Air outlet temperature control system and control method of three-control internal machine

Abstract

The application relates to an air outlet temperature control system and a control method of a three-pipe indoor unit, the system comprising a heat exchange pipeline, a temperature detection module and a control module, wherein: the heat exchange pipeline comprises a main heat exchanger, an auxiliary heat exchanger and a first electronic expansion valve, the first electronic expansion valve is used for controlling the flow of high-temperature gaseous refrigerant flowing through the auxiliary heat exchanger; the temperature detection module is used for detecting the air outlet temperature of the air conditioner; the control module is connected with the first electronic expansion valve and the temperature detection module, and the control module is used for controlling the opening degree of the first electronic expansion valve according to the air outlet temperature; wherein, in the case that the air outlet temperature is greater than or equal to a temperature threshold, the control module controls the opening degree of the first electronic expansion valve to increase or decrease, so that the air outlet temperature is less than the temperature threshold. Through the technical scheme provided by the application, the problem that the actual temperature of the air outlet of the air conditioner does not conform to the preset temperature when the air conditioner adopting the three-pipe indoor unit is used for refrigeration is solved.

Description

Technical Field

[0001] The present application relates to the technical field of air conditioners, and in particular to an air outlet temperature control system and a control method for a three-pipe indoor unit. Background Art

[0002] Air conditioners with three-pipe indoor units can achieve constant temperature dehumidification. When a three-pipe indoor unit is set for dehumidification, low-temperature liquid refrigerant flows through the primary heat exchanger, while high-temperature gaseous refrigerant flows through the secondary heat exchanger. The airflow first passes through the primary heat exchanger, where moisture condenses, lowering the temperature of the airflow. The airflow then passes through the secondary heat exchanger, where the dehumidified airflow exchanges heat with the secondary heat exchanger, causing a slight increase in temperature.

[0003] It can be seen that through the three-pipe indoor unit, the air conditioner can ensure that the air outlet temperature of the air conditioner after dehumidification will not change significantly when dehumidifying.

[0004] However, when a user sets an air conditioner with a three-pipe indoor unit for cooling, the high-temperature gaseous refrigerant accumulates in the secondary heat exchanger. This causes the air outlet, cooled by the primary heat exchanger, to be reheated, causing the actual outlet air temperature to rise by 3-5°C compared to the preset temperature. Consequently, when a three-pipe indoor unit is used for cooling, the actual outlet air temperature may not match the preset temperature. Summary of the Invention

[0005] The present application provides an air outlet temperature control system and control method for a three-pipe indoor unit to solve the technical problem that the actual air outlet temperature of an air conditioner using a three-pipe indoor unit does not match the preset temperature when the air conditioner is cooling.

[0006] In a first aspect, the present application provides a three-pipe indoor unit air outlet temperature control system, the system comprising a heat exchange pipe, a temperature detection module, and a control module, wherein:

[0007] The heat exchange pipeline includes a main heat exchanger, an auxiliary heat exchanger and a first electronic expansion valve. The main heat exchanger is arranged near the air inlet, and the auxiliary heat exchanger is arranged near the air outlet. The air outlet of the air conditioner passes through the main heat exchanger and the auxiliary heat exchanger in sequence from the air inlet and is discharged from the air outlet; the low-temperature liquid refrigerant flows into the main heat exchanger from the first refrigerant inlet and flows out of the main heat exchanger from the first refrigerant outlet, and the high-temperature gaseous refrigerant flows into the auxiliary heat exchanger from the second refrigerant inlet and flows out of the auxiliary heat exchanger from the second refrigerant outlet. The second refrigerant outlet is connected to the first refrigerant inlet. The first electronic expansion valve is arranged between the second refrigerant outlet and the first refrigerant inlet. The first electronic expansion valve is used to control the flow rate of the high-temperature gaseous refrigerant flowing through the auxiliary heat exchanger;

[0008] The temperature detection module is arranged between the air outlet and the auxiliary heat exchanger, and is used to detect the outlet temperature of the air from the air conditioner;

[0009] The control module is connected to the first electronic expansion valve and the temperature detection module respectively, and the control module is used to control the opening of the first electronic expansion valve according to the outlet air temperature detected by the temperature detection module; wherein, when the outlet air temperature is greater than or equal to a temperature threshold, the control module controls the opening of the first electronic expansion valve to increase or decrease so that the outlet air temperature is less than the temperature threshold.

