WO2018049722A1

WO2018049722A1 - Multi-split air conditioning system and switching control method for operating mode of indoor units thereof

Info

Publication number: WO2018049722A1
Application number: PCT/CN2016/104675
Authority: WO
Inventors: 周军; 杨时弘; 庄子宝
Original assignee: 广东美的暖通设备有限公司; 美的集团股份有限公司
Priority date: 2016-09-19
Filing date: 2016-11-04
Publication date: 2018-03-22
Also published as: EP3517848B1; US20190212024A1; EP3517848A1; CA3037194A1; CN106440455B; CN106440455A; EP3517848A4

Abstract

A multi-split air conditioning system and a switching control method for an operating mode of indoor units thereof. The method comprises the following steps: when any indoor unit (21, 22, 23, 24) in multiple indoor units (21, 22, 23, 24) receives a mode switching instruction, the indoor unit (21, 22, 23, 24) sends the mode switching instruction to a shunt device (30) (S1); the shunt device (30) performs switching control on a heating control valve or a refrigeration control valve corresponding to the indoor unit (21, 22, 23, 24) according to the received mode switching instruction, releases pressure by controlling a second throttling assembly (34), a first control valve, and a bypass valve in order to reduce a differential pressure across the refrigeration control valve or the heating control valve corresponding to the indoor unit (21, 22, 23, 24), obtains a switching flag bit of a four-way valve, and controls the refrigeration control valve or the heating control valve corresponding to the indoor unit (21, 22, 23, 24) and the four-way valve according to the switching flag bit of the four-way valve (S2).

Description

Multi-line system and switching control method thereof for indoor unit operation mode

Technical field

The invention relates to the technical field of air conditioners, in particular to a switching control method for an indoor unit operating mode in a multi-line system and a multi-line system.

Background technique

The multi-line system is a high-efficiency air-conditioning unit that simultaneously distributes the high-pressure pipe and the low-pressure pipe of the outdoor unit to the corresponding heating indoor unit or the refrigerating indoor unit through a plurality of control valves in the flow dividing device to realize simultaneous heating and cooling. .

In the related art, when the indoor unit performs mode switching and does not involve large mode switching (that is, the four-way valve in the outdoor unit does not need to be switched), the indoor unit receives the heating (cooling) mode to the cooling (heating) mode. When the switching command is made, the heating control valve (refrigeration control valve) corresponding to the indoor unit in the flow dividing device is turned off after a delay of t1 time, and the refrigeration control valve (heating control valve) is turned on after a delay of t1 + t2, thereby completing the Mode switching of the indoor unit. However, during the switching process, when the refrigeration control valve (heating control valve) is opened, the pressure difference between the two sides of the refrigeration control valve (heating control valve) is large, and the refrigerant impact causes a large pipe vibration, and the corresponding pipe There is a hidden danger of impact cracking in the road system. At the same time, a large refrigerant impact will produce impact noise and affect the noise quality of the product.

When the indoor unit performs mode switching and involves large mode switching (ie, the four-way valve in the outdoor unit needs to be switched), the four-way valve in the outdoor unit and the refrigeration control valve (heating control valve) in the flow dividing device are independently performed. Switching, that is, switching twice, will cause two large impacts on the corresponding piping system and generate two refrigerant impact noises, which seriously affect the reliability of the piping system and product noise quality.

Summary of the invention

The present invention aims to solve at least one of the technical problems in the related art to some extent.

Therefore, an object of the present invention is to provide a switching control method for an indoor unit operating mode in a multi-line system, which is configured to reduce pressure by controlling a second throttling assembly, a first control valve, and a bypass valve to reduce mode switching. The differential pressure between the front and rear of the cooling and heating control valve, and the control of the cooling and heating control valve and the four-way valve according to the switching position of the four-way valve, thereby better improving the hidden trouble of the pipeline caused by the refrigerant impact, Reduce the corresponding refrigerant impact noise, effectively improve the system reliability and noise quality.

Another object of the present invention is to propose a multi-line system.

In order to achieve the above object, an embodiment of the present invention provides a handover control method for an indoor unit operation mode in a multi-line system, where the multi-line system includes an outdoor unit, a flow dividing device, and a plurality of indoor units, wherein the outdoor unit The machine includes a compressor and a four-way valve, the flow dividing device including a first heat exchange component, a second heat exchange component, and the first change a first throttle assembly between an outlet of the first heat exchange passage of the heat assembly and an inlet of the first heat exchange passage of the second heat exchange assembly, and a first exchange disposed at the second heat exchange assembly a second throttle assembly between an outlet of the heat flow path and an inlet of the second heat exchange passage of the second heat exchange component, and an outlet of the first heat exchange flow path disposed in the second heat exchange component a bypass valve between the low pressure lines of the flow dividing device, a heating control valve and a refrigeration control valve corresponding to each of the plurality of indoor units, the first throttle assembly including the first control a valve, the method comprising the steps of: when any one of the plurality of indoor units receives a mode switching instruction, the indoor unit transmits a mode switching instruction to the flow dividing device; and the flow dividing device receives the The obtained mode switching instruction performs switching control of the heating control valve or the cooling control valve corresponding to the indoor unit, and performs pressure relief by controlling the second throttle assembly, the first control valve, and the bypass valve Lower the refrigeration control valve corresponding to the indoor unit or a differential pressure of the front and rear of the thermal control valve, and a switching flag of the four-way valve, and a cooling control valve or a heating control valve corresponding to the indoor unit according to the switching flag of the four-way valve and the four-way The valve is controlled.

According to the switching control method of the indoor unit operating mode in the multi-line system according to the embodiment of the present invention, when any one of the plurality of indoor units receives the mode switching instruction, the indoor unit transmits the mode switching instruction to the shunt device, and the shunting The device performs switching control of the heating control valve or the cooling control valve corresponding to the indoor unit according to the received mode switching instruction, and depressurizes by controlling the second throttle assembly, the first control valve and the bypass valve to reduce the The differential pressure between the front and rear of the refrigeration control valve or the heating control valve corresponding to the indoor unit, and the switching flag of the four-way valve, and the refrigeration control valve or the heating control valve corresponding to the indoor unit according to the switching flag of the four-way valve And the four-way valve is controlled, thereby better improving the hidden trouble of the pipeline caused by the refrigerant impact, reducing the corresponding refrigerant impact noise, and effectively improving the reliability and noise quality of the system.

