is defaulted that the air conditioner is in a clean state, that is, neither the filter nor the heat exchanger of the air conditioner is clogged. Therefore, at this time, the air conditioner is tested to detect and store the second preset air outlet speed corresponding to different indoor fan speeds when the air conditioner is in a clean state. That is to say, there is a one-to-one correspondence between the indoor fan speed and the second preset air outlet speed; and, detect and store the second preset air outlet temperature corresponding to different indoor coil temperatures, different inlet air temperatures, and different indoor fan speeds when the air conditioner is in a clean state. That is to say, there is a one-to-one correspondence between the indoor coil temperature, the inlet air temperature, and the indoor fan speed and the second preset air outlet temperature; and, detect and store the third preset temperature difference corresponding to different outlet temperatures and different inlet temperatures when the air conditioner is in a clean state. That is to say, there is a one-to-one correspondence between the outlet temperature and the inlet temperature and the third preset temperature difference.

[0083] Specifically, since condensation will not occur on the evaporator when the air conditioner 1 is in the heating mode, parameters can be obtained when the air conditioner 1 operates stably. That is, when the air conditioner 1 operates stably, the indoor fan speed and the indoor coil temperature of the air conditioner 1 are obtained. Thus, based on the corresponding relationship between the indoor fan speed and the second preset air outlet speed stored before the air conditioner leaves the factory as described above, during actual use, the second preset air outlet speed when the air conditioner 1 is in the clean state can be determined. And the second preset air outlet speed is a variable value, that is, different indoor fan speeds correspond to different second preset air outlet speeds. And it is detected according to the indoor coil temperature, the inlet air temperature and the indoor fan speed when the air conditioner 1 is in the heating mode. Thus, based on the corresponding relationship between the indoor coil temperature, the inlet air temperature, the indoor fan speed and the second preset air outlet temperature stored before the air conditioner leaves the factory as described above, the second preset air outlet temperature when the air conditioner 1 is in the clean state can be obtained. And the second preset air outlet temperature is a variable value, that is, different indoor coil temperatures, inlet air temperatures and indoor fan speeds correspond to different second preset air outlet temperatures. And the second preset air outlet temperature is added to the second allowable temperature error, and the sum value is used as the third preset temperature and the third preset temperature is a variable value, that is, different second preset air outlet temperatures and second allowable temperature errors correspond to different third preset temperatures. The second preset air outlet temperature is subtracted from the second allowable temperature error to use the difference value as the fourth preset temperature, and the fourth preset temperature is a variable value, that is, different second preset air outlet temperatures and second allowable temperature errors correspond to different fourth preset temperatures. And thus, based on the corresponding relationship between the outlet temperature and the inlet temperature and the third preset temperature difference stored before the air conditioner leaves the factory as described above, the outlet temperature and the inlet temperature when the air conditioner 1 is in the heating mode and the air conditioner 1 is in the clean state are subtracted to determine the third preset temperature difference when the air conditioner 1 is in the clean state. And the third preset temperature difference is a variable value, that is, different outlet temperatures and inlet temperatures correspond to different third preset temperature differences.

[0084] An embodiment of the second aspect of the present invention provides a self-cleaning control method for an air conditioner, as Figure 8 shown, the method includes: step S1 - step S6.

[0085] Step S1, determine the current operating condition of the air conditioner.

[0086] Specifically, the air conditioner turns on the cooling mode or the heating mode according to the magnitude of the outdoor ambient temperature. Therefore, the current operating condition of the air conditioner is judged based on the collected outdoor ambient temperature. If it is detected that the outdoor ambient temperature is higher than the temperature value preset according to the cooling mode, it indicates that the current operating condition of the air conditioner is the cooling condition. Or if it is detected that the outdoor ambient temperature is lower than the temperature value preset according to the heating mode, it indicates that the current operating condition of the air conditioner is the heating condition. And since the air conditioner can increase or decrease the indoor ambient temperature through the cooling mode or the heating mode, the current operating condition of the air conditioner is judged based on the magnitude of the collected indoor ambient temperature. If it is continuously detected that the indoor ambient temperature is lower than the temperature value preset according to the cooling mode, it indicates that the current operating condition of the air conditioner is the cooling condition. Or if it is detected that the indoor ambient temperature is higher than the temperature value preset according to the heating mode, it indicates that the current operating condition of the air conditioner is the heating condition. And since the state of the four-way valve is different when the air conditioner is in the cooling condition or the heating condition, that is, when the air conditioner is in the heating condition, the state of the four-way valve is the energized state, and when the air conditioner is in the cooling condition, the state of the four-way valve is the de-energized state. Therefore, the current operating condition of the air conditioner can be judged based on the state of the four-way valve obtained by the controller.

