JP2003083075A - Variable intake device for multi-cylinder engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable molding of a valve hole even when dividing an intake distribution box on a face crossing a wall face of a bulkhead having the valve hole orthogonally in a variable intake device for an engine. SOLUTION: In this variable intake device for the multi-cylinder engine constituted in such a way that the inside of the intake distribution box 30 is divided into a first distribution chamber 37L and a second distribution chamber 37R by the bulkhead 35, a first intake branch pipe 38L and a second intake branch pipe 38R opened in these distribution chambers 37L, 37R, respectively, are continuously provided in the intake distribution box 30, and the valve hole 40 communicating the first and second distribution chambers 37L and 37R mutually and a butterfly type opening and closing valve 41 opening and closing the valve hole 40 are provided on the bulkhead 35, the valve hole 40 is composed of a deep cut-out part 40a molded on a divided face on one side of the bulkhead 35 divided by the face crossing the wall face of the bulkhead 35 orthogonally and provided with taper θ widened toward an opening face and a shallow cut- out part 40b molded on a divided face on the other side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake distribution box having an intake inlet communicating with an intake passage of a throttle body, and a first partition wall and a second distribution partition which communicate with the intake inlet by a partition wall in the intake distribution box. First and second intake branch pipes, which are divided into chambers and open to the first and second distribution chambers and respectively connect to the intake ports of the first and second banks of the engine, are connected to the intake distribution box. The partition wall is provided with a valve hole that communicates between the first and second distribution chambers, and a butterfly-type on-off valve that opens and closes the valve hole, and the intake valve characteristic is opened and closed according to the operating state of the engine. By changing
The present invention relates to a variable intake system for a multi-cylinder engine that can maintain high output performance in a wide operating range from low speed to high speed of the engine.

[0002]

2. Description of the Related Art A variable intake system for such a multi-cylinder engine is already known, as disclosed in, for example, Japanese Patent Laid-Open No. 9-88746.

[0003]

By the way, in the air intake device disclosed in the above publication, the air intake distribution box is divided into a plurality of parts by a dividing surface parallel to the wall surface of the partition wall having the valve holes, and the partition wall is made independent. The valve hole is formed at the same time when molding the partition wall or injection molding.

However, depending on the structure of the air intake device, it may be necessary to divide the air intake distribution box by a surface orthogonal to the wall surface of the partition wall having the valve holes in the molding thereof. It becomes difficult to form the valve hole.

The present invention has been made in view of the above circumstances. Even when the intake distribution box is divided by the plane orthogonal to the wall surface of the partition wall having the valve holes, the valve holes can be easily molded. It is an object of the present invention to provide a variable intake system for a multi-cylinder engine, which is obtained.

[0006]

In order to achieve the above object, the present invention provides an intake distribution box with an intake inlet connected to an intake passage of a throttle body, and the inside of the intake distribution box is formed by a partition wall to form the intake inlet. First and second intake branch pipes that are divided into first and second distribution chambers that communicate with each other and that open into the first and second distribution chambers and that respectively communicate with the intake ports of the first and second banks of the engine. Is provided in an intake distribution box, and the partition wall is provided with a valve hole that communicates between the first and second distribution chambers and a butterfly-type on-off valve that opens and closes the valve hole. In one side of the partition wall, which is divided by a surface orthogonal to the wall surface of the partition wall, and is formed on both side edges facing each other so that the distance between the both side edges widens toward the opening surface. U-shaped deep notch and the other Is molded on the dividing plane, the first characterized by being configured the valve hole at a shallow notches of the U-shaped to match the deep notch the opening surface.

According to this feature, even when the intake device is divided along the plane orthogonal to the wall surface of the partition wall having the valve hole, the portion having the deep notch and the portion having the shallow notch are cast or injection-molded. At the time of molding such as, for example, the notch is formed at the same time, and their opening surfaces are aligned with each other, so that the valve hole can be easily configured. In particular, since the deep notch is tapered on both side edges facing each other so that the distance between the both sides increases toward the opening surface, it is easy to release from the notch at the time of molding. After molding, it is possible to obtain a precise valve hole without scratches on the inner surface without performing a troublesome valve hole finishing process, and it is possible to improve productivity. The partition wall portion having the deep notch and the partition wall portion having the shallow notch correspond to the partition wall other half main body 55 and the partition wall piece 56 in an embodiment of the present invention described later, respectively.

