JP2003097369A - Intake system of multi-cylinder internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the versatility of the arrangement of an outlet of an EGR gas in an intake and collection chamber without increasing the parts number, and to increase the rigidity of an intake manifold having a split structure. SOLUTION: An intake system of a multi-cylinder internal combustion engine has an intake manifold M in which an inner member comprising a lower inner member 50 and an upper inner member which are split in upper and lower members is disposed on the inner side of an outer member comprising a lower outer member 30 and an upper outer member which are split in upper and lower members. The intake and collection chamber 20 and an intake passage 21 respectively comprise the lower outer member 30 and the lower inner member 50, and an EGR gas passage forming part 73 with an EGR gas passage 74 formed therein is integrated with the lower inner member 50. The EGR gas flowing from an exhaust introduction pipe 70 flows out into the intake and collection chamber 20 from an outlet 74b of the EGR gas passage 74.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system having a multi-cylinder internal combustion engine and having an intake manifold composed of divided components. More specifically, the intake system is provided with a passage for introducing EGR gas. Regarding the manifold.

[0002]

2. Description of the Related Art Conventionally, in an internal combustion engine, exhaust gas recirculation (EGR) is performed to recirculate exhaust gas taken out from an exhaust system to an intake system in order to purify exhaust gas and improve fuel economy. Various techniques for introducing exhaust gas (EGR gas) into the intake system have been proposed. For example, Japanese Unexamined Patent Publication No. 7-102979 discloses an intake manifold in a V-type 6-cylinder internal combustion engine which is composed of divided constituent members and which is provided with an EGR passage. This intake manifold is configured by stacking a lower block, an intermediate block and an upper block in this order, two surge tanks are formed by the intermediate block and the upper block, and three branch pipes connected to each surge tank are lower. It is formed by a block and an intermediate block. Then, the lower block and the intermediate block are divided along the center line of the branch pipe, whereby each block can be formed by die casting.
Further, the EGR passage is formed on each joint surface of the intermediate block and the upper block, communicates with each surge tank at a gas outlet formed in the intermediate block, and the EGR gas is evenly distributed to each surge tank. .

The intake manifold for a four-cylinder engine disclosed in Japanese Unexamined Patent Publication No. 10-131813 has a surge tank and four branches integrally formed therein, and the surge tank has a throttle body. A spacer for attaching the EGR valve to the surge tank is attached to the end opposite to the attached end, and the gas distribution pipe is fixed to the spacer. The gas distribution pipe is inserted from the sand removal hole of the surge tank, is located in the vicinity of the branch of each branch portion in the surge tank, and is arranged corresponding to each cylinder so that the EGR gas is evenly distributed to each cylinder. Two gas outlets are formed.

[0004]

By the way, in the former prior art, since the EGR passage is formed in the joint surface of both blocks, the intake air is cleaned in order to clean the EGR passage to which the deposit such as carbon adheres. It requires dismantling of the manifold and is not easy to clean. Furthermore, the gas outlet is E
Since the opening is formed in the vicinity of the outer wall where the GR passage is formed, the formation position of the gas outlet in the surge tank is extremely limited, and the gas from the viewpoint of equalizing the EGR gas amount to each cylinder is provided. The degree of freedom in arranging the outlets was small.

On the other hand, in the latter prior art, since the gas distribution pipe is located in the vicinity of each branch of the branch in the surge tank and the gas outlet is provided corresponding to each cylinder, the EGR gas to each cylinder is provided. Although it is considered to be preferable from the viewpoint of making the amount uniform, there is a drawback that the number of parts increases, and further, the gas distribution pipe may hinder the smooth flow of intake air to each branch pipe.

The present invention has been made in view of such circumstances, and the inventions according to claims 1 to 3 are as follows.
In an intake system for a multi-cylinder internal combustion engine, an object is to increase the degree of freedom of arrangement of an EGR gas outlet in an intake collecting chamber without increasing the number of parts, and to increase the rigidity of an intake manifold having a split structure. And And
The invention according to claim 2 further aims to suppress the obstruction of the flow of intake air due to the EGR gas passage being formed in the intake collecting chamber, and the invention according to claim 3 is further characterized in that the EGR gas passage is The purpose is to improve the maintainability of the intake manifold formed.

[0007]

According to a first aspect of the present invention, an intake manifold having an intake collecting chamber and a plurality of intake passages connected to the intake collecting chamber at an upstream end is divided. In the intake system for a multi-cylinder internal combustion engine, the constituent members include an outer member and an inner member arranged inside the outer member, and the intake collecting chamber and the intake passages are provided. Are each formed by the outer member and the inner member, and the inner member is integrally formed with an EGR gas passage forming portion in which an EGR gas passage having an outlet portion for letting out EGR gas into the intake collecting chamber is formed. It is an intake device of a molded multi-cylinder internal combustion engine.

According to the invention described in claim 1, the following effects are exhibited. That is, the passage forming portion for letting out the EGR gas into the intake collecting chamber is a constituent member of the intake manifold and is integrally formed with the inner member forming the intake collecting chamber and the intake passage, thereby increasing the number of parts. Since the EGR gas passage can be formed in the intake collecting chamber without increasing the rigidity, and the rigidity of the inner member itself can be increased, the rigidity of the intake manifold having the divided structure composed of the outer member and the inner member can be increased. You can Further, the inner member is arranged inside the outer member and forms the intake collecting chamber and the intake passage in cooperation with the outer member, so that the EGR gas passage formed in the passage forming portion formed in the inner member is formed. Since the outlet portion can be provided in the intake collecting chamber at a position separated from the outer member forming the outer chamber wall of the intake collecting chamber, the degree of freedom in arranging the outlet portion can be increased, and The outlet can be arranged at an appropriate position from the viewpoint of making the amount of EGR gas supplied to the cylinder uniform.

