Air conditioning system and control method thereof

Abstract

The application provides an air conditioning system and a control method thereof. The air conditioning system comprises a compressor, a condenser, a first evaporator, a second evaporator, a condensing pipeline and an evaporating pipeline. The condensing pipeline comprises a total condensing main pipeline and parallelly connected first and second condensing branch pipelines. The compressor is connected to the condenser. The condenser is connected to the first and second evaporators through the condensing pipeline. The evaporating pipeline comprises a total evaporating main pipeline and parallelly connected first and second evaporating branch pipelines. The first and second evaporators are both connected to the compressor through the evaporating pipeline. The horizontal height of the inlet of the first condensing branch pipeline is lower than that of the outlet of the first condensing branch pipeline.

Description

Technical Field

[0001] This invention belongs to the technical field of vehicle air conditioning systems, and particularly relates to an air conditioning system and its control method. Background Technology

[0002] With the development of automotive air conditioning systems, multi-evaporator systems have emerged, including evaporators for front air conditioning, rear air conditioning, active battery cooling, and refrigerators. When the front air conditioner (passenger compartment evaporator) is not working and other evaporators are cooling, the refrigerant oil in the air conditioning system circuit can clog the solenoid valve of the front air conditioner. When the front air conditioner needs to cool, the refrigerant oil clogs the front solenoid valve, preventing it from opening and causing the air conditioner to fail to cool. Summary of the Invention

[0003] The purpose of this invention is to provide an air conditioning system and its control method, which aims to solve the technical problem of the solenoid valve of the existing front air conditioner being blocked by refrigerant oil.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, an air conditioning system is provided, comprising a compressor, a condenser, a first evaporator, a second evaporator, a condensing pipe, and an evaporating pipe. The condensing pipe includes a main condensing line, a first condensing branch line, and a second condensing branch line. The inlet of the main condensing line is connected to the outlet of the condenser. The outlet of the main condensing line is connected to the inlet of the first condensing branch line and the inlet of the second condensing branch line via a tee. The outlet of the first condensing branch line is connected to the first evaporator via a first shut-off valve. The outlet of the second condensing branch line is connected to the second evaporator via a second shut-off valve. The evaporating pipe includes a main evaporating line, a first evaporating branch line, and a second evaporating branch line. The inlet of the first evaporating branch line is connected to the outlet of the first evaporating evaporator. The inlet of the second evaporating branch line is connected to the outlet of the second evaporating evaporator. The inlet of the main evaporating line is connected to the outlet of the first evaporating branch line and the outlet of the second evaporating branch line via a tee. The outlet of the main evaporating line is connected to the inlet of the compressor. The outlet of the compressor is connected to the inlet of the condenser.

[0006] The horizontal level of the inlet of the first condensation branch is lower than the horizontal level of the outlet of the first condensation branch.

[0007] In one embodiment of the first aspect, the first shut-off valve includes a housing, a stationary iron core, a moving iron core, a push rod, a piston, and a first elastic element. The housing has a communicating mounting cavity and a flow channel cavity. The inlet of the flow channel cavity is connected to the outlet of the first condensation branch, and the outlet of the flow channel cavity is connected to the inlet of the first evaporator. The stationary iron core is fixedly connected to the mounting cavity. The moving iron core is located on the side of the stationary iron core facing away from the flow channel cavity and is slidably connected to the mounting cavity along the axial direction of the stationary iron core. The stationary iron core has an axially extending first through hole. The push rod slidably passes through the first through hole. The push rod is connected to the moving iron core and abuts against the piston. The piston is slidably connected to the flow channel cavity along the axial direction of the mounting cavity. The first elastic element is disposed between the piston and the cavity wall of the flow channel cavity and is used to provide an elastic force to the piston toward the stationary iron core after the push rod is separated from the piston.

[0008] In one embodiment of the first aspect, the piston has a second through hole axially opened along the stationary core, the second through hole being axially opposite to the first through hole in the stationary core.

