JP2005325738A - Exhaust gas recirculation distribution pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformly distribute EGR gas introduced to an intake manifold to respective cylinders in an engine. <P>SOLUTION: The EGR distribution pipe 1 is provided with a first pipe 2, and a second pipes 3 and 4 provided on the outer circumference of it. In the first pipe 2, a tip part 2a is closed, an inlet 5 for introducing EGR gas is provided at a base end part 2b, and two first distribution holes 6a and 6b for distributing EGR to be guided out are arranged along the axial line. The first distribution hole 6b has larger opening area than the first distribution hole 6a that is closer to the inlet 5. The second pipes 3 and 4 are provided on the outer circumference of the first pipe 2 to correspond to the respective first distribution holes 6a and 6b to form a gap 7, with both ends closed. Two second distribution holes 8a and 8b are arranged along the axial line to distribute EGR gas introduced from the first distribution holes 6a and 6b to the gap 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an EGR distribution pipe for introducing and distributing EGR gas to an intake manifold of an engine.

  2. Description of the Related Art Conventionally, an EGR device that recirculates a part of exhaust gas to an intake manifold in order to reduce NOx in the exhaust gas is known as one of devices provided in an engine. On the other hand, an intake manifold made of a synthetic resin may be used due to a demand for weight reduction of the engine.

  Here, EGR gas is introduced into the intake manifold through the introduction port from the EGR pipe, but generally there is one introduction port provided in the intake manifold. For this reason, the amount of EGR gas introduced into the intake manifold from the introduction port and distributed to each cylinder tends to decrease as the arrangement of the cylinders moves away from the introduction port. Further, since the EGR gas becomes a high temperature near 280 ° C., it is necessary to take appropriate heat insulation measures in order to introduce the EGR gas into the synthetic resin intake manifold and distribute it to each cylinder. Therefore, Patent Documents 1 and 2 below describe techniques for improving EGR gas distribution and the like for each cylinder.

  The technique described in Patent Document 1 includes an EGR main pipe for introducing EGR gas into the intake manifold. A plurality of EGR branch pipes branched in parallel according to the number of branches of the intake manifold are provided on the downstream side of the EGR main pipe. These EGR branch pipes are attached to the intake manifold via a heat insulating material, and the tip portion of each EGR branch pipe is disposed in the branch pipe of the intake manifold.

The technique described in Patent Document 2 includes an exhaust gas distribution pipe connected to the EGR pipe. The exhaust gas distribution pipe is fixed to the intake manifold by fixing means. The exhaust gas distribution pipe includes a plurality of EGR gas distribution holes and is disposed in an intake passage (surge tank) of the intake manifold, and each distribution hole is disposed in the vicinity of an inlet of each branch pipe of the intake manifold.
Japanese Patent Laid-Open No. 9-317579 (page 2-4, FIGS. 1 and 2) JP 2001-123901 A (page 2-5, FIGS. 2, 3, and 11)

  However, in the technique described in Patent Document 1, a plurality of EGR branch pipes are arranged in parallel along the EGR gas flow on the downstream side of the EGR main pipe. For this reason, there is a difference in pressure loss between the EGR branch pipe closer to the upstream side and the EGR branch pipe closer to the downstream side with respect to the EGR gas flow, and the EGR gas is evenly distributed to each cylinder of the engine. There was a problem of not being.

  Similarly, in the technique described in Patent Document 2, a plurality of distribution holes are arranged in parallel along the EGR gas flow on the exhaust gas distribution pipe. For this reason, there is a difference in pressure loss between the distribution hole near the upstream side and the distribution hole near the downstream side with respect to the EGR gas flow, and the EGR gas is not evenly distributed to each cylinder of the engine. There was a problem.

  The present invention has been made in view of the above circumstances, and a first object thereof is an EGR distribution pipe capable of evenly distributing EGR gas introduced into an intake manifold to each cylinder of an engine. Is to provide. In addition to the first object, a second object of the present invention is to provide an EGR distribution pipe that can be attached to a resin intake manifold while ensuring heat insulation.

  In order to achieve the first object, the EGR distribution pipe according to the first aspect of the present invention is such that the distal end portion is closed and an inlet for introducing EGR gas is provided at the proximal end portion to distribute the EGR gas. In the EGR distribution pipe in which a plurality of distribution holes to be led out to the outside are arranged along the axis, the distribution area of each distribution hole is gradually increased from the closest to the inlet.

  According to the configuration of the above invention, the EGR gas introduced from the inlet of the base end portion is distributed to the plurality of distribution holes and led out from each distribution hole. Here, since each distribution hole has an opening area that gradually increases from the one closest to the inlet, the distribution hole closer to the tip portion where pressure loss is relatively large tends to generate EGR gas by the larger opening area, resulting in pressure loss. In the distribution hole closer to the base end, the EGR gas is less likely to be emitted due to the smaller opening area. Therefore, in each distribution hole, the ease of EGR gas emission is substantially equal due to the balance between the large pressure loss and the size of the opening area. When this EGR distribution pipe is attached to the intake manifold and each distribution hole is arranged corresponding to the inlet of each branch pipe of the intake manifold, substantially equal EGR gas is introduced into each branch pipe. .

