JP3946810B2 - Outboard motor intake passage structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intake passage structure for an outboard motor.
[0002]
[Prior art]
Conventionally, an outboard motor has been detachably attached as a propulsion device to the stern portion of a small vessel. In this outboard motor, an engine main body, a carburetor, and other auxiliary machines are arranged at the upper part. For this reason, the upper structure portion has a shape protruding in the width direction and the length direction.
[0003]
[Problems to be solved by the invention]
The outboard motor performs so-called tilt-up in order to lift the lower propeller onto the water in the state of being attached to the hull. At that time, the upper structure portion is inserted into the concave portion of the stern portion. The shape of this is subject to restrictions, and for the convenience of carrying for storage, it is desired to have a compact configuration as much as possible. The most important issue for the downsizing of the upper part is how to arrange the carburetor with respect to the cylinder body of the engine. For example, in Japanese Patent Application Laid-Open No. 60-38293, the cylinder portion of the engine is arranged so that the cylinder axis is inclined to the left or right in plan view with respect to the axis in the propulsion direction, and the side space formed by this arrangement The carburetor is arranged on the front and rear so that the length in the front-rear direction is not increased by the carburetor.
[0004]
However, when the cylinder body of the engine is inclined and arranged as described above, a new problem arises that various restrictions are imposed on the arrangement of other auxiliary machines.
[0005]
The present invention has been made to solve such a conventional problem. An outboard motor in which the upper structure of the outboard motor has a compact configuration without the cylinder body being inclined. An intake passage structure is provided.
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention, the starter is disposed on the upper side of the engine of the outboard motor, and the carburetor is disposed on the engine head on the rear side . The carburetor is inclined with respect to the cylinder direction of the engine in plan view. A silencer, which is an intake pipe, is coupled to one side of the carburetor and extends below the carburetor. An intake port is opened at the lower end of the carburetor, and an intake manifold is formed on the other side of the carburetor. They are combined, curved in a U shape, and led to the cylinder head below .
[0007]
According to the first aspect of the present invention, the carburetor is disposed in the dead space generated on the engine head on the rear side of the starter, so that the dead space can be effectively used to make the superstructure of the outboard motor compact. .
[0008]
In addition, since the carburetor is inclined with respect to the cylinder direction of the engine in plan view, the amount of the silencer and intake manifold projecting in the width direction on both sides of the carburetor is reduced, thereby reducing the installation width of the carburetor. Since it can be made narrow, the outboard motor upper part can be made into a more compact configuration.
[0009]
In addition, a silencer, which is an intake pipe, is connected to one side of the carburetor and extends below the carburetor. Since the intake port is open at the lower end of the carburetor, the intake port of the carburetor is located below the carburetor. The cold air can be taken into the carburetor, and since the silencer extends downward, water is prevented from entering the carburetor.
[0010]
In addition, an intake manifold is connected to the other side of the carburetor, curved in a U-shape and guided to the cylinder head below it, so that the conventional structure for guiding the intake manifold linearly from the carburetor to the engine is adopted. In comparison, since the length of the intake manifold becomes longer, the oil adhering to the wall surface can be evaporated by the heat of the wall surface and mixed into the intake air, and the fuel can be vaporized well.
[0011]
According to a second aspect of the present invention, an air vent hole is formed in the cowling on the upper side of the carburetor.
[0012]
In the invention of claim 2 , since the air vent hole is formed on the upper side of the carburetor, the air from the lower side can flow toward the upper air vent hole, and the carburetor is cooled by this flow. In particular, this cooling function is effective when the engine is stopped and the engine coolant is stopped.
[0013]
According to a third aspect of the present invention, the outer tube of the throttle operation wire and the choke operation wire of the carburetor is held by attaching its tip to the carburetor body.
[0014]
According to the third aspect of the invention, the outer tube of the throttle operation wire and the choke operation wire is held by the connection destination at the tip thereof, so that the holding structure can be simplified.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The outboard motor 100 is attached to a hull stern (not shown) on the left side (front side) of FIG. 1, and the upper structure of the outboard motor 100 is disposed in a cowling 9 formed by an upper cowling 91 and a lower cowling 92. The cylinder body 1 of the engine is installed so that the crankshaft 13 faces in the vertical direction, and the rotational torque of the crankshaft 13 is installed horizontally at the lower end of the outboard motor via a drive shaft (not shown) extending downward. It is transmitted to the propeller shaft to drive the propeller to rotate.
[0016]
A cylinder head 11 is coupled to the cylinder body 1 on the rear side (right side in FIG. 1), a cylinder head cover 12 is coupled to the rear side thereof, a fuel tank 4 is disposed on the front side of the cylinder body 1, and a cylinder tank 1 is disposed on the lower side. An oil pan 10 is formed integrally with the crankcase 7. A manual starter 3 is disposed above the cylinder body 1, and a carburetor 2 is disposed above the cylinder head 11 on the rear side. The carburetor 2 is disposed so as to be inclined with respect to the cylinder direction of the engine in plan view. An operation handle 32 for the starter 3 is formed so as to protrude to the front side of the cowling 9.
[0017]
A silencer 21 as an intake pipe is coupled to one side of the carburetor 2 and extends downward, and an intake port 23 is opened at a lower end thereof. An intake manifold 22 is coupled to the other side portion of the carburetor 2, and the intake manifold 22 is bent in a U shape and led to the cylinder head 11 on the lower side. An air vent hole 98 is formed in the upper cowling 9 on the upper side of the carburetor 2.
[0018]
A base end portion of the steering handle 5 is attached to one side portion of the cowling 9, and the steering handle 5 extends forward, and a throttle operation grip 51 is formed at the tip end portion. A throttle wire 55 operated by the grip 51 is led from the steering handle 5 through the outer tube 50 in the cowling 9 to the carburetor 2. The outer tube 50 passes through the front side of the cylinder body 1 and is guided from the other side portion to the front side portion of the carburetor 2, and the distal end portion thereof is held by a part of the main body of the carburetor 2. A choke knob 8 is attached to one side of the front side of the cowling 9, and a choke operating wire 85 operated by the choke knob 8 is guided to the carburetor 2 through the outer tube 80 in the cowling 9. The distal end portion of the outer tube 80 is held by a part of the main body of the carburetor 2.
[0019]
As shown in FIGS. 4 to 6, the distal end portion of the outer tube 80 is held by being fitted into a through hole 82 formed in the attachment portion 25 that forms a part of the main body of the carburetor 2. Only 85 is penetrated so as to be movable in the axial direction, and its tip is connected to the choke lever 83. In FIG. 6, only the attachment portion of the outer tube 80 is shown, but the distal end portion of the outer tube 50 is also held by the attachment portion 25 with the same structure, and the distal end portion of the wire 55 is connected to the throttle lever 53. .
[0020]
Further, as shown in FIGS. 7 and 8, the camshaft 14 is disposed on one side of the cowling 9 in the vicinity of the central portion in the front-rear direction, and the fuel pump 41 is disposed in the width direction outside the camshaft 14. A carrying handle 6 is formed so as to surround the cowling 9.
[0021]
In the above configuration, the carburetor 2 is disposed in the dead space generated on the rear side of the starter 3 and above the engine head 11, so that the dead space is effectively used to make the upper structure of the outboard motor compact. In addition, since the carburetor 2 is disposed to be inclined with respect to the cylinder direction of the engine in plan view, the amount of the silencer 21 and the intake manifold 22 on both sides of the carburetor 2 projecting in the width direction is reduced, and thereby the carburetor 2 Since the installation width of 2 can be narrowed, the superstructure of the outboard motor 9 can be made more compact.
[0022]
That is, when the carburetor 2 is disposed on the side of the cylinder body 1 as shown in FIG. 9, the cowling 9 protrudes laterally from the side, and the carburetor 2 is mounted on the cylinder as shown in FIG. If the silencer 21 is arranged on the upper side of the head 11 without being inclined in a plan view, the silencer 21 protrudes to the side of the cowling 9, and the width of the cowling 9 needs to be increased. Therefore, by arranging the carburetor 2 so as to be inclined with respect to the cylinder direction of the engine in plan view as described above, the outboard motor can be made compact.
[0023]
The silencer 21 is arranged in a dead space on one side of the carburetor 2. That is, the width of the cowling 9 is made as narrow as possible under the restriction of the internal structure. However, as shown in FIGS. 7 and 8, the camshaft 14 and the fuel pump 41 are arranged in the width direction. Therefore, the width of the upper cowling 91 is particularly determined by these. In this embodiment, the width of the cowling 9 is determined by the arrangement of the camshaft 14 and the fuel pump 41. As a result, a dead space is generated on one side of the carburetor 2 on the rear side of the fuel pump 41. A silencer 21 is disposed on the side. Outer tubes 50 and 80 for guiding wires for throttle operation and choke operation are arranged in the space above the fuel pump 41.
