JP2015021437A - Internal combustion engine mounted with egr device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve unitization of a catalyst case and an EGR introduction pipe conduit of an EGR cooler without causing a problem with assembly.SOLUTION: An EGR cooler 17 mounted with an EGR introduction pipe conduit 18 is welded to a boss section 20 of a catalyst case 7 through an L-shaped joint pipe 19. Because the boss section 20 is a foundry piece, the same can be easily manufactured in a shape perfectly fitted into the catalyst case 7. The joint pipe 19 is welded to the catalyst case 17 (the EGR introduction pipe conduit 18) before being welded to the boss section 20 of the catalyst case 7. Because of no obstruction around the EGR cooler 17 when joining the joint pipe 19 and the EGR introduction pipe conduit 18 by welding, full-circled welding can be easily performed with a welding robot. Also, because of a space 45 between the EGR cooler 17 and the catalyst case 7, the joint pipe 19 and the catalyst case 17 can be easily and accurately joined by the welding with the welding robot.

Description

  The present invention relates to an internal combustion engine equipped with an EGR device, and is particularly suitable for an internal combustion engine for a vehicle (automobile).

  In an internal combustion engine for a vehicle, exhaust gas is recirculated to an intake system in order to improve fuel efficiency. In this case, if the high-temperature exhaust gas is directly recirculated, there is a problem that the charging efficiency is lowered. Therefore, a water-cooled EGR cooler is provided in the EGR pipe (EGR passage), and the engine cooling water is supplied to the EGR cooler. There are many cases where water is passed through.

  Regarding the EGR device, various proposals have been made such as, for example, the arrangement of the EGR pipe, the arrangement of the EGR cooler, or a form in which the EGR pipe is branched from the exhaust system. For example, as an example of a structure for branching an EGR pipe from an exhaust system, Patent Document 1 discloses a configuration in which an EGR pipe is directly welded to a catalyst case (conventional example) and a connection that is fitted to the lower end of the catalyst case from below. There is disclosed a configuration (invention according to the application) in which an EGR pipe portion to which an EGR pipe line is attached is integrally provided on the member, and the connection member functions as a support bracket of the catalyst case and a connection joint of the exhaust pipe.

Japanese Patent Laid-Open No. 2012-31882

  Now, the EGR pipe line becomes hot due to the high-temperature exhaust gas, but the degree of temperature rise becomes higher as it is closer to the exhaust system. For this reason, the thermal stress generated in the EGR pipe is also likely to be non-uniform. In particular, when the EGR cooler is provided in the EGR pipe, the temperature difference between the start end and the end of the EGR cooler is further increased, so that the heat load acting on the EGR pipe is also increased.

  On the other hand, as described in Patent Document 1 as a conventional example in FIGS. 6 and 7, it is possible to directly join the end portion of the EGR pipe to an exhaust system such as a catalyst case. Since it is often manufactured using pipes as a material, such direct welding methods are designed to be troublesome to process the ends so that they overlap exactly with the catalyst case, etc., and the posture of the EGR pipe If there is a change, the entire product must be remanufactured, and there is a problem that the cost associated with the design change increases.

  These problems can be solved by using a joint. In addition, when the EGR cooler is provided as described above, the EGR pipe line is used as a catalyst case or the like when the portion cooled by the EGR cooler has a structure with a large surface area and is preinstalled as a dedicated product. It cannot be directly welded to the exhaust system, and must be connected to the exhaust system via a joint.

  The present invention has been made against the background of such a situation, and as disclosed in Patent Document 1, the EGR pipe and the exhaust system are integrated to facilitate handling and assembly. The purpose is to improve the process and ease of processing (manufacturing). In addition, the present application includes many improvements that have not been made so far, and providing them can be a problem.

  The invention of the present application is an L-shaped type in which an EGR introduction pipe having a posture substantially aligned with a part of the exhaust system has one part and the other part integrally connected to a part of the exhaust system through which the exhaust gas passes. It is the structure connected by the joint pipe, Comprising: The said joint pipe is manufactured with the casting, One part of this joint pipe is joined beforehand to the said EGR introduction | transduction pipe line, The other side in the said joint pipe The EGR introduction pipe line is attached to the exhaust system by welding the end of the part to a boss provided in the exhaust system.

  The present invention also includes the structure of claim 2. That is, in the invention of claim 2, the boss portion of the exhaust system is also a cast product and is welded to the exhaust system, and either one or both of the outer surface of the joint pipe and the outer surface of the boss portion are cast. The gate trace protrusion that the time gate has hardened remains, and the gate trace protrusion is arranged on the outer corner side of the bending of the joint pipe.