In addition to the first characteristic, the present invention has a second characteristic that the partition wall portion having the deep notch and the shallow notch is made by casting.

According to the second feature, thermal distortion of the partition wall portion having the deep notch and the shallow notch, respectively, and therefore the deformation of the valve hole is surely prevented, and the proper opening / closing function of the on-off valve is always ensured. can do.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on an embodiment of the present invention shown in the accompanying drawings.

FIG. 1 is an overall side view of the outboard motor, FIG. 2 is a longitudinal sectional view of an essential part of FIG. 1, FIG. 3 is a sectional view taken along line 3-3 of FIG. 2, and FIG. 4 is a sectional view taken along line 4-4 of FIG. 5 and 5 are sectional views taken along line 5-5 of FIG. 4, FIG. 6 is sectional view taken along line 6-6 of FIG. 5, FIG. 7 is sectional view taken along line 7-7 of FIG. 5, and FIG. 8 is intake air corresponding to FIG. FIG. 9 is an exploded view of a main part of the manifold, FIG. 9 is a sectional view taken along line 9-9 of FIG. 8, and FIG.
11 is an enlarged view of FIG. 11, FIG. 11 is a view taken along arrow 11 of FIG. 8, and FIG.
12 is a sectional view taken along line 12-12, FIG. 13 is a sectional view taken along line 13-13 of FIG. 11, and FIG. 14 is a sectional view showing a method for casting a lid.

In the following description, front, rear, left and right are
The hull H to which the outboard motor O is attached is used as a reference.

1 to 3, an outboard motor O attached to a rear end of a hull H is composed of a mount case 1, an extension case 2 connected to a lower end surface of the mount case 1, and a lower portion of the extension case 2. It is equipped with a gear case 3 that is connected to the end face, and a mount case 1
A V-type 6-cylinder water-cooled 4-stroke engine E is mounted on the upper end surface of the with the crankshaft 4 placed vertically.

An annular under cover 14 is fixed to the mount case 1 via a stay 13. The under cover 14 covers the periphery of the section from the lower portion of the engine E to the upper portion of the extension case 2, and the engine hood 12 that covers the engine E from above is provided on the upper end thereof.
Is detachably attached. This engine hood 12
An engine room 15 that houses the engine E is defined by the under cover 14.

The engine E includes a crankcase 5 supporting a vertically mounted crankshaft 4, a pair of left and right banks 6L extending in a V shape from the crankcase 5 toward the rear.
6R, and the lower surface of the crankcase 25 is bolted to the upper mounting surface of the mount case 1.

As shown in FIGS. 5 and 6, each bank 6
L and 6R are a plurality of vertically arranged lines (three in the illustrated example)
Cylinder bores 7L and 7R are provided. Further, the left and right banks 6L and 6R are bolted to the rear end surface of the crankcase 25, and the cylinder block 7 having the left and right cylinder bores 7L and 7R, and the left and right banks of the cylinder block 7 where the cylinder bores 7L and 7R are opened, respectively. A pair of cylinder heads 9L, 9R bolted to the rear end surface,
The cylinder heads 9L and 9R are composed of a pair of head covers 10L and 10R coupled to the rear end surfaces of the cylinder heads 9L and 9R so as to close the valve operating chambers formed therein.

2 to 4, the engine hood 12 is shown.
An air intake 16 is provided at the upper rear part of the engine, and the lower end communicates with the air intake 16 and the lower end is in the engine room 15.
A flat ventilation duct 17 that opens to the bottom of the engine hood 12 is arranged along the inner surface of the rear wall of the engine hood 12. The air taken into the engine room 15 by the ventilation duct 17 is taken into the left and right banks 6L and 6R through the intake silencer 18 and the intake manifold Mi.