  In order to achieve the first object, the EGR distribution pipe of the invention according to claim 2 has a distal end portion closed and an inlet for introducing EGR gas to the proximal end portion. A first pipe in which a plurality of first distribution holes for distribution and derivation are arranged along the axis, and a first pipe is provided on the outer periphery of the first pipe with a gap corresponding to each first distribution hole. A second pipe having a plurality of second distribution holes arranged along the axis is closed, and a plurality of second distribution holes for distributing the EGR gas introduced into the gaps from the first distribution holes and leading them to the outside are provided. Intended to be

  According to the configuration of the above invention, the EGR gas introduced from the inlet of the base end portion of the first pipe is distributed to the plurality of first distribution holes, and the first pipe and the second pipe are separated from each first distribution hole. Introduced into the gap between. The EGR gas introduced into the gap is further distributed to the plurality of second distribution holes of the second pipe and led out from each second distribution hole. Here, the path length from each first distribution hole to each second distribution hole is set substantially equal by the arrangement of each first distribution hole and each second distribution hole. The pressure loss is almost equal in the path to the distribution hole, and the EGR gas is easily released from each second distribution hole. The EGR distribution pipe is attached to the intake manifold, and the second distribution holes are arranged corresponding to the inlets of the branch pipes of the intake manifold, whereby substantially equal EGR gas is distributed to the branch pipes. become.

  In order to achieve the first object, an EGR distribution pipe according to a third aspect of the present invention provides the EGR distribution pipe according to the second aspect, wherein each first distribution hole has an opening area in order from the one closest to the inlet. The purpose is to gradually increase.

  According to the configuration of the above invention, in addition to the operation of the invention according to claim 2, each first distribution hole has a gradually increasing opening area in order from the one close to the inlet, so that it is closer to the tip portion where pressure loss is relatively large. In the first distribution hole, EGR gas is likely to be emitted as much as the opening area is large, and in the first distribution hole closer to the base end portion where pressure loss is relatively small, EGR gas is less likely to be emitted because of the small opening area. Accordingly, in each of the first distribution holes, the ease of EGR gas emission is substantially equal due to the balance between the large pressure loss and the size of the opening area. Therefore, the pressure loss becomes more equal in the path from each first distribution hole to each second distribution hole, and the easiness of the EGR gas from each second distribution hole becomes more equal.

  In order to achieve the first object, the EGR distribution pipe of the invention according to claim 4 has a distal end portion closed and an inlet for introducing EGR gas to the proximal end portion. A first pipe provided with at least one first distribution hole for distributing and leading out, and provided at the outer periphery of the first pipe corresponding to the first distribution hole via a first gap, and both ends are closed. In addition, a plurality of second distribution holes for distributing and leading out the EGR gas introduced into the first gap from the first distribution holes are arranged along the axis, and each second distribution hole Correspondingly, it is provided on the outer periphery of the second pipe via the second gap, both ends are closed, and the EGR gas introduced into the second gap from each second distribution hole is distributed and led to the outside. A plurality of third distribution holes provided with a third pipe arranged along the axis. And spirit of the invention.

  According to the configuration of the above invention, the EGR gas introduced from the inlet of the base end portion of the first pipe is distributed to the plurality of first distribution holes, and the first pipe and the second pipe are separated from each first distribution hole. Is introduced into the first gap between the two. The EGR gas introduced into the first gap is further distributed to the plurality of second distribution holes of the second pipe and is introduced into the second gap between the second pipe and the third pipe from each second distribution hole. The Then, the EGR gas introduced into the second gap is further distributed to the plurality of third distribution holes of the third pipe and led out from the third distribution holes. Here, each first distribution hole, each second distribution hole, and each third distribution hole are arranged so that the path length from each first distribution hole to each third distribution hole is set to be approximately equal to each other. In the path from the distribution hole to each third distribution hole, the pressure loss becomes substantially equal, and the easiness of the EGR gas from each third distribution hole becomes almost equal. The EGR distribution pipe is attached to the intake manifold, and the third distribution holes are arranged corresponding to the inlets of the branch pipes of the intake manifold, whereby substantially equal EGR gas is distributed to the branch pipes. become.

  In order to achieve the second object, in the EGR distribution pipe of the invention according to claim 5, the sleeve pipe is arranged on the outer periphery of the base end portion with a gap in the configuration of the invention of claim 1. The sleeve pipe has one end connected to the base end and the other end open to have a flange.

  According to the configuration of the invention described above, in addition to the operation of the invention described in claim 1, the base end portion of the EGR distribution pipe is supported by the intake manifold by attaching the flange of the sleeve pipe to the wall surface of the intake manifold. Here, a gap is interposed between the base end portion of the EGR distribution pipe and the sleeve pipe, and heat of the EGR gas transmitted to the EGR distribution pipe is radiated through the gap. Therefore, heat transfer from the base end portion of the EGR distribution pipe to the wall surface of the intake manifold is blocked to some extent.

  In order to achieve the second object, the EGR distribution pipe of the invention described in claim 6 is characterized in that, in the configuration of the invention of claim 1, a sleeve pipe is arranged on the outer periphery of the base end portion with a gap. The sleeve pipe has one end connected to the base end and the other end open to have a flange, and the tip end is closed by caulking, and a through hole intersecting the axis is formed on the tip side from the caulking position The purpose is to be prepared.

