JP2009209874A - Intake device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake device for engine, capable of securing sure mixing of intake air with EGR gas, and moreover, which has superior installability. <P>SOLUTION: This intake device for engine comprises a bottomed cylindrical mixing pipe 1 comprising a cylindrical wall 11, to which an intake pipe 2 is connected, and a branch part 4, in which a plurality of branch pipes 5 communicated with each of cylinders are divided, on a downstream side of the mixing pipe 10. Air-fuel mixture of intake air and EGR gas from the intake pipe 2 is led into the mixing pipe 10, from a tangential direction along the inner surface of the cylindrical wall 11 and is mixed by the swirling of the air-fuel mixture formed inside the mixing pipe 10; and thereafter, the air-fuel mixture is divided from the branch part 4 to each of the intake branch pipes 5 and is supplied to each of the cylinders. The mixing pipe 10 is formed with an expansion part 13 which swells continuously, to the cylindrical wall 11 on a side opposite to the branch part 4 relative to an opening 2a of the intake pipe 2, and on a side facing a part of the cylindrical wall 11, in which air-fuel mixture is led, from the intake pipe 2, along the tangent direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine intake device, and more particularly to an engine intake device that mixes EGR gas and intake air and supplies the mixture to each cylinder in an engine that recirculates exhaust gas in an exhaust system as EGR gas to the intake system.

  Conventionally, in an engine, in order to reduce NOx emission, there is a method of reducing the temperature of combustion gas by recirculating a part of exhaust gas in the exhaust system to the intake system as EGR gas. In order to operate this type of engine efficiently, it is necessary to make the mixing ratio of the intake air and the EGR gas uniform among the cylinders, that is, to reduce the variation in the EGR rate.

  For this reason, various techniques have been proposed in which the intake air and the EGR gas are sufficiently mixed in the region upstream of the intake branch pipe connected to each cylinder to obtain an air-fuel mixture having a uniform mixing ratio.

  For example, it is effective to increase the mixing distance between the intake air and the EGR gas by extending the path from the place where the intake air and the EGR gas merge to the intake branch pipe. It is extremely difficult to apply to an engine with limited space.

  Therefore, in Patent Document 1, the upstream pipe and the downstream pipe through which the mixture of the intake air and the EGR gas flows are substantially orthogonal, and the pipe axis of the upstream pipe with respect to the pipe axis of the downstream pipe. The intake air supplied to the surge tank in which the intake branch pipe is provided after the upstream pipe line and the downstream pipe line are connected to each other so as to impart a swirling force to the air-fuel mixture in the downstream pipe line and mix the mixture. A manifold has been proposed.

  Further, in Patent Document 2, a surge tank is provided upstream of a plurality of intake branch pipes provided corresponding to each cylinder, and a mixture of intake air and EGR gas that are cylindrical and introduced tangentially from an intake pipe An engine intake device that includes a swirl flow forming chamber for forming a swirl flow and that houses the swirl flow formation chamber in a surge tank has been proposed.

JP 2001-73882 A JP-A-2005-98152

  According to the intake manifold described in the above-mentioned Patent Document 1, although the swirl force is applied to the mixture of the intake air and the EGR gas in the downstream pipe to achieve mixing, the swirl flow is in its flow direction, that is, the downstream surge. There is a concern that a situation in which the intake air and the EGR gas are not sufficiently mixed due to pulling to the tank side and weakening of the turning force tends to occur.

  Further, according to the engine intake device described in Patent Document 2, the swirl flow forming chamber that forms the swirl flow by the mixture of the intake air introduced from the intake pipe and the EGR gas has a large radial direction and further surges. Since it is housed and formed in the tank, there is a concern that the intake device becomes large and requires a large mounting space, making it difficult to apply to an engine in which the mounting space is restricted.

  Accordingly, an object of the present invention made in view of such points is to provide an engine intake device that can ensure uniform mixing of intake air and EGR gas and is excellent in mountability.

  An engine intake device according to claim 1 that achieves the above object is provided in an engine that recirculates exhaust gas in an exhaust system as EGR gas to the intake system, and a cylinder to which the intake pipe and the intake pipe are connected. A bottomed cylindrical mixing pipe provided with a wall, and a branching portion branched into a plurality of intake branch pipes communicating with each cylinder on the downstream side of the mixing pipe, and intake air and EGR gas from the opening of the intake pipe Is introduced into the mixing pipe in a tangential direction along the inner surface of the cylindrical wall, and the intake air of the air-fuel mixture and the EGR gas are mixed by the swirling flow of the air-fuel mixture formed in the mixing pipe. In the engine intake device in which the air-fuel mixture is distributed from the branch part to the intake branch pipes and supplied to the cylinders, the mixed pipe is provided on the opposite side of the branch part with respect to the opening of the intake pipe. And the tangential direction from the intake pipe Air-fuel mixture, characterized in that the formation of the bottomed extension bulging the conduit axis of the mixing pipe on the side facing the part of the cylindrical wall to be introduced along.

  According to the present invention, a simple configuration in which a bottomed cylindrical expansion portion is formed on the side opposite to the branch portion with respect to the intake pipe connected to the mixture pipe into which the mixture of intake air and EGR gas is introduced from the intake pipe. Thus, a strong swirling flow is formed in the air-fuel mixture flowing in the mixing pipe, and the mixing distance due to the swirling flow of the air-fuel mixture in the mixing pipe increases, resulting in a uniform mixing ratio of intake air and EGR gas, that is, variation in the EGR rate. Reduced.

  In addition, the strong swirling flow increases the speed in the swirling direction and increases the mixing distance with respect to the flow speed from the mixing pipe to the branching direction. The length can be shortened, and the extended portion protruding in the pipe axis direction is partial and the amount of protrusion is small, so that the intake device can be made compact, and the mountability is improved.

  According to a second aspect of the present invention, in the engine intake system of the first aspect, the cylindrical wall of the mixing pipe is cylindrical, and the expansion portion is a cylindrical shape continuous to the cylindrical wall and the tangential direction. The distance in the pipe axial direction from the opening on the opposite side is larger than the distance in the pipe axial direction from the opening on the side of the cylindrical wall where the air-fuel mixture is introduced along It is characterized in that it is formed by a peripheral wall having an edge that is inclined with respect to the pipe axis, and a bottom wall that closes the edge of the peripheral wall.

  According to the present invention, a compact extension portion is formed in which a mixture pipe having a cylindrical tube wall is shifted from the side of the tube wall where the air-fuel mixture is introduced along the tangential direction to the opposite side, so that the capacity gradually increases. Is done.

  According to a third aspect of the present invention, in the engine intake device of the first aspect, the cylindrical wall of the mixing pipe is cylindrical, and the extension portion is a cylindrical shape continuous to the cylindrical wall and the tangential direction. A portion of the cylindrical wall into which the air-fuel mixture is introduced is positioned at the opening in the direction of the pipe axis and is spaced from the opening on the opposite side by a predetermined distance in the direction of the pipe axis with respect to the pipe axis. And a bottom wall that closes the edge of the peripheral wall.