The intake silencer 18 is mounted on the upper surface of the engine E, has a box shape, and has a pair of left and right inlets 20, 20, and an outlet 21 arranged between these inlets 20, 20. The upstream end of the intake passage 22a of the throttle body 22 is connected to the outlet 21. A throttle valve 23 that is interlocked with an accelerator lever (not shown) provided on the hull H is pivotally supported by the intake passage 22a.

5 to 7, the intake manifold Mi which is connected to the downstream end of the intake passage 22a of the throttle body 22 is arranged facing the valley 24 between the left and right banks 6L and 6R. Further, in the valley 24, a plurality of left intake pipes 26L connected to the plurality of intake ports 25L of the cylinder head 9L of the left bank 6L and a plurality of intake ports 25R formed in the cylinder head 9R of the right bank 6R are connected. The plurality of right intake pipes 26R are arranged so that their upstream ends face rearward. At the upstream ends of the plurality of left intake pipes 26L, the left connecting flange 2 for connecting these to each other is provided.
7L is integrally formed, and a right connecting flange 27R is formed integrally at the upstream ends of the plurality of right intake pipes 26R. Left and right banks 6L, 6R intake pipe 2
Electromagnetic fuel injection valves 28L, 2 that inject fuel into the corresponding 6L, 26R toward the intake valves of the corresponding banks 6L, 6R
8R is attached.

The intake manifold Mi is provided with an intake distribution box 30 which is long in the vertical direction and flat in the front-rear direction, and is arranged so as to straddle both rear surfaces of the left and right banks 6L, 6R. At the upper part of the front wall of the intake distribution box 30, a connecting flange 32 having an intake inlet 31 at the center is formed, and a connecting flange 33 formed at the downstream end of the throttle body 22 is joined thereto.

A partition wall 35 extending in the vertical direction is provided in the intake distribution box 30, whereby the interior of the intake distribution box 30 is divided into a left distribution chamber 37L and a right distribution chamber 37R which communicate with the intake inlet 31, respectively. . The partition wall 35 is connected to a guide wall 36 that divides the air flowing into the intake inlet 31 into the left and right distribution chambers 37L and 37R.

A plurality of left intake branch pipes 38L and right intake branch pipes 38R, which communicate with the left and right distribution chambers 37L and 37R, are formed on the front wall of the intake distribution box 30 which faces the valleys 24.
Are integrally molded. Left and right intake branch pipes 38L,
One downstream connection flange 39 is integrally formed at the downstream end of the 38R and is connected to the left and right intake pipes 26L and 26R by bolts.

The left and right distribution chambers 37 are provided inside the intake distribution box 30.
Both partition chambers 37 are provided in the partition wall 35 which is divided into L and 37R.
A pair of upper and lower valve holes 40 that directly communicate between the L and 37R are provided, and a pair of butterfly-type on-off valves 41 that open and close the valve holes 40 are pivotally supported.

Thus, during operation of the engine E, the air flowing into the left and right inlets 20, 20 of the intake silencer 18 merges in the intake silencer 18, exits from the outlet 21, and enters the intake passage 22a of the throttle body 22. To the intake inlet 31 of the intake distribution box 30 of the intake manifold Mi. At that time, in the intake passage 22a, the intake amount of the engine E is controlled by the opening degree of the throttle valve 23.

In the low speed operation range of the engine E, the on-off valve 41 in the intake distribution box 30 is kept closed, and the air flowing into the intake inlet 31 of the intake manifold Mi has left and right distribution chambers 37L extending vertically. , 37R. Then, the air split into the left distribution chamber 37L is further split into a plurality of left intake branch pipes 38L, passes through the left intake pipe 26L, passes through the intake port 25L of the left bank 6L, and is sucked into the corresponding cylinder bore 27L. Further, the air branched to the right distribution chamber 37R is further branched to a plurality of right intake branch pipes 38R, passes through the right intake pipe 26R, passes through the intake port 25R of the right bank 6R, and is taken into the corresponding cylinder bore 27R.

