Exhaust gas recirculation cooler with split exhaust main plate

Abstract

The present invention relates to an exhaust gas recirculation cooler using a split air outlet main plate, the cooler includes an air inlet chamber, an air inlet main plate, an air inlet sealing pad, a heat dissipation pipe group, a shell, an air outlet main plate, an air outlet sealing pad and an air outlet chamber, the air outlet main plate includes an insert and a diaphragm, an insert mounting hole is provided in the middle of the diaphragm, the insert mounting hole is vertically provided with a flange structure on the side away from the heat dissipation pipe group installation, and the insert is fixedly arranged on the flange structure of the insert mounting hole. The air outlet main plate assembly adopts a combined structure, the thicker insert can ensure the laser welding strength, and the thinner diaphragm can play a role similar to a "spring", which can effectively compensate for the deformation caused by the thermal expansion of the heat dissipation pipe, release thermal stress, and greatly reduce the risk of fatigue fracture. The design of this structure is suitable for heat dissipation pipes of different lengths, and the longer the heat dissipation pipe, the more obvious the effect of reducing thermal shock failure. The test results show that the use of the air outlet main plate of the present invention can reduce 20% to 30% of the thermal shock stress, and the heat shock resistance life of the cooler is increased by about 43%.

Description

Technical Field

[0001] The invention relates to an exhaust gas recirculation cooler for a commercial vehicle using a split-type air outlet main plate, and in particular to an exhaust gas recirculation cooler using a split-type air outlet main plate. Background Art

[0002] As an emerging engine in-engine purification technology, the exhaust gas recirculation (EGR) system has become an important means of reducing NOx emissions together with the three-way catalytic converter (SCR) technology. Its principle is to cool the exhaust gas generated after engine combustion and return it to the combustion chamber. Since the exhaust gas is inert, it does not participate in the combustion in the combustion chamber, but it can dilute the mixed gas, reduce the oxygen concentration and the maximum combustion temperature, thereby achieving the purpose of reducing NOx generation. The exhaust gas recirculation (EGR) cooler is a device for reducing the exhaust gas temperature in the exhaust gas recirculation system. After the exhaust gas is cooled, the pressure rise rate and peak pressure at the beginning of combustion can be reduced, the fresh air throttling loss can be reduced, and the intake charge can be increased, thereby extending the combustion delay period, increasing the proportion of premixed combustion, shortening the combustion duration, reducing the maximum combustion temperature, and reducing NOx emissions. For the sake of convenience, the exhaust gas recirculation (EGR) cooler is referred to as the EGR cooler below.

[0003] The main plate of the EGR cooler is usually assembled in the shell with the heat dissipation tube group by welding. It is divided into the intake main plate and the exhaust main plate according to the exhaust gas flow direction. The heat dissipation tube group is the exhaust gas channel, and the coolant flows around the heat dissipation tube group for heat exchange. Its main functions include: ensuring the installation strength of the heat dissipation tube group so that it has good heat shock resistance; ensuring the spacing between adjacent heat dissipation tubes in the heat dissipation tube group so that the flow rate and distribution of the coolant are more uniform, thereby achieving good heat exchange efficiency.

