JPH084594A - Drain device for carburetor for gasoline engine - Google Patents

Abstract

PURPOSE:To perform drain operation of a carburetor through simple operation during storage of a gasoline engine for a long period. CONSTITUTION:A discharge passage 7 for residence fuel extending from a float chamber 3 to a venturi 4 is provided. The inlet 7a thereof is opened in such a state to approach the bottom wall 3a of a float chamber 3 below a main jet 6 and the outlet 7b thereof is opened to the venturi 4 and a throttle valve 8 is located in a discharge passage 7 for residence fuel. By utilizing the negative pressure of the venturi 4 by closing operation of a choke valve, residence fuel in the float chamber 3 is sucked out to the venturi 4 through the discharge passage 7 for residence fuel, whereby in preservation of an engine for a long period, drain operation is simply effected through operation of a choke valve protruded to a position above a carburetor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drain device for a carburetor for a gasoline engine, and provides a drain device capable of efficiently discharging the residual fuel in the carburetor when the engine is stored for a long time.

[0002]

BACKGROUND OF THE INVENTION The basic structure of a carburetor for a gasoline engine, which is the subject of the present invention, is as shown in FIG. 1 or 4, in which a carburetor 1 for a gasoline engine E comprises a wind tunnel portion 2 and a float chamber 3, The main nozzle 5 is provided from the float chamber 3 toward the venturi 4 of the wind tunnel 2, and the main jet 6 of the main nozzle 5 is arranged in the lower part of the float chamber 3.

[0003]

2. Description of the Related Art If the gasoline engine is turned off by a normal operation of shutting down the fuel, the fuel remains in the float chamber 3 to a position slightly above the main jet 6. Therefore, if the engine is stored for a long time as it is, the residual fuel in the float chamber 3 will deteriorate into a gum shape over time, and the main jet 6 will be clogged, which may cause a start failure at the time of starting after storage. Is big. Therefore, when the gasoline engine is stored for a long time, it is necessary to discharge the residual fuel in the carburetor in advance and perform the drain operation before the storage.

As a conventional technique of the drain device of the carburetor, as shown in JP-A-5-27276 (see FIG. 4), a drain passage 50 is provided below the float chamber 3 of the carburetor 1.
, A fuel switching valve 53 is interposed between the float chamber 3 and the main jet chamber 51, and the fuel switching valve 53 is interlocked with the fuel cock 52.

In the prior art, when the gasoline engine E is stored for a long period of time, first, the fuel cock 52 is rotated to switch the fuel switching valve 53 to the stop drain position to shift the float chamber 3 to the main jet chamber 51. The jet communication path 54 is opened, the jet communication path 54 is connected to the drain passage 50, and the residual fuel in the float chamber 3 is discharged to the outside for drain operation. Next, the fuel switching valve 53 is switched to the stopped storage position, the jet communication passage 54 and the drain passage 50 are closed, and the main jet 6 is shut off from the float chamber 3.

[0006]

In the above-mentioned prior art, the fuel cock 52 is switched to the stop drain position to discharge the residual fuel in the float chamber 3 through the drain passage 50, so that the hands can be kept clean. The drain can be operated.

On the other hand, in an engine working machine such as an agricultural machine or a generator, the engine is usually housed in a bonnet or a soundproof case of the working machine. Therefore, in the above-described conventional technique that requires manual operation of the fuel cock 52, the fuel cock 5
Since 2 faces the so-called retracted position on the lower side of the carburetor 1, there is a risk that it may interfere with peripheral devices and cannot be easily operated manually.
SUMMARY OF THE INVENTION It is a technical object of the present invention to drain a carburetor with a simple operation during long-term storage of a gasoline engine.

