JP2005083193A - Exhaust device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently secure the support rigidity of a collecting exhaust pipe while simplifying structure to reduce the number of part items, assembling man-hours and cost by connecting the collecting exhaust pipe overhanging from an exhaust pipe mounting flange of an exhaust manifold, to the exhaust pipe mounting flange by an exhaust return pipe, and integrally forming an exhaust return pipe part of the same material as the exhaust manifold in an exhaust device for an internal combustion engine. <P>SOLUTION: In the exhaust device wherein the collecting exhaust pipe of the exhaust manifold overhangs from the exhaust pipe mounting flange, the exhaust collecting pipe is extended to face an exhaust return hole of a cylinder head, and the exhaust return pipe is provided to annularly surround a space part formed among the exhaust pipe mounting flange, an independent exhaust pipe and the exhaust collecting pipe. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust system for an internal combustion engine, and more particularly to an exhaust system for an internal combustion engine that recirculates a part of exhaust gas extracted from an exhaust system to an intake system.

  2. Description of the Related Art An internal combustion engine of a vehicle is provided with an exhaust device that extracts a part of exhaust gas from an exhaust system and recirculates the exhaust gas to an intake system to reduce a combustion temperature in a combustion chamber to reduce exhaust harmful components such as NOx.

  In this exhaust apparatus, although not shown, a plurality of exhaust holes arranged along the cylinder row direction and opened on the exhaust pipe mounting surface of the cylinder head of the multi-cylinder internal combustion engine, and the arrangement of the exhaust holes An exhaust gas recirculation hole opened on one side of the direction is provided. As shown in FIGS. 7 to 9, an exhaust manifold 102 attached to a cylinder head of an internal combustion engine for multiple cylinders (4 cylinders: # 1, # 2, # 3, # 4) is an exhaust pipe of the cylinder head. An exhaust pipe mounting flange 104 that is joined to the mounting surface and covers each exhaust hole and exhaust recirculation hole, and first to fourth exhaust communication holes 106-whose upstream end communicates with the exhaust hole via the exhaust pipe mounting flange 104. The first to fourth independent exhaust pipes 108-1 to 108-4 forming the first to 106-4, the first independent exhaust pipe 108-1 and the fourth independent exhaust pipe 108-4 are connected to each other in the cylinder row direction. The one-side exhaust connection pipe 110 directed to Z, the second independent exhaust pipe 108-2, and the third independent exhaust pipe 108-3 are connected to each other and oriented in the cylinder row direction Z and substantially the same as the one-side exhaust connection pipe 110. Parallel other-side exhaust connection pipe 112 and first to fourth independent exhaust pipes 1 8-1 to 108-4 are connected to the downstream ends of the one-side exhaust coupling pipe 110 and the other-side exhaust coupling pipe 112 so as to be connected to the downstream ends of the cylinders 8-1 to 108-4. There are also provided an exhaust gas collecting pipe 114 and an exhaust gas recirculation passage 116 that branches from the exhaust gas collecting pipe 114 and functions as an exhaust gas recirculation pipe that communicates with the exhaust gas recirculation hole of the cylinder head through the exhaust pipe mounting flange 104. .

  The exhaust manifold 102 is made of cast iron and is attached to the exhaust pipe mounting surface of the cylinder head via a gasket (not shown). The exhaust collecting pipe 114 overhangs on the vehicle rear side of the exhaust pipe mounting flange 104. Arranged. The exhaust gas recirculation passage 116 is formed at the rear end portion 104A of the exhaust pipe mounting flange 104, and the exhaust gas recirculation hole in the fourth independent collecting pipe 108-4 and the cylinder head is utilized by utilizing the thickness of the exhaust pipe mounting flange 104. Is formed to communicate with each other.

Conventionally, some exhaust systems for internal combustion engines have an exhaust manifold attached to a cylinder head so that the exhaust gas introduction passage of the exhaust manifold and the first exhaust gas passage of the cylinder head communicate with each other.
Some exhaust devices for internal combustion engines are provided with a passage forming member that forms part of the exhaust passage in cooperation with the outer surface of the mounting flange of the exhaust manifold.
JP-A-10-122061 JP 2001-193574 A

  However, conventionally, as shown in FIG. 7, in an exhaust system of an internal combustion engine that recirculates a part of the exhaust extracted from the exhaust system to the intake system, the exhaust manifold pipe portion of the exhaust manifold overhangs from the exhaust pipe mounting flange. Therefore, an excessive load is generated on the exhaust pipe mounting flange due to the vibration of the internal combustion engine, and therefore there is a problem that the support rigidity of the exhaust manifold of the exhaust manifold is low, and in order to eliminate this problem, If the exhaust collecting pipe is supported by a reinforcing material such as a reinforcing stay made of a material different from that of the exhaust manifold, the support rigidity may be insufficient due to the structure of the exhaust manifold. There was an inconvenience that the number of man-hours increased and the cost increased.

