JPH0678741B2 - Auxiliary fuel supply device for carburetor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a starter for a small engine equipped with a diaphragm carburetor.

<Prior Art> Generally, a small engine equipped with a diaphragm type carburetor is
It is necessary to fill the fuel chamber of the carburetor with fuel before starting. Therefore, in the past,
As disclosed in Japanese Patent No. 43315, a manual pump that feeds fuel in a fuel tank to the fuel chamber, a diaphragm of the fuel chamber is pushed up, and a fuel valve at an inlet of the fuel chamber is forcibly opened and at the same time an overflow valve is opened. A mechanism is provided that has a Ticla lever that opens, and that operates this manual pump and the Ticla lever at the same time before starting the engine to introduce fuel into the fuel chamber, and that detects that the fuel chamber has been filled with fuel from a fuel overflow. ing.

Further, in order to facilitate starting of the engine, it is desirable to supply a rich air-fuel mixture at the time of starting, but even if the fuel chamber is filled with fuel, the amount of fuel supplied from the nozzle is suitable for the starting operating condition. Therefore, in order to supply a desired rich air-fuel mixture to the engine, it is necessary to further operate the choke valve to limit the intake air amount.

<Problems of Prior Art> As described above, in the above device, it is necessary to operate both the manual pump and the ticker lever at the time of starting, and therefore both hands are required and the handling is troublesome. Furthermore, after the fuel chamber is filled with fuel, it is necessary to perform a choking operation in order to obtain a rich mixture for starting, and these operations are very troublesome.

<Purpose> An object of the present invention is to solve the above-mentioned troublesome work at the time of starting and to provide an auxiliary fuel supply device for supplying a rich air-fuel mixture for engine starting without using a choke mechanism.

<Structure of the Invention> According to the present invention, two auxiliary fuel storage chambers are provided side by side in the middle of a fuel discharge passage of a fuel pump connected to a diaphragm chamber of a carburetor, and these auxiliary fuel storage chambers are provided on the fuel discharge passage. And a switching means for electrically connecting the auxiliary fuel storage chamber on the non-connection side to the intake passage of the carburetor.

<Operation> During operation of the engine, the fuel fed by the fuel pump is fed to the diaphragm chamber of the carburetor through the auxiliary fuel storage chamber on the side connected by the switching means. Therefore, the auxiliary fuel storage chamber is filled with fuel while the engine is operating, and the fuel is stored in the auxiliary fuel storage chamber even after the engine is stopped.

Then, at the next engine start, by switching the switching means, the auxiliary fuel storage chamber is connected to the intake passage of the carburetor and the fuel discharge passage of the fuel pump is connected to the other auxiliary fuel storage chamber. When the engine is started, the fuel in the auxiliary fuel storage chamber is supplied to the intake passage and mixed with the air flowing in from the upstream side of the intake passage to generate the starting air-fuel mixture.

When the engine is started, the fuel sent by the fuel pump is sent to the diaphragm chamber of the carburetor through the other auxiliary fuel storage chamber in the same manner as above, and the auxiliary fuel storage chamber is filled with fuel for the next startup. Prepare

<Examples> Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing an auxiliary fuel supply system of the present invention.

1 is a vaporizer according to the present invention. Main body 2 of this vaporizer 1
The intake passage 3 is provided so as to penetrate therethrough, and the throttle valve 4 faces the intake passage 3 from above in a freely movable manner. A fuel nozzle 5 is opened in the bottom wall of the intake passage 3 below the throttle valve 4, and a jet needle 6 depending from the throttle valve 4 is inserted into the fuel nozzle 5. The fuel nozzle 5 communicates with a diaphragm chamber 8 via a fuel orifice 7.

Further, the carburetor 1 is provided with a fuel pump 10 that operates by pulsation of an engine (not shown). A fuel intake passage 11 and a fuel discharge passage 12 are connected to the fuel pump 10, and the fuel intake passage 11 has a connection port 14 to a fuel tank 13.
And the fuel discharge passage 12 is connected to the diaphragm chamber 8.

The diaphragm chamber 8 has a bottom wall formed by a diaphragm 15, and the fuel discharge passage 12 is connected to the fuel discharge passage 12 at the inlet of the diaphragm chamber 8.
There is provided a fuel valve 16 which is operated to connect and disconnect, that is, to connect and disconnect the fuel pump 10 and the diaphragm chamber 8. A support shaft 17 is provided between the fuel valve 16 and the diaphragm 15.
A lever 18 is provided having one end connected to the fuel valve 16 and the other end connected to the diaphragm 15 with the support shaft 17 as the center. Therefore, when a strong negative suction pressure acts on the diaphragm chamber 8 through the fuel nozzle 5, the diaphragm 15 moves upward to introduce the fuel from the fuel pump 10 into the diaphragm chamber 8 through the fuel discharge passage 12. The fuel valve 16 is held in the open position via the. Further, when the strong negative pressure in this chamber 8 disappears due to the introduction of fuel into the diaphragm chamber 8, the fuel valve 16 prevents the introduction of fuel into the diaphragm chamber 8 by the biasing force of the compression spring 19 which engages with the lever 18. In order to do so, the fuel discharge passage 12 is shut off.

A switching means is provided in the fuel discharge passage 12 of the fuel pump 10.
Two auxiliary fuel storage chambers 21 and 22 are provided via 20 and the switching means 20 switches the connection between the auxiliary fuel storage chambers 21 and 22 and the fuel discharge passage 12 alternately. That is, the inflow passages 23, 24 of the auxiliary fuel storage chambers 21, 22 are
And the outflow side passages 25 and 26 are connected to the fuel discharge passage 12 of the fuel pump via the switching means 20, respectively.
By switching 20 the fuel sent from the fuel pump 10 is sent to the diaphragm chamber 8 of the carburetor through one of the auxiliary fuel storage chambers, and the fuel is automatically stored in the chamber. ing.

