WO2009044947A1

WO2009044947A1 - Exhaust gas recirculation cooler

Info

Publication number: WO2009044947A1
Application number: PCT/KR2007/004888
Authority: WO
Inventors: Tae Jin Kim; Yong Kuk Cho
Original assignee: Korens Co., Ltd.
Priority date: 2007-10-02
Filing date: 2007-10-08
Publication date: 2009-04-09
Also published as: KR100823654B1

Abstract

Provided is an exhaust gas recirculation (EGR) cooler for recirculating an exhaust gas from an exhaust manifold to an intake manifold of an engine. The EGR cooler includes a plurality of tubes for enabling an exhaust gas to pass, a coolant path between tubes for enabling a coolant to pass, and a coolant inlet and a coolant outlet communicating with the coolant path. The EGR cooler also includes a flange disposed at one end of the tube and having an exhaust gas inlet opening and an exhaust gas outlet opening, and a closing cap disposed at the other end of the tube. The exhaust gas inlet opening and the exhaust gas outlet opening are unequally partitioned by a dividing bar, and the exhaust gas inlet opening has a larger area than the exhaust gas outlet opening.

Description

EXHAUST GAS RECIRCULATION COOLER

Technical Field

[1] The present invention relates to an exhaust gas recirculation (EGR) cooler for re- circulating an exhaust gas from an exhaust manifold to an intake manifold of an engine and, more particularly, to an EGR cooler for cooling an exhaust gas using coolant. Background Art

[2] In general, an exhaust gas recirculation (EGR) is a system for reducing NOx by re- circulating a portion of an exhaust gas back to an intake system so as to increase the CO2 concentration in the inhaled air and decrease the temperature in a combustion chamber.

[3] At first, a NO generation mechanism will be described in detail. Air is composed of about 79% of nitrogen, 21% of oxygen, and a small amount of other elements. The nitrogen does not react with the oxygen at normal temperature. However, the nitrogen reacts with the oxygen at high temperature, for example, about 1450 ⁰C. As a result, thermal NO is created. A diesel engine is a compression ignition engine, in which the fuel ignites as it is injected into the engine. As the material quality of a cylinder has been advanced, the compression ratio thereof has increased. Accordingly, the temperature of the combustion chamber has also increased. Although the increase of the combustion temperature improves thermodynamic engine efficiency, the large amount of nitrous oxide is generated due to high temperature. The nitrous oxide, major noxious substance that destroys earth environment, causes acid rain, photochemical smog, and respiratory organ troubles. [4] In order to reduce NO , the EGR reduces the highest temperature in a combustion chamber by recirculating an inert gas such as steam and carbon dioxide, firstly. Secondly, the EGR prevents a nitrous oxide generation atmosphere which is caused by lean burn. Thirdly, the EGR delays ignition timing and reduces the highest temperature and pressure of a combustion chamber by inserting a high specific heat cooling inert gas. [5] Some studies have reported that the fundamental cause of the NOx reduction mechanism of the EGR in a diesel engine is the reduction of oxygen concentration unlike a gasoline engine. On the contrary, the other studies have reported that the fundamental cause of the NOx reduction mechanism of the EGR in a diesel engine is the reduction of flame temperature. Lately, it is reported that the contribution levels of the oxygen concentration and the flame temperature to the NOx reduction are about the same. [6] An EGR is one of methods for reducing NOx without particulate matter (PM) increased or without fuel efficiency decreased. As the regulations for controlling a diesel engine's an exhaust gas becomes strict, the EGR having an EGR cooler has been widely used. That is, the great effect of reducing NOx can be obtained with comparative low investment by installing a cooler using engine coolant.

[7] The EGR cooler must be made of thermal resistant material because the EGR cooler cools down an exhaust gas from about 700⁰C to about 15O⁰C to 200⁰C. Also, it is required to design the EGR cooler compactly because the EGR cooler must be installed in a vehicle. In order to apply the proper amount of exhaust gas recirculation, pressure drop must be minimized. The exhaust gas is condensed during heat exchange, and condensation water is generated therefrom. Due to sulfur component, the condensation water often includes sulphuric acid. The sulphuric acid may easily corrode the EGR cooler. Therefore, the EGR cooler must be made of anticorrosive material. Since a predetermined level of a mechanical load is applied by the pulsative effect of the exhaust gas, the EGR cooler must have a proper level of mechanical strength. Furthermore, the counterplan for fouling is required because the particulate matter (PM) of the exhaust gas may block a pipe.