[0004] At present, most EGR coolers use the main plate and installation form such as Fig.13 As shown, the intake main plate and the exhaust main plate have the same thickness and structure, and the thickness is generally 2 to 3 mm. They are assembled in the shell after being welded with the heat pipe. The maximum temperature of the exhaust gas after combustion in commercial vehicles can reach 600 to 700 ° C, and it will fluctuate with the changes in the working conditions of the whole vehicle. The thermal shock caused by the irregularly changing high-temperature exhaust gas is an important cause of the failure of the EGR cooler. According to the thermal expansion calculation formula, the thermal expansion (or contraction) length ΔL = L 1 *α*ΔT(L 1is the length of the heat dissipation pipe, α is the thermal expansion coefficient, △T is the temperature difference), when the heat dissipation pipe length is less than 350mm, the thermal expansion △L is relatively small, and this main plate can basically meet the requirements of thermal shock resistance; but when the heat dissipation pipe length is greater than 350mm, or longer, the degree of thermal expansion and contraction increases, and the deformation of the main plate of this thickness cannot compensate for the thermal expansion deformation, and the stress cannot be released. Fatigue cracking may occur at the weld of the heat dissipation pipe and the main plate, and the coolant may flow into the air side channel, which may eventually cause the turbocharger or even the cylinder to enter the water, causing the whole vehicle to fail. Therefore, improving the structure of the main plate so that it can effectively release the thermal shock stress while ensuring strength and assembly accuracy is an important measure to reduce the thermal shock failure of the EGR cooler. Summary of the invention

[0005] In order to solve the above problems, the present invention provides an exhaust gas recirculation cooler with a split air outlet main plate. Under the premise of ensuring assembly strength and accuracy, the thermal expansion of the heat dissipation pipe is compensated by better elastic deformation, which can effectively reduce the stress of thermal shock on the main plate and the heat dissipation pipe welds, thereby reducing the risk of failure.

[0006] The technical solution adopted by the present invention is: an exhaust gas recirculation cooler adopting a split air outlet main plate, comprising an air inlet chamber, an air inlet main plate, an air inlet sealing pad, a heat dissipation pipe group, a shell, an air outlet main plate, an air outlet sealing pad and an air outlet chamber, wherein the air inlet side of the shell is provided with an air inlet chamber, and the air outlet side is provided with an air outlet chamber; an air inlet main plate is provided between the air inlet chamber and the shell, and an air inlet sealing pad is provided between the air inlet main plate and the air inlet chamber and the shell; an air outlet main plate is provided between the air outlet chamber and the shell, and the air outlet main plate is provided with an air outlet seal. An air outlet sealing pad is provided between the air chamber and the shell; the heat dissipation pipe group is arranged in the shell and is correspondingly connected to the air holes of the air inlet main plate and the air outlet main plate; a water inlet is provided on the air inlet side of the shell, and a water outlet is provided on the air outlet side; it is characterized in that: the air outlet main plate includes an insert and a diaphragm, the diaphragm is fixed between the shell and the air outlet chamber, an insert mounting hole is provided in the middle, the insert mounting hole is vertically provided with a flange structure on the side away from the installation of the heat dissipation pipe group, and the insert is fixedly arranged on the flange structure of the insert mounting hole.

[0007] Preferably, the thickness of the diaphragm is 0.8 mm, the height of the flange structure is 4.5 mm, and the thickness of the insert is 2 mm.

[0008] Preferably, the insert is fixedly mounted on the top of the flange structure, and the height difference with the top is no more than 0.1 mm.

[0009] Preferably, the maximum assembly gap around the insert and the flange structure is 0.1 mm.

[0010] Preferably, the insert and the diaphragm are pre-assembled first, with the pre-assembly pull-off force being greater than 90N; and then fixed by laser welding.

[0011] Preferably, the flange surface on the air outlet side of the shell is provided with two pins which are mounted in cooperation with the diaphragm.

[0012] Preferably, the flange surface on the air outlet side of the shell is provided with a chamfer of 10 mm.

[0013] Preferably, the air intake chamber adopts a double-channel exhaust gas inlet, and a baffle is cast between the double channels.

[0014] Preferably, the water inlet is arranged at the lower part of the air inlet side of the shell, and the water outlet is arranged at the upper part of the air outlet side of the shell.

[0015] Preferably, the heat dissipation pipe is a pitted heat dissipation pipe.