  According to the present invention, the compact extension portion in which the capacity gradually increases as the transition from the portion side of the cylindrical wall into which the air-fuel mixture is introduced along the tangential direction to the opposite side is performed on the mixing pipe having the cylindrical cylindrical wall. It is formed.

  According to a fourth aspect of the present invention, in the engine intake system of the first aspect, the cylindrical wall of the mixing pipe is cylindrical, and the extension portion is a cylindrical shape continuous to the cylindrical wall and the tangential direction. A circumferential wall having a substantially semicircular cross section formed continuously from the cylindrical wall on the side of the cylindrical wall where the air-fuel mixture is introduced along the cylindrical wall, and between the both side edges of the circumferential wall and the cylinder It is characterized by being formed by a bottom wall that closes between the walls.

  According to the present invention, a compact extension portion is formed along the cylindrical wall on the side opposite to the side of the cylindrical wall where the air-fuel mixture is introduced along the tangential direction in the mixing pipe having the cylindrical cylindrical wall. .

  According to a fifth aspect of the present invention, in the engine intake system of the first aspect, the cylinder wall of the mixing pipe has a substantially rectangular cross-sectional shape including a first side wall, a second side wall, a third side wall, and a fourth side wall. A cylindrical shape continuous in the pipe axis direction, and the intake pipe opens to the first side wall so that the air-fuel mixture is introduced along the tangential direction of the inner surface of the second side wall. A cross-sectional rectangle having a first side portion, a second side portion, a third side portion, and a fourth side portion continuous with the side wall, the second side wall, the third side wall, and the fourth side wall, respectively, and extending in the pipe axis direction And a peripheral wall having an edge inclined with respect to the pipe axis so as to gradually move away from the opening in the pipe axis direction as it moves from the second side to the fourth side, and an edge of the peripheral wall It is formed by the bottom wall which obstruct | occludes.

  According to this invention, the first side wall, the second side wall, the third side wall, and the fourth side wall are connected in a tangential direction to the mixing pipe having a cylindrical wall that is continuous in the pipe axis direction with a substantially rectangular cross-sectional shape. A compact extension portion is formed in which the capacity gradually increases as the air-fuel mixture is introduced from the second side wall side to the opposing fourth side wall side.

  According to a sixth aspect of the present invention, in the engine intake system of the first aspect, the cylindrical wall of the mixing pipe has a substantially rectangular cross-sectional shape including a first side wall, a second side wall, a third side wall, and a fourth side wall. A cylindrical shape continuous in the pipe axis direction, and the intake pipe opens to the first side wall so that the air-fuel mixture is introduced along the tangential direction of the inner surface of the second side wall. The second side wall has a first side part, a third side part, and a fourth side part that are continuous with the third side wall and the fourth side wall, respectively, and has a U-shaped cross section extending in the pipe axis direction. A peripheral wall having an edge inclined with respect to the pipe axis so as to gradually move away from the opening in the pipe axis direction as it moves from the first side to the fourth side, and a bottom closing the first side wall and the edge of the peripheral wall It is characterized by being formed by walls.

  According to this invention, the first side wall, the second side wall, the third side wall, and the fourth side wall are connected in a tangential direction to the mixing pipe having a cylindrical wall that is continuous in the pipe axis direction with a substantially rectangular cross-sectional shape. A compact expansion portion is formed in which the capacity gradually increases as the air-fuel mixture is introduced from the first side wall side to the opposing fourth side wall side.

  According to a seventh aspect of the present invention, in the engine intake system of the first aspect, the cylindrical wall of the mixing pipe has a substantially rectangular cross-sectional shape including a first side wall, a second side wall, a third side wall, and a fourth side wall. A cylindrical shape continuous in the pipe axis direction, and the intake pipe opens to the first side wall so that the air-fuel mixture is introduced along the tangential direction of the inner surface of the second side wall. The first side portion, the third side portion, and the fourth side portion are continuously formed in the range set on the fourth side wall side, the third side wall, and the range set on the fourth side wall side of the third side wall. It is characterized in that it is formed by a peripheral wall having a substantially U-shaped cross section and a bottom wall that closes between the edge of the peripheral wall, both side edges of the peripheral wall, and between the cylindrical walls.

  According to this invention, the first side wall, the second side wall, the third side wall, and the fourth side wall are connected in a tangential direction to the mixing pipe having a cylindrical wall that is continuous in the pipe axis direction with a substantially rectangular cross-sectional shape. An extension portion is formed along the fourth side wall facing the first side wall into which the air-fuel mixture is introduced.

  According to the present invention, a simple configuration in which a bottomed cylindrical expansion portion is formed on the side opposite to the branch portion with respect to the intake pipe connected to the mixture pipe into which the mixture of intake air and EGR gas is introduced from the intake pipe. Thus, a strong swirl flow is formed in the air-fuel mixture flowing in the mixing pipe, and uniform mixing of the intake air and the EGR gas is obtained.

  In addition, the mixing pipe serving as the mixing section of the air-fuel mixture can be shortened, and the extended portion protruding in the pipe axis direction is local and has a small protruding amount, so that the mounting capability of the intake device is improved.

  An embodiment of an engine intake device according to the present invention will be described with reference to the drawings.

(First embodiment)
The first embodiment will be described with reference to FIGS.

  FIG. 1 shows an intake system for an engine according to the present embodiment. Reference numeral 1 denotes an intake manifold for the engine. The intake manifold 1 includes an intake pipe 2 in which a slot valve is disposed upstream to introduce intake air, an EGR pipe 3 that is connected to the intake pipe 2 and introduces EGR gas into the intake pipe 2, and an intake pipe 2. A bottomed cylindrical mixing pipe 10 for mixing the introduced intake air and EGR gas, and a branch section 4 connected to the downstream side of the mixing pipe 10 and branching to a plurality of intake branch pipes 5 communicating with each cylinder. It is integrally formed continuously.

  2 is a perspective view of a main portion of the intake manifold 1 shown in FIG. 2, FIG. 3 schematically shows the mixing pipe 10, FIG. 4 shows a cross section taken along line II in FIG. 3, and II-II in FIG. 3. The mixing pipe 10 will be described with reference to FIG.

  The mixing pipe 10 includes a substantially cylindrical tube wall 11, the downstream side is continuous with the branching section 4, and the mixing pipe 10 is moved to the upstream side by a predetermined dimension in the direction of the pipe axis 10 </ b> L of the mixing pipe 10 from the branching section 4. A smaller-diameter intake pipe 2 is connected. The intake pipe 2 and the mixing pipe 10 are orthogonal to each other, and the pipe axis 2L of the intake pipe 2 is offset from the pipe axis 10L of the mixing pipe 10 so that the opening 2a of the intake pipe 2 is a cylinder of the mixing pipe 10. Connected to the inner surface of the wall 11 in a tangential direction. As a result, a swirl force is applied to the air-fuel mixture introduced from the air intake pipe 2 between the air intake pipe 2 and the branching portion 4, and a cylindrical mixing chamber 12 that forms a swirl flow caused by the air-fuel mixture is formed.

