Air conditioner and control method thereof

Abstract

The present application relates to air conditioning technical field, specifically provide a kind of air conditioner and its control method, it aims at certain degree to solve the existing air conditioner in the refrigerant is recycled to outdoor heat exchanger, when starting compressor, compressor cannot make air conditioner normal operation problem.The air conditioner of the present application includes first branch and first on-off valve arranged on it, first branch both ends are respectively communicated with outdoor heat exchanger, gas-liquid separator inlet, control method includes: in the case where refrigerant has been recycled to outdoor heat exchanger, selectively make first on-off valve intermittent in open state.This can discharge the refrigerant in outdoor heat exchanger, so that outdoor heat exchanger has some space to receive gaseous refrigerant from compressor outlet after starting compressor and make most of it into normal temperature high pressure liquid refrigerant, avoid because outdoor heat exchanger cannot normally function and lead to air conditioner cannot normal operation, to a certain extent, solve the problem that compressor cannot make air conditioner normal operation.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, specifically providing an air conditioner and its control method. Background Technology

[0002] During the use of an air conditioner, refrigerant leakage in the indoor unit (i.e., the indoor side of the air conditioner) can endanger the health of occupants and may also pose an explosion risk due to increased refrigerant concentration. To address this, those skilled in the art have designed air conditioners to recover refrigerant from the indoor unit to the outdoor unit, preventing further leakage. Specifically, see [link to relevant documentation]. Figure 1 Air conditioner 1 includes an indoor expansion valve 11, an indoor heat exchanger 12, a gas-liquid separator 13, a compressor 14, an outdoor heat exchanger 15, an outdoor expansion valve 16, and a four-way reversing valve 17. Furthermore, an on / off valve 18 is provided between the indoor expansion valve 11 and the outdoor expansion valve 16. Taking heating mode as an example, if refrigerant leakage occurs on the indoor side of air conditioner 1 while it is in heating mode, the state of the four-way reversing valve 17 is switched to allow air conditioner 1 to enter cooling mode (in cooling mode, the refrigerant flow direction is as follows...). Figure 1 As indicated by the middle arrow, and in Figure 1 The dashed lines inside the four-way reversing valve 17 indicate a closed circuit, and the solid lines indicate a closed circuit. When the on / off valve 18 is closed, the compressor 14 continues to operate. In this way, the refrigerant on the indoor side continuously flows into the outdoor heat exchanger 15 under the action of the compressor 14 and is liquefied. Because the on / off valve 18 is closed, and the highest point of the pipe between the inlet of the outdoor heat exchanger 15 and the outlet of the compressor 14 in cooling mode is higher than the liquid level inside the outdoor heat exchanger 15 after refrigerant recovery, the refrigerant cannot flow back into the indoor side. Therefore, the refrigerant is stored in the outdoor heat exchanger 15 after flowing in. After all the refrigerant in the indoor side, the gas-liquid separator 13, and the compressor 14 has entered the outdoor heat exchanger 15, the compressor 14 is turned off, completing the refrigerant recovery. Although this method avoids more refrigerant leakage indoors, after the leak is repaired, when the compressor is started, the refrigerant often has difficulty circulating normally in the refrigerant circulation loop, and the air conditioner cannot operate normally.

[0003] Therefore, there is a need in the field for a new air conditioner and its control method to solve the above problems. Summary of the Invention

[0004] The present invention aims to solve the above-mentioned technical problems, namely, to a certain extent, the problem that the compressor cannot make the air conditioner operate normally when the compressor is started after the refrigerant is recovered to the outdoor heat exchanger.

[0005] In a first aspect, the present invention provides a control method for an air conditioner, characterized in that the air conditioner includes an indoor heat exchanger, a gas-liquid separator, a compressor, and an outdoor heat exchanger connected by pipes to form a refrigerant circulation main loop; the air conditioner further includes a first branch and a first on / off valve disposed on the first branch, a first end of the first branch being connected to the outdoor heat exchanger, and a second end of the first branch being connected to the inlet of the gas-liquid separator, wherein when the first on / off valve is in an open state, refrigerant in the outdoor heat exchanger can flow into the gas-liquid separator; the control method includes: when refrigerant has been recovered into the outdoor heat exchanger, selectively and intermittently opening the first on / off valve so that refrigerant in the outdoor heat exchanger flows into the gas-liquid separator.

