JPS6332154A - Two-stage type carburetor - Google Patents

Abstract

PURPOSE:To miniaturize the whole, when a variable venturi piston being operated by a negative pressure and an adjacent variable venturi piston being operated by an external operation are provided, by arranging both pistons so as to be staggered in the lengthwise direction of venturi pipes. CONSTITUTION:The fuel from the float chamber 40 of a carburetor is supplied to a high-speed variable venturi tube 31 and a low-speed variable venturi tube 21. in the high-speed variable venturi tube 31, a piston valve 32 which is fixed to a diaphragm 35 being operated by a negative pressure through a hole 32b is provided. In the low-speed variable venturi tube 21, a piston valve 22 which is moved up and down by a spindle 23a being turned by external operation is provided. The positions of both piston valves are arranged so as to be staggered in the lengthwise direction of venturi pipes by l. Thus, both piston valves can be arranged so as to be adjacent, and the whole can be miniaturized.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a variable venturi type carburetor for low speeds for supplying a fuel mixture gas into the combustion chamber of an internal combustion engine at low speeds, and a high speed type carburetor for supplying a fuel mixture gas at high speeds to the combustion chamber of an internal combustion engine. This invention relates to a technique that can be applied to a two-stage vaporizer in which a variable venturi vaporizer and a variable venturi vaporizer are arranged in parallel.

[Prior Art] This type of two-stage carburetor consists of a set of a low-speed variable venturi carburetor and a high-speed variable venturi carburetor that are separately manufactured, and each set is used for a multi-cylinder internal combustion engine. It is more compact than connecting to the intake port of each cylinder constituting the combustion chamber, and it does not easily protrude in the width direction of the vehicle body even when a large number of them are installed side by side. Recently, it has been proposed for use in automatic two-axle vehicles.

[Problems to be Solved by the Invention] However, as shown in the above-mentioned publication, for example, in the conventionally proposed two-stage carburetor, the low-speed venturi carburetor on the lower side is forcibly activated by an external operation. The negative pressure responsive diaphragm 11 of the high-speed variable venturi carburetor was moved parallel to the diaphragm chamber 1 to avoid interference with the diaphragm chamber 1 in which it was housed. - This becomes an obstacle to the expansion of the intake system, and the size increases in the width direction by the distance, and as a result, this type of intake system 11
It was extremely difficult to apply this to a multi-cylinder engine. [Purpose of the Invention] This invention was made in order to solve the above problems, and it is a variable venturi type carburetor for high speeds and a variable venturi type for low speeds. The purpose is to provide a two-stage carburetor that is compact in the width direction by arranging the carburetors as close to each other as possible.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the two-stage carburetor according to the present invention has a negative pressure response for adjusting the passage area of the Venturi tube. A high-speed variable venturi type carburetor section equipped with one diaphragm chamber for accommodating a diaphragm;
A low-speed variable venturi type carburetor part that forcibly adjusts the passage area of the venturi pipe from the outside by a piston valve that is slidably operated by forced operation from the outside is installed side by side, and the two venturi pipes are used for internal combustion. In a two-stage carburetor which is connected together to the intake ports of the same cylinder of an engine, the positions of the two screw valves are different from each other in the length direction of the venturi tube. The tubes are arranged close to each other.

[Operation] By arranging the two piston valves so that their first faces are different from each other in the length direction of the venturi tube, the carburetor parts can be brought close to each other.

[Embodiment] What is shown in FIG. 3 as a side view and in FIG. 4 as a partial plan view is a two-stage carburetor 1o according to the present invention.
``White J Nikan'' (11) was applied.

In this two-axle automatic vehicle 1, a plurality of (four in this embodiment) cylinders 3 constituting a combustion chamber of an internal combustion engine 2 are arranged in a forward-inclined state in parallel along the width direction of the vehicle body.

Each cylinder 3 is illustrated as being of a down draft type (downward ventilation type). As shown in FIG. 4, two-stage carburetors 10 according to the present invention are arranged side by side along the width direction of the vehicle body so as not to protrude from the width W of the vehicle body frame zs2.

As shown in FIGS. 4, 5, and 6, a plurality of these two-stage vaporizer r+ios are connected in the horizontal direction to form a unit.

As shown in FIG.
- (47) The carburetor portion 30 is spaced close to Q in the lateral direction (width direction), and is shifted by Q2 (Fig. 5) in the direction of 1 fir and p3 (Fig. 2) in the height direction. Kombaku I
- The configuration is such that they are integrally installed in parallel.

[The variable venturi type carburetor part 30 for Wakkifu speed has a large diameter variable venturi 11 provided approximately in the center! ? 31, and the venturi tube 3 is slidably inserted into a guide tube 30a provided vertically in communication with the venturi tube 30a.
A large-diameter piston valve 32 that changes the flow path area of 1;
Apply a return force to the screw valve 32 in the direction of reducing the flow path area of the venturi tube 31. A diaphragm chamber 34 (FIGS. 1 and 7) communicates with the venturi IW 31 through a communication hole 32b provided in the diaphragm chamber 32a, and a Slide the piston valve 32 and diaphragm 35.
and a float chamber 4 as a fuel reservoir chamber provided on the opposite side of the venturi pipe 31 facing the guide tube 30a.
0.