  Further, the mixing pipe 10 faces the portion of the cylindrical wall 11 where the air-fuel mixture is introduced from the intake pipe 2 along the tangential direction on the side opposite to the branch portion with respect to the opening 2a of the intake pipe 2. On the side, a bottomed extended portion 13 is formed which is continuous with the cylindrical wall 11 and bulges in the direction of the pipe axis 10L of the mixing pipe 10.

  As shown in FIGS. 3 and 5, the peripheral wall 14 forming the expanded portion 13 is cylindrical, and the intake pipe 2 on the side of the cylindrical wall 11 into which the air-fuel mixture is introduced from the intake pipe 2 along the tangential direction. From the opening 2a on the side facing the portion of the cylindrical wall 11 where the air-fuel mixture is introduced from the intake pipe 2 along the tangential direction with respect to the distance a in the direction of the pipe axis 10L from the opening 2a to the end edge 14a The end edge 14a is inclined with respect to the pipe axis 10L so that the distance b in the direction of the pipe axis 10L to the end edge 14a is increased.

  The bottom wall 15 that closes the end edge 14a of the peripheral wall 14 is disposed to be inclined with respect to the pipe axis 10L. The expansion portion 13 formed by the peripheral wall 14 and the bottom wall 15 shifts from the portion side of the cylindrical wall 11 where the air-fuel mixture is introduced from the intake pipe line 2 along the tangential direction to the side facing the portion. Therefore, the capacity gradually increases. An increasing bottomed cylindrical swirl flow forming chamber 16 is formed.

  According to the intake manifold 1 configured as described above, EGR gas is introduced from the EGR pipe 3 into the intake pipe 2 through which intake air is introduced, and a mixture of intake air and EGR gas is introduced from the opening 2 a of the intake pipe 2. It is introduced into the mixing chamber 12 along the tangential direction of the cylindrical wall 11 of the mixing pipe 10.

  The air-fuel mixture introduced from the intake pipe 2 into the mixing chamber 12 is given a turning force along the inner surface of the cylinder wall 11, and a part of the mixture turns along the inner surface of the cylinder wall 11 as shown by an arrow A in FIG. However, the main flow that flows toward the branching portion 4 is promoted to mix the intake air and the EGR gas.

  On the other hand, a part of the air-fuel mixture introduced from the intake pipe 2 into the mixing chamber 12 is divided into the main flow A, and a swirl force along the inner surface of the cylindrical wall 11 is applied to the swirl flow forming chamber 16 as indicated by an arrow B. A swirl force along the inner surface of the peripheral wall 14 is applied to swirl the swirl flow forming chamber 16 along the peripheral wall 14 and the bottom surface 15 to promote mixing of the intake air and the EGR gas.

  Further, the air-fuel mixture swirled in the swirling flow molding chamber 16 flows toward the mixing chamber 12 while swirling, and joins the main flow A flowing in the mixing chamber 12 to form a strong swirling flow C together with the main flow A. Due to this strong swirl flow C, the swirl speed becomes higher than the flow speed in the direction of the branching section 4, and the mixing distance by the swirl of the air-fuel mixture in the mixing chamber 12 increases, so that the intake air and EGR gas are uniformly mixed. The variation of the ratio, that is, the EGR rate is reduced.

  The air-fuel mixture, which is sufficiently mixed in the mixing chamber 12 and uniformly mixed with intake air and EGR gas, is distributed to the intake branch pipes 5 in the branch portions 4 disposed downstream of the mixing chamber 12 to be used for the cylinders. To be supplied.

  Therefore, according to the present embodiment configured as described above, the bottomed cylinder having the peripheral wall 14 and the bottom wall 15 on the opposite side of the branch portion 4 with respect to the opening 2a of the intake pipe 2 connected to the mixing pipe 10. A simple swirling flow is formed in the mixture flowing in the mixing pipe 10 with a simple configuration that forms the expanded portion 13, the mixing distance due to the swirling flow is increased, and a uniform mixing ratio of intake air and EGR gas, that is, The variation in EGR rate is reduced.

  In addition, the flow from the inside of the mixing pipe 10 toward the branch portion 4 is suppressed, and the length of the mixing pipe 10 in the direction of the pipe axis 10L, which becomes the mixture section of the air-fuel mixture, can be shortened, and the pipe axis 10L. The extending portion 13 protruding in the direction is local and compact and has a small protruding amount, so that the intake manifold 1 can be made compact and mountability is improved.

It should be noted that the shape and size of the expansion portion 13 can be easily set in advance by experiments, simulations, or the like. As a result of the experiment, the volume in the expansion part 13, that is, the volume V of the swirl flow forming chamber 16 is V> 0.5 × (D / 2) ² × π × 0. 15
In other words, a good uniform mixing ratio of intake air and EGR gas could be confirmed when the mixing pipe 10 had an inner diameter D and a volume of more than half of a cylinder having a height of 0.15D.

(Second Embodiment)
A second embodiment will be described with reference to FIGS.

  The present embodiment is different from the first embodiment in the shape of the extended portion formed in the mixing pipe, and other configurations are the same as those in the first embodiment, and the mixing pipe will be mainly described. For convenience of explanation, in FIGS. 6 to 8, parts corresponding to those in FIGS. 1 to 5 are denoted by the same reference numerals.

  6 is a diagram schematically showing the mixing pipe 10 in the present embodiment, FIG. 7 is a sectional view taken along line III-III in FIG. 6, and FIG. 8 is a sectional view taken along line IV-IV in FIG.

  The mixing pipe 10 is provided with a cylindrical wall 11, the downstream side is continuous with the branch portion 4, and the intake pipe 2 is connected to a position that has shifted from the branch portion 4 to the upstream side by a predetermined dimension. The intake pipe 2 and the mixing pipe 10 are substantially orthogonal to each other, and the pipe axis 2L of the intake pipe 2 is offset from the pipe axis 10L of the mixing pipe 10 so that the opening 2a of the intake pipe 2 is a cylinder of the mixing pipe 10. Connected to the wall 11 in a tangential direction. As a result, a mixing chamber 12 is formed between the intake pipe 2 and the branch portion 4 to form a swirl flow by the air-fuel mixture introduced from the intake pipe 2.

  Further, the mixing pipe 10 has a side opposite to the branch part 4 with respect to the opening 2a of the intake pipe 2 and a side facing the portion of the cylindrical wall 11 into which the air-fuel mixture is introduced from the intake pipe 2 along the tangential direction. In addition, a bottomed extended portion 13 including a peripheral wall 14 and a bottom wall 15 bulging in the direction of the pipe axis 10 </ b> L of the mixing pipe 10 is formed continuously with the cylindrical wall 11.

