JPH0972256A - Intake device in multicylinder internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve durability and assembling performance without increasing flowing resistance of intake gas in the case of composing an intake manifold, which connects an intake port for respective cylinders in an internal combustion engine to a throttle body or a carburetor, of synthetic resin. SOLUTION: A large-diameter socket hole 15 and a large-diameter socket hole 19 are provided in an outlet of a throttle body 6 or a carburetor, and in respective intake port inlets of a cylinder head respectively, while the end 12a of a collecting pipe 12 of an intake manifold on which an O-ring 17 for sealing is coveringly fitted is detachably inserted in the socket hole of the throttle body or the carburetor and the ends 13a of respective intake pipes 13 of the intake manifold on which an O-ring 21 for sealing is coveringly fitted are detachably inserted in the socket hole of respective intake ports.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for a multi-cylinder internal combustion engine, in which intake air from one air cleaner is introduced into each cylinder via an intake manifold.

[0002]

2. Description of the Related Art Conventionally, the intake manifold used in this type of intake device has generally been made of cast iron or aluminum alloy, but in recent internal combustion engines, In order to reduce the cost and the weight, the intake manifold is made of synthetic resin.

In a conventional intake manifold made of synthetic resin, a throttle body or a carburetor is formed by fastening a collecting pipe with a plurality of bolts at a flange portion integrally provided on the outer circumference of the tip of the collecting pipe. On the other hand, each intake pipe branched from the collecting pipe while being connected to each other is provided with a flange portion integrally provided on each outer periphery of the tip end of the intake pipe by a plurality of bolts to the side surface of the cylinder head in the internal combustion engine. It is configured to be connected to each of the intake ports to each cylinder by fastening.

However, this conventional synthetic resin intake manifold is connected to the throttle body or the carburetor and the cylinder head by fastening a plurality of bolts to a flange portion integrally provided on the intake manifold side. Since it is configured as described above, it is unavoidable that creep deformation peculiar to synthetic resin occurs due to bolt fastening in each of the flange portions, and the airtightness at each joint portion is reduced early. Therefore, there was a problem that durability was low.

Moreover, in the conventional intake manifold made of synthetic resin, the connection to the throttle body or the carburetor and the cylinder head is made by fastening a plurality of bolts to the flange portion integrally provided on the intake manifold side. Since it is configured as described above, not only the number of steps required for assembling and disassembling increases, but also the number of parts increases, and
There is also a problem that it causes an increase in size and an increase in weight.

An object of the present invention is to eliminate the above-mentioned problems in the case where the intake manifold of the intake device is made of synthetic resin without causing an increase in intake resistance.

[0007]

In order to achieve this technical object, the present invention provides "a downstream side of a throttle body or a carburetor attached to an internal combustion engine, and an intake port to each cylinder of a cylinder head in the internal combustion engine. The intake device is formed by connecting an intake manifold made of synthetic resin with a collecting pipe connected to the throttle body or the carburetor and an intake pipe branching from the collecting pipe toward the intake ports. At the downstream side outlet of the throttle body or the carburetor, a socket hole having a diameter larger than the outlet is provided, and at the inlet of each intake port in the cylinder head, a socket hole having a diameter larger than the intake port is provided. , A distal end portion of the collecting pipe in the intake manifold is fitted with a sealing O-ring, and a bore passage in the throttle body or the carburetor is inserted. The socket downhole, the leading end of the intake pipes in the intake manifold, O seal thereto
The rings are fitted and inserted into the socket holes of the intake ports in a detachable manner. ".

[0008]

As described above, according to this structure, the tip end of the collecting pipe in the synthetic resin intake manifold is attached to the internal combustion engine after the O-ring is fitted to the tip end portion of the throttle body or the downstream side outlet of the carburetor. The intake manifold is inserted into the socket holes while the end portions of the intake pipes in the intake manifold are inserted into the socket holes of the intake ports in the cylinder head of the internal combustion engine after the O-rings are fitted on the intake pipes. It is possible to reliably connect the collecting pipe to the downstream outlet of the throttle body or the carburetor, and connect each intake pipe to each intake port of the cylinder head while maintaining high airtightness.