[0008]

Means for achieving the above object will be described below with reference to FIGS. 1 to 3 showing an embodiment. That is, the present invention 1 is a carburetor for a gasoline engine having the above basic structure, in which a residual fuel discharge passage 7 is provided from the float chamber 3 toward the venturi 4, and an inlet 7a of the residual fuel discharge passage 7 is located below the main jet 6. The residual fuel discharge passage 7 is opened at a portion close to the bottom wall 3a of the float chamber 3.
Is a drain device for a carburetor of a gasoline engine, characterized in that an outlet 7b is opened in the venturi 4 and a throttle valve 8 is provided in the residual fuel discharge passage 7.

According to the second aspect of the present invention, in the first aspect of the present invention, the key switch 20 can be operated to be turned on / off or opened / closed with respect to the spark plug 21, the starter motor 22, and the valve drive device 23 of the choke valve 10 of the carburetor 1. Key switch 20
When the cleaning position CL is set to and the key switch 20 is switched to the cleaning position CL, the power supply to the spark plug 21 is stopped, the starter motor 22 is driven, and the choke valve 10 of the carburetor 1 is closed by the valve drive device 23. It is characterized by being configured as described above.

[0010]

[Action]

(1) The present invention 1 is characterized in that a discharge passage 7 for residual fuel is provided from the float chamber 3 toward the venturi 4. Therefore, when the gasoline engine E is stored for a long period of time, when the choke valve 10 of the carburetor 1 is closed, a negative pressure is generated in the venturi 4 due to the inertial rotation of the engine E after the operation.
Due to this negative pressure, the residual fuel in the float chamber 3 is sucked into the wind tunnel portion 2 through the residual fuel discharge passage 7.

In this case, the inlet 7a of the residual fuel discharge passage 7
Is the bottom wall 3a of the float chamber 3 below the main jet 6.
Since the opening is made in a portion approaching to, the residual fuel in the float chamber 3 is almost entirely discharged, and it is possible to reliably prevent the gum substance from sticking around the main nozzle 5. Further, normally, the throttle valve 8 provided in the residual fuel discharge passage 7 has a flow rate set in accordance with the case where the choke valve 10 is closed, and is narrowed down from the main jet 6, so that the fuel flows during normal operation. It is not sucked out of the wind tunnel portion 2 through the residual fuel discharge passage 7.

Moreover, when the operation is stopped normally, the drain operation during the long-term storage is not performed, and the engine E is simply turned to the end, so that the fuel around the main jet 6 remains in the float chamber 3. For this reason, not all residual oil in the float chamber 3 is discharged, so that the float chamber 3 can be promptly filled with fuel by that amount at the time of startup,
The engine E can be started quickly.

(2) In the second aspect of the present invention, when the key switch 20 is switched to the cleaning position CL, the power supply to the spark plug 21 is stopped, but the starter motor 22 is driven to move the piston up and down and the carburetor 1 of the carburetor 1 is moved. The choke valve 10 is closed by the valve drive device 23. Since the choke valve 10 is closed, a negative pressure is strongly generated in the venturi 4,
The residual fuel in the float chamber 3 is strongly sucked into the wind tunnel 2 via the residual fuel discharge passage 7.

[0014]

【The invention's effect】

(1) In the present invention 1, the residual fuel discharge passage is provided from the float chamber to the venturi, and the fuel remaining in the float chamber is discharged to the residual fuel discharge passage by utilizing the negative pressure of the venturi accompanying the closing operation of the choke valve. Since it is sucked into the venturi through the, the residual fuel in the float chamber can be drained by a simple operation when the gasoline engine is stored for a long time.
That is, in the related art described above, the residual fuel is discharged from below the float chamber 3 by its own weight, but the present invention 1 sucks out the residual fuel by using the negative pressure of the venturi. Has a different drain principle. Moreover, even in an engine working machine in which the engine is housed in the bonnet, only the choke valve protruding above the carburetor is operated, so that the drain operation is not hindered by the conflict with peripheral devices.

