Cooler, exhaust gas recirculation system and engine

Abstract

The utility model provides a kind of cooler, waste gas recirculation system and engine, cooler includes cooler main body, and cooler further includes precooling structure, and precooling structure is connected with cooler main body;Precooling structure includes precooling bellows and precooling shell, precooling shell is set in precooling bellows outside and the first cooling cavity for accommodating first cooling medium is formed between two, to make first cooling medium and the gas that is passed into precooling bellows inside heat exchange;Precooling bellows is connected with cooler main body, to make the gas after heat exchange in precooling structure into cooler main body and heat exchange.The cooler of the utility model solves the problem of low reliability of cooler in the prior art.

Description

Technical Field

[0001] This utility model relates to the field of engine technology, and more specifically, to a cooler, an exhaust gas recirculation system, and an engine. Background Technology

[0002] EGR (Exhaust Gas Recirculation) refers to a method where a portion of the exhaust gas is drawn from the exhaust pipe and then flows back into the engine cylinders through the intake manifold. Because the exhaust gas contains a large amount of inert gases, it dilutes the fresh air-fuel mixture, slowing down the combustion speed. Simultaneously, the exhaust gas recirculation increases the heat capacity of the working fluid during combustion, i.e., increases its specific heat. Both of these factors lower the maximum combustion temperature and effectively suppress NO₂. X The generation of nitrogen oxides in exhaust gas is reduced, as is the tendency for detonation.

[0003] Currently, EGR coolers are used to cool EGR gas. EGR coolers use cooling pipes to reduce the temperature of EGR gas. The cooling pipes are metal pipes used for heat exchange between EGR exhaust gas and coolant.

[0004] However, EGR coolers, especially those used in natural gas engines, have very high EGR intake air temperatures and require high heat exchange performance. They typically use cooling pipes with high heat transfer coefficients. The main board and cooling pipes are subjected to very high thermal stress, which often leads to cracks and leaks at the connection between the EGR cooler intake main board and the cooling pipes, resulting in low cooler reliability. Utility Model Content

[0005] The main objective of this invention is to provide a cooler, an exhaust gas recirculation system, and an engine to solve the problem of low reliability of coolers in the prior art.

[0006] To achieve the above objectives, according to a first aspect of the present invention, a cooler is provided, comprising a cooler body and a precooling structure connected to the cooler body. The precooling structure includes a precooling bellows and a precooling shell, the precooling shell being sleeved outside the precooling bellows and forming a first cooling chamber between them for containing a first cooling medium, so that the first cooling medium exchanges heat with the gas introduced into the precooling bellows. The precooling bellows is connected to the cooler body so that the gas after heat exchange through the precooling structure enters the cooler body for heat exchange.

[0007] Furthermore, the cooler also includes an air inlet chamber, one end of which is connected to the precooling structure and communicates with the precooling bellows, and the other end of which is connected to the cooler body, so that the gas in the precooling bellows enters the cooler body through the air inlet chamber.

[0008] Furthermore, the intake chamber has a bent pipe structure so that the precooling structure and the main body of the cooler are inclined to each other, and the precooling corrugated pipe is inclined to the main cooling pipe of the main body of the cooler.

[0009] Furthermore, the precooling structure and the main body of the cooler are arranged perpendicularly, and the precooling corrugated pipe is arranged perpendicularly to the main cooling pipe.

[0010] Furthermore, the precooling structure includes an inlet flange for connecting to external components, the inlet flange being disposed at the inlet end of the precooling bellows, and the precooling housing being connected to the inlet flange; and / or, the precooling structure further includes: a first inflow portion, connected to the precooling housing and communicating with the first cooling chamber, so that the first cooling medium enters the first cooling chamber from the first inflow portion; and a first outflow portion, connected to the precooling housing and communicating with the first cooling chamber, so that the first cooling medium that has completed heat exchange in the first cooling chamber flows out from the first outflow portion.

[0011] Furthermore, the cooler is used to connect to one flow channel, and the precooling structure includes a precooling bellows connected to the flow channel; or, the cooler is used to connect to two flow channels, and the precooling structure includes two precooling bellows, which are arranged one-to-one with the two flow channels, and each precooling bellows is connected to the corresponding flow channel.