[0087] Step S2, obtain the inlet temperature and the outlet temperature of the evaporator, and obtain the air outlet speed of the air conditioner, and obtain the air outlet temperature and the air inlet temperature of the air conditioner.

[0088] Specifically, collect the inlet temperature of the evaporator through the first temperature sensor and transmit the collected inlet temperature of the evaporator to the controller; and collect the outlet temperature of the evaporator through the second temperature sensor and transmit the collected outlet temperature of the evaporator to the controller; and collect the air outlet speed of the air conditioner through the speed sensor and transmit the collected air outlet speed of the air conditioner to the controller; and collect the air outlet temperature of the air conditioner through the third temperature sensor and transmit the collected air outlet temperature of the air conditioner to the controller; and collect the air inlet temperature of the air conditioner through the fourth temperature sensor and transmit the collected air inlet temperature of the air conditioner to the controller.

[0089] Step S3, obtain the first temperature difference according to the inlet temperature and the outlet temperature.

[0090] Wherein, the first temperature difference = inlet temperature - outlet temperature.

[0091] Step S4, determine the fouling position of the air conditioner under the current operating condition according to the first temperature difference, the air outlet speed, the air outlet temperature and the air inlet temperature.

[0092] Specifically, the existing self-cleaning determination method determines whether the indoor unit of the air conditioner is dirty and blocked and requires self-cleaning, but it cannot determine the specific dirty and blocked components of the air conditioner. When the filter is dirty and blocked while the heat exchanger is not dirty and blocked, at this time, the heat exchanger is not dirty and blocked and does not meet the conditions for self-cleaning. However, the built-in program of the air conditioner detects that the indoor unit of the air conditioner is dirty and blocked, and then performs self-cleaning on the heat exchanger according to the set self-cleaning strategy. But the actual situation is that the filter is dirty and blocked, resulting in misjudgment of the components that need to be self-cleaned, and repeatedly performing self-cleaning on the heat exchanger, so that the filter still has a dirty and blocked situation. To solve this problem, in this application, by judging the ranges of the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, the dirty and blocked position of the air conditioner under the current operating conditions is determined. That is to say, when the filter or the heat exchanger is dirty and blocked, the filter or the heat exchanger affects the air outlet speed and the air inlet volume of the air conditioner due to the deposition of a large amount of dust, and further affects the difference between the air outlet temperature and the air inlet temperature of the air conditioner and the heat exchange capacity of the heat exchanger, resulting in a decrease in the first temperature difference between the air outlet temperature of the air conditioner and the evaporator. And because the influence of the dirty and blocked filter or heat exchanger on the heat exchange capacity of the heat exchanger is different, and the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature of the air conditioner are different under the refrigeration condition or the heating condition, the controller presets the filter dirty and blocked conditions and the heat exchanger dirty and blocked conditions of the air conditioner under the current operating conditions through the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, and the filter dirty and blocked conditions are different from the heat exchanger dirty and blocked conditions. Thus, by judging whether the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature are within the filter dirty and blocked conditions or the heat exchanger dirty and blocked conditions, the dirty and blocked position of the air conditioner is judged. Therefore, in this application, by judging the ranges of the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, the dirty and blocked position of the air conditioner is judged, thereby reducing the possibility of misjudging the dirty and blocked position of the air conditioner and improving the user experience.

[0093] Step S5, if it is determined that the dirty and blocked position is the filter dirty and blocked, then control the air conditioner to execute the filter self-cleaning mode.

[0094] Step S6, if it is determined that the dirty and blocked position is the heat exchanger dirty and blocked, then control the air conditioner to execute the heat exchanger self-cleaning mode.

