JPH0214977B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Industrial Application Field The present invention relates to an intake manifold of a V-type internal combustion engine;
In particular, a first block is arranged in a valley between a pair of cylinder rows arranged in a V-shape and has a plurality of intake passages connected to the intake ports of each cylinder row; a second block connected by a substantially right-angled joint surface and disposed on the outside of the valley and having a common intake distribution chamber connected to the upstream ends of the plurality of intake passages; , a pair of mounting flanges respectively connected to both cylinder rows are integrally formed, and a plurality of intake passages corresponding to one cylinder row of the first block are connected to a plurality of intake passages corresponding to the other cylinder row. The plurality of intake passages corresponding to the one cylinder row are arranged offset from each other by a certain distance in the axial direction of the crankshaft with respect to the one cylinder row, and the mounting flange corresponding to the one cylinder row is arranged with respect to the other mounting flange. This invention relates to an improvement in an intake manifold arranged in an offset manner in the same manner as in the above.

(2) Prior art This intake manifold is disclosed in Japanese Patent Application Laid-Open No. 60-69254.
It is disclosed in the publication No.

(3) Problems to be Solved by the Invention In the conventional intake manifold, the joint surface of the first block can be finished without being interfered with by the pair of mounting flanges. Since the first block was disposed further outward from the outermost end, the length of the intake passage of the first block was restricted by the joint surface, and even if an attempt was made to make the intake passage short, there was a limit.

The present invention has been made in view of the above circumstances, and provides an intake manifold in which the joining surface of the first block can be easily finished and the length of the intake passage can be shortened. The purpose is to

B. Structure of the invention (1) Means for solving the problems In order to achieve the above object, according to the present invention,
A first block is arranged in a valley between a pair of cylinder rows arranged in a V-shape and has a plurality of intake passages connected to the intake ports of each cylinder row; a second block connected by a right-angled joint surface and disposed on the outside of the valley and having a common intake distribution chamber connected to the upstream ends of the plurality of intake passages; the first block includes: A pair of mounting flanges each connected to both cylinder rows are integrally formed, and the first
The plurality of intake passages corresponding to one cylinder row of the block are arranged to be offset by a certain distance in the axial direction of the crankshaft with respect to the plurality of intake passages corresponding to the other cylinder row. In an intake manifold for a V-type internal combustion engine, the corresponding mounting flange is arranged offset with respect to the other mounting flange in the same manner as the plurality of intake passages corresponding to the one cylinder row. The joint surface is located between one ends of the same side of both the mounting flanges in the offset direction of the two mounting flanges, one end of which protrudes outward in the crankshaft direction beyond the joint surface, and the other end thereof. The portion is arranged so that the portion is located inward in the crankshaft direction from the joint surface.

(2) Effect According to the above configuration, when finishing the joint surface of the first block, only one end of the one mounting flange that protrudes outward from the joint surface needs to be placed outside the movement trajectory of the tool. For example, the joint surface can be machined all at once with the same tool without being interfered with by the other mounting flange.

Moreover, the above-mentioned joint surface can be placed inward in the crankshaft direction from the above-mentioned one end of one mounting flange without impairing the finish workability thereof, and each mounting flange and its corresponding Offset the intake passage in the same way,
The synergistic effect of minimizing the amount of overhang of the one end of each mounting flange toward the second block side makes it possible to deviate the joint surface inward in the crankshaft direction as much as possible. Therefore, it is possible to contribute to shortening the intake passage in the first block, and it is also possible to suppress the amount of protrusion of the second block joined to the joint surface to the outside of the valley as much as possible.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

The internal combustion engine shown in Fig. 1 is a V-type six-cylinder engine, so two
Each cylinder row C, C' has three cylinders 1, 1' arranged in the axial direction (front and back direction in FIG. 1) of a crankshaft (not shown).