According to a second aspect of the invention, in the intake system for a multi-cylinder internal combustion engine according to the first aspect, the inner member is
A funnel portion forming the upstream end portion,
The R gas passage forming portion is located behind the upstream end portion, and the peripheral wall of the EGR gas passage forming portion constitutes the funnel portion.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, the following effect is exhibited. That is, the upstream end of the intake passage is formed by the funnel portion, the EGR gas passage forming portion is behind the upstream end portion, and the peripheral wall thereof forms the funnel portion that forms the upstream end portion. It is possible to suppress the formation portion from obstructing the flow of the intake air flowing into the intake passage as much as possible, suppress the decrease in the intake air amount due to the increase in intake resistance, and improve the engine output.

According to a third aspect of the present invention, in the intake system for a multi-cylinder internal combustion engine according to the first or second aspect, the intake manifold is detachably connected to an engine body, and the intake manifold is provided outside the outer member. An exhaust gas introducing pipe connected to the EGR gas passage forming portion is detachably coupled, and the exhaust gas introducing pipe is detachably coupled to the engine body at the coupling portion and controls the flow rate of the EGR gas. By communicating with the control valve, the outlet pipe of the exhaust gas introduction pipe is inserted from the opening formed in the outer member and fitted into the EGR gas passage forming portion, so that the outlet pipe and the EG
The R gas passage forming portion is connected.

According to the invention of claim 3, in addition to the effects of the invention of the cited claim, the following effect is exhibited. That is, the intake manifold is detachably coupled to the engine body, and the introduction pipe member detachably coupled to the outer side of the outer member is detachably coupled to the engine body and communicates with the EGR control valve at the coupling portion. By doing so, the intake manifold can be easily removed from the engine body by removing the intake manifold and the introduction pipe member from the engine body, and by further removing the introduction pipe member from the outer member, the intake manifold is fitted into the passage forming portion. In addition to easily removing the introducing pipe member from the passage forming part,
The inspection for checking the degree of contamination due to the deposits such as carbon adhering to the R gas passage and the cleaning for removing the deposits can be performed through the opening without disassembling the intake manifold. By forming the EGR gas passage forming portion, the maintainability of the intake manifold having the EGR gas passage formed in the intake collecting chamber is improved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. Referring to FIG. 1, a multi-cylinder internal combustion engine E to which an intake device of the present invention is applied is installed vertically in a vehicle body front portion such that a rotation axis of a crank shaft (not shown) is oriented in the front-rear direction of the vehicle. It is a type 8 cylinder internal combustion engine. The internal combustion engine E has eight cylinders 2 in the axial direction A.
(A direction of the rotation axis of the crankshaft, see FIG. 2), a pair of left and right cylinder rows CL and CR formed by arranging four cylinders in a left and right direction are formed into a V-shape, and a left and right cylinder block 1. Pair of left and right cylinder heads 3 respectively connected to the cylinder rows CL and CR, and left and right which are respectively connected to both cylinder heads 3 and form a valve operating chamber for accommodating a valve operating device between the cylinder heads 3. And a pair of head covers 4. A pair of left and right banks BL and BR forming a V shape are formed by the left and right cylinder rows CL and CR, the cylinder head 3 and the head cover 4, and the cylinder block 1 and the cylinder head 3 constitute an engine body.

In this embodiment, the "axial direction" means the direction of the axis of rotation of the crankshaft of the internal combustion engine E unless otherwise specified, and "up and down" and "left and right" are not specified. As far as the internal combustion engine E is viewed from the axial direction A,
The “upper and lower sides” and the “left and right sides” in FIG. 1, which are views when the dividing surface of the outer member M1 is a horizontal plane, are meant. Therefore, when the internal combustion engine E is mounted on the vehicle, "upper and lower" and "left and right" with respect to the vehicle correspond to "up and down" and "left and right" in the embodiment, respectively. Also, since the structures of the left and right banks BL and BR are basically the same, the following mainly describes the left bank BL.
The same reference numerals are given to corresponding portions in the right bank BR.

A piston 5 reciprocally fitted in a cylinder hole 2a of each cylinder 2 rotationally drives the crankshaft rotatably supported by the cylinder block 1 via a connecting rod. In the cylinder head 3, for each cylinder 2, a combustion chamber 6 formed of a recess formed at a position facing the cylinder hole 2a, and a pair of intake valve openings 7a opening in the combustion chamber 6 are formed.
And an exhaust port 8 having a pair of exhaust valve openings 8a that open into the combustion chamber 6, and are driven by the valve operating device in synchronization with the crankshaft to provide both intake valves. A pair of intake valves 9 and a pair of exhaust valves 10 for opening and closing the port 7a and both exhaust valve ports 8a at predetermined timings are provided.

Further, each intake port 7 is connected to the left and right banks.
There is one opening 7b on the side surface of the cylinder head 3 on the space S side formed between BL and BR. The intake manifold M arranged in the space S and connected to the cylinder head 3 has a size that suppresses the pressure fluctuation of the intake air caused by the opening and closing of the intake valve 9 while the intake air whose flow rate is controlled by the throttle valve 11 flows in. And an eight intake passages 21 connected to the intake collection chamber 20 at the upstream end 21a and connected to the opening 7b of the intake port 7 at the downstream end 21b.
Have and. These intake passages 21 arranged side by side in the axial direction A
Is composed of four left bank side intake passages 21L connected to the intake port 7 of the left bank BL and four right bank side intake passages 21R connected to the intake port 7 of the right bank BR. The passages 21L and the right bank side intake passages 21R are alternately arranged one by one in the axial direction A, and further eight intake passages 21 are divided into two in the axial direction A with a communication passage 46, which will be described later, interposed therebetween (see FIG. 2). On the other hand, in each bank BL, BR, each exhaust port 8 has one opening on the side surface of the cylinder head 3 on the side opposite to the space S side, and eight exhaust manifolds (not shown) are provided at these openings. The exhaust passages are connected to each other.

