JP4251393B2 - Intake device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intake device for an internal combustion engine. The present invention also relates to an intake device including a dual port intake manifold in which two intake pipe lines are connected in parallel to one cylinder.
[0002]
[Prior art]
In order to promote weight reduction of an engine, a technique for forming an intake manifold with a synthetic resin material is already known. For example, Japanese Patent Application Laid-Open No. 2001-342918 discloses that a branch pipe is provided along a streamline of an intake flow. A structure in which it is divided and connected to a surge tank is disclosed.
[0003]
In addition, in order to further optimize the intake charging efficiency according to the operating condition of the engine, two intake pipes with different pipe lengths branched from the surge tank are connected in parallel to one cylinder, and negative pressure response There is also known a dual port type intake manifold configured to open and close one intake pipe according to an engine load state by a butterfly valve driven to open and close by an actuator (refer to Japanese Utility Model Publication No. 3-41056). .
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-342918 [Patent Document 2]
Japanese Utility Model Publication No. 3-41056
[Problems to be solved by the invention]
However, since the independent intake pipe corresponding to each cylinder is divided into two along the intake flow line, the one described in the above-mentioned document 1 has a degree of freedom in the configuration of the connection portion between the surge tank and the independent intake pipe. Low. If the dual port intake manifold described in Document 2 is formed of a synthetic resin material for weight reduction, the dual port intake manifold forms two parallel pipe lines for each cylinder, and these communication states Since a butterfly valve or the like for switching between the two has to be provided on one pipe line, the form tends to be complicated, and injection molding with a synthetic resin material using a mold is extremely difficult.
[0006]
The present invention has been devised to solve such problems of the prior art, and its main object is to provide a split intake manifold configured to be injection-molded with a synthetic resin material. An object of the present invention is to provide an intake device for an internal combustion engine.
[0007]
[Means for Solving the Problems]
In order to achieve such an object, in the present invention, a plurality of independent intake pipes (25) individually connected to respective combustion chambers of a plurality of cylinders, and a common surge tank in which the independent intake pipes communicate with each other An intake device for an internal combustion engine including an intake manifold body (26) provided with (24) , wherein the intake manifold body is integrally formed with a connecting portion of a throttle body (22) and an engine-side wall of the surge tank. The inner half (31) formed, and the outer half of the independent intake pipe divided by the surface along the anti-engine side wall of the surge tank and the intake streamline curved with an appropriate curvature with the center of curvature on the engine side (25a) and an outer block which is integrally formed with, the independent pairs cylinder head coupling end of the intake pipe (25c) and the divided surface along the inlet streamline the said separate inner half of the intake pipe (25b) The independent intake pipe constituted by the outer block and the intermediate block is divided into two pipes having different intake pipe lengths at least in part. A path (short pipe line 27, long pipe line 28) is provided in parallel, and a support portion (33) of an on-off valve (29) provided in at least one of the two pipe lines in the intermediate block. ) Are integrally formed .
[0008]
In this way, the intake manifold can be formed by injection molding using a mating mold while further increasing the degree of freedom of the configuration of the connection portion between the independent intake pipe and the surge tank.
[0009]
Furthermore, it can be formed by injection molding using a mold including an independent intake pipe having two pipe lines and an opening / closing valve support portion.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
[0011]
1 and 2 show the engine periphery of an outboard motor constructed according to the present invention. The outboard motor 1 is of a known type that is attached to the stern plate 3 via a stern bracket 2, and the engine 4 is connected to the stern bracket 2 so as to be rotatable around a horizontal tilt shaft 5. It is mounted on a mount case 7 that is substantially integral with the swivel case 6. The substantially entire engine 4 mounted on the mount case 7 is covered with a detachable engine cover 8.
[0012]
The mount case 7 is coupled to the upper end of the extension case 9, and a drive shaft 10 and a crank shaft 11 reaching the screw are connected to each other on the inside.
[0013]
The engine 4 is, for example, an in-line four-cylinder vertical crankshaft engine, and includes a crankcase 12, a cylinder block 13, and a cylinder head 14, and is arranged so that the crankcase 12 side faces forward when sailing. The cylinder head 14 also defines a combustion chamber 19 in which communication with the intake port 15 and the exhaust port 16 is intermittently connected by the intake valve 17 and the exhaust valve 18 (FIG. 2).