[0009] The technical advantages of this invention compared to the prior art are as follows: When only the second evaporator needs to be started, without starting the first evaporator, the first shut-off valve is closed and the second shut-off valve is open. The refrigerant in the condensing pipe enters only the second condensing branch from the main condensing line. Since the refrigerant and refrigeration oil are mixed together in the air conditioning system's piping, the refrigerant in the condensing pipe will cause the refrigeration oil to be pushed into the first condensing branch when it flows through the inlet. By setting the horizontal height of the inlet of the first condensing branch to be lower than the horizontal height of the outlet of the first condensing branch, this air conditioning system can reduce the possibility of the refrigeration oil pushed into the first condensing branch entering the first shut-off valve through the outlet of the first condensing branch. Reducing the amount of refrigeration oil at the inlet of the first shut-off valve also reduces the possibility of the first shut-off valve being blocked by refrigeration oil, thereby ensuring the normal operation of the air conditioning system.

[0010] Secondly, a control method for the air conditioning system is provided, applied to the aforementioned air conditioning system, the control method comprising:

[0011] Upon receiving a control signal to start the first evaporator, the compressor is controlled to start.

[0012] If the first shut-off valve remains open, after the compressor starts, the first shut-off valve is controlled to perform a number of first preset actions. The first preset actions include: controlling the first shut-off valve to close for a first preset duration, and after the first shut-off valve has been closed for the first preset duration, controlling the first shut-off valve to open for a second preset duration.

[0013] After the first shut-off valve has performed the first preset action several times, the first shut-off valve is controlled to remain open.

[0014] In one embodiment of the second aspect, the first preset duration is 0.5s-2s.

[0015] In one embodiment of the second aspect, the second preset duration is 0.5-2 seconds.

[0016] In one embodiment of the second aspect, if the first shut-off valve remains normally closed, after the compressor is started, the first shut-off valve is controlled to perform a number of second preset actions. The second preset actions include: controlling the first shut-off valve to open for a second preset duration, and controlling the first shut-off valve to close for the first preset duration after the first shut-off valve has been open for the second preset duration.

[0017] After the first shut-off valve has performed the preset actions several times, the first shut-off valve is controlled to open.

[0018] In one embodiment of the second aspect, the control method further includes:

[0019] Upon receiving a control signal to start the first evaporator, if the second evaporator is already in operation, the first shut-off valve is opened.

[0020] If the shutdown time of the second evaporator is less than a preset value, then the first shut-off valve is controlled to close for a third preset time.

[0021] After the first shut-off valve has been closed for the third preset time, the first shut-off valve is controlled to open.

[0022] In one embodiment of the second aspect, the preset value is 10s-25s.

[0023] In one embodiment of the second aspect, the third preset duration is greater than or equal to 10s and less than or equal to 25s.

[0024] The technical advantages of this invention compared to existing technologies are as follows: When the air conditioning system is not in use, the first shut-off valve remains open to maintain pressure balance throughout the system. When the first evaporator needs to be started, the driver presses the start button. After receiving the control signal from the start button, the ECU controls the compressor to start and then controls the first shut-off valve to close and then open. During the closing process of the first shut-off valve, a pressure difference is generated between the inside and outside of the first shut-off valve. When the first shut-off valve reopens, the refrigerant oil in the flow channel cavity can flow through the second perforation and the gap between the first perforation and the push rod under the action of the pressure difference into the space on the side of the stationary iron core facing away from the piston. The refrigerant oil on the side of the moving iron core facing away from the stationary iron core is flushed out and flows out through the gap between the first perforation and the push rod and the second perforation, thus forming a circulation path for refrigerant oil in the first shut-off valve. This flushes out the refrigerant oil remaining in the first shut-off valve, achieving the renewal of the refrigerant oil in the first shut-off valve, preventing refrigerant oil near the moving iron core from sticking to the moving iron core, and improving the sensitivity of the moving iron core. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the air conditioning system provided in an embodiment of the present invention;

[0027] Figure 2 This is a partial three-dimensional structural diagram of the air conditioning system provided in an embodiment of the present invention;

[0028] Figure 3 yes Figure 2 Sectional view at point AA;

[0029] Figure 4 yes Figure 2 A three-dimensional structural diagram of the air conditioning system from another perspective;

