Vehicle-mounted air conditioning system and working method

Abstract

The vehicle-mounted air conditioning system comprises a compressor, a four-way valve, an indoor heat exchanger, an expansion valve and an outdoor heat exchanger which are connected through pipelines, an outlet of the compressor is connected with a first connector of a three-way valve through a pipeline, and a third connector of the three-way valve is connected with one connector of the four-way valve through a pipeline; a second interface of the three-way valve is sequentially connected with an electromagnetic valve and a high-pressure storage tank through pipelines; in the starting stage, a refrigerant in the high-pressure storage tank passes through the electromagnetic valve and a second connector and a third connector of the three-way valve and then sequentially passes through the outdoor heat exchanger, the expansion valve, the indoor heat exchanger and the four-way valve to reach the compressor. In the shutdown stage, the refrigerant in the pipeline flows into the high-pressure storage tank through the first connector and the second connector of the three-way valve and the electromagnetic valve under the power of the compressor. Most refrigerants in the air conditioning system are stored in the high-pressure storage tank, the air conditioning system and the high-pressure storage tank are isolated through the electromagnetic valve, the air conditioning system is kept at the low pressure level, and the probability of leakage is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle air conditioners, and particularly to a vehicle air conditioning system and a working method thereof. Background Art

[0002] The statements in this part only provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] R744 refrigerant, that is, carbon dioxide refrigerant, has been gradually applied in vehicle air conditioning systems because it does not damage the ozone layer and has minimal impact on the environment. Since the main component of R744 refrigerant is carbon dioxide, which can react with water to form carbonic acid, special attention needs to be paid to maintaining dryness in the air conditioning system to prevent moisture from entering and causing corrosion of metal pipelines.

[0004] In current vehicle air conditioners, the sealing of each interface between pipelines / components is mainly achieved by movable connections such as threads or ferrule joints. Under long-term vibration conditions of the interfaces, it is difficult to avoid refrigerant leakage. According to relevant statistics, in the R744 air conditioning system of a certain passenger car, the refrigerant can exceed the leakage standard within 1 - 3 months, resulting in serious deterioration of the performance of the air conditioning system and bringing many inconveniences to end-users. Summary of the Invention

[0005] In order to solve the technical problems in the above background art, the present invention provides a vehicle air conditioning system and a working method thereof. A high-pressure storage tank with a root valve is connected to the vehicle air conditioning system. When the system stops, the vast majority of the refrigerant is inhaled into the high-pressure storage tank for storage, reducing the refrigerant pressure in the system and the leakage amount and leakage probability of the refrigerant in the system. When the system starts, the refrigerant is led out from the high-pressure storage tank to participate in the refrigeration / heating cycle.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The first aspect of the present invention provides a vehicle air conditioning system, including a compressor, a four-way valve, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger connected by pipelines. The outlet of the compressor is connected to the first interface of a three-way valve through a pipeline. The third interface of the three-way valve is connected to one of the interfaces of the four-way valve through a pipeline. The second interface of the three-way valve is connected to a high-pressure storage tank through a pipeline connecting an electromagnetic valve in sequence.

[0008] During the startup stage, the refrigerant in the high-pressure storage tank passes through the electromagnetic valve and the second and third interfaces of the three-way valve, and then passes through the outdoor heat exchanger, the expansion valve, the indoor heat exchanger, and the four-way valve in sequence, and reaches the compressor.

[0009] During the shutdown stage, the refrigerant in the pipeline, under the power of the compressor, flows into the high-pressure storage tank through the first and second interfaces of the three-way valve and the electromagnetic valve.

[0010] As a further implementation, the a interface of the four-way valve is connected to the third interface of the three-way valve through a pipeline. The b interface of the four-way valve is sequentially connected to the outdoor heat exchanger, the expansion valve, the indoor heat exchanger, and the d interface of the four-way valve through pipelines. The c interface of the four-way valve is connected to the compressor inlet through a pipeline.

[0011] As a further implementation, a pre-cooler is provided on the pipeline between the solenoid valve and the high-pressure storage tank.

[0012] As a further implementation, a first pressure sensor is provided on the high-pressure storage tank to monitor the pressure value of the high-pressure storage tank. A second pressure sensor is provided on the pipeline between the four-way valve and the indoor heat exchanger to obtain the refrigerant pressure entering the indoor heat exchanger. A third pressure sensor is provided on the pipeline between the four-way valve and the outdoor heat exchanger to obtain the refrigerant pressure entering the outdoor heat exchanger.