[0095] According to the self-cleaning control method of the air conditioner according to the embodiment of the present invention, after determining the current operating conditions of the air conditioner, by presetting the filter dirty and blocked conditions or the heat exchanger dirty and blocked conditions in the controller according to the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, thereby judging whether the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature meet the filter dirty and blocked conditions or the heat exchanger dirty and blocked conditions, to judge the dirty and blocked position of the air conditioner, thereby reducing the possibility of misjudging the dirty and blocked position of the air conditioner and improving the user experience.

[0096] In some embodiments, determining the fouling position of an air conditioner under the current operating conditions according to the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature includes: in the refrigeration mode of the air conditioner, obtaining a first preset temperature difference, a first preset air outlet speed, a first preset temperature, and a second preset temperature; if it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is lower than the first preset temperature, then it is determined that the fouling position is the filter fouling; if it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is higher than the second preset temperature, then it is determined that the fouling position is the heat exchanger fouling; wherein, the second preset temperature is greater than the first preset temperature.

[0097] Specifically, when the filter is severely fouled and the heat exchanger is not severely fouled, the filter affects the air inlet volume and air speed of the heat exchanger and the air outlet speed of the air conditioner due to the deposition of a large amount of dust, and the theoretical heat exchange capacity of the heat exchanger is not affected. Therefore, when the air entering the air conditioner exchanges heat with the heat exchanger when the filter is fouled, a small amount of air inlet volume releases more heat than the heat corresponding to this air inlet volume. At this time, the air outlet temperature of the air conditioner is lower than the air outlet temperature of the air conditioner when the filter is fouled, and the first temperature difference between the inlet temperature and the outlet temperature of the evaporator decreases. Therefore, in the refrigeration mode of the air conditioner, a first preset temperature difference, a first preset air outlet speed, and a first preset temperature are obtained, and by judging whether the first temperature difference is lower than the first preset temperature difference, whether the air outlet speed is lower than the first preset air outlet speed, and whether the air outlet temperature is lower than the first preset temperature, to judge whether the fouling position is the filter fouling. If it is determined that the first temperature difference is lower than the first preset temperature difference, it means that the actual heat exchange capacity of the heat exchanger has weakened, and the air outlet speed is lower than the first preset air outlet speed, which means that the air outlet speed of the air conditioner exceeds the error range, and the air outlet temperature of the air conditioner is lower than the first preset temperature. At this time, the air outlet temperature of the air conditioner is abnormal, and then it is determined that the fouling position is the filter fouling.

[0098] Or when the heat exchanger is dirty and blocked while the filter screen is not, the air intake volume and air velocity passing through the filter screen are within the normal range, while the air intake volume and air velocity entering the heat exchanger decrease. At this time, due to the dirty blockage of the heat exchanger, the heat exchange capacity of the heat exchanger decreases. Therefore, when the air entering the air conditioner exchanges heat with the heat exchanger when the heat exchanger is dirty and blocked, a small air intake volume releases less heat corresponding to this air intake volume, resulting in the outlet air temperature of the air conditioner being higher than the outlet air temperature corresponding to the air conditioner when the heat exchanger is dirty and blocked, and the first temperature difference between the inlet temperature and the outlet temperature of the evaporator decreases. Therefore, under the refrigeration condition of the air conditioner, obtain the first preset temperature difference, the first preset outlet air velocity, and the second preset temperature, and determine whether the dirty blockage position is the dirty blockage of the heat exchanger by judging whether the first temperature difference is lower than the first preset temperature difference, whether the outlet air velocity is lower than the first preset outlet air velocity, and whether the outlet air temperature is higher than the second preset temperature. If it is determined that the first temperature difference is lower than the first preset temperature difference, it indicates that the actual heat exchange capacity of the heat exchanger has weakened, and if the outlet air velocity is lower than the first preset outlet air velocity, it indicates that the outlet air velocity has exceeded the error range, and if the outlet air temperature is higher than the second preset temperature, at this time the outlet air temperature of the air conditioner is abnormal, then determine that the dirty blockage position is the dirty blockage of the heat exchanger.