Each intake passage 21 is switched between a long intake passage 22 and a short intake passage 23 which are switched by opening and closing an intake control valve 24 provided in the intake passage 21 according to the engine speed.
Composed of and. The long intake passage 22 serves as an intake supply passage to the intake port 7 when the internal combustion engine E is operated in the low speed rotation range where the engine speed is equal to or lower than a predetermined value, and the inertia supercharging effect in the low speed rotation range is provided. It is set to the length of the intake passage that is effective. The short intake passage 23 serves as an intake supply passage to the intake port 7 when the internal combustion engine E is operated in a high speed rotation range in which the engine speed exceeds the predetermined value, and the inertia supercharging effect in the high speed rotation range is provided. The intake passage length is set to be effective, and the intake passage length is shorter than that of the long intake passage 22. The intake collecting chamber 20 includes an upstream end 22 of each long intake passage 22.
a and an upstream end portion 23a of a short intake passage 23 provided with an intake control valve 24 that is fully closed in the low speed rotation range and fully opened in the high speed rotation range are connected together.

Referring to FIGS. 2 and 3 together, the intake manifold M is formed by injection molding using a synthetic resin as a molding material, or by die casting using a light metal such as aluminum or magnesium or an alloy thereof as a molding material. A main body is provided, and the main body has a multi-divided structure composed of divided constituent members. Specifically, the main body is divided into an upper and lower outer member M1, and an inner member M2 that is disposed inside the outer member M1 and is vertically divided.
Composed of and. Therefore, the intake manifold M is composed of the main body forming the intake collecting chamber 20 and the intake passage 21, and various members described later that are connected to the main body.

The outer member M1 is vertically divided into a lower outer member 30 and an upper outer member 40 by a horizontal dividing surface D1 (see FIG. 1). The lower outer member 30 and the upper outer member 40 are detachably coupled with a plurality of bolts (not shown), and the lower outer member 30 is coupled with the cylinder head 3 with a plurality of bolts (not shown).
The intake manifold M is detachably connected to the cylinder head 3. On the other hand, the inner member M2 is vertically divided into a pair of lower inner member 50 and a pair of upper inner member 60 by the dividing surface D2 (see FIG. 1) that is on the same plane as the dividing surface D1. .

The lower outer member 30 has both end walls 31 and 32 in the axial direction A and a peripheral wall 33 which is curved so as to be convex downward, and some of these walls 31 to 33 are used as passage walls. Intake passage 21
Of the first passage P1 which is a part of the above, and the intake collecting chamber 20 is formed by using a part of these walls 31 to 33 as a lower outer chamber wall. Specifically, on the left and right side portions of the peripheral wall 33, five mounting seats 35, which are formed to bulge inward and to which the lower inner member 50 is fitted, are arranged at intervals in the axial direction A. Further, it is formed in a range from the bottom of the lower outer member 30 to the division surface D1.
A portion of each mounting seat 35 near the bottom portion is a curved portion 35b curved in a flare shape so as to form the upstream end portion 22a of the long intake passage 22. Then, in the left and right side portions of the lower outer member 30, between the mounting seats 35 adjacent in the axial direction A, and between the mounting seat 35 and the end wall 31 or the end wall 32, one of the peripheral walls 33 is formed. Due to the groove 36 formed with the portion as the outer wall 34, the axial direction A
An outer portion of the first passage P1 that is curved in a J shape when viewed from above is formed.

On the left and right side portions of the lower outer member 30,
A third passage P3 that is connected to the intake port 7 and is a part of the intake passage 21 is formed.
A fuel injection valve 14 for injecting fuel toward the pair of intake valve ports 7a is attached. Further, in the end wall 32, a tubular mounting portion 37 forming an opening portion 37a formed of a long hole that is long in the left-right direction,
Is formed outside the lower outer member 30 so as to extend in the axial direction A,
An exhaust introduction pipe 70 having a pair of outlet pipes 70b inserted into the openings 37a is detachably connected to the mounting portion 37 by three bolts F1 (see FIG. 5). The exhaust gas introducing pipe 70 converts the exhaust gas taken out from the exhaust system including the exhaust port 8 and the exhaust manifold into EGR gas (recirculation exhaust gas).
In order to recirculate the exhaust gas to the intake system and perform exhaust gas recirculation (EGR), the EGR gas after the flow rate is controlled by the EGR control valve 75 (see FIG. 5) is introduced into the intake collecting chamber 20. Details of the exhaust introduction pipe 70 will be described later.

Referring also to FIG. 4, the lower outer member
Both lower inner members designed to the same specifications to be stored in 30
50 are arranged inside the lower outer member 30 in the left-right direction which is a direction orthogonal to the axial direction A, and moreover, the lower outer member 30.
(Thus, the center point CP (center plane CP1) of the lower outer member 30 when seen from the division plane D1 in plan view with the center plane CP1 located in the center in the left-right direction of the intake manifold M interposed therebetween.
And a central plane orthogonal to the axial direction A and located at the center of the lower outer member 30 and the upper outer member 40 in the axial direction A.
It is arranged in point symmetry with respect to the line of intersection with CP2 and the plane containing the dividing surface D1, and is joined to the lower outer member 30.