  According to the configuration of the invention described above, in addition to the operation of the invention described in claim 1, the base end portion of the EGR distribution pipe is supported by the intake manifold by attaching the flange of the sleeve pipe to the wall surface of the intake manifold. Further, the tip end portion of the EGR distribution pipe is supported by the intake manifold by attaching the tip end side to the wall surface of the intake manifold from the caulking position of the tip portion. Here, a gap is interposed between the base end portion of the EGR distribution pipe and the sleeve pipe, and heat of the EGR gas transmitted to the EGR distribution pipe is radiated through the gap. Further, at the tip of the EGR distribution pipe, heat transmitted to the tip is radiated through a through hole formed on the tip side. Therefore, the heat transfer from the proximal end and the distal end of the EGR distribution pipe to the wall surface of the intake manifold is blocked to some extent.

  In order to achieve the second object, an EGR distribution pipe according to a seventh aspect of the present invention is the EGR distribution pipe according to the first aspect, wherein the sleeve pipe is disposed on the outer periphery of the base end portion with a gap between the sleeve and the sleeve. The pipe has one end connected to the base end and the other end opened to have a flange, and the distal end is closed by caulking, and a through hole that intersects the axis is formed on the distal end side from the caulking position. A flange at the base end is attached to the wall surface of the intake manifold, and the distal end side is supported on the wall surface of the intake manifold through a rubber piece from the caulking position of the tip end, and each distribution hole is connected to each branch pipe of the intake manifold. It is intended to be arranged corresponding to the entrance of the.

  According to the configuration of the invention described above, in addition to the operation of the invention described in claim 1, the base end portion of the EGR distribution pipe is supported by the intake manifold by attaching the flange of the sleeve pipe to the wall surface of the intake manifold. Further, the tip end portion of the EGR distribution pipe is supported by the intake manifold by attaching the tip side from the caulking position of the tip portion to the wall surface of the intake manifold via a rubber piece. Here, a gap is interposed between the base end portion of the EGR distribution pipe and the sleeve pipe, and heat of the EGR gas transmitted to the EGR distribution pipe is radiated through the gap. Further, at the tip portion of the EGR distribution pipe, heat transmitted to the tip portion is radiated through a through hole formed on the tip side, and heat transfer to the intake manifold is blocked by the rubber piece. Therefore, the heat transfer from the EGR distribution pipe to the wall surface of the intake manifold is blocked to some extent. Since each distribution hole of the EGR distribution pipe is disposed corresponding to the inlet of each branch pipe of the intake manifold, substantially the same EGR gas is introduced into each branch pipe.

  In order to achieve the second object, an EGR distribution pipe according to an eighth aspect of the present invention is the configuration of the invention according to any one of the second to fourth aspects, wherein the EGR distribution pipe is provided on the outer periphery of the base end portion of the first pipe. The sleeve pipe is arranged through a gap, and the sleeve pipe has one end connected to the base end portion and the other end opened to have a flange.

  According to the configuration of the invention described above, in addition to the operation of the invention according to any one of claims 2 to 4, the flange of the sleeve pipe is attached to the wall surface of the intake manifold, so that the base end portion of the first pipe is interposed. An EGR distribution pipe is supported on the intake manifold. Here, a gap is interposed between the base end portion of the first pipe and the sleeve pipe, and heat of the EGR gas transmitted to the first pipe is radiated through the gap. Therefore, the heat transfer from the first pipe to the wall surface of the intake manifold is blocked to some extent.

  In order to achieve the second object, an EGR distribution pipe according to a ninth aspect of the present invention is the structure of the invention according to any one of the second to fourth aspects, wherein the EGR distribution pipe is provided on the outer periphery of the base end portion of the first pipe. The sleeve pipe is arranged through a gap, and the sleeve pipe has one end connected to the base end and the other end opened to have a flange, and the tip end of the first pipe is closed by caulking, and the caulking It is intended that a through hole intersecting with the axis of the first pipe is formed on the tip side from the position.

  According to the configuration of the invention described above, in addition to the operation of the invention according to any one of claims 2 to 4, the flange of the sleeve pipe is attached to the wall surface of the intake manifold, so that the base end portion of the first pipe is interposed. An EGR distribution pipe is supported on the intake manifold. Further, the tip side of the tip end portion of the first pipe is attached to the wall surface of the intake manifold so that the tip portion of the EGR distribution pipe is supported by the intake manifold via the tip portion of the first pipe. Here, a gap is interposed between the proximal end portion of the first pipe and the sleeve pipe, and heat of the EGR gas transmitted to the first pipe is radiated in the gap. Moreover, in the front-end | tip part of a 1st pipe, the heat | fever transmitted to a front-end | tip part is thermally radiated by the through-hole formed in the front end side. Therefore, the heat transfer from the first pipe to the wall surface of the intake manifold is blocked to some extent.

  In order to achieve the second object, an EGR distribution pipe according to a tenth aspect of the present invention is the structure of the invention according to any one of the second to fourth aspects, wherein the EGR distribution pipe is formed on the outer periphery of the base end portion of the first pipe. The sleeve pipe is arranged through a gap, and the sleeve pipe has one end connected to the base end and the other end opened to have a flange, and the tip end of the first pipe is closed by caulking, and the caulking A through hole that intersects the axis of the first pipe is formed on the tip side from the position, and a flange at the base end is attached to the wall surface of the intake manifold, and the tip side from the caulking position of the tip is via a rubber piece. It is supported by the wall surface of the intake manifold and each second distribution hole or each third distribution hole is arranged corresponding to the inlet of each branch pipe of the intake manifold.

