Outlet air temperature control system and control method of three-pipe indoor unit

Abstract

The invention relates to an outlet air temperature control system and method for a three-pipe indoor unit, and the system comprises a heat exchange pipeline, a temperature detection module and a control module, and 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 the high-temperature gaseous refrigerant flowing through the auxiliary heat exchanger. The temperature detection module is used for detecting the air outlet temperature of air outlet 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; and under the condition that the air outlet temperature is larger than or equal to the temperature threshold value, the control module controls the opening degree of the first electronic expansion valve to be increased or decreased, so that the air outlet temperature is smaller than the temperature threshold value. Through the technical scheme provided by the invention, the problem that the actual air outlet temperature of the air conditioner does not accord with 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] The air conditioner with three-pipe indoor unit can realize the function of constant temperature dehumidification. When the user sets the air conditioner with three-pipe indoor unit for dehumidification, the main heat exchanger in the three-pipe indoor unit flows low-temperature liquid refrigerant, and the auxiliary heat exchanger flows high-temperature gaseous refrigerant. The air outlet of the air conditioner first passes through the main heat exchanger inside the air conditioner, and the water vapor in the air outlet of the air conditioner condenses on the main heat exchanger. At the same time, the temperature of the air outlet of the air conditioner decreases. The air outlet of the air conditioner then passes through the auxiliary heat exchanger. The air outlet of the air conditioner that has lost water vapor exchanges heat with the auxiliary heat exchanger, and the temperature of the air outlet of the air conditioner increases slightly.

[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 the user sets the air conditioner with a three-pipe indoor unit for cooling, the high-temperature gaseous refrigerant is accumulated in the auxiliary heat exchanger, so the air outlet of the air conditioner after being cooled by the main heat exchanger will be reheated, causing the actual air outlet temperature of the air conditioner to rise by 3-5°C compared to the preset temperature. Therefore, when the air conditioner with a three-pipe indoor unit is cooling, the actual air outlet temperature of the air conditioner will not match the preset temperature. Summary of the invention

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

[0006] In a first aspect, the present application provides an air outlet temperature control system for a three-pipe indoor unit, the system comprising a heat exchange pipeline, 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 the temperature detection module 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 is 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, used to acquire the outlet air 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, in 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 acquisition subunit, used to acquire the ambient temperature;

[0019] The first determination subunit is used to determine the temperature threshold according to the ambient temperature and a preset ambient temperature-temperature threshold mapping table; wherein there is a positive correlation between the ambient temperature and the temperature threshold.

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

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

[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 outlet air temperature is greater than or equal to the temperature threshold, until the outlet air 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 for controlling the opening of the first electronic expansion valve to decrease when the initial opening of the first electronic expansion valve is not 0 in the current control cycle and when the outlet air temperature is greater than or equal to the temperature threshold, until the outlet air temperature is less than the temperature threshold, and then stopping the reduction of 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, and the second electronic expansion valve is used to control the flow rate of low-temperature liquid refrigerant flowing through the main heat exchanger.

[0026] In a second aspect, the present application provides an air outlet temperature control method for a three-pipe indoor unit, the method being applied to the air outlet temperature control system of the three-pipe indoor unit described in any one of the embodiments of the first aspect, the method comprising:

[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 outlet air temperature lower than 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, 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 keep the outlet air temperature lower than the temperature threshold, including:

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

[0032] In the case that 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 cycled to keep the outlet air temperature lower than the temperature threshold, and further includes:

[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 by the embodiment of the present application is to set a first electronic expansion valve at the second refrigerant outlet of the auxiliary heat exchanger in the heat exchange pipeline, and control the flow of the high-temperature gaseous refrigerant flowing through the auxiliary heat exchanger based on the control of the opening of the first electronic expansion valve. In the technical solution provided by 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 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 outlet temperature of the air conditioner is reduced, so that the outlet temperature of the air conditioner is closer to the preset temperature value. The technical solution provided by 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 for 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0039] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

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

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

[0042] Figure 3 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;

[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] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0045] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

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

[0047] Figure 1 A schematic diagram of a structure of a three-pipe indoor unit air outlet temperature control system provided in an embodiment of the present application, referring to Figure 1 The embodiment of the present application provides a three-pipe indoor unit air outlet temperature control system comprising a heat exchange pipeline, a temperature detection module and a control module, wherein:

[0048] 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 of the high-temperature gaseous refrigerant flowing through the auxiliary heat exchanger;

[0049] 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;

[0050] 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 the 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.

[0051] Specifically, Figure 1As shown, when the air conditioner starts to run, 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] A 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. A 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 a 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 the high-temperature gaseous refrigerant flowing through the auxiliary heat exchanger, and further controlling the heat exchange between the auxiliary heat exchanger and the air conditioner outlet. In the technical solution provided by the present application, when the 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, so that the outlet temperature of the air conditioner can be kept lower than the temperature threshold.

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

[0057] The outlet air temperature detection unit is used to detect the outlet air 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 arranged facing the air outlet, and the outlet air temperature detection unit can be a temperature sensing package, which is used to detect 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 current environment of the air conditioner.

