JPH1054303A - Slide throttle valve type carburetor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve idling operation performance of an engine and operation performance in an intermediate opening region, by continuously drafting low speed fuel and effectively atomizing it from the lowest idling opening of a slide throttle valve to the intermediate opening region including an off idling opening. SOLUTION: In a bottom part 2 of a slide throttle valve, a straightening groove 3 is hollowly provided, which opens an upstream end 3A with a large groove width to a side surface 1A in an air cleaner side and connects a downstream end 3B with a small groove width to in the vicinity of a bottom part 1C of a side surface 1B in an engine side. The bottom part 1C of the side surface 1B in an engine side of the slide throttle valve is moved to an air cleaner side A in accordance with an opening of the slide throttle valve, so as to increase a distance between a bypass hole and the bottom part 1C of the side surface in the engine side of the slide throttle valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carburetor for adjusting and controlling the concentration and amount of an air-fuel mixture supplied to an engine, and more particularly to a throttle valve guide cylinder connected to an intake passage passing through a carburetor body. A sliding throttle valve is movably arranged in the inside, and the intake passage is controlled to be opened and closed by the sliding throttle valve, and a bypass hole for the low-speed fuel system opens near the bottom of the engine-side side surface of the sliding throttle valve. The present invention relates to a sliding throttle valve type carburetor.

[0002]

2. Description of the Related Art In a conventional sliding throttle valve type carburetor, an intake passage penetrates a carburetor body and a throttle valve guide cylinder is formed from an intermediate portion of the intake passage at right angles to the intake passage. A sliding throttle valve is movably arranged in the guide cylinder. On the other hand, a needle jet as a main fuel system, and a bypass hole and a pilot outlet hole as a low-speed fuel system are opened in the intake passage. The bypass hole is opened facing the bottom of the engine-side side surface of the sliding throttle valve.

[0003]

According to the conventional sliding throttle valve type carburetor, the positional relationship between the bypass hole and the bottom of the sliding throttle valve on the engine side is limited to the full opening range of the sliding throttle valve. Is in a constant state. According to the above description, when the sliding throttle valve is at the minimum idling opening, the opening is very small, so that a high negative pressure can be applied to the bypass hole, and the The low-speed fuel atomized from the holes can be sucked out of the sliding throttle valve into the intake passage on the engine side. However, in an off-idling opening range where the sliding throttle valve is further opened from the idling opening degree and in an intermediate opening range higher than that, the sliding throttle valve in which a high negative pressure occurs is located in the intake passage closer to the engine than the sliding throttle valve. It is difficult to apply a high negative pressure to the bypass hole since the bypass hole cannot be opened at the same time. According to the above, the atomization of the low-speed fuel sucked from the bypass hole may be hindered above the off-idling opening range, and furthermore, the low-speed fuel may be continuously supplied to the intermediate opening range above the off-idling opening range. It was difficult to evacuate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has been developed in consideration of the above problem. It is an object of the present invention to provide a sliding throttle valve type carburetor capable of improving fuel atomization and continuously supplying low-speed fuel from an idling opening to an intermediate opening range.

[0005]

In order to achieve the above object, a sliding throttle valve type carburetor according to the present invention slides in a throttle valve guide cylinder connected to an intake passage penetrating a carburetor body. The throttle valve is movably disposed, the intake passage is controlled to be opened and closed by the slide throttle valve, and the low-speed fuel system bypass hole opens near the bottom of the engine side surface of the slide throttle valve. In the type carburetor, the sliding throttle valve slides from the bottom of the air cleaner side formed on the air cleaner side of the longitudinal axis, the engine side formed on the engine side, and the bottom of the engine side. A bottom portion facing the air cleaner side located at an upper position with respect to the longitudinal axis of the throttle valve, and a recess formed in the bottom, an upstream end opening with a large groove width on the air cleaner side, and a downstream end facing the engine; Commutation with a small groove width near the bottom of the With the door, the sliding throttle valve, when opening the intake passage, the bottom portion of the engine side of the side surface of the sliding throttle valve,
The sliding throttle valve is moved to the air cleaner side in accordance with the degree of opening of the sliding throttle valve, and the distance between the bypass hole and the bottom of the side of the sliding throttle valve on the engine side is increased.