  In the present invention, the EGR pipe line is connected to the boss portion of the exhaust system via a joint pipe, and the joint pipe is a cast product. It is also possible to make a complicated shape such as a thin wall.

  A welding robot is generally used for this type of welding. In the welding robot, continuous welding can be performed by moving a torch through which a wire is fed. In the present invention, the joint pipe is first an EGR pipe. Therefore, even if the interval between the joint pipe and the exhaust system is narrow, it is easy to move the tip of the welding torch around the outer periphery of the other end of the joint pipe. And a part of the joint pipe can be easily integrated (unitized).

  That is, when the joint pipe is first welded to the exhaust system, and then the joint pipe and the EGR pipe are welded, the welding torch is moved along the periphery of one end of the joint pipe. Will collide with the exhaust system, and it will be impossible to move the torch over the entire circumference. However, the joint pipe is first joined to the EGR pipe as in the present invention, and the joint pipe is In the configuration where the exhaust system is welded to the boss portion of the exhaust system, the space through which the torch passes between the EGR pipe line and the exhaust system can be easily secured. It can be realized easily.

  If the structure of Claim 2 is employ | adopted, since the joint pipe or the boss | hub part of an exhaust system can be reinforced with a gate trace protrusion, the support strength of an EGR introduction pipe line can be improved. And the gate mark protrusion is provided for casting, and the labor for cutting is unnecessary, so that the manufacturing cost can be suppressed.

  Therefore, it is possible to increase the strength of the EGR introduction pipeline while suppressing an increase in cost. If the EGR cooler is provided in the EGR introduction pipe, the EGR pipe becomes heavy. Therefore, providing the spout trace projection on the joint pipe or the boss portion increases the strength when the EGR cooler is provided. It can be said.

  Moreover, since the gate trace protrusion is provided on the outer corner side of the bending of the joint pipe, the gate trace protrusion does not interfere with the movement of the welding torch when the joint pipe is welded to the exhaust system. Therefore, the advantage that the joint pipe can be easily welded to the exhaust system is not impaired.

(A) is a front view of an embodiment, (B) is a BB view sectional view of (A) in the state where a stay was displayed. It is a side view. (A) is a plan view, (B) is a partial side view, and (C) is a sectional view taken along line IIIC-IIIC in FIG. (A) is the isolation | separation figure of the principal part seen from the IV-IV view direction of FIG. 3 (A), (B) is sectional drawing which shows the casting process of a joint pipe. (A) is the principal part front view in the middle of an assembly | attachment process, (B) is the partially broken view seen from the IV-IV view direction of FIG.

  Next, an embodiment of the present invention will be described with reference to the drawings. The present embodiment is applied to a vehicle internal combustion engine. In the following description, the terms “up”, “left”, “right”, “front” and “front” are used to specify the direction, but “up” and “down” are directions of the vertical line, “front” and “down” are directions perpendicular to the crankshaft and the cylinder bore. It is the longitudinal direction.

(1). Overview The internal combustion engine of the present embodiment includes an engine body having a cylinder block 1 and a cylinder head 2 fixed to the upper surface of the cylinder block 1, and the engine body has a crankshaft (not shown) extending in the longitudinal direction. It is mounted on the vehicle in the sideways orientation. The internal combustion engine of the present embodiment has three cylinders, and three exhaust ports 3 are opened side by side on the front surface 2a of the cylinder head 2 and an exhaust manifold 4 communicating with the exhaust port 3 is fixed. . Although it is not necessary to mention, the intake port is opened on the rear surface of the cylinder head 2 and the intake manifold is fixed.

  Since the internal combustion engine has three cylinders, the exhaust manifold 4 has three branch pipes 5 and a collecting pipe 6 communicating with them. The collecting pipe 6 is opened downward, and a catalyst case 7 having a circular cross section is fixed thereto. Further, the exhaust manifold 4 is provided with a flange 8 connected to the inlet portion of each branch pipe 5, and the flange 8 is fixed to the cylinder head 1 with a bolt (not shown). Reference numeral 9 shown in FIG. 1 is a mounting hole through which a bolt is inserted. In FIG. 1, the collecting pipe 6 is shifted to the right side from the left and right intermediate position of the exhaust manifold 4, but may be shifted to the left side or provided in the left and right intermediate part.

