Air-cooled heat exchanger suitable for CO2 automobile air conditioner

Abstract

The air-cooled heat exchanger comprises a collecting pipe assembly and a heat exchange pipe set, a flow channel space is formed in the collecting pipe assembly, a flow path separation structure is arranged in the collecting pipe assembly, and the flow channel space is divided into at least two flow paths which are sequentially communicated in the fluid flowing direction through the flow path separation structure; the heat exchange pipe group comprises a plurality of heat exchange pipes which are communicated with the collecting pipe assembly; and in the fluid flowing direction, the total circulation sectional areas of the heat exchange pipes communicated in different flow paths are not equal. The total circulation sectional areas of the heat exchange tubes communicated with different flow paths are unequal, so that the flow capacity of the flow paths can be adaptive to the dynamic change trend of physical property parameters of a refrigerant in the cooling process, the refrigerant can maintain ideal flowing speed and turbulence in each flow path section, the state of a fluid boundary layer is optimized, and the heat exchange efficiency is improved. Therefore, the heat exchange performance and the energy efficiency performance of the whole heat exchanger are improved.

Description

Technical Field

[0001] This application relates to the field of automotive air conditioning components, and in particular to an air-cooled heat exchanger suitable for CO2 automotive air conditioning. Background Technology

[0002] With increasingly stringent environmental regulations, traditional automotive air conditioning refrigerant R134a is gradually being phased out due to its extremely high global warming potential (GWP). Carbon dioxide (CO2, R744), as a natural refrigerant, has become a key replacement for next-generation automotive air conditioning refrigerants due to its advantages such as zero ozone depletion potential (ODP), extremely low global warming potential (GWP), non-toxicity, and non-flammability.

[0003] However, CO2 refrigeration systems operate on a transcritical cycle principle, with operating pressures far exceeding those of traditional R134a refrigerant systems. In gas coolers, the pressure of the CO2 fluid typically exceeds 10 MPa, and the exhaust temperature is high (reaching over 100°C). Existing conventional automotive air conditioning condensers cannot withstand the high pressure of CO2 systems, making them highly susceptible to pipe rupture and leakage. Furthermore, the drastic changes in the physical properties of CO2 in its supercritical state place higher demands on the flow path arrangement and heat exchange efficiency of the heat exchanger. Summary of the Invention

[0004] This application provides an air-cooled heat exchanger suitable for CO2 automotive air conditioning, which can solve the problem that existing automotive air conditioning heat exchangers in the related technology cannot simultaneously meet the high-pressure safe operation requirements of CO2 systems and the high-efficiency heat exchange requirements of transcritical cycles.

[0005] This application provides an air-cooled heat exchanger suitable for CO2 automotive air conditioning, comprising: A manifold assembly has a flow channel space inside, and the manifold assembly has a flow path separation structure that divides the flow channel space into at least two processes that are sequentially connected along the fluid flow direction. A heat exchange tube assembly comprising multiple heat exchange tubes connected to the manifold assembly; Along the fluid flow direction, the total flow cross-sectional area of ​​the heat exchange tubes connected to different processes is not equal.

[0006] In one embodiment, the manifold assembly includes: a first manifold and a second manifold, wherein the second manifold and the first manifold are arranged in parallel and spaced apart. In this configuration, the two ends of each heat exchange tube in the heat exchange tube group are respectively connected to the first manifold and the second manifold.

[0007] In one embodiment, both the first manifold and the second manifold are provided with a flow path separation structure. The flow path separation structure at the first manifold divides the inner cavity of the first manifold into multiple flow chambers. The flow path separation structure at the second manifold divides the inner cavity of the second manifold into multiple flow chambers.

[0008] In one embodiment, along the fluid flow direction, the number of heat exchange tubes connected to the upstream process chamber is greater than the number of heat exchange tubes connected to the downstream process chamber. The total flow cross-sectional area of ​​the heat exchange tubes connected to the upstream process chamber is greater than the total flow cross-sectional area of ​​the heat exchange tubes connected to the downstream process chamber.

[0009] In one embodiment, the heat exchange tube is a flat tube, and the cross-sectional shape of the fluid channel inside the flat tube is non-circular; The fluid channel is provided with an axially extending turbulence structure, which is configured to change the flow path of the fluid to increase turbulence.

