JP2003097242A - Intake manifold of multicylinder internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake manifold having a blowby gas passage formed in a split surface, wherein upsizing of the intake manifold is suppressed, and mounting work of a sealing member is facilitated, while preventing intake on the split surface and leakage of blowby gas. SOLUTION: An intake manifold of a multicylinder internal combustion engine is configured by arranging the lower inner member 50 and the upper inner member 60 in the inside of the split lower outer member 30 and the upper outer member 40. A seal groove having the first groove 71 and the second groove 72 surrounding the intake passage 21 is formed on the split surface D1L of the lower outer member 30, with respect to the upper outer member 40 and the upper inner member 60 jointly forming an intake passage 21. The third groove 74 having an outlet 76a opened to the intake passage 21 is formed on the bottom wall 75a of the second groove 72. The sealing member integrally formed by the first sealing part 81 and the second sealing part 82 mounted in the first groove 71 and the second groove 72, respectively is mounted. The blowby gas passage 76 is formed by covering the third groove 74 with the second sealing part 82.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake manifold formed of divided components of a multi-cylinder internal combustion engine, and more particularly to an intake manifold having a blow-by gas passage for returning blow-by gas to an intake system. Regarding the manifold.

[0002]

2. Description of the Related Art Conventionally, as an intake manifold of this type,
Japanese Unexamined Patent Publication No. 7-102979 discloses an intake manifold of a V-type 6-cylinder internal combustion engine which is composed of divided constituent members and in which blow-by gas passages are formed in the constituent members. This intake manifold
A lower block, an intermediate block, and an upper block are sequentially stacked, and two surge tanks are formed by the intermediate block and the upper block. Three branch pipes connected to each surge tank are a lower block and an intermediate block. Is formed by. 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 blow-by gas passage is formed in each joint surface of the lower block and the intermediate block, and the blow-out port that connects the blow-by gas passage and each branch pipe is formed in the lower block.

[0003]

By the way, in the case where the intake manifold is composed of divided constituent members (blocks), the airtightness at the dividing surface (joint surface) of each constituent member is considered from the viewpoint of preventing leakage of intake air. A seal member is used to increase the temperature. Then, in the case where the blow-by gas passage is formed in each joint surface of the lower block and the intermediate block as in the above-mentioned conventional technique, it is necessary to secure a sealing surface for additionally sealing the blow-by gas passage. Therefore, since the width of the dividing surface is larger than that of the intake manifold in which the blow-by gas passage is not formed in the dividing surface, there is a problem that the intake manifold becomes larger when viewed from the dividing surface, and the size is increased. If this is attempted to be suppressed, restrictions will be placed on the arrangement and shape of the intake passage in the intake manifold, reducing the degree of freedom in designing the intake passage. Further, at the time of cryogenic start after the operation of the internal combustion engine is temporarily stopped, the water in the blow-by gas passage or the water in the blow-by gas may be frozen and the blow-by gas passage may be closed. However, no measures for that have been disclosed.

The present invention has been made in view of such circumstances, and the inventions according to claims 1 to 3 are:
In an intake manifold having a blow-by gas passage formed by using a dividing surface, a seal member prevents leakage of intake air and blow-by gas at the dividing surface, suppresses the intake manifold from increasing in size, and mounts a sealing member. The purpose is to facilitate the work. The invention according to claim 2 further aims to prevent the blow-by gas passage from being closed due to freezing of the water in the blow-by gas passage or the water in the blow-by gas.
The invention according to claim 3 further aims to increase the degree of freedom in arrangement and shape setting of the intake passage.

