JP2000045872A - Starting fuel supplying structure for carburetor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly start an engine by arranging a cup-like fuel reservoir surrounding a starting fuel bleed tube in a bottom part of the starting fuel bleed tube, and providing a gutter extended obliquely upward from the fuel reservoir to a lower end of an inflow valve. SOLUTION: In order to supply the fresh fuel inside a fuel tank to a starting fuel system, a cup-like fuel reservoir 29 covering a bottom part of a starting fuel bleed tube 27 is supported on a lower wall of a carburetor main body 14, and a gutter 31 extended obliquely upward from the fuel reservoir 29 to a lower end of an in flow valve 34 through a pair of floats 28 in front and behind is integrally provided. Fuel quantity to be supplied from the gutter 31 to the fuel reservoir 29 is set larger than the fuel quantity to be leaked through a through hole, and at the time of starting the engine, the fresh fuel having a low viscosity from a fuel tank 7 is stored in the fuel reservoir 29, and made to flow from the fuel reservoir 29 to an intake passage 13 through a starting fuel injection hole. With this structure, the engine can be smoothly started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting fuel supply structure for a carburetor that enhances the startability of an engine.

[0002]

2. Description of the Related Art When an engine is left for a long period of time, the fuel in a fuel storage tank of a carburetor is deteriorated, so that the startability of the engine is poor. In other words, when the operation of the engine is stopped for a long time, the fuel inside the fuel tank is vaporized, and most of the fuel vapor is discharged to the outside from the breather. And fuel with high viscosity will stay. Therefore, even if cranking is performed at the time of starting the engine, the fuel in the fuel storage tank is difficult to flow smoothly to the starting fuel system and the like, which is one of the causes of impairing the startability of the engine. .

[0003] In addition, when the engine is started, even if new fuel is supplied to the fuel storage tank, the fuel does not mix with the deteriorated fuel and accumulates on the upper side of the deteriorated fuel. Fuel is not drawn into the engine from the starting fuel passage via the intake passage, and consequently considerable time is spent starting the engine.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to supply a starting fuel for a carburetor so that fresh fuel in a fuel tank is always supplied to a starting fuel system when the engine is started. It is to provide a structure.

[0005]

In order to solve the above-mentioned problems, according to the present invention, a cup-shaped fuel reservoir surrounding the starting fuel bleed tube is disposed at the bottom of the starting fuel bleed tube, and the starting fuel bleed tube is disposed from the fuel reservoir. A gutter extending obliquely upward is provided at the lower end of the inflow valve.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a structure is adopted in which fuel newly supplied from a fuel tank to a fuel storage tank of a carburetor accumulates near a starting fuel bleed pipe. In other words, a small-capacity fuel reservoir is provided around the starting fuel bleed pipe, so that the fuel flowing from the fuel tank to the fuel storage tank is directly stored in the fuel reservoir at the same time as the operation of starting the engine. Therefore, at the same time when the engine is started, the fresh fuel accumulated in the fuel reservoir of the carburetor flows to the intake passage via the starting fuel bleed pipe, so that the engine is started smoothly.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A constant-vacuum sliding throttle valve type carburetor is a carburetor body 1
4 is supported by a valve shaft 4 on the outlet side of an intake passage 13 passing through the intake passage 4 in a lateral direction, and a cylindrical portion 9 is formed in the center portion of the intake passage 13 so as to cross the intake passage 13. 23 is supported so as to be able to move up and down. A cup-shaped cover 18 is connected to the upper end surface of the vaporizer body 14 together with the membrane 20 by a plurality of bolts.
The atmosphere chambers 15 are defined below 0, respectively. Atmospheric chamber 1
5 is communicated with the start end of the intake passage 13 via the passage 22. The annular seat plates 16 and 21 are superposed on the upper and lower surfaces of the membrane 20, and the upper ends of the sliding valves 23 are fitted to the seat plates 16 and 21 and then the upper edges of the sliding valves 23 are bent and joined. Is done. Cover 18
A spring 19 is interposed between the valve and the sliding throttle valve 23. Actually, the lower end of the spring 19 is in contact with the projection 23 a of the sliding throttle valve 23 and the spring seat 8. The upper end of the fuel adjustment needle valve 24 is inserted and supported in the bottom wall of the sliding throttle valve 23, and the spring 7 is interposed between the valve seat 8 and the retaining ring at the upper end of the fuel adjustment needle valve 24.