[8] As shown in Fig. 1, the exhaust gas recirculation (EGR) 1 reduces NOx by re- circulating a portion of an exhaust gas exhausted through an exhaust manifold 3 to an intake manifold 2. An EGR cooler 4 is disposed at the middle of an exhaust gas recirculation path. As shown in Fig. 1, a shell & tube type heat exchanger is used as the EGR cooler 4 for cooling down the exhaust gas and supplying the cooled exhaust gas. Also, a 1-pass straight- tube type heat exchanger is used as the EGR cooler 4, where the exhaust gas passes in one direction. The coolant of an engine 10 is used as a shell fluid. The coolant flows in through a coolant inlet 7in and flows out through a coolant outlet 7out. An exhaust gas is used as a tube fluid. The exhaust gas flows in through a right side pipe 6in extending from the exhaust manifold 3 and flows out through a left side pipe 6out extending to the intake manifold 2. A reference numeral 11 denotes a combustion chamber.

[9] Figs. 2 and 3 illustrate an EGR cooler 4 having a 2-pass straight-tube type heat exchanger. The EGR cooler 4 includes a body shell 4a, a plurality of inlet tubes 5in disposed in the body shell 4a, and a plurality of outlet tubes 5out. The inlet tube 5in and the outlet tubes 5out have a form of a pipe having a circular section.

[10] The inside of the body shell 4a is divided into an exhaust gas inlet area 4b formed by a plurality of inlet tubes 5in and an exhaust gas outlet area 4c formed by a plurality of outlet tube 5out. The coolant of an engine flows in and flows out through an inlet 7in and an outlet 7out, which are disposed at a side of the body shell 4a.

[11] A flange 6 is disposed at one end of the body shell 4a. The flange 6 includes openings 12a and 12b for admitting the exhaust gas flow in and out. A U-Flow cap 13 is disposed at the other end of the body shell 4a.

[12] By dividing the openings 12a and 12b of the flange 6 using a dividing bar 12, an inlet opening 12a and an outlet opening 12b are formed for letting an exhaust gas flowing in and out. The inlet tubes 5in and the outlet tubes 5out are divided corresponding to the inlet opening 12a and the outlet opening 12b.

[13] An EGR valve (not shown) is disposed at the opening side of the flange 6, and the

EGR valve (not shown) opens or closes the inlet opening 12a and the outlet opening 12b.

[14] An exhaust gas flows in through the exhaust gas inlet opening 12a. Then, the exhaust gas passes through the inlet tubes 5in, makes U-turn along the U-Flow cap 13, passes through the outlet tubes 5out, and is discharged through the exhaust gas outlet opening 12b. The discharged exhaust gas flows in a right pipe 6out connected to an intake manifold 2 of Fig. 1.

[15] As shown, the conventional EGR cooler has a complicated structure. Due to such a complicated structure, the conventional EGR cooler had following shortcomings. That is, the manufacturing cost increased because many elements were required to manufacture the conventional EGR cooler. Also, the cooling efficiency deteriorated, and the conventional EGR cooler occupied a large space in a vehicle.

[16] In order to overcome such shortcomings, the applicant of the present invention also filed applications including Korea Patent Application No. 10-2007-20344 entitled "EGR cooler", Korea Patent Application No. 10-2007-20350 entitled "Plastic EGR cooler", and Korea Patent Application No. 10-2007-20354 entitled "Stack type EGR cooler".

[17] Those EGR coolers introduced by the applicant have a simpler structure than a conventional EGR cooler, thereby reducing a manufacturing cost, occupying a smaller space in a vehicle, and improving the cooling efficiency of an exhaust gas.

[18] Meanwhile, the inlet opening 12a and the outlet opening 12b of the flange 6 are equivalent in an area by disposing the dividing bar 12 of the flange 6 at the middle thereof in the conventional EGR cooler and the EGR coolers of the present applicant.

[19] Since the inlet opening 12a and the outlet opening 12b have the same area in the conventional EGR cooler, the difference between an inlet velocity and an outlet velocity is great. That is, the inlet velocity and the outlet velocity are not constant. Therefore, fouling is greatly generated at an outlet side, and the particulate matter (PM) of the exhaust gas may block a pipe.