Further, since the socket hole at the downstream side outlet of the throttle body or the carburetor and the socket hole at each intake port of the cylinder head are formed to have a diameter larger than that of each outlet and intake port, the intake manifold. The inner diameter of the tip of the collecting pipe in can be made close to the inner diameter of the throttle body or the downstream side outlet of the carburetor, and the inner diameter of the tip of each intake pipe in the intake manifold is set to the inner diameter of each intake port in the cylinder head. Since they can be brought close to each other, it is possible to reliably prevent the flow resistance of the intake air from increasing at the connection portion of the collecting pipe to the throttle body or the carburetor side and the connection portion of each intake pipe to the intake port.

Therefore, according to the present invention, when the entire intake manifold consisting of the collecting pipe and the plurality of intake pipes branched from the collecting pipe is made of synthetic resin, the flow resistance of the intake air is increased. It is possible to drastically reduce the number of steps required to connect the collecting pipe to the throttle body or carburetor, and to connect each intake pipe to the cylinder head, without increasing the number of parts and to increase the size. And the increase in weight can be reliably avoided, and further, the airtightness at each connection part can be prevented from being lowered by the creep deformation peculiar to the synthetic resin, and the durability can be greatly improved. .

When the intake manifold is molded of synthetic resin, the intake manifold is distorted. In this intake manifold, the tip end of each intake pipe has the above-mentioned distortion in the intake manifold. Must be inserted into the socket hole in each intake port of the cylinder head while correcting the resistance against its elasticity, and at the time of this insertion, the sealing O-ring fitted in each intake pipe is damaged. Will be
Moreover, the elastic restoring force acts on the sealing O-ring, so that the sealing O-ring is likely to have an early fatigue.

In contrast to this, according to the present invention, as described in "Claim 2", a diameter smaller than the socket hole and larger than the intake port is provided in the depth of the socket hole in each intake port of the cylinder head. While providing the guide hole, it is proposed to provide a guide tube portion that is detachably fitted in the guide hole at the tip of each intake tube of the intake manifold. As a result, the tip of each intake pipe of the intake manifold is
When the intake manifold is displaced from the socket hole in each intake port of the cylinder head due to distortion or the like generated when molding the intake manifold, the guide pipe portion at the tip of each intake pipe is While correcting the distortion in the pipe against its elasticity, by inserting into the guide hole in each intake port of the cylinder head, it is possible to support the elastic restoring force when the distortion of the intake manifold is corrected. Inserting the tip of each intake pipe into the socket hole with the O-ring for sealing fitted thereto can be done smoothly without damaging the O-ring for sealing, and the O-ring for sealing described above. Since the elastic restoring force can be prevented from acting, the workability of assembly and the durability of the sealing O-ring can be improved.

Further, as in claim 3, by providing ribs integrally connecting between the intake pipes in the intake manifold, the rigidity of the synthetic resin intake manifold is improved. By utilizing the gap between the intake manifold and the intake manifold, it is possible to improve the intake manifold without increasing the size thereof, and it is possible to securely support the intake manifold with respect to the internal combustion engine.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 7 show a first embodiment.
The first embodiment is applied to a multi-cylinder internal combustion engine 1 in which an axis line 1a of a cylinder bore is vertical when viewed from the direction of the crankshaft. The internal combustion engine 1 is fastened to a cylinder block 2 and an upper surface thereof. And an intake port 4 for each of a plurality of cylinders is formed inside the cylinder head 3 so as to open to a side surface of the cylinder head 3. Is provided with a fuel injection valve 5.

Reference numeral 6 indicates a throttle body having a built-in throttle valve 7. The throttle body 6 is provided with a bolt 9 on the side surface of the cylinder head 3 with the axis 8a of the bore passage 8 being substantially vertical. It is detachably attached to the fastened bracket 10, and an intake passage from an air cleaner (not shown) is connected to the upstream side of the throttle body 6.