[0024]
Further, as shown in FIG. 2, since the air inlet 23 of the carburetor 2 is located below the carburetor 2, cold air can be taken in, and since the silencer 21 extends downward, water enters the carburetor 2. This has the effect of preventing Further, the intake manifold 22 is bent in a U shape and led to the lower engine, and the length of the intake manifold 22 is longer than the conventional structure in which the intake manifold is linearly guided from the carburetor 2 to the engine. The oil adhering to the wall surface can be evaporated and mixed in the intake air by the heat of the wall surface, and the fuel can be vaporized well. That is, since the intake manifold 22 is made of aluminum and has a good thermal conductivity, the gasoline adhering to the pipe wall is heated. For this reason, the evaporation time of the gasoline becomes long and the evaporation time of the gasoline becomes long.
[0025]
Moreover, since the air vent hole 98 is formed on the upper side of the carburetor 2, the hot air 93 does not accumulate on the upper side of the carburetor 2, and the air from the lower side can flow toward the upper air vent hole 98. Since the carburetor 2 is cooled, this cooling function works effectively particularly when the engine is stopped and the engine coolant is stopped. Furthermore, since the outer tubes 50 and 80 of the throttle operation wire and the choke operation wire are held by the connection destination of the tip portion, the holding structure can be simplified.
[0026]
Further, since the OHV structure has a feature that there is no camshaft timing belt on the side of the engine and there is a sufficient space, the above structure is suitable for making a compact structure when applied to the OHV structure.
[0027]
【The invention's effect】
According to the first aspect of the present invention, the carburetor is disposed in the dead space generated on the engine head on the rear side of the starter, so that the dead space can be effectively used to make the superstructure of the outboard motor compact. .
[0028]
In addition, the amount of protrusion of the silencer and intake manifold on both sides of the carburetor is reduced in the width direction, thereby reducing the installation width of the carburetor. it can.
[0029]
Further, since the intake port of the carburetor is positioned below the carburetor, it is possible to take in cold air, and further, since the silencer extends downward, there is an effect of preventing water from entering the carburetor.
[0030]
Compared to the conventional structure in which the intake manifold is guided linearly from the carburetor to the engine, the length of the intake manifold is increased, so that the oil attached to the wall surface is evaporated by heat of the wall surface and mixed into the intake air. Therefore, fuel can be vaporized well.
[0031]
In the invention of claim 2 , since the air vent hole is formed on the upper side of the carburetor, the air from the lower side can flow toward the upper air vent hole, and the carburetor is cooled by this flow. In particular, this cooling function is effective when the engine is stopped and the engine coolant is stopped.
[0032]
According to the third aspect of the invention, the outer tube of the throttle operation wire and the choke operation wire is held by the connection destination at the tip thereof, so that the holding structure can be simplified.
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of the present invention.
FIG. 2 is a rear view of FIG.
FIG. 3 is a side view of FIG. 1;
4 is a view taken in the direction of arrow A in FIG.
FIG. 5 is a view taken in the direction of arrow B in FIG. 1;
6 is an enlarged view of a portion C in FIG. 1. FIG.
7 is a cross-sectional view taken along the line DD of FIG.
8 is a cross-sectional view taken along the line EE of FIG.
FIG. 9 is a view corresponding to FIG. 1 showing a contrast example of carburetor arrangement.
FIG. 10 is a view corresponding to FIG. 1, showing another contrast example of the carburetor arrangement.
[Explanation of symbols]
1 Cylinder Body 2 Carburetor 3 Starter 4 Fuel Tank 5 Steering Handle 6 Carrying Handle 7 Crankcase 9 Cowling 10 Oil Pan 11 Cylinder Head 12 Cylinder Cover 13 Crankshaft 14 Camshaft 21 Silencer 22 Intake Manifold 23 Carburetor Inlet 41 Fuel Pump 50 Outer tube for throttle operation 55 Wire for throttle operation 80 Outer tube for choke operation 85 Wire for choke operation 98 Air vent hole

Claims (3)

A starter is arranged on the upper side of the engine of the outboard motor, and a carburetor is arranged on the engine head on the rear side .
The carburetor is inclined with respect to the cylinder direction of the engine in plan view,
A silencer, which is an intake pipe, is coupled to one side of the carburetor and extends below the carburetor.
An intake passage structure for an outboard motor , wherein an intake manifold is coupled to the other side portion of the carburetor, is curved in a U shape, and is led to a cylinder head below the U. 2. An outboard motor intake passage structure according to claim 1 , wherein an air vent hole is formed in the cowling above the carburetor. The outboard motor intake passage according to claim 1 or 2 , wherein the outer tube of the throttle operation wire and the choke operation wire of the carburetor is held by attaching a tip portion thereof to the carburetor body. Construction.

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