By the way, in the low speed operation range of the engine E,
The left distribution chamber 37L and the right distribution chamber 37R, whose upstream ends of the left and right intake branch pipes 38L and 38R are open, have the upper intake inlet 3
Since it is closed by the on-off valve 41 in the closed state except the communication part with 1, the intake system from the left distribution chamber 37L to the intake port 25L of the left bank 6L and the intake system from the right distribution chamber 37R to the right bank 6R. Two resonance supercharging intake systems, which do not interfere with each other, are constructed by the intake system reaching the port 25R, and the natural vibrations of the resonance supercharging intake systems are each bank in the low speed operation range of the engine E. The 6L and 6R intake valves are set so as to substantially coincide with the opening / closing cycle of the intake valves. Therefore, the resonance supercharging effect is effectively exhibited, the intake charging efficiency in the low speed operation range of the engine is increased, and the output performance is improved. Can be planned.

Further, in the high speed operation range of the engine E, the opening / closing valve 41 in the intake distribution box 30 is opened, so that the left and right distribution chambers 37L and 37R communicate with each other through the valve holes 40. Since one surge tank having a large capacity is configured and the upstream ends of the left and right intake branch pipes 38L and 38R are opened to this surge tank, the capacity of the intake inertia in each bank 6L, 6R is increased, and the surge intake system of the resonance intake system is increased. The substantial length is reduced, and the natural frequency of the resonance intake system is increased so as to match the opening / closing cycle of the intake valves of the banks 6L and 6R in the high-speed operation range of the engine E, and the resonance supercharging effect is increased. Effectively demonstrated,
The intake charging efficiency in the high speed operation range of the engine E is increased, and the output performance can be improved.

As shown in FIGS. 5 to 8, the intake distribution box 30
Is a distribution box body 43 made of synthetic resin and a lid 44 made of high pressure die casting made of a light alloy such as Al alloy or Mg alloy.
Composed of and. The distribution box body 43 includes the connection flange 3
2, the left and right intake branch pipes 38L, 38R and one half portion 35a of the partition wall 35 are integrally formed.
On the rear wall opposite to L and 38R, the left and right distribution chambers 38L,
An opening 45 that opens across 38R is provided, and the periphery of the opening 45 is a joint flange 46 facing inward. The lid 44 closes the opening 45, and has a loop-shaped surrounding wall 47 that surrounds the opening 45 and faces the joint flange 46 on the inner surface and the partition wall 3.
5, the other half 35b is integrally formed, and the surrounding wall 47
A plurality of mounting bosses 47a are formed on the. Then, the enclosing wall 47 is sandwiched by the seal member 49, and the joint flange 4 is inserted.
6 and the mounting boss 47a is connected to the joint flange 46 with a bolt 51, so that the opening 4
5 is hermetically closed. At that time, one half 35 of the partition wall 35
The seal member 52 is also interposed between a and the other half portion 35b.

The pair of upper and lower valve holes 40 and the on-off valve 41 are provided in the other half 35b of the partition wall. Each valve hole 40 is formed in a rectangular shape with its long side oriented in the vertical direction and each corner being rounded. Correspondingly, each on-off valve 41 also has a similar rectangular shape. The pair of upper and lower on-off valves 41 are attached to a single common valve shaft 53 extending in the vertical direction, and the valve shaft 53 has three coaxial parts drilled from the lower end surface of the lid body 44 to the partition half part 35b. Both end portions and an intermediate portion are rotatably supported by the bearing holes 54a, 54b, 54c.

The both valve holes 40 are generally offset from the longitudinal center of the partition wall 35 to the lower end side which is the processing start end side of the bearing holes 54a, 54b and 54c. In this way, the span of the valve shaft 53 can be set to the minimum length required only for supporting the on-off valve 41, and the bearing hole 54
When processing a, 54b, 54c, it is possible to use a relatively short drill, and each bearing hole 54a, 54b, 54c
The processing accuracy of can be easily increased without requiring a high degree of skill. Further, the bearing holes 54a, 54b, 54c
Since the machining start end of (1) is located on the side opposite to the intake inlet 31, each bearing hole 54a, 54b, 54c can be easily and accurately machined with a relatively short drill regardless of the presence of the intake inlet 31.