[0030] Figure 5 This is a flowchart of an air conditioning system control method provided in an embodiment of the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 10. Compressor; 20. Condenser; 30. First evaporator; 40. Second evaporator; 50. First shut-off valve; 501. Mounting cavity; 502. Flow channel cavity; 502a. Flow channel inlet; 502b. Flow channel outlet; 51. Outer shell; 52. Stationary iron core; 520. First perforation; 53. Moving iron core; 54. Push rod; 55. Piston; 550. Second perforation; 56. Second elastic element; 57. First elastic element; 60. Second shut-off valve; 70. Condensing pipe; 71. Main condensing line; 72. First condensing branch; 73. Second condensing branch; 80. Evaporation pipe; 81. Main evaporating line; 82. First evaporating branch; 83. Second evaporating branch; 90. Connector; 901. First inlet; 902. First outlet; 91. Connecting channel; 903. Second inlet; 904. Second outlet. Detailed Implementation

[0033] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0034] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0036] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between 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] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0038] Please see Figure 1 This invention provides an air conditioning system for use in a vehicle. The air conditioning system includes a compressor 10, a condenser 20, a first evaporator 30, a second evaporator 40, a condensing pipe 70, and an evaporating pipe 80. The first evaporator 30 is used to cool the vehicle's passenger compartment; this first evaporator 30 is also called a front evaporator or front air conditioner. The second evaporator 40 is used to cool a single battery; in this case, the second evaporator 40 is also called a battery pack cooler. The second evaporator 40 can also be used to cool the trunk; in this case, the second evaporator 40 is also called a rear evaporator or rear air conditioner. When a refrigerator is installed in the vehicle, the second evaporator 40 can also be used to cool the refrigerator; this is not a limitation. The condenser 20 is connected to the first evaporator 30 and the second evaporator 40 respectively via the condensing pipe 70. The first evaporator 30 and the second evaporator 40 are connected to the compressor 10 via the evaporating pipe 80. The outlet of the compressor 10 is connected to the inlet of the condenser 20. A connecting pipe may also be provided between the outlet of compressor 10 and the inlet of condenser 20. It should be noted that the first evaporator 30 may also be used to cool a single battery, trunk, or refrigerator, and the second evaporator 40 may be used to cool the passenger compartment; there are no restrictions here.

[0039] Please combine Figure 2 The condenser piping 70 includes a main condenser pipe 71, a first condenser branch pipe 72, and a second condenser branch pipe 73. The inlet of the main condenser pipe 71 is connected to the outlet of the condenser 20. The outlet of the main condenser pipe 71 is connected to the inlet of the first condenser branch pipe 72 and the inlet of the second condenser branch pipe 73 via a tee. A first shut-off valve 50 is connected to the inlet of the first evaporator 30. The outlet of the first condenser branch pipe 72 is connected to the first evaporator 30 via the first shut-off valve 50. The outlet of the second condenser branch pipe 73 is connected to the second evaporator 40 via the second shut-off valve 60.

[0040] The evaporation pipeline 80 includes a main evaporation pipeline 81, a first evaporation branch pipeline 82, and a second evaporation branch pipeline 83. The inlet of the first evaporation branch pipeline 82 is connected to the outlet of the first evaporator 30, and the inlet of the second evaporation branch pipeline 83 is connected to the outlet of the second evaporator 40. The inlet of the main evaporation pipeline 81 is connected to the outlet of the first evaporation branch pipeline 82 and the outlet of the second evaporation branch pipeline 83 via a tee. The outlet of the main evaporation pipeline 81 is connected to the inlet of the compressor 10.

[0041] After being compressed by compressor 10, the refrigerant enters condenser 20, where it forms liquid refrigerant under high pressure. This liquid refrigerant is then branched through main condenser 81 to first condenser branch 72 and second condenser branch 73. The refrigerant in first condenser branch 72 passes through first shut-off valve 50 and enters first evaporator 30. First evaporator 30 vaporizes the refrigerant, absorbing heat and achieving cooling. The refrigerant in second condenser branch 73 passes through second shut-off valve 60 and enters second evaporator 40, where it also vaporizes and absorbs heat, achieving cooling. The refrigerant vaporized in first evaporator 30 and second evaporator 40 respectively enter main evaporator 81 through first evaporator branch 82 and second evaporator branch 83, and then enters compressor 10 for compression, continuing the next cycle. When only one of the first evaporator 30 and the second evaporator 40 needs to be started, the shut-off valve connected to the corresponding evaporator can be opened. That is, when only the first evaporator 30 needs to be started, the first shut-off valve 50 is opened and the second shut-off valve 60 is closed. When only the second evaporator 40 needs to be started, the first shut-off valve 50 is closed and the second shut-off valve 60 is opened.