[0099] In some embodiments, determining the dirty blockage position of the air conditioner under the current operating condition according to the first temperature difference, the outlet air velocity, the outlet air temperature, and the inlet air temperature includes: under the heating condition of the air conditioner, obtain the third preset temperature difference, the second preset outlet air velocity, the third preset temperature, and the fourth preset temperature; if it is determined that the first temperature difference is lower than the third preset temperature difference, the outlet air velocity is lower than the second preset outlet air velocity, and the outlet air temperature is higher than the third preset temperature, then determine that the dirty blockage position is the dirty blockage of the filter screen; if it is determined that the first temperature difference is lower than the third preset temperature difference, the outlet air velocity is lower than the second preset outlet air velocity, and the outlet air temperature is lower than the fourth preset temperature, then determine that the dirty blockage position is the dirty blockage of the heat exchanger; wherein, the third preset temperature is greater than the fourth preset temperature.

[0100] Specifically, when the filter screen is severely clogged and the heat exchanger is not severely clogged, the filter screen affects the air intake volume, air velocity of the heat exchanger, and the air outlet velocity of the air conditioner due to the deposition of a large amount of dust. However, the theoretical heat exchange capacity of the heat exchanger is not affected. Therefore, when the air entering the air conditioner exchanges heat with the heat exchanger when the filter screen is clogged, a small air intake volume releases more heat than the heat corresponding to this air intake volume. At this time, the air outlet temperature of the air conditioner is lower than the air outlet temperature corresponding to the air conditioner when the filter screen is clogged, and the first temperature difference between the inlet temperature and the outlet temperature of the evaporator decreases. Therefore, under the heating condition of the air conditioner, a third preset temperature difference, a second preset air outlet velocity, and a third preset temperature are obtained. By judging whether the first temperature difference is lower than the third preset temperature difference, whether the air outlet velocity is lower than the second preset air outlet velocity, and whether the air outlet temperature is higher than the third preset temperature, it is determined whether the clogged position is the filter screen clogging. If it is determined that the first temperature difference is lower than the third preset temperature difference, it indicates that the heat exchange capacity of the heat exchanger has weakened. If the air outlet velocity is lower than the second preset air outlet velocity, it indicates that the air outlet velocity has exceeded the error range of the air outlet velocity. If the air outlet temperature is higher than the third preset temperature, it indicates that the air outlet temperature has decreased and is lower than the air outlet temperature when the filter screen is not clogged, and the air outlet temperature of the air conditioner is in an abnormal state. Then, it is determined that the clogged position is the filter screen clogging.

[0101] Or when the heat exchanger is clogged and the filter screen is not clogged, the air intake volume and air velocity passing through the filter screen are within the normal range, while the air intake volume and air velocity entering the heat exchanger decrease. At this time, due to the clogging of the heat exchanger, the heat exchange capacity of the heat exchanger decreases. Therefore, when the air entering the air conditioner exchanges heat with the heat exchanger when the heat exchanger is clogged, a small air intake volume releases less heat than the heat corresponding to this air intake volume, resulting in the air outlet temperature of the air conditioner being higher than the air outlet temperature corresponding to the air conditioner when the heat exchanger is clogged, and the first temperature difference between the inlet temperature and the outlet temperature of the evaporator decreases. Therefore, under the heating condition of the air conditioner, a third preset temperature difference, a second preset air outlet velocity, and a fourth preset temperature are obtained. By judging whether the first temperature difference is lower than the third preset temperature difference, whether the air outlet velocity is lower than the second preset air outlet velocity, and whether the air outlet temperature is lower than the fourth preset temperature, it is determined whether the clogged position of the air conditioner is the filter screen clogging under the heating condition. If it is determined that the first temperature difference is lower than the third preset temperature difference, it indicates that the heat exchange capacity of the heat exchanger has weakened. If the air outlet velocity is lower than the second preset air outlet velocity, it indicates that the air outlet velocity has exceeded the error range. If the air outlet temperature is lower than the fourth preset temperature, it indicates that the air outlet temperature has decreased and is lower than the air outlet temperature when the heat exchanger is not clogged, and the air outlet temperature is in an abnormal state. Then, it is determined that the clogged position is the heat exchanger clogging.