According to an embodiment of the present invention, the switching flag of the four-way valve includes 0 and 1, wherein when the switching flag of the four-way valve is equal to 0, the operating mode of the multi-line system is from the main cooling mode Switch to the pure cooling mode, or switch from the main cooling mode to the main cooling mode, or switch from the main heating mode to the pure heating mode, or switch from the main heating mode to the main heating mode; when the four-way valve When the switching flag is equal to 1, the operation mode of the multi-line system is switched from the main heating mode to the main cooling mode, or the main cooling mode is switched to the main heating mode, or the main cooling mode is switched to the pure heating mode. Or switch from the main heating mode to the pure cooling mode.

According to an embodiment of the present invention, when the shunting device determines that the indoor unit is switched from the heating mode to the cooling mode according to the received mode switching instruction, and the switching flag of the four-way valve is equal to 0, After the delay time is delayed for a first predetermined time, the shunting device controls the heating control valve corresponding to the indoor unit to be closed, and controls the second throttle assembly and the first control valve to be in an open state, and the second delay After the preset time, the second throttle assembly and the first control valve are both controlled to be in a closed state, and the corresponding refrigeration control valve of the indoor unit is controlled to be in an open state; or, the flow dividing device is delayed. After the first preset time, controlling the heating control valve corresponding to the indoor unit to be closed, and controlling the second throttle assembly and the bypass valve to be in an open state, after delaying the second preset time, Controlling the second The throttle assembly and the bypass valve are both in a closed state, and the corresponding refrigeration control valve of the indoor unit is controlled to be in an open state.

According to an embodiment of the present invention, when the shunting device determines that the indoor unit is switched from the heating mode to the cooling mode according to the received mode switching instruction, and the switching flag of the four-way valve is equal to 1, After the delay time is delayed for a first predetermined time, the shunting device controls the heating control valve corresponding to the indoor unit to be closed, and controls the second throttle assembly and the first control valve to be in an open state, and the second delay After the preset time, controlling the second throttle assembly and the first control valve to be in a closed state, and controlling the corresponding refrigeration control valve of the indoor unit to be in an open state, and controlling the four-way valve to switch; or After the first preset time is delayed, the shunting device controls the heating control valve corresponding to the indoor unit to be closed, and controls the second throttling assembly and the bypass valve to be in an open state. After the second preset time, controlling the second throttle assembly and the bypass valve to be in a closed state, and controlling the corresponding refrigeration control valve of the indoor unit to be in an open state, and controlling the four-way valve Switch.

According to an embodiment of the present invention, when the shunting device determines that the indoor unit is switched from the cooling mode to the heating mode according to the received mode switching instruction, and the switching flag of the four-way valve is equal to 0, After the first preset time is delayed, the shunting device controls the corresponding refrigeration control valve of the indoor unit to be closed, and controls the second throttle assembly and the first control valve to be in an open state, and delays the second pre- After the time is set, the second throttle assembly and the first control valve are both controlled to be in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be in an open state; or, the flow dividing device is delayed in the After the first preset time, the refrigeration control valve corresponding to the indoor unit is controlled to be closed, and the second throttle assembly and the bypass valve are both controlled to be in an open state, and after the second preset time is delayed, the control is performed. The second throttle assembly and the bypass valve are both in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be in an open state.

According to an embodiment of the present invention, when the shunting device determines that the indoor unit is switched from the cooling mode to the heating mode according to the received mode switching instruction, and the switching flag of the four-way valve is equal to 1, After the first preset time is delayed, the shunting device controls the corresponding refrigeration control valve of the indoor unit to be closed, and controls the second throttle assembly and the first control valve to be in an open state, and delays the second pre- After the time is set, the second throttle assembly and the first control valve are both controlled to be in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be in an open state, and the four-way valve is controlled to be switched; or After the first preset time is delayed, the shunting device controls the corresponding refrigeration control valve of the indoor unit to be closed, and controls the second throttling component and the bypass valve to be in an open state, delaying After the second preset time, controlling the second throttle assembly and the bypass valve to be in a closed state, and controlling the heating control valve corresponding to the indoor unit to be in an open state, and controlling the four-way valve Switch.

To achieve the above object, a multi-line system according to another embodiment of the present invention includes: an outdoor unit including a compressor and a four-way valve; a plurality of indoor units; a flow dividing device, the flow dividing device including a first heat exchange component, a second heat exchange component, disposed between an outlet of the first heat exchange flow path of the first heat exchange component and an inlet of the first heat exchange flow path of the second heat exchange component a first throttle assembly, a second throttle assembly disposed between an outlet of the first heat exchange passage of the second heat exchange assembly and an inlet of the second heat exchange passage of the second heat exchange assembly, Provided in the second heat exchange group a bypass valve between an outlet of the first heat exchange passage and a low pressure line of the flow dividing device, a heating control valve and a refrigeration control valve corresponding to each of the plurality of indoor units, The first throttle assembly includes a first control valve, wherein when any one of the plurality of indoor units receives a mode switching instruction, the indoor unit transmits a mode switching instruction to the flow dividing device; The flow dividing device further includes: a control module, configured to perform switching control of the heating control valve or the cooling control valve corresponding to the indoor unit according to the received mode switching instruction, and control the second throttle component The first control valve and the bypass valve perform pressure relief to reduce a differential pressure between the front and rear of the refrigeration control valve or the heating control valve corresponding to the indoor unit, and obtain a switching flag of the four-way valve, and according to The switching flag of the four-way valve controls the refrigeration control valve or the heating control valve and the four-way valve corresponding to the indoor unit.

According to the multi-line system of the embodiment of the present invention, when any one of the plurality of indoor units receives the mode switching instruction, the indoor unit transmits the mode switching instruction to the branching device, and the control module in the branching device receives the The mode switching instruction performs switching control of the heating control valve or the cooling control valve corresponding to the indoor unit, and depressurizes by controlling the second throttle unit, the first control valve and the bypass valve to reduce the corresponding cooling of the indoor unit The front and rear pressure difference of the control valve or the heating control valve, and the switching flag of the four-way valve are obtained, and the refrigeration control valve or the heating control valve and the four-way valve corresponding to the indoor unit are performed according to the switching flag of the four-way valve. Control, so as to better improve the pipeline cracking caused by refrigerant impact, reduce the corresponding refrigerant impact noise, and effectively improve the system reliability and noise quality.

According to an embodiment of the present invention, when the control module determines that the indoor unit is switched from the heating mode to the cooling mode according to the received mode switching instruction, and the switching flag of the four-way valve is equal to 0, After the delay of the first preset time, the control module controls the heating control valve corresponding to the indoor unit to be closed, and controls the second throttle assembly and the first control valve to be in an open state, and the second delay After the preset time, the second throttle assembly and the first control valve are both in a closed state, and the corresponding refrigeration control valve of the indoor unit is controlled to be in an open state; or, the control module delays the After the first preset time, controlling the heating control valve corresponding to the indoor unit to be closed, and controlling the second throttle assembly and the bypass valve to be in an open state, after delaying the second preset time, The second throttle assembly and the bypass valve are both controlled to be in a closed state, and the corresponding refrigeration control valve of the indoor unit is controlled to be in an open state.

