JPH10205391A - Overflow device for carburetor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate engine starting even after the stop of a long time by protruding the lower end of an overflow pipe opened upward more than the normal time liquid surface of a carburetor float room in a cup and discharging fuel flowing out of the overflow pipe to overflow from the cup. SOLUTION: A cup 14 is inserted into an overflow nipple 15 fitted in the bottom part of the container member 4 of a carburetor 1, and the lower part of an overflow pipe 13 extended from the bottom part of the container member 4 upward more than the normal time liquid surface of a float room 4a is extended near the bottom surface of the cup 14. Then, fuel flowing down from the overflow pipe 13 because of the increase of the liquid surface of the float room 4a is guided from the cup 14 to the overflow nipple 15 and then discharged from a hose. Thus, the evaporation of fuel from the float room 4a during an engine stop is prevented, fuel steam is condensed in liquid fuel in the cup and thus the liquid fuel is held in the cup 14 for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carburetor overflow device, and more particularly to a carburetor overflow device suitable for an engine having no priming device.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a vaporizer 1 using a conventional overflow device. Vaporizer body 2 shown in this figure
A container member 4 is fastened to a lower portion of the container to form a float chamber 4a. Further, the carburetor body 2 is formed with a cylindrical portion 2a extending toward the air passage 3 and the float chamber.

The sliding valve 5 is fitted into a vertical guide hole provided in the carburetor body 2 so as to be able to protrude into the air passage 3. That is, the slide valve 5 is urged downward by the compression coil spring 12, and a wire (not shown) attached to the wire attachment portion 5a is connected to the accelerator. When the accelerator operation is loosened, the sliding valve 5 is lowered so as to close the air passage 3, and when the accelerator is operated, the sliding valve 5 is pulled by the wire and rises. In this way, the access of the sliding valve 5 to the air passage 3 can be controlled by the accelerator. That is, the amount of air passing through the air passage 3 can be adjusted by the accelerator.

[0004] A float 9 arranged in the float chamber 4a floats on the fuel, and opens and closes a float valve (not shown) according to the level of the liquid level. That is, when the liquid level is high, the float 9 closes the float valve connected to the fuel supply pipe, and when the liquid level is low, the float 9 opens the float valve to keep the liquid level of the float chamber 4a constant.

A needle jet 8 is inserted and fixed in a cylindrical portion 2a extending from the vaporizer main body 2 toward the float chamber 4a.
Is installed. The needle jet 8 is provided with holes 8a on its side surface. Main jet 10
Is formed in a ring shape to have a squeezing action,
A predetermined amount of fuel flows according to the pressure difference between the inlet and the outlet.

[0006] The suction passage 7 is formed so as to communicate the upstream side of the air passage 3 with a gap outside the needle jet 8. The jet needle 6 has several grooves formed therein. An E-ring 6a is fitted in any of the grooves, and the jet needle 6 is attached to the slide valve 5 via the E-ring 6a. The jet needle 6 attached to the lower portion of the sliding valve 5 in this manner
Penetrates into the needle jet 8 through the air passage 3.

As the jet needle 6 moves up and down, the gap between the tapered end of the jet needle 6 and the needle jet 8 increases or decreases. The air passage 3 of the carburetor 1 configured as described above is connected to the intake manifold of the engine.

The idle adjusting screw 11 is screwed with the carburetor body 2 so as to protrude toward the moving path of the sliding valve 5, and has a tapered tip. By adjusting the position of the idle adjustment screw 11, the maximum throttle amount of the air passage 4 of the sliding valve 5 is set. That is, the idle position of the sliding valve 5 is adjusted. The upper space in the float chamber 4a communicates with the atmosphere by an air vent 2b provided in the vaporizer main body 2.

An overflow pipe 13 is fixed from the bottom of the container member 4 to an opening above the liquid level of the float chamber 4a in a normal state. A fuel discharge nipple 16 is fixed to the bottom of the container member 4 so as to be connected to the lower end of the overflow pipe 13, and fuel exceeding the normal liquid level of the float chamber is discharged from a hose fixed to the fuel discharge nipple 16. Is done. With such an overflow device, the liquid level in the float chamber becomes abnormally high due to a malfunction of the float valve or the like, thereby preventing the fuel from overflowing into the cylinder of the engine and damaging the cylinder.

Next, the operation of the vaporizer 1 will be described. By operating the accelerator, the sliding valve 5 can be moved up and down to adjust the amount of air flowing through the air passage 3. The gap between the jet needle 6 and the needle jet 8 which moves up and down integrally with the slide valve 5 increases and decreases, and changes the amount of fuel passing through the gap.

In this manner, the amount of air-fuel mixture is controlled while maintaining a predetermined relationship between the amount of air and the amount of fuel supplied to the cylinder of the engine through the air passage 3. The ratio between the amount of air supplied to the engine and the fuel can be set by selecting the groove of the jet needle 6 into which the E-ring 6b is fitted.