  As shown in FIGS. 6 and 8, the peripheral wall 14 has a cylindrical shape that is continuous with the cylindrical wall 11, and a portion of the cylindrical wall 11 into which the air-fuel mixture is introduced along the tangential direction has an opening 2 a in the direction of the pipe axis 10 </ b> L. On the other hand, it has an edge 14a that is inclined with respect to the pipe axis 10L so as to be separated by a predetermined distance in the direction of the pipe axis 10L from the opening 2a on the opposite side. The bottom wall 15 that closes the end edge 14a of the peripheral wall 14 is disposed to be inclined with respect to the pipe axis 10L. The expansion portion 13 formed by the peripheral wall 14 and the bottom wall 15 shifts from the side of the cylindrical wall 11 where the air-fuel mixture is introduced from the intake pipe 2 along the tangential direction to the side opposite to the side, so that the capacity gradually increases. Thus, a bottomed cylindrical swirl flow forming chamber 16 that forms a swirl flow by the air-fuel mixture introduced from the intake pipe 2 is formed.

  According to the intake manifold 1 configured as described above, an air-fuel mixture of intake air and EGR gas is introduced into the mixing chamber 12 from the opening 2 a of the intake pipe 2 along the tangential direction of the cylindrical wall 11 of the mixing pipe 10. . The air-fuel mixture introduced from the intake pipe 2 into the mixing chamber 12 is given a turning force along the inner surface of the cylinder wall 11, and a part of the mixture turns along the inner surface of the cylinder wall 11 as shown by an arrow A in FIG. However, it flows to the branch part 4 side and mixing is promoted.

  On the other hand, a part of the air-fuel mixture introduced from the intake pipe 2 into the mixing chamber 13 is divided into the main flow A and is given a turning force along the inner surface of the cylindrical wall 11 so that the swirling flow forming chamber 16 is indicated by an arrow B. A swirl force along the inner surface of the peripheral wall 14 is applied to swirl the swirl flow forming chamber 16 along the peripheral wall 14 and the bottom surface 15 to promote mixing.

  Further, the air-fuel mixture swirled in the swirling flow molding chamber 16 flows along the peripheral wall 14 and the bottom wall 15 to the mixing chamber 12 side, merges with the main flow A flowing in the mixing chamber 12, and is strong together with the main flow A. A swirling flow C is formed. This strong swirling flow C suppresses the flow of the air-fuel mixture in the direction of the branching portion 4 and increases the mixing distance due to the swirling flow in the mixing chamber 12, thereby promoting uniform mixing of intake air and EGR gas.

  An air-fuel mixture in which intake air and EGR gas are uniformly mixed in the mixing chamber 12 is distributed to the intake branch pipes 5 from the branch portions 4 disposed downstream of the mixing chamber 12 and supplied to the cylinders.

  Therefore, according to the present embodiment configured as described above, the bottomed cylinder having the peripheral wall 14 and the bottom wall 15 on the opposite side of the branch portion 4 with respect to the opening 2a of the intake pipe 2 connected to the mixing pipe 10. A uniform configuration of the expanded portion 13 can be obtained by uniformly mixing the intake air and the EGR gas.

  In addition, the length of the mixing pipe 10 in the direction of the pipe axis 10 of the mixing pipe 10 serving as the mixture section of the air-fuel mixture can be shortened, and the extension part 13 protruding in the direction of the pipe axis 10L is local and compact, and the protruding amount is large. Smaller, the intake manifold 1 can be made more compact, and the mountability is improved.

Note that the shape and size of the expansion portion 13 can be easily set in advance by experiments, simulations, or the like. As a result of the experiment, the volume in the expansion part 13, that is, the volume V of the swirl flow forming chamber 16 is V> 0.5 × (D / 2) ² × π × 0. 15
In other words, a good uniform mixing ratio of intake air and EGR gas could be confirmed when the mixing pipe 10 had an inner diameter D and a volume of more than half of a cylinder having a height of 0.15D.

(Third embodiment)
A third embodiment will be described with reference to FIGS.

  The present embodiment is different from the first embodiment in the shape of the extended portion formed in the mixing pipe, and other configurations are the same as those in the first embodiment, and the mixing pipe will be mainly described. For convenience of explanation, in FIGS. 9 to 11, parts corresponding to those in FIGS. 1 to 5 are denoted by the same reference numerals.

  9 is a diagram schematically showing the mixing pipe 10 in the present embodiment, FIG. 10 is a cross-sectional view taken along line VV in FIG. 9, and FIG. 11 is a cross-sectional view taken along line VI-VI in FIG.

  The mixing pipe 10 includes a cylindrical wall 11, the downstream side is continuous with the branch portion 4, the intake pipe 2 is substantially orthogonal to the upstream side of the branch portion 4 by a predetermined dimension, and with respect to the pipe axis 10 </ b> L of the mixing pipe 10. As a result, the pipe shaft 2L of the intake pipe 2 is offset, and the opening 2a of the intake pipe 2 is connected to the cylindrical wall 11 of the mixing pipe 10 in the tangential direction. As a result, a cylindrical mixing chamber 12 is formed between the intake pipe 2 and the branch portion 4.

  Furthermore, the mixing pipe 10 has a side opposite to the branching portion with respect to the opening 2a of the intake pipe 2 and a side facing the portion of the cylindrical wall 11 into which the air-fuel mixture is introduced from the intake pipe 2 along the tangential direction. A bottomed extended portion 13 bulging in the direction of the pipe axis 10 </ b> L of the mixing pipe 10 is formed continuously with the cylindrical wall 11.

  As shown in FIGS. 9 and 11, the extended portion 13 has a cross-sectional view that continuously protrudes from the cylindrical wall 11 on the side facing the portion of the cylindrical wall 11 where the air-fuel mixture is introduced from the intake pipe 2 along the tangential direction. A semicircular arc-shaped peripheral wall 14, and a bottom wall 15 that closes between the side walls 14 b of the peripheral wall 14 and between the cylindrical walls 11 from the end edge 14 a side of the peripheral wall 14, and an extension 13 formed by the peripheral wall 14 and the bottom wall 15. Thus, a swirl flow forming chamber 16 is formed along the cylindrical wall 11 on the side facing the portion of the cylindrical wall 11 where the air-fuel mixture is introduced from the intake pipe 2 along the tangential direction.

  According to the intake manifold 1 configured as described above, an air-fuel mixture of intake air and EGR gas is introduced into the mixing chamber 12 from the opening 2 a of the intake pipe 2 along the tangential direction of the cylindrical wall 11 of the mixing pipe 10. . The air-fuel mixture introduced from the intake pipe 2 into the mixing chamber 12 is given a turning force along the inner surface of the cylinder wall 11, and a part of the mixture turns along the inner surface of the cylinder wall 11 as shown by an arrow A in FIG. However, it becomes the mainstream which flows to the branch part 4 side, and promotes mixing.