  According to the configuration of the invention described above, in addition to the operation of the invention according to any one of claims 2 to 4, the flange of the sleeve pipe is attached to the wall surface of the intake manifold, so that the base end portion of the first pipe is interposed. An EGR distribution pipe is supported on the intake manifold. Further, the front end side of the first pipe from the caulking position is attached to the wall surface of the intake manifold via a rubber piece, so that the front end of the EGR distribution pipe is supported by the intake manifold. Here, a gap is interposed between the proximal end portion of the first pipe and the sleeve pipe, and heat of the EGR gas transmitted to the first pipe is radiated in the gap. Further, at the tip portion of the first pipe, heat transmitted to the tip portion is radiated through a through hole formed on the tip side, and heat transfer to the intake manifold is blocked by the rubber piece. Therefore, the heat transfer from the first pipe to the wall surface of the intake manifold is blocked to some extent. Since each second distribution hole or each third distribution hole is arranged corresponding to the inlet of each branch pipe of the intake manifold, substantially the same EGR gas is introduced into each branch pipe.

  According to the first aspect of the present invention, since the distribution holes are mounted on the intake manifold and are arranged corresponding to the inlets of the branch pipes of the intake manifold, substantially the same EGR gas is supplied to the branch pipes. As a result, the EGR gas introduced into the intake manifold can be evenly distributed to each cylinder of the engine.

  According to the second aspect of the present invention, the second distribution holes are attached to the intake manifold and are arranged corresponding to the inlets of the branch pipes of the intake manifold, so that the EGR is substantially equal to the branch pipes. Gas is introduced, and the EGR gas introduced into the intake manifold can be evenly distributed to each cylinder of the engine.

  According to the third aspect of the present invention, the EGR gas that is more equal to each branch pipe is introduced to the effect of the second aspect of the invention, and the EGR gas introduced into the intake manifold is reduced. It is possible to distribute more evenly to each cylinder of the engine.

  According to the fourth aspect of the present invention, the EGR is mounted on the intake manifold and the third distribution holes are arranged corresponding to the inlets of the branch pipes of the intake manifold, so that the EGR is substantially equal to the branch pipes. Gas is introduced, and the EGR gas introduced into the intake manifold can be evenly distributed to each cylinder of the engine.

  According to the invention described in claim 5, in addition to the effect of the invention described in claim 1, heat insulation is secured to the resin intake manifold by supporting the intake manifold through the flange of the sleeve pipe. The EGR distribution pipe can be installed while it is.

  According to the invention described in claim 6, in addition to the effect of the invention described in claim 1, the resin pipe is supported by the intake manifold through the front end side from the caulking position of the flange of the sleeve pipe and the front end portion. The EGR distribution pipe can be mounted while ensuring heat insulation for the intake manifold.

  According to the invention described in claim 7, in addition to the effect of the invention described in claim 1, it is possible to mount the EGR distribution pipe while ensuring heat insulation for the resin intake manifold.

  According to the invention described in claim 8, in addition to the effect of the invention described in any one of claims 2 to 4, by supporting the intake manifold via the flange of the sleeve pipe, The EGR distribution pipe can be attached while ensuring heat insulation.

  According to the ninth aspect of the present invention, in addition to the effect of the second aspect of the present invention, the sleeve is supported by the intake manifold through the front end side from the caulking position of the flange and the front end portion of the sleeve pipe. Thus, the EGR distribution pipe can be mounted while ensuring heat insulation for the resin intake manifold.

  According to the invention of claim 10, in addition to the effect of the invention of any of claims 2 to 4, the EGR distribution pipe can be attached to the resin intake manifold while ensuring heat insulation. it can.

[First Embodiment]
Hereinafter, a first embodiment in which an EGR distribution pipe of the present invention is embodied will be described in detail with reference to the drawings.

  FIG. 1 is a plan view showing the EGR distribution pipe of this embodiment. FIG. 2 is a sectional view taken along the line AA in FIG. FIG. 3 is a perspective view of the cross section of FIG.

  The metal EGR distribution pipe 1 in this embodiment has a double tube structure including a first pipe 2 and two second pipes 3 and 4 provided on the outer periphery thereof. The first pipe 2 is closed at the distal end portion 2a, and provided with an inlet 5 for introducing EGR gas into the proximal end portion 2b. Two first distribution holes 6a for distributing and leading out EGR gas, 6b are arranged along the axis. Each of the first distribution holes 6a and 6b is set so that the opening area gradually increases in order from the closest to the inlet 5. That is, the opening area of the first distribution hole 6 b far from the inlet 5 is set larger than that of the first distribution hole 6 a close to the inlet 5. Each of the second pipes 3 and 4 is provided on the outer periphery of the first pipe 2 via a gap 7 corresponding to each of the first distribution holes 6a and 6b, and both ends are closed. Each of the second pipes 3 and 4 has two second distribution holes 8a and 8b for distributing the EGR gas introduced into the gap 7 from the first distribution holes 6a and 6b and leading it to the outside. Arranged along. The first distribution holes 6 a and 6 b and the second distribution holes 8 a and 8 b are arranged on opposite sides with respect to the axis of the first pipe 2.