Since the structures of both cylinder rows C and C' are approximately symmetrical, the structure of the left cylinder row C will be mainly explained.A cylinder head 3 is attached to the upper surface of the cylinder block 2 in which the cylinder 1 is formed via a gasket 4. Polymerized and bonded. A piston 5 is slidably fitted into the cylinder 1, and a combustion chamber 6 is recessed in the bottom surface of the cylinder head 3 facing the piston 5.

The ceiling surface 7 of the combustion chamber 6 is made up of two slopes 7a and 7b descending from a ridge line L extending in the direction in which the three cylinders 1 are arranged (see FIG. 1A) to both the left and right sides. A pair of intake valve ports 8, 8 are provided on the slope 7a located on the valley V side between C', and a pair of exhaust valve ports 9, 9 are provided on the opposite slope 7b.
are lined up and open along the ridge line L, and these intake valve ports 8, 8 and exhaust valve ports 9, 9 are connected to the valve mechanism 1.
They are opened and closed by each pair of intake valves 11, 11 and exhaust valves 12, 12, which are driven by the valve 0.
One spark plug 13 surrounded by these four valves 11, 11; 12, 12 is screwed onto the cylinder head 3, and its electrode faces the center of the ceiling surface 7 of the combustion chamber 6.

Each pair of intake valve ports 8, 8 and exhaust valve ports 9, 9
are connected to the common intake port 14 and exhaust port 15, respectively, and the entrance of the intake port 14 is connected to the valley V
The exhaust port 15 opens at the upper surface of one side of the cylinder head 3 adjacent to the cylinder head 3, and the outlet of the exhaust port 15 opens at the other side of the cylinder head 3.

In Fig. 2, the three intake ports in the left cylinder row C are called the first, second, and third left intake ports 14 ₁ , 14 ₂ , and 14 ₃ in order from above, and the three intake ports in the right cylinder row C' Similarly, from the top, the first, second and third intake ports on the right side 14 ₁ ', 14
We will call them ₂ ′, 14 ₃ ′. The left side first to third intake port groups ₁₄₁ to ₁₄₃ and the right side first to third intake port groups ₁₄₁ ' to ₁₄₃ ' refer to the left side cylinder row C.
Similar to the relationship between cylinder group 1 and cylinder group 1' of right cylinder row C', they are arranged offset from each other by a certain distance ε in the axial direction of the crankshaft, and this offset amount ε is Column C
This corresponds to the amount of offset between the connecting rods of the right cylinder row C' system and the connecting rods of the right cylinder row C' system, which are caused by connecting them adjacent to each other to a common crank pin of the crankshaft.

The above intake ports 14 ₁ , 14 ₂ , 14 ₃ ; 14 ₁ ',
An intake manifold M is disposed through the valley V for distributing and supplying air or air-fuel mixture to 14 ₂ ′ and 14 ₃ ′. As shown in FIGS. 2 to 7, this intake manifold M includes one common intake distribution chamber 16 and first to third left intake ports 14 ₁ extending from one side of this distribution chamber 16. 14 ₃ respectively, and the left first to third high speed intake passages 17 ₁ to 17 ₃ extending from the other side of the intake distribution chamber 16 to the left side.
The first to third low-speed air intake paths 18 ₁ to 18 ₃ on the left side are connected to the branch ports b ₁ to b ₃ provided in the intermediate portions of the air intake paths 17 ₁ to 17 ₃ , respectively, and from one side of the air intake distribution chamber 16. Extending right side first to third intake ports 14 ₁ ′ to 1
4 ₃ ′ right side first to third high-speed intake passages 1
7 ₁ ′ to 17 ₃ ′ and branch ports b ₁ ′ to _{b 3} extending from the other side of the air intake distribution chamber 16 and provided in the intermediate portions of the right first to third intake passages 17 ₁ ′ to _{17 3} ′. The first to third right-side low-speed intake passages 18 ₁ ′ to 18 ₃ ′ are connected to the right side, respectively.