[0010] In a feasible embodiment of the present application, the temperature detection module includes:

[0011] an outlet air temperature detection unit, the outlet air temperature detection unit being used to detect the outlet air temperature of the air discharged by the air conditioner;

[0012] The ambient temperature detection unit is used to detect the ambient temperature.

[0013] In a feasible embodiment of the present application, the control module includes:

[0014] an acquisition unit, configured to acquire the air outlet temperature and the ambient temperature;

[0015] a determining unit, configured to determine the temperature threshold according to the ambient temperature in response to a cooling operation instruction;

[0016] A control unit is used to cycle through multiple control cycles to keep the air outlet temperature lower than the temperature threshold; wherein, within any one of the control cycles, when the air outlet temperature is greater than or equal to the temperature threshold, the control module controls the opening of the first electronic expansion valve to increase or decrease.

[0017] In a feasible embodiment of the present application, the determining unit includes:

[0018] A first acquiring subunit, configured to acquire the ambient temperature;

[0019] The first determining subunit is configured to determine the temperature threshold according to the ambient temperature and a preset ambient temperature-temperature threshold mapping table; wherein the ambient temperature and the temperature threshold are positively correlated.

[0020] In a feasible embodiment of the present application, the control unit includes:

[0021] a second determining subunit, configured to determine an initial opening of the first electronic expansion valve at the beginning of any control cycle;

[0022] The first control subunit is used to control the opening of the first electronic expansion valve to increase when the initial opening of the first electronic expansion valve in the current control cycle is 0 and the air outlet temperature is greater than or equal to the temperature threshold, until the air outlet temperature is less than the temperature threshold, and then stop increasing the opening of the first electronic expansion valve.

[0023] In a feasible embodiment of the present application, the control unit further includes:

[0024] The second control subunit is used to control the opening of the first electronic expansion valve to decrease when the initial opening of the first electronic expansion valve in the current control cycle is not 0 and when the air outlet temperature is greater than or equal to the temperature threshold, until the air outlet temperature is less than the temperature threshold, and then stop reducing the opening of the first electronic expansion valve.

[0025] In a feasible embodiment of the present application, the heat exchange pipeline also includes a second electronic expansion valve, which is arranged between the connection between the second refrigerant outlet and the first refrigerant inlet and the main heat exchanger, and the second electronic expansion valve is connected to the control module. The second electronic expansion valve is used to control the flow of low-temperature liquid refrigerant flowing through the main heat exchanger.

[0026] In a second aspect, the present application provides a method for controlling the air outlet temperature of a three-pipe indoor unit. The method is applied to the air outlet temperature control system of the three-pipe indoor unit described in any embodiment of the first aspect above. The method includes:

[0027] In response to a cooling operation instruction, obtaining an air outlet temperature of air from the air conditioner and an ambient temperature;

[0028] determining a temperature threshold according to the ambient temperature;

[0029] Multiple control cycles are cycled to keep the air outlet temperature lower than the temperature threshold; wherein, in any one of the control cycles, when the air outlet temperature is greater than or equal to the temperature threshold, the opening of the first electronic expansion valve is controlled to increase or decrease.

[0030] In a feasible embodiment of the present application, a plurality of control cycles are cyclically performed to maintain the outlet air temperature below the temperature threshold, including:

[0031] At the beginning of any control cycle, determining the initial opening of the first electronic expansion valve;

[0032] When the initial opening of the first electronic expansion valve in the current control cycle is 0, when the outlet air temperature is greater than or equal to the temperature threshold, the opening of the first electronic expansion valve is controlled to increase until the outlet air temperature is less than the temperature threshold, and the increase in the opening of the first electronic expansion valve is stopped.

[0033] In a feasible embodiment of the present application, a plurality of control cycles are cyclically performed to maintain the outlet air temperature below the temperature threshold, further comprising:

[0034] In the case that the initial opening of the first electronic expansion valve in the current control cycle is not 0, when the outlet air temperature is greater than or equal to the temperature threshold, the opening of the first electronic expansion valve is controlled to decrease until the outlet air temperature is less than the temperature threshold, and the reduction of the opening of the first electronic expansion valve is stopped.