[0006]

At the bottom of the sliding throttle valve, air flows from the side of the sliding throttle valve on the air cleaner side to the side of the engine side, and the air flowing through the bottom is rectified by the rectifying groove and the rectified air Is converged toward the bottom of the engine-side side surface of the sliding throttle valve. According to the above, the negative pressure of the bypass hole opened near the bottom of the engine-side side surface of the sliding throttle valve can be increased, so that the low-speed fuel at the idling opening of the sliding throttle valve can be finely atomized. Also, when the sliding throttle valve is opened from the idling opening degree, the bottom of the engine side surface of the sliding throttle valve moves to the air cleaner side in accordance with the opening of the sliding throttle valve, and the bypass hole is The sliding throttle valve opens from the engine-side side surface to the engine-side intake passage. According to the above, a high negative pressure generated in the intake passage on the engine side from the sliding throttle valve can be applied to the bypass hole, so that the low-speed fuel sucked from the bypass hole can be effectively atomized and turned off. Low-speed fuel can be continuously sucked up to the intermediate opening range including the idling opening range.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sliding throttle valve type carburetor according to the present invention will be described below. FIG. 1 is a longitudinal sectional view of a sliding throttle valve used in the sliding throttle valve type carburetor of the present invention, and shows a state where its longitudinal axis XX is arranged in a vertical direction. FIG. 2 is a right side view of FIG. 1, and FIG. 3 is a lower plan view of FIG. The sliding throttle valve 1 will be described. Sliding throttle valve 1
Has a cylindrical shape, a side surface 1A of the air cleaner side is formed on the air cleaner side A (right side in FIG. 1) of the longitudinal axis XX, and the engine side B (FIG. 1) of the longitudinal axis XX. , A left side 1B on the engine side is formed. A bottom portion 2 is formed below the sliding throttle valve 1 in FIG. 1, and the bottom portion 2 extends from a bottom portion 1 </ b> C of an engine-side side surface 1 </ b> B of the sliding throttle valve 1 in a longitudinal axis XX direction. It is formed toward the side surface 1A on the air cleaner side at the upper position. That is, the bottom 2 has an upper right slope in FIG.

Reference numeral 3 denotes a rectifying groove formed in the bottom 2 of the sliding throttle valve 1. The upstream end 3A of the rectifying groove 3 opens to the side surface 1A on the air cleaner side with a large groove width D, and the downstream end 3B.
Is a small groove width E near the bottom 1C of the engine side surface 1B.
Connect with. That is, the flow regulating groove 3 extends from the side surface 1A on the air cleaner side to the vicinity of the bottom 1C of the side surface 1B on the engine side.

Reference numeral 4 denotes a jet needle insertion hole, which is formed along the longitudinal axis XX of the sliding throttle valve 1, and whose upper end is open to the inner bottom 1D of the sliding throttle valve 1 and which is lower. The end opens into the bottom 2. Reference numeral 5 denotes a rotation preventing groove,
And is formed along the longitudinal axis XX of the sliding throttle valve 1.

As described above, when the bottom portion 2 is located below the sliding throttle valve 1 and the longitudinal axis XX of the sliding throttle valve 1 is arranged in the vertical direction, the air cleaner is moved from the side surface 1B on the engine side. An upper right inclined surface is formed toward the side surface 1A. On the other hand, the rectifying groove 3 is recessed in the bottom 2, and its upstream end 3 A opens to the side 1 A of the sliding throttle valve 1 on the air cleaner side with a large groove width D, and the downstream end 3 B is the bottom of the side 1 B on the engine side. It reaches near 1C with a small groove width E. That is, the rectifying groove 3 recessed in the bottom 2 of the sliding throttle valve 1 extends from the upstream end 3A opening to the side 1A on the air cleaner side to the downstream end 3B reaching near the bottom 1C of the side 1B on the engine side. The width is gradually reduced.

The carburetor body 6 has an intake passage 7 penetrating therethrough and a throttle valve guide cylinder 8 inclined from the middle of the intake passage 7 to the air cleaner A side. That is, the throttle valve guide cylinder 8 is inclined upward and to the right in FIG.

M is a main fuel system, and a needle jet 9 arranged at the downstream end opens into the intake passage 7. The needle jet 9 has the main fuel controlled by the main fuel jet 10, The main air controlled by the main air jet 11 is mixed in the mixing pipe 12, and the main fuel is supplied. The needle jet 9 is arranged on the longitudinal axis of the throttle valve guide cylinder 8.

S denotes a low-speed fuel system. A bypass hole 13 and a pilot outlet hole 14 are opened in the intake passage 7, and the low-speed fuel controlled by the low-speed fuel jet 15 and the low-speed fuel (not shown) The low-speed air controlled by the air jet is mixed by the low-speed mixing pipe 16 and the low-speed fuel is supplied. The bypass hole 13
Opens in the intake path 7 on the air cleaner side A slightly from an extension of the engine side guide cylinder surface 8A of the throttle valve guide cylinder 8, and the pilot outlet hole 14 opens in the intake path 7 on the engine side B from the bypass hole 13. . Reference numeral 17 denotes a float chamber main body disposed below the vaporizer main body 1, and a float chamber 18 is formed by the vaporizer main body 1 and the float chamber main body 17, and a float chamber 18 is provided.
Inside, a constant fuel level is formed by the cooperative action of the float 19 and the like. The main fuel jet 10 and the low-speed fuel jet 15 are arranged below the fuel level.

The sliding throttle valve 1 is movably disposed in a throttle valve guide cylinder 8 of the carburetor body 1. According to this, the bottom 2 of the sliding throttle valve 1 and the rectifying groove 3 are arranged facing the intake passage 7, and the side 1A of the sliding throttle valve 1 on the air cleaner side is connected to the air cleaner side A (rightward in FIG. 4). ), And the engine side surface 1B is arranged facing the engine side B (left side in FIG. 4). The intake passage 7 is moved by the sliding throttle valve 1 to the intake passage 7A on the right side of the air cleaner.
And an engine-side intake passage 7B on the left.

A jet needle 20 is integrally mounted in the jet needle insertion hole 4 of the sliding throttle valve 1, and a tip portion of the jet needle 20 is inserted into a needle jet 9 opened to the intake passage 7. Placed.
The bypass hole 13 has a side surface 1 of the sliding throttle valve 1 on the engine side.
The bottom 1C of B is disposed to face, and the pilot outlet hole 14 opens from the bypass hole 13 to the intake passage 7B on the engine side. Reference numeral 21 denotes a cover for closing the upper opening of the throttle valve guide cylinder 8.
A spring 22 is contracted between the inner bottom 1D and the inner bottom 1D.
The throttle valve guide 2 protruding from the throttle valve guide cylinder 8 is provided.
Numeral 3 is inserted into the rotation preventing groove 5 of the sliding throttle valve 1, whereby the rotation of the sliding throttle valve 1 is suppressed.

Next, the operation will be described. FIG. 4 shows the minimum idling state of the sliding throttle valve 1.
This is a state where the sliding throttle valve 1 narrows the intake path 7 most, and the air flow from the intake path 7A on the air cleaner side to the intake path 7B on the engine side flows through the bottom 2 of the sliding throttle valve 1 and the rectifying groove. 2, the amount of air is controlled and determined by a small gap H formed by the bottom 1C of the engine side surface 1B of the sliding throttle valve 1 and the intake passage 7. The air flow heading for the minute gap H is converged and flows particularly along the flow straightening groove 2 and the gap is small, so that the air flow rate is effectively advanced. It is obtained. On the other hand, the bypass hole 13 opens toward the bottom 1C of the engine side surface 1B of the sliding throttle valve 1 and opens into the minute gap H. According to this, a high negative pressure acts on the bypass hole 13, Extremely atomized fuel can be sucked into the intake passage 7B on the engine side, and the idling operation of the engine can be favorably performed. The description of the suction of fuel from the pilot outlet hole 14 and the needle jet 9 will be omitted.

Next, a description will be given of an operation at the time of the off-idling opening in which the sliding throttle valve 1 is slightly opened from the minimum idling opening. When the sliding throttle valve 1 is opened, the sliding throttle valve 1 moves obliquely rightward and upward along the throttle valve guide cylinder 8, and the bottom 1C of the engine side surface 1B at the off-idling opening is , Shown in dotted lines in FIG. Here, it should be noted that the bottom 1C of the engine side surface 1B of the sliding throttle valve 1 moves to the air cleaner A side (the right side in FIG. 4), and the bypass hole 13 forms the engine side surface 1B. This is to open the intake passage 7B on the engine side from the bottom 1C. That is, the sliding throttle valve 1
The bottom portion 1C of the engine side surface 1B moves from the bypass hole 13 to the air cleaner side A by L1. According to the above,
First, the air flow from the side surface 1A on the air cleaner side of the sliding throttle valve 1 to the side surface 1B on the engine side goes from the large groove width D at the upstream end 3A to the small groove width E at the downstream end 3B, The air flow is rectified by the rectifying groove 3 and converges toward the bottom 1C to flow down. This air flow reaches the bottom 1C of the engine side surface 1B of the sliding throttle valve 1. according to this,
The air flow velocity near the bottom 1C of the engine side surface 1B of the sliding throttle valve 1 is greatly increased, and the negative pressure in this portion can be increased. Secondly, the bypass hole 13 opens into the engine-side intake passage 7B from the engine-side side surface 1B of the sliding throttle valve 1, and a negative pressure in the engine-side intake passage 7B in a high negative pressure state. Pressure can be applied to the bypass hole 13. According to the first and second points, since a high negative pressure can be applied to the bypass hole 13, the appropriate low-speed fuel corresponding to the off-idling opening of the sliding throttle valve 1 is extremely atomized. In this state, it can be sucked into the intake path 7B on the engine side,
A good engine off-idling state can be obtained.

Next, the operation in the intermediate opening range where the sliding throttle valve 1 is further opened from the off-idling opening will be described. When the sliding throttle valve 1 is opened, the sliding throttle valve 1 moves further obliquely rightward and upward along the throttle valve guide tube 8, and the engine side surface 1B at this intermediate opening degree
Is indicated by a dashed line in FIG. In this state, the bottom 1C of the engine side surface 1B of the sliding throttle valve 1 further moves to the air cleaner A side (the right side in FIG. 4).
The bypass hole 13 opens from the bottom 1C of the side surface 1B on the engine side to the intake passage 7B on the engine side. That is, the bottom 1C of the engine side surface 1B of the sliding throttle valve 1 moves from the bypass hole 13 to the air cleaner side A by L2. According to the above description, first, the air flow from the side surface 1A on the air cleaner side of the sliding throttle valve 1 to the side surface 1B on the engine side has a large groove width D at the upstream end 3A and a small groove width at the downstream end 3B. Toward E, the air is rectified by the rectifying groove 3 and converges toward the bottom 1C and flows down. This air flow reaches the bottom 1C of the engine side surface 1B of the sliding throttle valve 1. According to this, the air flow velocity near the bottom 1C of the engine side surface 1B of the sliding throttle valve 1 is greatly increased, and the negative pressure in this portion can be increased. Secondly, the bypass hole 13 opens into the engine-side intake passage 7B from the engine-side side surface 1B of the sliding throttle valve 1, and a negative pressure in the engine-side intake passage 7B in a high negative pressure state. Pressure can be applied to the bypass hole 13. According to the above first and second points, since a high negative pressure could be applied to the bypass hole 13, the appropriate low-speed fuel corresponding to the intermediate opening of the sliding throttle valve 1 was extremely atomized. In this state, air can be sucked into the intake passage 7B on the engine side, and a favorable intermediate opening degree operating state of the engine can be obtained.

As described above, when the sliding throttle valve 1 is at the minimum idling opening, the negative pressure acting on the bypass hole 13 can be increased by the rectifying groove 3 formed in the bottom 2 of the sliding throttle valve 1. Therefore, the low-speed fuel can be atomized, and the good engine idling operation can be performed. In addition, during the off-idling operation and the intermediate opening operation of the engine in which the sliding throttle valve 1 is opened further than the idling opening, the negative pressure acting on the bypass hole 13 can be increased by the rectifying groove 3. At the same time, a high negative pressure in the intake passage 7B on the engine side from the sliding throttle valve 1 can be applied to the bypass hole 13, so that the low-speed fuel can be atomized well and the appropriate amount corresponding to the opening of the sliding throttle valve 1 As a result, a good fuel can be sucked into the intake passage 7B on the engine side, so that a good off-idling operation and an intermediate opening degree operation of the engine can be obtained.

The sliding throttle valve 1 in this embodiment has a circular cross-sectional shape, but may have a short shape or an elliptical shape, and is not particularly limited to the cross-sectional shape.

[0021]

As described above, according to the sliding throttle valve type carburetor according to the present invention, the upstream end opens at the bottom of the sliding throttle valve with a large groove width on the side surface on the air cleaner side, and the downstream end is the engine. A flow rectifying groove having a small groove width is provided in the vicinity of the bottom of the side throttle, and when the sliding throttle valve opens the intake path, the bottom of the engine-side side of the sliding throttle valve slides. Moved to the air cleaner side according to the opening degree of the dynamic throttle valve, and increased the distance between the bypass hole and the bottom of the engine side surface of the sliding throttle valve, so that the engine's minimum idling opening degree to off-idling opening degree Up to the intermediate opening range, the low-speed fuel can be properly sucked out without interruption, and the low-speed fuel can be finely refined.Thus, the minimum opening operation including the minimum idling operation and the off-idling operation can be performed extremely smoothly and Do well Those that could be.

[Brief description of the drawings]

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

FIG. 2 is a right side view of FIG.

FIG. 3 is a bottom plan view of FIG. 1;

FIG. 4 is a longitudinal sectional view showing one embodiment of a sliding throttle valve type carburetor of the present invention.

[Description of Signs] 1 Sliding throttle valve 1A Side surface on air cleaner side 1B Side surface on engine side 1C Bottom part on side surface on engine side 2 Bottom part 3 Rectifying groove 3A Upstream end 3B Downstream end 13 Bypass hole A Air cleaner side B Engine side

Claims (1)

[Claims] 1. A sliding throttle valve is movably arranged in a throttle valve guide cylinder connected to an intake passage penetrating a carburetor body,
In a sliding throttle valve carburetor in which an intake passage is controlled to be opened and closed by a sliding throttle valve and a bypass hole of a low-speed fuel system is opened near a bottom of an engine side surface of the sliding throttle valve,
The sliding throttle valve 1 includes an air cleaner side surface 1A formed on the air cleaner side A of the longitudinal axis XX, an engine side surface 1B formed on the engine side B, and an engine side surface 1B.
The bottom 2 is directed from the bottom 1C of the sliding throttle valve 1 toward the side surface 1A on the air cleaner side located at an upper position on the longitudinal axis XX of the sliding throttle valve 1, and the bottom end 2 is provided with the upstream end 3A on the side surface 1A on the air cleaner side. Open with a large groove width D, downstream end 3
B is a small groove width E near the bottom 1C of the engine side surface 1B.
And a rectifying groove 3 connected with the sliding throttle valve 1.
When the intake path 7 is opened, the bottom 1C of the engine-side side surface 1B of the sliding throttle valve 1 is moved to the air cleaner side A in accordance with the opening degree of the sliding throttle valve 1, and slides with the bypass hole 13. Distance L between dynamic throttle valve 1 and bottom 1C of engine side surface 1B
Sliding throttle valve type carburetor with increased number.