Thus, the other half 3 of the partition wall integrated with the cover plate 98
Since the on-off valve 41 is pivotally supported by 5b, after the cover plate 98 and the on-off valve 41 are assembled, the cover plate 98 is fixed to the intake distribution box 30 so that the intake distribution box with the on-off valve 41 is attached. 30 can be assembled efficiently. In addition, a lid 44 that is joined to the joining flange 46 of the distribution box body 43
The loop-shaped surrounding wall 47 on the inner surface secures a necessary volume of the intake distribution box 30, and the lid body 44 together with the partition wall other half 35b.
Also functions as a reinforcing rib that strengthens the rigidity of the
It is possible to contribute to the reduction in the thickness of the lid body 44 and to the reduction in the weight thereof while preventing the warp after molding and the distortion due to the bolt tightening force on the distribution box body 43.

In particular, the lid body 44 having the valve hole 40 is smaller and simpler in shape than the distribution box body 43 integrated with the suction branch pipes 38L and 38R, so that precision casting such as high pressure die casting is possible. Become. Therefore, it is possible to easily obtain a high-quality lid body 44 that does not require post-processing of the valve hole 40, has high rigidity, and is free from distortion due to ambient temperature changes.

Further, the lid 44 has an enclosure wall 47 on its inner surface.
Since it is effectively reinforced by the bearing holes 54a, 54b, which are formed in the other half portion 35b of the partition wall which is integrated with the lid body 44,
54c does not deform, and the bearing holes 54a, 5a
The on-off valve 41, which supports the valve shaft 53 on the 4b and 54c, can be smoothly opened and closed regardless of changes in the ambient temperature. Further, the enclosure wall 47 on the inner surface of the lid 44 also serves to enlarge the molten metal passage during casting of the lid 44 and enhances the castability of the lid 44, thus contributing to the improvement of quality.

On the outer wall of the lid body 44, an outward bulging portion 44a is formed in a portion corresponding to the valve hole 40, and by forming the bulging portion 44a, the height of the partition half portion 35b is increased. hand,
The valve hole 40 having a large opening area can be formed. Further, the bulging portion 44a can increase the volume of the intake distribution box 30.

Further, in order to enable the molding of the valve hole 40, as shown in FIG.
The valve hole 40 is divided into a partition wall half body 55 and a partition wall piece 56 so that the valve hole 40 is divided by a surface orthogonal to the wall surface of each valve hole 40.
Is a U-shaped relatively deep notch 40a that opens in the dividing surface of the partition wall half body 55 and a U-shaped relatively shallow notch 40b that opens in the dividing surface of the partition wall piece 56. It is configured to match each other. At this time, the opposite side edges of the U-shaped comparatively deep notch 40a are provided with a taper θ in which the distance between the both sides increases toward the opening surface. On the other hand, U
The character-shaped relatively shallow notch 40b is rounded from its opening edge to the bottom surface. The on-off valve 41 has the above-mentioned valve hole 4
It goes without saying that it is formed in a shape corresponding to 0.
Both ends of the partition wall piece 56 are connected to the partition wall half body 55 with bolts 57 (see FIG. 12).

As is apparent from FIG. 14, the casting die 95 of the lid 44 is a female die 9 divided at the peripheral edge of the lid 44.
5b and a male die 95a, the male die 95a is provided with a molding projection 97 of the deep notch 40a.
Both side edges are provided with the same taper θ as the deep notch 40a. Thus, when the molds 95a and 95b are closed and the molten metal is poured into the cavity 96 defined between them to mold the lid 44, the deep notch 40a is formed into the male mold 95.
It is formed by the protrusion 97 of a. After casting, both molds 95a, 9
When 5b is opened, the taper θ attached to each side edge of the deep notch 40a and the projection 97 forms a die-cutting gradient, so that the mold release from the deep notch 40a can be easily performed. It is possible to obtain a precise deep notch 40a without scratches. By casting the partition wall piece 56 in the same manner, the shallow notch 40b can be precisely formed. Therefore, it is not necessary to perform troublesome valve hole processing after casting, and productivity can be improved.