[0010] In one embodiment, the turbulence structure includes an internal connecting wall and inner wall ribs.

[0011] In one embodiment, the heat exchanger further includes: A fin assembly comprising multiple layers of fins, wherein some of the fins are disposed between adjacent heat exchange tubes, and the uppermost fin is disposed above the uppermost heat exchange tube. Side plate; the side plate covers the uppermost fin, and both ends of the side plate are fixedly connected to the manifold assembly.

[0012] In one embodiment, an annular detection groove is provided at the connection point where the heat exchange tube is inserted into the manifold assembly, and the annular detection groove is arranged around the circumference of the heat exchange tube. The manifold assembly is provided with a channel, one end of which is connected to the annular detection groove, and the other end extends to the outside of the heat exchanger to form a leak detection port.

[0013] In one embodiment, the manifold assembly is further provided with an inlet pressure plate and an outlet pressure plate, the inlet pressure plate and the outlet pressure plate being respectively connected to the flow channel space to form the refrigerant inlet and the refrigerant outlet.

[0014] In one embodiment, a support is provided on the manifold assembly; The bracket is provided with a shock-absorbing structure, which includes an elastic bushing disposed in the mounting hole of the bracket.

[0015] The beneficial effects of the technical solutions provided in this application include: This application provides an air-cooled heat exchanger suitable for CO2 automotive air conditioning. A flow path separation structure within the manifold assembly divides the flow space into at least two sequentially connected processes along the fluid flow direction. The total flow cross-sectional area of ​​the heat exchange tubes connected to different processes along the fluid flow direction is unequal. Because the density and specific volume of carbon dioxide refrigerant exhibit significant nonlinear characteristics with temperature and pressure changes during transcritical gas cooling, the volumetric flow rate of the fluid changes drastically during the cooling process. If the flow cross-sectional area remains constant, the fluid velocity in some process sections will be too low, weakening the heat exchange capacity, or the velocity in other process sections will be too high, increasing unnecessary flow resistance. This application addresses this by making the total flow cross-sectional area of ​​the heat exchange tubes connected to different processes unequal, allowing the flow capacity of the flow path to adapt to the dynamic changes in the refrigerant's physical properties during the cooling process. This enables the refrigerant to maintain a relatively ideal flow velocity and turbulence in each process section, thereby optimizing the fluid boundary layer state, enhancing the convective heat transfer coefficient, and ultimately improving the overall heat exchange performance and energy efficiency of the heat exchanger. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Fig. 1 This is a schematic diagram of the structure provided for an embodiment of this application; Fig. 2 A front view provided for an embodiment of this application; Fig. 3 Top view provided for an embodiment of this application; Fig. 4 A side view provided for an embodiment of this application.

[0018] In the diagram: 1. Side plate; 2. Fin; 3. Flat tube; 4. First support; 5. First manifold; 6. Second support; 7. Third support; 8. Outlet pressure plate; 9. Partition plate; 10. Second manifold; 11. Cap; 12. Inlet pressure plate. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] This application provides an air-cooled heat exchanger suitable for CO2 automotive air conditioning, which can solve the problem that existing automotive air conditioning heat exchangers in the related technology cannot simultaneously meet the high-pressure safe operation requirements of CO2 systems and the high-efficiency heat exchange requirements of transcritical cycles.

[0021] See Figs. 1 to 4 This application provides an air-cooled heat exchanger suitable for CO2 automotive air conditioning, comprising: a manifold assembly and a heat exchange tube group. The manifold assembly has a flow channel space inside and a flow path separation structure inside, dividing the flow channel space into at least two processes that are sequentially connected along the fluid flow direction. The heat exchange tube group includes multiple heat exchange tubes that are connected to the manifold assembly. The total flow cross-sectional area of ​​the heat exchange tubes connected to different processes is not equal along the fluid flow direction.

