JP2001159371A - Accelerating/decelerating device for carburetor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly decelerate an engine without generating an engine stall by rapidly closing a throttle valve up to the specified opening, while gradually closing the throttle valve at the specified opening or less in the closing action of the throttle valve. SOLUTION: This accelerating/decelerating device for a carburetor is provided with a pressure chamber 26 communicating with an air bleed chamber 14 of the carburetor, and a diaphragm 25 for increasing/decreasing the volume of the pressure chamber 26. The diaphragm 25 is interlocked to decrease the volume of the pressure chamber 26 in the opening operation of a throttle valve 8 and to increase the volume of the pressure chamber 26 in the closing operation. A plurality of air passages 42, 43 provided with throttle parts 40, 41 are connected to the pressure chamber 26, and a valve mechanism 45 is provided for closing at least one air passage when the throttle valve 8 has a specified opening or less. The inflow of air into the pressure chamber 26 is thereby increased up to the specified opening to rapidly close the throttle valve 8, while the inflow of air into the pressure chamber 26 is reduced at the specified opening or less to gradually close the throttle valve 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carburetor acceleration / deceleration device.

[0002]

2. Description of the Related Art Conventionally, a pressure chamber communicating with an air bleed chamber and a diaphragm for increasing or decreasing the volume of the pressure chamber have been provided as an accelerating / decelerating device for a carburetor. By interlocking to increase the volume of the pressure chamber at the time of closing operation, pressurized air is pushed out to the air bleed chamber at the time of opening the throttle valve, promoting fuel ejection from the main nozzle and good acceleration. At the same time, when the throttle valve is closed, the air velocity sucked into the pressure chamber is controlled by a jet to generate a negative pressure in the pressure chamber to gradually close the throttle valve. A vessel acceleration / deceleration device is known. In such an acceleration / deceleration device, when the throttle valve is closed from near full open,
Since the throttle valve is gradually closed by the negative pressure generated in the pressure chamber, the time until the throttle valve closes becomes long, and there is a disadvantage that the engine cannot be quickly decelerated.

[0003]

SUMMARY OF THE INVENTION According to the present invention, when the throttle valve is closed, the throttle valve is quickly closed to a predetermined opening and gradually closed at a predetermined opening or less. Provided is an acceleration / deceleration device that quickly decelerates an engine without causing a stall.

[0004]

According to the present invention, there is provided a valve for connecting a plurality of air passages each having a throttle to a pressure chamber and closing at least one of the air passages when the throttle valve has a predetermined opening degree or less. Provide a mechanism. Thus, up to a predetermined opening of the throttle valve, the flow of air into the pressure chamber is increased to reduce the negative pressure of the pressure chamber to quickly close the throttle valve. The amount of air flowing into the pressure chamber is reduced, the negative pressure in the pressure chamber is increased, and the throttle valve can be gradually closed, so that the engine is quickly decelerated without generating engine stall.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described based on one embodiment of the present invention illustrated in the accompanying drawings. 1 and 2, reference numeral 1 denotes a carburetor, and an intake path 3 is provided through the carburetor body 2 so that the intake path 3
The upstream side is connected to an air cleaner (not shown), and the downstream side is connected to an intake port (not shown) of the engine 5 via the intake manifold 4. A venturi 6 is provided at the center of the intake passage 3. A choke valve 7 is provided upstream of the venturi 6, and a throttle valve 8 is provided downstream of the venturi 6.
Is disposed, and a throttle shaft 20 of the throttle valve 8 is provided.
A throttle lever 21 is fixed to an outer end of the throttle lever. Also,
The throttle valve 8 is normally urged in a closing direction by a return spring (not shown).

[0006] A fuel chamber 10 is provided below the intake path 3. Further, the carburetor body 2 is provided with a main nozzle boss 11 projecting into the fuel chamber 10.
The main nozzle 12 is accommodated therein. The upper end of the main nozzle 12 faces the intake path 3 and the lower end of the main nozzle 1
3 and is communicated below the oil level of the fuel chamber 10. An air bleed chamber 14 is provided around the main nozzle 12, and the air bleed chamber 14 is communicated with an inner hole 16 of the main nozzle by a plurality of bleed holes 15 provided in the main nozzle 12. A main air passage 17 is connected to the air bleed chamber 14, and the main air passage 1
The other end of 7 is connected to the intake path 3 upstream of the venturi 6 or an air cleaner (not shown) or the atmosphere via a jet 18. Therefore, the fuel passing through the main nozzle 12 is mixed with the air in the air bleed chamber 14 through the bleed hole 15 to be emulsified and sucked into the intake passage 3.

