EGR cooler front-end precooler

Abstract

A precooler at the front end of an EGR cooler comprises a precooler body and the EGR cooler, the precooler body comprises a first connector, a second connector, an air pipe assembly and a cooling liquid shell, the air pipe assembly comprises a first air inlet pipe and a second air inlet pipe, and the first air inlet pipe and / or the second air inlet pipe adopt / adopts an air inlet pipe unit. The air inlet pipe unit comprises a pipe inner wall, a pipe outer wall and an airflow cavity channel, an isolation cavity is formed between the pipe inner wall and the pipe outer wall, and a corrugated pipe part is arranged in the middle of the pipe outer wall; the cooling liquid shell comprises a liquid inlet and a liquid outlet. The cooling liquid shell comprises a first cooling liquid cavity. In order to solve the problem that an existing EGR cooler is prone to being affected by thermal stress generated by thermal expansion and cold contraction, and consequently the thermal fatigue resistance is poor, the corrugated pipe with the interval part is adopted to release the expansion amount, the cooling liquid circulation structure is arranged outside the corrugated pipe to cool gas in the corrugated pipe, and the cooling effect of the EGR cooler is improved; the gas inlet pipe is of a double-layer structure and is used for installing welding allowance and preventing gas leakage.

Description

Technical Field

[0001] This invention belongs to the technical field of motor vehicle exhaust gas treatment devices, specifically relating to a pre-cooler at the front end of an EGR cooler. Background Technology

[0002] The EGR cooler is a core component of the automotive engine exhaust gas recirculation (EGR) system and is part of the exhaust gas treatment system. It is mainly used to control the emission of nitrogen oxides in the exhaust gas of internal combustion engines. It reduces the temperature and pressure of the combustion chamber by cooling the recirculated exhaust gas, thereby achieving environmental compliance.

[0003] In the operating environment of a gas engine, the inlet temperature of an EGR cooler is typically around 780℃. When this high-temperature gas is introduced into the EGR cooler for cooling, the flat tubes inside the EGR cooler are easily subjected to thermal stress caused by thermal expansion and contraction, which affects the thermal fatigue resistance of the EGR cooler and its cooling effect.

[0004] Therefore, a pre-cooling structure needs to be added to the front end of the EGR cooler to reduce the intake air temperature at the EGR cooler inlet to 680~700℃, thereby reducing the temperature of the main intake fins, reducing the thermal stress of the cooler assembly, and effectively improving the reliability of the product. Summary of the Invention

[0005] This invention addresses the problem that the flat tubes inside existing automotive EGR coolers are easily affected by thermal stress caused by thermal expansion and contraction, resulting in poor thermal fatigue resistance. It employs a corrugated tube with spacers to release the expansion, and a coolant circulation structure is arranged outside the corrugated tube to cool the gas inside, thereby reducing the intake air temperature at the EGR cooler inlet and improving the cooling effect of the EGR cooler. The intake pipe has a double-layer structure, which can be used to accommodate welding allowances and prevent gas leakage.

[0006] The technical problem solved by this invention can be achieved by the following technical solution: an EGR cooler front-end precooler, comprising a precooler body and an EGR cooler, the precooler body comprising a first connector at the front end, a second connector at the rear end for connecting to the EGR cooler, an air pipe assembly and a coolant housing located between the first connector and the second connector, the air pipe assembly comprising a first air inlet pipe and a second air inlet pipe, the first air inlet pipe and / or the second air inlet pipe employing an air inlet pipe unit, the air inlet pipe unit comprising an inner wall and an outer wall, the two ends of the inner wall being respectively fitted with the first connector and the second connector to form an airflow channel, an isolation cavity being provided between the inner wall and the outer wall, and a corrugated section being provided in the middle of the outer wall; the coolant housing comprising an inlet and an outlet, the two ends of the coolant housing being respectively fitted with the first connector and the second connector to form a first coolant cavity.

