JPH0830447B2 - Vaporizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a dual carburetor in which a carburetor main body is provided with a plurality of intake passages, and a single float chamber is arranged in the lower center of these intake passages.

<Prior Art> Conventionally, in such a carburetor, a main nozzle is arranged on the center line of each intake passage.

<Problems of the prior art> For this reason, each of the main nozzles is arranged at a position away from the center of the float chamber, and when the oil level tilts when the carburetor tilts, the oil level in the left and right main nozzles is large. Make a difference. That is, the oil level in one main nozzle rises and a large amount of fuel is ejected from this, whereas the oil level in the other main nozzle falls and the fuel ejected from the main nozzle decreases. As described above, when the carburetor is tilted, the fuel injection amounts to the left and right intake passages are significantly different, which causes a defect in the engine.

<Purpose> The present invention has been made in view of the above-described drawbacks, and provides a double vaporizer in which right and left fuel injection amounts do not significantly change even when the carburetor is inclined and the oil surface is inclined, and the atomization is good. The purpose is to

<Structure> In the present invention, a main nozzle that hangs down from the intake passage into the float chamber is eccentrically arranged from the center of each of the intake passages toward the center of the float chamber, and at the bottom of the intake passage,
It is characterized in that a small diameter venturi is provided substantially coaxially with the main nozzle, and the throttle valve is provided with a cutaway facing the small diameter venturi and eccentric from the center of the intake passage.

<Operation> According to the present invention configured as described above, since the main nozzle is arranged near the center of the float chamber, even when the oil level is inclined when the carburetor is inclined, the inside of the left and right main nozzles The change in the oil level is small, and the change in the fuel injection amount from each of these main nozzles is small. Therefore, when the carburetor is tilted, the fluctuation of the air-fuel mixture concentration generated in the left and right intake passages becomes small.

In addition, when the throttle valve is low opening, only the small diameter venturi is opened to accelerate the flow velocity, and the cutaway facing the small diameter venturi causes an appropriate intake negative pressure to act on the main nozzle. Since the cutaway is eccentric with the Venturi and a swirl effect is generated in the intake negative pressure, atomization of the fuel ejected from the main nozzle at each opening of the carburetor can be improved.

<Example> An example of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, 1 is a carburetor main body, 2 and 3 are intake passages provided in parallel with the carburetor main body, 4 is a float chamber provided at the center of the lower side of each of the intake passages 2 and 5, and 5. 6 is a throttle valve that moves up and down orthogonally to the intake passages 2 and 3, and 7 and 8 are venturis. At the bottom of the intake passages 2 and 3, the main nozzles 9 and 10 and the slow system port 11 are eccentric to the center of the float chamber 4 from the center lines A and B of the intake passages 2 and 3.
12 is provided, and small-diameter venturis 13 and 14 are formed substantially coaxially with the main nozzles 9 and 10. Further, cutaways 21 and 22 eccentric from the center of the intake passage are provided on the bottom surface of the throttle valves 5 and 6 on the intake upstream side so as to face the small-diameter venturis 13 and 14. Therefore, as shown in FIG. 3, when the throttle valves 5 and 6 are at a low opening, only the small diameter venturi 13 and 14 formed substantially coaxially with the main nozzle are opened, and the intake negative pressure applied to the main nozzle by the cutaway is also opened. Since the pressure is properly adjusted, the flow velocity of the air flowing through the venturis 13 and 14 is increased, and the atomization of the fuel ejected from the main nozzles 9 and 10 and the slow system ports 11 and 12 is improved. Further, as shown in FIG. 4, when the throttle valves 5 and 6 are opened at medium and high positions, the normal venturi 7 and
8 is opened, the main nozzles 9 and 10 and the venturi 7 and 8 are eccentric, and the fuel ejected from the main nozzles 9 and 10 produces a swirl due to the swirl effect, and the air flowing in the venturi is mixed. It is carried out sufficiently and atomization becomes good. Further, in the middle and high opening range, the cutaways 21 and 22 are also eccentric with the venturi 7.8, so that the swirl effect is promoted and the atomization of the fuel is further improved. 15
Reference numeral 16 is a slow jet immersed in the oil surface of the float chamber 4, and like the main nozzles 9 and 10, the intake passages 2 and 3 are provided.
It is eccentrically arranged on the center side of the float chamber 4 with respect to the center lines A and B. Reference numerals 17 and 18 denote jet needles depending from the throttle valves 5 and 6, and the jet needles 17 and 18 are inserted into the main nozzles 9 and 10. 19 and 20 are the main jets.

According to the present invention thus configured, since the main nozzles 9 and 10 are disposed near the center of the float chamber 4, even if the carburetor tilts and the oil level in the float chamber 4 tilts, Fluctuations in the oil level in the left and right main nozzles 9 and 10 are reduced, and fluctuations in the air-fuel mixture concentration when the carburetor is tilted can be made extremely small.

Also, when the throttle valves 5 and 6 are low, the small diameter venturi 13
・ Only 14 is opened to increase the flow velocity, and the cutaways 21 and 22 facing the small diameter Venturi 13 and 14 cause proper intake negative pressure to act on the main nozzles 9 and 10. In addition, the main nozzles 9 are opened at medium and high openings.・ 10 and Cutaway 21 ・ 22 are eccentric with Venturi 13 ・ 14, and swirl effect occurs in the intake negative pressure. Therefore, atomization of fuel ejected from main nozzle 9 ・ 10 at each opening of the carburetor is improved. be able to.

<Effect> As described above, according to the present invention, in a carburetor having a plurality of intake passages and a single float chamber arranged in the lower center of the intake passages, a main nozzle that hangs down from each intake passage into the float chamber. Are arranged eccentrically to the center of the float chamber from the center of each intake passage, so that the fluctuation of the oil level in each main nozzle when the carburetor is tilted is small, and the fluctuation of the fuel amount injected into the intake passage is small. Becomes smaller. Therefore, even when the carburetor is tilted, the change in the air-fuel mixture concentration is small, and the engine can be operated stably.

Further, when the throttle valve is at a low opening degree, the small-diameter venturi and the cutaway provided on the throttle valve facing the small-diameter venturi can increase the flow velocity, and the intake negative pressure acting on the main nozzle can be optimally controlled. Further, since the main nozzle and the cutaway are eccentric with the Venturi when the throttle valve is in a middle and high opening degree, the fuel ejected from the main nozzle produces a swirl flow due to the swirl effect, thereby promoting atomization.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the carburetor of the present invention, FIG. 2 is a sectional view taken along the line I--I of FIG. 1, and FIGS. 3 and 4 are a low opening and a high carburetor of the present invention. It is a longitudinal cross-sectional view showing the respective opening states. 1 ... Vaporizer main body, 2.3 ... Intake passage, 4 ... Float chamber, 9/10 ... Main nozzle, 13.14 ... Small diameter venturi, 21.22 ... Cutaway.

Claims (1)

[Claims] 1. A carburetor in which a float chamber is disposed in the lower center of a plurality of intake passages provided in a carburetor body, wherein a main nozzle that hangs down from the intake passage into the float chamber is provided from the center of each intake passage. Is arranged eccentrically on the center side of the intake passage, and a small-diameter venturi is provided at the bottom of the intake passage substantially coaxially with the main nozzle. Further, the throttle valve is eccentric from the center of the intake passage facing the small-diameter venturi. A vaporizer characterized by having a cutaway.