EGR cooler and vehicle power system

Abstract

The invention belongs to the technical field of vehicles, and discloses an EGR cooler and a vehicle power system.The EGR cooler comprises a pre-cooler and a main cooler, before waste gas enters the main cooler, the waste gas firstly passes through a pre-cooling pipeline in the pre-cooler and exchanges heat with a cooling medium in a pre-cooling flow channel to be pre-cooled, then the waste gas enters the main cooling pipeline to be cooled, and then the waste gas enters the main cooling pipeline to be cooled; when high-temperature waste gas enters the pre-cooling pipeline, the pre-cooling pipeline is heated, due to the fact that the pre-cooler shell and the pre-cooling pipeline are integrally cast and formed, the structural strength between the pre-cooler shell and the pre-cooling pipeline is high, the pre-cooler shell and the pre-cooling pipeline cannot crack due to stress, in addition, the waste gas entering the main cooling pipeline is pre-cooled, stress generated at the connecting position of the main cooling pipeline is small, and the pre-cooling pipeline is not prone to cracking. And the joint of the main cooling pipeline can be prevented from cracking.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and particularly to an EGR cooler and a vehicle power system. Background Art

[0002] The Exhaust Gas Recirculation (EGR) system recirculates part of the exhaust gas back into the combustion chamber, absorbs heat and dilutes the oxygen concentration, reducing the combustion temperature to below 1300°C and suppressing the generation of nitrogen oxides. In some EGR systems, an EGR cooler is also provided to further reduce the temperature of the exhaust gas. The exhaust gas passage inside the EGR cooler usually consists of multiple heat exchange tubes, and multiple heat exchange tubes are all welded to the main board. The exhaust gas inside the heat exchange tubes can exchange heat with the external cooling medium, thereby cooling the exhaust gas. However, the exhaust temperature of the engine is very high, and the heat exchange tubes will be deformed by heat, resulting in an increase in stress. In severe cases, it may even cause the weld between the heat exchange tubes and the main board to crack.

[0003] In response to this, the prior art provides an EGR cooler which is provided with a main heat exchange part and a pre-cooling part at the same time. The pre-cooling part is located upstream of the main heat exchange part. The temperature of the exhaust gas pre-cooled by the pre-cooling part is relatively low, which can avoid excessive stress in the main heat exchange part. However, the problem is that the heat exchange tubes in the pre-cooling part are also connected to the main board in a welded form. The heat exchange tubes in the pre-cooling part directly contacting the high-temperature exhaust gas will also be deformed by heat, resulting in an increase in stress, and further causing the weld between the heat exchange tubes in the pre-cooling part and the main board to be prone to cracking. Summary of the Invention

[0004] According to one aspect of the present invention, the present invention provides an EGR cooler to solve the problem that the weld between the heat exchange tubes in the pre-cooling part and the main board in the prior art is prone to cracking.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] An EGR cooler, comprising:

[0007] A pre-cooler, comprising a pre-cooler housing and a pre-cooling pipeline integrally cast. The pre-cooling pipeline is arranged inside the pre-cooler housing, and a pre-cooling flow channel for the cooling medium to pass through is formed between the pre-cooler housing and the pre-cooling pipeline. The pre-cooling pipeline is for the exhaust gas to pass through, and the exhaust gas in the pre-cooling pipeline can exchange heat with the cooling medium in the pre-cooling flow channel;

[0008] A main cooler, having a main cooling flow channel for the cooling medium to pass through and a main cooling pipeline for the exhaust gas to pass through and located downstream of the pre-cooling pipeline. The exhaust gas in the main cooling pipeline can exchange heat with the cooling medium in the main cooling flow channel.

[0009] As a preferred solution for the EGR cooler, the pre-cooler is connected with a pre-cooler cooling medium inlet pipeline and a pre-cooler cooling medium outlet pipeline, and the cooling medium can enter the pre-cooling flow channel from the inner cavity of the pre-cooler cooling medium inlet pipeline and flow out through the inner cavity of the pre-cooler cooling medium outlet pipeline.

[0010] As a preferred solution for the EGR cooler, the pre-cooler housing, the pre-cooling pipeline, the pre-cooler cooling medium inlet pipeline and the pre-cooler cooling medium outlet pipeline are integrally cast.

