EGR cooler with high heat transfer performance trapezoidal fin

Abstract

The application discloses an EGR cooler with high heat exchange performance trapezoidal fin, and relates to the technical field of engine exhaust gas recirculation cooling, which comprises a shell, a heat exchange core, an exhaust gas outlet end cover and an exhaust gas inlet end cover, wherein the heat exchange core is arranged in the shell. The fin with the axial section in trapezoidal shape and the lateral section in asymmetric tooth groove shape is arranged in the heat exchange core, so that the exhaust gas heat exchange channels with the particle separation and flow guiding functions are formed between the adjacent fins. When normal heat exchange is performed, the lower flow guiding and limiting part guides the exhaust gas to the impact surface, the particles in the exhaust gas are separated from the main flow at the impact surface due to the inertial effect, the impacted exhaust gas re-enters the normal flow path through the flow guiding inclined surface and the upper backflow guiding part, so that the exhaust gas side disturbance and the heat exchange effect are improved, and the disorderly accumulation of the particles in the main flow heat exchange path is reduced.

Description

Technical Field

[0001] This invention relates to the field of engine exhaust gas recirculation cooling technology, and particularly to an EGR cooler with trapezoidal fins having high heat exchange performance. Background Technology

[0002] EGR coolers are used to cool the high-temperature exhaust gases in the engine's exhaust gas recirculation system, reducing the temperature of some exhaust gases before they re-enter the intake system, thereby improving the engine's combustion process and reducing emissions. Existing EGR coolers typically include a shell, a heat exchange core, an exhaust gas inlet end cap, an exhaust gas outlet end cap, and refrigerant passages. Exhaust gases flow within the heat exchange core, while refrigerant flows outside the core or in adjacent heat exchange passages to achieve heat exchange between the exhaust gases and the refrigerant. To improve heat exchange efficiency, existing heat exchange cores often incorporate fins, corrugated fins, or baffles to increase the heat exchange contact area and create some turbulence as the exhaust gases flow through the core.

[0003] However, EGR exhaust gas typically contains carbon soot particles, oil mist condensate, and other deposited impurities. During the cooling process, carbon deposits easily form inside the heat exchange core, especially at the fin roots, low-speed recirculation zone, and flow channel corners. Particles tend to adhere and gradually accumulate, reducing the effective flow cross-sectional area of ​​the exhaust gas heat exchange channel. This leads to increased exhaust gas flow resistance and decreased heat exchange efficiency, and in severe cases, it can even cause blockage of the heat exchange core. Ordinary fin structures are mainly used to increase the heat exchange area, but they have weak control over the location of particle deposition and lack a particle stripping structure to work with backflushing cleaning. Therefore, after long-term use, the problem of difficult-to-clean carbon deposits still exists.

[0004] Therefore, it is necessary to invent an EGR cooler with trapezoidal fins that have high heat exchange performance to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide an EGR cooler with trapezoidal fins having high heat exchange performance, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an EGR cooler with trapezoidal fins having high heat exchange performance, comprising a shell, a heat exchange core, an exhaust gas outlet end cap, and an exhaust gas inlet end cap, wherein the heat exchange core is disposed within the shell, and the exhaust gas outlet end cap and the exhaust gas inlet end cap are respectively connected to the two ends of the shell, wherein the heat exchange core is provided with a plurality of stacked fins, and an exhaust gas heat exchange channel is formed between adjacent fins along the exhaust gas flow direction; The fins are elongated heat exchange fins extending along the direction of exhaust gas flow. The axial cross-section of the fins is trapezoidal, and the lateral cross-section is asymmetrical toothed. In any of the exhaust gas heat exchange channels, the lower fins are provided with asymmetrical toothed grooves on the side facing the exhaust gas heat exchange channel. The two sides of the asymmetrical toothed grooves are respectively the impact surface facing the normal exhaust gas flow side and the backflow surface facing the backflow gas flow side. Both sides of the fins in the width direction are provided with particle storage inclined grooves communicating with the backflow surface. The upper fins are provided with an inclined block structure composed of an upper return flow guide and a lower flow guide and flow limiter on the side facing the exhaust gas heat exchange channel. The upper return flow guide is located above the impact surface, and the lower flow guide and flow limiter is located above the backflow surface. The exhaust gas inlet end cover is provided with a waste discharge port. The EGR cooler also includes a backflushing switching pipeline connected to the exhaust gas outlet end cover. During backflushing cleaning, the backflushing gas is discharged through the backflushing switching pipeline, the exhaust gas outlet end cover, the heat exchange core, the exhaust gas inlet end cover and the waste discharge port.