[0012] Furthermore, the main body of the cooler includes multiple main cooling pipes, an intake main plate, an exhaust main plate, and a main cooling shell. The intake main plate and the exhaust main plate are both connected to the main cooling shell and together with the main cooling shell form a second cooling chamber. Multiple main cooling pipes are spaced apart in the second cooling chamber. One end of each main cooling pipe is connected to the intake main plate, and the other end of each main cooling pipe is connected to the exhaust main plate. Among them, multiple main cooling pipes are plate-fin type cooling pipes, and fins are provided inside the main cooling pipes; or, the main cooling pipes are dotted pipes.

[0013] Furthermore, the cooler body also includes a second inlet and a second outlet. The second inlet is connected to the main cold shell and communicates with the second cooling chamber, so that the second cooling medium enters the second cooling chamber from the second inlet. The second outlet is connected to the main cold shell and communicates with the second cooling chamber, so that the second cooling medium that has completed heat exchange in the second cooling chamber flows out from the second inlet. And / or, the cooler also includes an exhaust chamber, which is connected to the main cold shell and communicates with multiple main cold cooling pipes.

[0014] According to a second aspect of the present invention, an exhaust gas recirculation system is provided, including the cooler described above.

[0015] According to a third aspect of the present invention, an engine is provided, including the exhaust gas recirculation system described above.

[0016] The present invention provides a cooler comprising a cooler body and a pre-cooling structure. EGR exhaust gas flows through the pre-cooling corrugated pipe, which contacts a first cooling medium, transferring heat from the exhaust gas to the first cooling medium and reducing the EGR exhaust gas temperature. The corrugations on the pre-cooling corrugated pipe are expandable and deformable upon thermal expansion, preventing thermal stress and significantly improving thermal fatigue reliability. The corrugations on the pre-cooling corrugated pipe can increase the heat transfer coefficient between the pipe wall and the exhaust gas and increase the heat transfer area through turbulence, thereby improving heat transfer performance and minimizing the exhaust gas temperature. However, its heat transfer performance is still relatively poor compared to plate-fin cooling pipes and pitted pipes, absorbing relatively less heat from the gas side. Therefore, the temperature and thermal stress are lower, significantly improving thermal fatigue reliability at this location. When the EGR exhaust gas reaches the cooler body, its temperature has already been reduced by the pre-cooling corrugated pipe, significantly lowering the cooler body temperature and thermal stress, and significantly improving thermal fatigue reliability. Therefore, this cooler solves the problem of low cooler reliability and also ensures the heat transfer efficiency of the cooler. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0018] Figure 1 A schematic diagram of an embodiment of the cooler according to the present invention is shown;

[0019] Figure 2 It shows Figure 3 A sectional view of the cooler at section AA in the middle;

[0020] Figure 3 It shows Figure 2 A sectional view of the cooler at section BB in the middle;

[0021] Figure 4 It shows Figure 3 A cross-sectional view of the cooler at section C of the cooling unit;

[0022] Figure 5 It shows Figure 3 A cross-sectional view of the cooler at section DD;

[0023] Figure 6 A schematic diagram of the precooling bellows of the cooler according to the present invention is shown;

[0024] Figure 7 A schematic diagram is shown of a main cooling pipe of the cooler according to the present invention, which is a plate-fin type cooling pipe;

[0025] Figure 8 A schematic diagram of a main cooling pipe of a cooler according to the present invention, which is a pitted pipe, is shown.

[0026] Figure 9 A top view of an embodiment of the cooler according to the present invention is shown;

[0027] Figure 10 A side view of an embodiment of the cooler according to the present invention is shown;

[0028] Figure 11 A front view of an embodiment of the cooler according to the present invention is shown.

[0029] The above figures include the following reference numerals:

[0030] 100. Cooler body; 200. Pre-cooling structure;

[0031] 1. Inlet flange; 2. Pre-cooling shell; 3. First inlet section; 4. First outlet section; 5. Pre-cooling bellows; 6. Inlet chamber; 7. Inlet main plate; 8. Main cooling pipe; 9. Main cooling shell; 10. Second inlet section; 11. Second outlet section; 12. Outlet main plate; 13. Outlet chamber; 14. Sealing gasket; 15. Fastening bolts. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0034] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, 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.