[0060] It is understandable that if it is expected that the outlet air temperature of the air conditioner will not increase due to the heating of the auxiliary heat exchanger when the air conditioner is cooling, the first electronic expansion valve cannot be directly controlled to close. Since the refrigerant circulation system inside the air conditioner fixedly transports the high-temperature gaseous refrigerant to the auxiliary heat exchanger, if the first electronic expansion valve is completely closed, the refrigerant will not circulate, and the high-temperature gaseous refrigerant will gradually cool into low-temperature liquid refrigerant and accumulate in the auxiliary heat exchanger, which will reduce the flow of the low-temperature liquid refrigerant in the main heat exchanger and increase the outlet air temperature of the air conditioner.

[0061] In order to ensure that the air outlet temperature of the air conditioner is close to the preset temperature value and will not be overheated due to the heating of the auxiliary heat exchanger or the poor heat exchange effect of the main heat exchanger due to the accumulation of refrigerant, it is necessary to properly control the flow rate of the high-temperature gaseous refrigerant in the auxiliary heat exchanger.

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

[0063] An acquisition unit, used to acquire the outlet air temperature and the ambient temperature;

[0064] a determination unit, configured to determine a temperature threshold value according to an ambient temperature in response to a cooling operation instruction;

[0065] The control unit is used to cycle through multiple control cycles to keep the outlet air temperature lower than a temperature threshold; wherein, in any control cycle, 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.

[0066] Specifically, when the air conditioner is powered on, the temperature detection module continuously obtains 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 the 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 may be an instruction input by the user through the 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 operating in the refrigeration mode, the control module cycles through multiple control cycles, and controls the opening of the first electronic expansion valve in each control cycle, so that the outlet air temperature of the air conditioner in any control cycle is less than the temperature threshold.

[0067] In a feasible embodiment of the present application, the determining unit includes:

[0068] A first acquisition subunit is used to acquire the ambient temperature;

[0069] The first determination subunit is used 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.

[0070] Specifically, in order to achieve accurate control of the air outlet temperature of the air conditioner so that the air outlet 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 pre-measured by a technician. When the ambient temperature is determined, the corresponding temperature threshold can be found in the ambient temperature-temperature threshold mapping table.

[0071] There is a positive correlation between the ambient temperature and the temperature threshold, that is, the higher the ambient temperature, the higher the temperature threshold can be set, and the higher the tolerable air outlet temperature of the air conditioner. The lower the ambient temperature, the lower the temperature threshold can be set, and the lower the tolerable air outlet temperature of the air conditioner. The reason for this setting is that the ambient temperature limits the heat exchange between the high-temperature gas refrigerant in the auxiliary heat exchanger and the environment. The higher the ambient temperature, the higher the heat exchange cost. In order to ensure the stability of the air conditioner refrigerant circulation system, the ambient temperature and the temperature threshold are set to be positively correlated.

[0072] In a preferred embodiment of the present application, when the ambient temperature is ≥32°C, the temperature threshold is 18°C ​​to 20°C; when 27°C ≤ ambient temperature <32°C, the temperature threshold is 16°C to 18°C; when the ambient temperature is <27°C, the temperature threshold is 14 to 16°C.

[0073] In a feasible embodiment of the present application, in any control cycle, 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 cycle. In this embodiment, the control unit further includes:

[0074] A second determining subunit is used to determine the initial opening degree of the first electronic expansion valve at the beginning of any control cycle;

[0075] 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 is 0 in the current control cycle and when the outlet air temperature is greater than or equal to the temperature threshold, until the outlet air temperature is less than the temperature threshold, and then stop increasing the opening of the first electronic expansion valve.

[0076] 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 is not 0 in the current control cycle and when the outlet air temperature is greater than or equal to the temperature threshold, until the outlet air temperature is less than the temperature threshold, and stop reducing the opening of the first electronic expansion valve.

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

[0078] In a feasible embodiment of the present application, the control cycle lasts for 30 minutes, the control module detects the initial opening of the first electronic expansion valve every 30 minutes, and executes different control processes for different initial openings.

[0079] When the initial opening of the first electronic expansion valve in the current control cycle is 0, it means that the high-temperature gaseous refrigerant in the auxiliary heat exchanger does not flow, and the low-temperature liquid refrigerant obtained by condensing the high-temperature gaseous refrigerant will no longer flow to the main heat exchanger. At this time, the air outlet temperature of the air conditioner is compared with the previously determined temperature threshold. 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, and the flow rate 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, the current opening is stopped, and the opening of the first electronic expansion valve is no longer controlled to continue to increase.

[0080] In the case where the initial opening of the first electronic expansion valve in the current control cycle is not 0, it means that the high-temperature gaseous refrigerant in the auxiliary heat exchanger is flowing at this time, and the auxiliary heat exchanger heats the air outlet of the air conditioner. At this time, the air outlet temperature of the air conditioner is compared with the previously determined temperature threshold. 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 decrease, and the flow of the high-temperature gaseous refrigerant in the auxiliary heat exchanger 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, the current opening is stopped, and the opening of the first electronic expansion valve is no longer controlled to continue to decrease.