[0006] When the above technical solution is adopted, if the refrigerant is recovered to the outdoor side of the air conditioner, when the first on / off valve is opened, the refrigerant can flow out from the outdoor heat exchanger, freeing up some space in the outdoor heat exchanger. In this way, after the compressor is started, the gaseous refrigerant discharged from the compressor outlet can enter the outdoor heat exchanger, so that the outdoor heat exchanger can convert most of it into room temperature high-pressure liquid refrigerant. In other words, the outdoor heat exchanger can function normally at this time, avoiding the air conditioner from failing to operate normally due to the outdoor heat exchanger's inability to function properly.

[0007] In the preferred embodiment of the control method for the air conditioner described above, the step of "selectively keeping the first on / off valve intermittently in the open state" specifically includes: keeping the first on / off valve intermittently in the open state by alternating opening and closing.

[0008] In the preferred embodiment of the control method for the air conditioner described above, the step of "intermittently keeping the first on-off valve in an alternating opening and closing manner" specifically includes: opening the first on-off valve; obtaining the current liquid level of the gas-liquid separator; determining whether the current liquid level has reached a preset liquid level; closing the first on-off valve whenever the current liquid level reaches the preset liquid level, and reopening the first on-off valve when the current liquid level is lower than the preset liquid level; wherein, the preset liquid level does not exceed the highest allowable liquid level in the gas-liquid separator.

[0009] When the above technical solution is adopted, the first on-off valve can be closed when the current liquid level reaches the preset level, promptly stopping the injection of refrigerant into the gas-liquid separator and preventing the refrigerant in the gas-liquid separator from exceeding its maximum allowable level, which could lead to liquid refrigerant entering the compressor and causing liquid slugging. Furthermore, when the current liquid level is lower than the preset level, the first on-off valve can be reopened, allowing refrigerant from the outdoor heat exchanger to continue being injected into the gas-liquid separator, making fuller use of the space in the gas-liquid separator and thus discharging as much refrigerant as possible from the outdoor heat exchanger.

[0010] In a preferred embodiment of the control method for the air conditioner described above, the control method further includes: after each closure of the first on / off valve, obtaining the duration of the closure of the first on / off valve; determining whether the duration has reached a preset duration; if the duration has reached the preset duration, obtaining the current liquid level of the gas-liquid separator again and determining whether the current liquid level has reached the preset liquid level.

[0011] By adopting the above technical solution, the number of times the current liquid level of the gas-liquid separator is obtained is reduced, thereby reducing the workload of the controller and enabling the controller to take on more other control operations.

[0012] In a preferred embodiment of the control method for the air conditioner described above, the air conditioner further includes a second on / off valve disposed between the outdoor heat exchanger and the indoor heat exchanger. When the second on / off valve is in the open state, the refrigerant in the outdoor heat exchanger can flow into the outlet of the compressor. The control method further includes: in the step of "obtaining the current liquid level of the gas-liquid separator again and determining whether the current liquid level has reached the preset liquid level", if it is determined that the current liquid level has reached the preset liquid level, the second on / off valve is opened so that the refrigerant in the outdoor heat exchanger flows into the outlet of the compressor.

[0013] When the above technical solution is adopted, after the second shut-off valve is opened, the refrigerant in the outdoor heat exchanger flows out and through the second shut-off valve, eventually flowing into the compressor. This further increases the amount of refrigerant in the compressor and the pressure at the compressor outlet, thereby helping to raise the compressor outlet pressure to the level required for normal operation and providing a foundation for the compressor to start smoothly in the future.

[0014] In a preferred embodiment of the control method for the air conditioner described above, the control method further includes: obtaining the pressure at the outlet of the compressor when the second on / off valve is in the open state; and selectively starting the compressor according to the pressure.

[0015] With the above technical solution, the compressor outlet pressure can be monitored when the second on / off valve is in the open state, so that the compressor can be started at the appropriate time.

[0016] In the preferred embodiment of the control method for the above-mentioned air conditioner, the step of "selectively starting the compressor according to the pressure" specifically includes: determining whether the pressure is within a preset pressure range; if the pressure is within the preset pressure range, then starting the compressor; wherein the preset pressure range does not exceed the maximum allowable range of the compressor outlet.

[0017] By adopting the above technical solution, the compressor is only started when it is in a normal working state, so that the compressor can start smoothly.