  The catalyst case 7 constitutes a part of the exhaust system, and a three-way catalyst is disposed inside the catalyst case 7. The catalyst case 7 has a cylindrical shape in which the upper end portion is formed as a stepped reduced diameter portion 7a and the lower end portion is constricted as a lower tapered portion 7b, and the joint pipe 10 is welded to the lower tapered portion 7b. Then, a support bracket 11 made of a metal plate is fixed to the middle of the joint pipe 10 by welding. An exhaust pipe 12 is connected to the joint pipe 10 from below. The exhaust pipe 12 also constitutes an exhaust system. A sensor mounting seat 13 is provided in the collecting pipe 6 of the exhaust manifold 4.

  The support bracket 11 extends across the joint pipe 10 in a state of being almost horizontal, and is inclined at one end (the left end in FIG. 1) to the side opposite to the catalyst case 7 in a front view and rearward in a side view. The raised portion 11a is bent. The rising portion 11a is fixed to a stay 14 fixed to the cylinder block 1 with a bolt.

  Therefore, the catalyst case 7 is supported by the cylinder block 1 via the support bracket 11 and the stay 14. As a fixing means for the support bracket 11, a nut 16 is screwed into a stud bolt 15 projecting forward from the stay 14, but a headed bolt and a nut may be used, or a bolt may be screwed into the stay 14. .

  Of the lower taper portion 7b of the catalyst case 7, on the outer peripheral surface of the support bracket 11 opposite to the rising portion 11a, a vertically long EGR introduction conduit 18 having an EGR cooler 17 is connected to the joint pipe 19 and the boss portion 20. Connected through. Therefore, the rising portion 11 a of the support bracket 11 and the EGR introduction pipe 18 with the EGR cooler 17 are located on both the left and right sides of the catalyst case 7.

  A joint pipe 21 having a circular cross section that is long in the front-rear direction is connected to the upper end of the EGR introduction pipe line 18 in the direction of the cylinder head 2, and the joint pipe 21 is connected to the cylinder head via a flange plate 22. 2 is fixed to the front surface 2a of the bolt 2 with a bolt (not shown). The flange plate 22 has a shape that is long in the vertical direction, and an upper end portion and a lower end portion are fixed to the cylinder head 2 with bolts (not shown).

  A tip portion of the joint pipe 21 fixed to the flange plate 22 is pressed and held from above by a pressing member 23 fixed to the flange plate 22 by brazing. Although not shown, an EGR passage communicating with the joint pipe 21 is formed at the right end portion of the cylinder head 2, and exhaust gas flowing into the EGR passage is passed to the intake system via an EGR valve (not shown). Reflux.

(2). Overall configuration of EGR device-related elements As described above, the EGR introduction pipe line 18 with the EGR cooler 17 is located to the right of the catalyst case 7 in the state of FIG. 1, and the EGR introduction pipe line 18 with the EGR cooler 17 is provided. Is substantially parallel to the catalyst case 7 in a front view, and is slightly inclined backward in a side view.

  As shown in FIG. 3, the attachment position with respect to the catalyst case 7 is located in front of a line X passing through the axis of the catalyst case 7 and parallel to the front surface 2 a of the cylinder head 2. That is, it is joined to a position slightly ahead of the portion directly beside the catalyst case 7. Therefore, the distance between the catalyst case 7 and the EGR cooler 17 is larger than that in the state of FIG. 1, and the distance is narrowed toward the top.

  The exhaust manifold 4 and the catalyst case 7 are covered from the front side by an insulator (not shown). Therefore, attachment pieces 25 for fixing the insulator are fixed by welding to two locations at the upper end of the exhaust manifold 4, one location on the catalyst case 7, and two locations on the rear surface of the EGR cooler 17. The right end of the insulator extends toward the space between the catalyst case 7 and the EGR cooler 17.

  The EGR introduction pipe line 18 is built in the EGR cooler 17. Therefore, formally, the EGR introduction pipe line 18 has an appearance like a part of the EGR cooler 17. As shown in FIG. 3C, the EGR introduction pipe line 18 has a configuration in which a fin pipe 18a having a cross-sectional petal shape is covered with a circular sheath pipe 18b, and the sheath pipe 18b and the EGR cooler 17 are connected to each other. Cooling water passes through the space between them.