Each lower inner member 50, which is a partition member for partitioning the intake air collecting chamber 20 and the intake passage 21, is formed by integrally forming a plate-like intake passage forming portion 51 and a circular pipe-like passage forming portion 52. (See Figure 3). The intake passage forming portion 51 forms an inner wall 53 that serves as a passage wall of the first passage P1 and a flat partition wall 54, and a pair of partition walls that are adjacent in the axial direction A with the inner wall 53 sandwiched therebetween.
The four grooves 55 formed between 54 form the inner portion of the first passage P1.

The lower outer member 30 and each lower inner member 50 are fitted to each other at the fitting portion H1 to form the intake air collecting chamber 20 and the first passage P1. The fitting part H1 is
It is composed of a first step portion formed on the lower outer member 30 and a tip end portion 54a of each partition wall 54 fitted to the first step portion.
The first step portion includes a step portion 35a (see FIG. 3) formed at the peripheral edge of the mounting seat 35 facing the groove 36, and step portions 31a, 32a formed inside the end walls 31, 32. (See FIGS. 2 and 3). Thereby, the lower outer member in each first passage P1
30 and the lower inner member 50 along the first passage P1,
The dividing surface V1 (see FIG. 1) along the center line N of the intake passage 21 (long intake passage 22) when viewed from the axial direction A is formed by the mating surface of the fitting portion H1. Therefore, at the dividing surface V1, the end walls 31, 32 and the mounting seat 35 are in surface contact with the partition wall 34, so that leakage of intake air is suppressed and airtightness is secured.

Referring to FIGS. 2 and 4, the pair of circular tubular passage forming portions 52 has an axis extending in the axial direction A, and is located near the center of the lower outer member 30 in the left-right direction. It is divided into two in the axial direction A with the center plane CP2 interposed. Then, in each passage forming portion 52, a passage 56 having both ends opened is formed. The passage 56, which has a circular passage cross-section, includes an end wall 31,
32 has an end opening 56a located inwardly of the intake collecting chamber 20 from the lower outer member 30 and a central opening 56b located in the central portion 20a of the intake collecting chamber 20. It is composed of a hole that tapers from the partial opening 56a toward the central opening 56b. Therefore, the central opening 56b is also located at a position separated from the lower outer member 30 inward of the intake collection chamber 20. Further, each passage forming portion 52 is located behind the upstream end portions 22a of the two first passages P1 opening to the intake collecting chamber 20 (see FIG. 1), and the upstream end portions 22a and the first passages in the vicinity thereof are located. P
A wall connecting to the inner wall 53 of the portion 1 is also formed, and the passage forming portion 5
The peripheral wall 52c formed by the two cylindrical walls constitutes the upper funnel portion 57a forming the upstream end 22a, and the flare-shaped curved portions 54b of the pair of partition walls 54 and the curved portion 35b of the mounting seat 35 which face each other in the axial direction A. Constitute the side funnel portion 57b (see FIG. 2).

Referring to FIGS. 1-3, the upper outer member
Reference numeral 40 denotes a communication passage 46 for guiding the intake air introduced from the outer end walls 41, 42 in the axial direction A and the intake inflow portion 45 described later to the central portion 20a in the axial direction A and the left-right direction of the intake collection chamber 20. It has a pair of inner end walls 43 opposed to each other across and a peripheral wall 44 curved so as to be convex upward, and a part of these walls 41 to 44 is used as a passage wall in a part of the intake passage 21. A second passage P2 and surrounding wall
An intake air inflow portion 45 is formed by a part of 44. Specifically, as shown in FIG. 2, an intake inflow portion 45 that passes through the center plane CP2 and forms an inflow passage 45a along the center plane CP2 is provided at the central portion of the peripheral wall 44 in the axial direction A. It is formed. Then, as shown in FIGS. 1 and 2, which is provided on the right side of the intake inflow portion 45 in the left-right direction, the connecting portion 45b forming the inlet portion 45a1 of the inflow passage 45a is made of an aluminum alloy. The throttle base 12 is coupled, and the throttle base 12 is further coupled with the throttle body 13 having the throttle valve 11 mounted thereon. As a result, an intake device including the throttle base 12 and the throttle body 13 as intake intake members and the intake manifold M is configured.

Further referring to FIGS. 2 and 3, the peripheral wall 44
A partition wall 47 having a side wall 47a facing in the axial direction A is formed in the partition wall 47 between the partition walls 47 adjacent in the axial direction A, and between the partition wall 47 and the outer end walls 41, 42 or the inner end wall 43. Between
By the groove 49 formed by forming a part of the peripheral wall 44 as the outer wall 48,
An outer portion of the second passage P2 that is curved so as to be convex upward when viewed from the axial direction A is formed.

A bracket 90 to which a negative pressure actuator 91 for driving the intake control valve 24 is attached is connected to the outer end wall 41 of the upper outer member 40. The actuator 91 has a rod 92 connected to the diaphragm,
Two actuating shafts 94, which are rotatably supported by a body 97 of a valve unit 95 described later, are turned through a link / lever mechanism 93 arranged in the intake air collecting chamber 20, so that each actuating shaft 94 can be rotated. All of the intake control valves 24, which are fixed four by four, are simultaneously opened and closed according to the engine rotation speed.

Both upper inner members 60, which are designed to have the same specifications and are housed in the upper outer member 40, are arranged inside the upper outer member 40 in the axial direction A (see FIG. 2), and although not shown, a center plane is formed. The center point of the upper outer member 40 when viewed from the dividing surface D1 in plan view across CP2 (the point that coincides with the center point CT, the intersection line between the central plane CP1 and the central plane CP2, and the dividing plane).
It is arranged in point symmetry with respect to the intersection with the plane containing D1),
It is joined to the upper outer member 40.

