JP2539187Y2 - Primary choke device for vaporizer - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carburetor for adjusting and controlling the amount and concentration of an air-fuel mixture supplied to an engine, and more particularly to a primary choke device relating to a main fuel system of the carburetor.

[0002]

2. Description of the Related Art A primary choke device for a carburetor is:
It is often used as a means for making the characteristic of the flow rate of fuel supplied from the carburetor to the engine stand (increase) in the high-speed range.
Specifically, the lower end of the main nozzle is immersed below a certain liquid level of the float chamber and the upper end is opened to the intake passage of the vaporizer main body,
On the other hand, an annular air chamber surrounding the main nozzle and opening to the intake passage is provided around the vicinity of the upper end of the main nozzle, and air is introduced into the annular air chamber through the main air passage. At least on the air cleaner side is provided a wall projecting into the intake path. According to the above, the fuel is sucked into the annular air chamber from the upper end of the main nozzle without air being mixed in from the float chamber, and this fuel is mixed with the air supplied to the annular air chamber and sucked into the intake passage. Therefore, the leaning of the air-fuel ratio in the high-speed region of the engine can be suppressed. Primary choke devices for such vaporizers are known.

[0003]

According to the primary choke device of the conventional carburetor, the wall portion is provided at least on the air cleaner side of the annular air chamber, so that the annular air chamber and the upper end opening of the main nozzle are raised. Although it is possible to apply a negative pressure, the suction performance of the fuel is improved and the leanness of the air-fuel mixture is suppressed, but a large vortex may be generated on the inner surface of the wall on the engine side. In addition, fuel sucked from the upper end opening of the main nozzle is trapped in the annular air chamber, which hinders atomization of the fuel, deteriorating driver stability during engine acceleration operation, or mixing air into each cylinder in a multi-cylinder engine. From the point of uniform distribution of

[0004] The primary choke device for a carburetor according to the present invention has been made in view of the above-mentioned problem, and the primary choke device for a carburetor promotes atomization of fuel sucked into a suction passage from a main nozzle to thereby enhance driver drivability during acceleration operation. It is an object of the present invention to provide the above-described apparatus that can improve the air-fuel ratio and make the distribution of the air-fuel mixture uniform among the cylinders.

[0005]

According to the primary choke device of the carburetor according to the present invention, in order to achieve the above object, at least the air cleaner surrounds at least the air cleaner side of the annular air chamber and is provided so as to protrude into the intake passage. A groove is formed from the upper end of the provided wall toward the base.

[0006]

During operation of the engine, a negative pressure in the intake passage acts on the inner side surface of the wall on the engine side. At this time, an airflow is generated along the longitudinal axis of the intake passage through the groove formed in the wall. According to this, the vortex generated on the engine-side inner surface of the wall is deflected to flow in the longitudinal axis direction of the intake passage, and the fuel sucked out from the main nozzle is caught in the annular air chamber. It is suppressed, and the atomization of fuel is promoted.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a primary choke device for a vaporizer according to the present invention will be described below with reference to the drawings. 1 is a longitudinal sectional view, FIG. 2 is a transverse sectional view taken along line AA in FIG. 1, and FIG. 3 is a longitudinal sectional view taken along line BB in FIG.

Reference numeral 1 denotes a carburetor body in which an intake passage 2 penetrates laterally, and the intake passage 2 is opened and closed by a throttle valve 3. Float chamber main body 4 is arranged below vaporizer main body 1,
A float chamber 5 is formed by the vaporizer main body 1 and the float chamber main body 4, and a constant liquid level is formed in the float chamber 5 by a float 6, a valve seat (not shown) and a float valve. 7
Is a main nozzle disposed at the projection 1A of the carburetor body 1, the tip of the main nozzle 7 opens to the intake passage 2, and the other end is below a certain liquid level of the floating chamber 5 via the main fuel jet 7A. Immerse yourself in Note that the main nozzle 7 may project into the intake path 2.
8 surrounds the outer periphery 7A of the tip of the main nozzle 7 and
An annular air chamber that opens to the intake passage 2, and air controlled by the main air jet 9 is introduced into the annular air chamber 8 through the main air passage 12. Reference numeral 10 denotes a wall surrounding at least the air cleaner side (the right side in FIG. 1) of the annular air chamber 8, and the wall 10 protrudes into the intake passage 2.
And in the present invention, in order to achieve the above object,
The groove 11 extends from the upper end 10A of the wall 10 toward the base 10B.
Is drilled.