[0081] It can be seen that for control cycles with different initial openings, the opening of the first electronic expansion valve is always maintained at a relatively appropriate opening, which ensures that the auxiliary heat exchanger will not overheat the air outlet of the air conditioner on the one hand, and ensures that the main heat exchanger can effectively cool the air outlet of the air conditioner on the other hand.

[0082] In a feasible embodiment of the present application, the first control subunit may be further configured. In this embodiment, the first control subunit is 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, the preset time period is set to 2 minutes, the preset number of steps is set to 5 pls, and the control cycle lasts for 30 minutes. 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 is increased by 5 pls every 30 seconds, and the timing is restarted 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 is maintained and no longer increased until the outlet air temperature is greater than or equal to the temperature threshold next time.

[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 schematic diagram of a three-pipe indoor unit air outlet temperature control system provided in an embodiment of the present application, referring to Figure 2 , an air outlet temperature control system of a three-pipe indoor unit provided in an embodiment of the present application further includes 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 can control the flow of low-temperature liquid refrigerant flowing through the main heat exchanger, thereby controlling the heat exchange between the main heat exchanger and the air outlet of the air conditioner. Based on this, the control module can control the opening of the second electronic expansion valve to further control the air outlet temperature of the air conditioner.

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

[0091] The technical solution provided by the embodiment of the present application is to set a first electronic expansion valve at the second refrigerant outlet of the auxiliary heat exchanger in the heat exchange pipeline, and control the flow of the high-temperature gaseous refrigerant flowing through the auxiliary heat exchanger based on the control of the opening of the first electronic expansion valve. In the technical solution provided by 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 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 outlet temperature of the air conditioner is reduced, so that the outlet temperature of the air conditioner is closer to the preset temperature value. The technical solution provided by 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 for 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 embodiment of the present application further provides a method for controlling the air outlet temperature of a three-pipe indoor unit. The method is applied to a control system for the air outlet temperature of a three-pipe indoor unit described in any one of the above system embodiments. The method can be specifically applied to a control module of the air outlet temperature control system of the three-pipe indoor unit. The method specifically includes the following steps:

[0093] S31: In response to a cooling operation instruction, obtaining an air outlet temperature of air from 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 lower than 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, in 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 in the current control cycle is 0, 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 until the outlet air temperature is less than the temperature threshold, and stopping increasing the opening of the first electronic expansion valve;

[0100] S44: When 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.

[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 only for the purpose of describing specific example embodiments 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 "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence 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 interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0103] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. An air outlet temperature control system for a three-pipe indoor unit, 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 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; The temperature detection module is arranged between the air outlet and the auxiliary heat exchanger, and the temperature detection module 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 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.

2. The system according to claim 1, characterized in that The temperature detection module comprises: An outlet air temperature detection unit, the outlet air temperature detection unit is used to detect the outlet air temperature of the air discharged by the air conditioner; The ambient temperature detection unit is used to detect the ambient temperature.

3. The system according to claim 2, characterized in that The control module comprises: An acquisition unit, used to acquire the outlet air temperature and the ambient temperature; a determining unit, configured to determine the temperature threshold according to the ambient temperature in response to a cooling operation instruction; A control unit is used to cycle through multiple control cycles 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 control module controls the opening of the first electronic expansion valve to increase or decrease.

4. The system according to claim 3, characterized in that The determining unit comprises: A first acquisition subunit, used to acquire the ambient temperature; The first determination subunit is used to determine the temperature threshold according to the ambient temperature and a preset ambient temperature-temperature threshold mapping table; wherein there is a positive correlation between the ambient temperature and the temperature threshold.

5. The system according to claim 3, characterized in that The control unit comprises: a second determining subunit, configured to determine an initial opening degree of the first electronic expansion valve at the beginning of any of the control cycles; 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 outlet air temperature is greater than or equal to the temperature threshold, until the outlet air temperature is less than the temperature threshold, and then stop increasing the opening of the first electronic expansion valve.

6. The system according to claim 5, characterized in that The control unit also includes: The second control subunit is used for controlling the opening of the first electronic expansion valve to decrease when the initial opening of the first electronic expansion valve is not 0 in the current control cycle and when the outlet air temperature is greater than or equal to the temperature threshold, until the outlet air temperature is less than the temperature threshold, and then stopping the reduction of the opening of the first electronic expansion valve.

7. The system according to claim 1, characterized in that 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, and the second electronic expansion valve is used to control the flow of low-temperature liquid refrigerant flowing through the main heat exchanger.

8. 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 7, 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; Multiple control cycles are cycled to keep the outlet air temperature lower than 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, the opening of the first electronic expansion valve is controlled to increase or decrease.

9. The method according to claim 8, characterized in that Cycling multiple control cycles to keep the outlet air temperature lower than the temperature threshold includes: At the beginning of any of the control cycles, determining the initial opening of the first electronic expansion valve; In the case that 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.

10. The method according to claim 8, characterized in that Cycling multiple control cycles to keep the outlet air temperature lower than the temperature threshold, further comprising: 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.

Images