JP2002039015A - Piston type throttle valve carburettor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mix fuel with intaken air by stopping the fuel creeping up from a high speed fuel nozzle hole along a fuel adjusting needle valve by means of an annular groove, and then splashing the fuel into an intake passage by intake air flow. SOLUTION: A cover 12 is connected to an upper end wall of a carburetor body 40 sandwiching a membrane 15 so as to define a negative pressure chamber 14 above the membrane 15 and an atmospheric chamber 18 below the membrane 15, respectively. A piston type throttle valve 24 is inserted into a cylinder 20 arranged so as to be perpendicular to an intake passage 30 of the carburetor body 40 and an upper end of the piston type throttle valve 24 is connected to the membrane 15. A passage 36 for introducing intake negative pressure is formed on a bottom wall of the piston type throttle valve 24 so as to lift the piston type throttle valve 24 according to the intake negative pressure acting against the force of a spring 13. A fuel adjustment needle valve 29 projecting from the bottom wall of the piston type throttle valve 24 is inserted into a fuel supply is inserted into a fuel supply pipe 6 elongating from a fuel reservoir 32 positioned at a lower portion of the carburetor body 40 toward the intake passage 30. The fuel adjustment needle valve 29 is provided with annular grooves 41, 42 which are exposed to the intake passage 30 in a state of a medium opening of the piston type throttle valve 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston type throttle for preventing fuel from creeping up along a fuel adjusting needle valve for adjusting the opening of a high-speed fuel injection hole in an opening range intermediate to the piston type throttle valve. The present invention relates to a valve type vaporizer.

[0002]

2. Description of the Related Art Since a conventional fuel adjusting needle valve has a cylindrical shape without irregularities, fuel sucked from a high-speed fuel injection hole crawls up the back surface of the fuel adjusting needle valve, and the back surface of the fuel adjusting needle valve. From the air into a belt-like or film-like shape, flows into the intake passage, and is sucked into the engine. For this reason, the atomization of the fuel is poor, and there have been problems with the responsiveness of the engine and the acceleration performance immediately after starting at low temperatures.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to suppress the fuel from creeping up from a high-speed fuel injection hole along a fuel adjustment needle valve, and to prevent the fuel adhering to the fuel adjustment needle valve from being taken in. The present invention is to provide a piston type throttle valve type carburetor which is scattered to an intake path by the flow of air and mixes with intake air.

[0004]

In order to solve the above-mentioned problems, according to the structure of the present invention, a lid is connected to an upper end wall of a vaporizer main body with a film interposed therebetween, a negative pressure chamber is provided above the film, and a negative pressure chamber is provided below the film. The upper end of a cup-shaped piston-type throttle valve fitted to a cylinder perpendicular to the intake path of the carburetor body so as to be able to move up and down is connected to the membrane, and the bottom wall of the piston-type throttle valve is formed. Provide a passage to take in the intake negative pressure, so that the piston type throttle valve rises according to the strength of the intake negative pressure against the force of the spring,
The fuel adjustment needle valve protruding from the bottom wall of the piston type throttle valve,
In a piston type throttle valve type carburetor fitted to a fuel supply pipe extending from a fuel storage tank at a lower portion of a carburetor body to an intake path, the fuel adjusting needle valve is exposed to the intake path at a middle opening degree or more of the piston type throttle valve. An annular groove is provided.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel adjusting needle valve for adjusting the opening of a high-speed fuel injection hole in an opening range in the middle of a piston type throttle valve is provided with an annular groove for preventing fuel from climbing up.
The fuel accumulates in the annular groove, and the fuel immediately accumulated in the annular groove is blown off by the flow of the intake air, atomized, and supplied to the engine, so that the responsiveness and acceleration of the engine are improved.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a piston type throttle valve type carburetor according to the present invention comprises
A cylinder 20 orthogonal to the intake passage 30 is formed on the upper side of the cylinder.
Are fitted so as to be able to move up and down. The dish-shaped lid 12 is connected to the upper end of the vaporizer main body 40 with the periphery of the membrane 15 interposed therebetween.
A negative pressure chamber 14 is defined on the upper side, and an atmosphere chamber 18 is defined on the lower side. The atmosphere chamber 18 communicates with the inlet side of the intake passage 30 via the passage 19. A pair of upper and lower annular holding plates 16 and 17 are superimposed on the membrane 15, and a piston type throttle valve 24 penetrating the holding plates 16 and 17 is joined by bending the upper end edge.

A butterfly type throttle valve 21 is rotatably supported by a valve shaft 22 downstream of the piston type throttle valve 24 in the intake path 30. Near the closed position of the throttle valve 21, a low-speed fuel injection hole 23 is provided. A fuel storage tank 32 is connected to the bottom of the carburetor body 40, and an arm 34 extending rightward from a horseshoe-shaped float 31 housed inside the fuel storage tank 32 is tiltably supported by a support shaft 35. The arm 34 is locked at the lower end of the inflow valve 9, and opens and closes the inflow valve 9 housed in the valve housing 8. The valve housing 8 is fitted into a cylindrical portion communicating with the fuel inlet 7.