Further, the outlet side passage 25 of the auxiliary fuel storage chamber on the non-connection side or
The switching means 20 is connected to the starting fuel passage 27 opened to the intake passage 3 of the carburetor by the switching means 20 so as to supply the fuel stored in the chamber 21 or 22 to the intake passage 3.

In addition, above the auxiliary fuel storage chambers 21 and 22, the chambers 21 and
Check valves 28 and 29 are provided to allow the inflow of air into the inside 22 of the auxiliary fuel storage chamber 21 or 22 on the non-connection side to the intake passage 3
The fuel is smoothly discharged to the. On the other hand, when the auxiliary fuel storage chamber 21 or 22 is connected to the fuel discharge passage 12 and fuel flows into the chamber, the check valve 28 or 29 is closed by the fuel pressure and the fuel flows out. Is being prevented.

Reference numeral 30 is a manual pump arranged upstream of the switching means 20. It is not necessary to provide the manual pump 30, but it is desirable to provide the manual pump 30 because the fuel can be quickly replenished to the auxiliary fuel storage chamber 21 or 22 when the auxiliary fuel storage chamber 21 or 22 is empty for a long period of time.

The operation of the present invention configured as described above will be described, for example, based on the case where the auxiliary fuel storage chamber 21 and the fuel discharge passage 12 are connected by the switching means 20 as shown in FIG. The fuel fed by the fuel pump 10 is fed to the diaphragm chamber 8 of the carburetor through the auxiliary fuel storage chamber 21 connected by the switching means 20. Therefore, the auxiliary fuel storage chamber 21 is filled with fuel during the operation of the engine, and the fuel is stored in the chamber 21 even after the engine is stopped.

When the engine is started next time, the switching means 20 is switched to the side of the auxiliary fuel storage chamber 22 as shown in FIG. 2 so that the fuel discharge passage 12 is connected to the other auxiliary fuel storage chamber 22 and the auxiliary fuel is supplied. When the storage chamber 21 is connected to the intake passage 3 of the carburetor and the engine is started in this state, the fuel in the auxiliary fuel storage chamber 21 is supplied to the intake passage 3, and the fuel from the fuel nozzle 5 and the intake air The mixture is mixed with the air flowing in from the upstream side of the passage 3 to generate a mixture for starting.

When the engine is started, the fuel sent by the fuel pump 10 is sent to the diaphragm chamber 8 of the carburetor through the auxiliary fuel storage chamber 22 in the same manner as above, and the auxiliary fuel storage chamber 22 is filled with fuel, and the next time Prepare for starting.

4 and 5 show another embodiment of the present invention, in which auxiliary fuel storage chambers 21 and 22 are provided at a position higher than the opening of the starting fuel passage 27 on the intake passage 3 side, and the intake passage of the carburetor is shown. 3, a water absorbing member 31 is provided, and when the switching means 20 is switched, the fuel in the auxiliary fuel storage chamber 21 or 22 is discharged toward the water absorbing member 31 and is retained in the water absorbing member 31. It is configured to allow.

The auxiliary fuel adsorbed and held by the water absorbing member 31 is the vaporizer 1
Regardless of the posture, the water-absorbing member 31 is reliably retained unless negative pressure acts on the intake passage 3. Therefore, the retained fuel does not directly flow into the engine when the engine is not operating, and when the intake negative pressure is generated by starting the engine, the retained negative fuel causes the retained fuel to flow from the fuel nozzle 5 and the intake air. A rich mixture is taken into the engine together with the air taken in from the upstream side of the passage 3, and the engine startability is thereby enhanced.

Further, the auxiliary fuel adsorbed and held by the water absorbent member 31 is not sucked into the engine at once due to the intake negative pressure due to the start of the engine, but is sequentially sucked, so excessive fuel is supplied when the engine is started. As a result, it is possible to prevent the start-up failure and to extend the supply time of the reserved fuel, so that the starting operation of the engine can be smoothly performed.

<Advantages of the Invention> As described above, according to the present invention, the auxiliary fuel is automatically stored during the operation of the engine, and the auxiliary fuel is supplied to the engine at the next engine start to generate a rich mixture. I tried to improve the startability. The startability of the engine can be enhanced without using the Ticla mechanism and the choke mechanism, which were conventionally required in the diaphragm type carburetor, and the troublesome starting of the seed carburetor can be eliminated.

Further, in the above embodiment, an example in which the present invention is used in a diaphragm type carburetor equipped with a sliding throttle valve has been described, but the present invention is applied to a carburetor equipped with a throttle valve such as a butterfly type and a rotary type. However, the same effect can be obtained.

[Brief description of drawings]

1 and 2 are explanatory views showing an embodiment of the auxiliary fuel supply system of the present invention, and FIG. 3 is a vaporizer I- in FIG.
A sectional view taken along the line I, FIGS. 4 and 5 are sectional views showing another embodiment of the present invention. 1 ... Vaporizer, 3 ... Intake passage, 4 ... Throttle valve, 8 ... Diaphragm chamber, 10 ... Fuel pump, 20 ... Switching means, 21 ...
22 …… Auxiliary fuel storage chamber, 27 …… Fuel passage for starting.

Claims (1)

[Claims] 1. A device for increasing engine startability provided in a carburetor, comprising two auxiliary fuel storage chambers provided in parallel on a fuel discharge passage of a fuel pump connected to a diaphragm chamber of the carburetor. And an auxiliary fuel supply device for a carburetor, which includes switching means for alternately switching between the auxiliary fuel storage chamber and the fuel discharge passage and for connecting the auxiliary fuel storage chamber on the non-connection side to the intake passage of the carburetor. .