[0042] The horizontal height of the inlet of the first condensing branch 72 is lower than the horizontal height of the outlet of the first condensing branch 72.

[0043] When only the second evaporator 40 needs to be started, without starting the first evaporator 30, the first shut-off valve 50 is closed and the second shut-off valve 60 is open. The refrigerant in the condensing pipe 70 enters the second condensing branch 73 from the main condensing line 71. Since the refrigerant and refrigerant oil are mixed together in the air conditioning system's piping, when the refrigerant in the condensing pipe 70 flows through the inlet of the first condensing branch 72, it will cause the refrigerant oil to be pushed into the first condensing branch 72. By setting the horizontal height of the inlet of the first condensing branch 72 to be lower than the horizontal height of the outlet of the first condensing branch 72, the air conditioning system can reduce the possibility of the refrigerant oil pushed into the first condensing branch 72 entering the first shut-off valve 50 through the outlet of the first condensing branch 72. Reducing the refrigerant oil at the inlet of the first shut-off valve 50 also reduces the possibility of the first shut-off valve 50 being blocked by refrigerant oil, thereby ensuring the normal operation of the air conditioning system.

[0044] Specifically, the air conditioning system also includes a connector 90, which connects the first condensing branch 72, the first evaporating branch 82, and the first evaporator 30. The connector 90 includes a first inlet 901, a first outlet 902, and a connecting channel 91. A first shut-off valve 50 is disposed within the connector 90. The inlet of the first shut-off valve 50 is connected to the first inlet 901 of the connector 90, and the outlet of the first shut-off valve 50 is connected to the first outlet 902 of the connector 90. The connecting channel 91 has a second inlet 903 and a second outlet 904. The outlet of the first condensing branch 72 is connected to the first inlet 901 of the connector 90, the first outlet 902 of the connector 90 is connected to the inlet of the first evaporator 30, the outlet of the first evaporator 30 is connected to the second inlet 903 of the connecting channel 91, and the second outlet 904 of the connecting channel 91 is connected to the inlet of the first evaporating branch 82.

[0045] Optionally, the horizontal height of the inlet of the first evaporation branch 82 is higher than the horizontal height of the outlet of the first evaporation branch 82. In this way, when the first evaporator 30 is not started but the second evaporator 40 is started, the refrigerant oil in the second evaporation branch 83 flows through the outlet of the first evaporation branch 82 into the main evaporation branch 81. The refrigerant oil accumulated in the first evaporation branch 82 will not enter the first evaporator 30 through the inlet of the first evaporation branch 82, and will flow back to the first shut-off valve 50 through the first evaporator 30, further preventing the first shut-off valve 50 from becoming blocked.

[0046] Please see Figure 3 and Figure 4 In some embodiments, the first shut-off valve 50 includes a housing 51, a coil, a stationary iron core 52, a moving iron core 53, a push rod 54, and a piston 55.

[0047] The outer casing 51 has a connected mounting cavity 501 and a flow channel cavity 502. The mounting cavity 501 extends in a straight line, and the extension direction of the mounting cavity 501 is the extension direction of the central axis of the mounting cavity 501. One end of the mounting cavity 501 is closed and the other end is open. The opening of the mounting cavity 501 connects to the cavity wall of the flow channel cavity 502. The flow channel cavity 502 has a flow channel inlet 502a and a flow channel outlet 502b. The flow channel inlet 502a is the inlet of the first shut-off valve 50, which is connected to the first inlet 901 of the connector 90 and is connected to the outlet of the first condensation branch 72. The flow channel outlet 502b is the outlet of the first shut-off valve 50, which is connected to the first outlet 902 of the connector 90 and is connected to the inlet of the first evaporator 30. The flow channel outlet 502b is axially opposite to the opening of the mounting cavity 501.