[0007] There is a certain distance between the first intake pipe and the second intake pipe, and a second coolant chamber is formed between the first intake pipe and the second intake pipe. The second coolant chamber is connected to the first coolant chamber.

[0008] When both the first and second intake pipes use intake pipe units, the bellows section of the first intake pipe and the bellows section of the second intake pipe are offset.

[0009] A single corrugated section includes 3 to 8 corrugated units. Several corrugated units are arranged at uniform intervals along the axial direction of the outer wall of the pipe. The corrugated units protrude outward in the radial direction of the outer wall of the pipe, and a spacer is formed between two adjacent corrugated units.

[0010] The first connector includes a first air inlet and a second air inlet, and the second connector includes a first air outlet and a second air outlet. The first air inlet and the first air outlet are respectively connected to both ends of the first air inlet pipe, and the second air inlet and the second air outlet are respectively connected to both ends of the second air inlet pipe.

[0011] When both the first and second intake pipes use intake pipe units, the first connector also includes two first connecting parts, and the second connector also includes two second connecting parts. The first connecting parts and the second connecting parts are respectively installed at both ends of the isolation cavity. A single first connecting part is installed in conjunction with the inner wall and outer wall of a single intake pipe unit, and a single second connecting part is installed in conjunction with the inner wall and outer wall of a single intake pipe unit.

[0012] The first connecting part is welded to the inner wall and the outer wall of the pipe, and the second connecting part is welded to the inner wall and the outer wall of the pipe.

[0013] Compared with the prior art, the present invention has the following beneficial effects: Addressing the problem that the flat tubes inside existing motor vehicle EGR coolers are easily affected by thermal stress caused by thermal expansion and contraction, resulting in poor thermal fatigue resistance, the present invention employs a corrugated tube with spacers to release the expansion. A coolant circulation structure is arranged outside the corrugated tube to cool the gas inside the corrugated tube, thereby reducing the intake air temperature at the EGR cooler inlet and improving the cooling effect of the EGR cooler. The intake pipe has a double-layer structure, which can be used to install welding allowance and prevent gas leakage. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the precooler body; Figure 2 This is a cross-section of the precooler body. Figure 1 ; Figure 3 This is a cross-section of the precooler body. Figure 2 ; Figure 4 This is a magnified view of a section of the bellows; Figure 5 This is a schematic diagram of the structure of the present invention.

[0015] In the diagram: 1-First connector, 11-First air inlet, 12-Second air inlet, 13-First connecting part, 2-Second connector, 21-First air outlet, 22-Second air outlet, 23-Second connecting part, 3-Air pipe assembly, 30-Air inlet pipe unit, 301-Inner wall of pipe, 302-Outer wall of pipe, 303-Airflow cavity, 304-Isolation cavity, 305-Bellow section, 3051-Bellow section, 3052-Separation section, 31-First air inlet pipe, 32-Second air inlet pipe, 4-Coolant housing, 41-Inlet, 42-Outlet, 43-First coolant chamber, 44-Second coolant chamber, 5-EGR cooler. Detailed Implementation

[0016] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations.