[0018] In the preferred embodiment of the control method for the air conditioner described above, the step of "selectively starting the compressor according to the pressure" further includes: if the pressure exceeds the preset pressure range, then keeping the compressor off.

[0019] By adopting the above technical solution, damage to the compressor caused by starting it under unsuitable conditions can be avoided.

[0020] In a preferred embodiment of the control method for the above-mentioned air conditioner, the control method further includes: during the process of the compressor being in operation to recover refrigerant into the outdoor heat exchanger, the second on / off valve is kept in a closed state.

[0021] When the above technical solution is adopted, the second on-off valve is closed, so that after the refrigerant enters the outdoor heat exchanger, it cannot flow through the second on-off valve and thus cannot return to the indoor side of the air conditioner. This allows the refrigerant to be stored in the outdoor heat exchanger, thereby achieving refrigerant recovery.

[0022] In a second aspect, the present invention also provides an air conditioner, characterized in that the controller of the air conditioner is configured to perform any of the control methods described above. Attached Figure Description

[0023] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0024] Figure 1 This is a schematic diagram of the structure of an air conditioner in the prior art;

[0025] Figure 2 This is a schematic diagram of the structure of an embodiment of the air conditioner of the present invention;

[0026] Figure 3 This is a flowchart of the main steps of the air conditioner control method of the present invention;

[0027] Figure 4 This is a flowchart of one embodiment of the air conditioner control method of the present invention. Figure 1 ;

[0028] Figure 5 This is a flowchart of one embodiment of the air conditioner control method of the present invention. Figure 2 .

[0029] Figure label:

[0030] Air conditioner 1;

[0031] Indoor expansion valve 11; Indoor heat exchanger 12; Gas-liquid separator 13; Compressor 14; Outdoor heat exchanger 15; Outdoor expansion valve 16; Four-way reversing valve 17; On / off valve 18;

[0032] Air conditioner 2;

[0033] Indoor expansion valve 21; Indoor heat exchanger 22; Gas-liquid separator 23; Compressor 24; Outdoor heat exchanger 25; Outdoor expansion valve 26; Four-way reversing valve 27; First on / off valve 28; Second on / off valve 29. Detailed Implementation

[0034] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. For example, although this embodiment is described in conjunction with an air conditioner having a four-way reversing valve, this is not intended to limit the scope of protection of this application. Without departing from the principles of this application, those skilled in the art can apply the control method of this application to air conditioners without a four-way reversing valve.