According to an embodiment of the present invention, when the control module determines that the indoor unit is switched from the heating mode to the cooling mode according to the received mode switching instruction, and the switching flag of the four-way valve is equal to 1, The control module controls the heating control valve corresponding to the indoor unit to be closed after delaying the first preset time, and controls the second throttle component And the first control valve is in an open state, after the second preset time delay, controlling the second throttle assembly and the first control valve to be in a closed state, and controlling the refrigeration control corresponding to the indoor unit The valve is in an open state, and the four-way valve is controlled to be switched; or the control module controls the heating control valve corresponding to the indoor unit to be closed after delaying the first predetermined time, and controls the first The two throttle assembly and the bypass valve are both in an open state, and after the second preset time is delayed, controlling the second throttle assembly and the bypass valve to be in a closed state, and controlling the indoor unit The corresponding refrigeration control valve is in an open state and the four-way valve is controlled to switch.

According to an embodiment of the present invention, when the control module determines that the indoor unit is switched from the cooling mode to the heating mode according to the received mode switching instruction, and the switching flag of the four-way valve is equal to 0, where After the delay of the first preset time, the control module controls the corresponding refrigeration control valve of the indoor unit to be closed, and controls the second throttle assembly and the first control valve to be in an open state, and delays the second pre- After the time is set, the second throttle assembly and the first control valve are both controlled to be in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be in an open state; or, the control module delays the After the first preset time, the refrigeration control valve corresponding to the indoor unit is controlled to be closed, and the second throttle assembly and the bypass valve are both controlled to be in an open state, and after the second preset time is delayed, the control is performed. The second throttle assembly and the bypass valve are both in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be in an open state.

According to an embodiment of the present invention, when the control module determines that the indoor unit is switched from the cooling mode to the heating mode according to the received mode switching instruction, and the switching flag of the four-way valve is equal to 1, After the delay of the first preset time, the control module controls the corresponding refrigeration control valve of the indoor unit to be closed, and controls the second throttle assembly and the first control valve to be in an open state, and delays the second pre- After the time is set, the second throttle assembly and the first control valve are both controlled to be in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be in an open state, and the four-way valve is controlled to be switched; or After the first preset time is delayed, the control module controls the corresponding refrigeration control valve of the indoor unit to be closed, and controls the second throttle assembly and the bypass valve to be in an open state, and the delay After the second preset time, controlling the second throttle assembly and the bypass valve to be in a closed state, and controlling the heating control valve corresponding to the indoor unit to be in an open state, and controlling the four-way valve Switch.

DRAWINGS

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from

1 is a schematic structural diagram of a multi-line system according to an embodiment of the present invention;

2 is a flowchart of a method for switching control of an indoor unit operation mode in a multi-line system according to an embodiment of the present invention;

3 is a flow chart of a method for switching control of an indoor unit operating mode in a multi-line system according to an embodiment of the present invention.

Reference numerals: outdoor unit 10, first indoor unit 21, second indoor unit 22, third indoor unit 23, fourth indoor unit 24, heating control valves SV1B, SV2B, SV3B and SV4B, refrigeration control valves SV1, SV2 , SV3 and SV4, flow dividing device 30, first heat exchange component 31, second heat exchange component 32, first throttle component 33, second throttle component 34, bypass valve SVME, first control valve SVMC, first The throttle element EXV2 and the second control valve SVP.

detailed description

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals are used to refer to the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are intended to be illustrative of the invention and are not to be construed as limiting.

A switching control method for an indoor unit operating mode and a multi-line system in a multi-line system according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

1 is a block diagram showing the structure of a multi-line system according to an embodiment of the present invention.

As shown in FIG. 1, the multi-line system may include an outdoor unit, a flow dividing device, and a plurality of indoor units. Among them, the outdoor unit includes a compressor and a four-way valve. The flow dividing device includes a first heat exchange component, a second heat exchange component, a first portion disposed between an outlet of the first heat exchange passage of the first heat exchange component and an inlet of the first heat exchange flow path of the second heat exchange component a throttle assembly, a second throttle assembly disposed between the outlet of the first heat exchange passage of the second heat exchange assembly and the inlet of the second heat exchange passage of the second heat exchange assembly, disposed in the second exchange a bypass valve between the outlet of the first heat exchange passage of the heat assembly and the low pressure line of the flow dividing device, a heating control valve and a refrigeration control valve corresponding to each of the plurality of indoor units, the first section The flow assembly includes a first control valve.

2 is a flow chart of a method for switching control of an indoor unit operating mode in a multi-line system according to an embodiment of the present invention. As shown in FIG. 2, the switching control method of the indoor unit operating mode in the multi-line system may include the following steps:

S1. When any one of the plurality of indoor units receives the mode switching instruction, the indoor unit transmits the mode switching command to the flow dividing device.

S2. The flow dividing device performs switching control on the heating control valve or the cooling control valve corresponding to the indoor unit according to the received mode switching instruction, and performs pressure relief by controlling the second throttle assembly, the first control valve and the bypass valve. Decrease the differential pressure between the front and rear of the refrigeration control valve or the heating control valve corresponding to the indoor unit, and obtain the switching flag of the four-way valve, and according to the switching flag of the four-way valve, the refrigeration control valve or the heating corresponding to the indoor unit The control valve and the four-way valve are controlled.

According to an embodiment of the present invention, the switching flag of the four-way valve includes 0 and 1, wherein when the switching flag of the four-way valve is equal to 0, the operating mode of the multi-line system is switched from the main cooling mode to the pure cooling mode. Or switch from the main cooling mode to the main cooling mode, or switch from the main heating mode to the pure heating mode, or switch from the main heating mode to the main heating mode; when the switching flag of the four-way valve is equal to 1, more The operating mode of the online system is switched from the main heating mode to the main cooling mode, or the main cooling mode is switched to the main heating mode, or the main cooling mode is switched to the pure heating mode. Or switch from the main heating mode to the pure cooling mode.