[0022] This application divides the flow channel space into at least two sequentially connected processes along the fluid flow direction through a flow path separation structure within the manifold assembly, and configures the total flow cross-sectional areas of the heat exchange tubes connected to different processes along the fluid flow direction to be unequal. Because the density and specific volume of carbon dioxide refrigerant exhibit significant nonlinear characteristics with temperature and pressure changes during the transcritical gas cooling process, the volumetric flow rate of the fluid changes drastically during the cooling process. If the flow cross-sectional area remains constant, the fluid velocity in some process sections will be too low, weakening the heat exchange capacity, or the velocity in other process sections will be too high, increasing unnecessary flow resistance. This application, by making the total flow cross-sectional areas of the heat exchange tubes connected to different processes unequal, allows the flow capacity of the flow channel to adapt to the dynamic changes in the refrigerant's physical properties during the cooling process, enabling the refrigerant to maintain a relatively ideal flow velocity and turbulence in each process section, thereby optimizing the fluid boundary layer state, enhancing the convective heat transfer coefficient, and ultimately improving the overall heat exchange performance and energy efficiency of the heat exchanger.

[0023] Specifically, in this application, the manifold assembly includes a first manifold 5 and a second manifold 10, with the second manifold 10 and the first manifold 5 arranged in parallel and spaced apart. To accommodate the high operating pressure of CO2 automotive air conditioning systems, the manifolds can be made of high-strength extruded aluminum alloy profiles. This parallel arrangement ensures the stability of the overall structure, provides a positioning reference for the arrangement of the heat exchange tubes, and enables the manifolds to withstand the stress generated by the high-pressure fluid without significant deformation.

[0024] In this heat exchanger tube assembly, each heat exchanger tube is connected at both ends to the first manifold 5 and the second manifold 10, forming a continuous fluid channel. The ends of the heat exchanger tubes are inserted into pre-set holes on the manifolds and sealed and fixed using a high-temperature brazing process. This connection method achieves a metallurgical bond, preventing refrigerant leakage from the pipe joints under high-pressure conditions. Simultaneously, the manifolds have an internal flow path separation structure to guide the refrigerant through multiple reciprocating flows, thus matching the changes in refrigerant properties.

[0025] Furthermore, both the first manifold 5 and the second manifold 10 are equipped with flow path separation structures to guide and switch the refrigerant flow direction. The flow path separation structure is a partition 9. To enhance the positioning accuracy and resistance to high-pressure deformation of the connection between the partition 9 and the manifold, an annular groove is pre-set on the inner wall of the manifold, and the edge of the partition 9 has a flange that mates with the groove. After the flange is embedded in the groove, double-sided fillet welding is performed. The groove's limiting effect on the flange prevents the partition 9 from shifting under high-pressure impact, and the double-sided welding eliminates potential incomplete penetration defects that may exist in single-sided welding, ensuring the sealing reliability of the connection under high-pressure conditions in the CO2 system.

[0026] The flow path separation structure at the first manifold 5 divides the inner cavity of the first manifold 5 into multiple process chambers; the flow path separation structure at the second manifold 10 divides the inner cavity of the second manifold 10 into multiple process chambers.

[0027] To facilitate process switching, such as transitioning from one process to the next, specific communication structures exist at the flow path separation structure, i.e., partition 9. These communication structures are typically pre-reserved flow gaps between the end of partition 9 and the inner wall of the manifold, or communication windows opened on partition 9. After filling the current process chamber, the fluid flows around or through these pre-defined channels to adjacent chambers, thereby achieving physical connectivity between processes. This ensures that the refrigerant can flow sequentially through each heat exchange area along a predetermined path, preventing flow path blockage or interruption.

[0028] The baffle 9 inside the manifold, i.e., the flow path separation structure, mainly serves two functions. First, it acts as a separator, preventing refrigerants from different processes from directly mixing in the axial direction of the manifold. For example, it prevents the high-temperature inlet fluid from directly short-circuiting to the low-temperature outlet. This separator ensures axial sealing and guarantees the effectiveness of the temperature gradient. Second, it acts as a guide, forcing the fluid to change direction and enter the next set of heat exchange tubes. This guiding function utilizes the blocking characteristics of the baffle 9 to change the flow vector, causing the refrigerant to change from axial flow to transverse flow through the heat exchange tubes and then back to the manifold. Combined with the variation in the number of flat tubes 3 for different processes, this maintains the flow velocity stability of the refrigerant during the property change process and optimizes heat exchange efficiency.