  In this embodiment, a sleeve pipe 9 is provided on the outer periphery of the base end portion 2 b of the first pipe 2 via a gap 10. One end of the sleeve pipe 9 is connected to the base end portion 2b of the first pipe 2 by welding, and the other end is opened to have a flange 9a. This flange 9a is fixed to a wall surface to be attached. Further, the front end portion 2 a of the first pipe 2 is blocked by the caulking 11. A through hole 12 that intersects the axis of the first pipe 2 is formed on the distal end side of the caulking 11 of the distal end portion 2a. In this embodiment, the tip 2a of the first pipe 2 is fixed to the wall surface to be attached, and a rubber piece 13 is attached to the tip 2a. That is, the front end portion 2 a is fixed to the opposite wall surface via the rubber piece 13.

  FIG. 4 shows an enlarged part of FIG. In FIG. 4, the path | route until the EGR gas introduce | transduced from the inlet 5 of the 1st pipe 2 is derived | led-out from each 2nd distribution hole 8a, 8b is shown by the arrow. The EGR gas introduced from the inlet 5 of the base end portion 2b of the first pipe 2 is distributed to the two first distribution holes 6a and 6b, and the first pipe 2 and the second pipe are respectively transmitted from the first distribution holes 6a and 6b. It is introduced into the gap 7 between 3 and 4. The EGR gas introduced into the gap 7 is further distributed to the two second distribution holes 8a and 8b in the second pipes 3 and 4, and is led out from the second distribution holes 8a and 8b.

  Here, the arrangement of the second distribution holes 8a and 8b with respect to the first distribution holes 6a and 6b is as follows. As shown in FIG. The first distribution holes 6a and 6b are set between the two second distribution holes 8a and 8b so that the path lengths to the two distribution holes 8a and 8b are substantially equal. Thereby, in the path | route from each 1st distribution hole 6a, 6b to each 2nd distribution hole 8a, 8b, the pressure loss of EGR gas becomes substantially equal, and EGR gas tends to come out from each 2nd distribution hole 8a, 8b. Are almost equal.

  In particular, in this embodiment, since the opening area of the first distribution hole 6b far from the inlet 5 is larger than that of the first distribution hole 6a close to the inlet 5, the first distribution near the tip 2a having a relatively large pressure loss. In the hole 6b, EGR gas is likely to be emitted as much as the opening area is large, and in the first distribution hole 6a near the base end portion 2b where pressure loss is relatively small, EGR gas is less likely to be emitted because of the small opening area. Accordingly, in each of the first distribution holes 6a and 6b, the ease of EGR gas emission is substantially equal due to the balance between the large pressure loss and the size of the opening area. Therefore, the pressure loss is more equal in the path from each first distribution hole 6a, 6b to each second distribution hole 8a, 8b than in the case where there is no difference in the size of the opening area of each first distribution hole. The EGR gas can be easily emitted from the second distribution holes 8a and 8b.

  In this embodiment, the EGR distribution pipe 1 is used by being mounted on a synthetic resin intake manifold. 5 to 9 show how the EGR distribution pipe 1 is attached to the intake manifold assembly 21. FIG. FIG. 5 shows a front view of the intake manifold assembly 21. FIG. 6 shows the intake manifold assembly 21 in a plan view. FIG. 7 is a perspective view showing the inside of the intake manifold assembly 21 by cutting it. FIG. 8 is a plan view showing a broken state of FIG. FIG. 9 is a front view of the broken state of FIG.

  The intake manifold assembly 21 includes an intake manifold integrated electronic throttle device 22 and other accessory parts. The electronic throttle device 22 includes a synthetic resin throttle body 23 including a bore 23a, a throttle valve 20 for opening and closing the bore 23a, and a drive unit 25 for driving the throttle valve 20. The throttle body 23 is formed integrally with an intake manifold 24 made of synthetic resin. In this embodiment, the intake manifold 24 is configured for four cylinders, and includes a surge tank 25 and four branch pipes 26 communicating with the tank 25. In the surge tank 25, a switching valve 27 for switching the intake passage is assembled in the middle of each branch pipe 26. The intake manifold 24 includes a horizontally long flange 28 that integrally connects the outlet side of each branch pipe 26 in parallel. The front side of the flange 28 is a flat opening end face 28 a including the opening 26 a of each branch pipe 26. The flange 28 is assembled to a cylinder head (not shown) of the engine. A fuel rail portion 29 having a fuel passage therein is integrally formed on the upper portion of the flange 28. A total of four fuel injection valves (injectors) 30 are attached to the flange 28 corresponding to the openings 26 a of the branch pipes 26. A pipe joint 31 for connecting a fuel line to the fuel passage is provided at one end in the longitudinal direction of the fuel rail portion 29. In addition, an electrical connector 32 for wiring is provided in the middle portion in the longitudinal direction of the fuel rail portion 29.

  As shown in FIGS. 7 to 9, in this embodiment, in the intake manifold assembly 21 described above, the EGR distribution pipe 1 is inserted into the EGR introduction hole 25 b formed in the side wall 25 a of the surge tank 25 and the intake manifold 25. It is attached to. In this embodiment, the flange 9 a of the sleeve pipe 9 is fixed to the side wall 25 a of the surge tank 25 with bolts 14. As a result, the base end 2 b of the first pipe 2, that is, the base end of the EGR distribution pipe 1 is supported by the intake manifold 24. Further, the tip end side of the end portion 2 a of the first pipe 2 is fixed to the side wall 25 a of the surge tank 25 via the rubber piece 13 from the position of the caulking 11. As a result, the leading end 2 a of the first pipe 2, that is, the leading end of the EGR distribution pipe 1 is supported by the intake manifold 24. That is, the EGR distribution pipe 1 is supported at two points on the side wall 25a of the surge tank 25 by the base end portion and the tip end portion. In this mounted state, the second distribution holes 8 a and 8 b of the second pipes 3 and 4 are arranged corresponding to the inlets of the branch pipes 26 of the intake manifold 24.