[0005]

According to a first aspect of the present invention, there is provided an intake manifold having a predetermined number of intake passages, which communicate with combustion chambers corresponding to a predetermined number of cylinders. In an intake manifold of a multi-cylinder internal combustion engine, which is composed of divided constituent members including a second member, and in which a blow-by gas passage is formed in the first member, the intake passage is formed by the first member and the second member. A seal groove formed of a first groove surrounding all the intake passages and a second groove located inside the first groove is formed on a dividing surface of the first member with respect to the second member. And a third groove having a first opening opening to each of the intake passages is formed on a bottom wall surface of the second groove, and the seal groove is attached to the first groove to form the first member. Between the second member A first sealing portion of the endless keeping airtight,
A seal member integrally formed with a second seal portion that is mounted in the second groove is mounted, and the blow-by gas passage is
The second seal portion is formed by hermetically covering the third groove, and the first opening portion is an intake manifold of a multi-cylinder internal combustion engine that forms an outlet portion of blow-by gas to the intake passage.

According to the invention described in claim 1, the following effects are exhibited. That is, between the first member and the second member that form the predetermined number of intake passages, the endless first seal portion is attached to the first groove that surrounds all the intake passages, so that airtightness is maintained. Moreover, the blow-by gas passage is formed in the third wall formed on the bottom wall surface of the second groove formed inside the first groove.
Since the groove is airtightly covered and formed by the second seal member attached to the second groove, the seal surface of the blow-by gas passage can be formed by the wall surface of the second groove. The width of the dividing surface can be made smaller than that in which the sealing surface is formed on the dividing surface, and the intake manifold can be prevented from becoming large due to the formation of the blow-by gas passage. Furthermore, since the first seal portion and the second seal portion are integrally formed, the work of mounting the seal member for ensuring the airtightness between the first member and the second member and the airtightness of the blow-by gas passage is facilitated. Become.

According to a second aspect of the present invention, in the intake manifold for a multi-cylinder internal combustion engine according to the first aspect, the seal member is made of a heat insulating material having a thermal conductivity smaller than that of the material forming the first member. It is a thing.

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, since the seal member is formed of a heat insulating material, the thermal conductivity of the second seal portion forming the blow-by gas passage is the first when the internal combustion engine is started at a very low temperature after the operation is temporarily stopped. Since it is smaller than the forming material of one member, the heat-retained state is maintained for a while in the blow-by gas passage, so that the water in the blow-by gas passage and the water in the blow-by gas are prevented from freezing during that time. As a result, during cryogenic start after the operation of the internal combustion engine is temporarily stopped, the blockage of the blow-by gas passage due to frozen water is suppressed, and the blow-by gas can be normally returned to the intake manifold immediately after the start. .

According to a third aspect of the present invention, in the intake manifold of the multi-cylinder internal combustion engine according to the first or second aspect, the second seal portion is in airtight contact with the second member,
The second groove has a second opening that opens into each of the intake passages, and at the second opening, a part of the second seal portion forms a passage wall surface of the intake passage, and the passage wall surface is The wall surface of the intake passage formed by the first member is substantially smoothly continuous.

According to the invention of claim 3, in addition to the effects of the invention of the cited claim, the following effects are exhibited. That is, since the passage wall surface of the intake passage formed by a part of the second seal portion is substantially smoothly continuous with the passage wall surface of the intake passage formed by the first member, the second seal portion is exposed in the intake passage. It is possible to prevent the passage wall surface of the intake passage from becoming discontinuous at a portion and forming a concave portion or a convex portion that disturbs the flow of the intake air on the passage wall surface as much as possible. The decrease can be suppressed. Moreover, since the width of the second groove can be reduced at the portion where the intake passage is formed, that is, the width of the dividing surface at that portion can be reduced, the intake manifold due to the formation of the blow-by gas passage can be reduced. Since it is possible to further suppress the increase in size and use the portion of the second groove in which the second seal portion is mounted for forming the intake passage, the degree of freedom in arrangement and shape setting of the intake passage is increased.