[0007] Preferably, the shell has end caps at both ends, and the two end caps seal the two ends of the heat exchange core respectively. The shell and the two end caps together form a refrigerant chamber that covers the heat exchange core. The shell has a refrigerant inlet and a refrigerant outlet that communicate with the refrigerant chamber.

[0008] Preferably, a plurality of the fins are stacked vertically at intervals along the height direction of the heat exchange core and fixed within the heat exchange core, and the length direction of the fins is consistent with the extension direction of the exhaust gas heat exchange channel.

[0009] Preferably, the lower flow guide and flow limiting part is inclined toward the direction of the impact surface, so as to guide the exhaust gas to the impact surface during normal heat exchange, so that the particulate matter in the exhaust gas is separated by impact at the impact surface.

[0010] Preferably, the top of the impact surface is provided with a guide slope, which is inclined toward the direction of the upper return flow guide, and is used to guide the exhaust gas impacting the impact surface to the upper return flow guide.

[0011] Preferably, the upper return flow guide is a sloped flow guide structure, which is used to receive the exhaust gas after it has been guided by the sloped flow guide and to return the exhaust gas to the normal flow path.

[0012] Preferably, the particle storage trough extends along the length of the fin, and the opening of the particle storage trough faces the area where the impact surface is located. The particle storage trough is used to store particles separated by the impact surface.

[0013] Preferably, the bottom of the particle storage trough is provided with a rounded transition section, and the width of the opening of the particle storage trough is greater than the width of its bottom, so as to reduce the risk of particle compaction and blockage in the particle storage trough.

[0014] Preferably, a diversion block is provided on the backflushing surface. The diversion block is located on the backflushing surface near the particle storage trough. The diversion block has an isosceles trapezoidal structure, and the width of the end of the diversion block near the exhaust gas heat exchange channel is greater than the width of the end near the backflushing surface. During backflushing cleaning, the backflushing gas passing through the backflushing surface impacts the wide end of the diversion block and is diverted along the two inclined sides of the diversion block to be guided into the particle storage trough on both sides of the fins.

[0015] Preferably, the backflushing switching pipeline includes a first tee flange, a second tee flange, and a backflushing connecting pipe. The first tee flange is connected to the second tee flange through the backflushing connecting pipe. The second tee flange is connected to the exhaust gas outlet end cover. The exhaust port is a valve-controlled port. The exhaust port is closed during normal heat exchange and opened during backflushing and ash removal.

[0016] The technical effects and advantages of this invention are as follows: 1. This invention provides a heat exchange channel for exhaust gas with particle separation and flow guidance functions by setting fins with a trapezoidal axial cross section and an asymmetrical toothed groove shape in the heat exchange core. During normal heat exchange, the lower flow guiding and limiting part guides the exhaust gas to the impact surface. The particles in the exhaust gas are separated from the mainstream due to inertia at the impact surface. The exhaust gas after impact returns to the normal flow path through the guide slope and the upper return flow guiding part. This improves the disturbance and heat exchange effect on the exhaust gas side while reducing the disorderly accumulation of particles in the mainstream heat exchange path. 2. This invention provides particle storage troughs connected to the backflushing surface on both sides of the fin width direction, allowing particles separated by the impact surface to enter the particle storage troughs for temporary storage. During backflushing cleaning, the backflushing gas flows rapidly along the backflushing surface and is guided to the particle storage troughs on both sides by the action of the diverter block, thereby entraining the particles in the particle storage troughs and carrying them out. The above structure enables the fins to not only have heat exchange function, but also particle separation, particle temporary storage and backflushing cleaning guidance functions, which is beneficial to delaying carbon blockage in the heat exchange core and the decay of heat exchange performance. 3. This invention forms a backflushing switching path through a first three-way flange, a backflushing connecting pipe, a second three-way flange, and a waste discharge port. During normal heat exchange, the waste discharge port is closed, and the waste gas passes through the heat exchange core along the conventional path. During backflushing cleaning, the waste discharge port is opened, and the backflushing gas enters the heat exchange core through the waste gas outlet end cover and exits through the waste gas inlet end cover, allowing the backflushing gas to flush the fin structure in the opposite direction to the normal waste gas. The above structure enables the cleaning of the fin particle storage area without disassembling the heat exchange core, which facilitates maintenance and improves the long-term stability of the EGR cooler. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0018] Figure 2 This is a schematic diagram of the backflush connection pipe structure of the present invention.

