JPH0544534Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to an automatic fuel drain device for a gasoline engine that automatically collects fuel in the carburetor into a fuel tank when the engine is not operating. .

[Conventional technology]

Conventionally, there has been known an automatic fuel drain device for a carburetor that automatically returns the fuel in the carburetor to the fuel tank simply by operating a knob when the gasoline engine is out of operation to prevent clogging of the main jet of the fuel system. ing.

In this automatic fuel drain device for a carburetor, two pipes, a fuel supply pipe and a drain pipe, are connected to the carburetor. When the engine is running, when the fuel tank of the fuel supply pipe is opened, fuel is supplied from the fuel tank to the carburetor, and at the same time. A drain/breather switching socket linked to the fuel tank closes the drain pipe of the carburetor and connects the breather pipe of the fuel tank to the breather, thereby supplying fuel and allowing the fuel tank to breathe.

When the fuel cap is closed after the engine has stopped, the fuel supply from the fuel tank to the carburetor is cut off, and the fuel cap also switches between the drain and the breather.The cap connects the carburetor's drain pipe to the fuel tank's breather pipe. let Therefore, after the engine is stopped, the fuel in the carburetor is automatically recovered into the fuel tank through the carburetor's drain pipe and the fuel tank's breather pipe due to the negative pressure inside the fuel tank that is generated due to the temperature drop in the fuel tank. Ru.

[Problems to be solved by the invention] As mentioned above, the conventional automatic fuel drain device for a carburetor has two pipes: a fuel supply pipe and a drain pipe.
There was a problem in that the structure was complicated because it required a fuel tank, a switch for switching between the drain and the breather, and an interlocking mechanism for both the sockets.

[Means for solving problems]

The purpose of the present invention is to simplify the configuration of the conventional automatic fuel drain device for a carburetor. At the same time, the breather pipe of the fuel tank is opened to the breather, and when the engine is not operating, the breather pipe is closed and the fuel inside the carburetor is recovered to the fuel tank by the negative pressure generated in the fuel tank. In the automatic drain device for a carburetor, a fuel supply/drain pipe is connected to the bottom of the float chamber of the carburetor, and the fuel is supplied to the opening of the fuel supply/drain pipe in the float chamber in conjunction with the rising and sinking of the float. A float valve is provided to supply and cut off fuel from the supply/drain pipe to the float chamber, and a check valve opens to the fuel supply/drain pipe when the internal pressure of the fuel tank drops below the internal pressure of the float chamber. During operation, fuel is supplied to the float chamber from the fuel supply/drain pipe through the float valve, and when the engine is not operating, the negative pressure generated in the fuel tank causes the fuel in the float chamber to be supplied to the float chamber through the float valve or check valve. The feature is that the drain pipe is reversed and the fuel is collected in the fuel tank.

[Effect]

With the above configuration, the pipe line connected to the carburetor is a single fuel supply pipe that also serves as a drain pipe.
Moreover, the interlocking mechanism of two cocks is not required.

〔Example〕

The present invention will be described in detail below based on illustrated embodiments.

Figure 1 is a longitudinal sectional view of the carburetor of the device of the present invention.
2 and 3 are configuration diagrams of the fuel circuit of the device of the present invention, with FIG. 2 showing the fuel circuit when the engine is operating, and FIG. 3 showing the fuel circuit when the engine is not operating.

This automatic fuel drain device 1 for a carburetor has a fuel supply/drain pipe 4 connected to the bottom of a float chamber 3 of a carburetor 2.
At the opening 5 in the float chamber 3, there is provided a float valve 7, which is a needle valve or the like, for supplying and shutting off fuel from the fuel supply/drain pipe 4 to the float chamber 3 in conjunction with the floating and sinking of the float 6, and a fuel tank. A check valve 8 is provided which opens toward the fuel supply/drain pipe 4 when the internal pressure of the float chamber 10 becomes lower than the internal pressure of the float chamber 3.

The fuel supply/drain pipe 4 is connected to one connection port of the operating socket 9 which is a four-way valve.
The other connection ports are connected to a fuel supply pipe 11 connected to the bottom surface of the fuel tank 10, a breather/drain pipe 12 connected to the top surface of the fuel tank 10, and a breather 13, respectively.