[0035] It should be noted that in the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0037] First, combine Figure 2The structure of the air conditioner 2 in this invention is described in Figure 2. The air conditioner 2 includes an indoor expansion valve 21, an indoor heat exchanger 22, a gas-liquid separator 23, a compressor 24, an outdoor heat exchanger 25, an outdoor expansion valve 26, and a four-way reversing valve 27, all connected by pipes to form a main refrigerant circulation loop. Both the outdoor expansion valve 26 and the indoor expansion valve 21 can control the refrigerant flow rate by changing their opening degree. The gas-liquid separator 23 is equipped with a level detection device (such as a level sensor) for detecting the refrigerant level within the separator. A pressure detection device (such as a pressure sensor) is also provided at the outlet of the compressor 24 for detecting the outlet pressure of the compressor 24. The air conditioner 2 also includes a first branch and a first on / off valve 28 disposed on the first branch. The first end of the first branch is connected to the outdoor heat exchanger 25, and the second end of the first branch is connected to the inlet of the gas-liquid separator 23. With the first shut-off valve 28 in the open state, the refrigerant in the outdoor heat exchanger 25 can flow into the gas-liquid separator 23. Of course, this requires those skilled in the art to reasonably set the height of the outdoor heat exchanger 25, the gas-liquid separator 23, and the highest point of the passage between them (including the pipeline and the flow path in the first shut-off valve 28): the height of the outdoor heat exchanger 25 and the gas-liquid separator 23 should be set such that the liquid level of the outdoor heat exchanger 25 after refrigerant recovery is higher than the inlet of the gas-liquid separator 23, and the highest point of the passage between the outdoor heat exchanger 25 and the gas-liquid separator 23 is lower than the liquid level of the outdoor heat exchanger 25 after refrigerant recovery (in...). Figure 2 The air conditioner shown is, according to: Figure 2 The outdoor heat exchanger 25 is positioned at the upper open end, i.e., the refrigerant inlet end of the outdoor heat exchanger 25 in cooling mode. The highest point of the pipe between the outdoor heat exchanger 25 and the first end of the first branch, as well as the highest point of the first branch, should be set lower than the liquid level of the outdoor heat exchanger 25 after refrigerant recovery is completed. This ensures that the refrigerant in the outdoor heat exchanger 25 can flow smoothly into the gas-liquid separator 23. The air conditioner 2 also includes a second on / off valve 29 disposed between the outdoor heat exchanger 25 and the indoor expansion valve 21. With the second shut-off valve 29 in the open position, the refrigerant in the outdoor heat exchanger 25 can flow into the outlet of the compressor 24. Of course, this requires those skilled in the art to reasonably set the height positions of the outdoor heat exchanger 25, the compressor 24 outlet, and the highest point of the passage between them (including the pipes and the flow paths in the components on those pipes): the height positions of the outdoor heat exchanger 25 and the compressor 24 outlet should be set such that: the liquid level of the outdoor heat exchanger 25 after refrigerant recovery is completed is higher than the inlet of the compressor 24 outlet, and the highest point of the passage between the opening end of the outdoor heat exchanger 25 furthest from the compressor 24 and the compressor 24 outlet is lower than the liquid level of the outdoor heat exchanger 25 after refrigerant recovery is completed (in...). Figure 2 The air conditioner shown is, according to: Figure 2In the orientation of the outdoor heat exchanger 25, the outdoor heat exchanger 25 is located at the lower opening end, that is, the refrigerant outlet end of the outdoor heat exchanger 25 in the cooling mode. The highest point of the passage between the outdoor heat exchanger 25 and the compressor 24 outlet should be set lower than the liquid level of the outdoor heat exchanger 25 after the refrigerant recovery is completed. In this way, the refrigerant in the outdoor heat exchanger 25 can flow smoothly into the compressor 24 outlet through the second shut-off valve 29.

[0038] As described in the background section, when the air conditioner 2 starts the compressor 24 after recovering the refrigerant to the outdoor heat exchanger 25, the compressor 24 fails to enable the air conditioner 2 to operate normally. To solve this problem, this application proposes a control method for the air conditioner 2, such as... Figure 3 As shown, the control method includes:

[0039] S1. When the refrigerant has been recovered into the outdoor heat exchanger 25, the first on / off valve 28 is selectively opened intermittently so that the refrigerant in the outdoor heat exchanger 25 flows into the gas-liquid separator 23.

[0040] In step S1, the first on-off valve 28 is selectively kept intermittently open. Specifically, this can be done by keeping the first on-off valve 28 open for a period of time, then closing it, and then not opening the first on-off valve 28 again before starting the compressor 24. Alternatively, the first on-off valve 28 can be kept intermittently open in an alternating opening and closing manner. When the first on-off valve 28 is open, refrigerant flows out of the outdoor heat exchanger 25. After the refrigerant flows out, some space is freed up in the outdoor heat exchanger 25. This allows the gaseous refrigerant discharged from the compressor 24 outlet to enter the outdoor heat exchanger 25 after the compressor 24 is started. This allows the outdoor heat exchanger 25 to convert most of the refrigerant into a room-temperature, high-pressure liquid refrigerant. In other words, the outdoor heat exchanger 25 can function normally at this time, and the air conditioner will not malfunction due to the outdoor heat exchanger 25 failing to function properly. Conversely, if the refrigerant does not flow out of the outdoor heat exchanger 25, then the outdoor heat exchanger 25 will be filled with the recovered refrigerant. The outdoor heat exchanger 25 will not have enough space to allow more refrigerant to enter. Therefore, when the compressor 24 starts, the gaseous refrigerant discharged from the compressor 24 outlet cannot enter the outdoor heat exchanger 25. Naturally, the outdoor heat exchanger 25 will not be able to function for the gaseous refrigerant (the outdoor heat exchanger 25 can only function for the refrigerant if it enters the outdoor heat exchanger 25), thus causing the air conditioner to malfunction.

[0041] It should be noted that after repairing the refrigerant leak, when it is necessary to start the compressor, the compressor can be started during or after the execution of the control method of this invention. Of course, the compressor can also be started first, and then the control method of this invention can be started.