[0011]

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 rotation axis 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 is rotatably supported by the cylinder block 1 via a connecting rod and rotationally drives the crankshaft housed in the crank chamber. . In the cylinder head 3, for each cylinder 2, a combustion chamber 6 formed of a concave portion formed at a position facing the cylinder hole 2a, an intake port 7 having a pair of intake valve openings 7a opening to the combustion chamber 6, Exhaust port 8 having a pair of exhaust valve ports 8a opening to the combustion chamber 6
And a pair of intake valves 9 and 1 that are driven by the valve operating device in synchronization with the crankshaft to open and close both intake valve openings 7a and exhaust valve openings 8a at predetermined timings. Exhaust valve 10 is 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).

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 molded 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.

As shown in FIG. 1, the outer member M1 is
The horizontal dividing surface D1 vertically divides the lower outer member 30 and the upper outer member 40 into two parts. Then, the lower outer member 30 and the upper outer member 40 are coupled by a plurality of bolts (not shown), and the lower outer member 30 has a plurality of bolts (not shown) at its left and right flange portions 30a. Combined with 3. Meanwhile, the inner member M2
Is vertically divided into a pair of lower inner member 50 and a pair of upper inner member 60 by a dividing surface D2 that is on the same plane as the dividing surface D1. The dividing surface D1 is a lower outer member.
30-side dividing surface D1L and upper outer member 40-side dividing surface D1U
The dividing surface D2 is a lower inner member 50.
The divided surface D2L on the side and the divided surface D2U on the upper inner member 60 side are collectively referred to.

The lower outer member 30 has both end walls 31 and 32 in the axial direction A and a peripheral wall 33 curved so as to be convex downward, and a part of these walls 31 to 33 is used as a passage wall. 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.
Then, on 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 seats 35.
Between the end wall 31 and the end wall 31 or the end wall 32, a groove 36 formed by forming a part of the peripheral wall 33 as the outer wall 34 of the first passage P1 curved in a J shape when viewed from the axial direction A is formed. The outer portion is formed.

In the flange portion 30a 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 openings 7a is attached to the attachment hole 30b. Further, the exhaust gas introducing pipe 15 is coupled to the end wall 32. The exhaust introduction pipe 15 recirculates the exhaust gas taken out from the exhaust system including the exhaust port 8 and the exhaust manifold to the intake system as EGR gas (recirculation exhaust gas) to perform exhaust gas recirculation (EGR),
The EGR gas whose flow rate is controlled by the EGR control valve is guided to the intake manifold M. For that, the end wall
A pair of outlet pipes 15b of the exhaust introduction pipe 15 inserted from the opening 37a of the mounting portion 37 are fitted to the pair of left and right passage forming portions 52 near 32, and the inlet pipe 15a of the exhaust introduction pipe 15 is Entrance 15a1 (Fig. 4
The EGR gas flowing in from the center opening portion 56b flows out to the center portion 20a of the intake collecting chamber 20 through the passage 56.

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.
(Therefore, the center point CT (center plane CP1 when viewed from the split surface D1L in plan view of the lower outer member 30) with the center plane CP1 located at 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 an intersection line with CP2 and an intersection of a plane including the division surface D1L) and is coupled 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. Consists of. Accordingly, the lower outer member 30 and the lower inner member in each first passage P1
A dividing surface of the intake passage 21 along the first passage P1 and a center line N of the intake passage 21 (long intake passage 22) when viewed from the axial direction A.
V1 (see FIG. 1) is configured 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.

