JP3303183B2 - Sliding throttle valve carburetor - 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 controlling the concentration and amount of an air-fuel mixture supplied to an engine, in which a throttle valve is movable in a throttle valve guide cylinder provided in connection with an intake passage. The present invention relates to a sliding throttle valve carburetor which is arranged and a venturi area formed by an intake passage and a throttle valve is controlled by moving the throttle valve.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional sliding throttle valve carburetor.
This will be described below. Reference numeral 1 denotes a carburetor body in which an intake passage 2 is penetrated sideways, and a throttle valve guide cylinder 3 is continuously provided upward from an intermediate portion of the intake passage 2. Reference numeral 4 denotes a throttle valve movably arranged in the throttle valve guide cylinder 3, and a cutterway which forms an inclined surface from an air cleaner side end surface 4A of the throttle valve 4 to a bottom portion on the engine side (to the left in the drawing). 4B is formed. The cutterway 4B is provided to control a negative pressure applied to the nozzle 5 opening to the intake path 2. The opening and closing of the throttle valve 4 is controlled by the driver, so that the opening area of the venturi V formed by the intake path 2 and the bottom of the throttle valve 4 including the cutterway 4B is controlled, and the intake path 2A on the air cleaner side is controlled.
The amount of air flowing in from the air is controlled by a venturi section V, and is supplied to an engine (not shown) via an intake path 2B on the engine side. The nozzle 5 has an upstream end connected below a fixed fuel level formed in the float chamber 6 via a fuel jet 7 and a downstream end protruding and opening to the venturi V. The fuel is supplied according to the airflow flowing through the fuel cell.

[0003]

Looking at the intake path 2 of such a conventional sliding throttle valve type carburetor, the intake path is connected to an air cleaner (not shown but arranged on the right side of the figure). The intake path 2A on the air cleaner side and the throttle valve 4
And a suction path 2B on the engine side connected to the engine (not shown but arranged on the left side of the figure). Among them, paying particular attention to the intake path 2A on the air cleaner side, the intake path 2A on the air cleaner side has a venturi section V in order to enhance the venturi effect (throttle effect) in the venturi section V, and the intake path 2 on the engine side. The diameter is formed sufficiently larger than the diameter of 2B. Specifically, in the intake path 2A on the air cleaner side, the opening side to the air cleaner has a large diameter, and a middle portion has a reduced portion 2C whose diameter is greatly reduced and continues to the venturi portion V.

According to the above, the intake path 2 on the air cleaner side
The air flow flowing toward the venturi part V in A is
A turbulent flow is caused by a sharp decrease in the diameter of the reduced portion 2C in the intake path 2A on the air cleaner side. When the turbulent air flow and the air flow along the cutterway 4B of the throttle valve 4 flow into the venturi section V, the air flow flowing through the venturi section V becomes a complicated turbulent state. And
According to the above-described turbulence in the air flow flowing through the venturi portion V, the fuel sucked into the venturi portion V from the fuel nozzle 5 is not provided with a fixed direction and diffuses in all directions. . According to the above,
The fuel adheres to the inner wall of the intake passage 2 and the atomization of the fuel is hindered. It takes time for fuel to reach the engine from the carburetor. There was a problem that.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and improves the atomization of fuel sucked into an intake passage and the straightness of the atomized fuel toward the engine to improve the operation of the engine. It is an object of the present invention to provide a sliding throttle valve type carburetor capable of improving the performance and obtaining excellent transient response.

[0006]

According to the present invention, in order to achieve the above object, a throttle valve guide cylinder is connected to an intake passage penetrating a carburetor body, and the throttle valve guide cylinder is provided with an intake passage. In a sliding throttle valve type carburetor in which a throttle valve that opens and closes is movably disposed and a throttleway is formed on the throttle valve from the air cleaner side end surface to the engine-side bottom, an intake passage on the air cleaner side of the throttle valve is provided. In addition, the upstream end reaches the vicinity of the air cleaner side end of the intake passage, and the downstream end reaches the vicinity of the air cleaner side guide side of the throttle valve guide cylinder and forms a continuous flow surface facing the cutterway of the throttle valve. The first characteristic is that the width of the flow straightening wall in a plane orthogonal to the intake path is smaller than the width formed by the intersection of the cutterway and the intake path.

[0007] In addition, the present invention is characterized in that, in addition to the first feature, the width of at least the downstream end of the rectifying wall is substantially the same as the width of the nozzle that opens to the intake passage.

According to the present invention, in addition to the first feature, the height of the straightening wall protruding from the bottom of the intake passage at least at the downstream end is substantially the same as the height of the nozzle opening into the intake passage. Is a third feature.