In addition, a plurality of valve holes 40 are provided, and both end portions and intermediate portions of the valve shaft 53 common to the plurality of on-off valves 41 for opening and closing the valve holes 40 are provided with a plurality of bearing holes 54 of the partition half portion 35b.
Since it is supported by a, 54b, 54c, it is possible to set the total opening area of the valve hole 40 to be large and prevent the valve shaft 53 from being bent, and to ensure the smooth opening / closing operation of the opening / closing valve 41.

In FIGS. 9, 11 and 13, the lower end of the valve shaft 53 projects below the lid 44, and the operating lever 60 is fixed to the lower end. The actuating lever 60 includes three arms 60a, 60b, 60c arranged at intervals in the circumferential direction.
0a is a stopper protrusion 6 formed on the lower end surface of the lid 44.
The full open position of the open / close valve 41 is defined by abutting on the valve 1, and the full open position of the open / close valve 41 by abutting the second arm 60b on the stopper bolt 62 adjustably screwed to the stopper protrusion 61. Are specified. A valve spring 63 for urging the opening / closing valve 41 in the opening direction is connected to the operating lever 60. Therefore, the opening / closing limit of the opening / closing valve 41 can be accurately defined without providing the stopper means in the actuator 64, and the stopper protrusion 97 is integrated with the lid body 44 to simplify the structure and to reduce the valve hole 40. Combined with the simple formation of the, it can greatly contribute to cost reduction.

The operating rod 65 of the negative pressure actuator 64 is connected to the third arm 60c. The negative pressure actuator 64 divides the interior of the casing 66 into an atmosphere chamber 69 and a working chamber 70 by a casing 66 supported by a bracket 67 screwed to the lower surface of the lid 44, and connects the outer peripheral edge to the casing 66. The operating rod 65 is fixed to the center of the diaphragm 71 through the atmosphere chamber 69 and pivotally connected to the third arm 60c. In the working chamber 70, a return spring 7 for urging the diaphragm 71 in the opening direction of the opening / closing valve 41 is provided.
Two are accommodated.

Casing 66 of negative pressure actuator 64
A negative pressure introducing pipe 73 connected to the negative pressure chamber,
A control 76 is provided in the middle of a negative pressure conduit 75 connecting this and the negative pressure tank 74. This control 76 is composed of a solenoid valve, and is excited by the control of an electronic control unit (not shown) to make the negative pressure conduit 75 conductive in the low speed operation range of the engine E, and demagnetized in the high speed operation range to make the negative pressure conduit 75 open. The negative pressure chamber of the negative pressure actuator 64 is opened to the atmosphere while being cut off. Therefore, in the low speed operation range of the engine E, the negative pressure actuator 64 operates to close the opening / closing valve 41, and in the high speed operation range, the negative pressure actuator 64 becomes inoperative. It will be opened by biasing force.

The negative pressure tank 74 is connected with a negative pressure conduit 79 connected to a negative pressure take-out pipe 78 formed in the upper portion of the intake distribution box 30. In the middle of the negative pressure conduit 79, the negative pressure tank 74 is connected to the negative pressure tank 74. A check valve 80, which blocks the reverse flow of negative pressure to the negative pressure extraction pipe 78, is provided. Therefore, during operation of the engine E, the intake negative pressure generated in the intake distribution box 30 is transferred to the negative pressure tank 7 through the negative pressure conduit 79 and the check valve 80.
Can be stored in 4.