Specifically, the multi-line system may include a main cooling mode, a main heating mode, a pure cooling mode, and a pure heating mode. When the indoor unit in the multi-line system performs mode switching, the operating mode of the entire system is sometimes changed (ie, The working mode of the outdoor unit). For example, suppose that there are two indoor units in a multi-line system, in which a large-cooling indoor unit operates in a heating mode, a small-cooling indoor unit operates in a cooling mode, and a multi-line system is in a main heating mode. When the user switches the operation mode of the large-cooling indoor unit to the cooling mode, the multi-line system will switch from the main heating mode to the pure cooling mode. At this time, the large mode switching is involved, that is, the four-way valve in the outdoor unit needs to be switched. The switching flag of the four-way valve is equal to 1; when the user switches the operation mode of the small-cooling indoor unit to the heating mode, the multi-line system will switch from the main heating mode to the pure heating mode, and no large mode switching is involved at this time. That is, the four-way valve of the outdoor unit does not need to be switched, and the switching flag of the four-way valve is equal to zero. That is to say, when the indoor unit performs mode switching, it is also judged whether the system needs to perform mode switching. If necessary, the switching flag of the four-way valve is equal to 1; if not, the switching flag of the four-way valve is equal to 0. Then, the refrigeration control valve or the heating control valve and the four-way valve corresponding to the indoor unit are controlled according to the mode switching command and the switching flag of the four-way valve.

According to an embodiment of the present invention, when the shunting device determines, according to the received mode switching instruction, that the indoor unit is switched from the heating mode to the cooling mode, and the switching flag of the four-way valve is equal to 0, wherein the shunting device is delayed After the first preset time, the heating control valve corresponding to the indoor unit is controlled to be closed, and the second throttle unit and the first control valve are both controlled to be in an open state, and after the second preset time is delayed, the second throttle is controlled. The component and the first control valve are both in a closed state, and the corresponding refrigeration control valve of the indoor unit is controlled to be in an open state; or, the flow dividing device controls the corresponding heating control valve of the indoor unit to be closed after a delay of the first preset time And controlling the second throttle component and the bypass valve to be in an open state, after delaying the second preset time, controlling the second throttle component and the bypass valve to be in a closed state, and controlling the refrigeration control corresponding to the indoor unit The valve is open. The first preset time and the second preset time may be calibrated according to actual conditions.

Specifically, as shown in FIG. 1, it is assumed that the first to third indoor units operate in the heating mode (the refrigerant performs the heating cycle along the solid line), and the fourth indoor unit operates in the cooling mode (the refrigerant performs the refrigeration cycle along the dotted line). ), and the multi-line system is in the main heating mode. When the first indoor unit (small-cooling indoor unit) receives the mode switching instruction for switching from the heating mode to the cooling mode, the indoor unit transmits the mode switching command to the flow dividing device, and determines that the multi-line system is heated by the main The mode is switched to the main heating mode, that is, the system working mode remains unchanged, and the switching flag of the four-way valve is equal to zero.

The flow dividing device controls the heating control valve corresponding to the first indoor unit to be closed after delaying the first preset time, and controls the second throttle assembly and the first control valve to be in an open state (or control the second throttle assembly) And the bypass valve are both in the open state), the refrigerant passes through the first control valve and the heating indoor unit, passes through the second throttle assembly, enters the low pressure pipe of the flow dividing device, and shortly increases the pressure at the low pressure pipe, thereby reducing the first The differential pressure between the front and rear of the refrigeration control valve corresponding to the indoor unit. Then, after the second preset time is delayed, the second throttle component and the first control valve are both controlled to be in a closed state (or, the second section is controlled) Both the flow component and the bypass valve are in a closed state, and at the same time, the corresponding refrigeration control valve of the indoor unit is controlled to be in an open state, and the four-way valve maintains the current state. Thereby, the second throttle assembly, the first control valve and the bypass valve are controlled to effectively reduce the differential pressure before and after the refrigeration control valve, thereby effectively reducing the instantaneous impact of the refrigerant on the corresponding pipeline system and reducing the impact noise generated by the refrigerant impact. Effectively improve system reliability and noise quality.

According to another embodiment of the present invention, when the shunting device determines, according to the received mode switching instruction, that the indoor unit is switched from the cooling mode to the heating mode, and the switching flag of the four-way valve is equal to 0, wherein the shunt device is extended After the first preset time, the refrigeration control valve corresponding to the indoor unit is controlled to be closed, and the second throttle component and the first control valve are both turned on, and after the second preset time is delayed, the second throttle is controlled. The component and the first control valve are both in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be in an open state; or, the flow dividing device controls the corresponding refrigeration control valve of the indoor unit to be closed after a delay of the first preset time And controlling the second throttle component and the bypass valve to be in an open state, after the second preset time delay, controlling the second throttle component and the bypass valve to be in a closed state, and controlling the corresponding heating of the indoor unit The control valve is open.

Specifically, as shown in FIG. 1, it is assumed that the fourth indoor unit receives the mode switching command for switching from the cooling mode to the heating mode, and the indoor unit transmits the mode switching command to the flow dividing device, and determines that the multi-connection system is determined by the main The heating mode is switched to the pure heating mode, and the switching flag of the four-way valve is equal to zero.

The flow dividing device controls the cooling control valve corresponding to the fourth indoor unit to be closed after delaying the first preset time, and simultaneously controls the second throttle unit and the first control valve to be in an open state (or control the second throttle component and The bypass valve is in an open state to perform pressure relief, reducing a differential pressure between the front and rear of the heating control valve corresponding to the fourth indoor unit, and then, after a second preset time delay, controlling the second throttle component and the first The control valves are all in a closed state (or both the second throttle assembly and the bypass valve are in a closed state), and the heating control valve corresponding to the indoor unit is controlled to be in an open state, and the four-way valve maintains the current state. Thereby, the front throttle pressure difference of the heating control valve is effectively reduced by controlling the second throttle assembly, the first control valve and the bypass valve, thereby effectively reducing the instantaneous impact of the refrigerant on the corresponding pipeline system and reducing the impact of the refrigerant shock. Noise, effectively improving system reliability and noise quality.

According to an embodiment of the present invention, when the shunting device determines, according to the received mode switching instruction, that the indoor unit is switched from the heating mode to the cooling mode, and the switching flag of the four-way valve is equal to 1, wherein the shunt device is delayed. After the first preset time, the heating control valve corresponding to the indoor unit is controlled to be closed, and the second throttle unit and the first control valve are both controlled to be in an open state, and after the second preset time is delayed, the second throttle is controlled. The component and the first control valve are both in a closed state, and the corresponding refrigeration control valve of the indoor unit is controlled to be in an open state, and the four-way valve is controlled to be switched; or the flow dividing device controls the indoor after a first preset time delay The heating control valve corresponding to the machine is closed, and the second throttle component and the bypass valve are controlled to be in an open state, and after the second preset time is delayed, the second throttle component and the bypass valve are controlled to be in a closed state, and The refrigeration control valve corresponding to the indoor unit is controlled to be in an open state, and the four-way valve is controlled to be switched.