In the configuration described above, when operating the engine,
When the operating knob 9 is operated to the position shown in Fig. 2,
At the same time that the fuel supply pipe 11 on the fuel tank 10 side and the fuel supply/drain pipe 4 on the carburetor 2 side are opened, the breather/drain pipe 12 and breather 13 of the fuel tank 10 are opened, and the fuel is transferred to the fuel supply pipe 1.
1. Through the fuel supply/drain pipe 4, float valve 7
is supplied into the float chamber 3 from. Float chamber 3
When the fuel level within rises and reaches a predetermined level, the float valve 7 is closed in conjunction with the floating of the float 6, stopping the inflow of fuel. Fuel tank 10 due to fuel consumption
Air intake as the liquid level of the fuel tank 10 decreases and gas exhaust as the temperature of the fuel tank 10 increases are carried out by the breather 13 which is in communication with the breather/drain pipe 12 of the fuel tank 10.

When the engine is stopped and the operating knob 9 is moved to the position shown in FIG. 3, the fuel supply pipe 11 on the fuel tank 10 side and the fuel supply/drain pipe 4 on the carburetor 2 side
Communication between the breather/drain pipe 12 and the breather 13 is cut off, and at the same time, the fuel supply/drain pipe 4 on the carburetor 2 side is communicated with the breather/drain pipe 12 of the fuel tank 10. When the temperature of the fuel tank 10, which has increased during engine operation, decreases over time after the engine is stopped, negative pressure is generated within the fuel tank 10. At this time, if the float chamber 3 is not filled with fuel and the float valve 7 is open, the fuel in the float chamber 3 will flow from the float valve 7 to the fuel tank 10 through the fuel supply/drain pipe 4 and the breather/drain pipe 12. be sucked back into.

If the float chamber 3 is full of fuel and the float valve 7 is closed, the negative pressure in the fuel tank 10, which is lower than the internal pressure of the float chamber 3, first causes the check valve 8 to move toward the fuel supply/drain pipe 4. Open, fuel flows through check valve 8
Then, as the fuel level in the float chamber 3 decreases, the float valve 7 opens, and after the internal pressures of the float chamber 3 and the fuel tank 10 become equal, the check valve 8 closes, and the fuel flows through the float valve 7. It is sucked back into the fuel tank 10.

FIG. 4 is a vertical sectional view of an automatic breather device that functions as a normal breather that allows intake and exhaust when the engine is running, and as a one-way breather that allows exhaust but blocks intake air when the engine is stopped; The figure is a configuration diagram of a fuel circuit of an automatic fuel drain device for a carburetor incorporating this automatic breather device. In this automatic breather device 15, a spherical elastic valve body 17 made of rubber or the like is inserted into a small chamber 16 whose bottom surface has a concave spherical shape, and the center of the bottom surface of the small chamber 16 communicates with a breather pipe 19 of a fuel tank 18. An opening 20 is formed, and a normal breather 2 is formed on the top surface.
1 is provided. This automatic breather device 15
is attached to the engine 22 via a stay 23. In the figure, 24 is a general carburetor, 25 is a fuel supply/drain pipe connecting the carburetor 24 and the fuel tank 18, 26 is a general fuel tank interposed in the fuel supply/drain pipe 25, and 27 is a fuel tank 2.
This is a check valve that is interposed in a pipe that bypasses the fuel supply/drain pipe 25 on the fuel tank 18 side of No. 6 and the carburetor 24 side, and opens only on the fuel tank 18 side.

In the configuration described above, when the fuel tank 26 is opened and the engine 22 is started, fuel is supplied from the fuel tank 18 to the carburetor 24 and the engine 22 is operated, and the automatic breather device 15 is activated by the vibration of the engine 22 and the operation of the aircraft. The spherical elastic valve body 17 bounces around inside the small chamber 16, and the opening 20 inside the small chamber 16 is opened, so that the fuel tank 18 and the breather 21 communicate with each other, and intake and exhaust from the fuel tank 18 are performed.

When the engine 22 is stopped and the fuel tank 26 is closed, and the vibrations of the engine 22 and the aircraft body disappear, the spherical elastic valve body 17 in the small chamber 16 comes to rest in the opening 20 of the small chamber 16 and closes it. Therefore, when the temperature of the fuel tank 18 decreases after the engine is stopped, a negative pressure is generated in the closed fuel tank 18, and the fuel in the carburetor 24 opens the check valve 27 and flows back through the fuel supply/drain pipe 25 to become a fuel source. It is sucked back into the tank 18. When the temperature of the fuel tank 18 rises due to sunlight etc. and the internal pressure becomes high, the spherical elastic valve body 17 is pushed up and the air is exhausted from the breather 21, and the fuel tank 18
This prevents the internal pressure from increasing.