[0035] This utility model provides a cooler; please refer to [reference needed]. Figures 1 to 11The system includes a cooler body 100 and a precooling structure 200 connected to the cooler body 100. The precooling structure 200 includes a precooling bellows 5 and a precooling shell 2. The precooling shell 2 is fitted over the precooling bellows 5 and forms a first cooling chamber between them to accommodate a first cooling medium, so that the first cooling medium can exchange heat with the gas introduced into the precooling bellows 5. The precooling bellows 5 is connected to the cooler body 100 so that the gas after heat exchange in the precooling structure 200 can enter the cooler body 100 for heat exchange.

[0036] The cooler of this invention includes a cooler body 100 and a pre-cooling structure 200. EGR exhaust gas flows through the pre-cooling corrugated pipe 5, which is in contact with a first cooling medium. The pre-cooling corrugated pipe 5 transfers heat from the exhaust gas to the first cooling medium, reducing the EGR exhaust gas temperature. Its corrugations are expandable and deformable upon thermal expansion, preventing thermal stress and significantly improving thermal fatigue reliability. The corrugations on the pre-cooling corrugated pipe 5 can increase the heat transfer coefficient between the pipe wall and the exhaust gas and increase the heat transfer area through turbulence, thereby improving heat transfer performance and minimizing the exhaust gas temperature. However, its heat transfer performance is still relatively poor compared to plate-fin cooling pipes and pitted pipes, absorbing relatively less heat from the gas side. Therefore, the temperature and thermal stress are lower, significantly improving thermal fatigue reliability at this location. When the EGR exhaust gas reaches the cooler body 100, its temperature has already been reduced by the pre-cooling corrugated pipe 5, significantly lowering the temperature and thermal stress of the cooler body 100 and significantly improving thermal fatigue reliability. Therefore, this cooler solves the problem of low cooler reliability and also ensures the heat transfer efficiency of the cooler.

[0037] In this embodiment, the cooler further includes an air inlet chamber 6, one end of which is connected to the precooling structure 200 and communicates with the precooling bellows 5, and the other end of which is connected to the cooler body 100, so that the gas in the precooling bellows 5 enters the cooler body 100 through the air inlet chamber 6. This arrangement realizes the connection between the cooler body 100 and the precooling structure 200 and the transmission of gas.

[0038] In this embodiment, the air inlet chamber 6 has a bent pipe structure, so that the precooling structure 200 and the cooler body 100 are inclined to each other, and the precooling corrugated pipe 5 is inclined to the main cooling pipe 8 of the cooler body 100. This arrangement can reduce the size of the cooler in the extension direction of the main cooling pipe 8, and on this basis, it can ensure that the size of the precooling corrugated pipe 5 is long enough to ensure the heat exchange effect.

[0039] In this embodiment, the precooling structure 200 and the cooler body 100 are arranged perpendicularly, and the precooling corrugated pipe 5 is arranged perpendicularly to the main cooling pipe 8. This arrangement can further reduce the size of the cooler in the extension direction of the main cooling pipe 8, and on this basis, the length of the precooling corrugated pipe 5 can be extended further to ensure the heat exchange effect.

[0040] In this embodiment, the precooling structure 200 includes an inlet flange 1 for connection with external components. The inlet flange 1 is disposed at the inlet end of the precooling bellows 5, and the precooling housing 2 is connected to the inlet flange 1. This arrangement facilitates the connection of the inlet flange 1 with external components.

[0041] In this embodiment, the precooling structure 200 further includes: a first inflow section 3, which is connected to the precooling shell 2 and communicates with the first cooling cavity, so that the first cooling medium enters the first cooling cavity from the first inflow section 3; and a first outflow section 4, which is connected to the precooling shell 2 and communicates with the first cooling cavity, so that the first cooling medium that has completed heat exchange in the first cooling cavity flows out from the first outflow section 4.

[0042] In practice, the first inflow section 3 and the first outflow section 4 can be separate parts, or the pre-cooling shell 2 can be integrated into one unit.