[0014]
An intake device 20 is disposed on one side of the crankcase 12, the cylinder block 13, and the cylinder head 14 so as to face each other. The intake device 20 includes an intake silencer chamber 21 and a throttle body 22 that are opposed to the front surface in the traveling direction of the crankcase 12, and an elbow portion 23 and an elbow portion 23 that are connected to the outlet of the throttle body 22. The surge tank portion 24 is formed, and an intake manifold body 26 is formed of an independent intake pipe portion 25 branched from the surge tank portion 24 and individually connected to the intake port 15 of each cylinder. The intake device 20 is coupled to the engine 4 by the surge tank portion 24 being bolted to the side surface of the crankcase 12 and the downstream end portion of the independent intake pipe portion 25 being bolted to the side surface of the cylinder head 14. Has been.
[0015]
In the independent pipes of the independent intake pipes 25 arranged side by side in the cylinder row direction on the side of the cylinder block 13, there is a short part on the side close to the engine in the connection part with the surge tank part 24 located on the intake upstream side. Two pipelines, a pipeline 27 and a long pipeline 28 far from the engine, are provided in parallel. These two pipe lines 27 and 28 are connected to the common pipe line C on the downstream side and extend to the coupling end 25 c with the cylinder head 14. Each short pipe 27 is provided with a butterfly valve 29 that simultaneously operates in the same direction.
[0016]
The intake manifold body 26 is basically formed by combining an independent intake pipe portion 25 and a hollow surge tank portion 24 each having a short pipe line 27 and a long pipe line 28 in parallel at a middle portion thereof into a split mold. As shown in FIG. 3, it is composed of three blocks. That is, as shown in FIG. 4, the intake manifold body 26 includes an inner block 31 that forms an engine side wall 24a of the anti-throttle body coupling portion 30 and the surge tank portion 24, and an appropriate center of curvature on the engine side. An outer block 32 that forms part of the outer peripheral side half portion 25a of the independent intake pipe portion 25 and the wall 24b opposite to the engine side of the surge tank 24, which is divided by a plane P1 along the intake streamline curved with a large curvature; A half portion 25b on the inner peripheral side of the independent intake pipe portion 25, a cylinder head coupling end 25c of the independent intake pipe portion 25, a butterfly valve support portion 33, an upstream side open end 34 of the short pipe line 27, and a surge tank 24 It consists of an intermediate block 35 that forms an elbow portion 23 continuous with the wall 24b on the engine side. The inner block 31 and the intermediate block 35 are divided along a plane P2 that is substantially parallel to the engine-side wall 24a of the surge tank portion 24.
[0017]
These three blocks 31, 32, and 35 are individually formed by injection molding of a synthetic resin material, and then integrally joined by, for example, a vibration welding method. The joint surfaces shown in FIG. As described above, the concave portion 36 and the convex portion 37 are formed, and a predetermined melting allowance 38 is provided in the convex portion 37 so that the convex portion 37 is melted and welded to the concave portion 36.
[0018]
As shown in FIG. 6, the four butterfly valves 29 are provided on a common shaft 40 on which both ends 40a and 40b and the intermediate portion 40c are supported by individually formed shaft holders 39a to 39c. Yes. One end 40b of the shaft 40 is subjected to a resilient force in the radial direction so that it can be smoothly rotated by a resilient piece 41 formed on the corresponding shaft holder 39b. Yes. Further, the shaft holder 39a integrally formed with the outer block 32 corresponds to the other end 40a of the shaft 40 through a minute gap, and the three shaft holders 39c in the middle portion loosen the middle portion 40c of the shaft 40 very loosely. I accept.
[0019]
A diaphragm actuator 42 having a known structure that is driven by negative pressure of the intake pipe is connected to the other end 40a side (the upper side in the crankshaft direction) of the shaft 40 of the butterfly valve 29. The supply of negative pressure to the diaphragm actuator 42 is interrupted by an electromagnetic valve 43 that is turned on / off by a separate control signal, so that the four butterfly valves 29 are driven to open and close simultaneously.