[0013] The second aspect of the present invention provides a working method for a vehicle-mounted air-conditioning system, including two cycles: indoor refrigeration and indoor heating. During the indoor refrigeration cycle, the working method of the vehicle-mounted air-conditioning system includes the following steps:

[0014] During the indoor refrigeration cycle, the a interface and the b interface of the four-way valve are connected, and at the same time, the c interface and the d interface are connected.

[0015] In the startup stage: the compressor is turned off, and the second and third interfaces of the three-way valve are connected. The solenoid valve is opened, the fan of the indoor heat exchanger is turned on, and the opening degree of the expansion valve is adjusted. Using the pressure difference, the refrigerant flows out from the high-pressure storage tank and sequentially passes through the outdoor heat exchanger, the expansion valve, and the indoor heat exchanger.

[0016] In the normal operation stage: the solenoid valve is closed, the high-pressure storage tank remains in a state of being cut off from the main circulation loop, and the main circulation loop of the air conditioner operates normally.

[0017] In the shutdown stage: the solenoid valve is opened, the three-way valve is switched to the state where the first interface and the second interface are connected, and the opening degree of the expansion valve is adjusted to the maximum. The residual refrigerant in the air-conditioning pipeline and the heat exchanger is cooled by the pre-cooler under the power of the compressor and stored in the high-pressure storage tank in a supercritical pressure state.

[0018] As a further implementation, during the indoor refrigeration cycle, in the startup stage: when the difference between the pressure of the high-pressure storage tank and the refrigerant pressure of the outdoor heat exchanger is less than the first threshold, and the difference between the refrigerant pressure of the outdoor heat exchanger and the refrigerant pressure of the indoor heat exchanger is less than the second threshold, the solenoid valve is closed, the three-way valve is switched to the state where the first and third interfaces are connected, the compressor is started, and the air-conditioning system is started.

[0019] As a further implementation, during the indoor refrigeration cycle, in the shutdown stage: when the difference between the refrigerant pressure of the outdoor heat exchanger and the refrigerant pressure of the indoor heat exchanger is less than the third threshold, and the numerical value of the refrigerant pressure of the outdoor heat exchanger is lower than the fourth threshold, the three-way valve switches to connect the first and third interfaces, the solenoid valve closes, the compressor closes, and the system shuts down.

[0020] As a further implementation, during the indoor heating cycle, a working method of the vehicle air conditioning system includes the following steps;

[0021] During the indoor heating cycle, the a interface and the d interface of the four-way valve are connected, and at the same time, the b interface and the c interface are connected;

[0022] In the startup stage: the compressor is off, the second and third interfaces of the three-way valve are connected; the solenoid valve is open, the fan of the indoor heat exchanger is on, the opening of the expansion valve is adjusted, and the refrigerant flows out from the high-pressure storage tank under the drive of the pressure difference, and sequentially passes through the outdoor heat exchanger, the expansion valve and the indoor heat exchanger;

[0023] In the normal operation stage: the solenoid valve is closed, the high-pressure storage tank remains disconnected from the main circulation loop, and the main circulation loop of the air conditioner operates normally;

[0024] In the shutdown stage: the solenoid valve is open, the three-way valve switches to the state where the first interface and the second interface are connected, and the opening of the expansion valve is adjusted to the maximum; the residual refrigerant in the air conditioning pipeline and the heat exchanger is cooled by the precooler under the power action of the compressor and stored in the high-pressure storage tank in a supercritical pressure state.

[0025] As a further implementation, during the indoor heating cycle, in the startup stage: when the difference between the pressure of the high-pressure storage tank and the refrigerant pressure of the indoor heat exchanger is less than the first threshold, and the difference between the refrigerant pressure of the indoor heat exchanger and the refrigerant pressure of the outdoor heat exchanger is less than the second threshold, the solenoid valve is closed, the three-way valve switches to connect the first and third interfaces, the compressor starts, and the air conditioning system starts.

[0026] As a further implementation, during the indoor heating cycle, in the shutdown stage: when the difference between the refrigerant pressure of the indoor heat exchanger and the refrigerant pressure of the outdoor heat exchanger is less than the third threshold, and the numerical value of the refrigerant pressure of the indoor heat exchanger is lower than the fourth threshold, the three-way valve switches to connect the first and third interfaces, the solenoid valve is closed, the compressor is closed, and the system shuts down.