  For this reason, by using this EGR distribution pipe 1, EGR gas can be led out almost uniformly from the second distribution holes 8 a and 8 b of the second pipes 3 and 4, and EGR introduced into the intake manifold 24. Gas can be evenly distributed to each cylinder of the engine through each branch pipe 26. In particular, in this embodiment, in the first pipe 2, the opening area of the first distribution hole 6 b far from the inlet 5 is larger than that of the first distribution hole 6 a close to the inlet 5. The EGR gas led out from the second distribution holes 8a and 8b of the second pipes 3 and 4 can be made more even than the case where the EGR gas is introduced into the intake manifold 24. The distribution can be more evenly distributed to each cylinder of the engine through the branch pipe 26.

  In this embodiment, in the above-mentioned mounting state of the EGR distribution pipe 1, a gap 10 is interposed between the base end portion 2 b of the first pipe 2 and the sleeve pipe 9, and the EGR distribution pipe 1 is transmitted to the first pipe 2 through the gap 10. The heat of EGR gas is dissipated. Moreover, in the front-end | tip part 2a of the 1st pipe 2, the heat | fever transmitted to the front-end | tip part 2a is thermally radiated in the through-hole 12 formed in the front end side. Therefore, the heat transfer from the first pipe 2 to the side wall 25a of the surge tank 25 is blocked to some extent. For this reason, the EGR distribution pipe 1 can be attached to the synthetic resin intake manifold 24 while ensuring heat insulation. That is, high-temperature EGR gas is introduced into the EGR distribution pipe 1, but the high heat is not transmitted to the intake manifold 24 as it is, so that the synthetic resin intake manifold 24 can be protected from the high heat of the EGR gas. it can. In this embodiment, even if it is assumed that the temperature of the EGR gas is about “280 ° C.”, the heat transferred from the flange 9 to the intake manifold 24 can be reduced to about “130 ° C.”.

[Second Embodiment]
Next, a second embodiment in which the EGR distribution pipe of the present invention is embodied will be described in detail with reference to the drawings.

  In each embodiment described below, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and different points will be mainly described.

  FIG. 10 is a plan view showing the EGR distribution pipe of this embodiment. FIG. 11 is a cross-sectional view taken along line BB in FIG. FIG. 12 shows an enlarged part of FIG.

  The metal EGR distribution pipe 41 in this embodiment includes a first pipe 2, a second pipe 42 provided on the outer periphery of the first pipe 2, and two pipes provided on the outer periphery of the second pipe 42. A triple pipe structure including three third pipes 43 and 44 is formed. Unlike the first embodiment, the first pipe 2 is provided with one first distribution hole 6c in the middle thereof. The second pipe 42 is provided on the outer periphery of the first pipe 2 via the gap 45 corresponding to the first distribution hole 6c, and both ends are closed. The second pipe 42 has two second distribution holes 46a and 46b arranged along the axis for distributing and leading out the EGR gas introduced into the gap 45 from the first distribution hole 6c. The first distribution hole 6ac and the second distribution holes 46a and 46b are arranged on the opposite sides with respect to the axis of the first pipe 2. The third pipes 43 and 44 are provided on the outer periphery of the second pipe 42 via gaps 47 corresponding to the second distribution holes 46a and 46b, and both ends are closed. The third pipes 43 and 44 have two third distribution holes 48a and 48b on the axis line for distributing the EGR gas introduced into the gap 47 from the second distribution holes 46a and 46b and leading them to the outside. Arranged along. The second distribution holes 46 a and 46 b and the third distribution holes 48 a and 48 b are arranged on opposite sides with respect to the axis of the second pipe 42.

  In FIG. 12, the path | route until EGR gas introduce | transduced from the inlet 5 of the 1st pipe 2 is derived | led-out from each 3rd distribution hole 48a, 48b is shown by the arrow. The EGR gas introduced from the inlet 5 of the base end 2b of the first pipe 2 is introduced into the gap 45 between the first pipe 2 and the second pipe 42 from one first distribution hole 6c. The EGR gas introduced into the gap 45 is distributed to the two second distribution holes 46a and 46b in the second pipe 42, and the second pipe 42 and the third pipes 43 and 44 from the second distribution holes 46a and 46b. It is introduced into the gap 47 between the two. The EGR gas introduced into the gap 47 is further distributed to the two third distribution holes 48a and 48b in the third pipes 43 and 44, and is led out from the third distribution holes 48a and 48b.