[0035] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0036] The technical solution provided in the embodiment of the present application is to provide a first electronic expansion valve at the second refrigerant outlet of the auxiliary heat exchanger in the heat exchange pipeline. Based on the control of the opening of the first electronic expansion valve, the flow rate of the high-temperature gaseous refrigerant flowing through the auxiliary heat exchanger is controlled. In the technical solution provided in the present application, the control module can control the opening of the first electronic expansion valve according to the outlet temperature of the air conditioner, and then control the flow rate of the high-temperature gaseous refrigerant flowing through the auxiliary heat exchanger according to the outlet temperature of the air conditioner, so that the influence of the high-temperature gaseous refrigerant in the auxiliary heat exchanger on the temperature of the air conditioner outlet air is reduced, thereby making the outlet temperature of the air conditioner outlet closer to the preset temperature value. The technical solution provided in the present application effectively solves the technical problem that the actual outlet temperature of the air conditioner does not match the preset temperature when the air conditioner adopts a three-pipe indoor unit during cooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0039] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0040] Figure 1 A schematic structural diagram of a three-pipe indoor unit air outlet temperature control system provided in an embodiment of the present application;

[0041] Figure 2 Another structural diagram of a three-pipe indoor unit air outlet temperature control system provided in an embodiment of the present application;

[0042] Figure 3 A flow chart of a method for controlling the air outlet temperature of a three-pipe indoor unit provided in an embodiment of the present application;

[0043] Figure 4 A schematic flow chart of a method for controlling the air outlet temperature of a three-pipe indoor unit provided in an embodiment of the present application for controlling the opening of a first electronic expansion valve within a control cycle. DETAILED DESCRIPTION

[0044] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0045] The following disclosure provides a number of different embodiments or examples for implementing the different structures of the present application. In order to simplify the disclosure of the present application, the components and arrangements of specific examples are described below. Of course, they are merely examples and the purpose is not to limit the present application. In addition, reference numerals and / or letters can be repeated in different examples of the present application. Such repetition is for the purpose of simplification and clarity, and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0046] In order to solve the technical problem that the actual temperature of the air conditioner outlet air does not match the preset temperature when the air conditioner with a three-control indoor unit is in refrigeration, the present application provides an outlet air temperature control system and control method for a three-control indoor unit, which can reduce the influence of high-temperature gaseous refrigerant in the secondary heat exchanger on the temperature of the air conditioner outlet air, so that the outlet air temperature of the air conditioner outlet air is closer to the preset temperature value.

[0047] Figure 1 A structural schematic diagram of an outlet air temperature control system for a three-control indoor unit provided by an embodiment of the present application is shown in Figure 1 The outlet air temperature control system for a three-control indoor unit provided by an embodiment of the present application includes a heat exchange pipeline, a temperature detection module, and a control module, wherein:

[0048] The heat exchange pipeline includes a primary heat exchanger, a secondary heat exchanger, and a first electronic expansion valve. The primary heat exchanger is arranged near the air inlet, the secondary heat exchanger is arranged near the air outlet, and the air conditioner outlet air is discharged from the air outlet after passing through the primary heat exchanger and the secondary heat exchanger in sequence from the air inlet. Low-temperature liquid refrigerant flows into the primary heat exchanger from the first refrigerant inlet and flows out of the primary heat exchanger from the first refrigerant outlet. High-temperature gaseous refrigerant flows into the secondary heat exchanger from the second refrigerant inlet and flows out of the secondary heat exchanger from the second refrigerant outlet. The second refrigerant outlet is connected to the first refrigerant inlet. The first electronic expansion valve is arranged between the second refrigerant outlet and the first refrigerant inlet. The first electronic expansion valve is used to control the flow of high-temperature gaseous refrigerant flowing through the secondary heat exchanger;

[0049] The temperature detection module is arranged between the air outlet and the secondary heat exchanger. The temperature detection module is used to detect the outlet air temperature of the air conditioner outlet air;

[0050] The control module is connected to the first electronic expansion valve and the temperature detection module, respectively. The control module is used to control the opening degree of the first electronic expansion valve according to the outlet air temperature detected by the temperature detection module. In the case where the outlet air temperature is greater than or equal to the temperature threshold value, the control module controls the opening degree of the first electronic expansion valve to increase or decrease, so that the outlet air temperature is less than the temperature threshold value.

[0051] Specifically, as Figure 1As shown, when the air conditioner starts running, the refrigerant flows in the heat exchange pipeline, and the air outlet of the air conditioner blows from the air inlet to the heat exchange pipeline, passes through the main heat exchanger and the auxiliary heat exchanger in turn, and is blown out from the air outlet to deliver air to the environment where the air conditioner is installed.