  On the other hand, a part of the air-fuel mixture introduced from the intake pipe 2 into the mixing chamber 12 is divided into the main flow A and is given a turning force along the inner surface of the cylindrical wall 11 so that the swirling flow forming chamber 16 is indicated by an arrow B. The inside turns along the peripheral wall 14 and the bottom surface 15.

  Further, the air-fuel mixture swirled in the swirling flow molding chamber 16 is guided to the peripheral wall 14 and the bottom wall 15 and flows to the mixing chamber 12 side, and merges with the main flow A flowing in the mixing chamber 12 to form a strong swirling flow C. . This strong swirling flow C suppresses the flow in the direction of the branching section 4 to secure a mixing distance by the swirling flow in the mixing chamber 12, and uniform mixing of intake air and EGR gas is obtained. The air-fuel mixture in which the intake air and the EGR gas are uniformly mixed is branched into the intake branch pipes 5 at the branch portions 4 and supplied to the cylinders.

  Therefore, according to the present embodiment configured as described above, the peripheral wall 14 and the bottom wall 15 are provided on the opposite side of the branch portion 4 from the opening 2a of the intake pipe 2 of the mixing pipe 10 as in the first embodiment. Uniform mixing of intake air and EGR gas can be obtained with a simple configuration that forms the bottomed expansion portion 13.

  Further, since the flow from the inside of the mixing pipe 10 toward the branching section 4 is suppressed, the length of the mixing pipe 10 serving as the mixing section of the air-fuel mixture in the direction of the pipe axis 10L can be shortened, and the pipe line The expansion portion 13 projecting in the direction of the shaft 10L is local and compact, and the mountability of the intake manifold 1 is improved.

It should be noted that the shape and size of the expansion portion 13 can be easily set in advance by experiments, simulations, or the like. As a result of the experiment, the volume in the expansion part 13, that is, the volume V of the swirl flow forming chamber 16 is V> 0.5 × (D / 2) ² × π × 0. 15
In other words, a good uniform mixing ratio of intake air and EGR gas could be confirmed when the mixing pipe 10 had an inner diameter D and a volume of more than half of a cylinder having a height of 0.15D.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIGS.

  In this embodiment, the shape of the mixing pipe is different from that of the first embodiment. Other configurations are the same as those of the first embodiment, and the mixing pipe will be mainly described. For convenience of explanation, portions in FIGS. 12 to 14 corresponding to those in FIGS. 1 to 5 are denoted by the same reference numerals.

  12 is a diagram schematically showing the mixing pipe 10 in the present embodiment, FIG. 13 is a sectional view taken along line VII-VII in FIG. 12, and FIG. 14 is a sectional view taken along line VIII-VIII in FIG.

  The mixing pipe 10 includes a cylindrical wall 11 having a substantially rectangular cross section in which the first side wall 11A, the second side wall 11B, the third side wall 11C, and the fourth side wall 11D are sequentially continuous in the circumferential direction, and the downstream side is continuous with the branch portion 4. . The intake pipe 2 is connected to a position shifted from the branch part 4 in the first side wall 11A to the upstream side by a predetermined dimension in the direction of the pipe axis 10L of the mixing pipe 10. The intake pipe 2 and the mixing pipe 10 are substantially orthogonal to each other, and the pipe axis 2L of the intake pipe 2 is offset with respect to the pipe axis 10L of the mixing pipe 10 so that the opening 2a of the intake pipe 2 is the second of the mixing pipe 10. It is connected to the side wall 11B in a tangential direction. As a result, a mixing chamber 12 having a rectangular cross section is formed between the intake pipe 2 and the branch portion 4 to form a swirling flow caused by the air-fuel mixture introduced from the intake pipe 2.

  Further, the mixing pipe 10 faces the second side wall 11B of the cylindrical wall 11 on the side opposite to the branching section 4 with respect to the opening 2a of the intake pipe 2 and into which the air-fuel mixture is introduced from the intake pipe 2 in the tangential direction. An extended portion 13 is formed on the fourth side wall 11D side by the peripheral wall 14 and the bottom wall 15 that bulge in the direction of the pipe axis 10L along the fourth side wall 11D.

  As shown in FIGS. 12 and 14, the peripheral wall 14 includes a first side portion 14A, a second side portion 14B, and a third side portion that are continuous with the first side wall 11A, the second side wall 11B, the third side wall 11C, and the fourth side wall 11D, respectively. The side portion 14C and the fourth side portion 14D are formed in a substantially rectangular cross section. The edge 14a of the peripheral wall 14 is inclined with respect to the pipe axis 10L so that the distance from the opening 2a is larger on the fourth side wall 11D side than on the second side wall 11B side edge. . The bottom wall 15 is inclined with respect to the pipe axis 10L so as to close the end edge 14a of the peripheral wall 14.

  Thus, the swirl flow in which the capacity gradually increases as the expansion portion 13 formed by the peripheral wall 14 and the bottom wall 15 shifts from the second side wall 11B side where the air-fuel mixture is introduced in the tangential direction to the opposing fourth side wall 11D side. A forming chamber 16 is formed.

  According to the intake manifold 1 configured as described above, a mixture of intake air and EGR gas is introduced into the mixing chamber 12 from the opening 2a of the intake pipe 2 along the second side wall 11B of the mixing pipe 10.

  The air-fuel mixture introduced from the intake pipe 2 along the second side wall 11B of the mixing chamber 13 is given a swirl force that flows along the inner surfaces of the third side wall 11C, the fourth side wall 11D, and the first side wall 11A. As shown by an arrow A in FIG. 12, the portion turns along the inner surface of the cylindrical wall 11 and becomes a main flow that flows toward the branching portion 4 to promote mixing.

  On the other hand, a part of the air-fuel mixture introduced from the intake pipe 2 into the mixing chamber 12 is divided into the main flow A and, as indicated by an arrow B, the second side portion 14B, the third side portion 14C of the swirl flow forming chamber 16; A turning force along each inner surface of the fourth side portion 14 </ b> D and the first side portion 14 </ b> A is applied, and the inside of the swirling flow molding chamber 16 is swung along the peripheral wall 14 and the bottom surface 15.

  Further, the air-fuel mixture swirled in the swirl flow molding chamber 16 flows toward the mixing chamber 12 and joins with the main flow A flowing in the mixing chamber 13 to form a strong swirl flow C together with the main flow A. This strong swirling flow C suppresses the flow in the direction of the branching portion 4 and increases the mixing distance of the air-fuel mixture in the mixing chamber 12 due to the swirling flow, thereby obtaining uniform mixing of the intake air and the EGR gas. The air-fuel mixture in which the intake air and EGR gas are uniformly mixed is distributed from the branch portion 4 to each intake branch pipe 5 and supplied to each cylinder.