On the other hand, the upper outer member 40 has a central portion in the axial direction A and the left-right direction of the intake collecting chamber 20 for the intake air introduced from the outer end walls 41 and 42 in the axial direction A and the intake inflow portion 45 described later. It has a pair of inner end walls 43 facing each other with a communication passage 46 interposed therebetween for guiding to the 20a, and a peripheral wall 44 curved so as to be convex upward, and a part of these walls 41 to 44 is formed as a passage wall. As intake passage
The second passage P2 which is a part of 21 and the intake wall 45 is formed by a part of the peripheral wall 44. Specifically, the central portion of the peripheral wall 44 in the axial direction A passes through the center plane CP2 and the center plane CP2.
An intake air inflow portion 45 is formed along which the inflow passage 45a is formed. The throttle base 12 made of aluminum alloy is coupled to the connecting portion 45b which is provided on the right side which is one of the left and right directions of the intake inflow portion 45 and which forms the inlet portion 45A of the inflow passage 45a. A throttle body 13 having a throttle valve 11 mounted thereon is coupled to 12 (see FIG. 1). 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, on the peripheral wall 44, partition walls 47 having side walls 47a facing the axial direction A are formed, and between the partition walls 47 adjacent to each other in the axial direction A, and between the partition wall 47 and the outer end wall 41, Between the inner wall 42 and the inner end wall 43, a groove 49 formed by forming a part of the peripheral wall 44 as an outer wall 48 forms a second passage P2 that is curved so as to be convex upward when viewed in the axial direction A. The outer portion is formed.

The outer end wall 41 of the upper outer member 40,
42 is a negative pressure type actuator that drives the intake control valve 24.
The bracket 90 to which 91 is attached is connected. The actuator 91 includes a link / lever mechanism 93 arranged in the intake collecting chamber 20 by a rod 92 connected to the diaphragm.
The two operation shafts 94 rotatably supported by the body 97 of the valve unit 95 described later are rotated via the Opening and closing are performed simultaneously according to the engine 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, the center plane The center point of the upper outer member 40 when viewed from the dividing surface D1U 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). They are arranged in point symmetry with respect to an intersection with a plane including D1) and are 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 having a circular opening and connected to an air funnel 96 described later 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 41, 42 of the upper outer member 40.
And the step portions 41a, 42a, 43a of the inner end wall 43 and the step portion 47a1 (see FIG. 1) of the partition wall 47. Where the step
41a, 42a, 43a are stepped bulges 41b, 42b formed by bulging the end walls 41, 42, 43 outward in the axial direction A.
The stepped portion 47a1 is formed of 43b, and the stepped portion 47a1 is formed by a stepped bulged portion 47b formed by bulging the side wall 47a outward in the axial direction A. As a result, the upper outer member 40 and the upper inner member 60 in each second passage P2
The dividing surface V2 along the passage P2 is formed by the mating surface of the fitting portion H2. Therefore, on the dividing surface V2, the outer end wall 41,
42, the inner end wall 43 and the partition wall 47, and the partition wall 64 are in surface contact with each other, so that the leakage of intake air is suppressed and the airtightness is secured.

Further, a valve unit 95 is housed in a 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.

By the way, referring to FIG. 4, in the dividing surface D1L of the lower outer member 30, a part of which also serves as a mating surface with the upper inner member 60, the first groove 71, the second groove 72 and the first and second grooves 71, 72 are formed.
A seal groove composed of a plurality of communication grooves 73 that communicate between the grooves 71 and 72.
70 is formed, and the seal member 80 (see FIG. 5) is mounted in the seal groove 70.

A first groove 71 having a groove width substantially uniform over the entire circumference.
Surrounds the first and third passages P1 and P3, which are a part of the eight intake passages 21, and the intake collecting chamber 20 in the dividing surface D1L, and at the same time, the mounting hole 30b of the fuel injection valve 14 and the third passage P3. Extends through the space. The second groove 72 is located inside the first groove 71, and on the left and right side portions of the lower outer member 30, the third passage P3 and the first passage P3 that are located outside the first passage P1 in the left-right direction. A pair of first members extending in the axial direction A between the first passage and the passage P1.
It comprises a portion 72a and a second portion 72b formed on the end wall 32 so as to connect the first portions 72a with each other. Each first portion 72a has a uniform groove width, except for a portion of an opening 72c described later. A part of the communication groove 73 having a groove width smaller than the groove widths of the first and second grooves 71 and 72 is provided with respect to the first groove 71 and each first portion 72a that sandwich each third passage P3. The first groove 71, the first portion 72a, and the communication groove 73 are formed so as to surround the third passage P3.