[0052] Low-temperature liquid refrigerant flows in the main heat exchanger. The low-temperature liquid refrigerant flows into the main heat exchanger from the first refrigerant inlet and flows out of the main heat exchanger from the first refrigerant outlet. When the air outlet of the air conditioner blows to the main heat exchanger, heat exchange occurs, and the temperature of the air outlet of the air conditioner decreases; high-temperature gaseous refrigerant flows in the auxiliary heat exchanger. The high-temperature gaseous refrigerant flows into the auxiliary heat exchanger from the second refrigerant inlet and flows out of the auxiliary heat exchanger from the second refrigerant outlet. When the air outlet of the air conditioner blows to the auxiliary heat exchanger, heat exchange occurs, and the temperature of the air outlet of the air conditioner increases.

[0053] The second refrigerant outlet is connected to the first refrigerant inlet. When the high-temperature gaseous refrigerant completes heat exchange with the air outlet of the air conditioner, it is converted into low-temperature liquid refrigerant. The low-temperature liquid refrigerant merges with the low-temperature liquid refrigerant in the main heat exchanger and flows out of the main heat exchanger.

[0054] A first electronic expansion valve is provided between the second refrigerant outlet and the first refrigerant inlet. The opening of the first electronic expansion valve can be controlled. By controlling the opening of the first electronic expansion valve, the flow of the high-temperature gaseous refrigerant flowing through the auxiliary heat exchanger can be controlled.

[0055] The control module is connected to the first electronic expansion valve and the temperature detection module, respectively. After obtaining the outlet temperature of the air conditioner, the temperature detection module transmits the outlet temperature to the control module. The control module controls the opening of the first electronic expansion valve based on the outlet temperature, thereby controlling the flow of high-temperature gaseous refrigerant through the auxiliary heat exchanger, and further controlling the heat exchange rate between the auxiliary heat exchanger and the air conditioner outlet. In the technical solution provided in this application, when the outlet temperature is greater than or equal to a temperature threshold, the control module controls the opening of the first electronic expansion valve to increase or decrease so that the outlet temperature of the air conditioner can remain below the temperature threshold.

[0056] In a feasible embodiment of the present application, the temperature detection module includes:

[0057] The air outlet temperature detection unit is used to detect the air outlet temperature of the air conditioner;

[0058] The ambient temperature detection unit is used to detect the ambient temperature.

[0059] Specifically, the outlet air temperature detection unit is directly disposed facing the air outlet, and the outlet air temperature detection unit can be a temperature sensing package for detecting the outlet air temperature of the air conditioner. The probe of the ambient temperature detection unit can extend to the outside of the air conditioner, and the ambient temperature detection unit is used to detect the ambient temperature of the environment in which the air conditioner is currently located.

[0060] It can be understood that if it is desired that the air conditioner does not increase the outlet air temperature of the air conditioner due to the heating of the sub heat exchanger when the air conditioner is in the refrigeration mode, the first electronic expansion valve cannot be directly controlled to be closed. Since the refrigerant circulation system inside the air conditioner is fixed to deliver high-temperature gaseous refrigerant to the sub heat exchanger, if the first electronic expansion valve is completely closed, the refrigerant does not flow, the high-temperature gaseous refrigerant will gradually cool into low-temperature liquid refrigerant, and accumulate in the sub heat exchanger, so that the flow of low-temperature liquid refrigerant in the main heat exchanger is reduced, and the outlet air temperature of the air conditioner is also increased.

[0061] In order to ensure that the outlet air temperature of the air conditioner is close to the preset temperature value, and does not overheat due to the heating of the sub heat exchanger, and does not overheat due to the poor heat exchange effect of the refrigerant accumulated in the main heat exchanger, the flow of high-temperature gaseous refrigerant in the sub heat exchanger needs to be appropriately controlled.

[0062] In a feasible embodiment of the present application, the control module comprises:

[0063] The acquisition unit is configured to acquire the outlet air temperature and the ambient temperature.

[0064] The determination unit is configured to determine a temperature threshold according to the ambient temperature in response to a refrigeration operation instruction.

[0065] The control unit is configured to cyclically perform a plurality of control periods to keep the outlet air temperature less than the temperature threshold, and wherein in any one control period, when the outlet air temperature is greater than or equal to the temperature threshold, the control module controls the opening degree of the first electronic expansion valve to increase or decrease.