  Here, as shown in FIG. 12, the arrangement of the second distribution holes 46a and 46b with respect to the first distribution hole 6c is such that the second pipe 42 extends from the first distribution hole 6c to the second distribution holes 46a and 46b. It is set so that the first distribution hole 6c is positioned between the two second distribution holes 46a and 46b so that the path lengths are substantially equal. Similarly, the arrangement of the third distribution holes 48a and 48b with respect to the second distribution holes 46a and 46b is such that, in the third pipes 43 and 44, the second distribution holes 46a and 46b are changed to the third distribution holes 48a and 48b. The second distribution holes 46a and 46b are set so as to be positioned between the two third distribution holes 48a and 48b so that the lengths of the paths to reach are substantially equal. Thereby, in the path from the first distribution hole 6c to each of the third distribution holes 48a and 48b, the pressure loss of EGR gas becomes substantially equal, and the EGR gas easily flows out from each of the third distribution holes 48a and 48b. Will be equal.

  Therefore, the EGR distribution pipe 41 of this embodiment is used by being attached to the surge tank 25 of the intake manifold assembly 21 in the same manner as in the first embodiment, so that the third distribution holes 48a, The EGR gas can be derived almost uniformly from 48b, and the EGR gas introduced into the intake manifold 24 can be evenly distributed to each cylinder of the engine through each branch pipe 26. Also in this embodiment, heat transfer from the first pipe 2 to the side wall 25a of the surge tank 25 to some extent is performed to a certain extent, as in the first embodiment, due to the heat insulating configuration at the distal end portion 2a and the proximal end portion 2b of the first pipe 9. Blocked. For this reason, the EGR distribution pipe 41 can be attached to the intake manifold 24 made of synthetic resin while ensuring heat insulation.

[Third Embodiment]
Next, a third embodiment in which the EGR distribution pipe of the present invention is embodied will be described in detail with reference to the drawings.

  FIG. 13 is a plan view showing the EGR distribution pipe of this embodiment. FIG. 14 is a sectional view taken along the line CC of FIG.

  The metal EGR distribution pipe 51 in this embodiment has a single tube structure including only the first pipe 2. In the first pipe 2, four distribution holes 52a, 52b, 52c and 52d for distributing and leading out EGR gas are arranged along the axis. Each of the distribution holes 52 a to 52 d is set so that the opening area gradually increases in order from the one closer to the inlet 5.

  According to the configuration of the EGR distribution pipe 51 of this embodiment described above, the EGR gas introduced from the inlet 5 of the base end portion 2b of the first pipe 2 is distributed to the four distribution holes 52a to 52d and distributed. The holes 52a to 52d are led out to the outside. Here, since each of the distribution holes 52a to 52d has an opening area that gradually increases from the one closest to the inlet 5, the distribution hole 52d closer to the distal end portion 2a having a relatively large pressure loss has a larger opening area than the EGR gas. In the distribution hole 52a closer to the base end portion 2b where pressure loss is relatively small, EGR gas is less likely to be emitted due to the smaller opening area. Accordingly, in each of the distribution holes 52a to 52d, the ease of EGR gas emission is substantially equal due to the balance between the large pressure loss and the size of the opening area. When this EGR distribution pipe 51 is attached to the intake manifold and each distribution hole is arranged corresponding to the inlet of each branch pipe of the intake manifold, substantially equal EGR gas is introduced into each branch pipe. Become.

  Accordingly, the EGR distribution pipe 51 of this embodiment is used by being attached to the surge tank 25 of the intake manifold assembly 21 in the same manner as in the first embodiment, so that the EGR gas is discharged from the distribution holes 52a to 52d of the first pipe 2. The EGR gas introduced into the intake manifold 24 can be evenly distributed to each cylinder of the engine through each branch pipe 26. Also in this embodiment, as in the first embodiment, heat transfer from the first pipe 2 to the side wall 25a of the surge tank 25 is performed to some extent due to the heat insulating configuration of the distal end portion 2a and the proximal end portion 2b of the first pipe 2. Blocked. For this reason, the EGR distribution pipe 41 can be attached to the intake manifold 24 made of synthetic resin while ensuring heat insulation.

  The present invention is not limited to the embodiments described above, and can be implemented as follows by appropriately changing a part of the configuration without departing from the spirit of the invention.

  (1) The EGR distribution pipes 1, 41, 51 of each of the above embodiments are configured to be supported at two points with respect to the intake manifold 24 by the distal end portion and the proximal end portion. On the other hand, the EGR distribution pipe may be configured to be cantilevered with respect to the intake manifold only by its base end. In this case, a through hole or a rubber piece provided at the tip of the EGR distribution pipe (first pipe) can be omitted.

  (2) In the first embodiment, the number of the first distribution holes 6a, 6b is set to two in total and the number of the second distribution holes 8a, 8b is set to four in total, corresponding to a four-cylinder engine. However, the number of the first distribution holes and the second distribution holes can be appropriately changed according to the number of cylinders of the engine.

  (3) In the second embodiment, the number of the first distribution holes 6c is one, the total number of the second distribution holes 46a and 46b is two, and the third distribution holes 48a, 48a, Although the number of 48b is set to four in total, the number of the first distribution holes, the second distribution holes, and the third distribution holes can be appropriately changed according to the number of cylinders of the engine.