[0011] As a preferred solution for the EGR cooler, the main cooler is connected with a main cooler cooling medium inlet pipeline and a main cooler cooling medium outlet pipeline, and the cooling medium can enter the main cooling flow channel from the inner cavity of the main cooler cooling medium inlet pipeline and flow out through the inner cavity of the main cooler cooling medium outlet pipeline;

[0012] The pre-cooler cooling medium inlet pipeline is connected to a cooling medium source, the pre-cooler cooling medium outlet pipeline is connected to the main cooler cooling medium inlet pipeline, and the main cooler cooling medium outlet pipeline is connected to a cooling medium collection structure; or, the main cooler cooling medium inlet pipeline is connected to a cooling medium source, the main cooler cooling medium outlet pipeline is connected to the pre-cooler cooling medium inlet pipeline, and the pre-cooler cooling medium outlet pipeline is connected to a cooling medium collection structure; or, the pre-cooler cooling medium inlet pipeline and the main cooler cooling medium inlet pipeline are simultaneously connected to a cooling medium source, and the pre-cooler cooling medium outlet pipeline and the main cooler cooling medium outlet pipeline are simultaneously connected to a cooling medium collection structure.

[0013] As a preferred solution for the EGR cooler, the pre-cooler is connected with a pre-cooler inlet flange for connecting an intake pipeline, and the pre-cooler housing, the pre-cooling pipeline and the pre-cooler inlet flange are integrally cast.

[0014] As a preferred solution for the EGR cooler, the pre-cooler is connected with a pre-cooler outlet flange, the main cooler is connected with a main cooler inlet flange, the pre-cooler outlet flange is fixedly connected to the main cooler inlet flange, and the pre-cooler housing, the pre-cooling pipeline and the pre-cooler outlet flange are integrally cast.

[0015] As a preferred solution for the EGR cooler, the main cooler includes a main cooler housing, the main cooling pipeline is arranged inside the main cooler housing, and a main cooling flow channel is formed between the main cooler housing and the main cooling pipeline; the pre-cooler housing and the main cooler housing are integrally cast.

[0016] As a preferred embodiment of the EGR cooler, a plurality of pre-cooling pipelines are provided, and the plurality of pre-cooling pipelines are arranged in a rectangular array.

[0017] As a preferred embodiment of the EGR cooler, the pre-cooling pipeline is strip-shaped or wavy.

[0018] According to another aspect of the present invention, a vehicle power system is provided, which includes the above EGR cooler, and further includes an engine and an EGR pipeline. The EGR pipeline is connected to the exhaust pipeline of the engine for the entry of exhaust gas and for conveying the exhaust gas to the intake pipeline of the engine. The EGR cooler is arranged in the EGR pipeline and is used for cooling the exhaust gas discharged from the exhaust pipeline of the engine.

[0019] The beneficial effects of the present invention are as follows:

[0020] The present invention provides an EGR cooler, which includes a pre-cooler and a main cooler. The pre-cooler includes a pre-cooler housing and pre-cooling pipelines integrally cast. The pre-cooling pipelines are arranged inside the pre-cooler housing, and a pre-cooling flow channel for the passage of a cooling medium is formed between the pre-cooler housing and the pre-cooling pipelines. The pre-cooling pipelines are for the passage of exhaust gas, and the exhaust gas in the pre-cooling pipelines can exchange heat with the cooling medium in the pre-cooling flow channel, so that before the exhaust gas enters the main cooler, it first passes through the pre-cooling pipelines in the pre-cooler and exchanges heat with the cooling medium in the pre-cooling flow channel for pre-cooling. The main cooler has a main cooling flow channel for the passage of a cooling medium and a main cooling pipeline for the passage of exhaust gas and located downstream of the pre-cooling pipelines. The exhaust gas in the main cooling pipeline can exchange heat with the cooling medium in the main cooling flow channel, so as to cool the exhaust gas in the main cooling pipeline. When the high-temperature exhaust gas enters the pre-cooling pipelines, the pre-cooling pipelines are heated. Since the pre-cooler housing and the pre-cooling pipelines are integrally cast, the structural strength between the pre-cooler housing and the pre-cooling pipelines is relatively high and will not crack due to stress. In addition, the exhaust gas entering the main cooling pipeline has been pre-cooled, and the stress generated at the connection of the main cooling pipeline is small, which can also avoid cracking at the connection of the main cooling pipeline.