[20] Due to the increment of the fouling, the pressure of an exhaust gas is seriously dropped as time passes, and the performance of cooling the exhaust gas also abruptly deteriorates. Disclosure of Invention

Technical Problem

[21] An embodiment of the present invention is directed to providing an ERG cooler for constantly sustaining an inlet velocity and an outlet velocity of an exhaust gas in a cooler by unequally partitioning an inlet area and an outlet area in a cooler, thereby reducing the generation of fouling, minimizing pressure drop, and greatly improving a performance of cooling an exhaust gas.

[22] Other objects and advantages of the present invention can be understood by the following description, and become apparent with reference to the embodiments of the present invention. Also, it is obvious to those skilled in the art of the present invention that the objects and advantages of the present invention can be realized by the means as claimed and combinations thereof. Technical Solution

[23] In accordance with an aspect of the present invention, there is provided an exhaust gas recirculation (EGR) cooler having a plurality of tubes for enabling an exhaust gas to pass, a coolant path between tubes for enabling a coolant to pass, and a coolant inlet and a coolant outlet communicating with the coolant path, including: a flange disposed at one end of the tube and having an exhaust gas inlet opening and an exhaust gas outlet opening; and a closing cap disposed at the other end of the tube, wherein the exhaust gas inlet opening and the exhaust gas outlet opening are unequally partitioned by a dividing bar, and the exhaust gas inlet opening has a larger area than the exhaust gas outlet opening.

[24] The flange may include an EGR valve for controlling inflow and outflow of an exhaust gas, the EGR valve may include a valve housing having an exhaust gas inlet path and an exhaust gas outlet path which are partitioned by a barrier rib, and a valve member for opening and closing the exhaust gas inlet path and the exhaust gas outlet path, and the barrier rib of the valve housing may be disposed at a predetermined position corresponding to the dividing bar of the flange.

[25] The tube may internally include a wave fin.

[26] The EGR cooler may further include a body shell housing a plurality of the tubes.

Advantageous Effects

[27] In an EGR cooler according to an embodiment of the present invention, an exhaust gas inlet opening and an exhaust gas outlet opening are unequally partitioned. Particularly, the exhaust gas inlet operating has a larger area than the exhaust gas outlet opening. Therefore, the generation of fouling can be minimized by constantly maintaining an inlet velocity and an outlet velocity of an exhaust gas. Brief Description of the Drawings [28] Fig. 1 is a diagram illustrating an exhaust gas recirculation (EGR) system.

[29] Fig. 2 is a perspective view of an EGR cooler according to the related art.

[30] Fig. 3 is a cross-sectional view of Fig. 2 taken along the line W-W.

[31] Fig. 4 is an exploded perspective view of an EGR cooler according to an embodiment of the present invention. [32] Fig. 5 is a perspective view of an EGR cooler according to an embodiment of the present invention.

[33] Fig. 6 is a cross-sectional view of Fig. 5 taken along the line X-X.

[34] Fig. 7 is an exploded perspective view of an EGR cooler according to another embodiment of the present invention. [35] Fig. 8 is a perspective view of an EGR cooler according to another embodiment of the present invention.

[36] Fig. 9 is a cross-sectional view of Fig. 8 taken along the line Y-Y.

[37] Fig. 10 is a graph showing the velocity magnitude of an EGR cooler according to an embodiment of the present invention.

Mode for the Invention [38] The advantages, features and aspects of the invention will become apparent from the following description of the embodiments with reference to the accompanying drawings, which is set forth hereinafter. [39] Figs. 4 to 6 are diagrams illustrating an EGR cooler according to an embodiment of the present invention. [40] As shown in Figs. 4 and 5, the EGR cooler 100 has a structure of a shell & tube type heat exchange. That is, the EGR cooler 100 includes a body shell 110 and a plurality of tubes 120 disposed in the body shell 110. [41] Both ends of the body shell 110 are opened. The body shell 110 includes a coolant inlet pipe 111 for receiving a coolant and a coolant outlet pipe 112 for outputting a coolant, which are disposed at the outer surface thereof. [42] The body shell 110 includes a flange 140 having openings 141 and 142 at one end thereof. The flange 140 may be integrally formed with the body shell 110, or the flange

140 may be assembled with the body shell 110 in attachable/detachable manner. The body shell 110 also includes a closing cap 150 at the other end thereof. [43] Coolant paths 113 are formed between the inner surface of the body shell 110 and a plurality of tubes 120 and between the tubes 120. The coolant paths 113 are communicated with the coolant inlet pipe 111 and the coolant outlet pipe 112. [44] The flange 140 includes openings 141 and 142. The openings 141 and 142 are partitioned by a dividing bar 145 into an inlet opening 141 for enabling an exhaust gas to flow in and an outlet opening 142 for enabling an exhaust gas to flow out. Here, the inlet opening 141 has a larger area than the outlet opening 142. That is, the dividing bar 145 is disposed at a predetermined position that forms the inlet opening 141 larger than the outlet opening 142 in an area.