Further, the second groove 72 has an opening 72c which is a notch opening to the first passage P1 and the third passage P3,
In the portion having the opening 72c, the first passage P1 and the third passage P1
The second groove 72 is scooped out to form the passage P3, and the groove width is narrower than the other portions.

The bottom wall surface 75a of the second groove 72 (see FIGS. 6-8)
In the reference), a third groove 74 having a groove width smaller than that of the second groove 72 is formed along the second groove 72. The third groove 74 is
An opening 72c and an opening 74a formed by a notch opening to the third passage P3 are provided at a position facing the mounting hole 30b across the third passage P3.

Referring to FIG. 5, the seal member 80 is a first
The endless first seal portion 81 mounted in the groove 71, the second seal portion 82 mounted in the second groove 72, the first seal portion 81 and the second seal portion 82 are connected to each communication groove 73. A large number of connecting parts 83 to be mounted are integrally molded. Seal member 80
Is made of a heat insulating elastic material, for example, synthetic rubber such as silicon rubber, and has a smaller thermal conductivity and a larger specific heat than the material forming the lower outer member 30.

Further referring to FIG. 6, FIG. 9 and FIG. 10 together, the first seal portion 81, as shown in FIG. 9, has the first groove in the natural state before being mounted in the seal groove 70. It has a sectional shape protruding from 71. The second seal portion 82 is further referred to FIG. 7 and FIG. 8, and the dividing surface D2U of the upper inner member 60 is shown.
Corresponding to the flat top surface 82a that comes into surface contact with, the bottom surface 82b that comes into surface contact with the flat bottom wall surface 75a of the second groove 72, and the opening 72c of the second groove 72 when mounted in the second groove 72. And a side surface 82c that forms a recessed portion 82d that is hollowed out. Then, in the portion of the second seal portion 82 that is mounted in each of the first portions 72a of the second groove 72, a ridge 82e that partially fits into the third groove 74 is formed, and as shown in FIG. As described above, beads 8 are formed on the top surface 82a and the bottom surface 82b to increase airtightness.
2f is formed. The second seal portion 82 is slightly smaller than the second groove 72 in a natural state before being mounted in order to suppress the elastic deformation amount when the lower outer member 30 and the upper inner member 60 are coupled as much as possible. Has a large cross-sectional shape,
The width e is slightly larger than the groove width of the third groove 74. Furthermore, the area of the cross section of the second seal portion 82 is set to be larger than the passage area of the third groove 74 (see FIGS. 6 and 10).
Further, each connecting portion 83 is mounted in the corresponding communication groove 73.

Then, the seal member 80 is mounted in the seal groove 70, and the lower inner member 50 is joined to the lower outer member.
30 and the upper outer member 40 in which the upper inner member 60 is joined.
When the and are coupled by the bolts, as shown in FIG. 6, the first seal portion 81 is elastically deformed so as to fill up the first groove 71, so that the space between the lower outer member 30 and the upper outer member 40 is reduced. Keep airtight. The second seal portion 82 is an upper inner member.
When the bead 82f is completely crushed by being pressed by the 60, the whole is slightly elastically deformed and the upper inner member 60
Partition surface D2U and the bottom wall surface 75a and the side wall surface 75 of the second groove 72
touch b. The airtightness of the second seal portion 82 is enhanced by the bead 82f being crushed by the dividing surface D2U and the bottom wall surface 75a, and the ridge 82e being fitted in the third groove 74. In this way, the second seal portion
The blow-by gas passage 76 is formed by 82 airtightly covering the third groove 74, and the blow-by gas outlet portion 76a to each intake passage is formed by the opening 74a. Further, the connecting portion 83 contacts the dividing surface D1L of the lower outer member 30 and the dividing surface D1U of the upper outer member 40 to maintain the airtightness between the outer members 30, 40.