[0027] Compared with the prior art, the above one or more technical solutions have the following beneficial effects:

[0028] 1. Connect a high-pressure storage tank with a root valve (solenoid valve) to the vehicle air conditioning system. During the system shutdown phase, utilize the existing refrigerant suction capacity of the compressor to suck and compress the vast majority of the refrigerant inside the air conditioning system into the high-pressure storage tank, and isolate the air conditioning system from the high-pressure storage tank by the solenoid valve, thereby maintaining the air conditioning system at a relatively low pressure level, reducing the pressure difference between the air conditioning and the environment, and lowering the probability of leakage. During startup, utilize the existing pressure in the high-pressure storage tank to first deliver the refrigerant into the pipeline of the system, and after reaching the set pressure, then start the compressor to begin the refrigeration or heating cycle.

[0029] 2. The solenoid valve is used to isolate the air conditioning system from the high-pressure storage tank. Therefore, it is preferable to weld between the high-pressure storage tank and the solenoid valve. Welding can be used as a pre-process, making the leakage risk of the high-pressure storage tank to the environment extremely small, and at the same time not affecting the overall assembly of the vehicle air conditioning.

[0030] 3. By setting a pressure monitoring module to monitor the pressure at different positions in the air conditioning system, determine the residual degree of the refrigerant in the pipeline, and by setting reasonable thresholds, ensure that the refrigerant maintains a low pressure during the shutdown phase and maintains a sufficient amount of refrigerant during the normal operation phase, which is conducive to the inspection and maintenance of the air conditioning system when refrigerant leaks. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0032] Figure 1 is a schematic structural diagram of a vehicle air conditioning system provided by one or more embodiments of the present invention;

[0033] Figure 2 is a schematic diagram of the working process during the startup of a vehicle air conditioning system provided by one or more embodiments of the present invention;

[0034] Figure 3 is a schematic diagram of the working process during the shutdown of a vehicle air conditioning system provided by one or more embodiments of the present invention.

[0035] In the figure: 1 - compressor; 2 - three-way valve; 3 - four-way valve; 4 - pre-cooler; 5 - high-pressure storage tank; 6 - outdoor heat exchanger; 7 - expansion valve; 8 - indoor heat exchanger; 9 - solenoid valve; 101 - first pressure sensor; 102 - second pressure sensor; 103 - third pressure sensor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The present invention will be further described below in conjunction with the drawings and embodiments.

[0037] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0038] It should be noted that the terms herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0039] Term Explanation:

[0040] R744 refrigerant, also known as carbon dioxide refrigerant, is an environmentally friendly and efficient refrigerant that generally does not undergo chemical reactions under normal conditions. It can react with water to form carbonic acid. Therefore, special attention needs to be paid to keeping it dry in the refrigeration system to prevent moisture from entering and causing corrosion of metal pipelines.

[0041] Vehicle air conditioning system, an air conditioning system installed on a motor vehicle, which realizes refrigeration and heating through the circulating flow of a refrigerant (also known as a refrigerant) in the system.

[0042] As introduced in the background technology, the connections between the pipelines / components of the vehicle air conditioning system mainly rely on threaded or ferrule movable connections to achieve the sealing of each interface. Under long-term vibration conditions of the interface, it is difficult to avoid the leakage of the refrigerant. When leakage occurs, the performance of the air conditioning system deteriorates, bringing many inconveniences to the end users.

[0043] Therefore, the following embodiments provide a vehicle air conditioning system and a working method. A high-pressure storage tank with a root valve is connected to the vehicle air conditioning system. When the system is shut down, the vast majority of the refrigerant is sucked into the high-pressure storage tank for storage, reducing the refrigerant pressure in the system and the leakage amount and leakage probability of the refrigerant in the system. When the system is started, the refrigerant is led out from the high-pressure storage tank to participate in the refrigeration / heating cycle.