[0016] The beneficial effects achieved by the present invention are: by adopting a combined structure (insert and diaphragm split structure) for the outlet main plate, and providing an insert mounting hole with a flange structure in the middle of the diaphragm, the present invention can effectively reduce the stress of the main plate and the heat pipe weld caused by thermal shock under the premise of ensuring assembly strength and accuracy through better elastic deformation compensation of the heat expansion of the heat pipe, thereby reducing the risk of failure. Tests show that the main plate of the present invention can increase the heat shock resistance life of the EGR cooler by about 43%. The present invention has the following advantages:

[0017] 1. The exhaust main plate assembly adopts a combined structure, which is composed of a 2mm thick insert and a 0.8mm diaphragm. The maximum temperature of the circulating exhaust gas can reach 600-700℃, and will fluctuate with the changes in the working conditions of the whole vehicle. The heat dissipation pipe group will produce irregular thermal expansion and contraction deformation; the welds of the exhaust main plate and the heat dissipation pipe group may cause fatigue fracture due to the alternating stress generated by the reciprocating deformation. The exhaust main plate adopts a 2mm thick insert to ensure the laser welding strength, and the 0.8mm thick diaphragm can play a role similar to a "spring", which can effectively compensate for the deformation caused by the thermal expansion and contraction of the heat dissipation pipe group, release thermal stress, and greatly reduce the risk of fatigue fracture; the exhaust main plate of the present invention can reduce the thermal shock stress by 20%-30%, and increase the thermal shock life of the EGR cooler by about 43%. By using a variety of diaphragms of different thicknesses for simulation tests and bench verification, it is determined that the thickness of 0.8mm is the best choice;

[0018] 2. The assembly position of the diaphragm and the insert adopts a flange structure with a height of 4.5mm. The flange direction forms a 90° angle with the diaphragm. This design can effectively reduce the local torque deformation of the diaphragm, concentrate the deformation in the direction of thermal expansion of the heat pipe group, and then release the thermal expansion stress through the "elastic" deformation of the diaphragm, thereby reducing the risk of cracking of the weld or the main piece;

[0019] 3. After the insert and the diaphragm are pre-assembled, the gap between them is no more than 0.1mm, and the height difference is no more than 0.1mm. This requirement can ensure the pre-assembly accuracy, thereby ensuring the stability and strength of the laser welding at the weld and improving the thermal durability of the EGR cooler;

[0020] 4. The thickness of the air intake main plate is 2mm, which can ensure the assembly strength and thermal durability of the high-temperature side, and concentrate the thermal expansion generated by the heat dissipation pipe group to compensate through the elastic deformation of the air outlet main plate;

[0021] 5. Two pins are provided on the flange surface of the gas outlet side of the shell, which are installed in conjunction with the pin holes on the gas outlet main plate to reduce the thermal deformation of the gas outlet main plate during laser welding. As the thickness of the diaphragm decreases, the degree of thermal deformation increases under the high temperature environment generated by laser welding. The pins distributed on both sides of the gas outlet main plate can limit the thermal distortion of the main plate and ensure its flatness and sealing requirements.

[0022] 6. The flange surface on the outlet side of the shell is set with a large chamfer of 10mm, which provides space for the "elastic" deformation of the outlet main plate and is conducive to the further release of thermal stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention;

[0024] Figure 2 It is a cross-sectional view of an exhaust gas recirculation cooler using a split-type air outlet main plate of the present invention;

[0025] Figure 3 for Figure 2 A local enlarged view of point C in FIG.

[0026] Figure 4 This is a schematic diagram of the main exhaust plate structure;

[0027] Figure 5 is a schematic diagram of the diaphragm structure;

[0028] Figure 6 is a schematic diagram of the insert structure;

[0029] Figure 7 It is the technical requirement drawing for assembling the main exhaust plate;

[0030] Figure 8 This is a schematic diagram of the main intake plate structure;

[0031] Fig. 9 This is a schematic diagram of the assembly of the main exhaust plate and the shell;

[0032] Fig.10 This is a schematic diagram of the assembly of the air intake main plate and the housing;