[0042] Preferably, the step of "intermittently keeping the first on / off valve 28 in the open state by alternating opening and closing" specifically includes:

[0043] Open the first on / off valve 28;

[0044] Obtain the current liquid level of the gas-liquid separator 23;

[0045] Determine whether the current liquid level has reached the preset liquid level;

[0046] The first on / off valve 28 is closed whenever the current liquid level reaches the preset liquid level, and the first on / off valve 28 is reopened when the current liquid level is lower than the preset liquid level.

[0047] The preset liquid level shall not exceed the highest allowable liquid level within the gas-liquid separator 23.

[0048] Whenever the liquid level reaches the preset level, closing the first on-off valve 28 promptly stops the injection of refrigerant into the gas-liquid separator 23, preventing the refrigerant in the gas-liquid separator 23 from exceeding its maximum allowable level and causing liquid refrigerant to enter the compressor 24, resulting in liquid slugging. The refrigerant entering the gas-liquid separator 23 from the outdoor heat exchanger 25 is in a gas-liquid mixed state. Therefore, the detected liquid level in the gas-liquid separator 23 will be relatively high. Over time, the gaseous refrigerant in the gas-liquid mixed state in the gas-liquid separator 23 rises due to its lower density, while the liquid refrigerant settles due to its higher density. This results in a state of refrigerant gas-liquid separation with the gaseous refrigerant on top and the liquid refrigerant at the bottom. At this point, the detected liquid level will be lower than the preset level. Reopening the first on-off valve 28 allows the refrigerant in the outdoor heat exchanger 25 to continue being injected into the gas-liquid separator 23, making fuller use of the space in the gas-liquid separator 23, and also allowing as much refrigerant as possible to be discharged from the outdoor heat exchanger 25.

[0049] In some alternative implementations, the number of times the first on-off valve 28 is opened and closed, as well as the duration of each opening and closing, can be preset to keep the first on-off valve 28 intermittently open. Of course, the specific number of times and duration need to be determined through prior testing to ensure that the settings of the number of times and duration can help the compressor 24 start smoothly.

[0050] More preferably, the control method further includes:

[0051] After each closure of the first on / off valve 28, obtain the duration of the closure of the first on / off valve 28 this time;

[0052] Determine if the duration has reached the preset duration;

[0053] If the time reaches the preset time, the current liquid level of the gas-liquid separator 23 is obtained again and it is determined whether the current liquid level has reached the preset liquid level.

[0054] In the preferred embodiment described above, the preset duration can be flexibly set to a specific value by those skilled in the art. If the current liquid level obtained again does not reach the preset liquid level, it indicates that the gas-liquid separator 23 can still be injected with refrigerant. Therefore, the first on-off valve 28 can be reopened at this time to continue injecting refrigerant into the gas-liquid separator 23. If the preset liquid level is reached, it indicates that the gas-liquid separator 23 has contained enough refrigerant. Therefore, the first on-off valve 28 is not opened at this time, but remains closed.

[0055] The current liquid level of the gas-liquid separator 23 is acquired again only after the first on-off valve 28 has been closed for a certain period of time. The system then checks whether the current liquid level has reached the preset level to determine whether the first on-off valve 28 needs to be reopened. Each time the first on-off valve 28 is closed, it takes time for the gas-liquid mixture in the gas-liquid separator 23 to separate into gaseous and liquid refrigerant. In other words, the liquid level may drop after a certain period. Therefore, as long as the preset time is set reasonably, acquiring the current liquid level of the gas-liquid separator 23 only after the first on-off valve 28 has been closed for the preset time will not affect the overall efficiency of refrigerant injection into the gas-liquid separator 23. Furthermore, this setting reduces the number of times the current liquid level of the gas-liquid separator 23 needs to be acquired, thereby reducing the workload of the controller and enabling it to handle more other control operations.

[0056] In some alternative implementations, after each closure of the first on / off valve, the system may receive a user's instruction to the air conditioner requesting the current liquid level of the gas-liquid separator 23 and determining whether it has reached the preset liquid level. If such instruction is received, the system may then obtain the current liquid level of the gas-liquid separator 23 and determine whether it has reached the preset liquid level.

[0057] More preferably, the control method further includes:

[0058] In the step of "obtaining the current liquid level of the gas-liquid separator 23 again and determining whether the current liquid level has reached the preset liquid level", if it is determined that the current liquid level has reached the preset liquid level, the second on-off valve 29 is opened so that the refrigerant in the outdoor heat exchanger 25 flows into the outlet of the compressor 24.