[0019] Figure 3 This is a cross-sectional schematic diagram of the shell structure of the present invention.

[0020] Figure 4 This is a schematic cross-sectional view of the shell structure of the present invention.

[0021] Figure 5 This is a schematic diagram showing the disassembled shell structure of the present invention.

[0022] Figure 6 This is a schematic diagram of the internal structure of the shell of the present invention.

[0023] Figure 7 This is a schematic diagram of the heat exchange core structure of the present invention.

[0024] Figure 8 This is a schematic diagram of the fin structure of the present invention. Figure 1 .

[0025] Figure 9 This is a schematic diagram of the fin structure of the present invention. Figure 2 .

[0026] Figure 10 This is a schematic diagram of the fin structure of the present invention. Figure 3 .

[0027] Figure 11 This is a side view of the heat exchange core structure of the present invention.

[0028] Figure 12 This is a diagram showing the forward trajectory of exhaust gas inside the exhaust gas channel of the present invention.

[0029] Figure 13 This is a diagram showing the backflow trajectory of exhaust gas inside the exhaust gas channel of the present invention.

[0030] In the diagram: 1. Shell; 11. End cap; 12. Refrigerant inlet; 13. Refrigerant outlet; 2. Heat exchange core; 21. Fin; 211. Impact surface; 2111. Guide slope; 212. Backflush surface; 2121. Diverter block; 213. Granule storage trough; 214. Upper reflux guide section; 215. Lower guide flow limiting section; 3. Exhaust gas outlet end cap; 4. Exhaust gas inlet end cap; 41. Waste discharge port; 5. First tee flange; 6. Second tee flange; 7. Backflush connection pipe. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figures 1 to 13 As shown, the EGR cooler with trapezoidal fins and high heat transfer performance provided by the present invention is essentially an EGR cooler structure that can guide the deposition position of particulate matter while maintaining high heat transfer performance, and can effectively entrain and discharge particulate matter during backflushing cleaning.

[0033] In terms of specific structural installation, the structural body can be constructed according to the inventive concept of this embodiment. In this embodiment, no special limitations are imposed.

[0034] In this embodiment, an EGR cooler with trapezoidal fins and high heat exchange performance includes a shell 1, a heat exchange core 2, an exhaust gas outlet end cap 3, and an exhaust gas inlet end cap 4. The heat exchange core 2 is disposed inside the shell 1. The shell 1 can be made of high-temperature resistant stainless steel plate, heat-resistant alloy plate, or other metal materials suitable for engine exhaust gas environment. The exhaust gas outlet end cap 3 is connected to one end of the shell 1, and the exhaust gas inlet end cap 4 is connected to the other end of the shell 1. The exhaust gas inlet end cap 4 is used to receive high-temperature exhaust gas from the engine EGR pipeline, and the exhaust gas outlet end cap 3 is used to discharge the exhaust gas cooled by the heat exchange core 2. The exhaust gas outlet end cap 3 and the exhaust gas inlet end cap 4 can be fixedly connected to the shell 1 by welding, bolting, flange pressing, or brazing to ensure good sealing of the exhaust gas flow path.