Specifically, after a large number of tests and verifications, it was found that the indoor unit pair in the shunt device when performing large mode switching The minimum pressure difference between the front and rear of the refrigeration control valve (heating control valve) is the best time for switching the refrigeration control valve (heating control valve). Therefore, when the large mode is switched, the four-way valve and the cooling control are controlled. The valve (heating control valve) operates at the same time, which can effectively reduce the instantaneous impact of the refrigerant on the corresponding pipeline system and reduce the impact noise generated by the refrigerant impact.

Specifically, as shown in FIG. 1 , it is assumed that the second indoor unit (large cooling capacity indoor unit) receives a mode switching command for switching from the heating mode to the cooling mode, and the indoor unit transmits the mode switching command to the flow dividing device and simultaneously determines The multi-line system is switched from the main heating mode to the main cooling mode, and the switching flag of the four-way valve is equal to 1.

The flow dividing device controls the heating control valve corresponding to the second indoor unit to be closed after delaying the first preset time, and controls the second throttle unit and the first control valve to be in an open state (or control the second throttle assembly) And the bypass valve are both in an open state) to perform pressure relief, reducing a differential pressure between the front and rear of the refrigeration control valve corresponding to the second indoor unit, and then, after a second preset time delay, controlling the second throttle component and the first The control valves are all in a closed state (or, the second throttle assembly and the bypass valve are both in a closed state), and the corresponding refrigeration control valve of the indoor unit is controlled to be in an open state, and the four-way valve is controlled to be switched, thereby effectively reducing The number of times the refrigerant hits the pipeline. Moreover, when the large mode switching is performed, the front and rear pressure difference of the refrigeration control valve is the smallest, the impact at the time of switching is minimum, and the front and rear pressures of the refrigeration control valve can be further reduced by controlling the second throttle assembly, the first control valve and the bypass valve. The difference is that the differential pressure difference between the front and rear of the refrigeration control valve is smaller, thereby significantly improving the refrigerant impact caused by the mode switching of the indoor unit and reducing the impact noise generated by the refrigerant impact, thereby effectively improving the reliability and noise quality of the system.

According to another embodiment of the present invention, when the shunting device determines, according to the received mode switching instruction, that the indoor unit is switched from the cooling mode to the heating mode, and the switching flag of the four-way valve is equal to 1, wherein the shunt device is extended After the first preset time, the refrigeration control valve corresponding to the indoor unit is controlled to be closed, and the second throttle component and the first control valve are both turned on, and after the second preset time is delayed, the second throttle is controlled. The component and the first control valve are both in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be in an open state, and the four-way valve is controlled to be switched; or the flow dividing device controls the first preset time after the delay The refrigeration control valve corresponding to the indoor unit is closed, and the second throttle component and the bypass valve are both controlled to be in an open state, and after the second preset time is delayed, the second throttle component and the bypass valve are controlled to be in a closed state, and The heating control valve corresponding to the indoor unit is controlled to be in an open state, and the four-way valve is controlled to be switched.

Specifically, as shown in FIG. 1, it is assumed that the first to third indoor units operate in the cooling mode, the fourth indoor unit operates in the heating mode, and the multi-line system is in the main cooling mode. When the second indoor unit (large cooling capacity indoor unit) receives the mode switching instruction for switching from the cooling mode to the heating mode, the indoor unit transmits the mode switching command to the flow dividing device, and simultaneously determines that the multi-line system is in the main cooling mode. Switch to the main heating mode, at which point the switching flag of the four-way valve is equal to 1.

The flow dividing device controls the cooling control valve corresponding to the second indoor unit to be closed after delaying the first preset time, and simultaneously controls the second throttle unit and the first control valve to be in an open state (or control the second throttle component and The bypass valve is in an open state to perform pressure relief, reducing a differential pressure between the front and rear of the heating control valve corresponding to the second indoor unit, and then, after a second preset time delay, controlling the second throttle component and the first The control valves are all closed (or, control the second throttle assembly and The bypass valve is in the closed state), and the heating control valve corresponding to the indoor unit is controlled to be in an open state, and the four-way valve is controlled to switch, thereby effectively reducing the number of times the refrigerant is impacted on the pipeline. Moreover, when the large mode switching is performed, the front and rear pressure difference of the heating control valve is the smallest, the impact at the time of switching is minimum, and the heating control valve can be further reduced by controlling the second throttle assembly, the first control valve, and the bypass valve. The pressure difference between the front and the rear makes the front and rear pressure difference of the heating control valve smaller, thereby significantly improving the refrigerant impact caused by the mode switching of the indoor unit and reducing the impact noise generated by the refrigerant impact, thereby effectively improving the reliability and noise quality of the system.

In order to make the present invention more clearly understood by those skilled in the art, FIG. 3 is a flowchart of a method for switching control of an indoor unit operation mode in a multi-line system according to a specific example of the present invention.

As shown in FIG. 3, the switching control method of the indoor unit operating mode in the multi-line system may include the following steps:

S101, the indoor unit is in a heating (cold) mode.

S102. The indoor unit receives a mode switching instruction that is switched from the heating (cold) mode to the cooling (heat) mode.

S103, the corresponding heating (cold) control valve is delayed by the T1 time.

S104, depressurizing by controlling the second throttle assembly, the first control valve and the bypass valve, and closing for a time delay of T2.

S105. Determine whether the switching flag of the four-way valve is 1. If yes, go to step S107; if no, go to step S106.

S106, controlling the corresponding cooling (heat) control valve to open.

S107, while controlling the switching of the four-way valve, controlling the corresponding cooling (heat) control valve to open.

S108, complete mode switching.

In the above, according to the switching control method of the indoor unit operation mode in the multi-line system according to the embodiment of the present invention, when any one of the plurality of indoor units receives the mode switching instruction, the indoor unit transmits the mode switching instruction Providing a flow dividing device, the flow dividing device switching control of the heating control valve or the cooling control valve corresponding to the indoor unit according to the received mode switching instruction, and discharging by controlling the second throttle component, the first control valve and the bypass valve Pressing to reduce the differential pressure between the front and rear of the refrigeration control valve or the heating control valve corresponding to the indoor unit, and to obtain the switching flag of the four-way valve, and according to the switching flag of the four-way valve, the refrigeration control valve corresponding to the indoor unit Or the heating control valve and the four-way valve are controlled, thereby better improving the hidden trouble of the pipeline caused by the refrigerant impact, reducing the corresponding refrigerant impact noise, and effectively improving the reliability and noise quality of the system.