Each upper inner member 60 has a plate-shaped intake passage forming portion 61 and a storage portion 62 for the valve unit 95. The intake passage forming portion 61 forms an inner wall 63 that serves as a passage wall of the second passage P2 and a flat partition wall 64, and a pair of partition walls 64 that are adjacent to each other in the axial direction A with the inner wall 63 sandwiched therebetween. The inner portion of the second passage P2 is formed by the four grooves 65 formed between the two. Further, a connection portion 66 (see also FIG. 1) having a circular opening and to which an air funnel 96 described later is connected is formed in a part of the inner wall 63. The upper inner member 60 also forms an outer chamber wall above the intake air collection chamber 20.

Then, the upper outer member 40 and each upper inner member 60 are fitted to each other at the fitting portion H2, so that the second
A passage P2 is formed. The fitting portion H2 between the upper outer member 40 and each upper inner member 60 includes a second step portion and a groove portion T formed in the upper outer member 40, and a partition wall 64 that fits in the second step portion and the groove portion T. And a tip portion 64a of the. The second step is the outer end wall 4 of the upper outer member 40.
1, 42 and steps 41a, 42a, 43a of the inner end wall 43 and the partition wall
It is composed of 47 steps 47a1 (see FIG. 1). here,
The stepped portions 41a, 42a, 43a are stepped bulged portions 41b, 4 formed by bulging the end walls 41, 42, 43 outward in the axial direction A.
Steps 47a1 of the partition wall 47 formed by 2b and 43b, respectively.
Is formed by a stepped bulge 47b formed by bulging the side wall 47a outward in the axial direction A. As a result, the dividing surface V2 of the upper outer member 40 and the upper inner member 60 in each second passage P2 along the second passage P2 is
It is composed of H2 mating surfaces. Therefore, on the dividing surface V2, the outer end walls 41, 42, the inner end wall 43, and the partition wall 47.
Since the partition wall 64 and the partition wall 64 make surface contact with each other, leakage of intake air is suppressed and airtightness is secured.

Further, the valve unit 95 is housed in the housing portion 62 formed inside the lower portion of the upper inner member 60.
The valve unit 95 forms an upstream end portion 23a of the short intake passage 23 to the intake collecting chamber 20 and is integrally formed with eight air funnels 96 that connect the intake collecting chamber 20 and the second passage P2. And the intake control valve 24 mounted in each of the air funnels 96 are integrated. Each air funnel
As shown in FIG. 4, in which only the inner peripheral wall surface 96a of the end portion of the air funnel 96 near the connecting portion 66 is indicated by a chain double-dashed line, the short lengths 96 on the left bank side are alternately arranged in the axial direction A. In correspondence with the intake passage 23 and the short intake passage 23 on the right bank side,
In the axial direction A, the connecting portions 66 of the upper inner member 60 are alternately arranged on the left side and the right side with the center plane CP1 interposed therebetween.
Connected to. Therefore, the valve unit 95 is a member that constitutes the intake manifold M together with the main body.

In this way, the long intake passages 22 are
The short intake passage 23 is formed from the third passages P1 to P3, the air funnel 96, a part of the second passage P2 and the third passage P3, and the intake collecting chamber 20 is mainly composed of the lower outer members 30 and 1 It is formed of a pair of lower inner members 50. Therefore, the short intake passage 23 joins the long intake passage 22 on the downstream side of the air funnel 96. And the long intake passage 22
The short intake passage 23 covers the upper part of the intake collecting chamber 20. Furthermore, the upstream end 22a of the long intake passage 22 is a lower part of the intake collecting chamber 20 and opens to the left or right, and the upstream end 23a of the short intake passage 23 is an upper part of the intake collecting chamber 20. ,
Open downward. Then, those upstream end portions 22a, 2
As shown in FIG. 4, 3a is bisected in the axial direction A by the central portion 20a of the intake collection chamber 20 including the central plane CP2.

By the way, referring to FIGS. 2, 4 and 5, the exhaust introduction pipe 70 coupled to the mounting portion 37 of the lower outer member 30 is provided with a flange 71 as a coupling portion to the engine body.
And an inlet pipe 70a provided with the flange 71, and a pair of straight tubular outlet pipes 70b are integrally molded, and inside thereof, as shown in FIGS. E formed by the passage forming portion 52 of the lower inner member 50
A gas passage 72 for supplying EGR gas is formed in the EGR gas passage 74 of the GR gas passage forming portion 73. Gas passage 72
Of the gas passage 72 is formed in each of the outlet pipes 70b and is connected to the inlet portion 74a formed in the EGR gas passage forming portion 73.

The two outlet pipes 70b inserted into the intake collecting chamber 20 through the openings 37a as described above have ends of the pair of left and right passage forming portions 52 close to the end wall 32 close to the end wall 32. The exhaust gas introducing pipe 70 is fitted and connected to the inside of the portion 52a, and then the exhaust gas introducing pipe 70 is fixed to the mounting portion 37 by the bolt F1. As a result, in the intake collecting chamber 20, the pair of end openings 56a and the corresponding pair of outlets 72b are connected, and the EGR gas flowing in from the exhaust introduction pipe 70 flows through the passage 56 and the central opening. It flows out from the portion 56b to the central portion 20a of the intake collection chamber 20. Therefore, the passage forming portion 52 connected to the exhaust gas introduction pipe 70 forms the EGR gas passage forming portion 73, and the passage 56, the end opening 56a, and the central opening 56b form the EGR gas in the intake collecting chamber 20. Gas passage 7
4, the inlet portion 74a and the outlet portion 74b are respectively formed. Then, the EGR gas flows into the intake collecting chamber 20 in a direction substantially orthogonal to the main flow of the intake air flowing downward from the communication passage 46 into the intake collecting chamber 20, and when the EGR gas flows through the EGR gas passage 74, the EGR gas The gas passage 74 is from the inlet portion 74a to the outlet portion 74b.
As it tapers toward, the outflow rate is increased.