In addition, the intake manifold M has a first block B ₁ disposed in the valley V and a third intake port 1 in the valley V in order to facilitate its processing, assembly, maintenance, etc.
4 ₃ , 14 ₃ 'Second block disposed on the outside side
B ₂ and an intermediate plate P interposed between both blocks B ₁ and B ₂ , and these dividing surfaces, in other words, the joining surfaces F ₁ and F ₂ are approximately perpendicular to the axis of the crankshaft. It is formed. The first block B ₁ has a pair of horizontal mounting flanges 1 corresponding to the left and right cylinder rows C and C'.
9, 19' are integrally formed, and both mounting flanges 19, 19' are connected to the left side first to third intake ports ₁₄₁ to ₁₄₃ group and the right side first to third intake ports 14.
In accordance with the above-mentioned relationship with _{the 1} ' to ₁₄₃ ' groups, it is offset by a certain distance ε in the axial direction of the crankshaft.

Thus, the joint surface F ₁ of the first block B ₁ is arranged between the ends 19e, 19e' on the same side of both the mounting flanges 19, 19' in the offset direction of the mounting flanges 19, 19'. . Moreover, at that time,
One end 19e protrudes outward in the crankshaft direction from the joint surface _F1 , and the other end 19
The position of the joint surface F ₁ is determined so that e′ is located inward in the crankshaft direction than the joint surface F ₁ . Both mounting flanges 19, 19' are fixed to the cylinder heads 3, 3' of each cylinder row C, C' via a plurality of bolts 20, 20', respectively.

Also, connecting flanges 21 and 22 are integrally formed at opposite ends of the first and second blocks B ₁ and B ₂ , respectively, and both connecting flanges 21 and 22 are connected by a plurality of bolts 23 with an intermediate plate P in between. mutually bound.

The intake air distribution chamber 16 has a basic shape of a cylinder longer than the maximum width of the valley V, and is formed in the second block _B2 so as to face in a horizontal direction perpendicular to a crankshaft (not shown). The first high-speed intake passages 17 ₁ , 17 ₁ ′ connected to the first intake ports 14 ₁ , 14 ₁ ′ which are farthest from the intake air distribution chamber 16 are arranged left and right in the center of the valley V, and are connected to the first block B ₁ . The first low-speed intake passages 18 ₁ , 18 ₁ ′ are located below the corresponding first high-speed intake passages 17 ₁ , 17 ₁ ′ in the first block B ₁ , and open into the intake distribution chamber 16 through the intermediate plate P. Pass by the side,
After passing through the intermediate plate P, it is reversed upward from the lower side of the air intake distribution chamber 16 and opens at the upper surface of the chamber 16 . Further, the second high-speed intake passages 17 ₂ , 17 ₂ ′ are arranged left and right in the center of the valley V, pass through the upper part of the first high-speed intake passages 17 ₁ , 17 ₁ ′ in the first block B ₁ , and pass through the intermediate plate P. The second low-speed intake passages 18 ₂ , 18 ₂ ′ pass through the upper side of the corresponding second high-speed intake passages 17 ₂ , 17 ₂ ′ in the first block B ₁ , and open into the intake distribution chamber 16 . After passing through the air intake distribution chamber 16
The chamber 16 is opened at the lower surface by inverting from the upper side to the lower side. Further, the third high-speed intake passages 17 ₃ , 17 ₃ ′ pass through the first block B ₁ adjacent to the left and right sides of the second high-speed intake passages 17 ₂ , 17 ₂ ′, pass through the intermediate plate P, and enter the intake distribution chamber 16 . the third low-speed intake passage 18 ₃ ,
18 ₃ ′ passes above the corresponding third high-speed intake passages 17 ₃ , 17 ₃ ′ in the first block B ₁ and connects to the intermediate plate P.
After penetrating through the air intake distribution chamber 16, it is reversed downward from the upstream side of the air intake distribution chamber 16 and opens into the chamber 16.