The multi-line system of the embodiment of the present invention will be described in detail below.

As shown in FIG. 1, the multi-line system may include an outdoor unit 10, a plurality of indoor units, and a flow dividing device 30.

Among them, the outdoor unit 10 includes a compressor and a four-way valve (both not specifically shown in the drawings). The flow dividing device 30 includes a first heat exchange component 31, a second heat exchange component 32, an outlet of the first heat exchange flow path disposed at the first heat exchange component 31, and a first heat exchange flow path of the second heat exchange component 32. a first throttle assembly 33 between the inlets, a second section disposed between the outlet of the first heat exchange passage of the second heat exchange assembly 32 and the inlet of the second heat exchange passage of the second heat exchange assembly 32 Stream component 34, disposed in a bypass valve SVME between the outlet of the first heat exchange passage of the second heat exchange unit 32 and the low pressure line of the flow dividing device 30, a heating control valve corresponding to each of the plurality of indoor units, and refrigeration Control valve and control module (not specifically shown in the figure). The first throttle assembly 33 includes a first control valve SVMC and the second throttle assembly 35 includes a first throttle element EXV2 and a second control valve SVP.

The plurality of indoor units may be the first indoor unit 21, the second indoor unit 22, the third indoor unit 23, and the fourth indoor unit 24, and the first indoor unit 21 corresponds to the heating control valve SV1B and the cooling control valve SV1, and the second indoor The machine 22 corresponds to the heating control valve SV2B and the cooling control valve SV2, the third indoor unit 23 corresponds to the heating control valve SV3B and the cooling control valve SV3, and the fourth indoor unit 24 corresponds to the heating control valve SV4B and the cooling control valve SV4.

When any one of the plurality of indoor units receives the mode switching instruction, the indoor unit transmits a mode switching instruction to the flow dividing device 30, and the control module in the flow dividing device 30 corresponds to the indoor unit according to the received mode switching instruction. The heating control valve or the refrigeration control valve performs switching control, and depressurizes by controlling the second throttle assembly 34, the first control valve SVMC and the bypass valve SVME to reduce the refrigeration control valve or the heating control corresponding to the indoor unit The front and rear pressure difference of the valve, and the switching flag of the four-way valve are obtained, and the refrigeration control valve or the heating control valve and the four-way valve corresponding to the indoor unit are controlled according to the switching flag of the four-way valve.

According to an embodiment of the present invention, the switching flag of the four-way valve includes 0 and 1, wherein when the switching flag of the four-way valve is equal to 0, the operating mode of the multi-line system is switched from the main cooling mode to the pure cooling mode. Or switch from the main cooling mode to the main cooling mode, or switch from the main heating mode to the pure heating mode, or switch from the main heating mode to the main heating mode; when the switching flag of the four-way valve is equal to 1, more The operating mode of the online system is switched from the main heating mode to the main cooling mode, or the main cooling mode is switched to the main heating mode, or the main cooling mode is switched to the pure heating mode, or the main heating mode is switched to the pure cooling mode. mode.

According to an embodiment of the present invention, when the control module determines, according to the received mode switching instruction, that the indoor unit is switched from the heating mode to the cooling mode, and the switching flag of the four-way valve is equal to 0, wherein the control module is delayed. After the first preset time, the heating control valve corresponding to the indoor unit is controlled to be closed, and the second throttle unit 34 and the first control valve SVMC are both controlled to be in an open state, and after a second preset time delay, the second control is performed. The throttle assembly 34 and the first control valve SVMC are both in a closed state, and control the corresponding refrigeration control valve of the indoor unit to be in an open state; or, the control module controls the corresponding system of the indoor unit after delaying the first preset time The thermal control valve is closed, and the second throttle assembly 34 and the bypass valve SVME are both controlled to be in an open state, and after the second predetermined time delay, the second throttle assembly 34 and the bypass valve SVME are controlled to be in a closed state, and The refrigeration control valve corresponding to the indoor unit is controlled to be in an open state.

According to another embodiment of the present invention, when the control module determines that the indoor unit is switched from the cooling mode to the heating mode according to the received mode switching instruction, and the switching flag of the four-way valve is equal to 0, wherein the control module is extended After the first preset time, the refrigeration control valve corresponding to the indoor unit is controlled to be closed, and the second throttle assembly 34 and the first control valve SVMC are both controlled to be in an open state, and after a second preset time delay, the second control is performed. The throttle assembly 34 and the first control valve SVMC are both Is in a closed state, and controls the heating control valve corresponding to the indoor unit to be in an open state; or, after delaying the first preset time, the control module controls the corresponding refrigeration control valve of the indoor unit to be closed, and controls the second throttle The component 34 and the bypass valve SVME are both in an open state, and after the second predetermined time delay, the second throttle assembly 34 and the bypass valve SVME are controlled to be in a closed state, and the corresponding heating control valve of the indoor unit is controlled to be Open state.

According to an embodiment of the present invention, when the control module determines, according to the received mode switching instruction, that the indoor unit is switched from the heating mode to the cooling mode, and the switching flag of the four-way valve is equal to 1, wherein the control module is delayed. After the first preset time, the heating control valve corresponding to the indoor unit is controlled to be closed, and the second throttle unit 34 and the first control valve SVMC are both controlled to be in an open state, and after a second preset time delay, the second control is performed. The throttle assembly 34 and the first control valve SVMC are both in a closed state, and control the corresponding refrigeration control valve of the indoor unit to be in an open state, and control the four-way valve to switch; or, the control module is delayed after the first preset time Controlling the heating control valve corresponding to the indoor unit to be closed, and controlling the second throttle assembly 34 and the bypass valve SVME to be in an open state, and after delaying the second preset time, controlling the second throttle assembly 34 and bypassing The valve SVME is in a closed state, and controls the corresponding refrigeration control valve of the indoor unit to be in an open state, and controls the four-way valve to switch.