Reference numeral 24 denotes a casing of the acceleration pump 23 in which a diaphragm 25 is stretched.
5 partitions the pressure chamber 26 and the atmosphere chamber 27. The pressure chamber 26 is connected to the air bleed chamber 14 by a pressure passage 28. A base end of a rod 29 protruding toward the atmosphere chamber 27 is attached to the diaphragm 25, and a distal end of the rod 29 protrudes out of the casing through a through hole 37 provided in the casing 24 and is connected to the throttle lever 21. You. The diaphragm 25 is moved to the side where the volume of the pressure chamber 26 is reduced when the throttle valve 8 is opened, and conversely, when the throttle valve 8 is closed.
Is moved to the side that increases the volume of the vehicle.

When the diaphragm 25 moves in a direction to reduce the pressure chamber 26 between the pressure passage 28 and the pressure chamber 26, the valve is pushed by the air from the pressure chamber 26 to open the valve. A check valve 30 is provided which is closed when 25 moves in a direction to expand the pressure chamber 26.

The check valve 30 is of a diaphragm type and has a valve chamber 33 connected to the pressure chamber 26 by a passage 31. A valve seat 34 is provided around the opening of the passage 31 on the valve chamber 33 side. Is formed, and a diaphragm valve 35 is stretched facing the valve seat 34. Therefore, during acceleration, when the diaphragm 25 contracts the pressure chamber 26 due to the opening of the throttle valve 8, the air in the chamber 26 opens the diaphragm valve 35 and is pushed out to the air bleed chamber 14, and the air bleed chamber 14 is released. Is increased, and the ejection of fuel from the main nozzle 12 is promoted. On the other hand, at the time of deceleration, when the diaphragm 25 expands the pressure chamber 26 with the closing of the throttle valve 8, the pressure chamber 27 becomes a negative pressure, so that the diaphragm valve 35 comes into close contact with the valve seat 34 and closes the passage 31. The pressure chamber 26 and the air bleed chamber 14 are shut off.

In the above example, the check valve 30 is of a diaphragm type. However, the present invention is not limited to this. For example, a ball valve, a tongue valve, and other generally known check valves may be used. It is possible to use.

A valve seat 38 is formed around the through hole 37 in the atmosphere chamber 27. The pressure chamber 26 is connected to air suction passages 42 and 43 having throttle portions 40 and 41. The other end of one air suction passage 42 is open to the valve seat 38, and the other end of the other air suction passage 43 is open to the atmosphere.

The acceleration pump 23 is provided with a valve mechanism 45 which is seated on the valve seat 38 and closes the opening 42a of the air suction passage 42 at a predetermined opening degree of the throttle valve 8 or less. The valve mechanism 45 has a cylindrical portion 47 having an outer periphery slidably fitted in the through hole 37 and slidably inserting the rod 29 into the inner hole 46, and a casing 24 of the cylindrical portion 47.
50 having a flange portion 48 formed on one side facing the
A clip 44 attached to a predetermined position of the rod 29; and a clip 44 disposed between the valve body 50 and the diaphragm 25 to urge the valve body 50 toward the distal end of the rod 29, And a spring 51 for contacting the clip 44 with the clip 44. Therefore, when the throttle valve 8 is not more than the predetermined opening degree, as shown in FIG.
Since the seat 8 is seated on the valve seat 38, the rod 29 slides in the inner hole 46 of the valve seat 38 to drive the diaphragm. When the throttle valve 8 has a predetermined opening degree or more, as shown in FIG. 2, the flange portion 48 of the valve body 50 separates from the valve seat 38, and the valve body 50 moves integrally with the rod 29. The rod 29 is slid while being supported by the outer periphery of the cylindrical portion 47 of the valve body 50, and the diaphragm 25 is driven. 53 is a seal member attached to the valve seat 38 side of the flange portion 48. Although there is no particular need to attach this seal member 53, the intake air passage 42 formed by the valve body 50 is provided.
It is desirable to attach the opening 42a in order to improve the sealing performance.