A manual cock or an automatic cock is provided in the fuel passage for supplying fuel from the fuel tank to the carburetor. The automatic cock is opened by the negative pressure generated when the engine rotates. The manual cock is manually closed after the engine stops.

[0013]

In the carburetor provided with the above-mentioned conventional overflow device, when the engine is stopped for a long period of time, the fuel in the float chamber evaporates and the liquid level drops. Since the evaporated fuel is heavier than air, the amount of fuel lost by diffusion from the air vent 2b is small, but a large amount of fuel vapor heavier than air is lost from the overflow pipe 13 due to the siphon phenomenon.

In such a state, the fuel level of the float chamber has dropped and the fuel has lost a highly volatile component, making it difficult to start the engine. If the priming device is provided, the liquid level in the float chamber can be raised, but the fuel has low volatility and the starting performance of the engine is not improved much. Recently, many priming devices have been abolished to reduce costs. As described above, according to the carburetor provided with the conventional overflow device, there is a problem that it becomes difficult to start the engine when the engine is stopped for a long period of time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to provide a carburetor overflow device that can easily start an engine even when the engine is stopped for a long time. That is.

[0016]

In the vaporizer overflow device of the present invention, the lower end of the overflow pipe, which opens above the liquid level in the normal state of the vaporizer floating chamber, enters the cup and flows out of the overflow pipe. The fuel is configured to overflow from the cup and be discharged.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A vaporizer using an overflow device according to an embodiment of the present invention will be described with reference to FIGS. Members of the carburetor 1 shown in FIG. 1 that correspond to the members of the carburetor 1 shown in FIG. 4 are denoted by the same reference numerals, and descriptions of those members will be omitted.

The upper portion of the overflow pipe 13 fixed to the bottom of the container member 4 shown in FIG. 1 extends above the normal liquid level of the floating chamber 4a. An overflow nipple 15 is fitted inside the cylindrical portion 4b provided in the container member 4. A bottomed cylindrical cup 14 also shown in detail in FIGS. 2 and 3 is inserted into the overflow nipple 15. The lower part of the overflow pipe 13 enters the cup 14 and extends near the bottom of the cup 14.

The fuel level in the float chamber becomes abnormally high, and the fuel which has flowed down from the overflow pipe 13 enters the overflow nipple 15 from the cutout portion 14a through the cup 14, and is discharged from the hose fixed to the overflow nipple 15.

When the engine is stopped, fuel is not supplied to the float chamber 4a, but fuel evaporated from the float chamber 4a
4 is prevented from being lost by the siphon phenomenon by being sealed by the liquid fuel accumulated in the overflow pipe 13. The surface of the liquid fuel outside the overflow pipe 13 of the cup 14 is narrow, and the amount of evaporation of the fuel is small. Also,
The vapor of the fuel evaporated from the float chamber descends from the overflow pipe 13 and condenses in the liquid fuel in the cup 14, and the liquid fuel is kept in the cup 14 for a long period of time.

Since the fuel vapor evaporated in the float chamber 4a is heavier than air, the amount of the fuel vapor lost by diffusion from the narrow air vent 2b is small. Therefore, even if the engine is stopped for a long time, the fuel in the float chamber does not decrease and the engine can be started easily.

[0022]

As described above, according to the carburetor overflow device of the present invention, even if the engine is stopped for a long period of time, the fuel in the float chamber is prevented from evaporating and it is difficult to start the engine. Never be. Further, since the fuel is not discharged into the atmosphere, air pollution is prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a vaporizer to which an overflow device according to the present invention is applied.

FIG. 2 is a partial cross-sectional view showing the overflow device.

FIG. 3 is an exploded perspective view showing a part of the overflow device.

FIG. 4 is a cross-sectional view showing a vaporizer provided with a conventional overflow device.

[Explanation of symbols]

Reference Signs List 1 vaporizer 2 vaporizer main body, 2a cylindrical portion, 2b air vent 3 air passage 4 container member, 4a float chamber, 4b cylindrical portion 5 sliding valve, 5a wire mounting portion 6 jet needle, 6a E-ring 7 suction path 8 Needle jet, 8a hole 9 Float 10 Main jet 11 Idle adjusting screw 12 Compression coil spring 13 Overflow pipe 14 Cup, 14a Notch 15 Overflow nipple 16 Fuel discharge nipple

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[Procedure amendment]

[Submission date] May 23, 1997

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

Claims (1)

[Claims] 1. A lower end of an overflow pipe opening above a normal liquid level of a vaporizer float chamber is inserted into a cup,
An overflow device for a carburetor, wherein the fuel flowing out of the overflow pipe overflows from the cup and is discharged.