First to third high-speed intake passages 17 ₁ to 17 ₃ ; 17 ₁ ' to
17 ₃ ′ are the first to third parts whose cross-sectional areas correspond to each other.
The low-speed intake passages 18 ₁ to 18 ₃ are formed to be larger than those of the low-speed intake passages 18 ₁ to 18 ₃ . Further, these high-speed intake passages 17 ₁ to 17 ₃ ; 17 ₁ ′ to 17 ₃ ′ extend linearly along the axis of the crankshaft, and are arranged at their inlet ends a ₁ so that their lengths are approximately equal.
~a ₃ ; The length of entry of a ₁ ′ to _{a 3} ′ into the intake air distribution chamber 16 is adjusted. That is, the first, second, and third high-speed intake passages _{17 1 to 17 3 ;}
a ₃ ; _The plunge lengths _of a ₁ ′ to _{a 3} ′ are increased, and in the illustrated example, the inlet ends a ₁ ,
The plunge length of a ₁ ′ is assumed to be zero.

Furthermore, each low-speed intake passage 18 ₁ to 18 ₃ ; 18 ₁ ' to 1
The sum of the length of 8 ₃ ′ and the length of each high-speed intake path 17 ₁ to 17 ₃ ; 17 _{1 ′} to _{17 3 ′} on the downstream side of the branch ports b ₁ to b ₃ ; 1 and larger than the second length, which is the length of each of the high-speed intake passages 17 ₁ to 17 ₃ ; 17 ₁ ′ to _{17 3} ′. Therefore, the first length is a length that can maximize charging efficiency due to the intake inertia effect when the engine is operated at low speed, and the second length
The length of is such that the filling efficiency can be maximized due to the intake inertia effect during high-speed operation.

As shown in FIG. 1, with the above configuration, the intermediate plate P
Above, high and low speed intake channels are arranged as follows. That is, in the top row, from left to right, the left third low speed intake passage 18 ₃ , the second low speed intake passage 18 ₂ , the right second low speed intake passage 18 ₂ ′, the third low speed intake passage 18 _{3 ′, and the second low speed intake passage 18} 2 .
From the left, the third high-speed intake passage 17 ₃ on the left,
Second high-speed intake passage 17 ₂ , second high-speed intake passage 1 on the right side
7 ₂ ', the third high-speed intake passage 17 ₃ ', the third stage has the left first high-speed intake passage 17 ₁ from the left, the right-hand first high-speed intake passage 17 ₁ ', and the bottom stage has the left first low-speed intake passage. Road 18
₁ , the right first low-speed intake passage 18 ₁ '.

Each of the first to third high-speed intake passages 17 ₁ is provided on the intermediate plate P.
Butterfly type on-off valves 24 ₁ to 24 3 ; 24 _{1 ′} to 24 ₃ ′ for opening and closing the valves _{24 1} to _{17 3} ; Four on-off valves in the upper stage 24 ₃ , 24 ₂ ; 24 ₂ ',
24 ₃ ′ is a high-speed intake passage 17 ₃ , 17 ₂ ; 17 ₂ ′, 1
The two opening/closing valves 21 ₁ , 24 ₁ ' at the lower stage are carried by a long first valve shaft 25 ₁ which horizontally traverses the valve shaft 7 _{3 '} and is supported by the intermediate plate P.
₁ ' horizontally and supported by a short second valve shaft ₂₅₂ supported on the intermediate plate P. As shown in Figure 3,
Both valve shafts 25 ₁ , 25 ₂ are provided with actuating levers 26 ₁ , 26 ₂ at their outer ends, and these actuating levers 26 ₁ , 26 ₂ are connected to each other via an interlocking link 27 and are designed to operate in a specified manner for the engine. The motor is connected to an actuator 28 which is responsive to high rotational conditions. With this configuration, it is possible to centrally arrange a plurality of on-off valves without interfering with any of the intake passages, simplifying the on-off mechanism, and it is possible to form an assembly of the intermediate plate and the on-off valves. The overall assembly is good.