[0035] Both ends of the housing 1 are provided with end caps 11, which seal the two ends of the heat exchange core 2 respectively. The housing 1 and the two end caps 11 together form a refrigerant chamber covering the heat exchange core 2. The refrigerant chamber is used for the flow of coolant. The housing 1 is provided with a refrigerant inlet 12 and a refrigerant outlet 13 that communicate with the refrigerant chamber. The refrigerant inlet 12 can be located at the upper part of the housing 1 or near the high-temperature inlet area of ​​the exhaust gas. The refrigerant outlet 13 can be located at the lower part of the housing 1 or near the refrigerant outflow area. After the refrigerant enters the refrigerant chamber through the refrigerant inlet 12, it exchanges heat with the exhaust gas flowing in the heat exchange core 2 and then is discharged through the refrigerant outlet 13. The end caps 11 can adopt a plate-shaped sealing structure and be fixed to the housing 1 by welding, brazing or sealing and pressing to prevent refrigerant leakage.

[0036] The heat exchange core 2 is provided with multiple stacked fins 21. The fins 21 are individually processed sheet-like components. Multiple fins 21 are stacked vertically and fixed in the heat exchange core 2 along the height direction. Adjacent fins 21 form a heat exchange channel for exhaust gas that runs through the exhaust gas flow direction. The length direction of the fins 21 is consistent with the extension direction of the exhaust gas heat exchange channel. The fins 21 can be individually processed by stamping, bending, rolling or molding. Then they are assembled and fixed in the heat exchange core 2 by insertion, clamping, brazing, spot welding or limiting pressing to control their cross-sectional shape, groove size and flow guiding structure accuracy. The number of fins 21 and the stacking spacing can be adjusted according to the EGR flow requirements of different engines.

[0037] The fin 21 is a long strip-shaped heat exchange fin extending along the direction of exhaust gas flow. The axial section of the fin 21 is trapezoidal, and the lateral section is asymmetrical toothed. The axial section refers to the section formed by observation along the length of the fin 21 or the direction of exhaust gas flow. The trapezoidal structure enables the fin 21 to form a large heat exchange contact area in the exhaust gas heat exchange channel, and generates a guiding and turbulent effect on the exhaust gas through the trapezoidal edge. The lateral section refers to the section formed by observation perpendicular to the length of the fin 21. The asymmetrical toothed structure enables the fin 21 to have different guiding responses in the direction of normal exhaust gas flow and the direction of backflow gas flow, thereby realizing the separation of forward-flowing particles and the removal of backflowing particles.

[0038] In any waste gas heat exchange channel, the lower fin 21 is provided with an asymmetrical toothed groove on the side facing the waste gas heat exchange channel. The two sides of the asymmetrical toothed groove are the impact surface 211 and the backflow surface 212, respectively. The impact surface 211 faces the normal waste gas inflow side, and the backflow surface 212 faces the backflow gas inflow side. During normal heat exchange, the waste gas enters the heat exchange core 2 through the waste gas inlet end cover 4 and flows to the waste gas outlet end cover 3 in the waste gas heat exchange channel between adjacent fins 21. During backflow cleaning, the backflow gas enters the heat exchange core 2 through the waste gas outlet end cover 3 and flows to the waste gas inlet end cover 4 in the opposite direction to the normal waste gas.

[0039] Particle storage troughs 213 are provided on both sides of the fin 21 in the width direction. The particle storage troughs 213 are connected to the backflushing surface 212. The particle storage troughs 213 extend along the length direction of the fin 21, and their openings face the area where the backflushing surface 212 is located. During normal heat exchange, the particles in the exhaust gas are separated by the impact surface 211 and can migrate to the particle storage troughs 213 on both sides of the fin 21 in the width direction and be temporarily stored. The particle storage troughs 213, the impact surface 211 and the backflushing surface 212 cooperate to form a controlled particle storage area. In order to reduce the compaction and coking of particles at the bottom of the trough, the bottom of the particle storage trough 213 can be provided with a rounded transition part, and the width of the opening of the particle storage trough 213 is greater than the width of its bottom, so that the particles can enter the particle storage trough 213 and be more easily carried out under the action of the backflushing gas.