Further, as shown in FIG. 6, when the lower outer member 30 and the upper outer member 40 are joined, the second seal portion 82 has a recess 82d of the second seal portion 82 in the opening 72c. A passage wall surface Ws of the intake passage 21 is formed. At this time, since the second seal portion 82 has a cross-sectional shape slightly larger than the second groove 72 in a natural state, the degree of elastic deformation of the second seal portion 82 is also small, and the passage wall surface Ws is formed by the lower outer member 30. The second passage of the intake passage 21 formed by the upper outer member 40 and the upper inner member 60 becomes a passage wall surface that is substantially smoothly continuous with the passage wall surface Wb of the first and third passages P1, P3 of the intake passage 21. The passage wall surface Wb of P2 is a passage wall surface that is almost smoothly continuous.

Further, on the dividing surface U1L, each third passage P3 is
It is surrounded by the first seal portion 81, the second seal portion 82, and the two connecting portions 83, and is airtightly divided for each third passage P3.

On the other hand, referring to FIG. 4, the upper outer member
The inlet portion 77 of the blow-by gas to which the pipe joint 84 (see also FIG. 3) attached to the 40 is airtightly connected is the first groove of the third groove 74.
At the intersection of the portion 72a and the second portion 72b, the split surface U1L of the lower outer member 30 is formed so as to communicate with the third groove 74. Then, the pipe joint 84, via the external passage formed by the rubber hose 85, the pipe 86 and the rubber hose 87,
The lower outer member 30 communicates with a PCV valve (not shown) mounted on a mounting portion 88 formed of a through hole formed in the left flange portion 30a, and the PCV valve is connected to the cylinder head 3 of the lower outer member 30. The connecting passage 89 (see also FIG. 8) formed by the groove formed on the mating surface communicates with the crank chamber through an internal passage (not shown) formed in the cylinder head 3 and the cylinder block 1.

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.

The blow-by gas, which is the unburned air-fuel mixture leaked from the sliding portion between the cylinder 2 and the piston 5, is discharged from the crank chamber into the internal passage, the connecting passage 89, and the P passage.
It flows into the inlet portion 77 through the CV valve, the external passage and the pipe joint 84, passes through the blow-by gas passage 76, and the outlet portion 76.
It flows from a into the intake passage 21 and is supplied to the combustion chamber 6 together with fresh air.

Here, of the outer member M1 and the inner member M2 forming the eight intake passages 21, the lower outer member 30
Between the upper outer member 40 and the upper inner member 60,
On the dividing surface D1L, a first groove that surrounds all of the first passage P1 and the third passage P3 that are a part of the intake passage 21 and the intake collecting chamber 20.
The endless first seal portion 81 is attached to 71 to keep airtightness, and the second seal portion 82 is attached to the second groove 72 to keep airtightness further. Moreover, the blow-by gas passage 76 has the second groove formed inside the first groove 71.
The third groove 74 formed on the bottom wall surface 75a of the 72 is airtightly covered by the second seal portion 82 mounted on the second groove 72, so that the sealing surface of the blow-by gas passage 76 is Since it can be formed by the bottom wall surface 75a and the bottom wall surface 75b of the two grooves 72, the width of the dividing surface U1L can be made smaller than that in which the dividing surface U1L is the sealing surface of the blow-by gas passage 76. It is possible to prevent the intake manifold M from increasing in size due to the formation of the blow-by gas passage 76. Further, since the first seal portion 81 and the second seal portion 82 are connected by the connecting portion 83 and integrally formed, the airtightness between the lower outer member 30 and the upper outer member 40 and the upper inner member 60 is achieved. And blow-by gas passage 76
The work of mounting the seal member 80 for ensuring the airtightness of the device becomes easy.

