JPH0466759A - Suction device of outboard motor - Google Patents

Abstract

PURPOSE:To make the distribution of intake gas even at the upper side and the lower side by providing an upper wall, and a lower wall furnishing a notch, at the inner hole of a gasket placed between the entrance of a suction maniford and a carburetter, and forming the inner hole of the gasket in the form longer sideways. CONSTITUTION:To an engine 2 for outboard motor in which two cylinders 3 are provided up and down, and a crankshaft vertically, crankcases 5 of the upper and the lower cylinders 3 are connected to a suction maniford 7 through lead valves 6 respectively. The entrance 8 of the suction maniford 7 is provided biased to the upper side, and a carburetter 10 is connected to the entrance 8 placing a gasket 9 between them. In this case, the inner hole of the gasket 9 is formed longer sideways, projecting an upper wall 12, and the lower wall furnishing a notch at the center, to the venturi 11 of the carburetter 10 and to the circular section of the entrance 8 of the maniford 7, and the passage is restricted thereby. As a result, the distribution of the fuel absorbed from the carburetter 10 to the upper and the lower crankcases 5 is made even, and the air-fuel ratio can be made constant.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an intake device for an outboard motor that improves the distribution of intake air.

[Conventional technology]

Outboard motors often use a two-cycle engine for power. In an outboard motor, the crankshaft is arranged vertically, and in the case of a two-cylinder motor, the cylinders are arranged vertically.

The crank chambers of the upper and lower cylinders are connected to the intake manifold via reed valves, and a carburetor is connected to the inlet of the intake manifold.The carburetor atomizes fuel into the intake air, creating negative pressure in the upper and lower crank chambers. At this time, the reed valve opens and intake air is sucked in. For example, JP-A-6020495
See Publication No. 4 and Japanese Utility Model Application No. 61-14764. Japanese Patent Publication No. 52-41813 is known for improving fuel distribution.

[Problem to be solved by the invention]

In a two-cycle engine with two cylinders arranged one above the other and with a vertical crankshaft, the carburetor installation depends on the height, left-right position, and position of the main nozzle tip of the carburetor itself in the upper and lower crank chambers. The distribution of intake air changes greatly. Also, when installing a slow type carburetor, the distribution to the upper and lower crank chambers changes depending on the position, resulting in higher or lower concentration. Furthermore, in the case of outboard motors, the engine compartment covered by the engine cover is narrow, and the location of the carburetor is restricted, and the location of the carburetor is also restricted by the throttle position and silencer position. , the intake air sucked into the upper and lower crank chambers via the intake manifold becomes unbalanced.
There is an inconvenience that one side is dark and the other is thin.

In view of this, the present invention provides an intake system for an outboard motor that can evenly distribute upper and lower intake air by deforming the inner hole of a gasket interposed between the intake manifold inlet and the carburetor. With the goal.

[Means to solve the problem]

In order to achieve the above object, the intake system for an outboard motor of the present invention connects the upper and lower crank chambers of a two-cylinder two-cycle engine, in which cylinders are arranged one above the other, to the intake manifold via a reed valve. The carburetor is connected to the inlet provided near the top by sandwiching a gasket, and a lower wall with a soil wall and a notch is provided in the inner hole of the gasket, and the circular cross section of the carburetor and intake manifold inlet is On the other hand, the inner hole of the gasket is formed into a horizontally elongated hole.

[For production]

At low speeds, fuel is supplied from the slow port located above the venturi in the carburetor. Normally, air flows easily to the upper crank chamber near the intake manifold inlet, but by blocking the earth wall installed in the gasket, the amount of air flowing to the upper crank chamber is reduced, and the intake air flowing to the upper and lower crank chambers is reduced. It can be made uniform.