As shown in FIGS. 9 and 10, on the lower end surface of the lid body 44, an annular seal housing 82 adjacent to the outer end of the lowermost bearing hole 22a, and further, the seal housing 8 is provided.
A washer housing 83 is formed adjacent to the outer end of 2. The seal housing 82 includes an annular seal member 84.
Is installed. The washer housing 83 accommodates a clip 85 that is locked to the outer periphery of the valve shaft 53 and faces the outer end surface of the seal member 84, and one or a plurality of washers 86 that abut on the clip 85 in a rotatable and slidable manner. The pressing plate 87 for preventing the washer 86 from coming off is attached to the lid 4
4 is screwed to the lower surface. The seal member 84 is made of an elastic material such as rubber. The inner peripheral surface of the seal member 84 is integrally provided with a pair of seal lips 84a, 84b which project in directions away from each other and come into close contact with the outer peripheral surface of the valve shaft 53. On the outer peripheral surface, a metallic reinforcing ring 89 is press-fitted into the inner peripheral surface of the seal housing 82.

Thus, even when the intake pulsation, that is, the pressure fluctuation in which the negative pressure and the positive pressure are alternately repeated is generated in the intake distribution box 30 during the operation of the engine E, the seal lip 84a of the seal member 84, The 84b surely prevents outside air from entering the intake distribution box 30 or leaking the pressure in the intake distribution box 30 through the lowermost bearing hole 54a, and prevents dust from entering the intake air intake distribution box 30. It is possible to avoid intrusion and leakage of fuel, blow bio-oil, etc. at the time of blowback.

As shown in FIG. 13, the actuator 64
Are arranged so as to be included in the downward projection pattern of the intake distribution box 30. At that time, in order to avoid the interference of the actuator 64 with the intake distribution box 30, as shown in FIGS. 6 and 11, the actuator 64 is attached to the lower surface of the intake distribution box 30.
A recess 90 is formed to receive the top of the.

The position of the actuator 64 for driving the opening / closing valve 41 to open / close can be freely set around the valve shaft 53 by selecting the connecting position of the operating lever 60 to the valve shaft 53 of the opening / closing valve 41. The actuator 64 and the engine hood 12 close to the rear surface of the intake distribution box 30 can be accommodated within the region of the vertical projection pattern of the intake distribution box 30 simply by tilting the actuator 64 forward. It is possible to easily avoid the interference with the rear wall. Moreover, since the intake inlet 31 and the actuator 64 are arranged at the upper and lower ends of the intake distribution box 30, their interference can be avoided and the intake device can be made compact. Moreover, by allowing the recess 90 on the lower surface of the intake distribution box 30 to receive the upper portion of the actuator 64, the relatively large actuator 64 can be installed in a small engine room without interfering with the intake distribution box 30 or the engine hood 12.

Although the embodiments of the present invention have been described in detail above, the present invention can be modified in various ways without departing from the scope of the invention. For example, the partition piece 56 may be omitted, and the shallow notch 40b may be formed in the half portion 35a of the partition 35 on the distribution box body 43 side at the time of molding. The present invention can also be applied to a variable intake system for an automobile engine.

[0047]

As described above, according to the first feature of the present invention, the intake distribution box is provided with the intake inlet connected to the intake passage of the throttle body, and the inside of the intake distribution box is provided with the partition wall to the intake inlet. First and second intake branch pipes that are divided into first and second distribution chambers that communicate with each other, respectively open to the first and second distribution chambers, and respectively communicate with the intake ports of the first and second banks of the engine. A valve hole that is connected to the intake distribution box and that connects the partition wall to the first and second distribution chambers;
A butterfly type on-off valve for opening and closing this valve hole is provided, and in a variable intake system of a multi-cylinder engine, one of the dividing surfaces of the partition wall, which is divided by a surface orthogonal to the wall surface of the partition wall, is molded and faces each other. A U-shaped deep notch formed on both side edges so that the distance between the both edges widens toward the opening surface, and a U-shape formed on the other divided surface so that the deep notch and the opening surface are aligned with each other. Since the valve hole is composed of a shallow notch, a deep notch and a shallow notch are formed even when the intake device is divided by a surface orthogonal to the wall surface of the partition wall having the valve hole in molding. When molding the part with the notch,
The valve hole can be easily formed by forming the notches at the same time and aligning their opening surfaces with each other. In particular, since the deep notch is tapered on both side edges facing each other so that the distance between the both sides increases toward the opening surface, it is easy to release from the notch at the time of molding. ，
After molding, it is possible to obtain a precise valve hole without scratches on the inner surface without performing a troublesome valve hole finishing process, and it is possible to improve productivity.