On the other hand, the low speed variable venturi type carburetor portion 2o is
By shifting Q2 in the vertical direction with respect to the high-speed variable venturi type carburetor part 3o so that its longitudinal end is under the diaphragm 1 chamber 34, the diaphragm 11 chamber 34 and the flow 1-chamber 4o The high-speed variable venturi type carburetor part 30 is housed in the space between the
The iu is installed in close proximity to the float chamber 40 and in a state where the float chamber 40 is shared with the float chamber 40.

This low speed variable venturi type carburetor section 20 is.

As shown in FIGS. 5 and 6, the venturi'! 231 and a small-diameter venturi tube 21 provided in parallel with the venturi tube 231, and a guide tube 20a provided perpendicularly and parallel to the guide tube 30a in communication with the venturi tube 231. The venturi tube 21 is equipped with a small-diameter screw 1-valve 22 that changes the flow path area of the venturi tube 21, and the guide tube 20a and the piston valve 22 are venturi-shaped with respect to the guide tube 30a and the piston valve 32 of the high-speed variable venturi type carburetor 30. 12! , 31 are shifted by Q3 in the length direction.

In this way, by arranging the screw valves 22, 32 to be offset from each other in the length direction of the venturi tubes 21, 31, the thickness t of the partition wall 11 between the venturi tubes 21, 31 can be maintained sufficiently. Above, the venturi tube 21.31 and the piston valve 22.32 are connected to each other and thus the carburetor part 2.
0.30 can be moved closer.

The sliding action of the piston valve 22 is caused by an external accelerator (
It is operated by a rotating shaft 23a which is rotated by an operation (not shown) via a link mechanism 23 (FIG. 6).

A needle valve 37 is attached to the bottom 22a of the piston valve 22, and the needle valve 37 is inserted into the nozzle 24 that guides the fuel liquid in the float chamber 4o into the venturi pipe 21. The flow path area of 24 is changed.

The opening ends of the large and small venturi pipes 31 and 21, which are disposed obliquely and shifted from each other in the vertical direction, are surrounded by an air cleaner (not shown) or the same cylinder 3, respectively. Mounting frames 50 and 51 for mounting together with the intake port (not shown) are provided in an elliptical shape surrounding both of them.

By the way, in the large-diameter venturi pipe 31, a butterfly-type valve B that changes the flow path area is connected to the venturi 'l' of the rotating shaft 23a. 31 in a fixed state.

In the two-stage carburetor 10 having the above configuration, when the rotating shaft 23a is rotated by an external accelerator operation, the small-diameter piston valve 22 first slides to increase the flow path area of the small-diameter Venturi tube 21. A low speed variable venturi type carburetor section 20 functions. After that, when the rotating shaft 23a is further rotated, the opening degree of the butterfly type valve (not shown) increases, and the negative pressure responsive J type diaphragm 1135 is activated, which causes the large piston valve 32 to slide at high speed. A variable venturi type vaporizer section 30 functions.

The two-stage carburetor 10 according to this embodiment has the diaphragm 1 of the high-speed variable venturi carburetor portion 30 as described above.
Under the chamber 34 is a variable venturi type carburetor section 20 for low speed.
In addition, the two piston valves are arranged at different positions in the length direction of the Venturi tube.
Venturi tube 21.31 and piston valve 22.3
As a result, the high speed variable venturi type carburetor section 30 and the low speed variable venturi type carburetor section 20 can be made quite close to each other, and the width is significantly reduced compared to the conventional method. It becomes compact in the direction. Note that the present invention can also be applied to a horizontal ventilation type vaporizer.

[Effects of the Invention] According to the present invention, there are two piston valves: the carburetor that is automatically operated by a negative pressure responsive diaphragm, and the carburetor that is created by forced operation from the outside. Since the positions of the venturi tubes are different from each other in the length direction of the venturi tube, the distance between the two carburetors can be made extremely close to each other, and as a result, the width direction of the venturi tube can be made significantly more compact than before. It becomes a two-stage vaporizer.

[Brief explanation of the drawing]

1 to 7 show examples of the present invention, of which FIG. 1 is a sectional view taken along line I'-I in FIG. 7, and FIG. 2 is a sectional view taken along line u-n in FIG. 5. figure. Figure 3 is a side view of a motorcycle equipped with a two-stage carburetor, and Figure 4 is the same! L (a plan view of the body part; FIG. 5 is a front view of the two-stage carburetor; FIG. 6 is a sectional view taken along VI-VI in FIG. 5; FIG. 7 is a plan view of the two-stage carburetor). 2...Internal combustion engine, 3...Cylinder, 20...
・Variable venturi type carburetor part for low speed, 21.31...
...Venturi pipe, 22.32...Piston valve, 30...High-speed variable venturi type carburetor part, 3
4... Diaphragm 1 chamber, 35... Diaphragm, 40... Flow 1 ~ chambers. Figure 1 Figure 5 Figure 6

Claims (1)

[Claims] The high-speed variable bench lily type carburetor part automatically adjusts the passage area of the bench lily pipe by a piston valve that is slidably operated by a negative pressure responsive diaphragm housed in the diaphragm chamber, and the sliding operation is performed by forced operation from the outside. A low-speed variable bench lily type carburetor part whose passage area of the bench lily pipe is adjusted by a piston valve is installed in parallel, and the two bench lily pipes form a combustion chamber of an internal combustion engine. In a two-stage vaporizer adapted to be connected together to the mouth, the two
A two-stage carburetor characterized in that the positions of the two piston valves are arranged to be different from each other in the length direction of the vent lily tubes, and the vent lily tubes are brought close to each other.