  Therefore, according to the present embodiment configured as described above, the opening 2a of the intake pipe 2 in the mixed pipe 10 into which the mixture of the intake air and the EGR gas is introduced from the intake pipe 2 is located on the opposite side to the branch section 4. Intake air and EGR with a simple configuration that forms the bottomed cylindrical expansion portion 13 by the peripheral wall 14 and the bottom wall 15 of the first side portion 14A, the second side portion 14B, the third side portion 14C, and the fourth side portion 14D. A homogeneous mixing of the gas is obtained.

  Further, since the flow from the inside of the mixing pipe 10 toward the branching section 4 is suppressed, the length of the mixing pipe 10 serving as the mixing section of the air-fuel mixture in the direction of the pipe axis 10L can be shortened, and the pipe line The expansion portion 13 projecting in the direction of the shaft 10L is local and compact, and the mountability of the intake manifold 1 is improved.

Note that the shape and size of the expansion portion 13 can be easily set in advance by experiments, simulations, or the like. As a result of the experiment, the volume V in the expansion part 13, that is, the volume V of the swirl flow forming chamber 16 is V> 0. 5 × (D / 2) ² × π × 0.15
That is, a good uniform mixing ratio of intake air and EGR gas could be confirmed at a volume larger than a half of a circular cylinder having a diameter D and a height of 0.15D equivalent to the cross-sectional area of the mixing pipe 10. .

(Fifth embodiment)
A fifth embodiment will be described with reference to FIGS. 15 to 17.

  The present embodiment is different from the fourth embodiment in the shape of the extended portion formed in the mixing pipe, the other configuration is the same as that of the fifth embodiment, and the mixing pipe will be mainly described. For convenience of explanation, in FIGS. 15 to 17, portions corresponding to FIGS. 12 to 14 are denoted by the same reference numerals.

  15 is a diagram schematically showing the mixing pipe 10 in the present embodiment, FIG. 16 is a sectional view taken along line IX-IX in FIG. 15, and FIG. 17 is a sectional view taken along line XX in FIG.

  The mixing pipe 10 includes a cylindrical wall 11 having a substantially rectangular cross section in which the first side wall 11A, the second side wall 11B, the third side wall 11C, and the fourth side wall 11D are sequentially continuous in the circumferential direction, and the downstream side is continuous with the branch portion 4. . The intake pipe 2 is connected to a position shifted from the branch part 4 in the first side wall 11A to the upstream side by a predetermined dimension in the direction of the pipe axis 10L of the mixing pipe 10. The intake pipe 2 and the mixing pipe 10 are substantially orthogonal to each other, and the pipe axis 2L of the intake pipe 2 is offset with respect to the pipe axis 10L of the mixing pipe 10 so that the opening 2a of the intake pipe 2 is the second of the mixing pipe 10. It is connected to the side wall 11B in a tangential direction. As a result, a mixing chamber 12 is formed between the intake pipe 2 and the branch portion 4 to form a swirling flow by the air-fuel mixture introduced from the intake pipe 2.

  Further, the mixing pipe 10 is opposed to the second side wall 11B of the cylindrical wall 11 into which the air-fuel mixture is introduced in the tangential direction from the intake pipe 2 on the side opposite to the branch portion 4 with respect to the opening 2a of the intake pipe 2. The extended portion 13 is formed by the peripheral wall 14 and the bottom wall 15 that bulge in the direction of the pipe axis 10L along the fourth side wall 11D on the fourth side wall 11D side.

  As shown in FIGS. 15 and 17, the peripheral wall 14 includes a first side portion 14A, a third side portion 14C, and a fourth side portion 14D that are continuous with the first side wall 11A, the third side wall 11C, and the fourth side wall 11D, respectively. It has a substantially U-shaped cross section, and is a substantially triangular shape that separates from the opening 2a in the direction of the pipe axis 10L as the edges of the first side portion 14A and the third side portion 14C move to the fourth side portion 14D side, The four side portions 14D are formed in a substantially rectangular shape. The bottom wall 15 is disposed to be inclined with respect to the pipe axis 10L so as to close the end edge of the second side wall 11B and the end edge 14a of the peripheral wall 14.

  Thus, the swirl flow in which the capacity gradually increases as the expansion portion 13 formed by the peripheral wall 14 and the bottom wall 15 shifts from the second side wall 11B side where the air-fuel mixture is introduced in the tangential direction to the opposing fourth side wall 11D side. A forming chamber 16 is formed.

  According to the intake manifold 1 configured as described above, EGR gas is introduced from the EGR pipe 3 into the intake pipe 2 through which intake air is introduced, and a mixture of intake air and EGR gas is introduced from the opening 2 a of the intake pipe 2. It is introduced into the mixing chamber 13 along the second side wall 11B of the mixing pipe 10.

  The air-fuel mixture introduced from the intake pipe 2 along the second side wall 11B of the mixing chamber 13 is given a swirl force that flows along the inner surfaces of the third side wall 11C, the fourth side wall 11D, and the first side wall 11A. A part of the gas flows along the inner surface of the cylindrical wall 11 as indicated by an arrow A in FIG.

  On the other hand, a part of the air-fuel mixture introduced from the intake pipe 2 into the mixing chamber 12 is divided into the main flow A, and the third side portion 14C, the fourth side portion 14D, A swirl force that flows along each inner surface of the first side portion 14 </ b> A is applied and swirls in the swirl flow molding chamber 16 along the peripheral wall 14 and the bottom surface 15.

  Further, the air-fuel mixture swirled in the swirl flow molding chamber 16 flows toward the mixing chamber 12 and joins with the main flow A flowing in the mixing chamber 13 to form a strong swirl flow C together with the main flow A. The strong swirl flow C increases the mixing distance due to the swirl of the air-fuel mixture in the mixing chamber 12 and promotes uniform mixing of the intake air and the EGR gas. The air-fuel mixture in which the intake air and the EGR gas are uniformly mixed is distributed to the intake branch pipes 5 in the branch portion 4 and supplied to the cylinders.

  Therefore, according to the present embodiment, the peripheral wall 14 and the bottom wall on the opposite side of the branch portion 4 from the joint portion 10a of the intake pipe 2 to the intake pipe 2 into which the mixture of intake air and EGR gas is introduced from the intake pipe 2. With the simple configuration of forming the bottomed cylindrical extension 13 having 15, uniform mixing of intake air and EGR gas can be obtained.

  In addition, the flow from the inside of the mixing pipe 10 toward the branch portion 4 is suppressed, and the length of the mixing pipe 10 in the direction of the pipe axis 10L, which becomes the mixture section of the air-fuel mixture, can be shortened, and the pipe axis 10L. The extending portion 13 protruding in the direction is local and compact, and the mountability of the intake manifold 1 is improved.