[45] A plurality of tubes 120 are disposed in the body shell 110. Each of the tubes 120 has an oval section. However, each of the tubes 120 may have a circular section like the tubes shown in Figs. 2 and 3.

[46] As shown in Fig. 6, one end of each tube 120 communicates with the openings 141 and 142 of the flange 140, and the other end of each tube 120 is closed by the closing cap 150.

[47] Each tube 120 internally includes a wave fin 130. The wave fin 130 is a wrinkled plate with a curved waveform or a straight waveform formed. Grooved parts and raised parts of the wave fin 130, which are formed by the waveform of the wave fin 130, form channels for enabling an exhaust gas to pass. It is preferable that a pitch of the wave fin 130 is about 4.0mm to 6.0mm, where the pitch is a distance between two adjacent raised parts or grooved parts. Also, a rugged portion is formed on the surface of the wave fin 130. The rugged portion enlarges a heat transfer area, thereby easily forming a turbulent flow. The wave fin 130 improves the performance of cooling an exhaust gas.

[48] One end of the wave fin 130 communicates with the openings 141 and 142 of the flange 140 and the other end is separated from the closing cap 150, thereby forming a U-turn area 160 for guiding an exhaust gas to make a U-turn.

[49] Each tube 120 is divided into an inlet area 121 and an outlet area 122 corresponding to the inlet opening 141 and the outlet opening 142 of the flange 140. According to the dividing bar 145, the inlet area 121 of each tube 120 has a larger area than the outlet area 122 corresponding to the inlet opening 141 and the outlet opening of the flange 140.

[50] An EGR valve 170 is disposed at the flange side for selectively opening and closing the inlet opening 141 and the outlet opening 142 of the flange 140. The EGR valve 170 makes an exhaust gas to flow in the EGR cooler 100 from an exhaust manifold (3 in Fig. 1) and makes a cooled exhaust gas to flow out to an intake manifold (2 in Fig. 1) by selectively opening and closing the inlet opening 141 and the outlet opening 142 of the flange 140.

[51] For reference, the other elements of the EGR cooler were described in detail in

Korea Patent Application No. 10-2007-20344 entitled "EGR cooler" and Korea Patent Application No. 10-2007-20350 entitled "Plastic EGR cooler", which were filed by the applicant of the present invention.

[52] The EGR valve 170 includes a valve housing 171 having an inlet path 171a and an outlet path 171b, a valve member 172 for selectively opening and closing the inlet path 171a and the outlet path 171b, and a driving unit 173 for driving the valve member 172.

[53] The valve housing 171 includes the inlet path 171a and the outlet path 171b, which are divided by a partition wall 171c. The partition wall 171c is disposed at a predetermined position in the valve housing 171 corresponding to the dividing bar 145 of the flange 140. Therefore, the inlet path 171a of the valve housing 171 corresponds to the inlet opening 141 of the flange 140, and the outlet path 171b of the valve housing 171 corresponds to the outlet opening 142 of the flange 140.

[54] The valve member 172 is formed in a cylinder shape. Such a shape of the valve member 172 enables the valve member 172 to control an inflow amount and a discharge amount of an exhaust gas by properly controlling an opening degree thereof as well as selectively opening and closing the inlet path and the outlet path 171a and 171b.

[55] And, the driving unit 173 includes a driving shaft 173a pivotally disposed at the valve housing side, an operating link 173b for making the driving shaft 173a to a pivot motion , and a transformer (not shown) for transforming the pivot motion of the driving shaft 173a to a straight motion of the valve member 172.

[56] The configuration and the constituent elements of the EGR valve 171 according to the present embodiment such as the valve member 172 and the driving unit 173 may change in various forms except that the inlet path 171a and the outlet path 171b are divided unequally by the partition wall 171c.

[57] Figs. 7 to 9 illustrate an EGR cooler according to another embodiment of the present invention.