[0043] Specifically, the cooler is used to connect to one flow channel, and the precooling structure 200 includes a precooling corrugated pipe 5 connected to the flow channel; or, the cooler is used to connect to two flow channels, and the precooling structure 200 includes two precooling corrugated pipes 5, which are arranged one-to-one with the two flow channels, and each precooling corrugated pipe 5 is connected to its corresponding flow channel. The external component includes one or two flow channels.

[0044] In this embodiment, the cooler body 100 includes a plurality of main cooling pipes 8, an air inlet main plate 7, an air outlet main plate 12, and a main cooling shell 9. The air inlet main plate 7 and the air outlet main plate 12 are both connected to the main cooling shell 9 and together with the main cooling shell 9 form a second cooling chamber. The plurality of main cooling pipes 8 are spaced apart in the second cooling chamber. One end of each main cooling pipe 8 is connected to the air inlet main plate 7, and the other end of each main cooling pipe 8 is connected to the air outlet main plate 12.

[0045] In practice, the intake plate 7 and the exhaust plate 12 are located at the intake and exhaust ends of the cooler body 100, respectively, and are both metal plates used to connect and fix the main cooling pipes 8 together. The intake plate 7 and the exhaust plate 12 are both welded to the main cooling shell 9, or they can be assembled together with bolts or the like.

[0046] Specifically, all main cooling pipes 8 are plate-fin type cooling pipes, with fins installed inside the main cooling pipes 8; or, the main cooling pipes 8 are dotted pipes. In practical implementation, EGR exhaust gas flows through the main cooling pipes 8, and the outside contacts the second cooling medium, transferring the heat of the exhaust gas to the second cooling medium to reduce the temperature of the EGR exhaust gas. Plate-fin type cooling pipe structures or tube bundle structures such as dotted pipes can be used, which have high heat exchange efficiency and can quickly reduce the temperature of the EGR exhaust gas.

[0047] In practice, the plate-fin cooling tubes are flat tubes with internal air-side fins to increase the contact area between the metal and the EGR exhaust gas, resulting in higher heat exchange efficiency. All the main cooling tubes 8 are plate-fin cooling tubes, which have high heat exchange efficiency. Although the temperature is high, they cannot release thermal stress themselves, resulting in poor reliability. However, the temperature of the exhaust gas entering the cooler body 100 has been reduced after pre-cooling.

[0048] In practical implementation, the pitted tube, also called the uneven tube, has evenly distributed small pits (pockmarks) or small protrusions on its surface, resulting in high heat exchange efficiency and rapid reduction of EGR exhaust gas temperature. Although it cannot deform itself, cannot absorb thermal deformation, has high thermal stress, and poor reliability, the temperature of the exhaust gas entering the cooler body 100 has already been reduced after pre-cooling.

[0049] In this embodiment, the cooler body 100 further includes a second inflow portion 10 and a second outflow portion 11. The second inflow portion 10 is connected to the main cold shell 9 and communicates with the second cooling chamber so that the second cooling medium enters the second cooling chamber from the second inflow portion 10. The second outflow portion 11 is connected to the main cold shell 9 and communicates with the second cooling chamber so that the second cooling medium that has completed heat exchange in the second cooling chamber flows out from the second inflow portion 10.

[0050] In practice, the second inflow section 10 and the second outflow section 11 can be separate parts or integrated with the main cold housing 9.

[0051] In specific implementation, the flow paths between the first inflow section 3 and the first outflow section 4, and between the second inflow section 10 and the second outflow section 11, can be connected in parallel; the first outflow section 4 and the second inflow section 10 can be directly connected, and the flow paths are connected in series.

[0052] In this embodiment, the cooler also includes an exhaust chamber 13, which is connected to the main cooling housing 9 and is also connected to a plurality of main cooling pipes 8.

[0053] Specifically, both the intake chamber 6 and the exhaust chamber 13 are welded to the main cooling housing 9, or they can be assembled together using fastening bolts 15. Sealing gaskets 14 are provided between the intake chamber 6 and the main cooling housing 9, and between the exhaust chamber 13 and the main cooling housing 9, to achieve sealing between the intake chamber 6 and the main cooling housing 9, and between the exhaust chamber 13 and the main cooling housing 9.

[0054] Specifically, both the first and second cooling media are coolant; optionally, the coolant is water.