[0029] In addition, a cap 11 is provided at the end of the first manifold 5 and / or the second manifold 10. The outline of the cap 11 matches the end cross-section of the first manifold 5, and the material is an aluminum alloy compatible with the manifold. The cap 11 covers the axial end of the manifold and is sealed to the end wall of the manifold through a continuous brazing process to form a closed end structure, ensuring the axial sealing of the flow channel space.

[0030] This feature is used to seal the axial end of the manifold assembly, preventing refrigerant leakage from the manifold end. Simultaneously, the cap 11 acts as an end reinforcement, increasing the structural rigidity of the manifold end, resisting axial stress generated by internal high pressure, preventing end weld cracking, and ensuring the sealing integrity of the heat exchanger under high-pressure conditions.

[0031] In this embodiment, along the fluid flow direction, the number of heat exchange tubes connected to the upstream process chamber is greater than the number connected to the downstream process chamber. Since the heat exchange tubes have uniform cross-sectional dimensions, the distribution of their number directly determines the flow capacity of the channel. Therefore, the total flow cross-sectional area of ​​the heat exchange tubes connected to the upstream process chamber is greater than that of the heat exchange tubes connected to the downstream process chamber. This simultaneous decrease in both number and area constitutes the basic physical form of the multi-flow variable cross-section flow path structure, ensuring that the channel geometry can flexibly adapt to the flow requirements of the fluid under different thermodynamic states, providing a structural basis for subsequent process switching.

[0032] In the design of a multi-stage heat exchange loop, the number of flat tubes 3 in the first stage (inlet) is greater than the number in the final stage (outlet) to accommodate the gradual decrease in specific volume during CO2 gas cooling. During the heat release process, the density of supercritical CO2 fluid increases significantly while its specific volume decreases accordingly. If the flow cross-sectional area remains constant, the fluid velocity will decrease dramatically as the specific volume decreases, leading to a lower Reynolds number. By progressively reducing the flow cross-sectional area, the fluid velocity can be maintained, ensuring heat exchange efficiency and preventing boundary layer thickening due to excessively low velocity, which would deteriorate the heat exchange effect. Simultaneously, the flow resistance between stages is balanced, preventing excessive pressure loss due to locally high velocity.

[0033] High-temperature, high-pressure supercritical CO2 gas enters the first flow path (uppermost chamber) through the inlet pressure plate 12, flows through a large number of flat tubes 3 to the second manifold 10, and then flows through the lower region in stages. In the design, a larger number of flat tubes 3 are used in the upper high-temperature zone to provide a matching flow cross-sectional area to accommodate the large specific volume of the high-temperature gas. As the CO2 temperature decreases and its density increases, the number of flat tubes 3 is reduced in the lower low-temperature zone to decrease the flow cross-sectional area. This configuration avoids excessively low flow rates that could lead to heat exchange deterioration, ensures that the refrigerant maintains an effective turbulent state throughout the cooling process, optimizes temperature glide matching, improves the overall system efficiency, and simultaneously meets the special requirements of the CO2 transcritical cycle for the heat exchanger flow path arrangement.

[0034] The flow channel design employs a two-pass structure, where the refrigerant undergoes two round trips within the heat exchange tube assembly to complete the heat exchange process, ensuring sufficient heat exchange between the fluid and the air side. The manifold assembly is also equipped with an inlet pressure plate 12 and an outlet pressure plate 8, which are respectively connected to the flow channel space to form the refrigerant inlet and outlet. The pressure plates have through holes corresponding to the manifold tube openings, which are brazed to create a sealed connection with the outer wall of the manifold, forming independent fluid inlet and outlet channels. This prevents refrigerant leakage or bypass at the end of the manifold, ensuring that the fluid enters the flow channel space along a predetermined path. Simultaneously, the pressure plate structure enhances the local strength at the end of the manifold.