[0033] Fig.11This is the thermal shock deformation diagram of the heat pipe and the main plate (displacement magnification: 100 times);

[0034] Fig.12 This is a partial enlarged view of the deformation of the main exhaust plate (displacement magnification: 100 times);

[0035] Fig.13 This is a schematic diagram of the installation of the traditional EGR cooler gas main plate;

[0036] Fig.14 This is a schematic diagram of the EGR cooler thermal shock test conditions;

[0037] Wherein: 1. air inlet chamber; 2. air inlet sealing gasket; 3. air inlet main plate; 4. air inlet sealing gasket; 5. heat dissipation pipe group; 6. side bracket mounting hole; 7. water outlet; 8. air outlet sealing gasket; 9. air outlet main plate; 10. air outlet sealing gasket; 11. air outlet chamber; 12. bottom bracket mounting hole; 13. shell; 14. water inlet; 15. weld between insert and heat dissipation pipe; 16. weld between insert and diaphragm; 17. weld between air inlet main plate and heat dissipation pipe; 18. pin on air outlet side; 19. pin on air inlet side; 20. insert; 21. diaphragm; 211. insert mounting hole; 212. flanging structure; 22. chamfer of flange surface on shell air outlet side; A. exhaust gas inlet; B. exhaust gas outlet. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0039] like Fig.13 As shown, the intake main plate 3 and the outlet main plate 9 of the conventional EGR cooler have the same thickness and the same structure, and the thickness is generally 2-3 mm. They are assembled in the housing 13 after being welded with the heat dissipation pipe group 5. The maximum temperature of the exhaust gas after combustion of commercial vehicles can reach 600-700°C, and will fluctuate with the changes in the working conditions of the whole vehicle. The thermal shock caused by the irregularly changing high-temperature exhaust gas is an important inducement for the failure of the EGR cooler. When the length of the heat dissipation pipe is less than 350mm, the thermal expansion △L is relatively small, and this main plate can basically meet the requirements of thermal shock resistance; but when the length of the heat dissipation pipe is greater than 350mm, or longer, the degree of thermal expansion and contraction increases, and the deformation of the main plate of this thickness cannot compensate for the thermal expansion deformation, and the stress cannot be released. Fatigue cracking may occur at the weld of the heat dissipation pipe group 5 and the main plate (the intake main plate 3 and the outlet main plate 9), and the coolant will flow into the gas side channel, which may eventually cause the turbocharger or even the cylinder to enter the water, causing the whole vehicle failure.

[0040] like Figure 1-12As shown, an exhaust gas recirculation cooler using a split air outlet main plate of the present invention comprises an air inlet chamber 1, an air inlet main plate 3, an air inlet sealing gasket 2 (4), a heat dissipation pipe group 5, a shell 13, an air outlet main plate 9, an air outlet sealing gasket 8 (10) and an air outlet chamber 11, wherein the air inlet chamber 1 is fixedly arranged on the air inlet side flange surface of the shell 13, and the air outlet chamber 11 is fixedly arranged on the air outlet side flange surface of the shell 13; the air inlet main plate 3 is fixedly arranged between the air inlet chamber 1 and the air inlet side flange surface of the shell 13, an air inlet sealing gasket 2 is arranged between the air inlet main plate 3 and the air inlet chamber 1, and the air inlet main plate 3 and the shell 13 are fixedly arranged between the air inlet chamber 1 and the air inlet side flange surface of the shell 13. An air intake sealing gasket 4 is provided between the air intake side flange surface of the shell 13; an air outlet main plate 9 is fixedly arranged between the air outlet chamber and the air outlet side flange surface of the shell 13, an air outlet sealing gasket 10 is provided between the air outlet main plate 9 and the air outlet chamber 11, and an air outlet sealing gasket 8 is provided between the air outlet main plate 9 and the air outlet side flange surface of the shell 13; a heat dissipation pipe group 5 is arranged in the shell 13, and is composed of a plurality of heat dissipation pipes, one end of which is inserted into the air hole corresponding to the air intake main plate 3 and fixed by welding, and the other end is inserted into the air hole corresponding to the air outlet main plate 9 and fixed by welding; a water inlet 14 is provided on the air intake side of the shell 12, and a water outlet 7 is provided on the air outlet side. High-temperature circulating exhaust gas (600-700°C) is introduced from the air inlet chamber 1, passes through the heat dissipation pipe group 5 in the shell 13, and is discharged from the air outlet chamber 11; relatively low-temperature coolant (85-95°C) flows into the shell from the water inlet 14 and is discharged from the water outlet 7; when the circulating exhaust gas flows through the heat dissipation pipe group 5, it exchanges heat with the coolant outside the pipe.

