JPH05332214A - Intake system of outboard engine - Google Patents

Abstract

PURPOSE:To provide an intake system of an outboard engine in which intake air can be uniformly distributed to the combustion side, the occurrence of white smoke in driving the engine due to turbid fuel generated in tilt-up, etc., of the engine can be prevented and further the structure of a surge tank is more simplified. CONSTITUTION:While air taken in from a throttle body is adapted to be supplied to a surge tank 14, a guide 20 having an axially spiral shape is provided in the surge tank. Air introduced in the surge tank can flow in the tank along the spiral of the guide 20 so that air can be uniformly distributed to a crank chamber. While the intake air is supplied through a reed valve 18 into the crank chamber, a fuel reservoir in tilt-up or the like is provided below the reed valve to prevent fuel from abrupt outflow to the combination side. Further, an idle speed control means for bypassing air taken in from the throttle body is provided and a specially shaped sheet rubber is provided between the control means and the surging tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for an outboard motor, and more particularly to improvement of a flow passage structure between the intake air of a throttle body and the combustion side.

[0002]

2. Description of the Related Art Conventionally, a suction tank of an outboard motor is provided with a surge tank having a constant volume for supplying air required for each combustion chamber between a throttle body and a crankcase. In addition, the carburetor type intake device has a configuration in which one carburetor is provided for each cylinder or two cylinders to avoid variations in the air supply amount between the cylinders.

[0003]

However, in the case of an outboard engine, the number of throttle bodies is usually one, and in the case of a vertical multi-cylinder engine, the engine speed increases and a large amount of air is consumed. When the amount is required, if the inlet manifold and the surge tank are small, the air flowing through each reed valve will have individual variations, which will adversely affect the engine performance. Therefore, it is conceivable to increase the volume of the surge tank, but in this case, there is no choice but to increase the size of the engine itself, and especially in the case of an outboard engine engine that is required to be downsized. There was the inconvenience of being inappropriate.

By the way, in the engine for the outboard motor,
Fuel supplied to the crankcase near the reed valve may flow and accumulate near the reed valve when tilting up, and this is suddenly supplied to the combustion side when the engine is operating and causes white smoke due to changes in fuel concentration. Becomes In order to prevent this, the accumulated fuel is extracted via a check valve so that it is not supplied to the combustion side during acceleration, but in this case a special pipe for extraction is required in addition to the check valve. However, there is a problem in space, and it is not preferable because it may cause a failure of the check valve.

In this type of intake device, idle speed control means for bypassing the air taken in by the throttle valve and supplying it to the surge tank is provided to adjust the air amount during idling. Although the method has been taken, the air flow path structure of the idle speed control means is such that the idle speed control means is connected to the surge tank 53 via the seat rubber 52 as shown in FIG. ing. The surge tank 53 is provided with an air suction hole 53A communicating with the hole 54 to which the air from the throttle body is supplied, and an air discharge hole 53B. For this reason, there is also a disadvantage that the shape of the surge tank 53 is complicated.

[0006]

SUMMARY OF THE INVENTION The first object of the present invention is to make it possible to uniformly supply intake air to the combustion side, and to reduce the size of the surge tank while eliminating the cause of engine performance deterioration. To provide an intake device for an outboard motor.

Another object of the present invention is to temporarily store the accumulated fuel generated when the outboard motor is tilted up, and to suppress the increase in the fuel ratio when the engine is driven as much as possible to prevent white smoke. An object of the present invention is to provide an outboard motor intake device that can be prevented.

It is still another object of the present invention to provide an outboard motor intake system which can further simplify the structure of the surge tank.

[0009]

According to the present invention, a throttle body and a surge tank communicating with the throttle body via an inlet manifold are provided, and air introduced into the surge tank is passed through a reed valve. In the intake device of the outboard motor provided so as to be able to supply to a plurality of combustion sides, a configuration is provided in which a guide for distributing air to each combustion side is provided in the surge tank. The amount of air supplied is made uniform, and it is expected that good engine performance will be achieved.

