JPH0159427B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic fuel extraction device for a carburetor.

[Conventional technology]

In conventional small general-purpose gasoline engines equipped with a so-called float type carburetor, the engine is generally stopped electrically by pressing the stop button.
After the engine is stopped, most of the fuel in the float chamber remains in the float chamber without any particular removal.

There is a device for draining the fuel in the float chamber after the engine has stopped, as described in Japanese Utility Model Application No. 56-25047 or No. 55-83567.
All of these designs use negative pressure pumps or complex control valves or on-off valves as means for returning residual fuel in the float chamber to the fuel tank.

[Problem to be solved by the invention]

If the fuel in the float chamber is not drained, if the engine is left as is for a long period of time after the engine has stopped, the gasoline accumulated in the float chamber of the carburetor will deteriorate and the foreign substances generated will cause malfunction of the carburetor. There are problems such as failure to start the next time it is used.

Also, Utility Model Application No. 56-25047 and Utility Model Application No. 55-
The devices described in the 83567 publication all have problems such as complicated structures, high costs, and uncertain functions.

The present invention eliminates the above problems in the prior art and provides a simple and reliable device that automatically releases the fuel in the carburetor float chamber to empty the float chamber when the engine is stopped. It is intended to.

[Means to solve the problem]

A return oil passage connects the bottom of the float chamber of the carburetor and the upper air reservoir of the fuel tank, and a ventilation passage connects the upper air reservoir of the fuel tank and the intake passage of the carburetor.

A fuel tank provided between a fuel tank and a float chamber of a carburetor and a ventilation passage socket provided in an air passage are mechanically interlocked.

[Effect]

When the engine is operating, that is, when the fuel tank is open, the air passage port communicates between the upper air reservoir of the fuel tank and the atmosphere. When the engine is stopped, that is, when the fuel tank is closed, the air reservoir in the upper part of the fuel tank and the intake passage of the carburetor are communicated by the ventilation channel, and the negative pressure of the intake air from the engine, which continues to rotate, allows the oil to flow through the return oil channel. to suck up the fuel in the carburetor float chamber into the fuel tank. The fuel in the float chamber of the carburetor is drawn up into the fuel tank via the return oil path.

〔Example〕

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

FIG. 1 is a sectional view showing a fuel tank and a carburetor equipped with an embodiment of the device according to the present invention.

In the figure, 1 is a fuel tank, 2 is a tank cap, 3 is a ventilation passage connecting the upper air reservoir 1a of the fuel tank and the intake passage 11 of the carburetor 7, and 4 is a communication hole provided in the ventilation passage 3 and communicating with the atmosphere. 4a is a vent passage hole formed therein; 5 is a fuel supply passage connecting the fuel inlet passage 72 to the needle valve 71 of the carburetor and the bottom of the fuel tank 1; 6 is a fuel supply passage provided in the fuel supply passage; 8 is a float chamber, 9 is an air vent, 10
is a return pipe, that is, a return oil passage connecting the bottom of the float chamber 8 and the top of the fuel tank 1.

Reference numeral 12 is a link for interlocking the air passage socket 4 and the fuel socket 6. Note that an air breather, which was conventionally provided in the fuel tank, is not provided.

The operation in the case of the above configuration will be described.

Prior to stopping the engine, the ventilation passage socket 4 and the fuel socket 6 are linked via the link 12, and when the fuel socket 6 is closed, the communication hole 4a of the ventilation passage socket 4
is closed, and the ventilation passage 3 is opened, and the air pocket 1a of the fuel tank communicates with the intake passage to the engine through the ventilation passage 3. Therefore, the inside of the fuel tank becomes negative pressure due to the negative intake pressure of the engine, and the carburetor 7 The remaining fuel in the float chamber 8 is sucked up into the fuel tank 1 from the bottom of the float chamber 8 through a return pipe 10 connected to the top of the fuel tank 1. When the fuel tank is open, as shown in FIG. 1, the fuel tank 1 and the communication hole 4a to the atmosphere communicate with each other.

〔Effect of the invention〕

(1) When stopping the engine, the fuel supply is cut off by closing the fuel tank without stopping the engine electrically, and the engine can be stopped in a relatively short time (4 to 5 seconds in experiments).

(2) Since the fuel tank and the air passage socket are mechanically linked, when the fuel tank is closed, the upper air pocket of the fuel tank communicates with the intake passage via the air passage socket, and the intake air pressure of the engine is reduced. The upper air reservoir becomes negative pressure, and the fuel in the carburetor float chamber is drawn out toward the tank via the return oil path (return pipe).

In this way, when the engine is stopped, the fuel in the float chamber can be automatically emptied without using a pump or the like.

(3) The engine can be stopped and the fuel removed from the carburetor float chamber at the same time.

(4) Since no operating parts are required for fuel extraction after the engine is stopped, the configuration for achieving the same purpose is simple.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a fuel tank and carburetor equipped with an embodiment of the device according to the invention. 1... Fuel tank, 3... Ventilation passage, 4... Ventilation passage pot, 6... Fuel pot, 7... Carburetor, 8
...Float chamber, 10...Return pipe, 11
...Intake passage, 12...Link.

Claims (1)

[Claims] 1. In an engine having a float type carburetor to which fuel is supplied by gravity from a fuel tank via a fuel tank, a return oil passage connecting the bottom of the float chamber of the carburetor and the upper air reservoir of the fuel tank; a ventilation passage connecting an upper air reservoir of the fuel tank and an intake passage of the carburetor;
Furthermore, the air passage is mechanically linked to the fuel pot, so that when the fuel pot is opened, the upper air reservoir of the fuel tank is communicated with the atmosphere, and when the fuel pot is closed, the upper air reservoir of the fuel tank is connected to the atmosphere. An automatic fuel extraction device for a carburetor, characterized in that it is provided with a vent passage connected to an intake passage and sucking up fuel in the float chamber of the carburetor into a fuel tank through the return oil passage by the negative pressure of intake air of the engine.