[0055] In practice, the EGR exhaust gas enters through the inlet of the inlet flange 1, flows through the pre-cooling bellows 5, is cooled down by the pre-cooling bellows 5 (reduced by about 100°C), then passes through the inlet chamber 6 to the inlet main plate 7, and then flows through the main cooling pipe 8 and the outlet main plate 12 before flowing out from the outlet chamber 13.

[0056] Furthermore, the pre-cooled corrugated pipe 5 carries EGR exhaust gas, while its exterior contacts the first cooling medium, transferring heat from the exhaust gas to the first cooling medium and reducing the EGR exhaust gas temperature. The corrugations on the pre-cooled corrugated pipe 5 are expandable and deformable upon thermal expansion, preventing thermal stress and significantly improving thermal fatigue reliability. The corrugations on the pre-cooled corrugated pipe 5 can increase the heat transfer coefficient between the pipe wall and the exhaust gas and increase the heat transfer area through turbulence, thereby improving heat transfer performance and minimizing the exhaust gas temperature. However, its heat transfer performance is still relatively poor compared to plate-fin cooling pipes and pitted pipes, absorbing relatively less heat from the gas side. Therefore, the temperature and thermal stress are lower, significantly improving thermal fatigue reliability at this location.

[0057] Furthermore, when the EGR exhaust gas temperature reaches the intake main board 7 position, the temperature has been reduced by the pre-cooling bellows 5 to around 700℃ or lower. The temperature and thermal stress at the intake main board 7 position are significantly reduced, and the thermal fatigue reliability is significantly improved.

[0058] This invention employs a pre-cooling plus main cooling structure. The pre-cooling uses a water jacket and corrugated gas pipes to initially cool the high-temperature gas. The corrugated gas pipes themselves can absorb thermal deformation through their corrugations, resulting in low thermal stress and high reliability. The corrugations can also increase the heat transfer coefficient between the pipe wall and the EGR exhaust gas through turbulence, thereby improving heat transfer performance and reducing the EGR exhaust gas temperature by about 100°C. The main cooling uses high-efficiency cooling pipes with high heat transfer performance. Because the EGR exhaust gas temperature has already been reduced by the pre-cooling, the temperature and thermal stress at the main cooling board position and the front end of the cooling pipes in the second stage are greatly reduced, significantly improving reliability.

[0059] The precooling structure 200 of this utility model is equipped with a corrugated cooling pipe with high reliability and poor heat exchange performance, which focuses on improving reliability. The main body of the cooler 100 uses plate-fin cooling pipes or pitted pipes with high heat exchange performance to ensure high heat exchange performance. Since the precooling part has greatly reduced the temperature of the exhaust gas, there is no problem with reliability. The combination of the two stages improves reliability and maintains high heat exchange performance.

[0060] This invention also provides an exhaust gas recirculation system, including the cooler described in the above embodiment.

[0061] This invention also provides an engine, including the exhaust gas recirculation system described in the above embodiments.

[0062] As can be seen from the above description, the embodiments of this utility model achieve the following technical effects:

[0063] The cooler of this invention includes a cooler body 100 and a pre-cooling structure 200. EGR exhaust gas flows through the pre-cooling corrugated pipe 5, which is in contact with a first cooling medium. The pre-cooling corrugated pipe 5 transfers heat from the exhaust gas to the first cooling medium, reducing the EGR exhaust gas temperature. Its corrugations are expandable and deformable upon thermal expansion, preventing thermal stress and significantly improving thermal fatigue reliability. The corrugations on the pre-cooling corrugated pipe 5 can increase the heat transfer coefficient between the pipe wall and the exhaust gas and increase the heat transfer area through turbulence, thereby improving heat transfer performance and minimizing the exhaust gas temperature. However, its heat transfer performance is still relatively poor compared to plate-fin cooling pipes and pitted pipes, absorbing relatively less heat from the gas side. Therefore, the temperature and thermal stress are lower, significantly improving thermal fatigue reliability at this location. When the EGR exhaust gas reaches the cooler body 100, its temperature has already been reduced by the pre-cooling corrugated pipe 5, significantly lowering the temperature and thermal stress of the cooler body 100 and significantly improving thermal fatigue reliability. Therefore, this cooler solves the problem of low cooler reliability and also ensures the heat transfer efficiency of the cooler.

[0064] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0065] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0066] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A cooler, comprising a cooler body (100), characterized in that, The cooler also includes a precooling structure (200) connected to the cooler body (100); The precooling structure (200) includes a precooling corrugated pipe (5) and a precooling shell (2). The precooling shell (2) is sleeved outside the precooling corrugated pipe (5) and a first cooling cavity is formed between the two to accommodate the first cooling medium, so that the first cooling medium exchanges heat with the gas introduced into the precooling corrugated pipe (5). The precooling corrugated pipe (5) is connected to the cooler body (100) so that the gas after heat exchange through the precooling structure (200) enters the cooler body (100) for heat exchange.

2. The cooler according to claim 1, characterized in that, The cooler also includes: An air intake chamber (6) is provided, one end of which is connected to the precooling structure (200) and communicates with the precooling bellows (5), and the other end of which is connected to the cooler body (100) so that the gas in the precooling bellows (5) enters the cooler body (100) through the air intake chamber (6).

3. The cooler according to claim 2, characterized in that, The air intake chamber (6) has a bent pipe structure so that the precooling structure (200) and the cooler body (100) are inclined to each other, and the precooling corrugated pipe (5) is inclined to the main cooling pipe (8) of the cooler body (100).

4. The cooler according to claim 3, characterized in that, The precooling structure (200) and the cooler body (100) are arranged perpendicularly to each other, and the precooling corrugated pipe (5) is arranged perpendicularly to the main cooling pipe (8).

5. The cooler according to claim 1, characterized in that, The precooling structure (200) includes an inlet flange (1) for connection to external components, the inlet flange (1) being disposed at the inlet end of the precooling bellows (5), and the precooling housing (2) being connected to the inlet flange (1); and / or The precooling structure (200) also includes: The first inflow section (3) is connected to the precooling shell (2) and communicates with the first cooling chamber, so that the first cooling medium enters the first cooling chamber from the first inflow section (3); The first outlet (4) is connected to the precooling shell (2) and communicates with the first cooling chamber, so that the first cooling medium that has completed heat exchange in the first cooling chamber flows out from the first outlet (4).

6. The cooler according to claim 1, characterized in that, The cooler is configured to communicate with a flow channel, and the precooling structure (200) includes a precooling bellows (5) which is configured to communicate with the flow channel; or The cooler is used to connect with two flow channels. The precooling structure (200) includes two precooling corrugated pipes (5). The two precooling corrugated pipes (5) are arranged in a one-to-one correspondence with the two flow channels. Each precooling corrugated pipe (5) is connected to the corresponding flow channel.

7. The cooler according to claim 1, characterized in that, The main body (100) of the cooler includes multiple main cooling pipes (8), an air inlet main plate (7), an air outlet main plate (12), and a main cooling shell (9). The air inlet main plate (7) and the air outlet main plate (12) are both connected to the main cooling shell (9) and together with the main cooling shell (9) form a second cooling chamber. The multiple main cooling pipes (8) are spaced apart in the second cooling chamber. One end of each main cooling pipe (8) is connected to the air inlet main plate (7), and the other end of each main cooling pipe (8) is connected to the air outlet main plate (12). Among them, multiple main cooling pipes (8) are plate-fin type cooling pipes, and fins are provided inside the main cooling pipes (8); or, the main cooling pipes (8) are pitted pipes.

8. The cooler according to claim 7, characterized in that, The cooler body (100) further includes a second inlet (10) and a second outlet (11). The second inlet (10) is connected to the main cold shell (9) and communicates with the second cooling chamber, so that the second cooling medium enters the second cooling chamber from the second inlet (10). The second outlet (11) is connected to the main cold shell (9) and communicates with the second cooling chamber, so that the second cooling medium that has completed heat exchange in the second cooling chamber flows out from the second inlet (10). The cooler also includes an air outlet chamber (13), which is connected to the main cooling housing (9) and is connected to a plurality of the main cooling pipes (8).

9. A waste gas recirculation system, characterized in that, The cooler includes any one of claims 1 to 8.

10. An engine, characterized in that, Includes the exhaust gas recirculation system as described in claim 9.

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