It should be noted that the shape and size of the expansion portion 13 can be easily set in advance by experiments, simulations, or the like. As a result of the experiment, the volume V in the expansion part 13, that is, the volume V of the swirl flow forming chamber 16 is V> 0. 5 × (D / 2) ² × π × 0.15
That is, a good uniform mixing ratio of intake air and EGR gas could be confirmed at a volume larger than a half of a circular cylinder having a diameter D and a height of 0.15D equivalent to the cross-sectional area of the mixing pipe 10. .

(Sixth embodiment)
A fifth embodiment will be described with reference to FIGS.

  The present embodiment is different from the fourth embodiment in the shape of the extended portion formed in the mixing pipe, and other configurations are the same as those in the fourth embodiment, and the mixing pipe will be mainly described. For convenience of explanation, in FIGS. 18 to 20, the same reference numerals are given to the portions corresponding to FIGS. 12 to 14.

  18 is a diagram schematically showing the mixing pipe 10 in the present embodiment, FIG. 19 is a cross-sectional view taken along the line XI-XI in FIG. 18, and FIG. 17 is a cross-sectional view taken along the line XII-XII in FIG.

  The mixing pipe 10 includes a cylindrical wall 11 having a substantially rectangular cross section in which the first side wall 11A, the second side wall 11B, the third side wall 11C, and the fourth side wall 11D are sequentially continuous in the circumferential direction, and the downstream side is continuous with the branch portion 4. . The intake pipe 2 is connected to a position shifted from the branch part 4 in the first side wall 11A to the upstream side by a predetermined dimension in the direction of the pipe axis 10L of the mixing pipe 10. The intake pipe 2 and the mixing pipe 10 are substantially orthogonal to each other, and the pipe axis 2L of the intake pipe 2 is offset with respect to the pipe axis 10L of the mixing pipe 10 so that the opening 2a of the intake pipe 2 is the second of the mixing pipe 10. It is connected to the side wall 11B in a tangential direction. As a result, a mixing chamber 12 having a rectangular cross section is formed between the intake pipe 2 and the branch portion 4 to form a swirling flow caused by the air-fuel mixture introduced from the intake pipe 2.

  Further, the mixing pipe 10 is opposed to the second side wall 11B of the cylindrical wall 11 into which the air-fuel mixture is introduced in the tangential direction from the intake pipe 2 on the side opposite to the branch portion 4 with respect to the opening 2a of the intake pipe 2. The extended portion 13 formed by the peripheral wall 14 and the bottom wall 15 bulging in the direction of the pipe axis 10L along the fourth side wall 11D is continuously formed on the fourth side wall 11D side.

  As shown in FIGS. 18 and 20, the peripheral wall 14 has a preset range on the fourth side wall 11D side of the first side wall 11A, a third side wall 11C, and a fourth side wall 11D of the third side wall 11C. A rectangular first side portion 14A, a third side portion 14C, and a fourth side portion 14D that are continuous in the range are formed in a substantially U-shaped cross section. A bottom wall 15 that closes between the end 14a of the peripheral wall 14 and both side edges 14b of the peripheral wall 14 and between the cylindrical walls 11 is provided. As a result, the swirling flow forming chamber 16 that swells in the direction of the pipe axis 10L along the fourth side wall 14D side is formed by the extended portion 13 formed by the peripheral wall 14 and the bottom wall 15.

  According to the intake manifold 1 configured as described above, an air-fuel mixture of intake air and EGR gas is introduced into the mixing chamber 13 along the second side wall 11B of the mixing pipe 10 from the opening 2a of the intake pipe 2.

  The air-fuel mixture introduced from the intake pipe 2 along the second side wall 11B of the mixing chamber 12 is given a swirl force that flows along the inner surfaces of the third side wall 11C, the fourth side wall 11D, and the first side wall 11A. As shown by an arrow A in FIG. 15, the portion becomes a main flow that flows toward the branching portion 4 while turning along the inner surface of the cylindrical wall 11 and promotes mixing of the intake air and the EGR gas.

  On the other hand, a part of the air-fuel mixture introduced from the intake pipe 2 into the mixing chamber 12 is divided into the main flow A, and the third side portion 14C, the fourth side portion 14D, A turning force along each inner surface of the first side portion 14 </ b> A is applied, and the inside of the swirling flow molding chamber 16 is swung along the peripheral wall 14 and the bottom surface 15.

  Further, the air-fuel mixture swirled in the swirling flow molding chamber 16 flows toward the mixing chamber 12 and joins the main flow A flowing in the mixing chamber 12 to form a strong swirling flow C together with the main flow A. This strong swirling flow C suppresses the flow in the direction of the branching portion 4 and increases the mixing distance of the air-fuel mixture in the mixing chamber 12 by the swirling flow, thereby promoting uniform mixing of the intake air and the EGR gas. The air-fuel mixture in which the intake air and the EGR gas are uniformly mixed is distributed to the intake branch pipes 5 in the branch portion 4 and supplied to the cylinders.

  Therefore, according to the present embodiment, the peripheral wall 14 and the bottom wall 15 are located on the opposite side of the branch part 4 from the opening a of the intake pipe 2 of the mixed pipe 10 into which the mixture of intake air and EGR gas is introduced from the intake pipe 2. With a simple configuration in which the bottomed cylindrical expansion portion 13 having the above is formed, a uniform mixing ratio of intake air and EGR gas, that is, variation in EGR rate is reduced.

  Further, since the flow from the inside of the mixing pipe 10 toward the branching section 4 is suppressed, the length of the mixing pipe 10 serving as the mixing section of the air-fuel mixture in the direction of the pipe axis 10L can be shortened, and the pipe line The extended portion 13 protruding in the direction of the shaft 10L is local and compact protruding along the fourth side wall 11D side, and the mountability of the intake manifold 1 is improved.

It should be noted that the shape and size of the expansion portion 13 can be easily set in advance by experiments, simulations, or the like. As a result of the experiment, the volume V in the expansion part 13, that is, the volume V of the swirl flow forming chamber 16 is V> 0. 5 × (D / 2) ² × π × 0.15
That is, a good uniform mixing ratio of intake air and EGR gas was confirmed at a volume more than half of a circular diameter D and a height of 0.15 D with an equivalent area to the cross-sectional area of the mixing pipe 10. .

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. For example, in each of the above embodiments, the air-fuel mixture is introduced along the tangential direction of the cylindrical wall 11 of the mixing pipe 10 by offsetting the pipe axis 2L of the intake pipe 2 with respect to the pipe axis 10L of the cylindrical mixing pipe 10. However, when the air-fuel mixture flowing in the intake pipe 2 flows in a so-called drift state where the air-fuel mixture is biased to one side, the pipe axis 10L of the mixed pipe 10 and the pipe axis 2L of the intake pipe 2 are offset. Since a swirl flow is formed in the mixing pipe 10 without any change, when the air-fuel mixture flowing in the intake pipe 2 flows in a so-called uneven flow state biased to one side, the pipe shaft 10L of the mixing pipe 10 and the intake pipe 2 It is also possible to configure the pipe shaft 2L without offsetting it.