Further, the entire EGR gas passage 74 is opposed to the opening 37a in the axial direction A, and as shown in FIG. 6, the end wall 32 of the lower outer member 30 is moved in the intake manifold in the axial direction A. When viewed from the outside of M, the EGR gas passage forming portion 73 is formed in the lower inner member 50 so that the entire EGR gas passage 74 faces the opening 37a. Therefore, by removing the exhaust introduction pipe 70 from the lower outer member 30, the opening
Through 37a, it is possible to perform an inspection for checking the degree of contamination due to deposits such as carbon attached to the EGR gas passage 74, and to clean the deposits. Therefore, the opening 37a also serves as an opening for inspection and cleaning of the EGR gas passage 74.

Referring to FIG. 5, the exhaust introduction pipe 70 has a flange 71, a cylinder block 1 and a cylinder head 3 at the boss G by bolts (not shown).
Is detachably coupled to a pipe unit 80 fixed to the. That is, the pipe unit 80 in which the cooling water passage 83 and the gas passage 84 are formed side by side through the partition wall 80a is integrally formed with two flanges 81 and 82 as coupling portions. The flange 71 of the exhaust introduction pipe 70 and the EG
The flange 76 of the R control valve 75 is coupled by the stud bolts F2 and F3, respectively, so that the exhaust introduction pipe 70 and the EG
An R control valve 75 is connected to the engine body via a pipe unit 80.

The cooling water passage 83 of the pipe unit 80 is
The cooling water after cooling the cylinder head 3 constitutes a part of the cooling water supply passage for supplying the cooling water to the heater core of the vehicle air conditioner, and the cooling water jacket provided on the cylinder head 3 through the communication hole 85. Communicate with. Also, the gas passage
Reference numeral 84 denotes an EGR gas taken out from the exhaust system.
The control valve 75 is supplied to an inlet portion 84a thereof, which is connected to a gas passage (not shown) of an EGR gas extraction pipe communicating with the exhaust system, and an outlet portion (not shown) opening to the flange 82. , EGR control valve 75 is connected to the inflow passage. Then, since the gas passage 84 extends along the cooling water passage 83, the EGR gas is cooled by the cooling water flowing through the cooling water passage 83 by heat exchange through the partition wall 80a. Further, in the pipe unit 80, an inlet portion (not shown) opening to the flange 82 and an outlet portion 86b opening to the flange 81.
A communication passage 86 having a
EGR gas whose flow rate is controlled by the control valve 75 is an exhaust introduction pipe
It is led to the gas passage 72 of 70.

The EGR control valve 75 controls the amount of EGR gas according to the engine operating conditions such as the rotation speed and load of the internal combustion engine E by a drive signal from a control device (not shown). And the outflow passage through which the EGR gas whose flow rate is controlled flows
The flange 82 connects to the inlet of the communication passage 86.

Next, the operation and effect of the embodiment configured as described above will be described. When the internal combustion engine E is operated, the intake air whose flow rate is controlled by the throttle valve 11 descends from the inflow passage 45a of the intake inflow portion 45 through the communication passage 46 and flows into the intake collection chamber 20. Then, when the internal combustion engine E is operated in the low speed rotation range, the intake control valve 24 is in a fully closed state, and the intake air that has flowed into the intake collecting chamber 20 is a long intake passage.
22 to reach each intake port 7 and further fuel injection valve 14
It is supplied to the combustion chamber 6 together with the fuel supplied from. At this time, the intake air is supplied to the combustion chamber 6 through the long intake passage 22 having an intake passage length with which an effective supercharging effect can be obtained in this engine operating region, so that high volume efficiency is achieved. Torque is obtained. Further, when the internal combustion engine E is operating in the high speed rotation range, the intake control valve 24 is fully opened,
The intake air that has flowed into the intake air collection chamber 20 reaches each intake port 7 through the short intake passage 23 having a low ventilation resistance, and is further supplied to the combustion chamber 6 together with the fuel supplied from the fuel injection valve 14. At this time as well, the intake air is a short intake passage having an intake passage length that provides an effective inertia supercharging effect in this engine operating range.
Since it is supplied to the combustion chamber 6 through 23, high torque can be obtained with high volume efficiency.

Further, the EGR gas taken out from the exhaust system is cooled by the cooling water in the pipe unit 80 and flows into the EGR control valve 75, and the flow rate is controlled by the EGR control valve 75 according to the engine operating state. , Exhaust passage 70 via communication passage 86
Of the gas passage 72, and a pair of outlets 72b of the gas passage 72
From the one formed on the pair of lower inner members 50, respectively.
It flows into the EGR gas passage 74 of the paired EGR gas passage forming portion 73. The EGR gas is accelerated through the tapered EGR gas passage 74, flows out from the pair of outlets 74b that open to the central portion 20a of the intake collecting chamber 20, and passes through the communication passage 46 to the inside of the intake collecting chamber 20. It mixes with the intake air flowing into the. Then, the intake air in the state where the mixing with the EGR gas is promoted in the intake collecting chamber 20 passes from the upstream end portions 22a and 23a to the long intake passage 22 or the short intake passage 23, and passes through the intake port 7 to the combustion chamber 6 Is supplied to.