[0035] In this application, in conjunction with the two-flow structure, the inlet pressure plate 12 and the outlet pressure plate 8 are respectively disposed on the first manifold 5. The inlet pressure plate 12 is located in the upper region of the first manifold 5, and the outlet pressure plate 8 is located in the lower region of the first manifold 5. The first manifold 5 is internally equipped with a partition plate 9, which isolates the inner cavity into an independent upper inlet chamber and a lower outlet chamber, preventing direct short-circuiting of the inlet and outlet fluids within the manifold. The refrigerant enters from the upper inlet chamber, flows through the heat exchange tube to the second manifold 10, then turns and returns to the lower outlet chamber of the first manifold 5 for discharge. This same-side inlet and outlet layout not only shortens the external pipeline connection distance, facilitating a compact vehicle layout, but also utilizes the height difference to reduce fluid stagnation, optimizing the flow stability of CO2 refrigerant under high-pressure conditions and the convenience of system maintenance, thus adapting to the space constraints of automotive air conditioning systems.

[0036] Based on the above embodiments, in this embodiment, the heat exchange tube is a flat tube 3. The manifold assembly is made of high-strength extruded aluminum alloy profile. Considering that the operating pressure of the CO2 system is much higher than that of traditional refrigerants, the wall thickness of the manifold is greater than that of the manifold in a traditional R134a condenser to provide sufficient structural strength to resist radial expansion stress and avoid fatigue failure caused by pressure fluctuations. The connection between the manifold and the flat tube 3 adopts a high-pressure flared connection structure and is sealed and reinforced by brazing. Specifically, after the end of the flat tube 3 is inserted into the manifold hole, it is flared to increase the contact area and form a mechanical interference fit. Combined with the metallurgical brazing seam, the sealing performance is doubly guaranteed. The flat tube 3 is made of high-strength aluminum alloy material and its wall thickness is set at 0.5-0.8mm. This thickness range takes into account both pressure resistance and thermal conductivity. Too thick a thickness will affect heat exchange, while too thin a thickness will not meet the strength requirements. The connection between the manifold and flat tube 3 employs a nitrogen-protected continuous brazing process to prevent the formation of an oxide film at high temperatures that could affect the wetting of the brazing filler metal. High-strength composite brazing filler metal is used to ensure the joint remains leak-free under high-pressure impact. Bench testing showed that the heat exchanger exhibited no deformation under a working pressure of 12.5 MPa, verifying the reliability of the structural design. Furthermore, at an ambient temperature of 40°C, the cooling capacity was increased by approximately 15% compared to the traditional structure, demonstrating the performance gains resulting from structural optimization.

[0037] The fluid channel within the flat tube 3 has a non-circular cross-sectional shape. An axially extending turbulence structure is provided within the fluid channel, configured to alter the fluid's flow path and increase turbulence. Further, the turbulence structure includes an internal connecting wall and internal wall ribs. In this embodiment, this is specifically manifested as multiple axially penetrating holes within the flat tube 3, with the holes having a figure-eight cross-sectional shape. The connecting wall in the middle of this figure-eight structure not only serves as a turbulence element but also acts as an internal support rib, increasing the moment of inertia of the cross-section, preventing the flat tube 3 from collapsing and deforming under high pressure, and decomposing the large cross-section into two smaller cross-sections to reduce the pressure load on a single cavity. The wall thickness of the flat tube 3 is designed to be thickened according to pressure resistance requirements, working in conjunction with the irregular cross-section to jointly withstand the internal pressure. The figure-eight cross-sectional shape of the pipe holes causes flow diversion and convergence when the fluid flows through the middle connecting wall, enhancing fluid turbulence, disrupting the thermal boundary layer, and increasing the convective heat transfer coefficient of CO2 fluid in the supercritical state. This design takes advantage of the dramatic changes in the physical properties of CO2 in the quasi-critical region. By inducing turbulence through structure, it effectively enhances the heat transfer efficiency during the gas cooling process, while ensuring the long-term stability of the structure under high pressure, thus meeting the dual requirements of compactness and safety for automotive air conditioning systems.

[0038] Furthermore, an annular detection groove is provided at the connection point where the heat exchange tube is inserted into the manifold assembly. This detection groove is opened on the outer wall of the manifold orifice, located around the weld joint between the flared end of the heat exchange tube and the manifold. The annular detection groove is arranged around the circumference of the heat exchange tube, forming a closed annular collection chamber, ensuring that refrigerant can be preferentially captured regardless of where a micro-leak occurs around the weld circumference, achieving all-round leak monitoring.