[0102] The following refers to Figure 9 the following for an example of the self-cleaning control method of the air conditioner according to the embodiment of the present invention. The specific content is as follows.

[0103] Step S7, the compressor of the air conditioner operates stably at a certain frequency, and the indoor fan operates stably at a certain speed.

[0104] Step S8, obtain the indoor ambient temperature, outdoor ambient temperature and the status of the four-way valve, and judge the current operating condition of the air conditioner.

[0105] Step S9, if the current operating condition of the air conditioner is the cooling condition, obtain the indoor coil temperature, indoor fan speed, inlet temperature and outlet temperature of the evaporator, the air outlet speed, air outlet temperature, inlet air temperature, operating duration and working environment humidity of the air conditioner.

[0106] Step S10, determine the condensation state of the evaporator based on the operating duration, inlet air temperature and working environment humidity of the air conditioner.

[0107] Step S11, obtain the first preset air outlet temperature, first preset air outlet speed, first preset temperature and second preset temperature according to the indoor coil temperature, air outlet temperature, inlet air temperature, indoor fan speed and condensation state.

[0108] Step S12, compare the first temperature difference with the first preset temperature difference, and compare the air outlet speed with the first preset air outlet speed, and execute Step S13 or Step S16.

[0109] Step S13, if the first temperature difference is higher than the first preset temperature difference, and the air outlet speed is higher than the first preset air outlet speed.

[0110] Step S14, and the second temperature difference is higher than the second preset temperature difference.

[0111] Step S15, then the air conditioner does not need to perform self-cleaning.

[0112] Step S16, if the first temperature difference is lower than the first preset temperature difference, and the air outlet speed is lower than the first preset air outlet speed, execute Step S17, Step S19 or Step S21.

[0113] Step S17, and the air outlet temperature is lower than the first preset temperature.

[0114] Step S18, the fouled position is the filter fouled.

[0115] Step S19, and the air outlet temperature is between the first preset temperature and the second preset temperature.

[0116] Step S20, the air conditioner does not need to perform self-cleaning.

[0117] Step S21, and the air outlet temperature is higher than the second preset temperature.

[0118] Step S22, the fouled position is the heat exchanger fouled.

[0119] The following is an example of the self-cleaning control method for an air conditioner according to an embodiment of the present invention with reference to Figure 10 that shown below, and the specific content is as follows.

[0120] Step S7, the compressor of the air conditioner operates stably at a certain frequency, and the indoor fan operates stably at a certain speed.

[0121] Step S8, obtain the indoor environmental temperature, the outdoor environmental temperature, and the status of the four-way valve, and judge the current operating condition of the air conditioner.

[0122] Step S23, if the current operating condition of the air conditioner is the heating condition, obtain the indoor coil temperature, the inlet temperature and the outlet temperature of the evaporator, the air outlet speed, the air outlet temperature, and the air inlet temperature of the air conditioner.

[0123] Step S24, determine the second preset air outlet speed, the second preset air outlet temperature, and the third preset temperature difference according to the air inlet temperature, the indoor coil temperature, and the indoor fan speed.

[0124] Step S25, compare the first temperature difference with the third preset temperature difference, and compare the air outlet speed with the second preset air outlet speed, and execute Step S26 or Step S29.

[0125] Step S26, if the first temperature difference is higher than the third preset temperature difference, and the air outlet speed is higher than the second preset air outlet speed.

[0126] Step S27, and the second temperature difference is higher than the fourth preset temperature difference.

[0127] Step S28, then the air conditioner does not need to perform self-cleaning.

[0128] Step S29, if the first temperature difference is lower than the third preset temperature difference, and the air outlet speed is lower than the second preset air outlet speed, execute Step S30, Step S32, or Step S34.

[0129] Step S30, and the air outlet temperature is higher than the third preset temperature.

[0130] Step S31, the fouling position is the filter fouling.

[0131] Step S32, and the air outlet temperature is between the fourth preset temperature and the third preset temperature.

[0132] Step S33, the air conditioner does not need to perform self-cleaning.

[0133] Step S34, and the air outlet temperature is lower than the fourth preset temperature.