The operation of the above embodiment will be described below. When the throttle valve 8 is opened, the diaphragm 25 is moved in a direction to reduce the volume of the pressure chamber 26, and the pressure chamber 26
The air inside is pushed out to the air bleed chamber 14 via the check valve 30, the air pressure in the air bleed chamber 14 rises, and the fuel is pushed out from the main nozzle 12, and acceleration is performed smoothly. When the throttle valve 8 is closed, the diaphragm 25 moves in a direction to increase the volume of the pressure chamber 26, the check valve 30 of the pressure passage 28 is closed, and the air suction passages 42 and 43 are throttled to the pressure chamber 26. Part 4
The air is sucked under the control of 0.41.

When the throttle valve 8 has a predetermined opening or less, the flange 48 of the valve body 50 is seated on the valve seat 38 so that the air suction passage 42 is closed by the flange 48 and the pressure chamber 26 is moved to the pressure chamber 26. Is introduced only through the air inflow passage 43, so that the moving speed of the diaphragm 25 becomes very slow, whereby the throttle valve 8 is gradually closed. As a result, the throttle valve 8 can be closed quickly up to a predetermined opening degree, and can be closed gently below the predetermined opening degree, so that the engine can be quickly decelerated without causing engine stall and the throttle valve 8 Can be reduced by the rapid closing of the fuel cell.

[0015]

As described above in detail, according to the present invention, a pressure chamber communicating with an air bleed chamber of a carburetor and a diaphragm for increasing or decreasing the volume of the pressure chamber are provided, and the diaphragm operates to open a throttle valve. In a carburetor acceleration / deceleration device interlocked to reduce the volume of the pressure chamber at times and increase the volume of the pressure chamber at the time of closing operation, a plurality of air passages having a throttle portion are connected to the pressure chamber, and at least one By providing a valve mechanism that closes the air passage when the throttle valve is less than a predetermined opening, the amount of air sucked into the pressure chamber is reduced below the predetermined opening to gradually close the throttle valve. As a result, the engine can be quickly decelerated without causing engine stall, and the generation of hydrocarbons due to the rapid closing of the throttle valve 8 can be reduced. Kill.

Further, the valve mechanism can weaken the closing force of the throttle valve by urging the diaphragm in the opening direction of the throttle valve at a predetermined opening degree or less by the action of a spring. Even when the negative pressure in the pressure chamber is weak, the throttle valve can be gradually closed surely.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of the acceleration / deceleration device of the present invention when a throttle valve has a predetermined opening degree or more.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vaporizer 3 Intake path 8 Throttle valve 12 Main nozzle 14 Air bleed chamber 25 Diaphragm 26 Pressure chamber 29 Rod 30 Check valve 37 Through hole 38 Valve seat 40, 41 Throttle part 42, 43 Air intake passage 50 Valve body

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 7/08 F02M 7/08 H 7/23 7/23 B

Claims (2)

[Claims] 1. A pressure chamber communicating with an air bleed chamber of a carburetor, and a diaphragm for increasing or decreasing the volume of the pressure chamber, wherein the diaphragm reduces the volume of the pressure chamber when the throttle valve is opened and closes when the throttle valve is closed. In an accelerating / decelerating device for a carburetor linked to increase the volume of a pressure chamber, a plurality of air passages each having a throttle portion are connected to the pressure chamber, and at least one air passage is connected to a predetermined position by the throttle valve. An accelerating / decelerating device for a carburetor, comprising a valve mechanism that closes when the opening degree is less than an opening degree. 2. A pressure chamber communicating with an air bleed chamber of a carburetor, and a diaphragm for increasing or decreasing the volume of the pressure chamber, wherein the diaphragm reduces the volume of the pressure chamber when the throttle valve is opened and operates when the throttle valve is closed. In the accelerating and decelerating device of a carburetor linked to increase the volume of a pressure chamber, a valve mechanism resiliently mounted on a throttle valve side is slidably fitted to a rod connecting the diaphragm and a throttle valve. A plurality of air passages each having a throttle portion are connected to the pressure chamber, and the other end of at least one air passage is opened to a seating surface of the valve mechanism. An acceleration / deceleration device for a carburetor, wherein the one air passage is closed by contacting the seating surface.