Reference numeral 11 denotes an intake manifold, which is provided with one collecting pipe 12 and a plurality of intake pipes 13 branching from the collecting pipe 12 toward each cylinder. It is formed by injection molding of (for example, 6 nylon mixed with about 30 wt% of glass fiber). At the outlet of the bore passage 8 of the throttle body 6, a guide hole 14 having an inner diameter D2 larger than the inner diameter D1 of the bore passage 8 and a socket hole 15 having an inner diameter D3 larger than the inner diameter D2 of the guide hole 14 are formed. While forming the end portion 12a of the collecting pipe 12 in the intake manifold 11 into a guide pipe portion 16 integrally provided therein so as to be closely fitted in the guide hole 14, an O-ring 17 for sealing is formed. After fitting, the O-ring 17 is inserted into the socket hole 15 of the throttle body 6 so as to be in close contact with the inner surface of the socket hole 15.

At the inlet of each intake port 4 of the cylinder head 3, a guide hole 18 having an inner diameter d2 larger than the inner diameter d1 of the intake port 4 and an inner diameter d3 larger than the inner diameter d2 of the guide hole 18 are provided. While forming the socket hole 19, the tip end portion 13a of each intake pipe 13 in the intake manifold 11 is provided with the guide hole 18
Guide tube portion 20 integrally provided so as to be closely fitted inside
After the O-ring 21 for sealing is fitted on, the O-ring 21 is inserted into the socket hole 19 of each intake port 4 of the cylinder head 3 so as to be in close contact with the inner surface of the socket hole 19.

As a result, the collecting pipe 12 in the intake manifold 11 is connected to the bore passage 8 in the throttle body 5.
In addition, each intake pipe 13 can be reliably connected to each intake port 4 in the cylinder head 3 while maintaining high airtightness. In this case, since the inner diameters of the guide hole 14 and the socket hole 15 at the outlet of the bore passage 8 of the throttle body 6 are made larger than the inner diameter of the bore passage 8, the guide pipe portion 16 and the tip portion 12a fitted therein are fitted. Since the inner diameter of can be increased so as to approach the inner diameter of the bore passage 8, the flow resistance of the intake air in this portion can be reduced.

Further, by making the inner diameters of the guide hole 18 and the socket hole 19 at the inlet of each intake port 4 of the cylinder head 3 larger than the inner diameter of the intake port 4, the guide pipe portion 20 and the tip fitted to these are introduced. Since the inner diameter of the portion 13a can be increased so as to approach the inner diameter of the intake port 4, the flow resistance of the intake air in this portion can be reduced.

On the other hand, as shown in FIG. 7, the tip portion 13a of each intake pipe 13 in the intake manifold 11 corrects the distortion generated when the intake manifold 11 is molded with synthetic resin against its elasticity. Meanwhile, the cylinder head 3 is inserted into the socket holes 19 of the intake ports 4 all at once.
By inserting the guide tube portion 20 in a into the guide hole 18 in each intake port 4 of the cylinder head 3, it is possible to support the elastic restoring force when the distortion of the intake manifold 11 is corrected. Inserting the tip end portion 13a of the intake pipe 13 into the socket hole 19 with the O-ring 20 for sealing fitted to the end portion 13a makes
The ring 20 can be made smooth without being damaged, and the elastic restoring force described above can be prevented from acting on the sealing O-ring 21.

In the first embodiment, the raised portion 11 is provided below the collecting pipe 12 of the intake manifold 11.
a is integrally provided, and the raised portion 11a is brought into contact with the upper surface of the bracket 10 for attaching the throttle body 6 to the cylinder head 3, whereby the collecting pipe 1
The second end 12a of the throttle body 2 is configured to be prevented from coming out of the socket hole 15 in the throttle body 6.

8 to 13 show a second embodiment. The second embodiment is applied to a slant type multi-cylinder internal combustion engine 1'where the axis 1a 'of the cylinder bore is inclined by an appropriate angle .theta. With respect to the horizontal plane when viewed from the direction of the crankshaft. 1'is a cylinder block 2 ',
A cylinder head 3'fastened to the upper surface of the cylinder head 3 ', and an intake port 4'to each of the plurality of cylinders is provided inside the cylinder head 3'in the upward direction on the left and right side surfaces of the cylinder head 3'. It is formed so as to open on the side surface.

Reference numeral 6'indicates a throttle body having a built-in throttle valve 7 '. This throttle body 6 is
The bore passage 8'is attached to the cylinder block 2'removably via a bracket 10 'with the axis 8a' of the bore passage 8'in a substantially horizontal direction. The upstream side of the throttle body 6'is An intake passage from an air cleaner (not shown) is connected.