Here, an inner member M2 made up of the lower and upper inner members 50, 60 divided vertically is arranged inside the outer member M1 made up of the lower and upper outer members 30, 40 divided up and down. Configured intake manifold M
In the above, the EGR gas passage forming portion 73 for causing the EGR gas to flow into the intake collecting chamber 20 is a constituent member of the intake manifold M, and is the first member of the intake collecting chamber 20 and the intake passage 21.
By being integrally formed with the lower inner member 50 forming the passage P1, the intake collecting chamber 20 can be formed without increasing the number of parts.
Since the EGR gas passage 74 can be formed inside and the rigidity of the lower inner member 50 itself can be increased,
It is possible to increase the rigidity of the intake manifold M having a divided structure composed of the outer member M1 and the inner member M2. Further, the lower inner member 50 is disposed inside the lower outer member 30, and is formed in the lower inner member 50 by forming the intake collecting chamber 20 and the first passage P1 in cooperation with the lower outer member 30. The outlet portion 74b of the EGR gas passage 74 formed in the EGR gas passage forming portion 73 is connected to the intake collecting chamber 20.
Since it can be provided in a position separated from the lower outer member 30 forming the outer chamber wall of the intake air collection chamber 20, it is possible to increase the degree of freedom of arrangement of the outlet portion 74b, for example, for each combustion The outlet part 74b can be arranged at an appropriate position from the viewpoint of equalizing the EGR gas amount supplied to the chamber 6.

Further, the outlet portion 74b of the EGR gas passage 74
Is the upstream end of the intake passage 21 connected to the intake collection chamber 20.
Since the upstream end portions 22a and 23a of the long intake passage 22 and the short intake passage 23, which are 21a, are caused to flow out to the central portion 20a of the intake collecting chamber 20 which divides the upstream end portions 22a and 23a in the intake collecting chamber 20 into the axial direction A, The amount of EGR gas supplied to each combustion chamber 6 through the intake passage 21 can be made substantially equal. Moreover,
The EGR gas flows into the intake collecting chamber 20 in a direction substantially orthogonal to the main flow of the intake air flowing downward from the communication passage 46 into the intake collecting chamber 20, and the EGR gas flows from the inlet portion 74a to the outlet portion 7a.
Since the outflow speed is increased by the EGR gas passage 74 which is tapered toward 4b, the main flow of intake air is
Before reaching the upstream end 21a of the intake air collecting chamber 20
Since the mixing of the EGR gas and the intake air is promoted by this, it is possible to contribute to the uniform supply of the EGR gas amount to each combustion chamber 6 also in this respect.

The EGR gas passage forming portion 73 is a pair of lower inner members located side by side in the left-right direction with the center plane CP2 interposed therebetween.
By forming 50, even if one of the EGR gas passages 74 is blocked by a deposit, the EGR gas can be supplied from the other EGR gas passage 74, so that the effect of exhaust gas purification and fuel efficiency improvement by EGR is maintained. it can. Also, EG
A pair of lower inner members in which the R gas passage forming portion 73 is formed
By designing 50 to the same specifications, lower inner member
Since 50 can be used in common, the cost of the intake manifold M including the EGR gas passage forming portion 73 in the intake collecting chamber 20 can be reduced due to the simplification of the manufacturing apparatus and the effect of mass production, and the replacement of members and the cost. It is also advantageous in maintenance in terms of the above.

The upstream end portion 22a of the long intake passage 22 allows the intake air in the intake collecting chamber 20 to be discharged in a state where the pressure loss is small.
The EGR gas passage forming portion 73 is formed by the funnel portions 57a and 57b for allowing the EGR gas passage forming portion 73 to flow into the flow path 22, and the peripheral wall 52c constitutes the funnel portion 57a. It is possible to suppress as much as possible the 73 blocking the flow of the intake air flowing into the long intake passage 22, suppress the decrease in the intake air amount due to the increase in intake resistance, and improve the engine output.

The intake manifold M is detachably coupled to the cylinder head 3, and the exhaust introduction pipe 70 detachably coupled to the outer side of the lower outer member 30 has a flange 71 at the flange 71 through the pipe unit 80. The intake manifold M can be easily removed from the cylinder head 3 by removing the intake manifold M and the exhaust introduction pipe 70 from the cylinder head 3 by connecting the intake manifold M to the EGR control valve 75. Further, by removing the exhaust introduction pipe 70 from the mounting portion 37 of the lower outer member 30, E
The exhaust gas introduction pipe 70 fitted in the GR gas passage forming portion 73 is
In addition to being easily removable from the GR gas passage forming portion 73, the intake manifold M is used for the inspection for checking the degree of dirt due to the deposits such as carbon adhered to the EGR gas passage 74 and the cleaning for removing the deposits. Can be carried out through the opening portion 37a without disassembling the exhaust gas. Therefore, by forming the EGR gas passage forming portion 73 in the lower inner member 50, the intake manifold in which the EGR gas passage 74 is formed in the intake collecting chamber 20 is formed. The maintainability of M is improved.

Moreover, when the end wall 32 of the lower outer member 30 is viewed from the outside of the intake manifold M in the axial direction A, EGR
Since the EGR gas passage forming portion 73 is formed in the lower inner member 50 so that the entire gas passage 74 faces the opening portion 37a, the inspection and cleaning through the opening portion 37a becomes easier.

In the following, an example in which a part of the configuration of the above-described example is modified will be described with respect to the modified configuration.
Although the exhaust introduction pipe 70 and the EGR control valve 75 are indirectly connected to the cylinder block 1 and the cylinder head 3 via the pipe unit 80 in the above-described embodiment, the pipe unit 80
It may be directly coupled to the cylinder head 3 or the cylinder block 1 without an intermediate member such as.
And, in this specification, "bonding" means indirect bonding and direct bonding.