[0020]
Here, the air chamber 44 of the diaphragm actuator 42 is integrally formed with the intermediate block 35, and the number of parts is reduced (FIG. 8).
[0021]
As shown in FIG. 5, a negative pressure chamber 46 is defined at a position adjacent to the surge tank portion 24 in the inner block 31 in cooperation with a recess 45 formed in the vicinity of the butterfly valve 29 in the intermediate block 35. A bulging portion 46a is integrally formed. That is, the negative pressure chamber 46 is a butterfly on the intake downstream side of the butterfly valve 29 on the further inner peripheral side of the short pipe 27 arranged on the inner peripheral side of the independent intake pipe portion 25 curved with the center of curvature on the engine side. It is disposed at a position adjacent to the valve 29. A cylindrical hole 47 whose bottom communicates with the inside of the surge tank 24 is formed in the middle part of the negative pressure chamber 46 in the cylinder row direction. A negative pressure check valve 48 is mounted in the cylindrical hole 47. ing. The negative pressure check valve 48 includes a relatively soft mushroom-shaped valve member 49, and a valve seat 50 that supports the valve member 49 so as to be movable in the axial direction over a predetermined range and to which the valve member 49 abuts. The valve support member 51 includes a valve support member 51, and the valve support member 51 is fitted into the cylindrical hole 47 through a seal member 52 such as an O-ring.
[0022]
In this way, most of the negative pressure chamber 46, most of the surge tank 24, and the cylindrical hole 47 that communicates between them and mounts the negative pressure check valve 48 are intermediate parts constituting the intake manifold body 26. The block 35 is integrally molded. As a result, there is no need to separately provide a connection pipe for guiding the intake pipe negative pressure to the negative pressure chamber 46.
[0023]
When the negative pressure in the intake pipe increases due to the action of the negative pressure check valve 48, the valve member 49 is sucked to the intake pipe side and is separated from the valve seat 50, whereby the negative pressure chamber 46 becomes negative pressure. When the negative pressure in the intake pipe decreases, the valve member 49 is pressed against the valve seat 50 and the negative pressure in the negative pressure chamber 46 is kept high.
[0024]
The negative pressure chamber 46 is connected to the negative pressure chamber 54 of the diaphragm actuator 42 by a rubber tube 53 with an electromagnetic valve 43 interposed therebetween. When the electromagnetic valve 43 is turned on / off, the negative pressure chamber 46 and the diaphragm actuator 42 are connected. Communication with the negative pressure chamber 54 is interrupted. As shown in FIG. 7, the electromagnetic valve 43 is attached to a stay portion 55 integrally formed at a position adjacent to the atmospheric chamber 44 of the diaphragm actuator 42 on the side surface of the intermediate block 35 with a screw means. In combination with the fact that 46 is disposed close to the butterfly valve support 33, the rubber tube 53 that connects the negative pressure chamber 46, the electromagnetic valve 43, and the negative pressure chamber 54 of the diaphragm actuator 42 is further shortened. Has been realized.
[0025]
With the above configuration, in the state where the diaphragm 57 is pushed out to the atmosphere chamber 44 side by the extension force of the compression coil spring 56 contracted in the negative pressure chamber 54 of the diaphragm actuator 42, the butterfly valve 29 opens and immediately before the butterfly valve 29. A state in which the short pipe line 27 extending from the open end 34 located at the center to the cylinder head coupling end 25c through the common pipe C and the intake upstream end of the long pipe line 28 is communicated (high speed / high load operation region) Become. When the diaphragm 57 is drawn toward the negative pressure chamber 54 by introducing a negative pressure into the negative pressure chamber 54 of the diaphragm actuator 42, the butterfly valve 29 is closed (the state indicated by a two-dot chain line in FIG. 4), Only the long pipe 28 where the opening end 28a is located upstream of the opening end 34 of the short pipe 27 communicates (low speed / low load operation region). In this way, the cross-sectional area of the intake pipe and the pipe length can be switched in two stages according to the operating state of the engine 4.