(3). Pipe structure to the EGR cooler The EGR cooler 17 has a circular cross section and is water-cooled. For example, as shown in FIG. 1, the EGR cooler 17 is connected to a cooling water introduction pipe 26 and a cooling water discharge pipe 27. Has been. In the present embodiment, the cooling water introduction pipe 26 is connected to the rear surface of the lower end portion of the EGR cooler 17, and the cooling water discharge pipe 27 is connected to the front surface of the upper end portion of the EGR cooler 17. The inflow / outflow of the cooling water may be reversed, and the mounting positions of the pipes 26 and 17 in the circumferential direction with respect to the EGR cooler 17 can be changed without changing the height of the pipes 26 and 27. (For example, both are turned sideways.)

  Stainless steel pipes such as SUS304 in JIS are used as materials for the cooling water introduction pipe 26 and the cooling water discharge pipe 27, and a soft material tube (hose) 28 is fitted from the outside to the tip. Needless to say, the coolant introduction pipe 26 and the coolant discharge pipe 27 are much smaller in diameter than the EGR introduction pipe 19.

  Although the cooling water discharge pipe 27 is not supported by brackets, since the length is less than 10 cm, it does not bend and deform when the tube 28 is inserted. On the other hand, the cooling water introduction pipe 26 is lowered downward after exiting the EGR cooler 17, wound around the back of the lower end portion of the EGR cooler 17, and changed its posture again upward, and the length becomes considerably long. Yes.

  Therefore, the fixed piece 29 is fixed to the upward inclined portion 26 a on the distal end side by welding or brazing, and the fixed piece 29 is fixed to the rising portion 11 a of the support bracket 11 with a bolt 30. A tapped hole into which the bolt 30 is screwed is provided in the rising portion 11a of the support bracket 11, but a nut may be welded, or a stud bolt may be fixed and screwed into the nut.

  The tip end portion 26b of the cooling water introduction pipe 26 beyond the fixing portion by the bolt 30 is inclined so as to be separated from the catalyst case 7 as it goes upward in the front view as shown in FIG. 1, and in the front view in the side view as shown in FIG. Tilted. Therefore, the tube 28 can be easily fitted and removed (the catalyst case 7 and the like do not interfere with the operation).

  Since the distal end portion of the cooling water introduction pipe 26 is firmly fixed to the support bracket 11, the tube 28 can be easily fitted. Moreover, since the cooling water introduction pipe 26 is wound behind the catalyst case 7 even if it is long, it is possible to suppress a problem that the tool hits in engine maintenance or the like. Also, it does not interfere with the insulator.

  Since the tip of the coolant introduction pipe 26 protrudes outside the left end of the insulator, the tube 28 can be fitted and removed while the insulator is fixed. The tip of the cooling water discharge pipe 27 also protrudes above the insulator. Therefore, the fitting / removal of the tube 28 to / from the cooling water discharge pipe 27 can be performed with the insulator fixed. As shown in FIG. 2, the base portion of the cooling water introduction pipe 26 is supported from below by a suspension bracket 31 fixed to the EGR cooler 17 by welding.

  The joint pipe 19, the EGR cooler 17 and the EGR introduction pipe 18, the joint pipe 21, and the cooling water introduction / discharge pipes 26 and 27 constitute an EGR device, and these can be called EGR-related pipes. .

(4). Structure and manufacturing method of joint pipe As clearly shown in FIG. 4A, the joint pipe 19 has a circular cross section, and is connected to the horizontal portion 19a and the EGR introduction pipe line 18 connected to the boss portion 20 by welding. It has an upright part (vertical part) 19b to be connected and is L-shaped. In relation to the claims, the upright portion 19b corresponds to one portion and the horizontal portion 19a corresponds to the other portion. The horizontal portion 19b is straight, and its end portion enters the boss portion 20.

  Since the boss portion 20 overlaps the lower taper portion 7b of the catalyst case 7, the tip of the boss portion 20 is an inclined surface that is cut obliquely in front view. Therefore, when viewed from the side, the flange portion 20a is not a perfect circle but an ellipse. Further, the end surface of the flange 20 a is gently curved so as to exactly overlap the curved surface of the outer periphery of the tapered portion 7 b in the catalyst case 7.

  The upright portion 19b of the joint pipe 19 is provided with a small-diameter fitting portion 19c connected to the EGR introduction pipe line 18. As described above, the EGR introduction pipe line 18 surrounds the fin pipe 18a with the sheath pipe 18b. The sheath pipe 18b of the EGR introduction pipe 18 has a larger diameter than the fitting part 19c of the joint pipe 19.