According to the primary choke device of the carburetor of the present invention having the above-described structure, the opening of the annular air chamber 8 to the intake passage 2 and the main nozzle 7 during operation of the engine.
A large negative pressure is generated at the tip opening of the main nozzle 7 by the wall 10, fuel is sucked from the tip opening of the main nozzle 7, and the fuel in the annular air chamber 8 is mixed with the fuel,
An air-fuel mixture is formed.

According to the fact that the groove 11 extending from the upper end 10A to the base 10B is formed in the wall 10, the opening of the annular air chamber 8 to the intake passage 2 and the main nozzle 7 are formed.
In the front end opening, an increased airflow is generated along the longitudinal axis of the intake path 2. Thus, the vortex generated on the engine-side inner surface 10 </ b> C of the wall 10 is weakened by the flow along the longitudinal axis of the intake passage 2 and deflected to the flow of the intake passage 2 in the longitudinal axis direction. Therefore, the phenomenon that the air-fuel mixture is trapped in the annular air chamber 8 due to the vortex is reduced. According to the above, the air-fuel mixture formed by the main nozzle 7 and the annular air chamber 8 smoothly flows to the side along the longitudinal axis direction of the intake passage 2, and the atomization of the air-fuel mixture can be achieved. Thus, it is possible to smoothly and promptly supply the air-fuel mixture to the engine, thereby improving the driver stability during the acceleration operation of the engine and uniformly distributing the air-fuel mixture to each cylinder in a multi-cylinder engine. It is more effective in reducing harmful exhaust gas components.

The main nozzle 7 is provided with a groove 11 as shown in FIG.
Drilling along the longitudinal axis Y-Y of
Is formed at the center of the intake path 2 in the longitudinal axis direction, which is particularly preferable from the viewpoint of the distribution of the air-fuel mixture.

Further, the shape of the groove 11 is not limited to the embodiment shown in the figure, and may be, for example, a triangular groove, a trapezoidal groove, a U-shaped groove, a V-shaped groove, and a plurality of grooves, which are optimal when setting the engine. Selected. Further, the present embodiment shows the butterfly type carburetor, but can be applied to a sliding throttle valve type carburetor.

[0013]

As described above, according to the primary choke device of the carburetor according to the present invention, the vortex caused by the entrainment generated on the inner side surface of the wall portion on the engine side is particularly directed to the longitudinal axis of the intake passage flowing through the groove of the wall portion. Can be largely eliminated by the flow along the air flow, and the adhesion of the air-fuel mixture to the pipe wall due to the vortex flow can be reduced, so that the air-fuel mixture can be atomized. Thus, the distribution of the air-fuel mixture to each cylinder can be improved. In addition, according to the fact that the groove is formed along the longitudinal axis of the main nozzle, the mixture can be evenly distributed particularly to each cylinder.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a primary choke device in a vaporizer according to the present invention.

FIG. 2 is a cross-sectional view taken along line AA of FIG.

FIG. 3 is a longitudinal sectional view taken along line BB of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vaporizer main body 2 Intake path 4 Float chamber main body 7 Main nozzle 8 Annular air chamber 10 Wall 10A Upper end 10B Base 11 Groove

Claims (2)

(57) [Scope of request for utility model registration] 1. A carburetor body 1 through which an intake passage 2 penetrates.
A float chamber 5 having a constant liquid level formed therein by a float chamber main body 4 disposed below the vaporizer main body 1, a main nozzle 7 connected below the constant liquid level of the float chamber 5 and opening to the intake passage 2, Surrounding the outer periphery 7A of the tip of the main nozzle 7 and the intake passage 2
And an annular air chamber 8 into which air is introduced via a main air passage 10, and a wall 10 surrounding at least the air cleaner side of the annular air chamber 8 and projecting into the intake passage 2. In the primary choke device of the carburetor provided with the upper end portion 10 of the wall portion 10 on the air cleaner side.
A primary choke device for a carburetor, wherein a groove 11 is formed from A to a base 10B. 2. The groove is defined by a longitudinal axis Y of the main nozzle 7.
The primary choke device for a carburetor according to claim 1, wherein the primary choke device is drilled along -Y.