[0009]

According to the first feature, the flow of air flowing from the air cleaner into the intake path of the carburetor flows along the straightening wall in the intake path on the air cleaner side. This rectification wall,
Since the air passage is formed as a continuous surface from the end on the air cleaner side of the intake passage to the vicinity of the guide side surface of the throttle valve guide cylinder on the air cleaner side, the air flow is rectified into a flow along the rectification wall. Then, the rectified air flows toward the cutterway of the throttle valve, so that the rectified air can be supplied to the venturi portion. Therefore, it is possible to rectify the airflow flowing through the venturi section into a flow flowing in one direction, and it is possible to supply fuel to the engine with directionality.

According to the second feature, the air flow rectified by the rectifying wall can be effectively directed toward the nozzle, and the intake air flowing through the venturi portion is not reduced.

According to the third feature, since the air flow rectified by the rectifying wall can be intensively supplied toward the tip of the nozzle, the directionality of the fuel sucked out of the nozzle is more constant. The direction can be determined, and it is suitable for the fuel to reach the vicinity of the engine in a short time.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a sliding throttle valve type carburetor according to the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view, and FIG. 2 is a right side view of FIG. Note that the same components as those in FIG. According to the present invention, a rectifying wall 9 in which a rectifying wall 9 is newly added to a conventional sliding throttle valve type carburetor will be described below. The rectifying wall 9 is provided on the intake path 2 on the air cleaner side.
A is formed at the bottom 2D of the intake passage 2A on the side where the nozzle 5 is open at A. The upstream end 9A of the rectification wall 9 (upstream,
Downstream in the direction of air flow) reaches the air cleaner side end 2E or the vicinity of the air cleaner side end 2E of the intake path 2A on the air cleaner side. Downstream end 9B of rectification wall 9
Is a guide side 3A of the throttle valve guide cylinder 3 on the air cleaner side.
Reaches the vicinity of. In other words, the downstream end 9B reaches the vicinity of the air cleaner side end surface 4A of the throttle valve 4.
The downstream end 9B and the upstream end 9A of the flow regulating wall 9 are connected by a continuous surface 9C, and the continuous surface 9C is formed toward the cutterway 4B of the throttle valve 4. Further, the width D of the rectifying wall 9 in a plane orthogonal to the intake path 2
Is formed to be smaller than the width D1 formed by the point AA where the cutterway 4B of the throttle valve 4 and the intake path 2 intersect. The width D of the rectifying wall 9 is well shown in FIG.

According to the sliding throttle valve carburetor according to the present invention, the air flow particularly toward the nozzle 5 opening into the venturi portion V is mainly the air flow flowing through the cutterway 4B of the throttle valve 4. Then, the airflow flowing through the continuous surface 9C of the flow regulating wall 9 is directed. Here, looking at the airflow flowing through the cutterway 4B, the cutaway 4B is formed by a continuous surface, and is rectified into a flow directed in a certain direction along the longitudinal axis of the intake path 2. Therefore, the air flow in the rectified state flows into the venturi portion V.

On the other hand, looking at the flow of air flowing through the rectifying wall 9, the continuous surface 9C of the rectifying wall 9 is formed continuously with a certain length from the upstream end 9A to the downstream end 9B. Thus, the airflow is rectified into air flowing in a certain direction along the longitudinal axis of the intake path 2. Then, the air flow in the rectified state flows into the venturi portion V.

As described above, according to the fact that the air flows, which have slightly different flow directions but are in a rectified state, respectively, flow into the nozzle 5 opened to the venturi portion V,
Around the nozzle 5 of the venturi portion V, an air flow in a rectified state going downstream is formed, and the nozzle 5 is in a rectified state flowing in a certain direction along the longitudinal axis of the intake passage 2. Located in the air stream.

According to the above, well atomized fuel is sucked out from the nozzle 5 to the venturi portion V. On the other hand, the atomized fuel is dispersed in the intake passage 2 in all directions. Without being mixed, the air is mixed into the airflow in a certain direction along the longitudinal axis of the intake passage 2 and supplied to the engine from the intake passage 2B on the engine side. The atomized fuel sucked out from the nozzle 5 adheres to the inner peripheral wall of the intake passage 2 and does not condense the fuel again and hinder atomization. The fuel thus supplied can be supplied to the engine, and a good combustion state of the engine can be obtained, thereby greatly improving the operability of the engine and the reduction of harmful exhaust gas.

Looking at the air flow in the venturi section, the flow is regulated in a certain direction along the longitudinal axis of the intake passage 2 by the cutterway 4B of the throttle valve 4 and the continuous surface 9C of the rectifying wall 9. According to the result, the atomized fuel was mixed into the straight air flow, and the throttle valve 4 was opened. For example, during the acceleration operation of the engine, the fuel was immediately discharged without delay. Since it can be supplied to the engine, the transient response performance of the engine can be greatly improved.