Reference numeral 11 'indicates an intake manifold,
This intake manifold 11 'has one collecting pipe 12'.
And a plurality of intake pipes 13 'branching from the collecting pipe 12' toward each cylinder, the synthetic resin (for example, 6
Nylon mixed with about 20 wt% glass fiber)
Is formed by blow molding. At the outlet of the bore passage 8'of the throttle body 6 ', a guide hole 14' having an inner diameter D2 'larger than the inner diameter D1' of the bore passage 8 ', and an inner diameter D of this guide hole 14' are provided.
While forming a socket hole 15 'having an inner diameter D3' larger than 2 ', the tip portion 12a' of the collecting pipe 12 'in the intake manifold 11' is sealed in an annular groove provided on the outer periphery thereof for sealing O. In the socket hole 15 'of the throttle body 6'with the ring 17' fitted and the guide tube portion 16 'closely fitted in the guide hole 14' provided integrally with the tip portion 12a '. And the above O
The ring 17 'is inserted so that it closely contacts the inner surface of the socket hole 15'.

At the inlet of each intake port 4'of the cylinder head 3 ', a guide hole 18' having an inner diameter d2 'larger than the inner diameter d1' of the intake port 4 ', and an inner diameter of this guide hole 18'. While forming a socket hole 19 'having an inner diameter d3' larger than d2 ', the tip end portion 13a' of each intake pipe 13 'in the intake manifold 11' is formed.
And an O-ring 2 for sealing in an annular groove provided on the outer periphery thereof.
In each intake port 4'of the cylinder head 3'with the guide tube portion 20 'fitted tightly fitted in the guide hole 18' at the tip portion 13a ', the guide port portion 1'is fitted. The O-ring 21 'is inserted into the socket hole 19' so as to be in close contact with the inner surface of the socket hole 19 '.

As a result, the collecting pipe 12 'in the intake manifold 11' is provided in the bore passage 8'in the throttle body 5 ', and the intake pipes 13' are provided in the intake ports 4'in the cylinder head 3 ', respectively, so that the airtightness is high. It is possible to connect securely while holding the. Also in this case, the inner diameters of the guide hole 14 'and the socket hole 15' at the outlet of the bore passage 8'of the throttle body 6'are
By making the inner diameter of the bore passage 8'larger, the inner diameters of the guide tube portion 16 'and the tip portion 12a' fitted therein can be made larger so as to approach the inner diameter of the bore passage 8 '. The flow resistance of the intake air in the part can be reduced.

Further, since the inner diameters of the guide hole 18 'and the socket hole 19' at the inlet of each intake port 4'of the cylinder head 3'are made larger than the inner diameter of the intake port 4 ', a guide fitted therein. Since the inner diameters of the pipe portion 20 'and the tip portion 13a' can be increased so as to approach the inner diameter of the intake port 4 ', the flow resistance of intake air in this portion can be reduced.

Also in this second embodiment, the tip portions 13 of the intake pipes 13 'in the intake manifold 11' are also provided.
As in the case of the first embodiment, a'is corrected by correcting the distortion generated when the intake manifold 11 'is molded with a synthetic resin against its elasticity, and each intake air in the cylinder head 3'. The guide pipe portions 20 'at the tip end portions 13a' of the intake pipes 13 'are inserted into the socket holes 19' of the port 4'at the same time as the guide holes at the intake ports 4'of the cylinder head 3 '. Since the elastic restoring force when the distortion of the intake manifold 11 'is corrected can be supported by inserting it into the 18', the tip end portions 13a 'of the intake pipes 13' will be attached to the O for sealing. Inserting the ring 21 'into the socket hole 19' with the ring 21 'fitted therein can be performed smoothly without damaging the sealing O-ring 21', and the sealing O-ring 21 'can be smoothly performed.
It is possible to prevent the elastic restoring force described above from acting.

Furthermore, in this second embodiment,
Ribs 11a 'connecting the intake pipes 13' in the intake manifold 11 'are provided at the same time when the intake manifold 11' is blow-molded with a synthetic resin. Is configured to be fastened with a bolt 25 to a bracket 24 for supporting the ignition coil 23 with respect to the cylinder head 3 ', whereby the rigidity of the synthetic resin intake manifold 11' can be increased. At the same time, the intake manifold 11 'can be attached to the cylinder head 3' so as not to come off.