[0021] The present invention also provides a vehicle power system, which includes the above EGR cooler, an engine, and an EGR pipeline. The EGR pipeline is connected to the exhaust pipeline of the engine for the entry of exhaust gas and is used to transport the exhaust gas to the intake pipeline of the engine. The EGR cooler is arranged in the EGR pipeline and is used to cool the exhaust gas discharged from the exhaust pipeline of the engine. In this EGR cooler, before the exhaust gas enters the main cooler, it first passes through the pre-cooling pipeline in the pre-cooler and exchanges heat with the cooling medium in the pre-cooling flow channel for pre-cooling. Subsequently, the exhaust gas enters the main cooling pipeline for cooling. When the high-temperature exhaust gas enters the pre-cooling pipeline, the pre-cooling pipeline is heated. Since the pre-cooler housing and the pre-cooling pipeline are integrally cast, the structural strength between the pre-cooler housing and the pre-cooling pipeline is relatively high and will not crack due to stress. In addition, the exhaust gas entering the main cooling pipeline has been pre-cooled, and the stress generated at the connection of the main cooling pipeline is relatively small, which can also avoid cracking at the connection of the main cooling pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of the EGR cooler in an embodiment of the present invention;

[0023] Figure 2 is a cross-sectional view of the pre-cooler in an embodiment of the present invention;

[0024] Figure 3 is a schematic structural diagram of the pre-cooler in an embodiment of the present invention;

[0025] Figure 4 is a schematic structural diagram of the main cooler in an embodiment of the present invention.

[0026] In the figure:

[0027] 1. Pre-cooler; 101. Pre-cooling flow channel; 11. Pre-cooler housing; 12. Pre-cooling pipeline; 13. Pre-cooler cooling medium inlet pipeline; 131. Pre-cooler cooling medium inlet flange; 14. Pre-cooler cooling medium outlet pipeline; 141. Pre-cooler cooling medium outlet flange; 15. Pre-cooler inlet flange; 151. First main board; 16. Pre-cooler outlet flange; 161. Second main board;

[0028] 2. Main cooler; 21. Main cooler housing; 22. Main cooling pipeline; 23. Main cooler cooling medium inlet pipeline; 24. Main cooler cooling medium outlet pipeline; 25. Main cooler inlet flange; 251. Third main board;

[0029] 3. Intake pipeline; 31. Intake pipeline connection flange; 32. Intake port;

[0030] 4. Exhaust pipeline; 41. Exhaust port. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. In addition, it should be noted that for the sake of convenience of description, only the parts related to the present invention are shown in the drawings, rather than all the structures.

[0032] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0033] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "above and to the right", and "above and to the left" of the second feature includes the first feature being directly above and diagonally above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "below and to the right", and "below and to the left" of the second feature includes the first feature being directly below and diagonally below the second feature, or merely indicating that the horizontal height of the first feature is lower than that of the second feature.

[0034] In the description of this embodiment, the orientation or positional relationship such as "above", "below", "left", and "right" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0035] The exhaust gas passage inside the EGR cooler is usually composed of multiple heat exchange tubes, and the multiple heat exchange tubes are all welded to the main board. The exhaust gas inside the heat exchange tubes can exchange heat with the external cooling medium, thereby cooling the exhaust gas. However, the exhaust gas temperature of the engine is very high, and the heat exchange tubes will be deformed by heat, resulting in an increase in stress. In severe cases, the welded joints between the heat exchange tubes and the main board may even crack. In response to this, the prior art provides an EGR cooler, which is provided with a main heat exchange part and a pre-cooling part at the same time. The pre-cooling part is located upstream of the main heat exchange part. The temperature of the exhaust gas pre-cooled by the pre-cooling part is relatively low, which can avoid excessive stress on the main heat exchange part. However, the problem is that the heat exchange tubes in the pre-cooling part are also connected to the main board in a welded form. The heat exchange tubes in the pre-cooling part that are directly in contact with the high-temperature exhaust gas will also be deformed by heat, resulting in an increase in stress, and then the welded joints between the heat exchange tubes in the pre-cooling part and the main board are prone to cracking.

