JPH0749000Y2 - Horizontal variable venturi vaporizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] In the present invention, a main intake passage having a butterfly throttle valve is horizontally arranged, and intake air in the main intake passage is provided upstream of the butterfly throttle valve. The present invention relates to an improvement of a horizontal variable venturi carburetor in which a sliding valve that forms a variable venturi by crossing and reciprocating with the main intake passage depending on a flow rate is arranged, and a main fuel nozzle is arranged in the venturi portion. The present invention relates to a horizontal variable venturi carburetor capable of reducing uneven distribution of fuel to each cylinder of an engine having a plurality of cylinders to which a venturi carburetor is attached at high load and low speed rotation.

[Prior Art] In a horizontal variable venturi carburetor, the fuel flowing out from the main fuel nozzle opening to the variable venturi portion is not atomized in the main intake passage when the engine rotates at high load and low speed, as shown in FIG. It flows down to the lowest position on the wall surface and flows toward the downstream side of intake air along the inner wall surface of the main intake passage,
Since it flows into each cylinder of the engine in a liquid state even after flowing into the intake manifold of the engine, the fuel flow rate distributed to each cylinder tends to be non-uniform.

In the vaporizer in which the power nozzle is arranged in the variable venturi portion, the same applies to the fuel flowing out from the power nozzle. In FIG. 3, a is the main intake passage, b is the butterfly throttle valve, c is the sliding valve, d is the main fuel nozzle, e is the power nozzle, and f is the fuel flowing down.

The degree to which fuel is distributed unevenly depends on the shape of the branch portion of the intake manifold and the intake order (ignition order). (In a carburetor in which the main intake passage is arranged vertically, the engine cooling water or exhaust gas circulates in the lower horizontal part even if it flows down the main intake passage and the vertical part of the engine intake manifold without atomizing the fuel. A heating riser is installed, and the fuel is vaporized and supplied to each cylinder in a gaseous state, so that there is no significant fuel distribution imbalance to each cylinder.)
As a measure to reduce the fuel distribution imbalance in the horizontal variable venturi carburetor, as shown in FIGS. 4, 5, and 6, the shape of the lower end surface of the sliding valve is asymmetrical in the intake air flow direction. However, there is a problem that even if the deviation of the fuel distribution at the low speed rotation is improved, the deviation at the high speed rotation becomes rather large.

4 and 5 are views of the sliding valve as seen from the upstream side of the main intake passage. The reference numerals in the drawings show the same contents as the reference numerals in FIG. 3, and g indicates the bottom of the sliding valve c. The part where the end face is fleshed,
h indicates a portion where the meat is removed, and the broken line is a line showing the symmetrical lower end surface shape of the sliding valve c.

FIG. 6 is a view of the lower end surface of the sliding valve, in which a is the main intake passage and c is the sliding valve as in the case of FIG. 3, and i is the sliding valve c. This is a groove formed on the lower end surface, in which the direction of the groove i is changed in the middle to change the intake flow direction to correct the deviation of the fuel.

7 and 8 show the structure of the constant negative pressure type carburetor (variable venturi carburetor) disclosed in Japanese Utility Model Publication No. 4-4963, in which a is the main intake passage, b is the butterfly throttle valve, and c is the sliding valve. A valve, d is a main fuel nozzle, and a fixed small venturi j having a small diameter is formed in contact with the lowest position of the inner wall surface of the main intake passage a, and the main fuel nozzle d is opened in the fixed small venturi j. The sliding valve c has an inverted U-shaped recess for holding the fixed small venturi j upward from the lower end surface, and the butterfly throttle valve b has a small intake flow rate with a small opening. At this time, a high intake flow velocity is formed in the fixed small venturi j in order to obtain good atomization of the fuel, but at the time of high load low speed rotation, the fuel flowing out from the main fuel nozzle d is fixed small. After hitting the upper surface of the inner wall of the venturi d, it flows down to the lowest position of the inner wall, or After flowing out from d, it directly flows down to the lowest position of the inner wall surface of the fixed small venturi j, and the fuel flows into the intake manifold of the engine in a liquid state without being atomized. Therefore, there is a tendency of uneven distribution of fuel to each cylinder. It will not be resolved.

[Problems to be Solved by the Invention] When the engine is rotating under a high load and at a low speed, the fuel that has flowed out without being atomized from the main fuel nozzle has flowed out without being atomized from the power nozzle if the power nozzle is included. It is an object of the present invention to obtain a horizontal variable venturi carburetor that forms an air flow that grinds fuel together with the fuel toward the downstream side of the main intake passage along the lowest position of the inner wall surface of the main intake passage. is there.

[Means for Solving the Problem] The main intake passage provided with a butterfly throttle valve is horizontally arranged,
A slide valve is disposed upstream of the butterfly throttle valve, which slides back and forth with the main intake passage to form a variable venturi depending on an intake flow rate in the main intake passage, and a sliding valve is provided in the variable venturi portion. In a horizontal variable venturi carburetor in which a fuel nozzle is arranged, a lower portion of the variable venturi is divided by a wall body having a flat upper surface, and the main fuel nozzle is opened above the wall body. To do.