On the dividing surface U1L of the lower outer member 30, the outlet portion 76a of the blow-by gas passage 76 has the third passage P1.
Since it is located at a portion facing the mounting hole 30b in which the fuel injection valve 14 is mounted with the fuel cell interposed therebetween, the oil mist contained in the blow-by gas is prevented from adhering to the fuel injection valve 14. Furthermore, on the dividing surface U1L, each third passage P
3 is a first seal portion 81, a second seal portion 82, and two connecting portions 8
Since it is surrounded by 3 and is airtightly divided for each third passage P3, leakage of intake air between adjacent intake passages 21 and between the intake passages 21 and the intake collecting chamber 20 is prevented.

Since the seal member 80 is formed of a heat insulating material, the second seal portion 82 forming the blow-by gas passage 76 is formed at a very low temperature start after the operation of the internal combustion engine E is temporarily stopped. Since the thermal conductivity is smaller than that of the light metal material or the alloy thereof, which is the forming material of the lower outer member 30, the heat-retained state is maintained for a while in the blow-by gas passage 76. Water in the blow-by gas is prevented from freezing. As a result, during cryogenic start after the operation of the internal combustion engine E is temporarily stopped, the blockage of the blow-by gas passage 76 due to frozen water (ice) is suppressed, and the reduction of blow-by gas to the intake manifold M immediately after the start is suppressed. It can be done normally. Further, since the specific heat of the second seal portion 82 is larger than that of the material forming the lower outer member 30, the heat retaining state of the blow-by gas passage 76 is maintained longer.

Intake passage formed by a part of the second seal portion 82
The passage wall surface Ws of 21 is substantially smoothly continuous with the passage wall surfaces Wb of the first and third passages P1 and P3 that are a part of the intake passage 21 formed by the lower outer member 30, so that the sealing member 80
Since it is possible to prevent the passage wall surface of the intake passage 21 from becoming discontinuous at the portion where is exposed to the intake passage 21 and forming a concave portion or a convex portion that disturbs the flow of the intake air on the passage wall surface as much as possible, It is possible to suppress a decrease in volumetric efficiency due to an increase in pressure loss. Moreover, it is possible to reduce the groove width of the second groove 72 at the opening 72c and the recess 82d in which the first and third passages P1 and P3 are formed, that is, to reduce the width of the dividing surface D1L at that portion. Therefore, it is possible to further suppress the increase in the size of the intake manifold M due to the formation of the blow-by gas passage 76, and to further install the second seal portion 82 in the second groove.
Since the portion 72 can be used for forming the intake passage 21, the degree of freedom in arrangement and shape setting of the intake passage 21 is increased.

In particular, the opening 7 of each first portion 72a of the second groove 72
Since 2c is scooped corresponding to the passage wall surface Wb of the third passage P3 and the groove width of the first portion 72a is narrowed, the width of the intake manifold M in the left-right direction is reduced accordingly. , The intake manifold M can be compactly arranged in the space S formed by both banks BL and BR, and the internal combustion engine E can be miniaturized. Further, the first portion 72a of the second groove 72
In the intake manifold M in which the first passage P1 and the third passage P3 are opposed to each other with the first passage P1 and the third passage P3 interposed therebetween, the opening 72c of each first portion 72a is formed in the passage wall surface Wb of the first and third passages P1, P2. Since it is formed with a correspondingly recessed recess 82d, the split surface U1L
Above, the first passage P1 and the third passage P3 can be arranged closer to each other in the left-right direction, and the width of the intake manifold M in the left-right direction can be further reduced.

The outlet portion 76a of the blow-by gas passage 76 is opened to the opening 72c, and the second seal portion 82 is formed in the portion forming the passage wall surface Ws of the third passage P3. Since a part is formed by the second seal portion 82 made of a heat insulating material, heat retention is also obtained at the outlet portion 76a, so that the outlet portion 76a is prevented from being blocked by freezing of water.

In the following, an embodiment in which a part of the structure of the above-mentioned embodiment is modified will be described.
The seal groove 70 is formed on the dividing surface D1L of the lower outer member 30 in the above embodiment, but when the upper outer member 40 and the upper inner member 60 are integrally molded as the upper component, the seal groove 70 is It may be formed on the dividing surface.

In the above embodiment, each intake passage 21 is composed of a long intake passage 22 and a short intake passage 23 that are switched according to the engine speed, but each intake passage has a single intake passage. It may be constituted by a passage. Further, the internal combustion engine 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 manifold of 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 the intake manifold 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.

FIG. 5 is a plan view of the seal member in a state where the seal member is mounted in a seal groove formed on a divided surface of the lower outer member of FIG.

FIG. 6 is an enlarged view of a main part of FIG.

7 is a cross-sectional view taken along the line VII-VII of FIG.

8 is a sectional view taken along line VIII-VIII in FIG.

9 is a cross-sectional view of the seal member in a natural state at a portion corresponding to line IX-IX in FIG.

10 is a cross-sectional view of the seal member in a natural state at a portion corresponding to line XX in FIG.

[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, 15 ... Exhaust gas introduction pipe,
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 portion,
37a ... Opening part, 40 ... Upper outer member, 41-43 ... End wall, 4
4 ... Circumferential wall, 45 ... Intake inflow part, 46 ... Communication passage, 47 ... Partition wall, 4
8 ... 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, 60 ... Upper inner member, 61 ... Intake passage forming part, 62 ... Storage part, 63 ... Inner wall, 64 ... Partition wall, 65 ... Groove, 66
... Connection part, 70 ... Seal groove, 71 ... First groove, 72 ... Second groove, 73
... communication groove, 74 ... third groove, 74a ... opening, 75a ... bottom wall surface, 75
b ... Side wall surface, 76 ... Blow-by gas passage, 76a ... Exit portion, 77
... Inlet part, 80 ... Seal member, 81 ... First seal part, 82 ... Second seal part, 82d ... Recessed part, 83 ... Connection part, 84 ... Pipe fitting, 8
5, 87 ... rubber hose, 86 ... pipe, 88 ... mounting part, 89 ... connection 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 to P3… Passage, CP
1, CP2 ... Center plane, CT ... Center point, H1, H2 ... Fitting section, T ... Groove section, Wb, Ws ... Passage wall surface.

Claims (3)

[Claims] 1. An intake manifold having a predetermined number of intake passages, each of which communicates with a combustion chamber corresponding to a predetermined number of cylinders, is composed of a divided component member including a first member and a second member. In an intake manifold of a multi-cylinder internal combustion engine in which a blow-by gas passage is formed in a first member, the intake passage is formed by the first member and the second member, and is formed on a dividing surface of the first member with respect to the second member. Has a seal groove formed of a first groove that surrounds all the intake passages and a second groove that is located inside the first groove. The seal groove is formed on the bottom wall surface of the second groove in each of the intake passages. A third groove having a first opening that opens is formed, and the seal groove is attached to the first groove to connect the first member and the second member.
A seal member integrally formed with an endless first seal portion for keeping airtight between the member and a second seal portion mounted in the second groove is mounted, and the blow-by gas passage is provided with the second seal. An intake manifold for a multi-cylinder internal combustion engine, wherein a portion is formed by airtightly covering the third groove, and the first opening portion forms an outlet portion of blow-by gas to the intake passage. 2. The intake manifold for a multi-cylinder internal combustion engine according to claim 1, wherein the seal member is made of a heat insulating material having a thermal conductivity smaller than that of the material forming the first member. 3. The second seal portion is in airtight contact with the second member, and the second groove has a second opening opening to each of the intake passages, and the second opening has the second opening. 2. A part of the second seal portion forms a passage wall surface of the intake passage, and the passage wall surface is substantially smoothly continuous with the passage wall surface of the intake passage formed by the first member. An intake manifold for a multi-cylinder internal combustion engine according to claim 2.