[0048] The stationary iron core 52 is fixedly connected to the mounting cavity 501 and close to the opening of the mounting cavity 501. The moving iron core 53 is located on the side of the stationary iron core 52 facing away from the flow channel cavity 502 and is slidably connected to the mounting cavity 501 along the axial direction of the stationary iron core 52. The stationary iron core 52 has an axially extending first through hole 520. The push rod 54 passes through the first through hole 520 and is connected to the moving iron core 53. The push rod can slide relative to the stationary iron core 52 in the first through hole 520. The piston 55 is slidably connected to the flow channel cavity 502 along the axial direction of the mounting cavity 501. The piston 55 can move between the starting position and the blocking position. The flow channel inlet 502a and outlet are both located on the side of the piston 55 facing away from the stationary iron core 52. When the piston 55 is in the starting position and the blocking position, it avoids the flow channel inlet 502a. When the piston 55 is in the blocking position, the piston 55 blocks the flow channel outlet 502b. A coil is wound around the outer casing 51, and when energized, it enables the stationary iron core 52 to generate a magnetic attraction. This magnetic attraction causes the moving iron core 53 to slide towards the flow channel cavity 502 until the push rod 54 pushes the piston 55 from the starting position to the blocking position, thus blocking the flow channel outlet 502b. When the coil is de-energized, the magnetic attraction of the stationary iron core 52 disappears, and the piston 55 can move from the blocking position to the starting position under the pressure of the refrigerant in the flow channel cavity 502, allowing the refrigerant to flow out through the flow channel outlet 502b.

[0049] During the process of piston 55 moving from the starting position to the blocking position, the refrigerant oil between the moving iron core 53 and the stationary iron core 52 flows through the gap between the peripheral side of the moving iron core 53 and the cavity wall of the mounting cavity 501 to the side of the moving iron core 53 facing away from the stationary iron core 52. During the process of piston 55 moving from the blocking position to the starting position, the moving iron core 53 moves towards the side facing away from the stationary iron core 52. The refrigerant oil on the side of the moving iron core 53 facing away from the stationary iron core 52 is squeezed by the moving iron core 53 and flows through the gap between the moving iron core 53 and the cavity wall of the mounting cavity 501 to the space between the moving iron core 53 and the stationary iron core 52. Since the refrigerant oil in the mounting cavity 501 generally circulates internally, it may cause the moving iron core 53 to stick to the cavity wall of the mounting cavity 501 when it is not used for a long time, resulting in loss of sensitivity or failure of the first shut-off valve 50.

[0050] Optionally, the first shut-off valve 50 further includes a second elastic element 56. The second elastic element 56 is disposed between the moving iron core 53 and the stationary iron core 52, and is used to apply an elastic force to the moving iron core 53 in a direction away from the stationary iron core 52 when the coil is de-energized. When the moving iron core 53 moves in a direction away from the stationary iron core 52, it can drive the push rod 54 to move in a direction away from the piston 55, so that the piston 55 can move towards the starting position under the pressure of the refrigerant. The elastic force of the second elastic element 56 can increase the force of the moving iron core 53 moving away from the stationary iron core 52, thereby overcoming the adhesion of the refrigerant oil and improving the sensitivity of the moving iron core 53.

[0051] Optionally, the first shut-off valve 50 further includes a first elastic element 57, which is disposed between the piston 55 and the cavity wall of the flow channel cavity 502. The first elastic element 57 provides an elastic force to the piston 55 to move towards the stationary iron core 52 after the push rod 54 separates from the piston 55. The first elastic element 57 enables rapid reset of the piston 55, preventing it from becoming stuck in the flow channel cavity 502 due to the viscosity of the refrigerant oil. The elastic force of the first elastic element 57 increases the force by which the piston 55 moves towards the stationary iron core 52. The piston 55 can push the moving iron core 53 towards the side away from the stationary iron core 52 via the push rod 54, thereby overcoming the adhesion of the refrigerant oil and improving the sensitivity of the moving iron core 53.

[0052] Optionally, the piston 55 has a second through-hole 550 axially formed along the stationary iron core 52, with the second through-hole 550 and the first through-hole 520 axially opposite each other in the stationary iron core 52. When the piston 55 is in the initial position, the second through-hole 550 is connected to the first through-hole 520. Thus, during the process of the piston 55 moving from the initial position to the blocked position, the refrigerant oil in the flow channel cavity 502 can flow into the space between the piston 55 and the stationary iron core 52 through the second through-hole 550. During the process of the piston 55 moving from the blocked position to the initial position, the refrigerant oil between the piston 55 and the stationary iron core 52 flows out through the flow channel outlet 502b after passing through the second through-hole 550.