[0036] In response to this, the present embodiment provides an EGR cooler to solve the problem that the welded joints between the heat exchange tubes in the pre-cooling part and the main board in the prior art are prone to cracking, and it can be used in the field of vehicle technology.

[0037] Referring to Figures 1 - 4 , the EGR cooler includes a pre-cooler 1 and a main cooler 2. The pre-cooler 1 includes a pre-cooler housing 11 and a pre-cooling pipeline 12 integrally cast. The pre-cooling pipeline 12 is arranged inside the pre-cooler housing 11, and a pre-cooling flow channel 101 for the cooling medium to pass through is formed between the pre-cooler housing 11 and the pre-cooling pipeline 12. The pre-cooling pipeline 12 is for the exhaust gas to pass through, and the exhaust gas in the pre-cooling pipeline 12 can exchange heat with the cooling medium in the pre-cooling flow channel 101, so that before the exhaust gas enters the main cooler 2, it first passes through the pre-cooling pipeline 12 in the pre-cooler 1 and exchanges heat with the cooling medium in the pre-cooling flow channel 101 for pre-cooling. The main cooler 2 has a main cooling flow channel for the cooling medium to pass through and a main cooling pipeline 22 for the exhaust gas to pass through and located downstream of the pre-cooling pipeline 12. The exhaust gas in the main cooling pipeline 22 can exchange heat with the cooling medium in the main cooling flow channel, so as to cool the exhaust gas in the main cooling pipeline 22. When the high-temperature exhaust gas enters the pre-cooling pipeline 12, the pre-cooling pipeline 12 is heated. Since the pre-cooler housing 11 and the pre-cooling pipeline 12 are integrally cast, the structural strength between the pre-cooler housing 11 and the pre-cooling pipeline 12 is relatively high and will not crack due to stress. In addition, the exhaust gas entering the main cooling pipeline 22 has been pre-cooled, and the deformation amount of the main cooling pipeline 22 caused by heat is small, and the stress generated at the connection is small, which can also avoid cracking at the connection of the main cooling pipeline 22.

[0038] Continue to refer to Figures 1 - 4, the pre-cooler 1 is connected with a pre-cooler cooling medium inlet pipeline 13 and a pre-cooler cooling medium outlet pipeline 14. The cooling medium can enter the pre-cooling flow channel 101 from the inner cavity of the pre-cooler cooling medium inlet pipeline 13 and flow out through the inner cavity of the pre-cooler cooling medium outlet pipeline 14, so that the cooling medium flows in the pre-cooling flow channel 101 and completes heat exchange during the flowing process.

[0039] Continue to refer to Figures 1 - 4 , the pre-cooler housing 11, the pre-cooling pipeline 12, the pre-cooler cooling medium inlet pipeline 13 and the pre-cooler cooling medium outlet pipeline 14 are integrally cast, so as to further improve the overall structural strength of the pre-cooler 1 and facilitate production and processing. Optionally, in order to facilitate the connection between the pre-cooler cooling medium inlet pipeline 13 and the external pipeline, a pre-cooler cooling medium inlet flange 131 is further provided at one end of the pre-cooler cooling medium inlet pipeline 13 away from the pre-cooler housing 11; in addition, in order to facilitate the connection between the pre-cooler cooling medium outlet pipeline 14 and the external pipeline, a pre-cooler cooling medium outlet flange 141 is further provided at one end of the pre-cooler cooling medium outlet pipeline 14 away from the pre-cooler housing 11. Further optionally, the pre-cooler cooling medium inlet flange 131 and the pre-cooler cooling medium outlet flange 141 are also integrally cast with the above structure.

[0040] Continue to refer to Figures 1 - 4 , the main cooler 2 is connected with a main cooler cooling medium inlet pipeline 23 and a main cooler cooling medium outlet pipeline 24. The cooling medium can enter the main cooling flow channel from the inner cavity of the main cooler cooling medium inlet pipeline 23 and flow out through the inner cavity of the main cooler cooling medium outlet pipeline 24, so that the cooling medium can flow in the main cooling flow channel. The connection modes among the pre-cooler cooling medium inlet pipeline 13, the pre-cooler cooling medium outlet pipeline 14, the main cooler cooling medium inlet pipeline 23 and the main cooler cooling medium outlet pipeline 24 are as follows:

[0041] The first one is that the pre-cooler cooling medium inlet pipeline 13 is connected with a cooling medium source, the pre-cooler cooling medium outlet pipeline 14 is connected with the main cooler cooling medium inlet pipeline 23, and the main cooler cooling medium outlet pipeline 24 is connected with a cooling medium collection structure. Among them, both the cooling medium source and the cooling medium collection structure are components in the engine cooling system. In this scheme, the cooling medium first flows through the pre-cooling flow channel 101, exchanges heat with the exhaust gas in the pre-cooling pipeline 12, and then the cooling medium flows into the main cooling flow channel and exchanges heat with the exhaust gas in the main cooling pipeline 22, that is, first cools the exhaust gas in the pre-cooler 1 and then cools the exhaust gas in the main cooler 2.

[0042] The second is that the main cooler cooling medium inlet pipeline 23 is connected to the cooling medium source, the main cooler cooling medium outlet pipeline 24 is connected to the pre-cooler cooling medium inlet pipeline 13, and the pre-cooler cooling medium outlet pipeline 14 is connected to the cooling medium collection structure. In this solution, the cooling medium first flows through the main cooling channel and exchanges heat with the exhaust gas in the main cooling pipeline 22, and then the cooling medium flows into the pre-cooling channel 101 and exchanges heat with the exhaust gas in the pre-cooling pipeline 12, that is, the exhaust gas in the main cooler 2 is cooled first, and then the exhaust gas in the pre-cooler 1 is cooled.

[0043] The third is that the pre-cooler cooling medium inlet pipeline 13 and the main cooler cooling medium inlet pipeline 23 are simultaneously connected to the cooling medium source, and the pre-cooler cooling medium outlet pipeline 14 and the main cooler cooling medium outlet pipeline 24 are simultaneously connected to the cooling medium collection structure. In this solution, the cooling medium flows to the pre-cooling channel 101 and the main cooling channel simultaneously. The cooling medium located in the pre-cooling channel 101 exchanges heat with the exhaust gas in the pre-cooling pipeline 12, and the cooling medium located in the main cooling channel exchanges heat with the exhaust gas in the main cooling pipeline 22, that is, the exhaust gas in the pre-cooler 1 and the main cooler 2 are cooled simultaneously.

[0044] Continue to refer to Figures 1 - 4 , the pre-cooler 1 is connected with a pre-cooler inlet flange 15, and the pre-cooler inlet flange 15 is used to connect the intake pipeline 3. Specifically, the intake pipeline 3 is provided with an intake pipeline connection flange 31, and the pre-cooler inlet flange 15 is connected to the intake pipeline connection flange 31. The intake port 32 of the intake pipeline 3 is used to connect to the exhaust pipeline of the engine, and is used to introduce part of the engine exhaust gas into the EGR cooler. The pre-cooler housing 11, the pre-cooling pipeline 12 and the pre-cooler inlet flange 15 are integrally cast, so as to further improve the overall structural strength of the pre-cooler 1, avoid structural damage caused by excessive stress, and facilitate production and processing. Optionally, along the flow direction of the exhaust gas, the cross-sectional area of the intake pipeline 3 gradually increases, so that the flow velocity of the exhaust gas gradually decreases during the flow in the intake pipeline 3, thereby improving the heat exchange effect.

[0045] Continue to refer to Figures 1 - 4 , the pre-cooler 1 is connected with a pre-cooler outlet flange 16, the main cooler 2 is connected with a main cooler inlet flange 25, the pre-cooler outlet flange 16 is fixedly connected to the main cooler inlet flange 25, and the pre-cooler housing 11, the pre-cooling pipeline 12 and the pre-cooler outlet flange 16 are integrally cast, so as to further improve the overall structural strength of the pre-cooler 1, avoid structural damage caused by excessive stress, and facilitate production and processing. Optionally, one end of the main cooler 2 away from the pre-cooler 1 is connected with an exhaust pipeline 4, and the exhaust port 41 of the exhaust pipeline 4 is used to discharge the exhaust gas cooled by the EGR cooler. After the exhaust gas passes through the exhaust port 41, it will be transported to the engine intake pipe.