The actuator 28 can be of various types, such as a negative pressure type or an electromagnetic type, but in the case of a negative pressure type, the opening/closing valve is closed by the boost negative pressure of the engine,
It is desirable to configure the valve to open with spring force.

All six low-speed intake passages 18 ₁ ~ 18 ₃ ; 18 ₁ ' ~ 1
8 ₃ ' are arranged around the cylindrical intake distribution chamber 16 along its axial direction, and are connected to each other so as to share a boundary wall.
From the left in the figure, the third low-speed intake passage 18 ₃ on the left, the second low-speed intake passage 18 ₂ , the first low-speed intake passage 18 ₁ , the first low-speed intake passage 18 ₁ ′ on the right, and the second low-speed intake passage 18 ₂ ′ on the right. ,
This is followed by the third low-speed intake passage 18 ₃ '. That is, the intake ports 14 ₃ , 1 closest to the intake distribution chamber 16
Left and right third low-speed intake passages 18 connected to 4 ₃ ' respectively
₃ and 18 ₃ ' are arranged at both ends of the intake air distribution chamber 16.

As shown in FIG. 7, the intake air distribution chamber 16 is formed by a corrugated inner circumferential wall 29 that surrounds the six low-speed intake passages and are connected to each other, and a closed end wall 30 that is connected to one end of the inner circumferential wall 29. defined. Therefore, in this case, there is no need to provide a special box for forming the intake air distribution chamber 16, and the structure is simple.

The other end of the air intake distribution chamber 16 is open as its inlet 16a, and a mounting surface 31 is formed around it. A mounting flange 33 of a throttle valve cylinder 32 is fixed to this mounting surface 31 with bolts 34. Throttle valve tube 32
are provided with primary and secondary intake passages 35 ₁ and 35 ₂ that both communicate with the distribution chamber 16, and the primary intake passage 35
₁ is provided with a primary throttle valve 36 ₁ , and the secondary intake path 35 ₂ is provided with a secondary throttle valve 36 ₂ . An air cleaner 37 is attached to the inlet of the throttle valve cylinder 32.

As shown in FIGS. 1 and 2, the mounting flange 19 of the first block _B1 of the intake manifold M,
19' includes each intake port 14 ₁ to 14 ₃ ; 14 ₁ ' to
Fuel injection nozzle 38 ₁ for injecting fuel into 14 ₃ ′
〜38 ₃ ; 38 ₁ ′ to 38 ₃ ′ are attached.

Next, the operation of this embodiment will be explained. When the engine is operating at low speed, the actuator 28 is in an inactive state and closes the on-off valves 24 ₁ to 24 ₃ ; 24 ₁ ′ to 24 ₃ ′;
The inlet sides of the high-speed intake passages 17 ₁ to 17 ₃ ; 17 ₁ ′ to 17 ₃ ′ are all blocked. Therefore, the air purified by the air cleaner 37 and sucked into the primary intake passage 35 ₁ (and the secondary intake passage 35 ₂ ) during the intake stroke of the engine flows through the primary throttle valve 36 ₁ (and the secondary throttle valve 36 ₂ ) flows into the intake distribution chamber 16 _{with a} flow rate controlled by
₁ ' to ₁₈₃ ', and moves from the branch ports _b1 to _b3 ; _b1 ' to _b3 ' to the downstream side of the high-speed intake passages ₁₇₁ to ₁₇₃ ; ₁₇₁ ' to ₁₇₃ ', and then Port 14 ₁ ~ 14 ₃ ; 1
4 ₁ ′ to 14 ₃ ′ and then sucked into the corresponding cylinders 1 and 1 ′. During this time, the fuel injection nozzles 38 ₁ -
38 ₃ ; Fuel flows from 38 ₁ ′ to 38 ₃ ′ to the intake port 14
₁ to 14 ₃ ; 14 ₁ ' to 14 ₃ ', and these are supplied into each cylinder 1, 1' together with the above air.

