JPH03105050A - Single trunk carburetor - Google Patents

Abstract

PURPOSE:To improve the suction of main fuel even in the perfect opening low speed operation and supply the demanded mixed gas with the simple constitution, by forming projections in annular form, projecting from the wall of a suction passage to an intake passage, on the plane crossing with the intake passage axis line on a venturi upstream side. CONSTITUTION:A carburetor is equipped with a choke valve 2 in the intake passage 8 in an air horn 1. Further, a main nozzle 6 is installed onto a small venturi 5 in a large venturi 4 of the carburetor body 3 connected with the air horn 1 through a gasket 7. In this constitution, on the plane perpendicular to the axis line of the intake passage 8, an annular projection 11 projecting into the intake passage 8 from a suction passage wall 9 is formed integrally at the downstream edge of the air horn 1. A turbulent flow is formed in the intake by the projection 11, and the speed distribution of the air in the radial direction in the intake passage 8 is made maximum at the center. The suction of fuel from a nozzle port 6a at the center part of the venturi 5 is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a single-barrel carburetor with a set of venturis for supplying fuel to a general purpose or automobile engine. [Prior art] A set of benches. In other words, a single-barrel carburetor has one intake passage. Since a single intake passage supplies the required air to the entire operating range of the engine, the intake passage diameter is larger than that of multiple-body carburetors such as two-stage carburetors. Therefore, the Venchery diameter is also made large. For this reason, the pliers for the same amount of air required by the engine. The intake air flow rate in the IJ section is lower in a single-shell carburetor than in a multi-barrel carburetor, so the main fuel can be sucked out by reducing the drop between the oil level in the constant oil level chamber and the nozzle opening of the main nozzle. It is designed to be easy. However, although these methods can supply the required air-fuel mixture at partial load or at full-throttle speed, they are not reliable and cannot sufficiently suck out the main fuel at full-throttle low speed when the negative pressure is low. There is a problem in that even if it is thin, the expected output cannot be obtained.

As a countermeasure, it has been considered to make the main nozzle variable or to make the small bench movable so that the main fuel can be better sucked out at full throttle and low speed. However, it is complicated and expensive and is not suitable for practical use. [Problems to be Solved by the Invention] The present invention attempts to solve the above-mentioned problem that there is no means suitable for a single-barrel carburetor that can sufficiently suck out the main fuel and supply a predetermined mixture at full throttle and low speed. It is a thing,
The purpose of the present invention is to provide a single-oil carburetor that has a very simple structure with no moving parts and can supply the required air-fuel mixture at full throttle and low speed. [Means for Solving the Problems] The present invention provides an annular 6-shaped protrusion that protrudes from the intake passage wall to the intake passage on a surface intersecting the intake passage thin line of the Vencheri upper joint.
This provision is a means to solve the above problem.

[For production]

The intake air flowing from the air cleaner towards Penchi Island Ri is turbulent due to the protrusions. The velocity distribution of the intake air flow in the radial direction of the intake passage caused by the turbulent flow is maximum at the center, and the fuel can be sucked out from the nozzle opening located at the center of the bench.

That is. Since turbulent flow exhibits an extremely large pressure drop compared to laminar flow, even when the intake air flow rate is low at full throttle, sufficient fuel can be sucked out and the required air-fuel mixture can be supplied.

[Embodiment] An embodiment of the present invention will be explained with reference to the drawings. 1 is an air horn, 2 is a choke valve,
3 is the carburetor main body, 4 is a large pliers, 5 is a small pliers, 6 is the main nozzle, 7 is a gasket, the intake passage 8 extends vertically, and the nozzle 6a is the suction passage 8.
The opening is approximately on the central transmissive line. In the embodiment shown in Fig. 1, an annular plate-shaped center holder 1l, which is placed on a plane perpendicular to the intake passage axis and projects from the intake passage wall 9 to the intake passage 8, is integrally molded on the lower R end of the air horn 10. .

In addition, the embodiment shown in Figure O2 is the intake path sIIlj! An annular plate-shaped projection 12 protruding from the intake passage wall 9 to the intake passage 8 on a plane perpendicular to the air horn 1 is integrally formed at the upstream end of the air horn l. Protrusion 11 of these two embodiments. L! is formed at the same time when the air horn 1 is die-cast.

In the embodiment shown in Fig. 3, an annular plate 13 made of metal 1 or hard synthetic resin has a large number of protrusions 14 projecting in the direction of the bait with appropriate gaps, and is overlapped with a gasket 7 to form an air horn. The protrusion 14Fi protrudes from the intake passage wall 9 into the intake passage 8 on a plane perpendicular to the intake passage axis. In the embodiment shown in FIG. 4, a trumpet-shaped projection l6 is formed protruding from the inside surface of the annular plate 15 similar to that described above, which is overlapped with the gasket 7 and fixed between the air horn 1 and the carburetor main body 3. The protrusion 16 curves and protrudes from the intake passage wall 9 toward the intake passage 8 toward the downstream bait on a plane perpendicular to the intake passage axis.

In the embodiment shown in Fig. 5, the inner diameter of the gasket 7 is reduced and the part that protrudes into the intake air passage 8 is made into an annular plate-shaped protrusion 17, and this protrusion l7 is also perpendicular to the axis of the intake passage. It protrudes from the intake passage wall 9 into the intake passage 8 on the surface.

In the structure of each of the embodiments described above, when intake air flows from an air cleaner (not shown) to the pipe, the intake air in a laminar flow state generally flows through the protrusions 11, 12, 14, 16.
．． 17, the flow becomes turbulent and flows through the large bench IJ4 and the small bench 5 concentric therewith. Intake path 8
is the conduit. The velocity distribution of the intake air flow in the radial direction of the intake passage due to the turbulent flow generated therein is maximum at the center.
Since the pressure drop due to turbulence H is approximately proportional to the square of the velocity, it shows an extremely large pressure drop compared to laminar flow.
Even when the intake air flow rate is low at full throttle, a high negative pressure acts on the nozzle nozzle 6a opened at the center of the small penturi 5 located approximately on the central axis of the intake passage 8, and a sufficient amount of raw fuel is sucked out. be able to. still. According to the inventor's observations, it was confirmed that the mixture does not become richer than necessary at partial load or at full throttle high speed. [Effect of the invention] According to the present invention. pliers. With a very simple configuration that has no moving parts, such as an annular protrusion installed in the intake passageway upstream, the main fuel can be effectively sucked out at full throttle and at low speeds, and the required mixture can be supplied to the engine to improve output. It is possible.

[Brief explanation of drawings]

Figures O1, O2, O3, O4, and O5 are vertical cross-sectional partial views showing different embodiments of the present invention.

Claims (1)

[Claims] A single-barrel carburetor characterized in that a protrusion is provided in an annular shape on a surface that intersects the axis of the intake passage on the upstream side of the venturi and projects from the intake passage wall into the intake passage.