[0044] Embodiment 1:

[0045] As Figure 1 shown, a vehicle air conditioning system includes a compressor, a four-way valve, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger connected by pipelines. The outlet of the compressor is connected to the first interface of a three-way valve through a pipeline. The third interface of the three-way valve is connected to one of the interfaces of the four-way valve through a pipeline. The second interface of the three-way valve is connected to a solenoid valve and a high-pressure storage tank through pipelines in sequence;

[0046] In the startup stage, the refrigerant in the high-pressure storage tank passes through the solenoid valve and the second and third interfaces of the three-way valve, and then successively passes through the outdoor heat exchanger, the expansion valve, the indoor heat exchanger, and the four-way valve to reach the compressor;

[0047] In the shutdown stage, the refrigerant in the pipeline flows into the high-pressure storage tank under the power of the compressor through the first and second interfaces of the three-way valve and the solenoid valve.

[0048] In this embodiment, the system includes a compressor 1, a three-way valve 2, a four-way valve 3, a pre-cooler 4, a high-pressure storage tank 5, an outdoor heat exchanger 6, an expansion valve 7, an indoor heat exchanger 8, and a solenoid valve 9.

[0049] The outlet of the compressor 1 is connected to the first interface of the three-way valve 2 through a pipeline. The second interface of the three-way valve 2 is successively connected to the pre-cooler 4, the solenoid valve 9, and the high-pressure storage tank 5 through pipelines. The third interface of the three-way valve 2 is connected to the a interface of the four-way valve 3 through a pipeline;

[0050] The b interface of the four-way valve 3 is successively connected to the outdoor heat exchanger 6, the expansion valve 7, the indoor heat exchanger 8, and the d interface of the four-way valve 3 through pipelines. The c interface of the four-way valve 3 is connected to the inlet of the compressor 1 through a pipeline.

[0051] As a further implementation, the high-pressure storage tank 5 is used to store a set amount of refrigerant in the air-conditioning system during the shutdown stage to slow down the leakage of high-pressure refrigerant to the environment.

[0052] As a further implementation, the high-pressure storage tank 5 has a pressure stabilizing function. An airbag buffer structure can be adopted inside it, or a variable volume pressure regulating structure with a movable piston and an adjusting spring can be adopted.

[0053] As a further implementation, the connection form between the high-pressure storage tank 5 and the solenoid valve 9 is welding, making the solenoid valve 9 the root valve of the high-pressure storage tank 5. The welding method can ensure that the connection point between the high-pressure storage tank 5 and the solenoid valve 9 is not prone to refrigerant leakage, ensuring that the refrigerant can be properly stored in the high-pressure storage tank 5.

[0054] As a further implementation, the system is provided with a pressure monitoring module, including a first pressure sensor 101, a second pressure sensor 102, and a third pressure sensor 103. The first pressure sensor is used to monitor the pressure value of the high-pressure storage tank 5. The second pressure sensor is placed between the four-way valve 3 and the indoor heat exchanger 6, and the third pressure sensor is placed between the four-way valve 3 and the outdoor heat exchanger 8.

[0055] As a further implementation, the refrigerant of the system is carbon dioxide, a carbon dioxide-based mixed working fluid.

[0056] As a further implementation, both the indoor heat exchanger 8 and the outdoor heat exchanger 6 are matched with fans.

[0057] In this embodiment, the system has a refrigeration / heating function, which is achieved by switching different interfaces through the four-way valve 3 to generate different refrigerant circulation paths in the system.

[0058] In this embodiment, taking the refrigeration cycle as an example, in the refrigeration cycle, the ab and cd of the four-way valve 3 are connected;

[0059] As Figure 2 shown, in the startup stage: the compressor 1 is closed, and the second and third interfaces of the three-way valve 2 are connected; the solenoid valve 9 is opened, the opening degree of the expansion valve 7 is adjusted, the fan of the indoor heat exchanger 8 is turned on, and the high-pressure refrigerant flows out from the high-pressure storage tank 5 under the drive of the pressure difference, passes through the ab interface of the four-way valve 3, the outdoor heat exchanger 6, the expansion valve 7 and the indoor heat exchanger 8 in sequence, and returns to the compressor 1 through the cd interface of the four-way valve 3. During this period, the pressure value is read by the pressure monitoring module. When the difference between the first pressure sensor 101 and the third pressure sensor 103 is less than the set first threshold P1, and the difference between the third pressure sensor 103 and the second pressure sensor 102 is less than the set second threshold P2, the solenoid valve 9 is closed, the three-way valve 2 is switched to connect the first and third interfaces, the compressor 1 is started, and the air-conditioning system is started.