[0059] The second on-off valve 29 is brought to the open state. That is, if the second on-off valve 29 was previously closed, it is opened in this step; if the second on-off valve 29 was already open, it remains open in this step. It should be noted that for other steps of the control method of this invention, if the description "bringing a component to a certain state" is used, the explanation is similar to that of "bringing the second on-off valve 29 to the open state." That is, if the component was previously in a state different from "a certain state," it is switched to that "a certain state" in this step; if the component was already in that "a certain state," it remains in that state in this step. This will not be elaborated further below.

[0060] As mentioned earlier, if the step of "obtaining the current liquid level of the gas-liquid separator 23 again and determining whether the current liquid level has reached the preset liquid level" determines that the current liquid level has reached the preset liquid level, it means that the gas-liquid separator 23 has contained enough refrigerant. Therefore, the second on / off valve 29 can be opened at this time to allow the refrigerant in the outdoor heat exchanger 25 to flow out. Figure 2 In the case of the air conditioner 2 shown, after the second shut-off valve 29 is opened, the refrigerant in the outdoor heat exchanger 25 flows out and passes through the second shut-off valve 29, and then flows sequentially through the indoor expansion valve 21, indoor heat exchanger 22, four-way reversing valve 27, and gas-liquid separator 23, and finally flows into the compressor 24, which further increases the amount of refrigerant in the compressor 24 and further increases the pressure at the outlet of the compressor 24. This helps to raise the outlet pressure of the compressor 24 to the outlet pressure that ensures the normal operation of the compressor 24, and provides a basis for the smooth start-up of the compressor 24 in the future.

[0061] It should be noted that a pipe can also be added to the air conditioner 2, with both ends of the pipe directly connected to the inlet of the second shut-off valve 29 and the compressor 24. In this way, after the second shut-off valve 29 is opened, the refrigerant in the outdoor heat exchanger 25 can also flow into the compressor 24, which helps to increase the outlet pressure of the compressor 24.

[0062] In some alternative implementations, the second shut-off valve 29 may be opened at the same time as the first shut-off valve 28 is opened for the first time. This allows the refrigerant in the outdoor heat exchanger 25 to be discharged more quickly, so that the air conditioner 2 can adjust the air quality for the user as soon as possible.

[0063] More preferably, the control method further includes:

[0064] With the second shut-off valve 29 in the open position, the pressure at the outlet of the compressor 24 is obtained;

[0065] The compressor 24 is selectively activated based on the pressure.

[0066] As previously stated, opening the second on / off valve 29 will increase the pressure at the outlet of the compressor 24. In the preferred embodiment described above, the outlet pressure of the compressor 24 can be monitored when the second on / off valve 29 is open, so that the compressor 24 can be started at an appropriate time.

[0067] In some alternative implementations, the compressor 24 may be turned on after the second on-off valve 29 has been kept open for a set period of time. Of course, the setting of this set period of time should be determined by experiment so that the compressor 24 can start normally after the second on-off valve 29 has been kept open for a set period of time, so that the air conditioner 2 can operate normally.

[0068] More preferably, the step of "selectively starting the compressor 24 according to the pressure" specifically includes:

[0069] Determine if the pressure is within the preset pressure range;

[0070] If the pressure is within the preset pressure range, start compressor 24;

[0071] If the pressure exceeds the preset pressure range, the compressor 24 will remain off.

[0072] The preset pressure range does not exceed the maximum allowable range of the compressor 24 outlet.

[0073] In the preferred embodiment described above, the compressor 24 is started only when the pressure at its outlet is within a preset pressure range; otherwise, it is not started. Furthermore, the preset pressure range does not exceed the maximum allowable pressure range at the compressor 24 outlet. This ensures that the compressor 24 is started only when it is in a normally functioning state, preventing damage to the compressor 24 caused by starting it under unsuitable conditions. The lower limit of the preset pressure range is preferably the minimum allowable pressure at the compressor 24 outlet. This allows the compressor 24 to be turned on as quickly as possible, enabling the air conditioner 2 to adjust the air quality for the user.