[58] As shown in Figs. 7 and 8, the EGR cooler 200 according to the present embodiment is a stack type cooler where a plurality of tubes 220 are stacked thereon. That is, the EGR cooler 200 does not include a body shell.

[59] As shown, a plurality of tubes 220 are stacked thereon, and a coolant path (not shown) is formed between tubes 220 for a coolant passing through.

[60] A second adaptor 320 is disposed at one end of the stacked tubes 220. A coolant outlet pipe 212 is connected to the second adaptor 320. A first adaptor 310 is disposed at the other end, and a coolant inlet pipe 211 is connected to the first adaptor 310. A coolant path 330 is formed between the first and second adaptors 320 and 330 and the tube 220, and between the stacked tubes 220. The coolant path 330 communicates with the coolant inlet pipe 211 and the coolant outlet pipe 212.

[61] As shown in Fig. 9, one end of each tube 220 communicates with openings 241 and

242 of a flange 240, and the other end of each tube 220 is closed by a closing cap 250.

[62] Each tube 220 internally includes a wave fin 230. The wave fin 230 is a wrinkled plate with a curved waveform or a straight waveform formed. Grooved parts and raised parts of the wave fin 230, which are formed by the waveform of the wave fin 230, form channels for passing an exhaust gas. It is preferable that a pitch of the wave fin 230 is about 4.0mm to 6.0mm, where the pitch is a distance between two adjacent raised parts or grooved parts. Also, a rugged portion is formed on the surface of the wave fin 230. The rugged portion enlarges a heat transfer area, thereby easily forming a turbulent flow. The wave fin 230 improves the performance of cooling an exhaust gas.

[63] One end of the wave fin 130 communicates with the openings 241 and 242 of the flange 240 and the other end is separated from the closing cap 250, thereby forming a U-turn area 260 for allowing an exhaust gas to make a U-turn.

[64] Each tube 220 is divided into an inlet area 221 and an outlet area 222 corresponding to the inlet opening 241 and the outlet opening 242 of the flange 240. According to the dividing bar 245, the inlet area 221 of each tube 220 has a larger area than the outlet area 222 corresponding to the inlet opening 241 and the outlet opening of the flange 240.

[65] The first adaptor 310 may be integrally formed at the flange side 240 or provided at the flange side 240 in an attachable/datable manner. The second adaptor 320 is disposed at the closing cap side 250.

[66] The flange 240 includes opening 241 and 242. The openings 241 and 242 are divided by the dividing bar 245 into an inlet opening 241 for enabling an exhaust gas to flow in and an outlet opening 242 for enabling an exhaust gas to flow out. The inlet opening 241 has a larger area than the outlet opening 242. That is, the dividing bar 245 is disposed at a predetermined position that partitions the inlet opening 241 to have a larger area than the outlet opening 242.

[67] The dividing bar 245 is disposed at a predetermined position (unequal divisional position) that partitions the inlet opening 241 to have a larger area than the outlet opening 242.

[68] An EGR valve 270 is disposed at the flange side for selectively opening and closing the inlet opening 241 and the outlet opening 242 of the flange 240. The EGR valve 270 makes an exhaust gas to flow in the EGR cooler 200 from an exhaust manifold (3 in Fig. 1) and makes a cooled exhaust gas to flow out to an intake manifold (2 in Fig. 1) by selectively opening and closing the inlet opening 241 and the outlet opening 242 of the flange 240.

[69] For reference, the other constituent elements of the EGR cooler were described in detail in Korea Patent Application No. 10-2007-20354 entitled "Stack Type EGR Cooler", which was filed by the applicant of the present invention.

[70] The EGR valve 270 includes a valve housing 271 having an inlet path 27 Ia and an outlet path 271b, a valve member 272 for selectively opening and closing the inlet path 271a and the outlet path 271b, and a driving unit 273 for driving the valve member 272.

[71] The valve housing 271 includes the inlet path 27 Ia and the outlet path 27 Ib, which are divided by a partition wall 271c. The partition wall 271c is disposed at a predetermined position in the valve housing 271 corresponding to the dividing bar 245 of the flange 240. Therefore, the inlet path 271a of the valve housing 271 corresponds to the inlet opening 241 of the flange 240, and the outlet path 271b of the valve housing 271 corresponds to the outlet opening 242 of the flange 240.