[0066] Specifically, after the air conditioner is powered on and runs, the temperature detection module continuously acquires the outlet air temperature and the ambient temperature, and transmits the outlet air temperature and the ambient temperature to the control module; when the control module receives a refrigeration operation instruction, the air conditioner enters the refrigeration mode, and the control module first determines the corresponding temperature threshold according to the ambient temperature. In a feasible embodiment of the present application, the refrigeration operation instruction can be an instruction input by a user through an air conditioner wire controller, and the refrigeration operation instruction is used to instruct the control module to control the air conditioner to enter the refrigeration mode; when the air conditioner is in the refrigeration mode, the control module cyclically performs a plurality of control periods, and controls the opening degree of the first electronic expansion valve in each control period, so that the outlet air temperature of the air conditioner in any one control period is less than the temperature threshold.

[0067] In a feasible embodiment of the present application, the determination unit comprises:

[0068] The first acquisition subunit is configured to acquire the ambient temperature.

[0069] The first determining subunit is configured to determine the temperature threshold according to the ambient temperature and a preset ambient temperature-temperature threshold mapping table, wherein the ambient temperature and the temperature threshold are in a positive correlation.

[0070] Specifically, in order to accurately control the outlet temperature of the air conditioner, so that the outlet air of the air conditioner matches the indoor environment, the temperature threshold is set based on the ambient temperature. In the above embodiment, the ambient temperature-temperature threshold mapping table is preset in the memory of the control module, and the ambient temperature-temperature threshold mapping table is measured by a technician in advance. When the ambient temperature is determined, the corresponding temperature threshold can be found in the ambient temperature-temperature threshold mapping table.

[0071] The ambient temperature and the temperature threshold are in a positive correlation, that is, the higher the ambient temperature, the higher the temperature threshold that can be set, and the higher the outlet temperature of the outlet air of the air conditioner that can be tolerated, and the lower the ambient temperature, the lower the temperature threshold that can be set, and the lower the outlet temperature of the outlet air of the air conditioner that can be tolerated. The reason for such setting is that the ambient temperature limits the heat exchange amount between the high-temperature gas refrigerant in the sub-cooler and the environment. The higher the ambient temperature, the higher the heat exchange cost. In order to ensure the stability of the refrigerant circulation system of the air conditioner, the ambient temperature and the temperature threshold are in a positive correlation.

[0072] In a preferred embodiment of the present application, when the ambient temperature is greater than or equal to 32℃, the temperature threshold is 18℃-20℃; when the ambient temperature is 27℃-32℃, the temperature threshold is 16℃-18℃; and when the ambient temperature is less than 27℃, the temperature threshold is 14-16℃.

[0073] In a feasible embodiment of the present application, in any control period, the opening control mode of the first electronic expansion valve is determined based on the initial opening value of the first electronic expansion valve in the current control period. In this embodiment, the control unit further comprises:

[0074] The second determining subunit is configured to determine the initial opening of the first electronic expansion valve at the beginning of any control period.

[0075] The first control subunit is configured to, when the initial opening of the first electronic expansion valve in the current control period is 0, control the opening of the first electronic expansion valve to increase until the outlet temperature is less than the temperature threshold, and stop increasing the opening of the first electronic expansion valve, when the outlet temperature is greater than or equal to the temperature threshold.

[0076] The second control subunit is configured to, when the initial opening of the first electronic expansion valve in the current control period is not 0, control the opening of the first electronic expansion valve to decrease until the outlet temperature is less than the temperature threshold, and stop decreasing the opening of the first electronic expansion valve, when the outlet temperature is greater than or equal to the temperature threshold.

[0077] Specifically, the control module controls the opening degree of the first electronic expansion valve according to a control period. When entering any control period, the control module first reads the initial opening degree of the first electronic expansion valve. In the case that the initial opening degree of the first electronic expansion valve in the current control period is 0, the opening degree of the first electronic expansion valve is controlled by the first control subunit. In the case that the initial opening degree of the first electronic expansion valve in the current control period is not 0, the opening degree of the first electronic expansion valve is controlled by the second control subunit.

[0078] In a feasible embodiment of the present application, the control period lasts for 30 minutes, and the control module detects the initial opening degree of the first electronic expansion valve once every 30 minutes. Different control processes are performed for different initial opening degrees.