  Therefore, a reduced diameter portion 18b 'is formed at both ends of the EGR introduction pipe line 18b penetrating the EGR cooler 17, and the fitting portion 19c of the joint pipe 19 is inserted into the reduced diameter portion 18b' and fixed by brazing. Brazing is performed seamlessly over the entire circumference. The reduced diameter portion 18 b ′ at the upper end of the EGR introduction pipe line 18 is also brazed to the joint pipe 21.

  The EGR cooler 17 and the EGR introduction pipe line 18 (18a, 18b) are manufactured using a metal plate or a metal pipe as a material. For example, stainless steel such as SUS304 in JIS is used. On the other hand, the joint pipe 19 and the boss 20 are cast products made of stainless steel such as SUS430 in JIS.

  FIG. 4B shows a part of the casting process of the joint pipe 19. The joint pipe 19 includes two outer molds 36 and 37, and a core mold (not shown) sandwiched and fixed between the outer molds 36 and 37. This is performed by pouring metal hot water (molten stainless steel) from the runner 39 into the cavity 38 between the core mold.

  In casting, hot water is not poured directly from the narrow runner into the cavity, but the end of the runner is used as a spout with a large area so that the hot water is diffused into the cavity. In the completed state, there are protrusions on the outer surface of the gate, and since the gate mark is usually unnecessary, it is removed with a grinder or the like.

  The manufacturing method of the joint pipe 19 according to the present embodiment is basically the same as the conventional method, and the outer molds 36 and 37 having a structure sandwiched from above and below in a posture laid sideways are used, but in this embodiment, the runner 39 is used. By providing the spout 40 at the base of the hot water, consideration is given so that the hot water quickly and uniformly flows into the cavity 38.

  Here, as an important element, the gate 40 is set to be positioned on the outer surface of the joint pipe 19 on the outer angle side. Accordingly, the gate 40 is located at the position of the mating surface of the two outer molds 36 and 37. The manufacturing method of the boss portion 20 is the same as the manufacturing method of the joint pipe 19.

  And after casting, the product is manufactured in a state where a portion corresponding to the sprue 40 and a portion corresponding to the sprue 39 are connected. In this embodiment, the portion corresponding to the sprue 39 is cut off, but the spout is formed. The portion where 40 is hardened is left as a gate mark protrusion 41. Accordingly, the gate mark protrusion 41 protrudes downward from the horizontal portion 33, and the gate mark protrusion 41 protrudes outward from the catalyst case 7 at the standing portion 34.

  Thus, if the gate mark protrusion 41 remains in the joint pipe 19 and the boss portion 20, the thickness is increased accordingly, so that the strength of the joint pipe 19 and the boss portion 20 can be increased. Further, since the flange portion 20a of the boss portion 20 can be easily manufactured even if it has a curved surface, it can be manufactured with high accuracy so as to be in close contact with the lower taper portion 7b of the catalyst case 7 over the entire circumference. For this reason, a reliable seal can be realized.

(5) Assembly of EGR cooler to catalyst case Exhaust manifold 4 and catalyst case 7 are fixed by welding, catalyst case 7 and joint pipe 19 are fixed by welding, and joint pipe 19 and EGR cooler are fixed. 17 is fixed by brazing. Further, the EGR cooler 17 (EGR introduction pipe line 18) and the joint pipe 21 are also fixed by brazing welding, and the cooling water introduction pipe 26 is connected to the catalyst case via the support bracket 11. 7 is also fixed. Therefore, the exhaust manifold 4, the catalyst case 7, and the EGR related piping are integrated (unitized). For this reason, the effort of member management and the effort of an assembly can be reduced.

  In the present embodiment, the boss portion 20 is welded to the outer peripheral surface of the catalyst case 7 in advance, and the standing portion 19b of the joint pipe 19 is first brazed to the reduced diameter portion 18b 'of the EGR introduction pipe line 18. Then, the horizontal portion 19a is partially inserted into the boss portion 20 of the catalyst case 7, and the horizontal portion 19a and the boss portion 20 are welded. The horizontal portion 19 a can be formed to have a different diameter between a fitting portion that fits into the boss portion 20 and a portion that is larger than the inner diameter of the boss portion 20.

  A welding robot is used for these welding, and as shown by dotted arrows 42 and 43 in FIG. It is welded over. The direction around the torch can be set arbitrarily.

  In this case, if the joint pipe 19 is welded to the catalyst case 7, if the torch is moved around the axis of the lower relay pipe 35a, the catalyst case 7 is obstructed and moved over the entire circumference. Can not. Therefore, welding cannot be performed accurately and efficiently using a welding robot.