A cylindrical portion 4 extending from the fuel storage tank 32 to the intake passage 30 is formed on a lower wall portion of the carburetor body 40.
Is fitted with a fuel supply pipe 6. The upper end of the fuel supply pipe 6 slightly projects into the intake path 30 to form the high-speed fuel injection hole 2.
A fuel adjusting needle valve 29 protruding downward from the piston type throttle valve 24 is inserted into the fuel supply pipe 6, and a fuel jet 33 is fitted and supported at a lower end of the fuel supply pipe 6. Further, a fuel supply pipe 3 is fitted and supported on a cylindrical portion 5 disposed substantially in parallel with the cylindrical portion 4 on a lower wall portion of the carburetor main body 40, and an upper end of the fuel supply pipe 3 is connected to a fuel passage 26 through a fuel passage 26. It is communicated with the injection hole 23. The upper and lower ends of the fuel supply pipes 6 and 3 are fitted and supported by the cylindrical parts 4 and 5, respectively, and the intermediate part is formed with an annular gap between the cylindrical parts 4 and 5 so that the fuel can be emulsified. Each fuel supply pipe 6, 3 is provided with a large number of lateral through holes.

As shown in FIG. 2, the upper end of the fuel adjusting needle valve 29 penetrates the bottom wall of the piston type throttle valve 24, and engages with a spring seat 28 formed of a retaining ring engaged with one of a plurality of annular grooves. Is stopped. Spring 25 interposed between spring seat 27 and spring seat 28
As a result, the spring seat 28 and the seat plate 28a
4 is pressed against the bottom wall. The spring seat 27 engages a discontinuous flange 27a with a discontinuous annular groove 24a formed near the bottom wall of the piston type throttle valve 24, and is locked so as not to come off when rotated by a predetermined angle. A spring 13 is interposed between the lid 12 and the bottom of the piston type throttle valve 24. The bottom wall of the piston type throttle valve 24 is provided with a negative pressure intake passage 36 that communicates the negative pressure chamber 14 with the intake path 30.

According to the present invention, at least one annular groove 41 is provided at an intermediate portion of the fuel adjusting needle valve 29, more specifically, at a position where the opening degree of the piston type throttle valve 24 is about 40% and protrudes from the high-speed fuel injection hole 2. , 42 are provided.

Next, the operation of the piston type throttle valve type carburetor according to the present invention will be described. The fuel introduced into the fuel inlet 7 is charged into the fuel storage tank 32 through the inflow valve 9. When the fuel in the fuel tank 32 reaches a predetermined level,
The float 31 rises, the arm 34 rotates clockwise about the support shaft 35, the inflow valve 9 is pressed against the inlet passage of the valve housing 8, and the inflow of fuel is interrupted. Thus, a predetermined level of fuel is stored in the fuel storage tank 32.

When the engine is started and the engine is idling, the butterfly-type throttle valve 21 is substantially in the illustrated state, the piston-type throttle valve 24 is pressed down by the force of the spring 13, and the holding plate 17 is pressed against the upper end wall of the cylinder 20. ing. The fuel in the fuel storage tank 32 is supplied from the low-speed fuel injection hole 23 to the intake passage 30 through the fuel supply pipe 3 and the fuel passage 26.

When the throttle valve 21 is rotated to the vicinity of the fully opened position, the intake negative pressure acting on the high-speed fuel injection hole 2 increases, and the intake negative pressure is introduced into the negative pressure chamber 14 through the passage 36, and the piston type throttle valve 24 Is sucked up against the force of the spring 13. At the same time, the fuel adjustment needle valve 29 is raised, and as shown in FIG. 2, when the opening of the piston type throttle valve 24 exceeds 40%,
The annular grooves 41 and 42 of the fuel adjustment needle valve 29 are exposed to the intake passage 30, and the fuel from the fuel supply pipe 6 exhibits a phenomenon of crawling up along the fuel adjustment needle valve 29.
When they reach 1,42, they accumulate inside the groove. Annular grooves 41, 4
The fuel collected in 2 is immediately blown off by the intake air flowing through the intake passage 30 to be atomized, and is sucked into the engine as an air-fuel mixture.

As described above, the phenomenon in which fuel creeps up from the high-speed fuel injection hole 2 along the back surface of the fuel adjusting needle valve 29 is prevented by the annular grooves 41 and 42.
Is rapidly blown off to the intake passage 30 in response to the opening / closing operation of the piston type throttle valve 24, and is supplied to the engine as an air-fuel mixture, thereby improving the acceleration and responsiveness of the engine.