[0079] In the case that the initial opening degree of the first electronic expansion valve in the current control period is 0, it indicates that the high-temperature gaseous refrigerant in the sub-cooler does not flow at this time, and the low-temperature liquid refrigerant obtained by condensing the high-temperature gaseous refrigerant also does not flow to the main heat exchanger. At this time, the air outlet temperature of the air conditioner is compared with the temperature threshold value determined previously. When the air outlet temperature is greater than or equal to the temperature threshold value, the opening degree of the first electronic expansion valve is controlled to increase, the flow of the low-temperature liquid refrigerant in the main heat exchanger is increased, so that the air outlet temperature of the air conditioner is reduced. When the air outlet temperature of the air conditioner is reduced to below the temperature threshold value, the current opening degree is maintained, and the opening degree of the first electronic expansion valve is no longer controlled to continue to increase.

[0080] In the case that the initial opening degree of the first electronic expansion valve in the current control period is not 0, it indicates that the high-temperature gaseous refrigerant in the sub-cooler flows at this time, and the sub-cooler heats the air outlet of the air conditioner. At this time, the air outlet temperature of the air conditioner is compared with the temperature threshold value determined previously. When the air outlet temperature is greater than or equal to the temperature threshold value, the opening degree of the first electronic expansion valve is controlled to decrease, the flow of the high-temperature gaseous refrigerant in the sub-cooler is reduced, so that the air outlet temperature of the air conditioner is reduced. When the air outlet temperature of the air conditioner is reduced to below the temperature threshold value, the current opening degree is maintained, and the opening degree of the first electronic expansion valve is no longer controlled to continue to decrease.

[0081] It can be seen that for control periods with different initial opening degrees, the opening degree of the first electronic expansion valve is always maintained at a relatively appropriate opening degree, which on the one hand ensures that the sub-cooler does not excessively heat the air outlet of the air conditioner, and on the other hand ensures that the main heat exchanger can effectively cool the air outlet of the air conditioner.

[0082] In a feasible embodiment of the present application, the first control subunit can be further configured to:

[0083] Compare the temperature threshold with the outlet air temperature; when the outlet air temperature is greater than or equal to the temperature threshold within a preset time period, increase the opening of the first electronic expansion valve by a preset number of steps; when the outlet air temperature is less than the temperature threshold within a preset time period, maintain the current opening of the first electronic expansion valve.

[0084] For example, if the preset time period is 2 minutes, the preset number of steps is 5 pls, and the control cycle lasts 30 minutes, then during the control cycle, if the outlet air temperature is greater than or equal to the temperature threshold, the number of steps of the first electronic expansion valve will increase by 5 pls every 30 seconds, and the timing will restart after each increase. If the outlet air temperature is less than the temperature threshold within 2 minutes, the number of steps of the first electronic expansion valve will be maintained and will not be increased again until the outlet air temperature is greater than or equal to the temperature threshold again.

[0085] In a feasible embodiment of the present application, the second control subunit may be further configured. In this embodiment, the second control subunit is further configured to:

[0086] Compare the temperature threshold with the outlet air temperature; when the outlet air temperature is greater than or equal to the temperature threshold within a preset time period, reduce the opening of the first electronic expansion valve by a preset number of steps; when the outlet air temperature is less than the temperature threshold within a preset time period, maintain the current opening of the first electronic expansion valve.

[0087] Figure 2 Another structural diagram of a three-pipe indoor unit air outlet temperature control system provided in the embodiment of the present application, referring to Figure 2 The embodiment of the present application provides a three-pipe indoor unit air outlet temperature control system further comprising a second electronic expansion valve, wherein:

[0088] The second electronic expansion valve is arranged between the connection between the second refrigerant outlet and the first refrigerant inlet and the main heat exchanger. The second electronic expansion valve is connected to the control module. The second electronic expansion valve is used to control the flow of low-temperature liquid refrigerant flowing through the main heat exchanger.

[0089] Specifically, the second electronic expansion valve controls the flow of low-temperature liquid refrigerant through the main heat exchanger, thereby controlling the heat exchange between the main heat exchanger and the air conditioner's outlet air. Based on this, the control module can control the opening of the second electronic expansion valve to further control the air conditioner's outlet air temperature.

[0090] Continue to refer to Figure 2In one feasible embodiment of the present application, the outlet air temperature control system of the three-pipe indoor unit further includes a first outlet pipe temperature sensor T1, a second outlet pipe temperature sensor T4, a first inlet pipe temperature sensor T2, and a second inlet pipe temperature sensor T3. These outlet pipe temperature sensors and inlet pipe temperature sensors are capable of real-time detection of the temperature of the refrigerant flowing through the three-pipe indoor unit. The first outlet pipe temperature sensor T1, the second outlet pipe temperature sensor T4, the first inlet pipe temperature sensor T2, and the second inlet pipe temperature sensor T3 are all connected to a control module. The control module can more accurately control the opening of the first and second electronic expansion valves based on the refrigerant temperatures detected by these outlet pipe temperature sensors and inlet pipe temperature sensors.