That is, the conventional automatic fuel drain device for a carburetor requires a fuel tank, a switch for switching between the drain and the breather, and an interlocking mechanism thereof, and the switch for switching between the drain and the breather is switched to the breather when the engine is running. However, by applying this automatic breather device, the valve mechanism can be changed to a normal valve mechanism. It requires a simple combination of a fuel tank and a check valve, and since the drain pipe and breather pipe are separated, there is no problem with conventional devices in which fuel remaining in the breather pipe leaks outside during engine operation.
Further, the spherical elastic valve body that only allows exhaust air causes the fuel tank to have a negative pressure, but not a positive pressure, so that the carburetor can reliably recover fuel.

[Effect of idea]

As mentioned above, the present invention opens the fuel supply line of the fuel tank to the carburetor and opens the breather line of the fuel tank to the breather when the engine is operating, and closes the breather line when the engine is not operating. , in an automatic drain device for a carburetor, which collects fuel in the carburetor into the fuel tank by the negative pressure generated in the fuel tank, a fuel supply/drain pipe is connected to the bottom of the float chamber of the carburetor; A float valve is provided at the opening of the fuel supply/drain pipe in the float chamber to supply or cut off fuel from the fuel supply/drain pipe to the float chamber in conjunction with the floating of the float. A check valve is installed that opens to the fuel supply/drain pipe when the pressure drops below the internal pressure.When the engine is running, fuel is supplied from the fuel supply/drain pipe to the float chamber through the float valve, and when the engine is not operating, fuel is generated in the fuel tank. The negative pressure generated in the float chamber causes the fuel in the float chamber to flow backward through the fuel supply/drain pipe through the float valve or check valve and is recovered into the fuel tank.
Two pipes, a fuel supply pipe and a drain pipe, are connected to the carburetor, and a single fuel supply pipe that also serves as the drain pipe requires a fuel socket, a switching socket between the drain and the breather, and an interlocking mechanism. This eliminates the need for a plurality of interlocking mechanisms, resulting in an extremely simplified configuration.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, FIG. 1 is a vertical sectional view of the carburetor of the device of the present invention, and FIG.
3 and 3 are configuration diagrams of the fuel circuit of the device of the present invention, with FIG. 2 showing the fuel circuit when the engine is operating, and FIG. 3 showing the fuel circuit when the engine is not operating. FIG. 4 is a longitudinal sectional view of the automatic breather device, and FIG. 5 is a configuration diagram of a fuel circuit in which the automatic breather device is incorporated into an automatic fuel drain device of a carburetor. DESCRIPTION OF SYMBOLS 1... Automatic fuel drain device, 2... Carburetor, 3... Float chamber, 4... Fuel supply/drain pipe, 5... Float chamber opening of fuel supply/drain pipe, 6... Float, 7... Float valve, 8...
... Check valve, 9 ... Operation control, 10 ... Fuel tank, 11 ... Fuel supply pipe, 12 ... Breather/drain pipe, 13 ... Breather.

Claims (1)

[Scope of utility model registration request] When the engine is operating, the fuel supply line of the fuel tank is opened to the carburetor, and the breather line of the fuel tank is opened to the breather, and when the engine is not operating, the breather line is closed,
In an automatic carburetor drain device that collects fuel in the carburetor into the fuel tank using negative pressure generated in the fuel tank, a fuel supply/drain pipe is connected to the bottom of the float chamber of the carburetor, and a fuel supply/drain pipe is connected to the bottom of the float chamber of the carburetor. supplying fuel from the fuel supply/drain pipe to the float chamber in conjunction with the floating and sinking of the float at the opening of the fuel supply/drain pipe;
It is equipped with a float valve that shuts off and a check valve that opens to the fuel supply/drain pipe when the internal pressure of the fuel tank drops below the internal pressure of the float chamber.When the engine is running, fuel is supplied from the fuel supply/drain pipe through the float valve. The fuel is supplied to the float chamber, and when the engine is not operating, the negative pressure generated in the fuel tank causes the fuel in the float chamber to flow back through the fuel supply/drain pipe through the float valve or check valve, and is recovered into the fuel tank. An automatic fuel drain device for a carburetor, which is characterized by: