JPH0216354A - Rotating throttle valve type carburettor - Google Patents

Abstract

PURPOSE:To hold the reproducibility of a fuel flow rate precisely by raising a regulating screw according to the normal rotation of a throttle body to push up a needle with a spring, and lowering the regulating screw according to the reverse rotation of the throttle body to push down the needle. CONSTITUTION:A throttle body 15 is rotated clockwise, its throttle valve part 15C opens an inlet passage 11 so that the intake amount is increased. A controlling protruded part 15P is made in contact with a cam part 18B according to the clockwise rotation of the throttle body 15 to raise a holder 18, so that a regulating screw 19 is raised. A needle 17 is then raised by a spring 21, and thus the opening to the fuel well port 15B of a fuel control port 13B in a fuel nozzle 13 is increased to increase the fuel amount. ON the other hand, when the throttle body 15 is rotated anti-clockwise, the inlet passage 11 is clogged by the reverse action, and the opening to the fuel control well 15B of the fuel control port 13B is reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a carburetor that controls the amount and concentration of air-fuel mixture supplied to an engine, and particularly relates to a so-called rotary throttle valve type carburetor in which a throttle valve rotates. It is related to vessels.

[Conventional technology]

The throttle valve of the carburetor is controlled by the driver's accelerator wire operation to adjust and control the amount and concentration of the air-fuel mixture supplied to the engine, and there are generally two types: a rotating type and a sliding type. Broadly classified.

The present invention relates to a rotary throttle valve type carburetor using a rotary throttle valve.
Publication No. 9 is known. According to this, the opening of the fuel control hole drilled in the fuel nozzle into the intake passage is controlled by a needle in response to the change in the empty percentage amount accompanying the rotation of the throttle valve, and for this purpose, the fuel nozzle A needle is inserted into the opening of the throttle valve, and as the throttle valve opens, the needle is urged upward in the figure by a spring to increase the opening of the fuel control hole into the intake passage, thereby sucking out fuel into the intake passage. The amount is increased in accordance with the increase in the amount of air.

The spring that biases the needle is compressed between the fuel nozzle and the needle.

[Problem to be solved by the invention]

This conventional rotary throttle valve type carburetor has the following problems.

The spring is compressed and arranged between the fuel nozzle and the needle, and if it bends to some extent and the outer periphery of the spring falls to the side, it will fall to the inner periphery of the guide hole of the throttle valve that accommodates the fuel nozzle and needle. There may be contact.

In this state, when the throttle valve is rotated, the throttle valve rotates and is moved upward and downward in the figure by a cam surface provided on the cover. According to the rotation of the throttle valve, the outer periphery of the spring receives rotational force, and when the spring falls down significantly and comes into strong contact with the guide hole of the throttle valve, the spring rotates around the outer periphery of the needle. . When the spring rotates in this way, the needle is pressed in an inclined state with respect to the longitudinal axis of the fuel nozzle.The reason why this inclination suppression state is not constant is that it is caused by the inner diameter of the fuel nozzle and the outer circumference of the needle. The gap is not constant because it is biased toward the engine side or toward the cleaner side. (The effective gap area does not change, but the location where the gap is formed differs.) If this gap is formed on the engine side, it will easily receive the negative pressure in the intake tract, so more fuel will come out. If a gap is formed on the cleaner side, it will be less likely to receive negative pressure in the intake tract, resulting in less fuel flowing out.

For these reasons, it has been difficult to accurately maintain the reproducibility of the fuel flow rate when the throttle valve is repeatedly operated.

[Failure to solve the problem]

The rotary throttle valve type carburetor of the present invention has been developed in view of the above-mentioned drawbacks, and an object thereof is to provide the above-mentioned carburetor with excellent fuel reproducibility when the throttle valve is repeatedly operated. In order to achieve this purpose, a throttle body that controls the amount of air flowing through the intake tract of the carburetor body and a fuel nozzle that is inserted into the fuel control passage of the fuel nozzle that can protrude into the intake tract, so that the throttle body controls the amount of air flowing through the intake tract. A needle for controlling the effective opening area of a fuel control hole formed in the fuel nozzle; and an adjusting screw arranged opposite to the needle for adjusting the effective opening area of the fuel control hole formed by the needle and the fuel control hole. This is a rotary throttle valve type carburetor in which a needle spring that presses a needle against an adjustment screw is installed in a fuel control passage of a fuel nozzle.

[Effect]

According to the rotary throttle valve type carburetor of the present invention, air is supplied to the engine through the gap formed by the throttle body, while fuel is supplied through the fuel control hole formed in the fuel nozzle. It is controlled and supplied by a needle.

In particular, even when the throttle body rotates, the fuel nozzle and needle do not rotate at all, so the gap formed by the inner diameter of the fuel nozzle and the outer diameter of the needle does not change with the rotation of the throttle body, but always. in a set fixed position.

〔Example〕

Hereinafter, one embodiment of the rotary throttle valve type carburetor according to the present invention will be described with reference to FIGS. 1 and 2.

10 is the carburetor main body through which the intake passage +1 passes;
A cylindrical throttle valve guide tube 12 is bored in the middle of the intake passage 11 . The lower side of this throttle valve guide cylinder 12 crosses the intake passage 11 and enters the carburetor body 10 from the bottom of the intake passage II, and the other side is opened from the upper side 11F81OA of the carburetor body 10.

Note that the upper part 10A of the carburetor main body 10 of the throttle valve guide cylinder 12
The opening side has a diameter larger than that of the throttle valve guide cylinder 12 in order to accommodate a throttle valve return spring, which will be described later.

A fuel nozzle 13 is disposed to protrude within the intake path ll at the bottom of the throttle valve guide cylinder 12, and a fuel control passage +3A is formed through the fuel nozzle 13 along the long axis of the seventh axis. The lower part thereof is connected to the fuel flow path 14 via the fuel control jet J.

Further, a fuel control hole 13B is bored in the fuel control passage 13A, and preferably a long groove extending along the longitudinal axis of the fuel control passage 13A. Therefore, the fuel flowing in the fuel flow path 14 is the fuel control jet J, the fuel control passage 13A, and the fuel control hole 13B.
The fuel flows out of the fuel nozzle X3.

In this embodiment, the fuel control hole 13B is opened toward the engine, but its opening position is determined as appropriate depending on the setting with the engine. Reference numeral 15 denotes a throttle body rotatably disposed in the throttle valve guide cylinder 12, and has the following configuration.

That is, 15A is a shaft portion which has a fuel well hole 15B surrounding the outer periphery of the fuel nozzle 13 with a gap S, and which opens at least into the intake passage 11. Plate-shaped throttle valve parts 15C and 15D that can control opening and closing of the passage 11 extend laterally. Further, cylindrical bearing parts 15E and 15F that are fitted into the throttle valve guide cylinder 12 are provided at both upper and lower ends of the shaft part 15A that does not open into the intake passage 11, and further, at the upper and lower ends of the shaft part 15A that does not open into the intake passage 11. is the fuel well 15B (fuel nozzle 13
A through hole 15 that communicates the gap S) on the outer periphery of the intake passage 11 with the air intake passage 11
G, 15H is drilled.

The number, diameter, and position of the through holes 15G and 15H are determined by the setting work with the engine.

Moreover, above the upper bearing part 15F and the carburetor main body 1
0 with a gap in the upper part 10A of the throttle valve lever part 15J.
is integrally provided, and furthermore, a part 15 is provided to this throttle valve.
For example, a cylindrical body 15K is integrally provided above J. An opening recess 15L is bored at the upper end of the cylinder 15, and a holder fitting hole 15M and a needle are formed from the bottom of the opening recess 15L in the direction of the longitudinal axis of the throttle body 15 and downwardly approximately on the center thereof. The needle fitting hole 15N is arranged in series, and the needle fitting hole 15N is positioned downward.
It penetrates into the fuel well 15B.

Furthermore, on the side of the opening of the holder fitting hole 15M to the opening recess 15L, that is, at the bottom of the opening recess 15L, a control protrusion 15F is provided that projects from the bottom. Also,
The cover 16 is arranged with gaps on the sides and above the cylinder 15 of the throttle body 15, specifically, the annular part 16A that surrounds the sides of the cylinder 15 and the upper part of the cylinder 15. The upper lid 1BB covers the upper lid 1BB, and a locking step 16F that projects into the opening recess 15L of the throttle body 15 is provided at the lower part of the upper lid 16B.

A needle 17 is movably arranged in the needle fitting hole 15N of the throttle body 15, and the lower part of the needle 17 is connected to the fuel control passage +3 of the fuel nozzle 13.
The fuel well 15B of the fuel control hole 13B is inserted into the fuel well A.
This is to control the opening area for the needle 17.
The upper part of is disposed facing the holder insertion hole 15M side.

Further, a holder 18 is inserted into the holder insertion hole 15M of the slot body 15, and a hole 18A is drilled from the top to the bottom inside the holder 18 at the longitudinal axis and center. On the other hand, a cam portion 18B is provided from the upper side of the holder 18, and this cam portion 18B
is in contact with the control protrusion 15F of the throttle body 15.

The cam portion 18B is provided radially from the center of the holder 18, and when the control protrusion 15F rotates about the center of the throttle body 15, the cam profile of the cam portion 18B causes the holder 18 to fit into the holder. Hole 1
It moves up and down within 5M.

Further, reference numeral 180 denotes a locking projection protruding from the holder 18, and this locking projection 18C is locked to the locking step 18F of the upper lid body 16. An adjusting screw 19 is screwed into the hole +8A of the holder 18, and the lower end of the adjusting screw 19 protrudes from the lower end of the holder 18 and comes into contact with the needle 17. Therefore, the fuel nozzle 13. Needle +7. Throttle body 15. Holder 18. and the longitudinal axis of the adjusting screw 19 are approximately the same.
placed in a straight line.

Further, reference numeral 20 denotes a holder spring, which is arranged approximately concentrically around the outer periphery of the adjustment screw 18. One end of the holder spring 20 is engaged with the cover 16, and the other end is engaged with the holder 18. Accordingly, the cam portion 18B of the holder 18 is connected to the control protrusion 15 of the throttle body 15.
At the same time, the locking protrusion 18C of the holder 18 is pressed against the locking step 1fliF of the cover 16.

Reference numeral 21 denotes a needle spring, which is contracted in the fuel control passage 13A of the fuel nozzle 13, one end of which is locked to the end of the needle 17 inserted into the fuel control passage 13A, and the other end of which is connected to the fuel control passage 13A. It is locked to the control jet J.

Therefore, the needle 17 is always urged upward by the spring force of the needle spring 21 and is held pressed against the lower end of the adjusting screw 19.
is pressed elastically against the bottom edge of the

In addition, 22 is a throttle valve return spring, which is arranged approximately concentrically around the outer periphery of the bearing portion 15F of the throttle body 15. One end of the throttle valve return spring 22 is locked to the throttle body 15, and the other end is locked to the throttle body 15. is secured to a stay plate 23 covering the upper side 10A of the carburetor main body 10, whereby the throttle body 15 is always biased with a force in the closing direction.

Next, its effect will be explained.

First, in order to increase the engine output from the idling state of the engine, the throttle body 15 is rotated clockwise in FIG.
The plate-shaped throttle valve parts 15c and 15D open the intake passage 11 and increase the amount of air flowing through the intake passage 11.

On the other hand, when the throttle body 15 is rotated clockwise, the control protrusion 15F comes into contact with the cam part 18B of the holder 18 and moves the holder 18 upward in the figure, and at this time the adjustment screw 19 also rotates. Holder 18
The needle 17 is moved upward by the spring force of the needle spring 21 and the moving force of the holder 18 and the adjustment screw 19, and the fuel control hole 13 is moved upward.
By increasing the opening to the fuel well hole 15B of B, the amount of fuel can be increased in proportion to the increase in the amount of air.

Next, we will discuss the transition from high-speed operation to low-speed operation of the engine when the throttle body 15 is opened to a high opening.
The throttle body 15 rotates counterclockwise in the figure, and is capable of closing the intake passage +1 with throttle valve portions 15C and 150 to reduce the amount of air.

On the other hand, the holder 18 moves downward in the figure due to the contact between the cam part 18B and the control protrusion 15P, and the adjustment screw 19 moves the needle 17 in the holder 18 against the spring force of the needle spring 21. By pressing in the molecular direction, the opening of the fuel control hole 13B to the fuel well 15B is reduced, thereby making it possible to reduce the amount of fuel commensurate with the reduction in the amount of air.

〔Effect of the invention〕

The rotary throttle valve type carburetor according to the present invention provides the following effects.

■When the throttle body rotates, the holder is prevented from rotating by the locking step of the cover, so the adjustment screw and needle do not rotate, and therefore the member that locks both ends of the needle spring, i.e. Since neither the needle nor the fuel control jet rotates, the needle spring is not subjected to any rotational force.

From the above, when the needle spring is compressed by the needle, the needle spring temporarily bends and comes into contact with one side of the fuel control passage of the fuel nozzle, exerting a force to bias the needle to one side. Even if given,
Since this biasing force does not change due to repeated rotations of the throttle body, the needle receives the biasing force and is located in the fuel control passage of the fuel nozzle, and the needle's outer diameter and fuel control are formed by falling down. The position of the gap with the inner diameter of the passage is formed at a constant position in the carburetor, such as the engine side or the cleaner side, so that a rotary throttle valve type carburetor with excellent reproducibility can be provided. It is.

■By arranging a needle spring inside the fuel control passage, the chamber volume inside the fuel control passage can be reduced. Since it was possible to increase the flow rate of the fuel flowing through the tube, it was possible to atomize the fuel and improve the negative pressure response.

[Brief explanation of the drawing]

The figures show an embodiment of a rotary throttle valve type carburetor according to the present invention.
It is a cross-sectional view taken along the I line. 10. Vaporizer main body 12. ,,, Throttle valve guide cylinder +3. ．． ．． ．． Fuel nozzle +3A, Fuel control passage 13B, Fuel control hole +5. , Throttle body +5A, Shaft 15F, Control protrusion 16, Cover 1? ,,, Needlemi 11. ．． ．． Holder IL, Adjustment screw J, Fuel control jet 2+, Needle spring 2

Claims (1)

[Scope of Claims] A throttle body that controls the amount of air flowing through an intake passage of a carburetor body; and a throttle body that is inserted into a fuel control passage of a fuel nozzle that can protrude into the intake passage, and according to rotation of the throttle body; a needle that controls the effective opening area of a fuel control hole formed in the fuel nozzle; an adjustment screw that is arranged opposite to the needle and adjusts the effective opening area of the fuel control hole formed by the needle and the fuel control hole; A rotary throttle valve type carburetor comprising a needle spring that presses a needle against an adjustment screw in a fuel control passage of a fuel nozzle.