[0026]
As shown in FIG. 4, the downstream edge of the pipe wall 58 separating the most upstream portion of the long pipe passage 28 from the short pipe passage 27 and the open end 34 of the short pipe passage 27 in the surge tank 24 It is placed on the same plane D. This plane D is orthogonal to the parting surface of the mold together with the axis of the cylinder head coupling end 25c of the independent intake pipe portion 25, so that the middle block 35 is not obstructed. . Note that the axis of the recess 45 forming the negative pressure chamber 46 and the axis of the cylindrical hole 47 in which the negative pressure check valve 48 is mounted are also taken into account in consideration of die cutting of the intermediate block 35. It is orthogonal to.
[0027]
The direction of the central axis A of the atmospheric chamber 44 of the diaphragm actuator 42 is inclined with respect to the die-cutting direction of the intermediate block 35, that is, the direction parallel to the plane D (see FIG. 8). It is molded using another slide mold 61. If the opening surface 62 of the atmospheric chamber 44 is directed right above in FIG. 8 and the central axis A is parallel to the plane D, another slide mold 61 can be eliminated.
[0028]
【The invention's effect】
As described above in detail, according to the first aspect of the present invention, the surge tank is formed by integrally molding at least the connecting portion of the throttle body and the wall on the engine side, and at least the anti-engine. Since the intake manifold body is formed by dividing a part of the side wall and the end portion on the intake upstream side of the independent intake pipe into a second portion (central block) formed by integral molding, The intake manifold can be formed by injection molding using a mating mold after further increasing the degree of freedom of the configuration of the connecting portion of the pipe to the surge tank. According to the second aspect of the present invention, the independent intake pipe and the butterfly valve support portion can be formed by injection molding using a mold. Therefore, according to the present invention, it is possible to achieve a great effect in increasing the productivity of this type of variable pipe length type intake device that tends to be complicated.
[Brief description of the drawings]
FIG. 1 is a side view of an essential part of an outboard motor to which the present invention is applied. FIG. 2 is a top view of the outboard motor to which the present invention is applied. FIG. 3 is an exploded perspective view of an intake manifold body according to the present invention. 4 is a horizontal cross-sectional view of an intake manifold body according to the present invention. FIG. 5 is a horizontal cross-sectional view of the main part of the intake manifold body according to the present invention. Fig. 8 is a top plan view of the main part of the intake manifold body according to the present invention. Fig. 8 is a top plan view of the main part of the diaphragm actuator forming part of the intake manifold body according to the present invention.
19 Combustion chamber 20 Intake device 23 Elbow part 24 Surge tank 24a Engine side wall 24b Anti-engine side wall 25a Outer side half part 25b Inner side half part 26 Intake manifold body 27 Short pipe line 28 Long pipe line 29 Butterfly valve 30 Anti-throttle body coupling portion 31 Inner block 32 Outer block 33 Butterfly valve support portion 34 Short pipe opening end 35 Central block

Claims (2)

An intake system for an internal combustion engine including an intake manifold body including a plurality of independent intake pipes individually connected to respective combustion chambers of a plurality of cylinders, and a common surge tank communicating with each of the independent intake pipes. ,
The intake manifold body includes an inner block formed integrally with a throttle body connecting portion and an engine side wall of the surge tank, and an appropriate curvature having a center of curvature on the anti-engine side wall and the engine side of the surge tank. An outer block formed integrally with the outer half of the independent intake pipe divided by a surface along the curved intake flow line, and a divided surface of the independent intake pipe with a cylinder head coupling end and a surface along the intake flow line. In addition, the inner half of the independent intake pipe is divided into three parts by an integrally formed intermediate block,
The independent intake pipe constituted by the outer block and the intermediate block is provided in parallel with two pipe lines having different intake pipe lengths in at least a part thereof,
An intake device for an internal combustion engine, wherein a support portion for an on-off valve provided in at least one of the two pipes is formed integrally with the intermediate block . The intake device for an internal combustion engine according to claim 1, wherein the inner block, the outer block, and the intermediate block are injection molded products of a synthetic resin material, and are integrally coupled by a vibration welding method.

Images