  Moreover, although the case where the mixing pipe 10 has a cylindrical shape or a rectangular cross-sectional shape has been described as an example in the above-described embodiment, it can be formed in other cross-sectional shapes.

It is a perspective view of the intake manifold used as the engine intake device in the first embodiment. It is a principal part perspective view of an intake manifold. It is a figure which shows a mixing part typically. It is the II sectional view taken on the line of FIG. It is the II-II sectional view taken on the line of FIG. It is a figure which shows typically the mixing part in 2nd Embodiment. It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG. It is a figure which shows typically the mixing part in 3rd Embodiment. It is the VV sectional view taken on the line of FIG. It is the VI-VI sectional view taken on the line of FIG. It is a figure which shows typically the mixing part in 4th Embodiment. It is the VII-VII sectional view taken on the line of FIG. It is the VIII-VIII sectional view taken on the line of FIG. It is a figure which shows typically the mixing part in 5th Embodiment. It is the IX-IX sectional view taken on the line of FIG. It is XX sectional drawing of FIG. It is a figure which shows typically the mixing part in 6th Embodiment. It is the XI-XI sectional view taken on the line of FIG. It is the XII-XII sectional view taken on the line of FIG.

Explanation of symbols

1 Intake manifold (intake device)
2 intake pipe 2a opening 2L pipe shaft 3 EGR pipe 4 branching section 5 intake branch pipe 10 mixing pipe 10L pipe shaft 11 cylinder wall 11A first side wall 11B second side wall 11C third side wall 11D fourth side wall 12 mixing chamber 13 Expansion part 14 Peripheral wall 14a Edge 14A 1st side part 14B 2nd side part 14C 3rd side part 14D 4th side part 15 Bottom part 16 Swirling flow formation chamber

Claims (7)

Provided in an engine that recirculates exhaust gas from the exhaust system as EGR gas to the intake system, and has a bottomed cylindrical mixing pipe having a cylindrical wall to which the intake pipe and the intake pipe are connected, and downstream of the mixing pipe A branch portion that branches into a plurality of intake branch pipes communicating with each cylinder, and a mixture of intake air and EGR gas is introduced into the mixture pipe from the opening of the intake pipe in a tangential direction along the inner surface of the cylinder wall Then, after the intake air of the mixture and the EGR gas are mixed by the swirling flow of the mixture formed in the mixture pipe, the mixture is distributed from the branch portion to each intake branch pipe, and each cylinder In the intake system of the engine supplied to
The mixing pipe has the mixing pipe on the side opposite to the branch portion with respect to the opening of the intake pipe and on the side facing the portion of the cylindrical wall where the air-fuel mixture is introduced from the intake pipe along the tangential direction. An intake device for an engine, wherein a bottomed expansion portion that bulges in a pipe axial direction of a pipe is formed. The cylindrical wall of the mixing pipe is cylindrical,
The above extension is
The opening on the opposite side to the distance in the direction of the pipe axis from the opening on the side of the cylindrical wall where the air-fuel mixture is introduced along the tangential direction and is cylindrical. 2. A peripheral wall having an edge that is inclined with respect to the pipe axis so that a distance in the pipe axis direction from the pipe increases, and a bottom wall that closes the edge of the peripheral wall. The engine intake system described in 1. The cylindrical wall of the mixing pipe is cylindrical,
The above extension is
A cylindrical side continuous with the cylindrical wall and a portion of the cylindrical wall into which the air-fuel mixture is introduced along the tangential direction is located in the opening in the pipe axis direction, and the pipe axis extends from the opening on the opposite side. 2. The engine according to claim 1, wherein the engine is formed by a peripheral wall having an edge that is inclined with respect to a pipe axis so as to be separated by a predetermined distance in a direction, and a bottom wall that closes the edge of the peripheral wall. Intake device. The cylindrical wall of the mixing pipe is cylindrical,
The above extension is
A cylindrical wall continuous with the cylindrical wall and a peripheral wall having a substantially semicircular cross section formed continuously with the cylindrical wall on the side facing the cylindrical wall portion into which the air-fuel mixture is introduced along the tangential direction; 2. The engine intake device according to claim 1, wherein the engine intake device is formed by a bottom wall that closes between an edge of the peripheral wall and both side edges of the peripheral wall and a cylindrical wall. The cylinder wall of the mixing pipe has a substantially rectangular cross-sectional shape having a first side wall, a second side wall, a third side wall, and a fourth side wall and is continuous in the pipe axis direction, and the intake pipe line is a second side wall. Opening the first side wall so that the air-fuel mixture is introduced along the tangential direction of the inner surface of
The extension has a first side, a second side, a third side, and a fourth side that are continuous with the first side wall, the second side wall, the third side wall, and the fourth side wall, respectively. It has a rectangular cross section extending in the axial direction and has an edge that is inclined with respect to the pipe axis so as to gradually move away from the opening in the pipe axis direction as it moves from the second side to the fourth side. The engine intake device according to claim 1, wherein the intake device is formed by a peripheral wall and a bottom wall that closes an edge of the peripheral wall. The cylinder wall of the mixing pipe has a substantially rectangular cross-sectional shape having a first side wall, a second side wall, a third side wall, and a fourth side wall and is continuous in the pipe axis direction, and the intake pipe line is a second side wall. Opening the first side wall so that the air-fuel mixture is introduced along the tangential direction of the inner surface of
The extended portion has a first side portion, a third side portion, and a fourth side portion continuous to the first side wall, the third side wall, and the fourth side wall, respectively, and has a U-shaped cross section extending in the pipe axis direction. The peripheral wall having an edge inclined with respect to the pipe axis so as to gradually move away from the opening in the pipe axis direction as it moves from the edge of the second side wall to the fourth side, and the first side wall and the above 2. The engine intake device according to claim 1, wherein the engine intake device is formed by a bottom wall that closes an edge of the peripheral wall. The cylinder wall of the mixing pipe has a substantially rectangular cross-sectional shape having a first side wall, a second side wall, a third side wall, and a fourth side wall and is continuous in the pipe axis direction, and the intake pipe line is a second side wall. Opening the first side wall so that the air-fuel mixture is introduced along the tangential direction of the inner surface of
The extension portion includes a first side portion and a third side portion that are respectively continuous with a range set on the fourth side wall side of the first side wall, a third side wall, and a range set on the fourth side wall side of the third side wall. The fourth side portion is formed by a peripheral wall having a substantially U-shaped cross section formed continuously, and a bottom wall that closes between an edge of the peripheral wall, both side edges of the peripheral wall, and between the cylindrical walls. The engine intake device according to claim 1.

Images