[0060] In the normal operation stage: the solenoid valve 9 is closed, the high-pressure storage tank 5 remains in a state of being cut off from the main circulation loop, and the air-conditioning main circulation loop operates normally; the refrigerant is driven by the compressor 1, passes through the ab interface of the four-way valve 3 to reach the outdoor heat exchanger 6, releases the carried heat to the external environment, obtains medium-temperature high-pressure refrigerant, then passes through the expansion valve 7 to reach the indoor heat exchanger 8, and the medium-temperature high-pressure refrigerant is converted into low-temperature medium-pressure refrigerant through the expansion valve 7. At the same time, the indoor temperature is reduced by using the heat exchange effect of the indoor heat exchanger 8 to achieve refrigeration, and the refrigerant after absorbing heat returns to the compressor 1 through the cd interface of the four-way valve 3 to participate in the next cycle.

[0061] As Figure 3 shown, in the shutdown stage: the solenoid valve 9 is opened, the three-way valve 2 is switched to the state where the first interface is connected to the second interface, and the opening degree of the expansion valve 7 is adjusted to the maximum; the residual refrigerant in the air-conditioning pipeline and heat exchanger is sucked and compressed by the compressor 1, and is stored in the high-pressure storage tank 5 in a supercritical pressure state after being cooled by the pre-cooler 4; during this period, the pressure value is read by the pressure monitoring module. When the difference between the third pressure sensor 103 and the second pressure sensor 102 is less than the third threshold P3, and the value of the third pressure sensor 103 is lower than the fourth threshold P4, the three-way valve 2 is switched to connect the first and third interfaces, the solenoid valve 9 is closed, and the connection between the high-pressure storage tank 5 and the main loop of the air-conditioning system is cut off; the compressor 1 is turned off, and the system shuts down.

[0062] As a further implementation, the circulation mode of the refrigerant is changed through the switching action of the four-way valve 3 to achieve a heating cycle. During the heating cycle, the ad interface of the four-way valve 3 is connected and the bc interface is connected, so that the compressed refrigerant first passes through the indoor heat exchanger 8 to release heat, then passes through the expansion valve and the outdoor heat exchanger 6 to absorb heat, and finally returns to the compressor 1. Its working principle is the same as that of the refrigeration cycle, except that during the normal operation stage, the order in which the refrigerant enters the two heat exchangers is different, while during the startup stage and the shutdown stage, the process of the refrigerant entering and leaving the high-pressure storage tank is the same.

[0063] The above system connects a high-pressure storage tank with a root valve (solenoid valve) to the vehicle air-conditioning system. During the shutdown stage of the system, it can utilize the existing refrigerant suction capacity of the compressor to suck and store most of the refrigerant inside the air-conditioning system into the high-pressure storage tank, and the solenoid valve isolates the connection between the air-conditioning system and the high-pressure storage tank, thereby maintaining the air-conditioning system at a relatively low pressure level, reducing the pressure difference between the air-conditioning and the environment, and reducing the probability of leakage. The high-pressure storage tank and the solenoid valve are welded, so the leakage risk of the high-pressure storage tank to the environment is extremely small. Welding can be used as a pre-process without affecting the overall assembly of the automotive air-conditioning.

[0064] By setting a pressure monitoring module, based on the pressure monitoring at different positions, the residual degree of the refrigerant in the pipeline is determined. By setting reasonable thresholds, it is ensured that the refrigerant maintains a low pressure during the shutdown stage and sufficient refrigerant volume during the normal operation stage.

[0065] Embodiment 2:

[0066] A working method of a vehicle air-conditioning system includes two cycles: indoor refrigeration and indoor heating.

[0067] Indoor refrigeration: The ab of the four-way valve is connected and the cd is connected;

[0068] Startup stage: The compressor is turned off, and the second and third interfaces of the three-way valve are connected; the solenoid valve is opened, the opening degree of the expansion valve is adjusted, the fan of the indoor heat exchanger is turned on, and the high-pressure refrigerant flows out of the high-pressure storage tank under the drive of the pressure difference, passes through the outdoor heat exchanger, the expansion valve and the indoor heat exchanger in sequence. The pressure monitoring module reads the pressure value. When the difference between the first pressure sensor and the third pressure sensor is less than the set first threshold and the difference between the third pressure sensor and the second pressure sensor is less than the set second threshold, the solenoid valve is closed, the three-way valve is switched to connect the first and third interfaces, the compressor is started, and the air-conditioning system is started.

