JPH0430370Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of an emulsion tube for emulsifying fuel for a main nozzle in a carburetor by mixing it with air.

[Prior Art] The emulsion of fuel for the main nozzle in a carburetor is carried out in a main well which communicates with the float chamber at the lower part via the main jet and which has a transverse main passage to said main nozzle at the upper end. An emulsion tube with a number of small holes at the bottom of the air bleed is inserted, and the air introduced from the air bleed at the upper end into the emulsion tube is passed through the many small holes at the bottom to the emulsion tube and the main air bleed. This is done by ejecting the emulsion into an annular emulsion chamber between the well and the emulsion chamber, for example, as described in 1983.
It is well known as described in Publication No.-75543.

[Problem that the invention attempts to solve]

However, when fuel is emulsified using an emulsion tube as described above, there is a problem between the outer diameter of the emulsion tube and the inner diameter of the main well, as described below.

That is, if the outer diameter of the emulsion tube is made sufficiently smaller than the inner diameter of the main well, the volume of the annular emulsion chamber between the emulsion tube and the main well increases. However, when the fuel supply in the carburetor is switched from the slow system to the main system with the opening of the throttle valve, By making the diameter of the emulsion tube small, a large amount of fuel flows out from the main nozzle at once, resulting in a rich air-fuel ratio in the intake air mixture, which increases the amount of fuel in the exhaust gas.
A problem occurs when the CO concentration increases.

On the other hand, if the outer diameter of the emulsion tube is made large so that it approaches the inner diameter of the main well, the opening of the main passage leading to the main nozzle into the main well can be made larger in diameter. Because it is narrowed by Since the volume of the annular emulsion chamber is reduced by increasing the diameter of the emulsion tube, emulsion formation of the fuel in the emulsion chamber is impaired.
Since the flow rate of fuel to the main nozzle becomes unstable, surging occurs in the internal combustion engine and drivability deteriorates.

In addition, as other prior art
The publication discloses that the outer diameter of the emulsion tube is
It is proposed to make the diameter large so that it approaches the inner diameter of the main well, and to provide a vertical groove on the outer peripheral surface of the emulsion tube extending upward from the lower end. Since the expansion of the volume of the emulsion chamber is small, it is hardly possible to prevent the occurrence of surging, and furthermore, providing the above-mentioned vertical grooves on the outer circumferential surface of the emulsion tube This will result in a significant increase in the cost required for processing the tube.

The object of the present invention is to provide an emulsion tube that can solve this problem without increasing the cost required for processing the emulsion tube.

[Means for solving problems]

To achieve this objective, the present invention provides an emulsion tube inserted into a vertical main well whose lower part communicates with the float chamber via the main jet and whose upper part opens with a lateral main passage to the main nozzle. The emulsion tube is formed into a stepped tube in which the upper part of the emulsion tube corresponding to the horizontal main passage is formed into a cylindrical large diameter part, and the part below this is formed into a small diameter part concentric with the large diameter part. A plurality of small holes are provided in the small diameter part at the lower part of the large diameter part, and the step part at the lower end of the large diameter part is arranged in the horizontal main passage from a position approximately at the same height as the center of the horizontal main passage. It is configured to be located within a height range up to approximately the same height as the bottom surface.

[Action and effect of the invention]

By making the upper part of the emulsion tube inserted into the main well, which corresponds to the horizontal main passage, into a large diameter part, the opening of the main passage leading to the main nozzle into the main well is made larger. Since the diameter can be narrowed, it is possible to reliably prevent a large amount of fuel from flowing out from the main nozzle at once at the beginning when the fuel supply in the carburetor is switched from the slow system to the main system.

On the other hand, by making the emulsion tube a stepped tube with a large diameter at the top and a small diameter at the bottom, and by providing many small holes in the small diameter section, the air introduced into the emulsion tube from the air bleed is The emulsion is ejected into an annular emulsion chamber formed between the small diameter portion of the emulsion tube and the main well.

and the stepped portion at the lower end of the large diameter portion of the emulsion tube is located within a height range from approximately the same height as the center of the main passage to approximately the same height as the bottom surface of the main passage. As a result, the length of the emulsion chamber in the vertical direction becomes longer, and the volume of the emulsion chamber can be greatly increased by both this and the fact that the lower part of the emulsion tube is made small in diameter. , it is possible to reliably promote emulsion formation of the fuel within the emulsion chamber.