[0074] In some alternative implementations, when the second on-off valve is in the open state, the compressor is started when the duration of the second on-off valve's opening reaches a set duration. Of course, the set duration needs to be determined by testing to ensure that the compressor can be started smoothly after the set duration is reached.

[0075] In some alternative implementations, the indoor unit of the air conditioner is equipped with a temperature sensor that can detect the indoor temperature. The step of "selectively starting the compressor based on pressure" may also specifically include: determining whether the pressure is within a preset pressure range; if the pressure is within the preset pressure range, obtaining the indoor temperature; if the indoor temperature is within the preset temperature range (the specific value of the preset temperature range can be set as needed by those skilled in the art, for example, it can be set to a temperature that makes people feel comfortable, such as 23 to 27 degrees Celsius), then not starting the compressor; if the indoor temperature exceeds the preset temperature range, then starting the compressor.

[0076] Preferably, the control method further includes:

[0077] During the operation of compressor 24 to recover refrigerant into outdoor heat exchanger 25, the second on / off valve 29 is closed.

[0078] If refrigerant needs to be recovered into the outdoor heat exchanger 25, the air conditioner 2 needs to be in cooling mode. For the air conditioner 2 in this preferred embodiment, in addition to the compressor 24 needing to be operational, the four-way reversing valve 27 also needs to be in a state that enables the air conditioner to be in cooling mode. When the air conditioner 2 is in cooling mode, the flow direction of the refrigerant in the main refrigerant circulation loop is as follows: Figure 2 As shown, and in Figure 2 The dashed lines inside the four-way reversing valve 27 indicate a closed circuit, and the solid lines indicate a closed circuit. Specifically, the flow direction is as follows: it flows sequentially through the indoor expansion valve 21, indoor heat exchanger 22, four-way reversing valve 27, gas-liquid separator 23, compressor 24, four-way reversing valve 27, outdoor heat exchanger 25, outdoor expansion valve 26, and second shut-off valve 29. After passing through the second shut-off valve 29, the refrigerant flows back to the indoor expansion valve 21. In this preferred embodiment, during the operation of the compressor 24 to recover the refrigerant to the outdoor heat exchanger 25, the second shut-off valve 29 is closed. This prevents the refrigerant from flowing through the second shut-off valve 29 after entering the outdoor heat exchanger 25, thus preventing it from returning to the indoor side of the air conditioner 2. Consequently, the refrigerant is stored in the outdoor heat exchanger 25, achieving refrigerant recovery.

[0079] In some alternative implementations, refrigerant recovery can be achieved without compressor 24. For example, an opening can be provided on the refrigerant pipeline on the outdoor side of air conditioner 2. This opening can be normally sealed with a plug or the like. When refrigerant leakage occurs on the indoor side of air conditioner 2, the plug is removed, and a suction pump is connected to the opening. The refrigerant is then extracted by the suction pump and compressed into liquid and injected into the outdoor heat exchanger 25. Of course, during the refrigerant injection process, the second on / off valve 29 must be in the closed state to prevent the refrigerant from flowing back to the indoor side of air conditioner 2.

[0080] The technical solution of the present invention will now be illustrated with a specific embodiment, still using air conditioner 22. Figure 2 Taking the structure shown as an example, the control method of air conditioner 22 is as follows: Figure 4 As shown, the control method includes:

[0081] S101. In the event of refrigerant leakage on the indoor side of air conditioner 2, the air conditioner 2 shall be put into cooling operation and the second shut-off valve 29 shall be closed.

[0082] S102. After all the refrigerant has entered the outdoor heat exchanger 25, turn off the compressor 24;

[0083] S103, Open the first shut-off valve 28;

[0084] S104. Obtain the current liquid level of the gas-liquid separator 23;

[0085] S105. Determine whether the current liquid level has reached the preset liquid level. If it has, proceed to step S106. If it has not, proceed to step S104.

[0086] S106. Close the first shut-off valve 28;

[0087] S107. Obtain the duration of the closure of the first on / off valve 28 this time;

[0088] S108. Determine whether the time has reached the preset time. If it has, proceed to step S109. If it has not, proceed to step S107.

[0089] S109. Obtain the current liquid level of the gas-liquid separator 23;

[0090] S110. Determine whether the current liquid level has reached the preset liquid level. If it has, proceed to step S111. If it has not, proceed to step S109.