[0069] Normal operation stage: The solenoid valve is closed, the high-pressure storage tank remains in a state of being cut off from the main circulation loop, and the main circulation loop of the air-conditioning operates normally.

[0070] Shutdown phase: The solenoid valve is opened, the three-way valve is switched to the state where the first interface is connected to the second interface, and the opening of the expansion valve is adjusted to the maximum; The residual refrigerant in the air-conditioning pipeline and heat exchanger is sucked and compressed by the compressor, and then cooled in the precooler and stored in the high-pressure storage tank in a supercritical pressure state; The pressure value is read by the pressure monitoring module. When the difference between the third pressure sensor and the second pressure sensor is less than the third threshold and the value of the third pressure sensor is lower than the fourth threshold, the three-way valve switches to connect the first and third interfaces, closes the solenoid valve, and cuts off the connection between the high-pressure storage tank and the main circuit of the air-conditioning system; The compressor is turned off and the system shuts down.

[0071] Indoor heating: The ad and bc of the four-way valve are connected;

[0072] Startup phase: The compressor is turned off, and the second and third interfaces of the three-way valve are connected; The solenoid valve is opened, the opening of the expansion valve is adjusted, the fan of the outdoor heat exchanger is turned on, and the high-pressure refrigerant flows out of the high-pressure storage tank under the drive of the pressure difference, passes through the indoor heat exchanger, expansion valve and outdoor heat exchanger in sequence. The pressure value is read by the pressure monitoring module. When the difference between the first pressure sensor and the second pressure sensor is less than the set first threshold and the difference between the second pressure sensor and the third pressure sensor is less than the set second threshold, the solenoid valve is closed, the three-way valve is switched to connect the first and third interfaces, the compressor is started, and the air-conditioning system starts.

[0073] Normal operation phase: The solenoid valve is closed, the high-pressure storage tank remains disconnected from the main circulation circuit, and the main circulation circuit of the air conditioner operates normally.

[0074] Shutdown phase: The solenoid valve is opened, the three-way valve is switched to the state where the first interface is connected to the second interface, and the opening of the expansion valve is adjusted to the maximum; The residual refrigerant in the air-conditioning pipeline and heat exchanger is sucked and compressed by the compressor, and then cooled in the precooler and stored in the high-pressure storage tank in a supercritical pressure state; The pressure value is read by the pressure monitoring module. When the difference between the second pressure sensor and the third pressure sensor is less than the third threshold and the value of the second pressure sensor is lower than the fourth threshold, the three-way valve switches to connect the first and third interfaces, closes the solenoid valve, and cuts off the connection between the high-pressure storage tank and the main circuit of the air-conditioning system; The compressor is turned off and the system shuts down.

[0075] In this embodiment, R744 is selected as the refrigerant of the air-conditioning system, including the following steps:

[0076] Startup phase: Compressor 1 is turned off, and the second and third interfaces of three-way valve 2 are connected;

[0077] Maintain the pressure of the main circuit of the air-conditioning system ≤ 2 MPa, and the pressure of the high-pressure storage tank 5 ≤ 15 MPa;

[0078] Open the solenoid valve 9, adjust the opening of the expansion valve 7, and turn on the fan of the indoor heat exchanger 8 to produce a weak refrigeration effect;

[0079] Under the drive of the pressure difference, the high-pressure refrigerant flows out of the high-pressure storage tank 5 and successively passes through the outdoor heat exchanger 6, the expansion valve 7, and the indoor heat exchanger 8; the pressure of the high-pressure storage tank 5 gradually decreases. The section between the outdoor heat exchanger 6 and the expansion valve 7 is the high-pressure section of the air-conditioning system, where the pressure rises rapidly. The section between the expansion valve 7 and the indoor heat exchanger 8 is the low-pressure section of the air-conditioning system, where the pressure rises slowly.

[0080] When the pressure read by the first pressure sensor 101 is not higher than 8 MPa, the solenoid valve 9 is closed.

[0081] When the reading values of the third pressure sensor 103 and the second pressure sensor are less than 2 MPa, the three-way valve 2 switches to connect the first and third interfaces, and the compressor 1 is started, and the air conditioner operates in refrigeration mode.