[0040] The upper fin 21 has an inclined block structure on one side facing the same exhaust gas heat exchange channel, consisting of an upper reflux guide 214 and a lower flow guide and limiter 215. The upper reflux guide 214 is located above the impact surface 211, and the lower flow guide and limiter 215 is located above the backflow surface 212. The lower flow guide and limiter 215 is inclined towards the impact surface 211 and is used to guide the exhaust gas to the impact surface 211 during normal heat exchange, so that the particulate matter in the exhaust gas is separated by impact at the impact surface 211. The top of the impact surface 211 is provided with a flow guide slope 2111, which is inclined towards the upper reflux guide 214 and is used to guide the exhaust gas after impacting the impact surface 211 to the upper reflux guide 214. The upper reflux guide 214 is an inclined flow guide structure, which is used to receive the exhaust gas guided by the flow guide slope 2111 and return the exhaust gas to the normal flow path.

[0041] A diversion block 2121 is provided on the backflushing surface 212. The diversion block 2121 is located on the backflushing surface 212 near the particle storage trough 213. The diversion block 2121 has an isosceles trapezoidal structure, and the width of the end of the diversion block 2121 near the exhaust gas heat exchange channel is greater than the width of the end near the backflushing surface 212. The wide end of the diversion block 2121 faces the exhaust gas heat exchange channel, and the narrow end is close to or connected to the backflushing surface 212. During backflushing and cleaning, the backflushing gas passing through the backflushing surface 212 impacts the wide end of the diversion block 2121 and is diverted along the two inclined sides of the diversion block 2121. It is then guided to the particle storage trough 213 on both sides of the width direction of the fin 21, thereby generating a suction and entrainment effect on the particles temporarily stored in the particle storage trough 213.

[0042] The exhaust gas inlet end cover 4 is equipped with an exhaust port 41. The exhaust port 41 is a valve-controlled port. During normal heat exchange, the exhaust port 41 is closed, allowing the exhaust gas to enter the heat exchange core 2 through the exhaust gas inlet end cover 4 and exit through the exhaust gas outlet end cover 3. During backflushing and cleaning, the exhaust port 41 is opened and can be connected to the exhaust pipe to discharge the backflushing gas and its entrained particles. An external exhaust pipe can be connected to the exhaust port 41 so that the backflushing gas and its entrained particles discharged from the exhaust gas inlet end cover 4 during the backflushing and cleaning process are not directly discharged into the external environment. In one embodiment, the exhaust port 41 can be an electronically controlled valve interface, a pneumatic valve interface, a mechanical valve interface, or an external exhaust valve interface. The exhaust port 41 is connected to a high-temperature resistant exhaust pipeline. The high-temperature resistant exhaust pipeline can be equipped with a shut-off valve, a check valve, a particle settling tank, a high-temperature filter cartridge, and a return pipe. The shut-off valve is used to close the exhaust port 41 during normal heat exchange. The check valve is used to prevent the gas in the exhaust pipeline from flowing back. The particle settling tank and the high-temperature filter cartridge are used to settle and filter the particles carried by the backflow gas. The return pipe is used to connect the filtered backflow gas back to the low-pressure section of the engine exhaust pipeline or the front end of the aftertreatment device, so that the backflow gas and its carried particles are collected or reconnected for treatment after entering the external exhaust pipeline through the exhaust port 41, thereby ensuring that the backflow cleaning process forms a closed-loop emission path.

[0043] The EGR cooler also includes a backflushing switching pipeline connected to the exhaust gas outlet end cover 3. The backflushing switching pipeline includes a first three-way flange 5, a second three-way flange 6, and a backflushing connecting pipe 7. The first three-way flange 5 is connected to the second three-way flange 6 through the backflushing connecting pipe 7. The second three-way flange 6 is connected to the exhaust gas outlet end cover 3. During normal heat exchange, the first three-way flange 5 and the second three-way flange 6 are in the normal heat exchange path. The exhaust gas flows in the direction of the exhaust gas inlet end cover 4, the heat exchange core 2, and the exhaust gas outlet end cover 3. The exhaust port 41 is closed. During backflushing cleaning, the first three-way flange 5 and the second three-way flange 6 are switched to the backflushing cleaning path. The exhaust port 41 is opened. The backflushing gas enters the heat exchange core 2 through the first three-way flange 5, the backflushing connecting pipe 7, the second three-way flange 6, and the exhaust gas outlet end cover 3 in sequence, and then exits through the exhaust gas inlet end cover 4 and the exhaust port 41.