[0017] In the description of this invention, it should be understood that the terms "one end", "the other end", "outer side", "upper", "inner side", "horizontal", "coaxial", "center", "end", "length", "outer end", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0018] Combined with appendix Figures 1 to 5As shown, this embodiment discloses an EGR cooler front-end precooler, including a precooler body and an EGR cooler 5. The precooler body includes a first connector 1 at the front end, a second connector 2 at the rear end for connecting to the EGR cooler, an air pipe assembly 3 and a coolant housing 4 located between the first connector 1 and the second connector 2. The first connector 1 is used to connect to the engine exhaust pipe. The first connector 1 and the second connector 2 are preferably flange connectors. The air pipe assembly 3 includes a first intake pipe 31 and a second intake pipe 32. The first intake pipe 31 and the second intake pipe 32 are arranged in parallel in the coolant housing 4. The first intake pipe 31 and / or the second intake pipe 32 are intake pipe units 30. Preferably, in this embodiment, the first intake pipe 31 and the second intake pipe 32 are arranged in parallel in the coolant housing 4. The intake pipe 32 adopts an intake pipe unit 30. The intake pipe unit 30 includes an inner wall 301 and an outer wall 302. The two ends of the inner wall 301 are respectively installed with the first connector 1 and the second connector 2 to form an airflow cavity 303. An isolation cavity 304 is provided between the inner wall 301 and the outer wall 302. A corrugated pipe section 305 is provided at any position in the middle of the outer wall 302. The coolant housing 4 includes an inlet 41 and an outlet 42. Preferably, in this embodiment, the inlet 41 and the outlet 42 are located on the same side of the coolant housing 4. In other embodiments, they can also be located on opposite sides of the coolant housing 4. The two ends of the coolant housing 4 are respectively installed with the first connector 1 and the second connector 2 to form a first coolant cavity 43.

[0019] In conjunction with the above installation structure, the bellows section 305 is used to release thermal expansion allowance, thereby preventing the intake pipe unit 30 from cracking due to thermal expansion and contraction caused by the temperature difference between the inside and outside; the inner wall 301 is used to protect the bellows section 305 of the outer wall 302 of the pipe, preventing the high-temperature airflow in the airflow cavity 303 from directly impacting the bellows section 305; the isolation cavity 304 is installed in conjunction with the first connector 1 and the second connector 2 to install welding allowance, and forms a closed cavity. If the inner wall 301 of the pipe is damaged, the gas in the airflow cavity 303 will enter the isolation cavity 304, thereby improving the reliability and safety of the product.

[0020] In this embodiment, the bellows portion 305 of the first intake pipe 31 and the bellows portion 305 of the second intake pipe 32 are staggered. There is a certain distance between the first intake pipe 31 and the second intake pipe 32, and a second coolant chamber 44 is formed between the first intake pipe 31 and the second intake pipe 32. The second coolant chamber 44 is interconnected with the first coolant chamber 43 to increase the contact area between the first intake pipe 31 and the second intake pipe 32 and the coolant. At the same time, it is also used to prevent the staggered bellows portion 305 from interfering with the other intake pipe unit.

[0021] In conjunction with the above, a single corrugated section 305 includes 3 to 8 corrugated units 3051. Preferably, in this embodiment, the number of corrugated units 3051 in a single corrugated section 305 is 5. The corrugated units 3051 are arranged at uniform intervals along the axial direction of the outer wall 302 of the tube. The corrugated units 3051 protrude outward in the radial direction of the outer wall 302 of the tube. An interval 3052 is formed between two adjacent corrugated units 3051 to release thermal expansion margin.

[0022] In combination with the above, the first connector 1 includes a first air inlet 11 and a second air inlet 12, and the second connector 2 includes a first air outlet 21 and a second air outlet 22. The first air inlet 11 and the first air outlet 21 are respectively connected to both ends of the first air inlet pipe 31, and the second air inlet 12 and the second air outlet 22 are respectively connected to both ends of the second air inlet pipe 32.

[0023] In conjunction with the above, in this embodiment, the first connector 1 further includes two first connecting parts 13, and the second connector 2 further includes two second connecting parts 23. The first connecting parts 13 and the second connecting parts 23 are respectively installed at both ends of the isolation cavity 304. A single first connecting part 13 is installed in conjunction with the inner wall 301 and the outer wall 302 of a single air intake pipe unit 30, and a single second connecting part 23 is installed in conjunction with the inner wall 301 and the outer wall 302 of a single air intake pipe unit 30. Preferably, the first connecting part 13 is welded to the inner wall 301 and the outer wall 302, and the second connecting part 23 is welded to the inner wall 301 and the outer wall 302. The isolation cavity 304 is also used to install welding allowance.