[0091] The technical solution provided in the embodiment of the present application is to provide a first electronic expansion valve at the second refrigerant outlet of the auxiliary heat exchanger in the heat exchange pipeline. Based on the control of the opening of the first electronic expansion valve, the flow rate of the high-temperature gaseous refrigerant flowing through the auxiliary heat exchanger is controlled. In the technical solution provided in the present application, the control module can control the opening of the first electronic expansion valve according to the outlet temperature of the air conditioner, and then control the flow rate of the high-temperature gaseous refrigerant flowing through the auxiliary heat exchanger according to the outlet temperature of the air conditioner, so that the influence of the high-temperature gaseous refrigerant in the auxiliary heat exchanger on the temperature of the air conditioner outlet air is reduced, thereby making the outlet temperature of the air conditioner outlet closer to the preset temperature value. The technical solution provided in the present application effectively solves the technical problem that the actual outlet temperature of the air conditioner does not match the preset temperature when the air conditioner adopts a three-pipe indoor unit during cooling.

[0092] Figure 3 A flow chart of a method for controlling the air outlet temperature of a three-pipe indoor unit provided in an embodiment of the present application, referring to Figure 3 The present application also provides a method for controlling the air outlet temperature of a three-pipe indoor unit. The method is applied to a three-pipe indoor unit air outlet temperature control system described in any of the above system embodiments. The method can be specifically applied to a control module of the three-pipe indoor unit air outlet temperature control system. The method specifically includes the following steps:

[0093] S31: In response to a cooling operation instruction, obtaining an air outlet temperature of the air conditioner and an ambient temperature;

[0094] S32: Determine a temperature threshold according to the ambient temperature;

[0095] S33: looping through multiple control cycles to keep the outlet air temperature below the temperature threshold; wherein, in any control cycle, when the outlet air temperature is greater than or equal to the temperature threshold, controlling the opening of the first electronic expansion valve to increase or decrease.

[0096] Reference Figure 4In a feasible embodiment of the present application, in step S3, within any control cycle, the method for controlling the opening of the first electronic expansion valve is as follows:

[0097] S41: At the beginning of any control cycle, determining the initial opening of the first electronic expansion valve;

[0098] S42: Determine whether the initial opening of the first electronic expansion valve is 0;

[0099] S43: When the initial opening of the first electronic expansion valve is 0 in the current control cycle and the outlet air temperature is greater than or equal to the temperature threshold, controlling the opening of the first electronic expansion valve to increase until the outlet air temperature is less than the temperature threshold, and then stopping increasing the opening of the first electronic expansion valve;

[0100] S44: In the case that the initial opening of the first electronic expansion valve in the current control period is not 0, when the outlet air temperature is greater than or equal to the temperature threshold, the opening of the first electronic expansion valve is controlled to decrease until the outlet air temperature is less than the temperature threshold, and the reduction of the opening of the first electronic expansion valve is stopped.

[0101] It can be seen that when the initial opening of the first electronic expansion valve is 0 or not 0, different control processes are used to control the opening of the first electronic expansion valve. The reasons for using different control processes have been explained in the above system embodiments and will not be repeated here.