[0053] During the above process, some refrigerant oil will enter the side of the stationary iron core 52 opposite to the piston 55 through the gap between the push rod 54 and the hole wall of the first perforation 520. Some refrigerant oil will also flow to the piston 55 through the gap between the push rod 54 and the hole wall of the first perforation 520, and then flow out through the second perforation 550 on the piston 55. This will refresh the refrigerant oil in the mounting cavity 501 and prevent the refrigerant oil from sticking in the first shut-off valve 50 for a long time.

[0054] In some embodiments, the air conditioning system may further include a third evaporator, which is connected in parallel with the first evaporator 30 and the second evaporator 40. In this case, the first evaporator 30, the second evaporator 40 and the third evaporator may be the front air conditioner, the rear air conditioner and the single battery cooler, respectively.

[0055] This invention also provides a control method for an air conditioning system, applied to the air conditioning system of a vehicle. Specifically, this control method is used to control the air conditioning system in a vehicle.

[0056] Please see Figure 5 The control method of the air conditioning system includes:

[0057] Upon receiving the control signal to start the first evaporator 30, the compressor 10 is started.

[0058] If the first shut-off valve 50 remains open, after the compressor 10 starts, the first shut-off valve 50 is controlled to perform a number of first preset actions. The first preset actions include: controlling the first shut-off valve 50 to close for a first preset duration, and after the first shut-off valve 50 is closed for a first preset duration, controlling the first shut-off valve 50 to open for a second preset duration.

[0059] After the first shut-off valve 50 has performed a number of first preset actions, the first shut-off valve 50 is controlled to remain open.

[0060] When the air conditioning system is not in use, the first shut-off valve 50 remains open to keep the pressure in the entire system balanced. When the first evaporator 30 needs to be started, the driver presses the start button. After receiving the control signal from the start button, the ECU controls the compressor 10 to start, and then controls the first shut-off valve 50 to close and then open. During the closing process of the first shut-off valve 50, a pressure difference is generated between the inside and outside of the first shut-off valve 50. When the first shut-off valve 50 reopens, the refrigerant oil in the flow channel cavity 502 can flow through the second perforation 550 and the gap between the first perforation 520 and the push rod 54 under the action of the pressure difference into the space on the side of the stationary iron core 52 facing away from the piston 55. The refrigerant oil on the side of the moving iron core 53 facing away from the stationary iron core 52 is flushed out and flows out through the gap between the first perforation 520 and the push rod 54 and the second perforation 550, so that a circulation path of refrigerant oil is formed in the first shut-off valve 50, thereby flushing out the refrigerant oil remaining in the first shut-off valve 50, realizing the renewal of the refrigerant oil in the first shut-off valve 50, preventing the refrigerant oil near the moving iron core 53 from sticking to the moving iron core 53, and improving the sensitivity of the moving iron core 53.

[0061] It should be noted that when the first shut-off valve 50 performs the first preset action, the compressor 10 can maintain a normal speed, such as 1000 rpm.

[0062] Optionally, the first preset duration is 0.5s-2s. If the closing time of the first shut-off valve 50 is too short, the pressure difference may not be enough to flush out the refrigerant oil in the mounting cavity 501. If the closing time of the first shut-off valve 50 is too long, the seal of the first shut-off valve 50 may be damaged or the air conditioning system may operate unstablely.

[0063] Optionally, the second preset duration is 1-2 seconds. If the opening duration of the first shut-off valve 50 is too short, the refrigerant oil remaining in the mounting cavity 501 may not be completely circulated out before being flushed back into the mounting cavity 501 by the refrigerant oil brought by the closing of the first shut-off valve 50 in a new round. If the opening duration of the first shut-off valve 50 is too long, it may cause the normal operation of the first evaporator 30 to be interrupted, affecting the stable and continuous operation of the first evaporator 30.

[0064] In this embodiment, the first shut-off valve 50 can be controlled to perform one or two first preset actions. After the first shut-off valve 50 is opened for the last time, it can be kept open to ensure the stable operation of the first evaporator 30.