The fuel adjusting needle valve 2 is provided on the lower wall of the carburetor body 14.
4 is supported, and the lower end of the main fuel bleed tube 25 projects into the fuel chamber 30 a of the fuel storage tank 30. The fuel storage tank 30 is provided on the bottom surface 14 of the carburetor body 14.
a, and a plurality of bolts are screwed into the screw holes 42 of the carburetor body 14 and fastened. A fuel inlet chamber 12 is provided in a lower wall portion of the carburetor body 14, and an inlet valve 3 is provided in the fuel inlet chamber 12.
4 is supported so as to be able to move up and down. The lower end of the inflow valve 34 is provided with a receiving plate 32 of an arm 32 supported by a pin 33 on the carburetor body 14.
a. The tip (left end) of the forked arm 32 supports a pair of front and rear floats 28 via a mounting piece 32b.

The fuel in a fuel tank (not shown) is supplied to the fuel storage tank 3 through a fuel inlet chamber 12 and an inflow valve 34 by a fuel pump.
When it is filled to zero, the arm 32 is rotated clockwise about the pin 33 by the buoyancy acting on the float 28. The inflow valve 34 is pushed up by the arm 32, and the valve hole 12a is closed. The fuel in the fuel storage tank 30 is drawn into the intake passage 13 through the main fuel bleed pipe 25 and the main fuel injection hole 10 by the intake negative pressure in the intake passage 13. The low-speed fuel bleed pipe 6 and the starting fuel bleed pipe 27 project from the wall of the carburetor body 14 into the fuel storage tank 30. The upper end of the starting fuel bleed pipe 27 is communicated through the internal passage 5 of the carburetor body 14 to the fuel chamber accommodating the heating plug 3, and is further opened through the internal passage 5a and a known bi-starter to the intake passage 13. It is communicated with a fuel injection hole (not shown).

According to the present invention, in order to supply fresh fuel in the fuel tank to the starting fuel system (or a low-speed fuel system), a cup-shaped fuel reservoir 29 covering the bottom of the starting fuel bleed pipe 27 is provided with a carburetor. The main body 14 is supported by the lower wall. A gutter 31 extending diagonally upward from the fuel reservoir 29 and between the pair of front and rear floats 28 is integrally provided. The tip of the gutter 31 protrudes below the arm 32. Preferably, the fuel reservoir 29
A small through hole is provided at the lower end of the. The inside diameter of the through hole is set so that the amount of fuel flowing out of the through hole is smaller than the amount of fuel flowing into the fuel reservoir 29 from the gutter 31.

Next, the operation of the starting fuel supply structure for a carburetor according to the present invention will be described. When the starting operation of the engine is started, first, the fuel pump is driven, and the fuel in the fuel tank is supplied to the fuel storage tank 30 of the carburetor through the fuel inlet chamber 12 and the inflow valve 34. Most of the fresh fuel in the fuel tank is supplied to a small-capacity fuel reservoir 29 via a gutter 31. When the fuel is filled in the fuel tank 29, excess fuel overflows to the fuel storage tank 30. When the oil level in the fuel tank 30 reaches a predetermined level (a level lower than the fuel reservoir 29), the inflow valve 34
Closes. Even if the fuel does not reach the predetermined level, if the engine is started (cranking), the intake path 1
The intake negative pressure of 3 acts on the starting fuel bleed pipe 27 via the passage 5. Accordingly, the fuel in the fuel reservoir 29 is sucked into the intake passage 13 through the starting fuel bleed pipe 27, the passages 5 and 5a low-speed fuel injection holes, and mixed with air in the intake passage 13 and supplied to the engine. Is started smoothly.

When the fuel in the fuel tank 29 runs out, the fuel in the fuel storage tank 30 is supplied to the intake passage 13 through the low-speed fuel bleed pipe 6 and the low-speed fuel injection hole. Thus, even when the engine is started, the fuel is continuously supplied from the fuel tank to the fuel tank 29. When the engine is stopped, the fuel in the fuel tank 29 drops from the small through hole at the bottom into the fuel storage tank 30, Fuel reservoir 2
No fuel is stored in 9.

At the next start of the engine, there is no old fuel inside the fuel tank 29, and fresh fuel in the fuel tank is supplied to the fuel tank 29 at the same time as the operation of starting the engine. If the amount of fuel supplied from the gutter 31 to the fuel tank 29 is larger than the amount of fuel leaking from the through hole, fresh fuel having a low viscosity from the fuel tank is stored in the fuel tank 29 when the engine is started. From the starting fuel injection hole to the intake passage 13, so that the engine can be smoothly started.