[0039] The manifold assembly features a microchannel, one end of which connects to an annular detection groove, while the other end extends to the outside of the heat exchanger, forming a leak detection port. The microchannel aperture is designed to balance flow capacity with the structural strength of the manifold, and the leak detection port is equipped with a sensor interface. When the internal operating pressure is higher than the external pressure, the leaking fluid preferentially enters the detection groove under the pressure difference and is then discharged through the microchannel. An external sensor provides early warning, preventing the safety hazards caused by direct high-pressure CO2 injection.

[0040] Based on the above embodiments, in this embodiment, the heat exchanger further includes fin group 2 and side plate 1, which together constitute an air-side heat exchange and structural support unit. Fin group 2 includes multiple layers of fins 2, some of which are disposed between adjacent heat exchange tubes, utilizing the contact area between the fin crests and the surface of the heat exchange tubes for heat transfer; the uppermost fin 2 is disposed above the uppermost heat exchange tube, filling the airflow channel gap above the top tube bank. Side plate 1 covers the uppermost fin 2, and both ends of side plate 1 are fixedly connected to the manifold assembly, for example, by brazing or mechanical snap-fitting to the top of the first manifold 5 and the second manifold 10. This top-closed structure not only guides all air to flow through the gaps between fins 2 to prevent bypass, but also acts as a reinforcing rib to constrain the overall displacement of the heat exchange tube assembly, resisting the tube bank expansion tendency caused by CO2 high pressure and the vibration load during vehicle operation, thus enhancing the overall rigidity of the core.

[0041] Fin 2 is a high-strength corrugated fin or a windowed fin, typically made of aluminum alloy. Its corrugation height and fin spacing are optimized to balance air resistance and heat exchange area. The surface of fin 2 is coated with a hydrophilic coating. This coating reduces the surface tension of water, causing moisture in the air to form a uniform water film on the fin surface instead of individual water droplets. This prevents condensation from clogging the air duct under certain operating conditions and improves air-side heat exchange efficiency. Especially when the system is operating as a heat pump or in environments with high humidity, the hydrophilic coating accelerates the discharge of condensate, avoids water bridging, and prevents increased airflow resistance. This ensures that the heat exchanger maintains stable air-side heat exchange performance during long-term operation, adapting to the complex and variable working environment of automotive air conditioning systems.

[0042] Based on the above embodiments, in this implementation, a bracket is provided on the manifold assembly to achieve mechanical connection and fixation between the heat exchanger and the vehicle body. In this embodiment, the bracket includes a first bracket 4 and a second bracket 6 disposed on the second manifold 10, and a third bracket 7 disposed on the first manifold 5. The three brackets are distributed along the length of the heat exchanger, forming a stable multi-point support structure. The bracket and the manifold assembly are connected by integrated brazing or high-strength welding process to ensure that the connection root has sufficient shear strength, avoiding loosening or breakage under vehicle driving vibration or refrigerant high-pressure pulsation, balancing the overall stress distribution of the heat exchanger, and preventing the manifold from twisting and deforming due to single-point support.

[0043] The bracket features a vibration damping structure, including an elastic bushing installed within the mounting holes of the bracket. The elastic bushing is made of rubber material resistant to high and low temperatures and oil corrosion, and fits tightly into the inner wall of the mounting holes. Mounting bolts pass through the elastic bushing to fix the bracket to the vehicle body. The deformation capability of the elastic bushing isolates mechanical vibrations transmitted from the vehicle body and high-frequency pulsations generated by the compressor operation. This flexible connection method blocks the direct transmission path of vibration energy, reduces the alternating stress amplitude at the manifold connection, prevents refrigerant leakage due to long-term vibration fatigue, ensures the structural reliability of the CO2 high-pressure system in actual operating environments, and adapts to the complex and variable vibration conditions of automotive air conditioning systems.

[0044] In summary, this application has the following advantages: excellent high pressure resistance: by increasing the wall thickness of the manifold and flat tube, the overall pressure resistance of the heat exchanger reaches more than 14MPa, which fully meets the high pressure safety requirements of CO2 transcritical cycle.