Further, according to the present invention, a fuel reservoir is formed below the reed valve so that fuel from the crank chamber can be temporarily stored when the outboard motor is tilted up and the like. It is intended to prevent the generation of white smoke by preventing the fuel from being burned all at once and keeping the fuel ratio as constant as possible.

Further, an air intake hole and an air discharge hole are formed in a seat rubber interposed on a connecting surface between the idle speed control means for bypassing the intake air from the throttle body and the surge tank, and the air is supplied to the surge tank. The present invention aims to avoid the need to form the suction hole and the air discharge hole, and thereby to simplify the structure of the surge tank.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall configuration of the outboard motor, and FIGS. 2 and 3 show an embodiment of the intake device for the outboard motor according to the present invention. In FIG. 1, the outboard motor 1 is
An upper case 3 on which the engine 2 is mounted, and a drive shaft housing 5 connected below the upper case 3.
And a lower case 7 supporting the screw 6 while being connected to the lower portion of the drive shaft housing 5.

As shown in FIGS. 2 and 3, the intake system for the engine 2 mounted in the upper case 3 includes a throttle body 11 in which a throttle valve 10 is housed,
A surge tank 1 having an inlet manifold 13 connected to the throttle body 11 and a predetermined capacity to which air is supplied via the inlet manifold 13.
4 and a distribution passage 15 for distributing the air supplied through the surge tank 14 from the crank chamber 17 to each combustion side.
A distribution unit 15 having A to 15F, an injector 19 provided side by side with this distribution unit 15, a reed valve 18 arranged between the distribution unit 15 and the crank chamber 17, and intake air from the throttle body 11. And an idle speed control means 30 for bypassing.

As shown in FIG. 3, the surge tank 14 has a box-like shape extending vertically in the up-down direction, and the distribution passages 15A to 15A are provided therein.
A guide 20 for distributing air to 15F is provided. The guide 20 is formed in a spiral shape in the axial direction, and the upper and lower ends thereof are the surge tank 1
It is designed to be pivotally supported by 4. At this time, the guide 20
The shaft supporting portion is formed in the hole 14A for removing the core of the mold when the surge tank 14 is cast-molded. Therefore, no special processing is required to insert the guide 20 into the surge tank 14. It is like this.

Air supplied by the guide 20 into the surge tank 14 through the throttle body 11 and the inlet manifold 13 flows along the spiral of the guide 20 as shown by the arrow in FIG. Road 1
After being equally distributed to 5A to 15F, it is supplied into the crank chamber 17 via the reed valve 18.

The reed valve 18 has a tongue piece 18B for opening and closing the hole 18A and a stopper piece 18C for the tongue piece 18B.
The reed valve 18 shown in FIG.
A fuel reservoir 24 is formed at the lower position in FIG. The pool 24 is formed by the reed valve 18
A hole or notch 26 is provided in the partition wall 25 portion located on the lower side in the figure so as to communicate with the fuel flow passage 27 communicating with the crank chamber 17.

Therefore, when the outboard motor 1 shown in FIG. 1 is tilted up, that is, when the right side portion shown in FIG. 4 is located above or when idling, the fuel accumulated in the crank chamber 17 is discharged. Fuel is stored in the reservoir 24 via the notch 26 so that fuel is not suddenly supplied to the combustion side when the engine is driven or accelerated.

The idle speed control means 30 has a seat rubber 3 between the surge tank 14 and the surge tank 14.
It is attached through 1. This seat rubber 31
Is attached to the wall portion 14A that defines the surge tank 14 and the step portion 1
An air intake hole 31A that is inserted into a hole 14C formed through 4B and that communicates with the hole 11A that communicates with the throttle body 11, and the air intake hole 31A.
After being introduced into the idle speed control means 30 from A, an air discharge hole 31B for supplying air into the surge tank 14 is formed.
As a result, the amount of air during idling is bypassed from the throttle body 11 to the surge tank 14 and a predetermined flow rate adjustment is performed.