Therefore, as mentioned above, the total length of each low-speed intake passage and the high-speed intake passage downstream from its branch port is compared in such a way that the charging efficiency can be maximized due to the intake inertia effect during low-speed operation of the engine. Since the first length is set to a long target, it is possible to satisfy the low speed output performance of the engine, and each low speed intake path 18
₁ to 18 ₃ ; 18 ₁ ' to 18 ₃ ' are arranged in the longitudinal direction of the valley V and are formed to surround the intake air distribution chamber 16, so the intake manifold M as a whole is relatively compact, and both The amount of protrusion from the valley V between the cylinder rows C and C' can be small.

When the engine enters a predetermined high-speed operating state, actuator 2
8 operates to open/close valves 24 ₁ to 24 ₃ ; 24 ₁ ′ to 24
₃ ' is opened, and the high-speed intake passages 17 ₁ to 17 ₃ ; 17 ₁ ' to
17 ₃ ' are all made conductive. Then, during the intake stroke of the engine, the air in the intake air distribution chamber 16 is transferred to the low-speed intake passage 18.
₁ to 18 ₃ ; High-speed intake passages 17 ₁ to 17 ₃ ; 1 having a larger cross-sectional area and lower intake resistance than 18 _{1 '} to 18 ₃ ';
7 ₁ ′ to 17 ₃ ′, and nozzles 38 ₁ to 17 3 ′.
38 ₃ ; Injected fuel from 38 ₁ ′ to 38 ₃ ′ is taken into each cylinder 1, 1′.

As mentioned above, each high-speed intake passage is formed in a straight line, and its length is set to a length that maximizes the charging efficiency due to the intake inertia effect during a predetermined high-speed operation of the engine. Therefore, the intake inertia effect is effectively exhibited and the high-speed output performance of the engine can be fully satisfied.

In such an intake manifold M, the first
The joint surface F ₁ of block B ₁ has both mounting flanges 19,
In the offset direction ε of 19', one end 19e, 1 on the same side of both mounting flanges 19, 19'
9e', so that one end 19e protrudes outward in the crankshaft direction from the joint surface _F1 , and the other end 19e' fits inward in the crankshaft direction from the joint surface _F1 . Therefore, as shown in FIG. 8, when finishing the joint surface F ₁ with the rotary tool T, one end 19 is placed closer to the joint surface F ₁ than the joint surface F 1 .
As long as only one of the mounting flanges 19, which protrudes outward in the direction of the crankshaft (towards the front in the paper), is placed outside the movement path A of the tool T, there will be no interference with the other mounting flange 19'. , the joint surface F ₁ can be processed at once using the tool T.

C. Effects of the Invention As described above, according to the present invention, the first air intake passage is arranged in the valley between a pair of cylinder rows arranged in a V-shape and has a plurality of intake passages connected to the intake ports of each cylinder row. and a common intake distribution chamber connected to the first block at a joint surface substantially perpendicular to the axis of the crankshaft, disposed on the outside of the valley, and connected to the upstream ends of the plurality of intake passages. a second block, the first block is integrally formed with a pair of mounting flanges each connected to both cylinder rows, and a plurality of intake flanges corresponding to one cylinder row of the first block are provided. The passages are arranged to be offset by a certain distance in the axial direction of the crankshaft with respect to the plurality of intake passages corresponding to the other cylinder row, and the mounting flange corresponding to the one cylinder row is arranged such that the mounting flange corresponds to the other cylinder row. In the intake manifold for a V-type internal combustion engine, which is arranged offset in the same way as the plurality of intake passages corresponding to the one cylinder row, the joint surface of the first block is arranged in an offset direction of both the mounting flanges. between the ends of the same side of both mounting flanges, one end protrudes outward in the crankshaft direction beyond the joint surface, and the other end projects inward in the crankshaft direction from the joint surface. When finishing the joint surface, all you have to do is place one of the mounting flanges with one end protruding outward from the joint surface out of the movement path of the tool. The joint surfaces can be machined all at once with the same tool without any hindrance, which can contribute to improving machining efficiency.

Moreover, the above-mentioned joint surface can be placed inward in the crankshaft direction from the above-mentioned one end of one mounting flange without impairing the finish workability thereof, and each mounting flange and its corresponding Offset the intake passage in the same way,
The synergistic effect of minimizing the amount of overhang of the one end of each mounting flange toward the second block side makes it possible to deviate the joint surface inward in the crankshaft direction as much as possible. Therefore, it is possible to contribute to shortening the intake passage in the first block, and even though the second block joined to the joining surface is arranged to protrude outside the valley between both cylinder rows, the intake passage in the first block can be shortened. The amount of overhang of the second block can be minimized, which is advantageous in reducing the size of this type of internal combustion engine in the direction of the crankshaft.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view of the main parts of the entire engine equipped with the intake manifold of the present invention, FIG. 1A is a bottom view of the cylinder head of the engine shown in FIG. 1, and FIG. 2 is a plan view of the main part of FIG. 1, FIG. 3 is a side view of the intake manifold of FIG. 1, and FIGS. 4, 5, and 6 are views of the -
line, - line and - line sectional views, Figure 7 is the second
FIG. 8 is a cross-sectional view taken along the line 1--2, and FIG. 8 is an explanatory view of the finishing process of the joint surface of the first block in the intake manifold of FIG. 1. A...Travel trajectory of the tool, C, C'...Cylinder row, _F1 ...Joint surface, M...Intake manifold,
T...Tool, V...Valley, 16...Intake distribution chamber, 1
7 ₁ to 17 ₃ ; 17 ₁ ′ to 17 ₃ ′...Intake path, 19,
19'...Mounting flange, 19e, 19e'...One end, 20, 20'...Bolt.

Claims (1)

[Claims] 1 A pair of cylinder rows C arranged in a V-shape,
C' is arranged in the valley V between each cylinder row C,
Intake ports 14 ₁ to 14 ₃ of C′; multiple intake passages 17 ₁ to 17 ₃ ; 17 _{1 ′} to 1 connected to the intake ports 14 1 to ₁₄ 3 ;
A first block B ₁ having a diameter of 7 ₃ ' is connected to the first block B ₁ at a joint surface F ₁ substantially perpendicular to the axis of the crankshaft and is disposed on the outside of the valley V. Intake passages 17 ₁ to 17 ₃ ; A second air intake passage having a common intake distribution chamber 16 connected to the upstream ends of 17 ₁ ′ to 17 ₃ ′;
and a block _B2 , and the first block _B1 includes:
A pair of mounting flanges 19, 19' are integrally formed to be connected to both cylinder rows C, C', respectively,
The plurality of intake passages 17 ₁ to 17 ₃ corresponding to one cylinder row C of the first block B ₁ are different from the plurality of intake passages 17 _{1 ′} to 17 corresponding to the other cylinder row C′.
₃ ' in the axial direction of the crankshaft by a certain distance ε, and the one cylinder row C
The mounting flange 19 corresponding to the one cylinder row C is arranged offset from the other mounting flange 19' in the same manner as the plurality of intake passages 17 ₁ to 17 ₃ corresponding to the one cylinder row C. In the intake manifold of an internal combustion engine, the first block B ₁
The joint surface F ₁ of both the mounting flanges 19,
Both mounting flanges 19,
Between one end 19e and 19e' on the same side of 19',
One end portion 19e thereof is arranged so as to protrude outward in the crankshaft direction from the joint surface _F1 , and the other one end portion 19e' is located inward in the crankshaft direction from the joint surface _F1 . An intake manifold for a V-type internal combustion engine.