In the embodiment shown in FIG. 3, a cylinder 67 projecting from the lower wall of the carburetor body 14 into the fuel storage tank 30 is provided.
Upper end 2 of starting fuel bleed tube 27 having a number of through holes
7a is screwed and supported, and a jet 27b is fitted and supported on the lower end of the starting fuel bleed pipe 27. Starting fuel bleed pipe 2
An elongated cup-shaped fuel reservoir 29 having a through hole 29a at the bottom is connected to the lower end of the fuel cell 7. Specifically, a retaining ring 66 is locked in an annular groove 65 provided in the starting fuel bleed pipe 27,
The fuel reservoir 29 is externally fitted to the retaining ring 66, and the plurality of bent pieces 72 formed on the upper edge of the fuel reservoir 29 are engaged with the retaining ring 66 so as not to fall off. However, the upper edge of the fuel reservoir 29 is bent inward, and the bent portion is connected to the starting fuel bleed pipe 2.
7 may be firmly fitted to the lower end.

In order to supply fresh fuel from the inflow valve 34 to the fuel reservoir 29, the fuel tank 29 is cut and raised from the upper edge thereof.
3 is formed outwardly to form a gutter 31 that projects obliquely upward. If the gutter 31 is short, another gutter is connected and the tip of the gutter 31 is projected below the inflow valve 34. The upper end of the starting fuel bleed pipe 27 projects outside through the internal passage 5 of the carburetor body 14. The end of the passage 5 is closed by a stopper, and an intermediate portion of the passage 5 is connected to the starting fuel injection hole via a check valve.

[0016]

As described above, according to the present invention, a cup-shaped fuel reservoir surrounding the starting fuel bleed tube is disposed at the bottom of the starting fuel bleed tube, and the fuel reservoir is obliquely upwardly moved from the fuel reservoir to the lower end of the inflow valve. Since the engine is provided with an extended gutter, even after the engine has been left for a long period of time, prior to starting the engine, fresh fuel in the fuel tank is introduced into the fuel reservoir via the inflow valve and the gutter, and fresh fuel is supplied from the fuel reservoir. Fuel is supplied to the starting fuel system via the starting fuel bleed tube, and a smooth start of the engine is achieved.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a carburetor provided with a starting fuel supply structure according to the present invention.

FIG. 2 is a plan sectional view of the vaporizer.

FIG. 3 is a front sectional view showing a specific structure of a starting fuel bleed pipe of the vaporizer.

[Explanation of symbols]

2: Chiyoke valve 3: Heating tap 4: Valve shaft 5: Passage 5
a: passage 6: low-speed fuel bleed pipe 7: spring 8: spring seat 9: cylindrical portion 10: main fuel injection hole 12: fuel inlet chamber 12a: valve hole 13: intake path 14: body 14
a: Bottom 15: Atmospheric chamber 16: Seat plate 17: Negative pressure chamber
18: cover 19: spring 20: membrane 21: seat plate 2
2: Passage 23: Sliding throttle valve 23a: Projection piece 24: Fuel adjusting needle valve 25: Main fuel bleed pipe 27: Starting fuel bleed pipe
28: float 29: fuel reservoir 29a: through hole 30: fuel storage tank 31: gutter 32: arm 32a: receiving plate 32b:
Mounting piece 33: Pin 34: Inflow valve 41: Pillar 42:
Screw hole 65: Annular groove 66: Retaining ring 72: Cut and raised piece

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Teruhiko Tonai 2-3-3 Shiba-koen, Minato-ku, Tokyo F-term in Walbro, Japan 3G006 AH00

Claims (2)

[Claims] 1. A starting fuel bleed pipe is provided with a cup-shaped fuel reservoir surrounding the starting fuel bleed pipe at the bottom thereof, and a gutter extending obliquely upward from the fuel reservoir to the lower end of the inflow valve. The supply structure of the starting fuel for the carburetor. 2. The fuel tank according to claim 1, wherein a through hole is provided at a bottom portion of the fuel reservoir, and an amount of fuel flowing out of the through hole of the fuel reservoir is smaller than an amount of fuel flowing into the fuel reservoir through the gutter. A fuel supply structure for starting a carburetor according to Claim 1.