  The present invention includes a plurality of exhaust holes arranged along a cylinder row direction on an exhaust pipe mounting surface of a cylinder head, an exhaust gas recirculation hole opened at one side portion in the arrangement direction of the exhaust holes, and the exhaust pipe mounting surface An exhaust pipe mounting flange that is joined to the exhaust hole and covers the exhaust recirculation hole, an independent exhaust pipe having an upstream end communicating with the exhaust hole through the exhaust pipe mounting flange, and a downstream end of the independent exhaust pipe An exhaust system for an internal combustion engine, comprising: an exhaust collecting pipe connected to a portion; and an exhaust recirculation pipe branched from the exhaust collecting pipe and communicating with the exhaust recirculation hole via the exhaust pipe mounting flange. The exhaust gas recirculation pipe is extended so as to face the exhaust gas recirculation hole, and the exhaust gas recirculation pipe is annularly surrounded by a space formed between the exhaust pipe attachment flange, the independent exhaust pipe, and the exhaust gas collecting pipe. Specially provided To.

  In the exhaust system for an internal combustion engine of the present invention, in the exhaust manifold in which the exhaust collecting pipe portion overhangs from the exhaust pipe mounting flange, the exhaust collecting pipe overhanging from the exhaust pipe mounting flange is connected to the exhaust pipe mounting flange via the exhaust recirculation pipe. In addition, the exhaust gas recirculation pipe is integrally molded from the same material as the exhaust manifold, ensuring sufficient support rigidity for the exhaust collecting pipe, simplifying the configuration, reducing the number of parts and assembly steps, and reducing costs. Can be lowered.

The present invention realizes the object of sufficiently securing the support rigidity of the exhaust collecting pipe by connecting the exhaust collecting pipe overhanging from the exhaust pipe mounting flange to the exhaust pipe mounting flange via the exhaust recirculation pipe. is there.
Hereinafter, embodiments of the present invention will be described in detail and specifically with reference to the drawings.

  1 to 5 show a first embodiment of the present invention.

  In FIG. 4, 2 is an internal combustion engine for a multi-cylinder (4 cylinders: # 1, # 2, # 3, # 4) mounted vertically in a vehicle (not shown), 4 is a cylinder block, and 6 is a cylinder. A head 8 is an exhaust device.

  An exhaust manifold 14 is attached to the cylinder head 6 via a gasket 12 on the left exhaust pipe mounting surface 10 which is the exhaust side.

  The exhaust pipe mounting surface 10 of the cylinder head 6 has a plurality of first to fourth exhaust holes (exhaust ports) 16-1 to 16-4 arranged along the cylinder row direction Z and opened corresponding to each cylinder. And the exhaust gas recirculation hole 18 that opens to the rear end that is one side of the arrangement direction of the first to fourth exhaust holes 16-1 to 16-4, and the first to fourth exhaust holes 16-1 to 16-1. A plurality of bolt mounting holes 20 are formed around 16-4 and the exhaust gas recirculation hole 18.

  The gasket 12 includes first to fourth exhaust gasket holes 22-1 to 22-4 corresponding to the first to fourth exhaust holes 16-1 to 16-4 and exhaust recirculation corresponding to the exhaust recirculation holes 18. Gasket holes 24, and a plurality of bolt gasket holes 26 corresponding to the bolt mounting holes 20 around the first to fourth exhaust gasket holes 22-1 to 22-4 and the exhaust gas recirculation gasket holes 24; The first to fourth exhaust side sealing beads 28-1 to 28-4 around the first to fourth exhaust gasket holes 22-1 to 22-4 and the exhaust gas recirculation side around the exhaust gas recirculation gasket hole 24 A sealing bead 30 is formed.

  The exhaust manifold 14 is made of cast iron and is joined to the exhaust pipe mounting surface 10 of the cylinder head 6 to cover the first to fourth exhaust holes 16-1 to 16-4 and the exhaust recirculation hole 18 of the cylinder head 6. The mounting flange 32 and the first to fourth exhaust communication holes 34-1 to 34-4 whose upstream ends communicate with the first to fourth exhaust holes 16-1 to 16-4 via the exhaust pipe mounting flange 32. The first to fourth independent exhaust pipes 36-1 to 36-4, the first independent exhaust pipe 36-1, and the fourth independent exhaust pipe 36-4 are connected to each other in the cylinder row direction Z. The side exhaust connection pipe 38, the second independent exhaust pipe 36-2 and the third independent exhaust pipe 36-3 are connected to each other, and the other side exhaust substantially parallel to the one side exhaust connection pipe 38 in the cylinder row direction Z is connected. The connection pipe 40 and the first to fourth independent exhaust pipes 36-1 to 36-4 are connected to the downstream ends thereof, An exhaust collecting pipe (exhaust collecting section) 42 connected to the downstream end of the side exhaust connecting pipe 38 and the other side exhaust connecting pipe 40, and a cylinder branched from the exhaust collecting pipe 42 and via the exhaust pipe mounting flange 32 An exhaust gas recirculation pipe 46 that forms an exhaust gas recirculation passage 44 that communicates with the exhaust gas recirculation hole 18 of the head 6 is provided.