[0044] In summary, during normal heat exchange, high-temperature EGR exhaust gas enters the exhaust gas heat exchange channel within the heat exchange core 2 through the exhaust gas inlet end cap 4. Because the lower flow guide and restrictor 215 is inclined towards the impact surface 211, the exhaust gas, after entering between adjacent fins 21, is guided by the lower flow guide and restrictor 215 to the impact surface 211. When the exhaust gas impacts the impact surface 211, carbon soot particles, oil mist condensates, and other particulate matter in the exhaust gas separate from the mainstream airflow due to inertia, and some of these particles enter the fins 21. The particles are temporarily stored in the inclined storage troughs 213 on both sides of the width direction. After impact, the exhaust gas continues to move upward backflow guide 214 through the guide inclined surface 2111 at the top of the impact surface 211. Under the action of the upper backflow guide 214, it returns to the normal flow path of the exhaust gas heat exchange channel. At the same time, the refrigerant enters the refrigerant chamber formed by the shell 1 and the end cover 11 through the refrigerant inlet 12 and exchanges heat with the exhaust gas in the heat exchange core 2. After heat exchange, the refrigerant is discharged through the refrigerant outlet 13.

[0045] During the backflushing cleaning process, the first three-way flange 5 and the second three-way flange 6 are switched to the backflushing cleaning passage, the waste discharge port 41 is opened, and the backflushing gas enters the exhaust gas outlet end cover 3 through the first three-way flange 5, the backflushing connecting pipe 7 and the second three-way flange 6, and then enters the heat exchange core 2 through the exhaust gas outlet end cover 3. The backflushing gas flows in the heat exchange core 2 in the opposite direction to the normal exhaust gas and passes quickly along the backflushing surface 212. When the backflushing gas passes through the backflushing surface 212, it is affected by the diversion block 2121. The isosceles trapezoidal wide end of the diversion block 2121 first bears the impact of the backflushing airflow, and the airflow enters the particle storage troughs 213 on both sides of the fin 21 along the two inclined sides. The backflushing gas entering the particle storage troughs 213 carries the temporarily stored particles, causing the particles to leave the particle storage troughs 213 and move towards the exhaust gas inlet end cover 4 with the backflushing airflow, and finally is discharged through the waste discharge port 41.

[0046] Through the above-described structure, the present invention enables the fins 21 to not only serve as trapezoidal heat exchange fins to increase the heat exchange area on the exhaust side during normal heat exchange, but also to perform impact separation and directional temporary storage of particulate matter through the asymmetric toothed groove structure. During the backflushing cleaning process, the backflushing surface 212 and the diversion block 2121 can be used to guide the backflushing gas into the particulate storage chute 213 to achieve the entrainment and removal of particulate matter. This structure helps to reduce the risk of carbon buildup and blockage in the EGR cooler during long-term use, delay the decline in heat exchange performance, and improve the maintenance convenience and operational stability of the EGR cooler.

[0047] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An EGR cooler with trapezoidal fins having high heat exchange performance, comprising a shell (1), a heat exchange core (2), an exhaust gas outlet end cap (3), and an exhaust gas inlet end cap (4), wherein the heat exchange core (2) is disposed within the shell (1), and the exhaust gas outlet end cap (3) and the exhaust gas inlet end cap (4) are respectively connected to both ends of the shell (1), characterized in that: The heat exchange core (2) is provided with multiple stacked fins (21), and a heat exchange channel for exhaust gas is formed between adjacent fins (21) along the direction of exhaust gas flow. The fin (21) is a long strip-shaped heat exchange fin extending along the direction of exhaust gas flow. The axial cross-section of the fin (21) is trapezoidal, and the lateral cross-section is asymmetrical toothed. In any of the exhaust gas heat exchange channels, the lower fin (21) has an asymmetrical toothed groove on the side facing the exhaust gas heat exchange channel. The two sides of the asymmetrical toothed groove are the impact surface (211) facing the normal exhaust gas flow side and the backflow surface (212) facing the backflow gas flow side. Both sides of the fin (21) in the width direction are provided with particle storage troughs (213) that communicate with the backwash surface (212). The upper fin (21) facing the exhaust gas heat exchange channel is provided with a sloping block structure composed of an upper reflux guide (214) and a lower flow guide and flow limiter (215). The upper reflux guide (214) is located above the impact surface (211), and the lower flow guide and flow limiter (215) is located above the backwash surface (212). The exhaust gas inlet end cap (4) is provided with a waste discharge port (41). The EGR cooler also includes a backflushing switching pipeline connected to the exhaust gas outlet end cap (3). During backflushing cleaning, the backflushing gas is discharged through the backflushing switching pipeline, the exhaust gas outlet end cap (3), the heat exchange core (2), the exhaust gas inlet end cap (4) and the waste discharge port (41).