[0046] Optionally, the pre-cooler housing 11 includes a pre-cooler housing side wall, and a first main board 151 and a second main board 161 disposed at both ends of the pre-cooler housing side wall. The main cooler 2 includes a main cooler housing 21. The main cooling pipeline 22 is disposed inside the main cooler housing 21, and a main cooling flow channel is formed between the main cooler housing 21 and the main cooling pipeline 22. The main cooler housing 21 includes a main cooler housing side wall, and a third main board 251 and a fourth main board disposed at both ends of the main cooler housing side wall. The first main board 151 is used to block the inner cavity of the intake pipeline 31 and the pre-cooling flow channel 101. Both the second main board 161 and the third main board 251 are used to block the pre-cooling flow channel 101 and the main cooling flow channel. The fourth main board is used to seal one end of the main cooling flow channel close to the exhaust pipeline 4. With such a setting, the pre-cooling flow channel 101 is separated from both the inner cavity of the intake pipeline 31 and the main cooling flow channel at the same time. The cooling medium can only flow in from the pre-cooler cooling medium inlet pipeline 13 and flow out from the pre-cooler cooling medium outlet pipeline 14. In addition, the main cooling flow channel can also be separated from the pre-cooling flow channel 101 and the external space. The cooling medium can only flow in from the main cooler cooling medium inlet pipeline 23 and flow out from the main cooler cooling medium outlet pipeline 24.

[0047] In this embodiment, the pre-cooler outlet flange 16 is fixedly connected to the main cooler inlet flange 25, thereby fixedly connecting the pre-cooler 1 and the main cooler 2. In other embodiments, the pre-cooler housing 11 and the main cooler housing 21 are integrally cast, thereby enhancing the connection structure strength between the pre-cooler 1 and the main cooler 2.

[0048] Continue to refer to Figures 1 - 4 , a plurality of pre-cooling pipelines 12 are provided, and the plurality of pre-cooling pipelines 12 are arranged in a rectangular array. The cooling medium can flow between the plurality of pre-cooling pipelines 12 arranged in a rectangular array and exchange heat with the plurality of pre-cooling pipelines 12, thereby enhancing the heat exchange effect.

[0049] Optionally, a plurality of main cooling pipelines 22 are also provided, and the plurality of main cooling pipelines 22 are arranged in a rectangular array. In addition, the plurality of pre-cooling pipelines 12 are connected to the plurality of main cooling pipelines 22 in a one-to-one correspondence. The cooling medium can flow between the plurality of main cooling pipelines 22 arranged in a rectangular array and exchange heat with the plurality of main cooling pipelines 22, thereby enhancing the heat exchange effect. Further, in order to enhance the heat exchange effect, the main cooling pipeline 22 is provided with heat exchange fins.

[0050] Continue to refer to Figures 1 - 4 , the pre-cooling pipeline 12 is strip-shaped or wavy to increase the heat exchange area and enhance the heat exchange efficiency. Optionally, the main cooling pipeline 22 is also strip-shaped or wavy.

[0051] This embodiment also provides a vehicle power system, which can be applied to a vehicle. The vehicle power system includes the above EGR cooler, an engine, and an EGR pipeline. The EGR pipeline is connected to the exhaust pipeline of the engine for the entry of exhaust gas and for delivering the exhaust gas to the intake pipeline of the engine. The EGR cooler is disposed in the EGR pipeline and is used to cool the exhaust gas discharged from the exhaust pipeline of the engine. In this EGR cooler, before the exhaust gas enters the main cooler 2, it first passes through the pre-cooling pipeline 12 in the pre-cooler 1 and exchanges heat with the cooling medium in the pre-cooling flow channel 101 for pre-cooling, and then the exhaust gas enters the main cooling pipeline 22 for cooling. When the high-temperature exhaust gas enters the pre-cooling pipeline 12, the pre-cooling pipeline 12 is heated. Since the pre-cooler housing 11 and the pre-cooling pipeline 12 are integrally cast, the structural strength between the pre-cooler housing 11 and the pre-cooling pipeline 12 is relatively high and will not crack due to stress. In addition, the exhaust gas entering the main cooling pipeline 22 has been pre-cooled, and the stress generated at the connection of the main cooling pipeline 22 is small, which can also avoid cracking at the connection of the main cooling pipeline 22.