In both of the embodiments described above, socket holes 14 and 14 'are provided at the outlets of the bore passages 8 and 8'in the throttle bodies 6 and 6', and the socket holes 14 and 14 'are made of synthetic resin. The case where the collecting pipes 12 and 12 'of the intake manifolds 11 and 11' are inserted and connected is shown. However, in the case of an internal combustion engine using a carburetor instead of the throttle body, it is provided at the outlet of the bore passage in the carburetor. A socket hole may be provided, and a collecting pipe of a synthetic resin intake manifold may be inserted and connected to the socket hole. Further, a surge tank or a short passage may be provided on the downstream side of the throttle body, or vaporization may be performed. When a short passage is provided on the downstream side of the container, a socket hole is provided at the outlet of these surge tanks or short passages as described above, and Is the may be configured to connect Plug collecting pipe of synthetic resin intake manifold.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a first embodiment of the present invention.

FIG. 2 is a partially cutaway plan view of FIG.

FIG. 3 is an enlarged cross-sectional view showing a connecting portion between a collecting pipe of an intake manifold and a throttle body in FIG.

FIG. 4 is a diagram showing a disassembled state of FIG. 3;

5 is an enlarged cross-sectional view showing a connecting portion between each intake pipe of the intake manifold and the cylinder head in FIG.

FIG. 6 is a diagram showing a disassembled state of FIG. 5;

FIG. 7 is a diagram showing a state where each intake pipe of the intake manifold in FIG. 2 is connected to a cylinder head.

FIG. 8 is a vertical sectional front view showing a second embodiment of the present invention.

9 is a partially cutaway plan view of FIG. 8. FIG.

10 is an enlarged cross-sectional view showing a connecting portion between a collecting pipe of an intake manifold and a throttle body in FIG.

FIG. 11 is a diagram showing a disassembled state of FIG. 10;

FIG. 12 is an enlarged cross-sectional view showing a connecting portion between each intake pipe of the intake manifold and the cylinder head in FIG.

FIG. 13 is a diagram showing a disassembled state of FIG. 12;

[Explanation of symbols]

1,1 'Internal combustion engine 3,3' Cylinder head 4,4 'Intake port 6,6' Throttle body 7,7 'Throttle valve 8,8' Bore passage 11,11 'Intake manifold 12,12' Collecting pipe 12a, 12a 'Tip of collecting pipe 13,13' Intake pipe 13a, 13a 'Tip of intake pipe 14,14' Guide hole for throttle body 15,15 'Socket hole for throttle body 16,16' Guide pipe 17,17 'O-ring 18,18' Inlet port guide hole 19,19 'Inlet port socket hole 20,20' Guide tube portion 21,21 'O-ring

Claims (3)

[Claims] 1. A collecting pipe connected to the throttle body or the carburetor between a downstream side of the throttle body or the carburetor attached to the internal combustion engine and an intake port to each cylinder of a cylinder head in the internal combustion engine. In an intake device connected by an intake manifold made of synthetic resin having an intake pipe branching from this collecting pipe toward each of the intake ports, in the downstream side outlet of the throttle body or the carburetor, from the outlet And a socket hole having a larger diameter than the intake port is provided at the inlet of each intake port in the cylinder head, while the tip end of the collecting pipe in the intake manifold is provided with a sealing O Each intake pipe in the intake manifold is fitted into a socket hole of a bore passage of the throttle body or the carburetor by fitting a ring. The tip intake system in a multi-cylinder internal combustion engine, characterized in that the freely inserted removably into each thereto fitted on a sealing O-ring and the socket hole in the respective intake port. 2. In the "claim 1", a guide hole having a diameter smaller than that of the socket hole and larger than that of the intake port is provided at the back of the socket hole in each intake port of the cylinder head, while the guide hole of the intake manifold is provided. An intake system for a multi-cylinder internal combustion engine, characterized in that a guide tube portion that is detachably inserted into the guide hole is provided at a tip portion of each intake tube. 3. The intake system for a multi-cylinder internal combustion engine according to claim 1, wherein ribs connecting the intake pipes of the intake manifold are integrally provided.