According to another embodiment of the present invention, when the control module determines, according to the received mode switching instruction, that the indoor unit is switched from the cooling mode to the heating mode, and the switching flag of the four-way valve is equal to 1, wherein the control module is extended After the first preset time, the refrigeration control valve corresponding to the indoor unit is controlled to be closed, and the second throttle assembly 34 and the first control valve SVMC are both controlled to be in an open state, and after a second preset time delay, the second control is performed. The throttle assembly 34 and the first control valve SVMC are both in a closed state, and control the heating control valve corresponding to the indoor unit to be in an open state, and control the four-way valve to switch; or, the control module is delayed for a first preset time After that, the refrigeration control valve corresponding to the indoor unit is controlled to be closed, and the second throttle assembly 34 and the bypass valve SVME are controlled to be in an open state, and after the second preset time is delayed, the second throttle assembly 34 and the bypass are controlled. The valve SVME is in a closed state, and controls the heating control valve corresponding to the indoor unit to be in an open state, and controls the four-way valve to switch.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " After, "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inside", "Outside", "Clockwise", "Counterclockwise", "Axial", The orientation or positional relationship of the "radial", "circumferential", etc. is based on The orientation or positional relationship shown in the drawings is merely for the convenience of the description of the present invention and the description of the present invention, and is not intended to indicate or imply that the device or component referred to has a specific orientation, is constructed and operated in a specific orientation, and therefore cannot be understood as Limitations of the invention.

Moreover, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" or "second" may include at least one of the features, either explicitly or implicitly. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless specifically defined otherwise.

In the present invention, the terms "installation", "connected", "connected", "fixed" and the like shall be understood broadly, and may be either a fixed connection or a detachable connection, unless explicitly stated and defined otherwise. , or integrated; can be mechanical or electrical connection; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction of two elements, unless otherwise specified Limited. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.

In the present invention, the first feature "on" or "under" the second feature may be a direct contact of the first and second features, or the first and second features may be indirectly through an intermediate medium, unless otherwise explicitly stated and defined. contact. Moreover, the first feature "above", "above" and "above" the second feature may be that the first feature is directly above or above the second feature, or merely that the first feature level is higher than the second feature. The first feature "below", "below" and "below" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely that the first feature level is less than the second feature.

In the description of the present specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means a specific feature described in connection with the embodiment or example. A structure, material or feature is included in at least one embodiment or example of the invention. In the present specification, the schematic representation of the above terms is not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, various embodiments or examples described in the specification, as well as features of various embodiments or examples, may be combined and combined.

Although the embodiments of the present invention have been shown and described, it is understood that the above-described embodiments are illustrative and are not to be construed as limiting the scope of the invention. The embodiments are subject to variations, modifications, substitutions and variations.

Claims

A switching control method for an indoor unit operating mode in a multi-line system, characterized in that the multi-line system comprises an outdoor unit, a flow dividing device and a plurality of indoor units, wherein the outdoor unit comprises a compressor and a four-way valve, The flow dividing device includes a first heat exchange component, a second heat exchange component, an outlet of the first heat exchange flow path of the first heat exchange component, and a first heat exchange flow path of the second heat exchange component a first throttling assembly between the inlets, a portion disposed between an outlet of the first heat exchange passage of the second heat exchange assembly and an inlet of the second heat exchange passage of the second heat exchange assembly a second throttle assembly, a bypass valve disposed between an outlet of the first heat exchange passage of the second heat exchange assembly and a low pressure line of the flow dividing device, and each of the plurality of indoor units The indoor unit corresponds to a heating control valve and a refrigeration control valve, the first throttle assembly includes a first control valve, and the method includes the following steps:

When any one of the plurality of indoor units receives the mode switching instruction, the indoor unit transmits a mode switching instruction to the flow dividing device;

The flow dividing device performs switching control of the heating control valve or the cooling control valve corresponding to the indoor unit according to the received mode switching instruction, and controls the second throttle assembly, the first control valve, and the side Reversing the valve to reduce the pressure difference between the front and rear of the refrigeration control valve or the heating control valve corresponding to the indoor unit, and obtaining the switching flag of the four-way valve, and according to the switching flag of the four-way valve The refrigeration control valve or the heating control valve corresponding to the indoor unit and the four-way valve are controlled.
The method of claim 1 wherein said switching flag of said four-way valve comprises 0 and 1, wherein

When the switching flag of the four-way valve is equal to 0, the operation mode of the multi-line system is switched from the main cooling mode to the pure cooling mode, or the main cooling mode is switched to the main cooling mode, or is switched by the main heating mode. To the pure heating mode, or switch from the main heating mode to the main heating mode;

When the switching flag of the four-way valve is equal to 1, the operation mode of the multi-line system is switched from the main heating mode to the main cooling mode, or the main cooling mode is switched to the main heating mode, or the main cooling mode Switch to the pure heating mode or switch from the main heating mode to the pure cooling mode.
The method according to claim 2, wherein when said flow dividing means determines that said indoor unit is switched from a heating mode to a cooling mode according to the received mode switching command, and said switching flag of said four-way valve is equal to zero When, among them,

The flow dividing device controls the heating control valve corresponding to the indoor unit to be closed after delaying the first preset time, and controls the second throttle assembly and the first control valve to be in an open state, and the delay is After the second preset time, the second throttle assembly and the first control valve are both controlled to be in a closed state, and the corresponding refrigeration control valve of the indoor unit is controlled to be in an open state; or

The flow dividing device controls the heating control valve corresponding to the indoor unit to be turned off after delaying the first preset time, and Controlling that the second throttle assembly and the bypass valve are both in an open state, and after the second predetermined time is delayed, controlling the second throttle assembly and the bypass valve to be in a closed state, and The refrigeration control valve corresponding to the indoor unit is controlled to be in an open state.
The method according to claim 2, wherein when said flow dividing means determines that said indoor unit is switched from a heating mode to a cooling mode according to the received mode switching command, and said switching flag of said four-way valve is equal to one When, among them,

The flow dividing device controls the heating control valve corresponding to the indoor unit to be closed after delaying the first preset time, and controls the second throttle assembly and the first control valve to be in an open state, and the delay is After the preset time, the second throttle assembly and the first control valve are both in a closed state, and the corresponding refrigeration control valve of the indoor unit is controlled to be in an open state, and the four-way valve is controlled to be switched; or,

After delaying the first preset time, the shunting device controls the heating control valve corresponding to the indoor unit to be closed, and controls the second throttling component and the bypass valve to be in an open state, and delays After the second preset time, controlling the second throttle assembly and the bypass valve to be in a closed state, and controlling the corresponding refrigeration control valve of the indoor unit to be in an open state, and controlling the four-way valve to perform Switch.
The method according to claim 2, wherein said shunting device determines that said indoor unit is switched from a cooling mode to a heating mode according to the received mode switching command, and wherein said switching flag of said four-way valve is equal to zero When, among them,

The flow dividing device controls the corresponding refrigeration control valve of the indoor unit to be closed after delaying the first preset time, and controls the second throttle assembly and the first control valve to be in an open state, and delays the second After the preset time, the second throttle assembly and the first control valve are both controlled to be in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be in an open state; or