In the above-described embodiment, the lower inner member forming the intake air collecting chamber 20 is the pair of lower inner members 50, but it may be a single lower inner member. Further, the number of the outlet pipe 70b and the number of the EGR gas passage forming portion 73 may each be one. Further, the first passage P1 of the intake passage 21, which is formed by the lower outer member 30 and the lower inner member 50 together with the intake collecting chamber 20, has a dividing surface along the center line of the intake passage 21, but, for example, The first passage P1 may have a dividing surface that intersects with the center line, as in the case where the first passage P1 is partially formed by the tubular outer member M1 and inner member M2.

Although the EGR gas passage 74 is entirely exposed to the opening 37a in the above embodiment, the EGR gas passage is reduced in ease of inspection and cleaning as compared with the embodiment.
The inlet 74a of the hole 74 may face the opening 37a and face the opening 37a when viewed in the axial direction A. Also,
The internal combustion engine E may be a V-type internal combustion engine other than the 8-cylinder engine, or may be a multi-cylinder internal-combustion engine arrayed other than the V-type engine.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an intake system for a multi-cylinder internal combustion engine that is an embodiment of the present invention, and is a cross-sectional view taken along the line I-I of FIG.

FIG. 2 is a sectional view taken along line II-II of FIG.

3 is a schematic exploded perspective view of an intake manifold of the intake device of FIG.

FIG. 4 is a plan view of the lower outer member of the intake manifold of FIG. 1 assembled with a lower inner member, as viewed from above.

5 is a side view of essential parts showing the positional relationship between the exhaust introduction pipe and the EGR control valve when the intake manifold of FIG. 1 is viewed in the axial direction.

FIG. 6 is a side view of essential parts showing a positional relationship between an opening of a mounting portion of an exhaust introduction pipe and an EGR gas passage forming portion when FIG. 1 and the intake manifold are viewed in the axial direction.

[Explanation of symbols]

1 ... Cylinder block, 2 ... Cylinder, 3 ... Cylinder head, 4 ... Head cover, 5 ... Piston, 6 ... Combustion chamber,
7 ... intake port, 8 ... exhaust port, 9 ... intake valve, 10 ... exhaust valve, 11 ... throttle valve, 12 ... throttle base, 13 ...
Throttle body, 14 ... Fuel injection valve, 20 ... Intake collection chamber,
20a ... Central part, 21 ... Intake passage, 21a ... Upstream end part, 22 ... Long intake passage, 23 ... Short intake passage, 24 ... Intake control valve, 30 ... Lower outer member, 31, 32 ... End wall, 33 ... peripheral wall, 34 ... outer wall, 35 ... mounting seat, 36 ... groove, 37 ... mounting part, 37a ... opening, 4
0 ... Upper outer member, 41-43 ... End wall, 44 ... Perimeter wall, 45 ...
Intake air inlet, 46 ... Communication passage, 47 ... Partition wall, 48 ... Outer wall, 50
... lower inner member, 51 ... intake passage forming portion, 52 ... passage forming portion, 53 ... inner wall, 54 ... partition wall, 55 ... groove, 56 ... passage, 57
a, 57b ... Funnel portion, 60 ... Upper inner member, 61 ... Intake passage forming portion, 62 ... Storage portion, 63 ... Inner wall, 64 ... Partition wall, 65
… Grooves, 66… Connections, 70… Exhaust gas introduction pipes, 70b… Outlet pipes, 71
... flange, 72 ... gas passage, 73 ... EGR gas passage forming portion, 74 ... EGR gas passage, 74b ... outlet portion, 75 ... EGR control valve, 80 ... pipe unit, 81, 82 ... flange, 83 ... cooling water passage, 84 ... Gas passage, 85 ... Communication hole, 86 ... Communication passage, 90 ... Bracket, 91 ... Actuator, 92 ... Rod, 93 ... Link / lever mechanism, 94 ... Actuating shaft, 95 ... Valve unit, 96 ... Air funnel, 97 ... Body, E ... Internal combustion engine, CL, CR ... Cylinder row, BL, BR ... Bank, A ... Axial direction, S ... Space, M
... intake manifold, M1 ... outer member, M2 ... inner member,
D1, D2 ... Dividing surface, P1-P3 ... Passage, F1-F3 ... Bolt, CP
1, CP2 ... Center plane, CT ... Center point, H1, H2 ... Fitting section, T ... Groove section, G ... Boss section.

Claims (3)

[Claims] 1. An intake system for a multi-cylinder internal combustion engine, wherein an intake manifold having an intake collecting chamber and a plurality of intake passages connected to the intake collecting chamber at an upstream end is composed of divided constituent members. The constituent member includes an outer member and an inner member arranged inside the outer member, and the intake collecting chamber and the intake passages are respectively formed by the outer member and the inner member, The inner member includes EG
An intake system for a multi-cylinder internal combustion engine, wherein an EGR gas passage forming portion having an EGR gas passage having an outlet portion for letting out R gas into the intake collecting chamber is integrally formed. 2. The inner member has a funnel portion that forms the upstream end portion, the EGR gas passage forming portion is located behind the upstream end portion, and a peripheral wall of the EGR gas passage forming portion is formed. The intake system for a multi-cylinder internal combustion engine according to claim 1, wherein the funnel portion is configured. 3. The intake manifold is detachably coupled to an engine body, and an exhaust introduction pipe connected to the EGR gas passage forming portion is detachably coupled to an outer side of the outer member. An opening formed in the outer member such that an outlet pipe of the exhaust gas introduction pipe is detachably connected to the engine body and communicates with an EGR control valve that controls the flow rate of EGR gas at the connecting portion. The multi-cylinder according to claim 1 or 2, wherein the outlet pipe and the EGR gas passage forming portion are connected by being inserted from above and fitted into the EGR gas passage forming portion. Intake device for internal combustion engine.