[0041] The air outlet main piece 9 includes an insert 20 and a diaphragm 21. The diaphragm 21 is fixed between the shell 13 and the air outlet chamber 11. An insert mounting hole 211 is provided in the middle. The insert mounting hole 211 is vertically provided with a flange structure 212 on the side away from the installation of the heat dissipation tube group. The insert 20 is fixedly set on the flange structure 212 of the insert mounting hole 211.

[0042] In this embodiment, the diaphragm 21 has a thickness of 0.8 mm and a 4.5 mm flange structure in the middle area. The flange direction forms a 90° angle with the diaphragm, and the flange root radius is R1.2; the insert 20 has a thickness of 2 mm and is assembled in the flange structure of the diaphragm 21 and connected to the diaphragm 20 by laser welding (such as Fig. 9 As shown, the weld is 16); the insert 20 and the diaphragm 21 are pre-assembled first, and then laser welding is completed. The pre-assembly requires a pull-off force greater than 90N (the lowest pull-off force is 2.5 times the total tube bundle mass); after the insert 20 and the diaphragm 21 are pre-assembled, the maximum assembly gap around the insert 21 is 0.1mm, and after pre-assembly, the height difference between the insert 20 and the diaphragm 21 in the assembly direction of the heat dissipation tube 5 is not greater than 0.1mm (the insert 20 is fixedly installed at the top of the flange structure 212, and the height difference with the top is not greater than 0.1mm). The flange surface on the outlet side of the shell 13 is provided with a 10mm chamfer 22, which provides space for the "elastic" deformation of the outlet main plate 9, which is conducive to the further release of thermal stress.

[0043] In this embodiment, combined with Fig. 9 As shown, pins 18 are arranged on both sides of the flange surface of the air outlet side of the housing 13, and are installed in conjunction with the air outlet main plate assembly 9. The pins 18 are used to reduce the thermal deformation of the air outlet main plate 9 during the laser welding process. The thickness of the diaphragm 21 is reduced, and the degree of thermal deformation increases under the high temperature environment generated by laser welding. The pins distributed on both sides of the air outlet main plate 9 can limit the heat distortion of the main plate and ensure its flatness and sealing requirements. Fig.10 As shown, pins 19 are provided on both sides of the flange surface of the housing 13 on the air intake side, and are installed in coordination with the air intake main plate 3 .

[0044] In this embodiment, the air intake chamber 1 adopts a dual-channel exhaust gas inlet, each channel is connected to the exhaust ports of three cylinders, and a baffle is cast in the air intake chamber 1 to ensure that the dual channels independently pass the exhaust gas.

[0045] In this embodiment, the housing 13 is provided with bracket mounting holes, including two bottom bracket mounting holes 12 and two side bracket mounting holes 6, which are respectively fixed to the engine body by bolts.

[0046] The shell 13 adopts an "S"-shaped flow channel, that is, the water inlet 14 is located at the lower part of the air inlet side of the shell 13, and the water outlet 7 is arranged at the upper part of the air outlet side of the shell.

