JP3134553B2 - Outboard motor intake pipe structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake pipe structure of an outboard motor, and more particularly to an intake pipe structure of an outboard motor which can be reduced in size and improved in output.

[0002]

2. Description of the Related Art In an outboard motor equipped with a fuel injection type four-cycle engine, each intake branch pipe of an intake manifold is disposed along the side surface of a cylinder block of the engine in order to supply intake air to the engine. The intake pipe structure has a surge tank for distributing intake air on the upstream side of each intake branch pipe. The engine is covered by a removable engine cover and an under cover attached to a lower portion of the engine cover.

[0003] Such an outboard motor is disclosed, for example, in JP-A-2-274690.
According to this publication, corresponding intake and fuel supply systems are mounted laterally on the side of an engine in which cylinders are arranged in rows in a casing. The upper end of the device is configured to be located below the rotation plane of the flywheel and above the engine block, thereby fully utilizing the output of the engine and effectively utilizing the limited space in the lateral direction, This is to make the entire outboard motor compact.

[0004]

However, in the intake pipe structure described in the above publication, the carburetor is located on the side of the engine, so that there is a disadvantage that the engine cover becomes large.

Further, in an engine provided with a carburetor, if the length of the intake manifold is increased, the supply of fuel is delayed, so that the length of the intake manifold is reduced to the length of the intake manifold described in the above-mentioned publication. turn into. However, with the intake manifold having such a length, there is a disadvantage that the intake air does not synchronize with the inertia within the normal engine speed, and thus the output decreases.

Further, the throttle valve axis of the throttle valve of the carburetor is oriented in the horizontal direction, and the characteristics of the throttle opening cannot be obtained without using a cam.

[0007]

SUMMARY OF THE INVENTION Therefore, in order to eliminate the above-mentioned disadvantages, the present invention provides a flywheel at an upper end of a crankshaft of an engine and an intake manifold along a side surface of a cylinder block of the engine. In the intake pipe structure of an outboard motor provided with an intake branch pipe, a surge tank section provided upstream of the intake manifold, and an engine cover and an under cover for covering the engine and the intake manifold, the surge tank section is provided. Is disposed between the flywheel and the undercover and further forward of the outboard motor than the crankcase of the engine.

[0008]

According to the structure of the present invention, since the surge tank is disposed between the flywheel and the undercover and in front of the outboard motor with respect to the engine crankcase, each intake branch pipe of the intake manifold is provided. By increasing the length, the inertia intake can be performed within the normal engine speed, and the output can be improved, the capacity of the surge tank portion can be secured, and the size can be reduced.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; 1 to 6 show an embodiment of the present invention. 4 to 6, reference numeral 2 denotes a fuel injection type outboard motor. The outboard motor 2 includes a water-cooled four-cycle engine 4, a drive shaft 6 connected to the engine 4, and a propeller 10 connected to the drive shaft 6 via a gear mechanism 8.

The engine 4 is covered with a removable engine cover 12 and an under cover 14 for supporting the engine cover 12 at a lower portion.

The drive shaft 6 is covered by a drive shaft housing 16.

The gear mechanism 8 is covered by a gear case 18.

The engine 4 includes a cylinder block 20
And a cylinder head 22. In the cylinder block 20, a crankshaft 24 is supported, and four cylinders 26 are provided in parallel. Also, in the cylinder block 20, the crankshaft 24 is covered.
A crankcase 28 is provided continuously.

Each cylinder 26 is mounted on the crankshaft 24.
One end of each connecting rod 30 is connected correspondingly. The other end of each connecting rod 30 has a cylinder 2
Each piston 32 provided in 6 is connected. Also,
At the upper end of the crankshaft 24, as shown in FIGS.
A flywheel 36 is mounted on the crank pulley 34 and above the crank pulley 34 as a part of the magneto.

A camshaft 38 is provided on the cylinder head 22.
Is supported. A cam pulley 40 is attached to the upper end of the cam shaft 38 corresponding to the crank pulley 34. The cam pulley 40 and the crank pulley 3
4, a timing belt 42 is wound around.

One end of the drive shaft 6 is connected to the other end of the crankshaft 24.

The gear mechanism 8 is connected to the other end of the drive shaft 6. The propeller 10 is connected to the gear mechanism 8.

As shown in FIG. 2, the cylinder head 22 is formed with each intake port 46 and each exhaust port 48 opening to each combustion chamber 44. Each intake port 46 communicates with each intake passage 54 formed in each intake branch pipe 52 of the intake manifold 50 attached to the cylinder head 22. Each exhaust port 48 has an exhaust passage wall 56.
Are connected to each other. Each intake branch pipe 52 of the intake manifold 50 is disposed along the side surface of the cylinder block 20, as shown in FIGS. Further, each exhaust passage 58 is communicated with the exhaust collecting part 60.