[0065] Please see Figure 5 In some embodiments, if the first shut-off valve 50 remains normally closed, such as when the second evaporator 40 is working for a long time and the first evaporator 30 is not working, the first shut-off valve 50 is normally closed and the compressor 10 is always running. If it is necessary to start the first evaporator 30 under these circumstances, after the compressor 10 starts, the first shut-off valve 50 is controlled to perform a number of second preset actions. The second preset actions include: controlling the first shut-off valve 50 to open for a second preset duration; after the first shut-off valve 50 is open for the second preset duration, controlling the first shut-off valve 50 to close for the first preset duration; and after the first shut-off valve 50 has performed a number of preset actions, controlling the first shut-off valve 50 to open.

[0066] When the first evaporator 30 needs to be started, the driver presses the start button. After receiving the control signal from the start button, the ECU controls the first shut-off valve 50 to open, close, and open again. The number of times the second preset action is performed is the number of times the first shut-off valve 50 is closed. Since the first shut-off valve 50 is always in a normally closed state during the long-term operation of the second evaporator 40, the pressure difference on both sides of the first shut-off valve 50 is large. At this time, the refrigerant oil in the first condenser pipe 70 will accumulate at the inlet of the first shut-off valve 50. When the first shut-off valve 50 is opened for the first time, the refrigerant oil entering the mounting cavity 501 has a high concentration and high viscosity, and is easy to stick to the moving iron core 53. Therefore, by performing the second preset action several times, a pressure difference can be generated again when the first shut-off valve 50 is closed to refresh the refrigerant oil in the mounting cavity 501, so that the concentration of the refrigerant oil in the mounting cavity 501 decreases, thereby reducing the possibility of the refrigerant oil in the mounting cavity 501 sticking to the moving iron core 53 and improving the sensitivity of the moving iron core 53.

[0067] In this embodiment, the first shut-off valve 50 can be controlled to perform one or two second preset actions, and then the first shut-off valve 50 can be controlled to remain in the normally open state to achieve stable operation of the first evaporator 30.

[0068] Please see Figure 5 In some embodiments, the control method further includes:

[0069] Upon receiving a control signal to start the first evaporator 30, if the second evaporator 40 is in operation, the first shut-off valve 50 is opened.

[0070] If the shutdown time of the second evaporator 40 is less than the preset value, then the first shut-off valve 50 is controlled to close for a third preset time.

[0071] After the first shut-off valve 50 has been closed for a third preset period, the first shut-off valve 50 is opened.

[0072] Understandably, if the second evaporator 40 has just stopped operating when the first evaporator 30 is started, the first shut-off valve 50 is delayed in opening. Then, the first shut-off valve 50 performs several second preset actions before finally opening. This is because there is a pressure difference across the first shut-off valve 50 immediately after the second evaporator 40 stops operating. If the first shut-off valve 50 is suddenly opened, high-concentration refrigerant oil will enter the mounting cavity 501. After a certain delay, the pressure difference across the first shut-off valve 50 decreases, allowing some refrigerant oil at the inlet of the second shut-off valve 60 to flow back, thus reducing the concentration of refrigerant oil at the inlet of the first shut-off valve 50. Therefore, opening the first shut-off valve 50 after the first shut-off valve 50 has been closed for a third preset time reduces the concentration of refrigerant oil entering the first shut-off valve 50, thereby reducing the possibility of the moving iron core 53 being stuck by refrigerant oil.

[0073] The phrase "the second evaporator 40 has just stopped operating" refers to a shutdown time of less than 25 seconds, which is the preset value of 10-25 seconds. Within this preset value, the pressure difference across the first shut-off valve 50 is relatively large, requiring this control method to delay the opening of the first shut-off valve 50.

[0074] Optionally, the third preset duration is greater than or equal to 10 seconds and less than or equal to 25 seconds. That is, when the first shut-off valve 50 is delayed by 10-25 seconds before opening, the refrigerant oil concentration at the inlet of the first shut-off valve 50 can be guaranteed to be low. If the duration is too short, the refrigerant oil concentration at the inlet of the first shut-off valve 50 cannot be reduced to a low level; if the duration is too long, it may damage the seal of the first shut-off valve 50 or cause instability in the air conditioning system.

[0075] It should be noted that when the shutdown time of the second evaporator is greater than 25 seconds, it indicates that the first shut-off valve is in the normally open state.