Therefore, according to the above-mentioned structure of the present invention, since the guide 20 is provided in the surge tank 14 and the guide 20 is formed in the spiral shape extending in the axial direction, the air can be supplied without providing the inlet manifold 13 largely. There is an effect that the distribution can be equalized as much as possible and the engine output can be maximized. In addition, the equal distribution of the air has an effect of eliminating the cause of the decrease in the engine output caused by the uneven air supply as in the related art.

The guide 20 is connected to the surge tank 14
As described above, there is an advantage that no special processing is required in the manufacturing process by utilizing the hole 14A for removing the core, as described above. In addition, since the guide 20 is supported in a manner to be vertically suspended in the surge tank 14, it has an additional effect of improving the rigidity of the surge tank 14.

Further, by forming the fuel reservoir 24 as shown in FIGS. 4 and 5, when the outboard motor 1 shown in FIG. 1 is tilted up or idling, the crank chamber 17 is provided. It is possible to store the accumulated fuel in the reservoir 24 through the notch 26, so that the fuel is not rapidly supplied to the combustion side during engine driving or acceleration, and the fuel concentration is relatively high. It is possible to prevent the smoke from becoming extremely thick, and to effectively prevent the generation of white smoke. The pool 24
The fuel accumulated in is gradually sucked up by the negative pressure during traveling due to the negative pressure and disappears, and it is not necessary to provide a check valve for circulating the accumulated fuel, so that the structure can be simplified. Further, the effect that the special pipe for circulating can be wiped out is added.

Further, since the air intake hole 31A and the air discharge hole 31B are formed in the seat rubber 31 interposed between the idle speed control means 30 and the surge tank 14, the shape of the surge tank 14 is simplified. There is an effect that you can. Therefore, it is expected to suppress the manufacturing cost of the entire intake device.

[0024]

Since the present invention is constructed as described above, it makes it possible to evenly supply intake air to the combustion side, thereby reducing the size of the intake manifold and maximizing engine performance. It is possible to expect that it can be demonstrated, and by providing the accumulated fuel in the crank chamber temporarily, it is possible to suppress sudden fuel intake such as when the engine is driven as much as possible and prevent the generation of white smoke, Furthermore, by providing a special shape for the seat rubber between the idle speed control means and the surge tank, it is possible to further simplify the structure of the surge tank. can do.

[Brief description of drawings]

FIG. 1 is an external configuration diagram of an entire outboard motor.

FIG. 2 is a plan view showing a schematic cross-section of an intake device according to the present invention.

FIG. 3 is a side sectional view of FIG.

FIG. 4 is a cross-sectional view for explaining a fuel reservoir in the embodiment.

5 is a view of FIG. 4 viewed from the direction of arrow A. FIG.

FIG. 6 is a sectional view showing a connecting portion between an idle speed control means and a surge tank in the embodiment.

FIG. 7 is a sectional view corresponding to FIG. 6 for explaining a conventional example.

[Explanation of symbols]

 1 Outboard Motor 11 Throttle Body 13 Inlet Manifold 14 Surge Tank 14A Surge Tank Forming Wall 18 Reed Valve 20 Guide 24 Fuel Pool 30 Idle Speed Control Means 31 Seat Rubber 31A Air Suction Hole 31B Air Discharge Hole

Claims (3)

[Claims] 1. A throttle body, and a surge tank communicating with the throttle body via an inlet manifold, wherein air introduced into the surge tank can be supplied to a plurality of combustion sides via a reed valve. The outboard motor intake device, wherein a guide for distributing air to each combustion side is provided in the surge tank. 2. The intake system for an outboard motor according to claim 1, further comprising a fuel reservoir formed below the reed valve for temporarily storing fuel supplied into the crank chamber. 3. An idle speed control means for bypassing the intake air from the throttle body to the surge tank is provided, and an air intake hole is formed in a seat rubber interposed between the idle speed control means and the surge tank. The air intake device for an outboard motor according to claim 1, wherein the sheet rubber is inserted into and held by a wall forming the surge tank.