[0082] Normal operation stage: The solenoid valve 9 is closed, and the high-pressure storage tank 5 remains disconnected from the main circulation loop. The main circulation loop of the air conditioner operates normally; monitor the pressure of 103. If the pressure value > 15 MPa, open the solenoid valve 9, adjust the three-way valve 2 to connect the first interface with the second and third interfaces respectively, and compress some of the excess refrigerant into the high-pressure storage tank 5; when the pressure value ≤ 15 MPa, close the solenoid valve 9, and the three-way valve 2 switches to connect the first and third interfaces.

[0083] Shutdown stage: The solenoid valve 9 is opened, the three-way valve 2 switches to the state where the first interface is connected to the second interface, and the opening degree of the expansion valve 7 is adjusted to the maximum.

[0084] The residual refrigerant in the air-conditioning pipeline and heat exchanger is sucked and compressed by the compressor, then cooled in the pre-cooler 4, and stored in the high-pressure storage tank 5 in a supercritical pressure state.

[0085] The pressure value is read by the pressure monitoring module. When the difference between the third pressure sensor 103 and the second pressure sensor 102 is less than 0.1 MPa and the value of the third pressure sensor 103 is lower than 2 MPa, the three-way valve 2 switches to connect the first and third interfaces, closes the solenoid valve 9, and cuts off the connection between the high-pressure storage tank 5 and the main loop of the air-conditioning system.

[0086] The compressor 1 is turned off, and the system shuts down.

[0087] Connecting the high-pressure storage tank with a root valve (solenoid valve) to the vehicle-mounted air-conditioning system can, during the system shutdown stage, utilize the existing refrigerant suction capacity of the compressor to suck and compress the vast majority of the refrigerant inside the air-conditioning system into the high-pressure storage tank, and isolate the connection between the air-conditioning system and the high-pressure storage tank by the solenoid valve, thereby maintaining the air-conditioning system at a relatively low pressure level, reducing the pressure difference between the air-conditioning and the environment, and reducing the probability of leakage. The high-pressure storage tank and the solenoid valve are welded, so the leakage risk of the high-pressure storage tank to the environment is extremely small. Welding can be used as a pre-process without affecting the overall assembly of the automotive air conditioner.

[0088] By setting up a pressure monitoring module, based on the pressure monitoring at different positions, the residual degree of refrigerant in the pipeline is determined. By setting reasonable thresholds, it is ensured that the refrigerant maintains a low pressure during the shutdown phase and sufficient refrigerant volume during the normal operation phase.

[0089] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A vehicle air conditioning system, characterized in that: It includes a compressor, a four-way valve, an indoor heat exchanger, an expansion valve and an outdoor heat exchanger connected by pipelines, the compressor outlet is connected to the first interface of the three-way valve through a pipeline, the third interface of the three-way valve is connected to one of the interfaces of the four-way valve through a pipeline, and the second interface of the three-way valve is connected to the solenoid valve and the high-pressure storage tank in sequence through a pipeline; During the startup phase, the refrigerant in the high-pressure storage tank passes through the solenoid valve and the second and third interfaces of the three-way valve, and then passes through the outdoor heat exchanger, the expansion valve, the indoor heat exchanger and the four-way valve in sequence to reach the compressor; During the shutdown phase, the refrigerant in the pipeline flows into the high-pressure storage tank through the first and second interfaces of the three-way valve and the solenoid valve under the power of the compressor.

2. A vehicle air conditioning system according to claim 1, characterized in that: The a interface of the four-way valve is connected to the third interface of the three-way valve through a pipeline, the b interface of the four-way valve is connected to the outdoor heat exchanger, the expansion valve, the indoor heat exchanger and the d interface of the four-way valve in sequence through pipelines, and the c interface of the four-way valve is connected to the compressor inlet through a pipeline.

3. The vehicle air conditioning system according to claim 1, characterized in that: A precooler is provided on the pipeline between the solenoid valve and the high-pressure storage tank.

4. The vehicle air conditioning system according to claim 1, characterized in that: A first pressure sensor is provided on the high-pressure storage tank for monitoring the pressure value of the high-pressure storage tank; a second pressure sensor is provided on the pipeline between the four-way valve and the indoor heat exchanger for obtaining the refrigerant pressure entering the indoor heat exchanger; a third pressure sensor is provided on the pipeline between the four-way valve and the outdoor heat exchanger for obtaining the refrigerant pressure entering the outdoor heat exchanger.