2. An EGR cooler with trapezoidal fins and high heat transfer performance according to claim 1, characterized in that: Both ends of the housing (1) are provided with end caps (11), and the two end caps (11) respectively seal the two ends of the heat exchange core (2). The housing (1) and the two end caps (11) together form a refrigerant chamber covering the heat exchange core (2). The housing (1) is provided with a refrigerant inlet (12) and a refrigerant outlet (13) communicating with the refrigerant chamber.

3. An EGR cooler with trapezoidal fins and high heat transfer performance according to claim 1, characterized in that: Multiple fins (21) are stacked vertically at intervals along the height direction of the heat exchange core (2) and fixed inside the heat exchange core (2). The length direction of the fins (21) is consistent with the extension direction of the exhaust gas heat exchange channel.

4. An EGR cooler with trapezoidal fins and high heat transfer performance according to claim 1, characterized in that: The lower flow guide and flow limit section (215) is inclined toward the direction of the impact surface (211) to guide the exhaust gas to the impact surface (211) during normal heat exchange, so that the particulate matter in the exhaust gas is separated by impact at the impact surface (211).

5. An EGR cooler with trapezoidal fins and high heat transfer performance according to claim 4, characterized in that: The top of the impact surface (211) is provided with a guide slope (2111), which is inclined toward the direction of the upper return flow guide (214) to guide the exhaust gas impacting the impact surface (211) to the upper return flow guide (214).

6. An EGR cooler with trapezoidal fins having high heat transfer performance according to claim 5, characterized in that: The upper return flow guide (214) is a sloped flow guide structure. The upper return flow guide (214) is used to receive the exhaust gas after it has been guided by the sloped flow guide (2111) and to return the exhaust gas to the normal flow path.

7. An EGR cooler with trapezoidal fins having high heat transfer performance according to claim 1, characterized in that: The particle storage chute (213) extends along the length of the fin (21), and the opening of the particle storage chute (213) faces the area where the impact surface (212) is located. The particle storage chute (213) is used to store particles separated by the impact surface (211).

8. An EGR cooler with trapezoidal fins having high heat transfer performance according to claim 7, characterized in that: The bottom of the particle storage trough (213) is provided with a rounded transition section, and the width of the opening of the particle storage trough (213) is greater than the width of its bottom, so as to reduce the risk of particle material being compacted and blocked in the particle storage trough (213).

9. An EGR cooler with trapezoidal fins having high heat transfer performance according to claim 1, characterized in that: A diversion block (2121) is provided on the backwash surface (212). The diversion block (2121) is located on the backwash surface (212) near the particle storage trough (213). The diversion block (2121) has an isosceles trapezoidal structure, and the width of the end of the diversion block (2121) near the exhaust gas heat exchange channel is greater than the width of the end near the backwash surface (212). During backwash cleaning, the backwash gas passing through the backwash surface (212) impacts the wide end of the diversion block (2121) and is diverted along the two inclined sides of the diversion block (2121) to be guided into the particle storage trough (213) on both sides of the fin (21).

10. An EGR cooler with trapezoidal fins having high heat transfer performance according to claim 1, characterized in that: The backflushing switching pipeline includes a first tee flange (5), a second tee flange (6), and a backflushing connecting pipe (7). The first tee flange (5) is connected to the second tee flange (6) through the backflushing connecting pipe (7). The second tee flange (6) is connected to the exhaust gas outlet end cap (3). The exhaust port (41) is a valve-controlled port. During normal heat exchange, the exhaust port (41) is closed, and during backflushing and ash removal, the exhaust port (41) is opened.

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