[0076] The above descriptions are merely several specific embodiments of the present invention, and only specifically describe the technical principles of the present invention. These descriptions are only for explaining the principles of the present invention and should not be construed as limiting the scope of protection of the present invention in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention, as well as other specific embodiments of the present invention that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of the present invention.

Claims

1. An air conditioning system, characterized by, The system includes a compressor, a condenser, a first evaporator, a second evaporator, condensing piping, and evaporating piping. The condensing piping includes a main condensing line, a first condensing branch line, and a second condensing branch line. The inlet of the main condensing line is connected to the outlet of the condenser. The outlet of the main condensing line is connected to the inlet of the first condensing branch line and the inlet of the second condensing branch line via a tee. The outlet of the first condensing branch line is connected to the first evaporator via a first shut-off valve, and the outlet of the second condensing branch line is connected to the second evaporator via a second shut-off valve. The evaporating piping includes a main evaporating line, a first evaporating branch line, and a second evaporating branch line. The inlet of the first evaporating branch line is connected to the outlet of the first evaporating evaporator, and the inlet of the second evaporating branch line is connected to the outlet of the second evaporating evaporator. The inlet of the main evaporating line is connected to the outlet of the first evaporating branch line and the outlet of the second evaporating branch line via a tee. The outlet of the main evaporating line is connected to the inlet of the compressor, and the outlet of the compressor is connected to the inlet of the condenser. The horizontal level of the inlet of the first condensation branch is lower than the horizontal level of the outlet of the first condensation branch.

2. The air conditioning system of claim 1, wherein, The first shut-off valve includes a housing, a stationary iron core, a moving iron core, a push rod, a piston, and a first elastic element. The housing has a connected mounting cavity and a flow channel cavity. The inlet of the flow channel cavity is connected to the outlet of the first condensation branch, and the outlet of the flow channel cavity is connected to the inlet of the first evaporator. The stationary iron core is fixedly connected to the mounting cavity. The moving iron core is located on the side of the stationary iron core facing away from the flow channel cavity and is slidably connected to the mounting cavity along the axial direction of the stationary iron core. The stationary iron core has an axially extending first through hole. The push rod slidably passes through the first through hole. The push rod is connected to the moving iron core and abuts against the piston. The piston is slidably connected to the flow channel cavity along the axial direction of the mounting cavity. The first elastic element is disposed between the piston and the cavity wall of the flow channel cavity and is used to provide an elastic force to the piston moving towards the stationary iron core after the push rod is separated from the piston.

3. The air conditioning system of claim 2, wherein, The piston has a second through hole that is axially opened along the stationary iron core, and the second through hole is axially opposite to the first through hole in the stationary iron core.

4. The control method of the air conditioning system according to any one of claims 1 to 3, wherein The control method includes: Upon receiving a control signal to start the first evaporator, the compressor is controlled to start. If the first shut-off valve remains open, after the compressor starts, the first shut-off valve is controlled to perform a number of first preset actions. The first preset actions include: controlling the first shut-off valve to close for a first preset duration, and after the first shut-off valve has been closed for the first preset duration, controlling the first shut-off valve to open for a second preset duration. After the first shut-off valve has performed the first preset action several times, the first shut-off valve is controlled to remain open.

5. The control method according to claim 4, characterized by, The first preset duration is 0.5s-2s.

6. The control method according to claim 4, characterized by, The second preset duration is 0.5-2 seconds.

7. The control method according to claim 4, characterized by, If the first shut-off valve remains normally closed, after the compressor starts, the first shut-off valve is controlled to perform a number of second preset actions. The second preset actions include: controlling the first shut-off valve to open for a second preset duration, and controlling the first shut-off valve to close for the first preset duration after the first shut-off valve has been open for the second preset duration. After the first shut-off valve has performed the preset actions several times, the first shut-off valve is controlled to open.

8. The control method according to claim 4, characterized by, The control method further includes: Upon receiving a control signal to start the first evaporator, if the second evaporator is already in operation, the first shut-off valve is opened. If the shutdown time of the second evaporator is less than a preset value, then the first shut-off valve is controlled to close for a third preset time. After the first shut-off valve has been closed for the third preset time, the first shut-off valve is controlled to open.

9. The control method as described in claim 8, characterized in that, The preset value is 10s-25s.

10. The control method as described in claim 8, characterized in that, The third preset duration is greater than or equal to 10s and less than or equal to 25s.

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