[0091] S111. Continue to keep the first on / off valve 28 closed and open the second on / off valve 29;

[0092] S112, Obtain the pressure at the compressor outlet 24;

[0093] S113. Determine whether the pressure is within the preset pressure range. If yes, proceed to step S114; otherwise, proceed to step S112.

[0094] S114, Start compressor 24.

[0095] Although the above is a combination Figure 2The control method of the present invention is illustrated by the air conditioner 2 shown in the figure. The air conditioner 2 includes a liquid level detection device, a pressure detection device, etc. However, it should be noted that those skilled in the art can select or omit the components in the air conditioner 2 according to the specific circumstances of the steps included in the control method. For example, when the control method of the air conditioner 2 does not involve steps related to the liquid level detection device and the pressure detection device, those skilled in the art can omit these components.

[0096] On the other hand, this application also proposes an air conditioner 2, the controller of which is configured to perform any of the control methods of the air conditioner 2 described above.

[0097] Of course, the alternative implementation methods described above, as well as the alternative implementation methods and preferred implementation methods, can be used in combination to create new implementation methods that are suitable for more specific application scenarios.

[0098] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features but not others included in other embodiments, combinations of features from different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the claims of this invention, any of the claimed embodiments can be used in any combination.

[0099] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A control method for an air conditioner, characterized in that, The air conditioner includes an indoor heat exchanger, a gas-liquid separator, a compressor, and an outdoor heat exchanger, which are connected by pipes to form a refrigerant circulation main loop. The air conditioner also includes a first branch and a first on / off valve disposed on the first branch. The first end of the first branch is connected to the outdoor heat exchanger, and the second end of the first branch is connected to the inlet of the gas-liquid separator. When the first on / off valve is in the open state, the refrigerant in the outdoor heat exchanger can flow into the gas-liquid separator. The control method includes: When the refrigerant has been recovered into the outdoor heat exchanger, the first on / off valve is selectively opened intermittently so that the refrigerant in the outdoor heat exchanger flows into the gas-liquid separator. The step of "selectively keeping the first on / off valve intermittently in the open state" specifically includes: The first on-off valve is intermittently kept in the open state by alternating opening and closing. This step specifically includes: Open the first on / off valve; Obtain the current liquid level of the gas-liquid separator; Determine whether the current liquid level has reached the preset liquid level; The first on / off valve is closed whenever the current liquid level reaches the preset liquid level, and reopened when the current liquid level is lower than the preset liquid level. Wherein, the preset liquid level does not exceed the highest allowable liquid level in the gas-liquid separator; The control method further includes: After each time the first on / off valve is closed, the duration of the closure of the first on / off valve is obtained; Determine whether the duration has reached the preset duration; If the duration reaches the preset duration, the current liquid level of the gas-liquid separator is obtained again and it is determined whether the current liquid level has reached the preset liquid level. The air conditioner also includes a second on / off valve disposed between the outdoor heat exchanger and the indoor heat exchanger. When the second on / off valve is in the open state, the refrigerant in the outdoor heat exchanger can flow into the outlet of the compressor. The control method further includes: In the step of "obtaining the current liquid level of the gas-liquid separator again and determining whether the current liquid level has reached the preset liquid level", if it is determined that the current liquid level has reached the preset liquid level, the second on-off valve is opened so that the refrigerant in the outdoor heat exchanger flows into the outlet of the compressor.

2. The control method for an air conditioner according to claim 1, characterized in that, The control method further includes: When the second on / off valve is in the open state, the pressure at the compressor outlet is obtained; The compressor is selectively activated based on the pressure.

3. The control method for an air conditioner according to claim 2, characterized in that, The step of "selectively starting the compressor according to the pressure" specifically includes: Determine whether the pressure is within a preset pressure range; If the pressure is within the preset pressure range, then the compressor is started; The preset pressure range does not exceed the maximum allowable range of the compressor outlet.

4. The control method for an air conditioner according to claim 3, characterized in that, The step of "selectively starting the compressor according to the pressure" further includes: If the pressure exceeds the preset pressure range, the compressor will remain off.

5. The control method for an air conditioner according to any one of claims 1 to 4, characterized in that, The control method further includes: During the process of the compressor being in operation to recover refrigerant into the outdoor heat exchanger, the second on / off valve is kept closed.

6. An air conditioner, characterized in that, The controller of the air conditioner is configured to perform the control method according to any one of claims 1 to 5.

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