  As shown in FIGS. 2 and 5, the first to fourth independent exhaust pipes 36-1 to 36-4 are disposed to the left of the vehicle orthogonal to the cylinder row direction Z. As shown in FIGS. 1 to 5, the one-side exhaust connecting pipe 38, the other-side exhaust connecting pipe 40, and the exhaust collecting pipe 38 are arranged in the cylinder row direction Z. The exhaust collecting pipe 38 extends toward the rear of the vehicle in the cylinder row direction Z so as to face the exhaust recirculation hole 18 of the cylinder head 6, and is located overhanging from the exhaust pipe mounting flange 32 to the rear of the vehicle. Yes.

  A space 48 that is a dead space is formed between the exhaust pipe mounting flange 32, the fourth independent exhaust pipe 36-4, and the exhaust collecting pipe 42. The exhaust gas recirculation pipe 46 is provided so as to surround the space 48 in an annular shape, as shown in FIGS.

  That is, as shown in FIGS. 1 to 3, in the exhaust manifold 14, the exhaust gas recirculation pipe 46 is formed as a rearward extending portion and opens to the exhaust pipe mounting flange 32 corresponding to the exhaust gas recirculation hole 18 of the cylinder head 6. It is connected to the exhaust collecting pipe 42 via a rearward extending portion 46B extending in the cylinder row direction Z from the downstream end portion 46A. As a result, the exhaust gas recirculation passage 44 formed by the exhaust gas recirculation pipe 46 communicates the collecting passage 42A in the exhaust gas collecting pipe 42 and the exhaust gas recirculation hole 18 of the cylinder head 6.

  The exhaust pipe mounting flange 32 is formed with a plurality of bolt flange holes 50 corresponding to the bolt mounting holes 20 of the cylinder head 6.

  The exhaust manifold 14 is provided with a bolt mounting boss 54 in which a plurality of bolt insertion holes 52 corresponding to predetermined bolt flange holes 50 are formed. As shown in FIGS. 2 and 5, a bolt mounting boss 54 near the exhaust gas recirculation pipe 46 is integrally provided with a support wall 56 connected to a bent portion of the exhaust gas recirculation pipe 46. The support wall 56 supports a substantially central portion of the exhaust gas recirculation pipe 46 and further increases the support rigidity of the exhaust gas recirculation pipe 46.

  The exhaust manifold 14 inserts the mounting bolt 58 into the bolt insertion hole 52 of the bolt mounting boss 54, the bolt flange hole 50 of the exhaust pipe mounting flange 32, and the bolt gasket hole 26 of the gasket 12, and the cylinder head. 6 is attached to the exhaust pipe mounting surface 10 of the cylinder head 6, and the exhaust collecting pipe 42 is positioned overhanging from the exhaust pipe mounting flange 32 to the rear of the vehicle.

  A catalytic converter mounting flange 60 is provided at the rear end of the exhaust collecting pipe 42 of the exhaust manifold 14. A plurality of converter mounting holes 62 are formed in the catalytic converter mounting flange 60.

  Next, the operation of the first embodiment will be described.

  An exhaust gas recirculation hole 18 is formed in the rear end portion, which is the end portion in the cylinder row direction Z, of the plurality of exhaust holes 16 opened on the exhaust pipe mounting surface 10 of the cylinder head 6, and the exhaust pipe of the cylinder head 6 is formed. The mounting surface 10 is fitted with an exhaust manifold 14 made of cast iron provided with an independent exhaust pipe 36 in which an exhaust communication hole 34 communicating with the exhaust hole 16 is formed at a portion of the exhaust pipe mounting flange 32 via the gasket 12.

  Each exhaust communication hole 34 of the exhaust manifold 14 extends in the cylinder row direction Z of the exhaust hole 16, an exhaust collecting pipe 42 is provided at the downstream end, and an exhaust pipe mounting flange is provided up to a position facing the exhaust collecting pipe 42. 32, and the exhaust collecting pipe 42 and the exhaust pipe mounting flange 32 are coupled via an exhaust recirculation pipe 46 communicating with the exhaust recirculation hole 18, and the exhaust recirculation pipe 46 functions as a reinforcing stay for the exhaust collecting pipe 42. The support rigidity of the exhaust collecting pipe 42 is increased.