Each of the combustion chambers 4 is provided with the cylinder head 22.
4, each ignition plug 62, each intake valve 64 for opening and closing each intake port 46, and each exhaust valve 66 for opening and closing each exhaust port 46 are provided.

Each fuel injection valve 68 is attached to each intake branch pipe 52 of the intake manifold 50 so as to face each intake port 46.

A surge tank 70 for distributing intake air is provided upstream of the intake manifold 50.

The surge tank 70 includes a throttle valve shaft 7.
Throttle body 7 having throttle valve 74 fixed to 2
6 is mounted.

On the upstream side of the throttle body 76,
A throttle guide 78 is attached. The throttle guide 78 has an engine cover 1 on the rear side of the outboard motor 2.
The air taken in from the air inlet 80 formed in 2 flows in as intake air.

As shown in FIGS. 1 and 3, the surge tank 70 is provided between the flywheel 36 and the undercover 14, that is, below the flywheel 36 and above the upper end surface 14a of the undercover 14. Further, as shown in FIGS. 1 and 2, the engine 4 is disposed in front of the outboard motor 2 with respect to the crankcase 28 of the engine 4.

As shown in FIGS. 1 and 2, a remote control lever (horizontal axis) 82 operating vertically and a throttle valve shaft 72 moving vertically (vertical axis) are provided on the bottom side of the surge tank 70. A bell crank 84 for connection is provided.

Next, the operation of this embodiment will be described.

The air taken in from the air inlet 80 is
The air flows in from the throttle guide 78 as intake air, is distributed by the surge tank 70 through the throttle body 76, and is supplied to each combustion chamber 44 through each intake passage 54.

Incidentally, each intake branch pipe 52 of the intake manifold 50 is connected to each intake port (not shown) of the cylinder head 22.
In any case, the fuel is at a high position regardless of the position, so that the backflow of the fuel can be prevented.

Further, as shown in FIGS. 1 and 2, the surge tank 70 is disposed in front of the crankcase 28, so that the side direction is reduced, and the size of the engine 4 can be reduced. Further, since each intake branch portion 52 can be lengthened, inertia tuning can be performed on the intake air, and the output can be improved within the normal engine speed. Further, the throttle body 76 is connected to the air inlet 80 of the engine cover 12.
From the throttle body 7
6 can be prevented from being splashed with water.

Also, as shown in FIG.
0, a bell crank 84 that connects a remote control lever (horizontal axis) 82 that operates in the vertical direction and a throttle valve 70 that moves in the horizontal direction (vertical axis) is provided. The characteristics can be non-linear, thereby making it easier for the driver to maneuver.

[0031]

As is apparent from the above detailed description, according to the present invention, the surge tank is disposed between the flywheel and the undercover and in front of the outboard motor with respect to the engine crankcase. Each intake branch pipe of the intake manifold can be lengthened to perform inertial intake within the normal engine speed, thereby improving the output, securing the capacity of the surge tank, and achieving compactness.

[Brief description of the drawings]

FIG. 1 is a side view of an engine in an outboard motor.

FIG. 2 is a sectional view of the outboard motor taken along the line II-II of FIG.

FIG. 3 is a schematic front view of the engine indicated by an arrow の in FIG. 6;

FIG. 4 is a side view of the outboard motor.

FIG. 5 is a rear view of the outboard motor indicated by an arrow の in FIG. 4;

FIG. 6 is a sectional view of the outboard motor taken along line II-II of FIG.

[Explanation of symbols]

 2 Outboard motor 4 Engine 6 Drive shaft 8 Gear mechanism 10 Propeller 12 Engine cover 14 Under cover 20 Cylinder block 22 Cylinder head 28 Crank case 36 Flywheel 50 Intake manifold 70 Surge tank section 82 Remote control lever 84 Bell crank

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuyuki Shomura 300 Takatsukacho, Hamamatsu-shi, Shizuoka Suzuki Co., Ltd. (72) Inventor Hidehiko Yoshioka 300 Takatsukacho, Hamamatsu-shi, Shizuoka Suzuki Co., Ltd. (72 ) Inventor Jiro Saiga 300 Suzuki Corporation, Takatsuka-cho, Hamamatsu-shi, Shizuoka Prefecture (56) References JP-A-3-172570 (JP, A) JP-A-2-274690 (JP, A) JP-A-61- 57491 (JP, A) JP-A-58-106162 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B63H 20/00 F02B 67/00 F02M 35/104 F02M 35/16

Claims (1)

(57) [Claims] 1. A flywheel is provided at an upper end of a crankshaft of an engine, each intake branch pipe of an intake manifold is provided along a side surface of a cylinder block of the engine, and a surge tank is provided upstream of the intake manifold. In the intake pipe structure of an outboard motor provided with an engine cover and an under cover that cover the engine and the intake manifold,
An intake pipe structure for an outboard motor, wherein the surge tank is disposed between the flywheel and the undercover and in front of the outboard motor with respect to a crankcase of the engine.