  (4) In the third embodiment, the number of distribution holes 52a to 52d is set to four in total corresponding to a four-cylinder engine. However, the number of distribution holes is appropriately changed according to the number of cylinders of the engine. You can also

The top view which shows the EGR distribution pipe of 1st Embodiment. Sectional drawing along the AA line of FIG. The perspective view which shows the cross section of FIG. Sectional drawing which expands and shows a part of FIG. The front view which shows an intake manifold assembly. The top view which shows an intake manifold assembly. The perspective view which fractures | ruptures and shows an intake manifold assembly. The top view which shows the fracture | rupture state of FIG. The front view which shows the fracture | rupture state of FIG. The top view which shows the EGR distribution pipe of 2nd Embodiment. Sectional drawing along the BB line of FIG. Sectional drawing which expands and shows a part of FIG. The top view which shows the EGR distribution pipe of 3rd Embodiment. Sectional drawing along CC line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 EGR distribution pipe 2 1st pipe 2a Tip part 2b Base end part 3 2nd pipe 4 2nd pipe 5 Inlet 6a 1st distribution hole 6b 1st distribution hole 6c Distribution hole 7 Crevice 8a 2nd distribution hole 8b 2nd distribution hole 9 Sleeve pipe 9a Flange 10 Clearance 11 Caulking 12 Through hole 13 Rubber piece 24 Intake manifold 26 Branch pipe 26b Inlet 41 EGR distribution pipe 42 Second pipe 43 Third pipe 44 Third pipe 45 Clearance 46a Second distribution hole 46b Second distribution Hole 47 Clearance 48a Third distribution hole 48b Third distribution hole 51 EGR distribution pipe 52a Distribution hole 52b Distribution hole 52c Distribution hole 52d Distribution hole

Claims (10)

EGR distribution in which a distal end portion is blocked and an inlet for introducing EGR gas is provided at a proximal end portion, and a plurality of distribution holes for distributing the EGR gas and leading it to the outside are arranged along an axis In the pipe
An EGR distribution pipe characterized in that the opening area of each distribution hole is gradually increased in order from the one close to the inlet. A distal end is closed, an inlet for introducing EGR gas is provided at the proximal end, and a plurality of first distribution holes for distributing and leading out the EGR gas are arranged along an axis. Pipes,
Corresponding to each first distribution hole, it is provided on the outer periphery of the first pipe via a gap, and both ends are closed, and the EGR gas introduced into the gap from each first distribution hole is distributed. An EGR distribution pipe, comprising: a second pipe in which a plurality of second distribution holes for leading to the outside are arranged along an axis. 3. The EGR distribution pipe according to claim 2, wherein an opening area of each of the first distribution holes is gradually increased from a position close to the inlet. A first pipe having a distal end blocked, an inlet for introducing EGR gas at a proximal end, and at least one first distribution hole for distributing and deriving the EGR gas;
Corresponding to the first distribution hole, it is provided on the outer periphery of the first pipe via a first gap, both ends are closed, and EGR gas introduced into the first gap from the first distribution hole is distributed. A second pipe having a plurality of second distribution holes arranged along the axis,
EGR gas that is provided on the outer periphery of the second pipe via the second gap corresponding to the second distribution holes, is closed at both ends, and is introduced into the second gap from the second distribution holes. An EGR distribution pipe, comprising: a third pipe having a plurality of third distribution holes arranged along the axis for distributing the liquid to the outside. The sleeve pipe is disposed on the outer periphery of the base end portion through a gap, and the sleeve pipe has one end connected to the base end portion and the other end opened to have a flange. EGR distribution pipe as described. A sleeve pipe is disposed on the outer periphery of the base end portion through a gap, and the sleeve pipe has one end connected to the base end portion and the other end opened to have a flange;
2. The EGR distribution pipe according to claim 1, wherein the distal end portion is closed by caulking, and a through hole that intersects the axis is formed on the distal end side from the caulking position. 3. A sleeve pipe is disposed on the outer periphery of the base end portion through a gap, and the sleeve pipe has one end connected to the base end portion and the other end opened to have a flange;
The distal end portion is closed by caulking, and a through-hole intersecting the axis is formed on the distal end side from the caulking position, and the flange at the base end portion is attached to the wall surface of the intake manifold, The front end side of the caulking position of the front end portion is supported by a wall surface of the intake manifold via a rubber piece, and the distribution holes are arranged corresponding to the inlets of the branch pipes of the intake manifold. Item 2. The EGR distribution pipe according to Item 1. A sleeve pipe is disposed on the outer periphery of the base end portion of the first pipe via a gap, and the sleeve pipe has one end connected to the base end portion and the other end opened to have a flange. The EGR distribution pipe according to any one of claims 2 to 4. A sleeve pipe is disposed on the outer periphery of the base end portion of the first pipe via a gap, and the sleeve pipe has one end connected to the base end portion and the other end opened to have a flange;
The tip of the first pipe is closed by caulking, and a through hole that intersects the axis of the first pipe is formed on the tip side from the caulking position. 5. The EGR distribution pipe according to any one of 4 above. A sleeve pipe is disposed on the outer periphery of the base end portion of the first pipe via a gap, and the sleeve pipe has one end connected to the base end portion and the other end opened to have a flange;
A distal end portion of the first pipe is closed by caulking, and a through-hole intersecting the axis of the first pipe is formed on the distal end side from the caulking position. It is attached to the wall surface of the manifold, the tip side of the caulking position of the tip portion is supported on the wall surface of the intake manifold via a rubber piece, and each of the second distribution holes or each of the third distribution holes is each of the intake manifolds. The EGR distribution pipe according to any one of claims 2 to 4, wherein the EGR distribution pipe is disposed corresponding to an inlet of the branch pipe.

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