[72] The valve member 272 is formed in a cylindrical shape. Such a shape of the valve member 272 enables the valve member 272 to control an inflow amount and a discharge amount of an exhaust gas by properly controlling an opening degree thereof as well as selectively opening and closing the inlet path and the outlet path 271a and 271b.

[73] And, the driving unit 273 includes a driving shaft 273 a pivotally disposed at the valve housing side, an operating link 273b for making the driving shaft 273a to a pivot motion , and a transformer (not shown) for transforming the pivot motion of the driving shaft 273a to a straight motion of the valve member 272.

[74] The configuration and the constituent elements of the EGR valve 271 according to the present embodiment such as the valve member 272 and the driving unit 273 may change in various forms except that the inlet path 271a and the outlet path 271b are divided unequally by the partition wall 271c.

[75] Fig. 10 is a graph illustrating velocities varying according to a partition ratio of an inlet opening and an outlet opening of a flange.

[76] Here, an inflow pressure of an exhaust gas was about 2.61bar (Abs.), and a temperature of a position A in Figs. 6 to 9 was set to about 133⁰C.

[77] Based on the conditions, an inlet velocity and an outlet velocity were measured at positions A, B, C, and D using a density and an area while changing a partition ratio of an inlet opening and an outlet opening. Table 1 shows the result of measuring the inlet and outlet velocities.

[78] Table 1

[79] Referring to Fig. 10 and Table 1, a difference between an inlet velocity of a position

A and an outlet velocity of a position D is about 6.7 when a partition ratio of an inlet opening and an outlet opening is 55:45. A difference between an inlet velocity of a position A and an outlet velocity of a position D is about 3.2 when a partition ratio of an inlet opening and an outlet opening is 60:40. On the contrary, a difference between an inlet velocity of a position A and an outlet velocity of a position D is about 10.2 when a partition ratio of an inlet opening and an outlet opening is 50:50.

[80] That is, when the inlet opening has a larger area than the outlet opening, the different between the inlet side velocity (position A) and the outlet side velocity (position B) becomes smaller compared to that the inlet opening and the outlet opening have the same area.

[81] In the EGR cooler according to the present invention, the inlet opening and the outlet opening are formed to have an unequal area. Therefore, the inlet velocity and the outlet velocity of the exhaust gas can be equally sustained, thereby minimizing the generation of fouling.

[82] Due to the minimization of fouling, pressure dropping can be also minimized and a performance of cooling an exhaust gas can be greatly improved.

[83] As described above, the EGR cooler according to the present invention has the inlet opening having an area larger than the outlet opening as the technical characteristics. Therefore, the EGR cooler according to the present invention can minimize the generation of fouling by sustaining the inlet velocity and the outlet velocity of an exhaust gas equally.

[84] Although the EGR cooler according to the embodiment of the present invention was described to have a shell & tube type heat exchanger like Figs. 2 and 4 or to have a stack type heat exchanger like Fig. 7, the present invention is not limited thereto. That is, the present invention can be applied to various structures of EGR coolers if an inlet opening of an exhaust gas and an outlet opening of an exhaust gas are formed to have an unequal area.

[85] While the present invention has been described with respect to certain preferred embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirits and scope of the invention as defined in the following claims.

Claims

[1] An exhaust gas recirculation (EGR) cooler having a plurality of tubes for enabling an exhaust gas to pass, a coolant path between tubes for enabling a coolant to pass, and a coolant inlet and a coolant outlet communicating with the coolant path, comprising: a flange disposed at one end of the tube and having an exhaust gas inlet opening and an exhaust gas outlet opening; and a closing cap disposed at the other end of the tube, wherein the exhaust gas inlet opening and the exhaust gas outlet opening are unequally partitioned by a dividing bar, and the exhaust gas inlet opening has a larger area than the exhaust gas outlet opening.

[2] The EGR cooler of claim 1, wherein the flange includes an EGR valve for controlling inflow and outflow of an exhaust gas, the EGR value includes a valve housing having an exhaust gas inlet path and an exhaust gas outlet path which are partitioned by a barrier rib, and a valve member for opening and closing the exhaust gas inlet path and the exhaust gas outlet path, and the barrier rib of the valve housing is disposed at a predetermined position corresponding to the dividing bar of the flange.

[3] The EGR cooler of claim 1, wherein the tube internally includes a wave fin.

[4] The EGR cooler of any one of claims 1 and 3, further comprising a body shell housing a plurality of the tubes.