The width D of the rectifying wall 9 is determined by the width D formed by the point A-A where the cutterway 4B and the intake passage 2 meet.
The fact that it is smaller than 1 is, in cooperation with the cutterway 4B,
This is necessary for effectively forming an air flow in a certain direction in the venturi portion V. Also, the downstream end 9 of the rectifying wall 9
B 'may be used as the bottom of the venturi portion V, and the continuous surface 9C' of the rectifying wall 9 is shown by a two-dot chain line in FIG. Further, the downstream end 9B "of the flow regulating wall 9 may be provided at a position higher than the cutterway 4B when the throttle valve 4 is at the minimum opening degree. Achieve the continuous surface 9 of the rectifying wall 9
1 indicates that the downstream end 9B of the rectifying wall 9 is directed toward the cutterway 4B of the throttle valve 4 by directly opening the cutterway 4B when the throttle valve 4 is at the minimum opening degree. It is not limited to.

The width D of the rectifying wall 9 at least at the downstream end 9B is made substantially the same as the width D2 of the nozzle 5 opening into the intake passage 2, so that the air flow flowing through the venturi V is directed to the nozzle 5. It is possible to effectively direct the vehicle toward the engine, and it is possible to suppress a decrease in the output of the engine without reducing the intake efficiency flowing through the intake passage 2. Regarding the width of the rectifying wall 9 (for example, the upstream end 9A) other than the downstream end 9B, the rectifying wall has a sufficiently large area as compared with the venturi portion V and the intake passage 2B on the engine side. Since it is arranged on the road 2A, the intake efficiency is not reduced even if D> D2.

Furthermore, at least the downstream end 9B of the rectifying wall 9
Of the intake passage 2 from the bottom of the intake passage 2
When the height is substantially the same as the protruding height H1 of the nozzle 5 that opens to the opening, the air flow rectified by the continuous surface 9C of the rectifying wall 9 can be made to effectively act on the opening of the nozzle 5. According to this, it is effective to improve the atomization of the fuel and to increase the response speed of the fuel.

[0021]

As described above, according to the sliding throttle valve type carburetor according to the present invention, the rectifying wall having the continuous surface facing the cutterway is provided in the intake passage on the air cleaner side from the throttle valve, so that the fuel Therefore, the operability of the engine and the removal of harmful exhaust gas components can be effectively performed. In addition, according to the fact that the width at the downstream end of the rectifying wall is made substantially the same as the width of the nozzle, a decrease in suction efficiency is suppressed in addition to the above-described effects. Furthermore, according to the fact that the protruding height at the downstream end of the rectifying wall is substantially the same as the protruding height of the nozzle that opens to the intake passage, the air flow that is in a rectifying state more concentrated toward the nozzle opening acts. As a result, the transient response was further improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a sliding throttle valve type carburetor according to the present invention.

FIG. 2 is a right side view in FIG.

FIG. 3 is a longitudinal sectional view of a conventional sliding throttle valve type carburetor.

[Explanation of symbols]

 2 Intake path 2A Intake path on air cleaner side 2B Intake path on engine side V Venturi section 3 Throttle valve guide cylinder 3A Guide side of throttle valve guide cylinder on air cleaner side 4 Throttle valve 4A Air cleaner side end face of throttle valve 4B Cutterway 5 Nozzle 9 Rectification Wall 9A Downstream end of rectification wall 9B Upstream end of rectification wall 9C Continuous surface

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-15659 (JP, A) JP-A-58-178857 (JP, A) JP-A-58-113564 (JP, A) 26233 (JP, U) JP-A 61-144247 (JP, U) Japanese Patent Publication No. 4-5821 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02M 9/06 F02M 7 / 16 F02M 19/00

Claims (3)

(57) [Claims] A throttle valve guide cylinder is connected to an intake passage penetrating the carburetor body, and a throttle valve for opening and closing the intake passage is movably disposed in the throttle valve guide cylinder. In a sliding throttle valve type carburetor in which a cutterway is formed from the end face on the air cleaner side to the bottom on the engine side, an upstream end 9A is connected to an intake passage 2A on the air cleaner side from the throttle valve 4.
Reaches the vicinity of the air cleaner side end 2E of the intake passage 2,
The downstream end 9B reaches the vicinity of the guide side surface 3A on the air cleaner side of the throttle valve guide cylinder 3 and forms a rectifying wall 9 that forms a continuous surface 9C facing the cutterway 4B of the throttle valve 4,
A sliding throttle valve type, characterized in that a width D of the rectifying wall in a plane orthogonal to the intake path 2 is smaller than a width D1 formed by a point A-A where the cutterway 4B and the intake path 2 intersect. Vaporizer. 2. The sliding throttle valve type according to claim 1, wherein a width D of said rectifying wall at least at a downstream end 9B is substantially equal to a width D2 of a nozzle 5 opening into the intake passage 2. Vaporizer. 3. A height H of at least the downstream end 9B of the straightening wall protruding from the bottom of the intake passage 2 is substantially equal to a height H1 of the nozzle 5 opening into the intake passage 2. A sliding throttle valve type carburetor according to claim 1.