[0134] Step S35, the fouling position is the heat exchanger fouling.

[0135] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

[0136] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An air conditioner, characterized in that, Comprising: A refrigerant circulation circuit that circulates refrigerant in a circuit composed of a compressor, a condenser, an expansion valve, an evaporator, and a four-way valve; A compressor for compressing low-temperature and low-pressure refrigerant gas into high-temperature and high-pressure refrigerant gas and discharging it to the condenser; A first heat exchanger and a second heat exchanger, where one operates as a condenser and the other operates as an evaporator; A four-way valve for controlling the refrigerant flow direction in the refrigerant circulation circuit to enable switching between the first heat exchanger and the second heat exchanger as a condenser and an evaporator; A filter screen provided on the indoor side for filtering the air input from the outdoor side into the indoor side; A first temperature sensor for collecting the inlet temperature of the evaporator; A second temperature sensor for collecting the outlet temperature of the evaporator; A third temperature sensor for collecting the air outlet temperature of the air conditioner; A fourth temperature sensor for collecting the air inlet temperature of the air conditioner; A speed sensor for collecting the air outlet speed of the air conditioner; The controller is configured to: Determine the current operating condition of the air conditioner; Obtain the inlet temperature and outlet temperature of the evaporator, the air outlet speed of the air conditioner, the air outlet temperature and air inlet temperature of the air conditioner; Obtain a first temperature difference based on the inlet temperature and the outlet temperature; Determine the fouling position of the air conditioner under the current operating condition based on the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature; If it is determined that the fouling position is filter screen fouling, control the air conditioner to execute the filter screen self-cleaning mode; If it is determined that the fouling position is heat exchanger fouling, control the air conditioner to execute the heat exchanger self-cleaning mode; Wherein, when determining the fouling position of the air conditioner under the current operating condition based on the first temperature difference, the air outlet speed, the air outlet temperature, and the air inlet temperature, the controller is specifically configured to: Under the refrigeration condition of the air conditioner, obtain a first preset temperature difference, a first preset air outlet speed, a first preset temperature, and a second preset temperature; If it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is lower than the first preset temperature, then determine that the fouling position is filter screen fouling; If it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is higher than the second preset temperature, then determine that the fouling position is heat exchanger fouling; Wherein, the second preset temperature is greater than the first preset temperature; Under the heating condition of the air conditioner, obtain a third preset temperature difference, a second preset air outlet speed, a third preset temperature, and a fourth preset temperature; If it is determined that the first temperature difference is lower than the third preset temperature difference, the air outlet speed is lower than the second preset air outlet speed, and the air outlet temperature is higher than the third preset temperature, then determine that the fouling position is filter screen fouling; If it is determined that the first temperature difference is lower than the third preset temperature difference, the air outlet speed is lower than the second preset air outlet speed, and the air outlet temperature is lower than the fourth preset temperature, then determine that the fouling position is heat exchanger fouling; Wherein, the third preset temperature is greater than the fourth preset temperature.

2. The air conditioner according to claim 1, characterized in that, The controller is further configured to: If it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is between the first preset temperature and the second preset temperature, then control the air conditioner to continue operating in the refrigeration mode; Alternatively, obtain a second temperature difference based on the air outlet temperature and the air inlet temperature; If it is determined that the first temperature difference is higher than the first preset temperature difference, the air outlet speed is higher than the first preset air outlet speed, and the second temperature difference is higher than the second preset temperature difference, then control the air conditioner to continue operating in the refrigeration mode.

3. The air conditioner according to claim 1 or 2, characterized in that, When obtaining the first preset temperature difference, the first preset air outlet speed, the first preset temperature, and the second preset temperature, the controller is specifically configured to: Obtain the operating duration of the air conditioner, the indoor fan speed, the indoor coil temperature, and the working environment humidity; Determine the condensation state of the evaporator based on the operating duration, the air inlet temperature, and the working environment humidity; Determine the first preset air outlet speed when the air conditioner is in a clean state based on the condensation state and the indoor fan speed; Obtain the first preset air outlet temperature when the air conditioner is in a clean state based on the indoor coil temperature, the air inlet temperature, the indoor fan speed, and the condensation state; Use the difference between the first preset air outlet temperature and the first allowable temperature error as the first preset temperature; Use the sum of the first preset air outlet temperature and the first allowable temperature error as the second preset temperature; Determine the first preset temperature difference when the air conditioner is in a clean state based on the outlet temperature and the inlet temperature.