(2) In the present invention 2, when the gasoline engine is stored for a long period of time, the residual fuel in the float chamber can be automatically discharged simply by switching the key switch to the cleaning position, which facilitates drain operation. It will be easy. Further, the negative pressure effect of the Venturi 4 is sufficiently enhanced by the piston movement accompanying the operation of the cell starter, so that the residual fuel can be strongly sucked out. In particular, even in the engine working machine, since the key switch is simply operated without opening the hood, the drain can be operated easily.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view of a drain device of a carburetor, FIG. 2 is a principle diagram of a drain operation of the carburetor, and FIG. 3 is a schematic operation system diagram of a drain device of a carburetor of a vertical gasoline engine.

As shown in FIG. 3, the carburetor 1 is provided in the intake passage of the vertical gasoline engine E, and the choke valve 1 of the carburetor 1 is provided.
The output rod 23a of the solenoid 23 is engaged with 0, and the starter motor 22 is interlocked with the flywheel 11.

As shown in FIGS. 1 and 2, the carburetor 1 has a wind tunnel portion 2 forming a venturi 4, a cylindrical boss portion 12 that hangs integrally from the wind tunnel portion 2, and is fastened to the boss portion 12. It is composed of a float chamber 3 which is detachably fixed via a bolt 13, an annular float 14 which is housed in the float chamber 3 around the boss portion 12, and a needle valve 15 which is arranged so as to be able to contact the float 14. It The rod-shaped main nozzle 5 is fitted into the boss portion 12, and the main jet 6 of the main nozzle 5 is arranged in the lower portion of the float chamber 3,
The float chamber 3 is communicated with the main jet 6 through the fuel inlet 16 of the main nozzle 6, and the outlet 5b at the upper end of the main nozzle 5 is projected into the venturi 4 of the wind tunnel 2.

As shown in FIGS. 1 and 2, a residual fuel discharge passage 7 is provided from the float chamber 3 toward the venturi 4, and an inlet 7a of the residual fuel discharge passage 7 is connected to the main jet 6
An opening is made in a lower portion of the float chamber 3 which is close to the bottom wall 3a, and an outlet 7b of the residual fuel discharge passage 7 is opened in the venturi 4. That is, the residual fuel discharge passage 7 is a discharge passage 18 that penetrates the wall forming the wind tunnel portion 2 in a curved shape.
A discharge pipe 17 having a thin tubular shape arranged in parallel with the boss portion 12. One end of the discharge passage 18 is opened to the venturi 4 via the outlet pipe 19, and the discharge portion is opened to the base end portion of the boss portion 12. The discharge pipe 17 is fixed to the other end 18a of the passage 18. Further, the throttle valve 8 is provided in the discharge passage 18, the throttle diameter of the throttle valve 8 is set to be smaller than that of the main jet 6, and the fuel flows through the residual fuel discharge passage 7 during normal operation to wind tunnel 2 It is prevented from being sucked out from the valve, and the flow rate is adjusted according to the case where the choke valve 10 is closed.

As shown in FIG. 3, the key switch 20 of the gasoline engine E has the operating position ON and the stop position OF.
F and the starting position ST are set, and a cleaning position CL is newly set. The key switch 20 is interlocked with the spark plug 21 and the starter motor 22 so that the key switch 20 can be turned on and off, and the solenoid 23 of the choke valve 10 of the carburetor 1 can be operated.
It can be opened and closed. When the key switch 20 is switched to the cleaning position CL, power supply to the spark plug 21 is stopped, the starter motor 22 is driven, and the choke valve 10 of the carburetor 1 is closed.

Therefore, the function of the drain device of the carburetor of the vertical gasoline engine of this embodiment will be described. When the gasoline engine E is stored for a long time with this drain device,
The key switch 20 is switched to the cleaning position CL and operated. When this operation is performed, as shown in FIGS.
The power supply to the spark plug 21 is stopped, the starter motor 22 is driven to move the piston up and down, and the solenoid 23
Is activated to drive the choke valve 10 of the carburetor 1 to be closed.
(See arrow P in FIG. 2). For this reason, as shown in FIG. 2, a negative pressure is strongly generated in the venturi 4 by the piston movement, so that the fuel remaining in the float chamber 3 passes through the residual fuel discharge passage 7 and the wind tunnel 2 Is strongly sucked into. Moreover, since the inlet 7a of the residual fuel discharge passage 7 opens below the main jet 6, almost all the residual fuel in the float chamber 3 is discharged, and it is ensured that the gum substance sticks around the main nozzle 5. It can be prevented.