After delaying the first preset time, the flow dividing device controls the corresponding refrigeration control valve of the indoor unit to be closed, and controls the second throttle assembly and the bypass valve to be in an open state, and the delay time is After the second preset time, the second throttle assembly and the bypass valve are both controlled to be in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be in an open state.
The method according to claim 2, wherein said shunting device determines that said indoor unit is switched from a cooling mode to a heating mode according to the received mode switching command, and wherein said switching flag of said four-way valve is equal to one When, among them,

The flow dividing device controls the corresponding refrigeration control valve of the indoor unit to be closed after delaying the first preset time, and controls the second throttle assembly and the first control valve to be in an open state, and delays the second After the preset time, the second throttle assembly and the first control valve are both controlled to be in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be in an open state, and the four-way valve is controlled to be switched; or,

After delaying the first preset time, the flow dividing device controls the corresponding refrigeration control valve of the indoor unit to be closed, and controls the second throttle assembly and the bypass valve to be in an open state, and the delay time is After the second preset time, the second throttle assembly and the bypass valve are both controlled to be in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be open. Initiating state, and controlling the four-way valve to switch.
A multi-line system, characterized in that it comprises:

An outdoor unit including a compressor and a four-way valve;

Multiple indoor units;

a flow dividing device comprising a first heat exchange component, a second heat exchange component, an outlet of the first heat exchange flow path disposed in the first heat exchange component, and a first exchange of the second heat exchange component a first throttle assembly between the inlets of the heat flow path, an outlet of the first heat exchange passage disposed at the second heat exchange assembly, and an inlet of the second heat exchange passage of the second heat exchange assembly a second throttle assembly, a bypass valve disposed between the outlet of the first heat exchange passage of the second heat exchange assembly and the low pressure line of the flow dividing device, and the plurality of indoor units a heating control valve and a refrigeration control valve corresponding to each indoor unit, the first throttle assembly including a first control valve, wherein when any one of the plurality of indoor units receives a mode switching instruction The indoor unit sends a mode switching instruction to the flow dividing device;

The flow dividing device further includes:

a control module, configured to perform switching control of a heating control valve or a cooling control valve corresponding to the indoor unit according to the received mode switching instruction, and by controlling the second throttle component, the first control The valve and the bypass valve perform pressure relief to reduce a differential pressure between the front and rear of the refrigeration control valve or the heating control valve corresponding to the indoor unit, and obtain a switching flag of the four-way valve, and according to the four-way valve The switching flag bit controls the refrigeration control valve or the heating control valve and the four-way valve corresponding to the indoor unit.
The multiple-line system of claim 7, wherein the switching flag of the four-way valve comprises 0 and 1, wherein

When the switching flag of the four-way valve is equal to 0, the operation mode of the multi-line system is switched from the main cooling mode to the pure cooling mode, or the main cooling mode is switched to the main cooling mode, or is switched by the main heating mode. To the pure heating mode, or switch from the main heating mode to the main heating mode;

When the switching flag of the four-way valve is equal to 1, the operation mode of the multi-line system is switched from the main heating mode to the main cooling mode, or the main cooling mode is switched to the main heating mode, or the main cooling mode Switch to the pure heating mode or switch from the main heating mode to the pure cooling mode.
The multi-line system according to claim 8, wherein the control module determines, according to the received mode switching instruction, that the indoor unit is switched from the heating mode to the cooling mode, and the switching flag of the four-way valve Equal to 0, where,

After delaying the first preset time, the control module controls the heating control valve corresponding to the indoor unit to be closed, and controls the second throttle assembly and the first control valve to be in an open state, and the delay is After the second preset time, the second throttle assembly and the first control valve are both controlled to be in a closed state, and the corresponding refrigeration control valve of the indoor unit is controlled to be in an open state; or

After delaying the first preset time, the control module controls the heating control valve corresponding to the indoor unit to be closed, and controls the second throttle assembly and the bypass valve to be in an open state, and the delay After the second preset time, the second throttle assembly and the bypass valve are both controlled to be in a closed state, and the corresponding refrigeration control valve of the indoor unit is controlled to be in an open state.
The multi-line system according to claim 8, wherein the control module determines, according to the received mode switching instruction, that the indoor unit is switched from the heating mode to the cooling mode, and the switching flag of the four-way valve Equal to 1 when,

After delaying the first preset time, the control module controls the heating control valve corresponding to the indoor unit to be closed, and controls the second throttle assembly and the first control valve to be in an open state, and the delay is After the preset time, the second throttle assembly and the first control valve are both in a closed state, and the corresponding refrigeration control valve of the indoor unit is controlled to be in an open state, and the four-way valve is controlled to be switched; or,

After delaying the first preset time, the control module controls the heating control valve corresponding to the indoor unit to be closed, and controls the second throttle assembly and the bypass valve to be in an open state, and the delay After the second preset time, controlling the second throttle assembly and the bypass valve to be in a closed state, and controlling the corresponding refrigeration control valve of the indoor unit to be in an open state, and controlling the four-way valve to perform Switch.
The multi-line system according to claim 8, wherein the control module determines that the indoor unit is switched from a cooling mode to a heating mode according to the received mode switching instruction, and the switching flag of the four-way valve Equal to 0, where,

After delaying the first preset time, the control module controls the corresponding refrigeration control valve of the indoor unit to be closed, and controls the second throttle assembly and the first control valve to be in an open state, and delays the second After the preset time, the second throttle assembly and the first control valve are both controlled to be in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be in an open state; or

After delaying the first preset time, the control module controls the corresponding refrigeration control valve of the indoor unit to be closed, and controls the second throttle assembly and the bypass valve to be in an open state, and delays the After the second preset time, the second throttle assembly and the bypass valve are both controlled to be in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be in an open state.
The multi-line system according to claim 8, wherein the control module determines that the indoor unit is switched from a cooling mode to a heating mode according to the received mode switching instruction, and the switching flag of the four-way valve Equal to 1 when,

After delaying the first preset time, the control module controls the corresponding refrigeration control valve of the indoor unit to be closed, and controls the second throttle assembly and the first control valve to be in an open state, and delays the second After the preset time, the second throttle assembly and the first control valve are both controlled to be in a closed state, and the heating control valve corresponding to the indoor unit is controlled to be open. Turning on the state, and controlling the four-way valve to switch; or,

After delaying the first preset time, the control module controls the corresponding refrigeration control valve of the indoor unit to be closed, and controls the second throttle assembly and the bypass valve to be in an open state, and delays the After the second preset time, controlling the second throttle assembly and the bypass valve to be in a closed state, and controlling the corresponding heating control valve of the indoor unit to be in an open state, and controlling the four-way valve to perform Switch.