Therefore, according to the present invention, when the fuel supply in the carburetor is initially switched from the slow system to the main system with the opening of the throttle valve, the CO concentration in the exhaust gas increases and surging occurs in the internal combustion engine. This has the effect of preventing deterioration of drivability due to this occurrence.

Moreover, since the large diameter part of the emulsion tube is cylindrical and the small diameter part is configured concentrically with the large diameter part, the emulsion tube can be manufactured by cutting or grinding using a lathe or the like. Since there is no need to carve vertical grooves on the outer peripheral surface of the emulsion tube as in the prior art, there is no increase in the cost required for processing the emulsion tube. .

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 indicates a carburetor main body, reference numeral 2 indicates a main nozzle, and reference numeral 3 indicates a vertically oriented main well extending in the vertical direction. 3
The lower part of the main well 3 communicates with a float chamber 5 in the carburetor through a main jet 4, and the upper part of the main well 3 opens into a main passage 6 extending horizontally to the main nozzle 2.

Reference numeral 7 indicates an emulsion tube inserted into the main well 3, and an air bleed 8 is provided at the upper end of the emulsion tube 7.

Then, the emulsion tube 7 is connected to the main passage 6 of the emulsion tube 7.
The upper part corresponding to
The part below this is configured as a stepped tube with a small diameter part 10 having a small diameter d concentric with the large diameter part 9. 1 small hole in the lower part
2 are provided in large numbers, and the step portion 9a at the lower end of the large diameter portion 9 is located at approximately the same height as the bottom surface 6a of the main passage 6.

With this configuration, the air introduced into the emulsion tube 7 from the air bleed 8 flows through each small hole 12 in the small diameter section 10 of the emulsion tube 7 into the emulsion chamber 13 outside the small diameter section 10. In this case, the step 9a at the lower end of the large diameter portion 9 of the emulsion tube 7 is positioned at approximately the same height as the bottom surface 6a of the main passage 6 to the main nozzle 2. As a result, the emulsion chamber 13 on the outside of the small diameter portion 10 becomes longer in the vertical direction and its volume increases, so that it is possible to promote emulsion of the fuel within the emulsion chamber 13, and at the same time, the emulsion chamber 13 is 7, by providing the large diameter portion 9 at a position corresponding to the main passage 6, the main well 3 of the main passage 6
Since the opening to the main nozzle 2 is narrowed, it is possible to prevent a large amount of fuel from flowing out at once when the fuel starts flowing out from the main nozzle 2.

According to the experiment, emulsion tube 7
The height position of the step portion 9a at the lower end of the large diameter portion 9 is determined by the height dimension L from approximately the same height position as the center 6b of the main passage 6 to approximately the same height position as the bottom surface 6a of the main passage 6. It was confirmed that there was no significant difference in effectiveness as long as the location was within the range.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view showing the main parts of a carburetor, and FIG. 2 is an enlarged view of the main parts of FIG. 1. 1... Carburetor body, 2... Main nozzle, 3...
...Main well, 4...Main jet, 5...
Float chamber, 6... Main passage, 6a... Bottom of main passage, 6b... Center of main passage, 7...
Emulsion tube, 8... Air bleed, 9
...Large diameter part, 9a... Reinforced diameter part at the lower end of the large diameter part, 1
0...Small diameter part, 12...Small hole.

Claims (1)

[Scope of utility model registration request] The lower part connects to the float chamber 5 via the main jet 4.
In the emulsion tube 7 inserted into the vertical main well 3, which communicates with The upper part corresponding to the main passage 6 is formed into a cylindrical large diameter part 9, and the part below this is formed into a stepped tube formed into a small diameter part 10 concentric with the large diameter part 9, and the small diameter part at the lower part. 10 is provided with a large number of small holes 12, and the large diameter portion 9 is inserted into the lateral main passage 6 from a position where the step 9a at the lower end of the large diameter portion 9 is approximately at the same height as the center 6b of the lateral main passage 6. An emulsion tube in a vaporizer, characterized in that it is configured to be located within a height dimension L up to approximately the same height as a bottom surface 6a.