[0015]

According to the present invention, as described above, the lid is connected to the upper end wall of the vaporizer main body with the membrane interposed therebetween, and a negative pressure chamber is defined above the membrane, and an atmosphere chamber is defined below the membrane. The upper end of a cup-shaped piston-type throttle valve fitted to a cylinder perpendicular to the intake path of the carburetor body so as to be able to ascend and descend is connected to the membrane, and a passage for taking in the intake negative pressure is provided on the bottom wall of the piston-type throttle valve. The piston type throttle valve rises according to the strength of the intake negative pressure against the force of the spring, and the fuel adjusting needle valve protruding from the bottom wall of the piston type throttle valve is moved from the fuel storage tank at the bottom of the carburetor body. In a piston type throttle valve type carburetor fitted to a fuel supply pipe extending to an intake path, the fuel adjusting needle valve is provided with an annular groove which is exposed to the intake path at an opening degree equal to or more than an intermediate opening of the piston type throttle valve. The fuel is crawled from the high-speed fuel injection hole along the fuel adjustment needle valve by the annular groove. Go up, but soon fuel accumulates in the annular groove, likely to be atomized. Further, the fuel is sucked into the engine in a shorter time than when the fuel is crawled on the back surface of the fuel adjusting needle valve and then sucked into the engine, so that the responsiveness of the engine and the acceleration immediately after the start are improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a piston type throttle valve type carburetor according to the present invention.

FIG. 2 is an enlarged side sectional view showing a main part of the piston type throttle valve type carburetor.

FIG. 3 is an enlarged side sectional view showing a main part of a conventional piston type throttle valve type carburetor.

[Explanation of symbols]

2: High-speed fuel injection hole 3: Fuel supply pipe 4: Cylindrical part 5:
Cylindrical part 6: Fuel supply pipe 7: Fuel intake 8: Valve housing 9: Inflow valve 1
2: lid 13: spring 14: negative pressure chamber 15: membrane 16:
Presser plate 17: Presser plate 18: Atmospheric chamber 19: Air intake passage 20: Cylinder 21: Butterfly type throttle valve 22: Valve shaft 23: Low speed fuel injection hole 24: Piston type throttle valve 24
a: Annular groove 25: Spring 26: Fuel passage 27: Spring seat 27a: Flange 28: Spring seat 28
a: Seat plate 29: Fuel adjustment needle valve 30: Intake path 31:
Float 32: Fuel storage tank 33: Fuel jet 34: Arm 35: Support shaft 36: Negative pressure intake passage 40: Vaporizer body 41: Annular groove 42: Annular groove

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[Procedure amendment]

[Submission date] July 27, 2000 (2007.2
7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

When the throttle valve 21 is rotated to the vicinity of the fully opened position, the intake negative pressure acting on the high-speed fuel injection hole 2 increases, and the intake negative pressure is introduced into the negative pressure chamber 14 through the passage 36, and the piston type throttle valve 24 Is sucked up against the force of the spring 13. At the same time, the fuel adjustment needle valve 29 is raised, and as shown in FIG. 2, when the opening of the piston type throttle valve 24 exceeds 20%,
The annular grooves 41 and 42 of the fuel adjustment needle valve 29 are exposed to the intake passage 30, and the fuel from the fuel supply pipe 6 exhibits a phenomenon of crawling up along the fuel adjustment needle valve 29.
When they reach 1,42, they accumulate inside the groove. Annular grooves 41, 4
The fuel collected in 2 is immediately blown off by the intake air flowing through the intake passage 30 to be atomized, and is sucked into the engine as an air-fuel mixture.

Claims (3)

[Claims] 1. A lid is connected to an upper end wall of a vaporizer main body with a membrane interposed therebetween, a negative pressure chamber is defined above the membrane, and an atmosphere chamber is defined below the membrane, and is orthogonal to an intake passage of the vaporizer main body. The upper end of a cup-shaped piston-type throttle valve fitted to a cylinder to be moved up and down is connected to the above-mentioned membrane, and a passage is provided in the bottom wall of the piston-type throttle valve to take in the intake negative pressure. The piston type throttle valve is raised according to the pressure, and the fuel adjusting needle valve protruding from the bottom wall of the piston type throttle valve is connected to the fuel supply pipe extending from the fuel storage tank at the bottom of the carburetor body to the intake path. In the fitted piston type throttle valve type carburetor, the fuel adjusting needle valve is provided with an annular groove which is exposed to the intake passage at an opening degree of the middle of the piston type throttle valve or more. vessel. 2. The piston type throttle valve carburetor according to claim 1, wherein said annular groove is located inside said fuel supply pipe at an idle position of said piston type throttle valve. 3. The piston type throttle valve carburetor according to claim 1, wherein the timing of the fuel blowing from said fuel supply pipe is adjusted by changing the width, number and position of said annular groove.