As described above, in this embodiment, the engine E is
In the case of storing for a long period of time, almost all the residual fuel in the float chamber 3 can be automatically discharged only by switching the key switch 20 to the cleaning position CL, so that the drain operation becomes extremely simple. Especially for engine working machines, the key switch 20 can be used without opening the hood.
You can easily operate the drain as you only operate.

On the other hand, at the time of normal operation stop, the key switch 20 is switched to the stop position OFF instead of the cleaning position CL, but at the time of this normal stop, the drain operation during the long-term storage is not performed, and the engine E is simply turned off. Only. For this reason, instead of discharging the entire amount of residual oil in the float chamber 3, the fuel at the peripheral level of the main jet 6 remains, so that the float chamber 3 can be quickly filled with fuel at the time of startup, and the engine E can be quickly started. .

In the present invention, the residual fuel in the float chamber 3 of the carburetor 1 is sucked out to the venturi 4 by the residual fuel discharge passage 7 during long-term storage of the gasoline engine.
Therefore, the discharge passage 7 may be configured to penetrate the meat wall of the boss portion 12 and communicate with the venturi 4, for example. Alternatively, the discharge passage 7 may be a discharge pipe that passes outside the carburetor 1.
The lower part of the and the venturi 4 may be configured to communicate with each other.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a drain device of a vaporizer.

FIG. 2 is a principle diagram of a drain operation of a vaporizer.

FIG. 3 is a schematic operation system diagram of a drain device of a carburetor of a vertical gasoline engine.

FIG. 4 is a view equivalent to FIG. 1 showing a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vaporizer, 2 ... Wind tunnel part, 3 ... Float chamber, 4 ... Venturi, 5 ... Main nozzle, 6 ... Main jet, 7 ... Residual fuel discharge passage, 7a ... Discharge passage inlet, 7b ... Discharge passage outlet, 8 ... Throttle valve, 10 ... Choke valve, 20 ... Key switch, 21 ... Spark plug, 22 ... Cell motor, 23 ... Choke valve valve drive device, CL ... Cleaning position, E ... Gasoline engine.

Claims (2)

[Claims] 1. A carburetor (1) for a gasoline engine (E) comprises a wind tunnel (2) and a float chamber (3), and the float chamber (3)
From the main nozzle toward the venturi (4) of the wind tunnel (2)
In a carburetor for a gasoline engine in which (5) is provided and the main jet (6) of the main nozzle (5) is arranged in the lower part of the float chamber (3), the residual fuel is discharged from the float chamber (3) toward the venturi (4). The discharge passage (7) is provided, and the inlet (7a) of the residual fuel discharge passage (7)
The bottom wall of the float chamber (3) below the main jet (6)
Residual fuel discharge channel (7) that opens at a portion approaching (3a)
A drain device for a carburetor of a gasoline engine, characterized in that the outlet (7b) is opened to the venturi (4) and a throttle valve (8) is provided in the residual fuel discharge passage (7). 2. A key switch (20) is connected to a spark plug (21), a starter motor (22) and a valve drive device (23) of a choke valve (10) of a carburetor (1) for opening / closing or opening / closing operations. The key switch (10) is in the cleaning position in conjunction with the operation.
(CL) is set and the key switch (10) is switched to the cleaning position (CL), power supply to the spark plug (21) is stopped, the starter motor (22) is driven, and the choke valve of the carburetor (1) is driven. The drain device for a carburetor of a gasoline engine according to claim 1, wherein the valve drive device (23) closes the valve (10).