4. The air conditioner according to claim 1, wherein The controller is further configured to: If it is determined that the first temperature difference is lower than the third preset temperature difference, the air outlet speed is lower than the second preset air outlet speed, and the air outlet temperature is between the fourth preset temperature and the third preset temperature, then control the air conditioner to continue operating in the heating mode. Alternatively, obtain a second temperature difference based on the air outlet temperature and the air inlet temperature; If it is determined that the first temperature difference is higher than the third preset temperature difference, the air outlet speed is higher than the second preset air outlet speed, and the second temperature difference is higher than the fourth preset temperature difference, then control the air conditioner to continue operating in the heating mode.

5. The air conditioner according to claim 1 or 4, characterized in that, When obtaining the third preset temperature difference, the second preset air outlet speed, the third preset temperature, and the fourth preset temperature, the controller is specifically configured to: Obtain the indoor fan speed and the indoor coil temperature of the air conditioner; Determine the second preset air outlet speed when the air conditioner is in a clean state based on the indoor fan speed; Obtain the second preset air outlet temperature when the air conditioner is in a clean state based on the indoor coil temperature, the air inlet temperature, and the indoor fan speed; Use the sum of the second preset air outlet temperature and the second allowable temperature error as the third preset temperature; Use the difference between the second preset air outlet temperature and the second allowable temperature error as the fourth preset temperature; Determine the third preset temperature difference when the air conditioner is in a clean state based on the outlet temperature and the inlet temperature.

6. A self-cleaning control method for an air conditioner, characterized in that, Including: Determine the current operating condition of the air conditioner; Obtain the inlet temperature and outlet temperature of the evaporator, obtain the air outlet speed of the air conditioner, and obtain the air outlet temperature and air inlet temperature of the air conditioner; Obtain a first temperature difference based on the inlet temperature and the outlet temperature; Determine the fouling position of the air conditioner under the current operating condition according to the first temperature difference, the air outlet speed, the air outlet temperature and the air inlet temperature; If it is determined that the fouling position is the filter fouling, control the air conditioner to execute the filter self-cleaning mode; If it is determined that the fouling position is the heat exchanger fouling, control the air conditioner to execute the heat exchanger self-cleaning mode.

7. The self-cleaning control method of the air conditioner according to claim 6, characterized in that, Determining the fouling position of the air conditioner under the current operating condition according to the first temperature difference, the air outlet speed, the air outlet temperature and the air inlet temperature includes: Under the refrigeration condition of the air conditioner, obtain a first preset temperature difference, a first preset air outlet speed, a first preset temperature and a second preset temperature; If it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is lower than the first preset temperature, then determine that the fouling position is the filter fouling; If it is determined that the first temperature difference is lower than the first preset temperature difference, the air outlet speed is lower than the first preset air outlet speed, and the air outlet temperature is higher than the second preset temperature, then determine that the fouling position is the heat exchanger fouling; Wherein, the second preset temperature is greater than the first preset temperature.

8. The self-cleaning control method of the air conditioner according to claim 6, characterized in that, Determining the fouling position of the air conditioner under the current operating condition according to the first temperature difference, the air outlet speed, the air outlet temperature and the air inlet temperature includes: Under the heating condition of the air conditioner, obtain a third preset temperature difference, a second preset air outlet speed, a third preset temperature and a fourth preset temperature; If it is determined that the first temperature difference is lower than the third preset temperature difference, the air outlet speed is lower than the second preset air outlet speed, and the air outlet temperature is higher than the third preset temperature, then determine that the fouling position is the filter fouling; If it is determined that the first temperature difference is lower than the third preset temperature difference, the air outlet speed is lower than the second preset air outlet speed, and the air outlet temperature is lower than the fourth preset temperature, then determine that the fouling position is the heat exchanger fouling; Wherein, the third preset temperature is greater than the fourth preset temperature.

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