  As a result, in the exhaust manifold 14 in which the exhaust collecting pipe 38 overhangs from the exhaust pipe mounting flange 32 to the rear of the vehicle, the exhaust collecting pipe 42 is extended so as to face the exhaust gas recirculation hole 18, and is independent from the exhaust pipe mounting flange 32. Since the exhaust gas recirculation pipe 46 is provided so as to annularly surround the space 48 formed between the pipe 36 and the exhaust gas collection pipe 42, the exhaust gas collection pipe 42 overhanging from the exhaust pipe attachment flange 32 is provided as the exhaust gas recirculation pipe. 46, the exhaust gas recirculation pipe 46 is integrally formed of the same material as that of the exhaust manifold 14, and the support rigidity of the exhaust collecting pipe 42 is sufficiently secured, and the configuration is simplified. The number of parts and assembly man-hours can be reduced and the cost can be reduced.

  Further, the exhaust gas recirculation pipe 46 is connected to the exhaust collecting pipe 42 via a rearward extending portion 46B extending in the cylinder row direction Z from the downstream end portion 46A opening to the exhaust pipe attachment flange 32 corresponding to the exhaust gas recirculation hole 18. Therefore, the rigidity of the support can be improved by joining the downstream side position of the exhaust collecting pipe 42 to the exhaust pipe mounting flange 32 with the exhaust recirculation pipe 46 having high rigidity.

  FIG. 6 shows a special configuration of the present invention and shows a second embodiment.

  The features of the second embodiment are as follows. That is, the exhaust collecting pipe 42 is integrally provided with the catalytic converter mounting flange 60 and the reinforcing rib 72 connected to the exhaust pipe mounting flange 32. An exhaust gas recirculation passage 44 is formed in the reinforcing rib 72.

  According to the configuration of the second embodiment, the reinforcing rib 72 improves the support rigidity of the exhaust collecting pipe 42, and the exhaust gas recirculation passage 44 is formed in the reinforcing rib 72, so that an additional exhaust gas recirculation pipe is not required. Thus, the configuration can be simplified.

  The structure in which the exhaust collecting pipe overhanging from the exhaust pipe mounting flange is connected to the exhaust pipe mounting flange via the exhaust recirculation pipe can also be applied to the structure of the intake pipe.

It is a side view of an exhaust manifold in the first embodiment. FIG. 2 is a bottom view of the exhaust manifold taken along arrow II in FIG. 1 in the first embodiment. FIG. 3 is a rear view of the exhaust manifold according to an arrow III in FIG. 1 in the first embodiment. It is an assembly drawing to the internal combustion engine of the exhaust manifold in the first embodiment. It is a perspective view of an exhaust manifold in the first embodiment. It is a perspective view of an exhaust manifold in the second embodiment. It is a top view of an exhaust manifold in the past. It is a front view of the exhaust pipe attachment flange of an exhaust manifold conventionally. FIG. 9 is a sectional view of an exhaust gas recirculation passage according to an arrow IX-IX in FIG.

Explanation of symbols

2 Internal combustion engine 6 Cylinder head 8 Exhaust device 10 Exhaust pipe mounting surface 12 Gasket 14 Exhaust manifold 16 Exhaust hole 36 Independent exhaust pipe 42 Exhaust collecting pipe 46 Exhaust recirculation pipe 48 Space

Claims (2)

  A plurality of exhaust holes arranged on the exhaust pipe mounting surface of the cylinder head along the cylinder row direction, an exhaust gas recirculation hole opened on one side of the exhaust hole in the arrangement direction, and joined to the exhaust pipe mounting surface An exhaust pipe mounting flange that covers the exhaust hole and the exhaust recirculation hole, an independent exhaust pipe that communicates with the exhaust hole through the exhaust pipe mounting flange, and a downstream end part of the independent exhaust pipe And an exhaust gas recirculation pipe that branches off from the exhaust gas collection pipe and communicates with the exhaust gas recirculation hole via the exhaust pipe attachment flange. And extending the exhaust pipe so as to face the hole, and providing the exhaust gas recirculation pipe so as to annularly surround a space formed between the exhaust pipe mounting flange, the independent exhaust pipe, and the exhaust collecting pipe. Features internal combustion Exhaust system of Seki.   The exhaust gas recirculation pipe is connected to the exhaust gas collecting pipe through a rearward extending portion extending in the cylinder row direction from a downstream end opening in the exhaust pipe attachment flange corresponding to the exhaust gas recirculation hole. An exhaust system for an internal combustion engine according to claim 1.

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