At high speeds, the overall flow rate of intake air becomes faster and the flow of intake air becomes linear. Fuel is then supplied from the main nozzle that opens in the center of the venturi of the carburetor. Because of the upper wall of the gasket, which improves distribution at low speeds, the lower crank chamber tends to be darker than the crank chamber on the upper wall. This prevents this from occurring and evens out the distribution between the upper and lower crank chambers. Additionally, the notch provided in the lower wall can prevent fuel from accumulating below the venturi of the carburetor.

〔Example〕

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

When a two-cylinder two-cycle engine 2 is used to power the outboard motor 1, the two cylinders 3 are arranged one above the other, and the crankshaft is placed vertically. The engine 2 is placed inside the engine cover 4 above the outboard motor 1. The crank chambers 5 of the upper and lower cylinders 3 are connected to an intake manifold 7 via lid valves 6, respectively.

An inlet 8 of the intake manifold 7 is provided toward the upper side, and connects a carburetor 10 with a gasket 9 interposed therebetween. The venturi 11 of the carburetor 10 is inserted into the inner hole of the gasket 9.
With respect to the circular cross section of the inlet 8 of the intake manifold 7, an upper wall 12 and a lower wall 14 having a notch 13 in the center are protruded and formed into a horizontally elongated hole to restrict the passage. vaporizer 1
0, the main nozzle 15 is opened in the center of the venturi 11, and the slot system port 16 is opened above the venturi 11.

At low speeds, as shown in FIG. 3, fuel is supplied from the slow system port 16 on the upper side of the venturi 11, and the upper crank chamber 5 located nearby tends to become rich, but the upper wall 12 of the gasket 9 flows. bypass the upper and lower crank chambers 5.
Equalize the distribution of At high speeds, as shown in FIG. 4, fuel is supplied from the main nozzle 15 at the center of the venturi 11, and since the rotation is fast, the flow rate is also fast. At this time,
The upper wall 12 of the gasket 9 is bypassed so that the upper crank chamber becomes thinner, but the lower wall 14 of the lower side of the gasket 9
Since it is arranged so as to be even with the upper side, the distribution to the upper and lower crank chambers 5 is made uniform, and the air-fuel ratio is kept constant. or,
The notch 13 provided in the center of the lower wall 14 of the gasket 9 is
Fuel can be prevented from accumulating in the venturi 11.

〔Effect of the invention〕

As explained above, since this invention is configured as described above, the fuel flowing to the upper and lower crank chambers can be adjusted by the earthen wall and lower wall provided on the gasket sandwiched between the intake manifold inlet and the carburetor. , it is possible to equalize and stabilize the air-fuel ratio. This ensures stable operation at both high and low speeds,
The carburetor has a wider range of settings, resulting in stable operation even with thin overall settings, and reduced fuel consumption.

Additionally, a notch in the center of the bottom wall of the gasket prevents fuel pooling. Furthermore, since the punched hole inside the gasket can be changed, the adjustment is simple and can be implemented without increasing costs.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, Fig. 1 is a front view of the gasket, Fig. 2 is a longitudinal side view of the gasket, Fig. 3 is a longitudinal side view showing the situation at low speed, and Fig. 4 is a longitudinal side view of the gasket at high speed. Figure 5 is a partially cutaway side view of the engine, and Figure 6 is a side view of the entire outboard motor. 1... Outboard motor, 2... Engine, 3... Cylinder, 5...
・Crank chamber, 6... Reed valve, 7... Intake manifold, 8... Inlet, 9... Gasket, 10... Carburetor, ] 2... Upper wall, 13... Notch, 14 ...lower wall.

Claims (1)

[Claims] The upper and lower crank chambers of a two-cylinder, two-stroke engine with cylinders arranged one above the other are connected to the intake manifold via reed valves, and the inlet is placed near the top of the intake manifold.
The carburetor is connected with a gasket in between, and the inner hole of the gasket is provided with an upper wall and a lower wall with a notch, so that the inner hole of the gasket is horizontally long with respect to the circular cross section of the inlet of the carburetor and the intake manifold. An intake device for an outboard motor, characterized in that a hole is formed.