[Operation] The fuel flowing out from the main fuel nozzle, and if there is a power nozzle, the fuel flowing out from the power nozzle also flows down to the upper surface of the wall that divides the lower part of the variable venturi portion, and flows toward the downstream side of the main intake passage. When flowing down from the downstream edge of the wall onto the inner wall surface of the main intake passage, it is pulverized and atomized by the intake airflow flowing in the lower part of the divided variable venturi part, and the intake air of the engine is taken along the intake airflow. Since it flows into the manifold and is distributed and supplied to each cylinder of the engine, it is possible to reduce the uneven distribution as compared with the case of wetting the inner wall surface of the intake manifold and flowing into each cylinder along the inner wall surface.

[Embodiment] FIG. 1 is a longitudinal sectional view of an embodiment of a horizontal variable Venturi vaporizer of the present invention, showing a case having a power nozzle. FIG. 2 is a sectional view taken along the line II-II of FIG. In FIGS. 1 and 2, reference numeral 1 is a main intake passage, 2
Is a butterfly throttle valve, 3 is a slide valve that forms a variable venturi by moving forward and backward with the main intake passage 1 depending on the flow rate of intake air in the main intake passage 1, 4 is a main fuel nozzle, 5 is power The nozzle 6 is a wall that divides the lower part of the variable venturi portion of the main intake passage 1, and the upper surface of the wall 6 is formed flat. Reference numeral 7 denotes a variable venturi lower portion divided by the wall body 6. The main fuel nozzle 4 and the power nozzle 5 are opened on the wall body 6.

Although not directly related to the present invention, 8 is a choke valve and 9 is a float chamber.

The fuel flowing out from the main fuel nozzle 4 and the power nozzle 5 flows down to the upper surface of the wall body 6 and becomes a flow indicated by reference numeral 10 and the wall body 6
Is pushed toward the downstream side by the intake air flow and flows down from the downstream edge of the wall body 6 onto the inner wall surface of the main intake passage 1, but at this time, the lower part 7 of the divided variable venturi is divided.
Is pulverized by the intake air flow indicated by the arrow 11, and thereafter is distributed and supplied to each cylinder through the intake manifold of the engine along the intake air flow.

[Advantage of the Invention] The horizontal variable venturi carburetor of the present invention is a fuel that flows out from the main fuel nozzle at the time of high load and low speed rotation of the engine,
In the case of having a power nozzle, the fuel flowing out from the power nozzle is not atomized and the fuel flowing out does not immediately flow to the inner wall surface of the main intake passage, and the lower part of the main intake passage portion forming the variable venturi is Since it first flows down to the upper surface of the dividing wall body and then flows down onto the inner wall surface of the main intake passage, it is given an opportunity to be crushed by the intake airflow flowing through the lower part of the variable venturi that has been divided, and thereafter the intake airflow is changed. Therefore, there is an advantage that the fuel is supplied to the engine and the deviation of the fuel distribution among the cylinders can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a horizontal variable venturi vaporizer of the present invention, FIG. 2 is a sectional view taken along the line II--II of FIG. 1, and FIG. Fig. 4, Fig. 4 showing the flow of fuel at low load rotation,
FIGS. 5 and 6 are views showing a configuration which has been conventionally attempted in a horizontal variable venturi carburetor in order to reduce the deviation of the fuel distribution among the cylinders, and FIG. 7 is a view when the throttle valve is at a small opening with a small intake flow rate. FIG. 8 is a vertical sectional view showing the configuration disclosed in Japanese Utility Model Publication No. 4-4963 proposed for obtaining good atomization of fuel, and FIG. 8 is a sectional view taken in the direction perpendicular to FIG. Explanation of reference numerals: 1 ... Main intake passage, 2 ... Butterfly throttle valve, 3 ... Sliding valve, 4 ... Main fuel nozzle, 5 ... Power nozzle, 6 ... Wall body, 7 ... Variable venturi lower part divided by wall body Portions, 8 ... Choke valve, 9 ... Float chamber, 10 ... Flow of fuel on the wall at the time of high load and low speed rotation, 11 ... Arrows showing the intake flow of the lower part of the variable venturi divided by the wall.

Continuation of the front page (56) Bibliography Sho 52-81524 (JP, U) Shokoku 47-21010 (JP, Y1)

Claims (1)

[Scope of utility model registration request] 1. A main intake passage (1) provided with a butterfly throttle valve (2) is arranged in a horizontal direction, and the main intake passage (1) is provided upstream of the butterfly throttle valve (2) in the main intake passage (1). A sliding valve (3) is arranged which crosses and reciprocates with the main intake passage (1) to form a variable venturi depending on the intake flow rate, and a main fuel nozzle (4) is arranged in the variable venturi portion. In a horizontal variable venturi carburetor, a lower portion of the variable venturi is divided by a wall body (6) having a flat upper surface, and the main fuel nozzle (4) is opened above the wall body (6). A horizontal variable venturi carburetor characterized in that