[0047] In this embodiment, the housing 13 and the air outlet flange 11 are made of aluminum, and the remaining components are made of stainless steel. This can reduce the weight of the cooler while ensuring that the ambient temperature requirements are met.

[0048] In this embodiment, the heat dissipation tube group 5 uses a pitted heat dissipation tube, which can increase the heat exchange area and achieve better cross-flow of the coolant, higher heat exchange efficiency, and can limit the deposition of carbon soot particles, enhance the installation strength of the tube bundle, and improve the thermal durability of the heat dissipation tube.

[0049] Compared with the main plate of the same thickness and structure used in the current EGR cooler, the outlet main plate 9 of the present invention adopts a combined structure, which is composed of a 2mm thick insert 20 and a 0.8mm diaphragm 21. The maximum temperature of the circulating exhaust gas can reach 600-700℃, and will fluctuate with the change of the working conditions of the whole vehicle. The heat dissipation pipe will produce irregular thermal expansion deformation. The alternating stress generated by the reciprocating deformation of the weld of the outlet main plate 9 and the heat dissipation pipe may cause fatigue fracture. The 2mm thick insert 20 of the outlet main plate of the present invention can ensure the laser welding strength, and the 0.8mm thick diaphragm 21 can play a role similar to a "spring", which can effectively compensate for the deformation caused by the thermal expansion of the heat dissipation pipe, release thermal stress, and greatly reduce the risk of fatigue fracture. The design of this structure is suitable for heat dissipation pipes of different lengths, and the longer the heat dissipation pipe, the more obvious the effect of reducing thermal shock failure. The test results show that the use of the outlet main plate 9 of the present invention can reduce 20%-30% of the thermal shock stress and increase the heat shock resistance life of the EGR cooler by about 43%.

[0050] The flange structure 212 is used at the assembly position of the diaphragm 21 and the insert 20. This design can effectively reduce the local torque deformation of the diaphragm 21, concentrate the deformation in the direction of thermal expansion of the heat pipe, and then release the thermal expansion stress through the "elastic" deformation of the diaphragm 21, thereby reducing the risk of cracking of the weld or the main piece.

[0051] Unlike the diaphragm 21 of the outlet main plate 9 which has a thickness of 0.8 mm, the thickness of the inlet main plate 3 is 2 mm. This combination can ensure the assembly strength and thermal durability of the high-temperature side, and concentrate the thermal expansion generated by the heat pipe to be compensated through the elastic deformation of the outlet main plate assembly.

[0052] The flange surface on the outlet side of the housing 13 is provided with two pins, which are installed in conjunction with the pin holes on the outlet main plate 9 to reduce the thermal deformation of the outlet main plate during laser welding and ensure the installation flatness of the main plate, thereby meeting the airtightness requirements of the EGR cooler. The flange surface on the outlet side of the housing is provided with a large chamfer 22 of 10 mm, which provides space for the "elastic" deformation of the outlet main plate assembly and is conducive to further release of thermal stress.

[0053] The hot and cold shock test of EGR cooler is to test its ability to resist the thermal expansion stress damage caused by periodic heat load. The periodic heat load causes the parts (intake main plate, heat pipe, outlet main plate) to produce cyclic deformation, which may cause fatigue fracture of the cooler in severe cases. Fig.11 As shown, the change of exhaust gas temperature under different engine operating conditions causes irregular expansion and contraction deformation of the radiator pipe. Fig.14It is the test condition for hot and cold shock of EGR cooler, which is usually divided into hot shock stage (temperature is about 700-800℃, duration is 20-25s) and cold shock stage (temperature is about 100-130℃, duration is 20-25s). A single cycle includes hot shock and cold shock stages. In order to shorten the verification time, this condition is an accelerated verification condition, which is more stringent than the actual vehicle condition.