[0102] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0103] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A three-pipe indoor unit air outlet temperature control system, characterized in that: The system includes a heat exchange pipeline, a temperature detection module and a control module, wherein: The heat exchange pipeline includes a main heat exchanger, an auxiliary heat exchanger and a first electronic expansion valve. The main heat exchanger is arranged near the air inlet, and the auxiliary heat exchanger is arranged near the air outlet. The air outlet of the air conditioner passes through the main heat exchanger and the auxiliary heat exchanger in sequence from the air inlet and is discharged from the air outlet; the low-temperature liquid refrigerant flows into the main heat exchanger from the first refrigerant inlet and flows out of the main heat exchanger from the first refrigerant outlet, and the high-temperature gaseous refrigerant flows into the auxiliary heat exchanger from the second refrigerant inlet and flows out of the auxiliary heat exchanger from the second refrigerant outlet. The second refrigerant outlet is connected to the first refrigerant inlet. The first electronic expansion valve is arranged between the connection between the second refrigerant outlet and the first refrigerant inlet and the auxiliary heat exchanger. The first electronic expansion valve is used to control the flow rate of the high-temperature gaseous refrigerant flowing through the auxiliary heat exchanger; The temperature detection module is arranged between the air outlet and the auxiliary heat exchanger, and is used to detect the outlet temperature of the air from the air conditioner; The control module is connected to the first electronic expansion valve and the temperature detection module respectively, and is configured to control the opening of the first electronic expansion valve according to the outlet air temperature detected by the temperature detection module; wherein, when the outlet air temperature is greater than or equal to a temperature threshold, the control module controls the opening of the first electronic expansion valve to increase or decrease so that the outlet air temperature is less than the temperature threshold; Wherein, the temperature detection module includes: an outlet air temperature detection unit, the outlet air temperature detection unit is used to detect the outlet air temperature of the air conditioner; an ambient temperature detection unit, the ambient temperature detection unit is used to detect the ambient temperature; The control module includes: an acquisition unit for acquiring the outlet air temperature and the ambient temperature; a determination unit for determining the temperature threshold according to the ambient temperature in response to a cooling operation instruction; and a control unit for looping through multiple control cycles to keep the outlet air temperature below the temperature threshold; wherein, within any one of the control cycles, when the outlet air temperature is greater than or equal to the temperature threshold, the control module controls the opening of the first electronic expansion valve to increase or decrease; In which, the control unit includes: a second determination subunit, used to determine the initial opening of the first electronic expansion valve at the beginning of any one of the control cycles; a first control subunit, used to control the opening of the first electronic expansion valve to increase when the outlet air temperature is greater than or equal to the temperature threshold when the initial opening of the first electronic expansion valve in the current control cycle is 0, until the outlet air temperature is less than the temperature threshold, and stop increasing the opening of the first electronic expansion valve.

2. The system according to claim 1, wherein: The determining unit includes: A first acquiring subunit, configured to acquire the ambient temperature; The first determining subunit is configured to determine the temperature threshold according to the ambient temperature and a preset ambient temperature-temperature threshold mapping table; wherein the ambient temperature and the temperature threshold are positively correlated.

3. The system according to claim 1, wherein: The control unit further comprises: The second control subunit is used to control the opening of the first electronic expansion valve to decrease when the initial opening of the first electronic expansion valve in the current control cycle is not 0 and when the air outlet temperature is greater than or equal to the temperature threshold, until the air outlet temperature is less than the temperature threshold, and then stop reducing the opening of the first electronic expansion valve.

4. The system according to claim 1, wherein: The heat exchange pipeline also includes a second electronic expansion valve, which is arranged between the connection between the second refrigerant outlet and the first refrigerant inlet and the main heat exchanger. The second electronic expansion valve is connected to the control module. The second electronic expansion valve is used to control the flow of low-temperature liquid refrigerant flowing through the main heat exchanger.

5. A method for controlling the air outlet temperature of a three-pipe indoor unit, characterized in that: The method is applied to the air outlet temperature control system of the three-pipe indoor unit according to any one of claims 1 to 4, and the method comprises: In response to a cooling operation instruction, obtaining an air outlet temperature of air from the air conditioner and an ambient temperature; determining a temperature threshold according to the ambient temperature; Repeating multiple control cycles to maintain the outlet air temperature below the temperature threshold; wherein, in any one of the control cycles, when the outlet air temperature is greater than or equal to the temperature threshold, controlling the opening of the first electronic expansion valve to increase or decrease; Wherein, a plurality of control cycles are circulated to keep the air outlet temperature less than the temperature threshold, including: determining the initial opening of the first electronic expansion valve at the beginning of any one of the control cycles; when the initial opening of the first electronic expansion valve in the current control cycle is 0, when the air outlet temperature is greater than or equal to the temperature threshold, controlling the opening of the first electronic expansion valve to increase until the air outlet temperature is less than the temperature threshold, and stopping increasing the opening of the first electronic expansion valve.

6. The method according to claim 5, characterized in that The method further includes: performing a plurality of control cycles to maintain the air outlet temperature below the temperature threshold; and In the case that the initial opening of the first electronic expansion valve in the current control cycle is not 0, when the outlet air temperature is greater than or equal to the temperature threshold, the opening of the first electronic expansion valve is controlled to decrease until the outlet air temperature is less than the temperature threshold, and the reduction of the opening of the first electronic expansion valve is stopped.

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