According to the second feature of the present invention, in addition to the first feature, since the partition wall portion having the deep notch and the shallow notch respectively is made by casting, the deep notch and the shallow notch are formed. It is possible to reliably prevent the thermal distortion of the partition wall portion having each notch, and therefore the deformation of the valve hole, and always ensure the proper opening / closing function of the opening / closing valve.

[Brief description of drawings]

FIG. 1 is an overall side view of an outboard motor according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of FIG.

3 is a sectional view taken along line 3-3 of FIG.

4 is a sectional view taken along line 4-4 of FIG.

5 is a sectional view taken along line 5-5 of FIG.

6 is a sectional view taken along line 6-6 of FIG.

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

FIG. 8 is an exploded view of a main part of the intake manifold corresponding to FIG.

9 is a sectional view taken along line 9-9 of FIG.

FIG. 10 is an enlarged view of part 10 of FIG.

FIG. 11 is a view on arrow 11 of FIG.

12 is a sectional view taken along line 12-12 of FIG.

13 is a sectional view taken along line 13-13 of FIG.

FIG. 14 is a cross-sectional view showing a method for casting a lid.

[Explanation of symbols]

E ... Engines 6L, 6R ... First and second banks (left and right banks) 22 ... Throttle body 22a ... Intake passages 25L, 25R ... First and second intakes Ports (left and right intake ports) 30 ... Intake distribution box 31 ... Intake inlet 35 ... Partition wall 35a ... Partition half half 35b ... Partition other half 37L, 37R ... First and second distribution chambers (left and right distribution chambers) 38L, 38R ... First and second intake branch pipes (left and right intake branch pipes) 40 ... Valve hole 40a ... Deep notch 40b ... Shallow notch 41 ... Open / close valve 55 ... Partition wall part having deep notch (mainly partition wall and other half part) 56 ... Partition wall part having shallow notch (partition piece 5
6)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02M 35/10 301R F term (reference) 3G031 AA05 AA28 AB07 AC03 BA08 BA14 BA18 BB11 DA05 DA28 DA32 DA37 EA02 FA03 GA05 GA13 HA01 HA04 HA10

Claims (2)

[Claims] 1. An intake distribution box (30) having an intake inlet (3) connected to an intake passage (22a) of a throttle body (22).
1) is provided, and a partition wall (35) is provided inside the intake distribution box (30).
To connect the intake inlet (31) with the first
And the second distribution chambers (37L, 37R), and the first and second distribution chambers (37L, 37R) are opened respectively to the first and second banks (6L, 6R) of the engine (E).
First connected to each intake port (25L, 25R)
And the second intake branch pipes (38L, 38R) are connected to the intake distribution box (30), and the partition wall (35) communicates between the first and second distribution chambers (37L, 37R). Four
0) and a butterfly-type on-off valve (41) for opening and closing the valve hole (40), in a variable intake device for a multi-cylinder engine, the variable intake device being divided by a plane orthogonal to the wall surface of the partition wall (35). A U-shaped deep notch (4) is formed on one of the dividing surfaces of the partition wall (35) and has a taper (θ) on both opposite edges so that the distance between the opposite edges increases toward the opening surface.
0a) and a U-shaped shallow notch (4) that is molded on the other split surface and that aligns the opening with the deep notch (40a).
0b) and the valve hole (40) are configured with the variable intake device for a multi-cylinder engine. 2. The variable intake system for a multi-cylinder engine according to claim 1, wherein the partition walls (55, 5) each have the deep notch (40a) and the shallow notch (40b).
A variable intake system for a multi-cylinder engine, characterized in that 6) is made by casting.