[0052] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments, and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. EGR cooler, characterized in that: include: A precooler (1) comprises a precooler shell (11) and a precooling pipeline (12) which are integrally cast, wherein the precooling pipeline (12) is arranged inside the precooler shell (11), and a precooling channel (101) for a cooling medium to pass through is formed between the precooler shell (11) and the precooling pipeline (12), the precooling pipeline (12) is used for exhaust gas to pass through, and the exhaust gas in the precooling pipeline (12) can exchange heat with the cooling medium in the precooling channel (101); The main cooler (2) comprises a main cooling channel for a cooling medium to pass through and a main cooling pipeline (22) for exhaust gas to pass through and located downstream of the pre-cooling pipeline (12); the exhaust gas in the main cooling pipeline (22) can exchange heat with the cooling medium in the main cooling channel.

2. The EGR cooler according to claim 1, characterized in that: The precooler (1) is connected to a precooler cooling medium inlet pipeline (13) and a precooler cooling medium outlet pipeline (14); the cooling medium can enter the precooling channel (101) from the inner cavity of the precooler cooling medium inlet pipeline (13) and flow out through the inner cavity of the precooler cooling medium outlet pipeline (14).

3. The EGR cooler according to claim 2, characterized in that: The precooler shell (11), the precooling pipeline (12), the precooler cooling medium inlet pipeline (13) and the precooler cooling medium outlet pipeline (14) are integrally cast.

4. The EGR cooler according to claim 2, characterized in that: The main cooler (2) is connected to a main cooler cooling medium inlet pipeline (23) and a main cooler cooling medium outlet pipeline (24), and the cooling medium can enter the main cooling channel from the inner cavity of the main cooler cooling medium inlet pipeline (23) and flow out through the inner cavity of the main cooler cooling medium outlet pipeline (24); The precooler cooling medium inlet pipeline (13) is connected to a cooling medium source, the precooler cooling medium outlet pipeline (14) is connected to the main cooler cooling medium inlet pipeline (23), and the main cooler cooling medium outlet pipeline (24) is connected to a cooling medium collecting structure; or, the main cooler cooling medium inlet pipeline (23) is connected to a cooling medium source, the main cooler cooling medium outlet pipeline (24) is connected to the precooler cooling medium inlet pipeline (13), and the precooler cooling medium outlet pipeline (14) is connected to a cooling medium collecting structure; or, the precooler cooling medium inlet pipeline (13) and the main cooler cooling medium inlet pipeline (23) are simultaneously connected to a cooling medium source, and the precooler cooling medium outlet pipeline (14) and the main cooler cooling medium outlet pipeline (24) are simultaneously connected to a cooling medium collecting structure.

5. The EGR cooler according to any one of claims 1 to 4, characterized in that: The precooler (1) is connected to a precooler inlet flange (15), and the precooler inlet flange (15) is used to connect to an air intake pipeline (3). The precooler housing (11), the precooling pipeline (12) and the precooler inlet flange (15) are integrally cast.

6. The EGR cooler according to any one of claims 1 to 4, characterized in that: The precooler (1) is connected to a precooler outlet flange (16), the main cooler (2) is connected to a main cooler inlet flange (25), the precooler outlet flange (16) is fixedly connected to the main cooler inlet flange (25), and the precooler housing (11), the precooling pipeline (12) and the precooler outlet flange (16) are integrally cast.

7. The EGR cooler according to any one of claims 1 to 4, characterized in that: The main cooler (2) comprises a main cooler shell (21), the main cooling pipeline (22) is arranged inside the main cooler shell (21), and the main cooling flow channel is formed between the main cooler shell (21) and the main cooling pipeline (22); the precooler shell (11) and the main cooler shell (21) are integrally cast.

8. The EGR cooler according to any one of claims 1 to 4, characterized in that: A plurality of the precooling pipelines (12) are provided, and the plurality of the precooling pipelines (12) are arranged in a rectangular array.

9. The EGR cooler according to any one of claims 1 to 4, characterized in that: The precooling pipeline (12) is in the shape of a long strip or a wave.

10. A vehicle power system, characterized in that: It includes the EGR cooler as described in any one of claims 1 to 9, and also includes an engine and an EGR pipeline, the EGR pipeline is connected to the exhaust pipeline of the engine for exhaust gas to enter and for transporting the exhaust gas to the intake pipeline of the engine, the EGR cooler is arranged in the EGR pipeline and is used to cool the exhaust gas discharged from the exhaust pipeline of the engine.

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