[0045] High heat exchange efficiency: The flat tube with 3 holes has an "8" shaped cross-section and a variable flow design. Combined with fins 2 with a high heat transfer coefficient, it effectively utilizes the huge specific heat capacity change characteristics of CO2 in the quasi-critical region, thus enhancing the heat exchange effect.

[0046] Compact and lightweight structure: Compared with shell-and-tube gas coolers with the same cooling capacity, the present invention has a significantly reduced volume, which meets the requirements of lightweight and compact layout of automotive parts.

[0047] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a 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 between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0048] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0049] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A gas-cooled heat exchanger suitable for CO2 automotive air conditioning, characterized in that, It includes: A manifold assembly has a flow channel space inside, and the manifold assembly has a flow path separation structure that divides the flow channel space into at least two processes that are sequentially connected along the fluid flow direction. A heat exchange tube assembly comprising multiple heat exchange tubes connected to the manifold assembly; Along the fluid flow direction, the total flow cross-sectional area of ​​the heat exchange tubes connected to different processes is not equal.

2. The air-cooled heat exchanger for CO2 automotive air conditioning as described in claim 1, characterized in that, The manifold assembly includes: First manifold (5); The second manifold (10) and the first manifold (5) are arranged in parallel at intervals; The two ends of each heat exchange tube in the heat exchange tube group are respectively connected to the first manifold (5) and the second manifold (10).

3. The air-cooled heat exchanger for CO2 automotive air conditioning as described in claim 2, characterized in that: The first manifold (5) and the second manifold (10) are both equipped with flow path separation structures. The flow path separation structure at the first manifold (5) divides the inner cavity of the first manifold (5) into multiple flow chambers. The flow path separation structure at the second manifold (10) divides the inner cavity of the second manifold (10) into multiple flow chambers.

4. The air-cooled heat exchanger for CO2 automotive air conditioning as described in claim 3, characterized in that: Along the fluid flow direction, the number of heat exchange tubes connected to the upstream process chamber is greater than the number of heat exchange tubes connected to the downstream process chamber. The total flow cross-sectional area of ​​the heat exchange tubes connected to the upstream process chamber is greater than the total flow cross-sectional area of ​​the heat exchange tubes connected to the downstream process chamber.

5. The air-cooled heat exchanger for CO2 automotive air conditioning as described in claim 1, characterized in that: The heat exchange tube is a flat tube (3), and the cross-sectional shape of the fluid channel inside the flat tube (3) is non-circular; The fluid channel is provided with an axially extending turbulence structure, which is configured to change the flow path of the fluid to increase turbulence.

6. The air-cooled heat exchanger for CO2 automotive air conditioning as described in claim 5, characterized in that: The turbulence structure includes an internal connecting wall and inner wall ribs.

7. The air-cooled heat exchanger for CO2 automotive air conditioning as described in claim 1, characterized in that: The heat exchanger also includes: A fin (2) group, wherein the fin (2) group includes multiple layers of fins (2), wherein some of the fins (2) are disposed between adjacent heat exchange tubes, and the uppermost fin (2) is disposed above the uppermost heat exchange tube; Side plate (1); the side plate (1) covers the uppermost fin (2), and both ends of the side plate (1) are fixedly connected to the manifold assembly.

8. The air-cooled heat exchanger for CO2 automotive air conditioning as described in claim 1, characterized in that: An annular detection groove is provided at the connection point where the heat exchange tube is inserted into the manifold assembly, and the annular detection groove is arranged around the circumference of the heat exchange tube. The manifold assembly is provided with a channel, one end of which is connected to the annular detection groove, and the other end extends to the outside of the heat exchanger to form a leak detection port.

9. The air-cooled heat exchanger for CO2 automotive air conditioning as described in claim 1, characterized in that: The manifold assembly is also provided with an inlet pressure plate (12) and an outlet pressure plate (8), which are respectively connected to the flow channel space to form a refrigerant inlet and a refrigerant outlet.

10. The air-cooled heat exchanger for CO2 automotive air conditioning as described in claim 1, characterized in that: The manifold assembly is provided with a bracket; The bracket is provided with a shock-absorbing structure, which includes an elastic bushing disposed in the mounting hole of the bracket.

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