5. A method for operating a vehicle air conditioning system according to any one of claims 1 to 4, characterized in that: The vehicle air conditioning system includes two cycles: indoor cooling and indoor heating. During the indoor cooling cycle, the vehicle air conditioning system operates in the following steps: During the indoor refrigeration cycle, the a and b ports of the four-way valve are connected, and the c and d ports are connected; In the startup phase: the compressor is turned off, the second and third interfaces of the three-way valve are connected; the solenoid valve is turned on, the fan of the indoor heat exchanger is turned on, the opening of the expansion valve is adjusted, and the refrigerant flows out of the high-pressure storage tank under the pressure difference drive, and passes through the outdoor heat exchanger, the expansion valve and the indoor heat exchanger in turn; In the normal operation stage: the solenoid valve is closed, the high-pressure storage tank remains disconnected from the main circulation loop, and the main circulation loop of the air conditioner operates normally; During the shutdown stage: the solenoid valve opens, the three-way valve switches to the state where the first interface and the second interface are connected, and the expansion valve opening is adjusted to the maximum; the remaining refrigerant in the air-conditioning pipeline and the heat exchanger is cooled by the precooler under the power of the compressor and stored in the high-pressure storage tank in a supercritical pressure state.

6. A method for operating a vehicle air conditioning system according to claim 5, characterized in that: During the indoor refrigeration cycle, in the startup phase: when the difference between the pressure of the high-pressure storage tank and the refrigerant pressure of the outdoor heat exchanger is less than the first threshold, and the difference between the refrigerant pressure of the outdoor heat exchanger and the refrigerant pressure of the indoor heat exchanger is less than the second threshold, the solenoid valve is closed, the three-way valve is switched to connect the first and third interfaces, the compressor starts, and the air-conditioning system starts.

7. A method for operating a vehicle air conditioning system as claimed in claim 5, characterized in that: During the indoor refrigeration cycle, in the shutdown stage: when the difference between the refrigerant pressure of the outdoor heat exchanger and the refrigerant pressure of the indoor heat exchanger is less than the third threshold, and the refrigerant pressure value of the outdoor heat exchanger is lower than the fourth threshold, the three-way valve switches the first and third interfaces to connect, the solenoid valve is closed, the compressor is shut down, and the system shuts down.

8. The operating method of a vehicle air conditioning system according to claim 5, characterized in that: How the vehicle air conditioning system works during the indoor heating cycle. The steps include: During the indoor heating cycle, the a and d ports of the four-way valve are connected, and the b and c ports are connected; In the startup phase: the compressor is turned off, and the second and third interfaces of the three-way valve are connected; The solenoid valve opens, the fan of the indoor heat exchanger starts, the opening of the expansion valve is adjusted, and the refrigerant flows out of the high-pressure storage tank under the drive of the pressure difference, passing through the outdoor heat exchanger, the expansion valve and the indoor heat exchanger in sequence; In the normal operation stage: the solenoid valve is closed, the high-pressure storage tank remains disconnected from the main circulation loop, and the main circulation loop of the air conditioner operates normally; During the shutdown stage: the solenoid valve opens, the three-way valve switches to the state where the first interface and the second interface are connected, and the expansion valve opening is adjusted to the maximum; the remaining refrigerant in the air-conditioning pipeline and the heat exchanger is cooled by the precooler under the power of the compressor and stored in the high-pressure storage tank in a supercritical pressure state.

9. A method for operating a vehicle air conditioning system according to claim 8, characterized in that: During the indoor heating cycle, in the startup phase: when the difference between the pressure of the high-pressure storage tank and the refrigerant pressure of the indoor heat exchanger is less than the first threshold, and the difference between the refrigerant pressure of the indoor heat exchanger and the refrigerant pressure of the outdoor heat exchanger is less than the second threshold, the solenoid valve is closed, the three-way valve is switched to connect the first and third interfaces, the compressor starts, and the air-conditioning system starts.

10. The operating method of a vehicle air conditioning system according to claim 8, characterized in that: During the indoor heating cycle, in the shutdown stage: when the difference between the refrigerant pressure of the indoor heat exchanger and the refrigerant pressure of the outdoor heat exchanger is less than the third threshold, and the refrigerant pressure value of the indoor heat exchanger is lower than the fourth threshold, the three-way valve switches the first and third interfaces to connect, the solenoid valve is closed, the compressor is turned off, and the system shuts down.

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