  On the other hand, when the method of attaching the joint pipe 19 to the catalyst case 7 later is adopted as in the present embodiment, the welding between the lower relay pipe 35a and the joint pipe 19 can be performed without any problem using a welding robot, Since the space 45 exists between the joint pipe 19 and the catalyst case 7, the torch can be moved over the entire circumference of the horizontal portion 33 of the joint pipe 19, which is also accurate and efficient using a welding robot. Can be welded well.

  Since the boss 20 protrudes slightly, it can also be easily welded to the catalyst case 7. In the step of welding the joint pipe 19 to the boss portion 20, it is preferable to set the torch so that it starts to move from the space 45 and finishes moving at the space 45.

  When the gate mark protrusion 41 is provided on the outer corner side of the joint pipe 19 as in this embodiment, the gate mark protrusion 41 is unlikely to obstruct the movement of the welding torch when the joint pipe 19 is welded to the catalyst case 7. . That is, the gate mark protrusion 41 can be left in a state that does not interfere with welding.

(6) Advantages of Embodiment Now, the catalyst case 7, the EGR cooler 17, and the EGR introduction pipe line 18 are long in the vertical direction, and thus thermally expand in the vertical direction. In this case, if the three are thermally expanded at the same rate, distortion due to the thermal expansion can be suppressed. However, since the catalyst case 7 has the highest temperature, the amount of thermal expansion of the catalyst case 7 is the largest. The EGR introduction pipe line 18 and the EGR cooler 17 tend to be pulled downward due to the thermal expansion.

  On the other hand, the joint pipe 21 connecting the EGR cooler 17 (EGR introduction pipe line 18) and the cylinder head 2 extends in a horizontal posture and is bent in a plan view, and has a structure that bends greatly in the vertical direction. Yes. For this reason, downward movement of the EGR cooler 17 and the EGR introduction pipe line 18 is permitted by bending deformation of the joint pipe 21.

  As shown in FIG. 5 (B), since the gate mark protrusion 41 protrudes outward, when welding the joint pipe 19 to the boss portion 20 and the lower relay pipe 35a, the outer surface of the gate mark protrusion 41 is also built up. As a result, the welding strength can be improved. When the EGR cooler 17 is pulled downward by the thermal expansion of the catalyst case 7, the stress is most strongly applied to the welded portion between the lower end of the joint pipe 19 and the lower end of the boss portion 20. Therefore, in this embodiment, the bonding strength by welding is increased. It can be improved.

  As shown by the alternate long and short dash line in FIG. 5B, it is also possible to arrange the gate mark protrusion 41 on the lower surface of the boss portion 20. In this case, since the gate trace protrusion 41 of the boss | hub part 20 and the gate trace protrusion 41 of the joint pipe 10 can be welded, joining strength becomes still higher.

(7). Others The present invention can be embodied in various ways other than the above embodiment. For example, the joint object of the joint pipe of the present invention is not necessarily the catalyst case, and can be connected to a simple exhaust pipe or exhaust manifold. It is also possible to connect to an exhaust turbocharger. Furthermore, the EGR introduction pipe line may not include an EGR cooler.

  The present invention can be actually embodied in an internal combustion engine. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder head 4 Exhaust manifold 5 Exhaust manifold branch pipe 6 Exhaust manifold collection pipe 7 Catalyst case 11 Support bracket 17 EGR cooler 18 EGR introduction pipe 19 Joint pipe 19a Horizontal part (the other part)
19b Standing part (one part)
19c fitting part 20 boss part 21 joint pipe 35, 36 outer mold for casting joint pipe 40 pouring gate 41 pouring mark projection 45 space between catalyst case and EGR cooler

Claims (2)

An L-shaped joint pipe having an EGR introduction pipe line in a posture substantially aligned with a part of the exhaust system in one part of the exhaust system through which the exhaust gas passes is integrally connected to the other part. A connected configuration,
The joint pipe is manufactured by casting, and one part of the joint pipe is joined to the EGR introduction pipe in advance, and the other part of the joint pipe has a boss provided in the exhaust system. The EGR introduction pipeline is attached to the exhaust system by welding to
Internal combustion engine with EGR device. The exhaust system boss is also a cast product and is welded to the exhaust system, and one or both of the outer surface of the joint pipe and the outer surface of the boss section is a gate mark in which the metal gate during casting is solidified. A protrusion remains, and the gate mark protrusion is disposed on the outer corner side of the bending of the joint pipe.
An internal combustion engine with an EGR device according to claim 1.

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