[0024] This invention addresses the problem that the flat tubes inside existing automotive EGR coolers are easily affected by thermal stress caused by thermal expansion and contraction, resulting in poor thermal fatigue resistance. It employs a corrugated tube with spacers to release the expansion, and a coolant circulation structure is arranged outside the corrugated tube to cool the gas inside, thereby reducing the intake air temperature at the EGR cooler inlet and improving the cooling effect of the EGR cooler. The intake pipe has a double-layer structure, which can be used to accommodate welding allowances and prevent gas leakage.

[0025] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, equivalent changes, or alterations made to the above embodiments based on the technical principles of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. An EGR cooler front-end precooler, comprising a precooler body and an EGR cooler (5), characterized in that: The precooler body includes a first connector (1) at the front end, a second connector (2) at the rear end for connecting to the EGR cooler, a pipe assembly (3) between the first connector (1) and the second connector (2), and a coolant housing (4). The pipe assembly (3) includes a first inlet pipe (31) and a second inlet pipe (32). The first inlet pipe (31) and / or the second inlet pipe (32) adopt an inlet pipe unit (30). The inlet pipe unit (30) includes an inner wall (301) and an outer wall (302). 2) The inner wall (301) of the pipe is installed with the first connector (1) and the second connector (2) at both ends to form an airflow cavity (303). An isolation cavity (304) is provided between the inner wall (301) and the outer wall (302). A corrugated pipe section (305) is provided in the middle of the outer wall (302). The coolant housing (4) includes an inlet (41) and an outlet (42). The coolant housing (4) is installed with the first connector (1) and the second connector (2) at both ends to form a first coolant cavity (43).

2. The precooler at the front end of an EGR cooler according to claim 1, characterized in that: There is a certain distance between the first air intake pipe (31) and the second air intake pipe (32), and a second coolant chamber (44) is formed between the first air intake pipe (31) and the second air intake pipe (32). The second coolant chamber (44) is connected to the first coolant chamber (43).

3. The precooler at the front end of an EGR cooler according to claim 1, characterized in that: When both the first intake pipe (31) and the second intake pipe (32) adopt an intake pipe unit (30), the corrugated part (305) of the first intake pipe (31) and the corrugated part (305) of the second intake pipe (32) are misaligned.

4. The pre-cooler for an EGR cooler according to claim 3, characterized in that: Each of the corrugated sections (305) includes 3 to 8 corrugated units (3051), and the corrugated units (3051) are arranged at uniform intervals along the axial direction of the outer wall (302) of the pipe. The corrugated units (3051) protrude outward in the radial direction of the outer wall (302), and a spacer (3052) is formed between two adjacent corrugated units (3051).

5. An EGR cooler front-end precooler according to any one of claims 1 to 4, characterized in that: The first connector (1) includes a first air inlet (11) and a second air inlet (12), and the second connector (2) includes a first air outlet (21) and a second air outlet (22). The first air inlet (11) and the first air outlet (21) are respectively connected to both ends of the first air inlet pipe (31), and the second air inlet (12) and the second air outlet (22) are respectively connected to both ends of the second air inlet pipe (32).

6. The pre-cooler for an EGR cooler according to claim 5, characterized in that: When both the first intake pipe (31) and the second intake pipe (32) adopt intake pipe unit (30), the first connector (1) further includes two first connecting parts (13), and the second connector (2) further includes two second connecting parts (23). The first connecting parts (13) and the second connecting parts (23) are respectively installed at both ends of the isolation cavity (304). A single first connecting part (13) is installed in conjunction with the inner wall (301) and outer wall (302) of a single intake pipe unit (30), and a single second connecting part (23) is installed in conjunction with the inner wall (301) and outer wall (302) of a single intake pipe unit (30).

7. The precooler at the front end of an EGR cooler according to claim 6, characterized in that: The first connecting part (13) is welded to the inner wall (301) and the outer wall (302) of the pipe, and the second connecting part (23) is welded to the inner wall (301) and the outer wall (302) of the pipe.

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