[0054] The optimal solution is determined by comparing the thermal shock life (i.e., the number of cycles when fatigue cracking occurs) of diaphragms 21 with different thicknesses. As shown in the following table, diaphragms with thicknesses of 0.6mm, 0.7mm, 0.8mm, 0.9mm and 2mm are selected for hot and cold shock tests. The test results show that the EGR cooler using a diaphragm with a thickness of 0.8mm has the best thermal durability.

[0055] Serial number Diaphragm thickness (mm) Thermal shock life (times) 1 2 12785 2 0.6 17920 3 0.7 18050 4 0.8 18300 5 0.9 18125

[0056] The above shows and describes the basic principles and main structural features of the present invention. The present invention is not limited to the above examples. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An exhaust gas recirculation cooler using a split air outlet main plate, comprising an air inlet chamber, an air inlet main plate, an air inlet sealing pad, a heat dissipation pipe group, a shell, an air outlet main plate, an air outlet sealing pad and an air outlet chamber, wherein the air inlet side of the shell is provided with an air inlet chamber, and the air outlet side is provided with an air outlet chamber; an air inlet main plate is provided between the air inlet chamber and the shell, and an air inlet sealing pad is provided between the air inlet main plate, the air inlet chamber and the shell; an air outlet main plate is provided between the air outlet chamber and the shell, and an air outlet sealing pad is provided between the air outlet main plate, the air outlet chamber and the shell; the heat dissipation pipe group is provided in the shell, and is connected to the air holes of the air inlet main plate and the air outlet main plate correspondingly; a water inlet is provided on the air inlet side of the shell, and a water outlet is provided on the air outlet side; the characteristics are: The main air outlet plate includes an insert and a diaphragm, the diaphragm is fixed between the shell and the air outlet chamber, and an insert mounting hole is provided in the middle, the insert mounting hole is vertically provided with a flange structure on the side away from the heat dissipation tube group installation, and the insert is fixedly arranged on the flange structure of the insert mounting hole; The thickness of the diaphragm is 0.8 mm, the height of the flange structure is 4.5 mm, and the thickness of the insert is 2 mm; the insert is fixedly mounted on the top of the flange structure, and the height difference with the top is not greater than 0.1 mm; the maximum assembly gap around the insert and the flange structure is 0.1 mm; The flange surface on the gas outlet side of the shell is provided with two pins which are installed in cooperation with the diaphragm; the flange surface on the gas outlet side of the shell is provided with a chamfer of 10 mm; The shell and outlet flange are made of aluminum, and the rest of the parts are made of stainless steel, which reduces the weight of the cooler while ensuring that the ambient temperature requirements are met; The 0.8mm thick diaphragm acts like a "spring", effectively compensating for the deformation caused by thermal expansion and contraction of the heat dissipation tube group and releasing thermal stress; The assembly position of the diaphragm and the insert adopts a flange structure, which effectively reduces the local torque deformation of the diaphragm, concentrates the deformation in the direction of thermal expansion of the heat dissipation tube group, and then releases the thermal expansion stress by the "elastic" deformation of the diaphragm, thereby reducing the risk of cracking of the weld or the main piece.

2. The exhaust gas recirculation cooler using a split-type air outlet main plate according to claim 1, characterized in that: The insert and the diaphragm are first pre-assembled, and the pre-assembly pull-off force is greater than 90N; and then fixed by laser welding.

3. The exhaust gas recirculation cooler using a split-type air outlet main plate according to claim 1, characterized in that: The air intake chamber adopts a double-flow exhaust gas inlet, and a baffle is cast between the double flow channels.

4. The exhaust gas recirculation cooler using a split-type outlet main plate according to claim 1, characterized in that: The water inlet is arranged at the lower part of the air inlet side of the shell, and the water outlet is arranged at the upper part of the air outlet side of the shell.

5. The exhaust gas recirculation cooler using a split-type air outlet main plate according to claim 1, characterized in that: The heat dissipation tubes of the heat dissipation tube group are pitted heat dissipation tubes.

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